This registration statement on Form S-4 contains two prospectuses, as set forth below.

The resale prospectus is substantively identical to the primary offering prospectus, except for the following:

This registration statement includes a set of alternate pages after the end of the primary offering prospectus (the “Alternate Pages”) that form a part of the resale prospectus and not the primary offering prospectus. The primary offering prospectus excludes the Alternate Pages and will be used for the primary offering by Standard BioTools. The resale prospectus adds and substitutes the Alternate Pages and will be used for the resale offering by the selling securityholders named therein.

As previously announced, on June 6, 2026, Standard BioTools Inc., a Delaware corporation (“Standard BioTools”), entered into an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”) with Treeline Biosciences, Inc., a Delaware corporation (“Treeline”), and Siri Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Standard BioTools (“Merger Sub”), pursuant to which Standard BioTools and Treeline will combine in an all-stock merger upon the terms and conditions set forth in the Merger Agreement. In accordance with the Merger Agreement, (i) Merger Sub will merge with and into Treeline, with Treeline surviving as a wholly owned subsidiary of Standard BioTools (the “Merger” and, together with the other transactions contemplated by the Merger Agreement, the “Merger Transactions”), and (ii) at the effective time of the Merger (the “Effective Time”), Standard BioTools will file an amendment to its certificate of incorporation (the “Charter Amendment”) to (a) change its name to “Treeline Biosciences Holdings, Inc.” and (b) effect a reverse stock split (the “Reverse Stock Split”) of all outstanding shares of common stock, par value $0.001 per share, of Standard BioTools (the “Standard BioTools Common Stock”), if the Reverse Stock Split has not been effected prior to the Effective Time as permitted by the Merger Agreement.

As a result of the Merger, each share of Treeline common stock, par value $0.00001 per share (the “Treeline Common Stock”), issued and outstanding immediately prior to the Effective Time and each share of Treeline preferred stock, par value $0.00001 per share (the “Treeline Preferred Stock” and, together with the Treeline Common Stock, the “Treeline Capital Stock”), issued and outstanding immediately prior to the Effective Time (in each case, other than shares held in treasury and dissenting shares) will be converted into the right to receive a number of shares of Standard BioTools Common Stock based on an exchange ratio calculated in accordance with the Merger Agreement (described in more detail in the section titled “The Merger Agreement — Exchange Ratio” beginning on page 221 of the accompanying proxy statement/prospectus) (the “Exchange Ratio”), with the number of shares of Standard BioTools Common Stock that each holder of Treeline Capital Stock is entitled to receive being rounded down to the nearest whole share and computed after aggregating all shares of Treeline Capital Stock held by such holder. The Exchange Ratio is based on the relative capitalization of each of Treeline and Standard BioTools and assumes (i) an equity value for Treeline of $2.5 billion and (ii) an equity value for Standard BioTools equal to $460 million, reduced by the amount by which the Parent Net Cash (as defined in the Merger Agreement) is less than $449 million at the closing of the Merger (the “Closing”) or increased by the amount by which Parent Net Cash is more than $451 million at the Closing.

Following the Closing, former Standard BioTools stockholders are expected to hold approximately 16% of the combined company on a fully diluted basis, and former Treeline stockholders are expected to hold approximately 84% of the combined company on a fully diluted basis. Under certain circumstances further described in the Merger Agreement, the pro forma ownership percentages may be adjusted based on the amount of Parent Net Cash at Closing as finally determined in accordance with the Merger Agreement (described in more detail in the sections titled “The Merger Agreement — Exchange Ratio” and “The Merger Agreement — Calculation of Parent Net Cash” beginning on pages 221 and 222, respectively, of the accompanying proxy statement/prospectus). Based on Standard BioTools’ and Treeline’s capitalization as of June 3, 2026 and May 28, 2026, respectively, and taking into account Standard BioTools’ estimate of Parent Net Cash as of the Closing, and before giving effect to the proposed Reverse Stock Split, each share of Treeline Capital Stock is currently estimated to be entitled to receive approximately 11.6997 shares of Standard BioTools Common Stock. This ratio may increase or decrease as of the Closing based on the companies’ respective actual capitalizations as of the Closing and the actual amount of Parent Net Cash as of the Closing.

In addition, as of the Effective Time, Standard BioTools will assume Treeline’s 2021 Equity Incentive Plan and each outstanding option to purchase shares of Treeline Common Stock (each, a “Treeline Option”), whether vested or unvested. Each such Treeline Option so assumed by Standard BioTools will continue to have, and be subject to, the same terms and conditions applicable to such Treeline Option immediately prior to the Effective Time, except that (i) such Treeline Option will be exercisable for that number of shares of Standard BioTools Common Stock equal to the number of shares of Treeline Common Stock subject to such Treeline Option immediately prior to the Effective Time multiplied by the Exchange Ratio and rounded down to the next nearest share of Standard BioTools Common Stock, and (ii) the exercise price per share of each such Treeline Option will be the exercise price per share in effect for that Treeline Option immediately prior to the Effective Time divided by the Exchange Ratio and rounded up to the next nearest cent.

In addition, as of the Effective Time, (i) each warrant to purchase shares of Treeline Capital Stock (each, a “Treeline Warrant”) that has been amended to require net-exercise in connection with the Merger (the “Treeline Converting Warrants”) and that is outstanding immediately prior to the Effective Time will, by virtue of the Merger, be cancelled and extinguished and converted into the right to receive, for each share of Treeline Common Stock that would be received upon the net-exercise of such Treeline Converting Warrant in accordance with its terms, a number of shares of Standard BioTools Common Stock equal to the Exchange Ratio and (ii) each Treeline Warrant that is not a Treeline Converting Warrant and that is outstanding immediately prior to the Effective Time will, by virtue of the Merger, be assumed by Standard BioTools. Each such Treeline Warrant so assumed by Standard BioTools will continue to have, and be subject to, the same terms and conditions applicable to such Treeline Warrant immediately prior to the Effective Time, except that (a) such Treeline Warrant will be exercisable for that number of shares of Standard BioTools Common Stock equal to the number of shares of Treeline Common Stock subject to such Treeline Warrant immediately prior to the Effective Time multiplied by the Exchange Ratio and rounded down to the next nearest share of Standard BioTools Common Stock and (b) the warrant price per share will be the warrant price per share in effect for such Treeline Warrant immediately prior to the Effective Time divided by the Exchange Ratio and rounded up to the nearest thousandth of a cent.

Each share of Standard BioTools Common Stock issued and outstanding at the time of the Merger will remain issued and outstanding and, subject to the Reverse Stock Split, will be unaffected by the Merger. In addition, prior to the Effective Time, Standard BioTools expects to declare a dividend to Standard BioTools stockholders as of the close of business on the last business day prior to the day on which the Effective Time occurs in the form of one contingent value right (each, a “CVR”) for each outstanding share of Standard BioTools Common Stock held by such stockholder on such date. The payment date for such dividend will be three business days after the Effective Time. The CVRs will be issued pursuant to the terms of a Contingent Value Rights Agreement to be entered into between Standard BioTools and a rights agent (the “CVR Agreement”) (described in more detail in the section titled “The Merger — CVR Agreement” beginning on page 212 of the accompanying proxy statement/prospectus). Pursuant to the CVR Agreement, the holder of each CVR will be entitled to receive a payment for each 12-month CVR payment period during the five-year term of the CVR Agreement, consisting of a number of shares of the combined company’s common stock (with fractional shares settled in cash) equal to such holder’s pro rata portion of the aggregate net proceeds received by the combined company during such 12-month CVR payment period from the following sources, in each case less certain permitted deductions: (i) proceeds from any sale, disposition, or other monetization of Standard BioTools’ mass cytometry and microfluidics businesses (the “Legacy Businesses”), including any cash proceeds received in connection with the Mass Cytometry Divestiture during the five-year term of the CVRs; (ii) proceeds from convertible notes or other investments held by Standard BioTools as of the date of the Closing (the “Closing Date”); (iii) earnout, milestone, royalty or other similar contingent payments due to Standard BioTools under contracts in effect as of the Closing Date; and (iv) any surplus in Parent Net Cash delivered at Closing as finally determined under the Merger Agreement. The maximum number of shares of common stock of the combined company which may be issued pursuant to the CVR Agreement is 76,000,000. There can be no assurance that any payments will be made on the CVRs.

Because the Merger is accounted for as a reverse recapitalization with Treeline as the accounting acquirer, the historical financial statements of Treeline will become the historical financial statements of the Combined Company in all future public filings following the Merger. The historical financial statements of Standard BioTools for periods prior to the Merger will not be presented as the financial statements of the Combined Company in future public filings following the Merger.

Under the Merger Agreement, Standard BioTools must use its commercially reasonable efforts to effect the sale, license, transfer, disposition, divestiture or other monetization of the Legacy Businesses. If Standard BioTools has not entered into a definitive agreement for the disposition of any portion of the Legacy Businesses on or before the date the registration statement on Form S-4 of which the accompanying proxy statement/prospectus forms a part is declared effective under the Securities Act of 1933, as amended (the “Securities Act”), Standard BioTools is required to commence mutually agreed wind-down activities with respect to that portion of the Legacy Businesses. On July 28, 2026, Standard BioTools entered into a Share and Asset Purchase Agreement (the “Mass Cytometry Purchase Agreement”) with Multiplex Bio Inc., a Delaware corporation (“Multiplex Bio”), pursuant to which and on the terms and subject to the conditions set forth therein, Multiplex Bio will acquire the portion of the Legacy Businesses comprised of Standard BioTools’ mass cytometry business (the “Mass Cytometry Divestiture”) (described in more detail in the section titled “The Mass Cytometry Divestiture” beginning on page 248 of the accompanying proxy statement/prospectus). It is a condition to the consummation of the Mass Cytometry Divestiture that the Merger and the Merger Transactions be consummated prior to or substantially concurrently with the consummation of the Mass Cytometry Divestiture.

The accompanying proxy statement/prospectus also relates to the offer and sale, from time to time, of shares of Standard BioTools Common Stock by certain stockholders of Treeline who will receive shares of Standard BioTools Common Stock in the Merger (the “Selling Securityholders”). Standard BioTools will not receive any of the proceeds from any sale of shares of Standard BioTools Common Stock by the Selling Securityholders. See “Selling Securityholders” and “Plan of Distribution” in the resale prospectus also included in the registration statement on Form S-4 of which the accompanying proxy statement/prospectus forms a part.

Standard BioTools and Treeline expect the board of directors of the combined company will consist of 12 members, with 10 members designated by Treeline and two members designated by Standard BioTools. The parties also expect that, immediately after the Effective Time, Joshua Bilenker, currently the chief executive officer and co-founder of Treeline, will be appointed as Chief Executive Officer of the combined company, Jeffrey Engelman, currently the chief scientific officer and co-founder of Treeline, will be appointed as Chief Scientific Officer of the combined company, and Spencer Smith, currently the chief financial officer of Treeline, will be appointed as Chief Financial Officer of the combined company.

Standard BioTools Common Stock is currently listed on The Nasdaq Global Select Market under the symbol “LAB.” After completion of the Merger, Standard BioTools will be renamed “Treeline Biosciences Holdings, Inc.,” and it is expected that the common stock of the combined company will trade on The Nasdaq Stock Market LLC (“Nasdaq”) under the symbol “TRLN.” It is a condition to the consummation of the Merger that existing shares of Standard BioTools Common Stock are listed on Nasdaq as of the Closing Date and that the shares of Standard BioTools Common Stock issuable in connection with the Merger have been approved for listing on Nasdaq, subject to official notice of issuance, but there can be no assurance that such listing condition will be met.

We have scheduled a special meeting of the stockholders of Standard BioTools (the “Special Meeting”), to be held entirely virtually on     , 2026, at which the stockholders of Standard BioTools will be asked to vote on the Share Issuance Proposal, the Charter Amendment Proposal, the Post-Closing Equity Incentive Plan Proposal, the Post-Closing ESPP Proposal, the Advisory Compensation Proposal, the Mass Cytometry Divestiture Proposal and the Adjournment Proposal (each as defined herein). We cannot consummate the Merger and the other Merger Transactions unless the stockholders of Standard BioTools approve the Share Issuance Proposal and the Charter Amendment Proposal as described herein. We cannot consummate the Mass Cytometry Divestiture unless the stockholders of Standard BioTools approve the Mass Cytometry Divestiture Proposal, the Share Issuance Proposal and the Charter Amendment Proposal as described herein. Approval of the Post-Closing Equity Incentive Plan Proposal, the Post-Closing ESPP Proposal, the Advisory Compensation Proposal, the Mass Cytometry Divestiture Proposal and the Adjournment Proposal are not conditions to completion of the Merger. Your vote is very important, regardless of the number of shares of Standard BioTools Common Stock that you own. Whether or not you expect to attend the Special Meeting, please submit a proxy to vote your shares as promptly as possible so that your shares may be represented and voted at the Special Meeting.

As described in the accompanying proxy statement/prospectus, concurrently with the execution of the Merger Agreement, certain stockholders of Standard BioTools (including its directors and certain officers), collectively holding approximately 39% of the outstanding shares of Standard BioTools Common Stock, entered into voting agreements with Standard BioTools, Treeline and Merger Sub (the “Voting Agreements”) (described in more detail in the section titled “The Special Meeting — Voting Agreements” beginning on page 121 of the accompanying proxy statement/prospectus) pursuant to which they have agreed to vote all of their shares of Standard BioTools Common Stock in favor of the Share Issuance Proposal, the Charter Amendment Proposal, the Post-Closing Equity Incentive Plan Proposal and the Post-Closing ESPP Proposal, subject to the terms of the Voting Agreements, including a reduction in

the number of shares subject to the voting requirements for certain stockholders in the event of a change in the recommendation of the Special Committee (as defined below) in favor of the Merger Transactions such that the aggregate number of outstanding shares of Standard BioTools Common Stock subject to the voting requirements in the Voting Agreements is reduced to approximately 30% of the outstanding shares of Standard BioTools Common Stock.

The Standard BioTools Board of Directors (the “Standard BioTools Board”) established a special committee of the Standard BioTools Board consisting solely of “disinterested directors” (as defined in Section 144(e)(4) of the Delaware General Corporation Law (the “DGCL”)) (the “Special Committee”) and delegated to the Special Committee the full power and authority of the Standard BioTools Board, to the maximum extent permitted by applicable law, to (i) explore, consider, evaluate, review, negotiate and approve or reject the Merger Transactions and, if Standard BioTools Board approval of the Merger Transactions is required under the DGCL, recommend to the Standard BioTools Board for approval or rejection of the Merger Transactions and (ii) determine whether the Merger Transactions are advisable, fair to and in the best interests of Standard BioTools and its stockholders. After due consideration and discussion of the factors that the Special Committee deemed relevant, the Special Committee unanimously (i) determined that the Merger Transactions are advisable, fair to and in the best interests of Standard BioTools and its stockholders, (ii) approved and declared advisable the Merger Agreement and the Merger Transactions and recommended that the Standard BioTools Board approve and declare advisable the Merger Transactions and (iii) recommended that the Standard BioTools Board resolve to recommend the approval of the issuance of Standard BioTools Common Stock pursuant to the Merger Agreement (the “Share Issuance”) and the Charter Amendment by Standard BioTools’ stockholders. The Special Committee also unanimously (i) determined that the Mass Cytometry Divestiture is advisable, fair to and in the best interests of Standard BioTools and its stockholders, (ii) approved and declared advisable the Mass Cytometry Purchase Agreement and the Mass Cytometry Divestiture and recommended that the Standard BioTools Board approve and declare advisable the Mass Cytometry Purchase Agreement and the Mass Cytometry Divestiture and (iii) recommended that the Standard BioTools Board resolve to recommend the approval of the Mass Cytometry Divestiture by Standard BioTools’ stockholders.

Acting upon the recommendation of the Special Committee, the Standard BioTools Board has (i) determined that the Merger Transactions are advisable, fair to and in the best interests of Standard BioTools and its stockholders, (ii) approved and declared advisable the Merger Agreement and the Merger Transactions and (iii) resolved to recommend the approval of the Share Issuance and the Charter Amendment by Standard BioTools’ stockholders. The Standard BioTools Board has also unanimously (i) determined that the Mass Cytometry Divestiture is advisable, fair to and in the best interests of Standard BioTools and its stockholders, (ii) approved and declared advisable the Mass Cytometry Divestiture Purchase Agreement and the Mass Cytometry Divestiture and (iii) resolved to recommend the approval of the Mass Cytometry Divestiture by Standard BioTools’ stockholders. In addition, the Standard BioTools Board resolved to recommend the approval of the Post-Closing Equity Incentive Plan, the Post-Closing ESPP, on a nonbinding, advisory basis, the Transaction-Related Compensation (each as defined in the accompanying proxy statement/prospectus) by Standard BioTools’ stockholders and the adjournment of the Special Meeting, if necessary or appropriate to solicit additional proxies. The Standard BioTools Board recommends that Standard BioTools stockholders vote “FOR” each of the proposals to be considered at the Special Meeting and described in the accompanying proxy statement/prospectus.

The Merger Agreement and the Merger Transactions have also been approved by Treeline’s board of directors. In addition, after execution of the Merger Agreement, on June 6, 2026, Treeline stockholders comprising the required majorities under Treeline’s organizational documents delivered their written consent adopting the Merger Agreement and approving the Merger Transactions.

The obligations of Treeline and Standard BioTools to consummate the Merger are subject to the satisfaction or waiver (to the extent permitted by applicable law) of several conditions set forth in the Merger Agreement, including receipt of Standard BioTools stockholder approval for the required proposals described in the accompanying proxy statement/prospectus. The obligations of Multiplex Bio and Standard BioTools to consummate the Mass Cytometry Divestiture are subject to the satisfaction or waiver (to the extent permitted by applicable law) of several conditions set forth in the Mass Cytometry Divestiture Purchase Agreement, including receipt of Standard BioTools stockholder approval for the Mass Cytometry Divestiture Proposal described in the accompanying proxy statement/prospectus and that the Merger and the Merger Transactions be consummated prior to or substantially concurrently with the consummation of the Mass Cytometry Divestiture. The accompanying proxy statement/prospectus contains detailed information about Treeline, Multiplex Bio, Standard BioTools, the Special Meeting, the Merger Agreement, the Merger Transactions (including the Merger), the Mass Cytometry Divestiture Purchase Agreement, the Mass Cytometry Divestiture and the other business to be considered by the Standard BioTools stockholders at the Special Meeting. Standard BioTools encourages you to read the accompanying proxy statement/prospectus carefully. In particular, you should read the “Risk Factors” section beginning on page 42 of the accompanying proxy statement/prospectus for a discussion of the risks you should consider in evaluating the Merger Transactions and how they will affect you.

On behalf of the Standard BioTools Board, thank you for your consideration and continued support.

Neither the United States Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of the Merger, the securities to be issued in connection with the Merger or any other transaction described in the accompanying proxy statement/prospectus or passed upon the adequacy or accuracy of the disclosure in the accompanying proxy statement/prospectus. Any representation to the contrary is a criminal offense.

The accompanying proxy statement/prospectus is dated       , 2026 and is first being mailed to the Standard BioTools stockholders on or about       , 2026.

The accompanying proxy statement/prospectus incorporates by reference important business and financial information about Standard BioTools from other documents that are not included in or delivered with the accompanying proxy statement/prospectus. This information is available to you without charge upon your request. You can obtain the documents incorporated by reference into the accompanying proxy statement/prospectus by requesting them in writing or by telephone from Standard BioTools at the following addresses and telephone numbers:

Standard BioTools stockholders may also consult the website of Standard BioTools for more information concerning the Merger and the other transactions described in the accompanying proxy statement/prospectus. The website of Standard BioTools is www.standardbio.com. Information included on the website of Standard BioTools is not incorporated by reference into the accompanying proxy statement/prospectus.

If you would like to request any documents, you must do so by    , 2026, in order to receive them before the Special Meeting.

For a more detailed description of the information incorporated by reference in the accompanying proxy statement/prospectus and how you may obtain it, see “Where You Can Find More Information” beginning on page 398 of the accompanying proxy statement/prospectus.

We cordially invite you to attend a special meeting of the stockholders of Standard BioTools Inc., a Delaware corporation (“Standard BioTools”), being held in connection with a proposed all-stock business combination with Treeline Biosciences, Inc., a Delaware corporation (“Treeline”). On June 6, 2026, Standard BioTools, Treeline and Siri Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of Standard BioTools (“Merger Sub”), entered into an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”), pursuant to which Merger Sub will merge with and into Treeline, with Treeline surviving as a wholly owned subsidiary of Standard BioTools (the “Merger” and, together with the other transactions contemplated by the Merger Agreement, the “Merger Transactions”), and Standard BioTools will be renamed “Treeline Biosciences Holdings, Inc.” Additionally, on July 28, 2026, Standard BioTools entered into a Share and Asset Purchase Agreement (the “Mass Cytometry Purchase Agreement”) with Multiplex Bio Inc., a Delaware corporation (“Multiplex Bio”), pursuant to which and on the terms and subject to the conditions set forth therein, Multiplex Bio will acquire Standard BioTools’ mass cytometry business (the “Mass Cytometry Divestiture”).

The special meeting will take place exclusively online via webcast on     , 2026, at     (the “Special Meeting”). The Special Meeting can be accessed by visiting www.virtualshareholdermeeting.com/LAB2026SM, where you will be able to listen to the meeting live, submit questions, and vote online. At the Special Meeting, you will be asked to consider and vote upon the following proposals:

You can vote “FOR,” “AGAINST” or “ABSTAIN” on each of the Proposals. The approval by Standard BioTools stockholders of the Share Issuance Proposal and the Charter Amendment Proposal is a condition to the consummation of the Merger and the other Merger Transactions. Additionally, because the consummation of the Merger and the other Merger Transactions is a condition to the consummation of the Mass Cytometry Divestiture, the approval by Standard BioTools stockholders of the Share Issuance Proposal and the Charter Amendment Proposal is a condition to the consummation of the Mass Cytometry Divestiture. If the Share Issuance Proposal and the Charter Amendment Proposal are not approved, neither the Merger and the other Merger Transactions nor the Mass Cytometry Divestiture will be consummated. Approval of the Post-Closing Equity Incentive Plan Proposal, the Post-Closing ESPP Proposal, the Advisory Compensation Proposal, the Mass Cytometry Divestiture Proposal and the Adjournment Proposal is not required for the consummation of the Merger and the other Merger Transactions. The Standard BioTools Board of Directors (the “Standard BioTools Board”) is not aware of any other business to be acted upon at the Special Meeting.

The Proposals are described in more detail in the accompanying proxy statement/prospectus, which you should read carefully in its entirety.

The Standard BioTools Board has set     , 2026 as the record date for the Special Meeting. Only holders of record of Standard BioTools Common Stock as of 5:00 p.m. U.S. Eastern Time on     , 2026 will be entitled to notice of and to vote at the Special Meeting and any adjournments thereof. Any stockholder entitled to attend and vote at the Special Meeting is entitled to appoint a proxy to attend and vote on such stockholder’s behalf. Such proxy need not be a holder of Standard BioTools Common Stock.

To be approved, (1) the Share Issuance Proposal, the Post-Closing Equity Incentive Plan Proposal, the Post-Closing ESPP Proposal, the Advisory Compensation Proposal and the Adjournment Proposal require the affirmative vote of a majority of the voting power of the shares of Standard BioTools’ capital stock present in person or represented by proxy at the Special Meeting and entitled to vote on such Proposal at the Special Meeting, (2) the Charter Amendment Proposal requires the affirmative vote of the holders of Standard BioTools’ capital stock entitled to vote thereon, voting as a single class, by a majority of the votes cast for or against such Proposal at the Special Meeting and (3) the Mass Cytometry Divestiture Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of Standard BioTools’ capital stock entitled to vote on such Proposal at the Special Meeting.

The failure of any stockholder of record of Standard BioTools to submit a signed proxy card, grant a proxy electronically over the Internet or by telephone or to vote virtually by ballot at the Special Meeting will have no effect on the outcome of the vote for the Proposals (other than the Mass Cytometry Divestiture Proposal) and will have the same effect as a vote “AGAINST” the Mass Cytometry Divestiture Proposal. Abstentions will have the same effect as a vote “AGAINST” the Proposals (other than the Charter Amendment Proposal) and will have no effect on the outcome of the vote for the Charter Amendment Proposal. If you hold your shares of Standard BioTools’ capital stock in “street name” through a bank, broker or other nominee and you do not instruct your bank,

broker or other nominee on how to vote your shares, your bank, broker or other nominee will not be permitted to vote your shares on any of the Proposals, which will have no effect on the outcome of the vote for the Proposals (other than the Mass Cytometry Divestiture Proposal) and will have the same effect as a vote “AGAINST” the Mass Cytometry Divestiture Proposal.

Your vote is very important. Whether or not you expect to attend the Special Meeting, we urge you to submit your proxy with respect to your shares of Standard BioTools Common Stock as promptly as possible by: (1) accessing the Internet website specified on your proxy card; (2) calling the toll-free number specified on your proxy card; or (3) signing and returning the enclosed proxy card in the postage-paid envelope provided, to ensure that your shares of Standard BioTools Common Stock are represented and voted at the Special Meeting. Submitting a proxy now will not prevent you from being able to vote in person at the Special Meeting. If your shares of Standard BioTools Common Stock are held in “street name” in the name of a bank, broker or other nominee, please follow the instructions on the voting instruction card furnished by such bank, broker or other nominee.

The Special Committee of the Standard BioTools Board has unanimously (i) determined that the Merger Transactions and the Mass Cytometry Divestiture are advisable, fair to and in the best interests of Standard BioTools and its stockholders, (ii) approved and declared advisable the Merger Agreement, the Merger Transactions, the Mass Cytometry Purchase Agreement and the Mass Cytometry Divestiture and recommended that the Standard BioTools Board approve and declare advisable the Merger Transactions and the Mass Cytometry Divestiture and (iii) recommended that the Standard BioTools Board resolve to recommend the approval of the Share Issuance (as defined in the accompanying proxy statement/prospectus), the Charter Amendment (as defined in the accompanying proxy statement/prospectus) and the Mass Cytometry Divestiture by Standard BioTools’ stockholders.

In addition, the Standard BioTools Board has (i) determined that the Merger Transactions and the Mass Cytometry Divestiture are advisable, fair to and in the best interests of Standard BioTools and its stockholders, (ii) approved and declared advisable the Merger Agreement, the Merger Transactions, the Mass Cytometry Purchase Agreement the Mass Cytometry Divestiture and (iii) resolved to recommend the approval of the Share Issuance, the Charter Amendment, the Post-Closing Equity Incentive Plan, the Post-Closing ESPP, the Transaction-Related Compensation (on a nonbinding, advisory basis), the Mass Cytometry Divestiture and the adjournment of the Special Meeting, if necessary or appropriate to solicit additional proxies (in each case, as defined in the accompanying proxy statement/prospectus) by Standard BioTools’ stockholders. The Standard BioTools Board recommends that you vote “FOR” each Proposal.

WHETHER OR NOT YOU EXPECT TO ATTEND THE SPECIAL MEETING, WE URGE YOU TO SUBMIT YOUR PROXY AS PROMPTLY AS POSSIBLE (1) VIA THE INTERNET, (2) BY TELEPHONE OR (3) BY MARKING, SIGNING AND DATING THE ENCLOSED STANDARD BIOTOOLS PROXY CARD AND RETURNING IT IN THE POSTAGE-PAID ENVELOPE PROVIDED. IF YOU ATTEND THE SPECIAL MEETING AND WISH TO VOTE YOUR SHARES OF STANDARD BIOTOOLS COMMON STOCK, YOU MAY DO SO AT ANY TIME PRIOR TO THE CLOSING OF THE POLLS AT THE SPECIAL MEETING. You may revoke your proxy or change your vote at any time before the polls close at the Special Meeting. If your shares of Standard BioTools Common Stock are held in “street name” in the name of a bank, broker or other nominee holder of record, please follow the instructions on the voting instruction card furnished to you by such record holder.

We urge you to read the accompanying proxy statement/prospectus, including all documents incorporated by reference into the accompanying proxy statement/prospectus, and its annexes and exhibits carefully and in their entirety. If you have any questions concerning the Merger Agreement, the Merger Transactions, the Mass Cytometry Purchase Agreement, the Mass Cytometry Divestiture, the Proposals, the Special Meeting or the accompanying proxy statement/prospectus, would like additional copies of the accompanying proxy statement/prospectus or need help voting your shares of Standard BioTools, please contact:

The following are answers to some questions that you, as a stockholder of Standard BioTools Inc., a Delaware corporation (“Standard BioTools,” “we” or “our”), may have regarding the proposed business combination (the “Merger” and, together with the other transactions contemplated by the Merger Agreement, as defined below, the “Merger Transactions”) between Standard BioTools and Treeline Biosciences, Inc., a Delaware corporation (“Treeline”), the proposed divestiture of Standard BioTools’ mass cytometry business (the “Mass Cytometry Divestiture”) and the proposals to be considered at the special meeting of Standard BioTools stockholders (the “Special Meeting”). This section does not provide all the information that might be important to you with respect to the proposed Merger or the proposed Mass Cytometry Divestiture. Standard BioTools urges you to carefully read the remainder of this proxy statement/prospectus, including the annexes. The information in this proxy statement/prospectus, including the information contained in this “Questions and Answers About the Merger and the Mass Cytometry Divestiture,” does not give effect to the Reverse Stock Split (as defined below).

The selected historical condensed consolidated statements of operations data of Treeline for the six months ended June 30, 2026 and 2025 and the condensed consolidated balance sheet data as of June 30, 2026 are derived from Treeline’s unaudited condensed consolidated interim financial statements included elsewhere in this proxy statement/prospectus. The selected historical consolidated statements of operations data of Treeline for the years ended December 31, 2025 and 2024 and the selected historical consolidated balance sheet data as of December 31, 2025 and 2024 are derived from Treeline’s audited consolidated financial statements included elsewhere in this proxy statement/prospectus. The unaudited condensed consolidated interim financial data set forth below have been prepared on the same basis as Treeline’s audited consolidated financial statements and, in the opinion of Treeline’s management, include all normal and recurring adjustments, that are necessary for the fair statement of such data.

Treeline’s historical results are not necessarily indicative of the results that may be expected in the future and Treeline’s results for the six months ended June 30, 2026 are not necessarily indicative of the results that may be expected for the full year ending December 31, 2026 or any other period. You should read the following selected historical consolidated financial data together with the sections entitled “Treeline Management’s Discussion and Analysis of Financial Condition and Results of Operations” and Treeline’s audited consolidated financial statements and accompanying notes and unaudited condensed consolidated interim financial statements and accompanying notes included elsewhere in this proxy statement/prospectus.

The following selected unaudited pro forma condensed combined financial data (the “selected pro forma data”) give effect to (i) the Merger, which is expected to be accounted for as a reverse recapitalization under U.S. GAAP, (ii) the Mass Cytometry Divestiture, (iii) the probable wind-down and / or sale of Standard BioTools’ remaining Legacy Businesses, including the transfer of certain of Standard BioTools operating assets and liabilities to one or more third-parties, or other wind-down activities for Standard BioTools remaining operating assets and liabilities, (iv) the automatic conversion of Treeline redeemable convertible preferred stock, (v) the Reverse Stock Split, and (vi) other Merger related items. The selected unaudited pro forma condensed combined statements of operations for the year ended December 31, 2025 and the six months ended June 30, 2026 give effect to the Merger as if the Merger had occurred on January 1, 2025. The selected unaudited pro forma condensed combined balance sheet as of June 30, 2026 gives effect to the Merger as if the Merger had occurred on June 30, 2026, assuming that each outstanding share of Treeline Capital Stock, each Treeline Option and each outstanding Treeline Warrant that is not a Treeline Converting Warrant had become Standard BioTools Common Stock, Standard BioTools Options or a warrant to purchase Standard BioTools Common Stock, respectively, based on an estimated Exchange Ratio of 11.6997 (based on Standard BioTools’ and Treeline’s capitalization as of June 3, 2026 and May 28, 2026, respectively, and taking into account Standard BioTools’ estimated cash position as of the Closing and excluding the effect of the Reverse Stock Split). In addition, each Treeline Converting Warrant will be converted into a number of shares of Standard BioTools Common Stock calculated by applying the estimated Exchange Ratio to each share of Treeline Common Stock that would have been received upon net-exercise of such warrant.

The selected pro forma data have been derived from, and should be read in conjunction with, the more detailed unaudited pro forma condensed combined financial information of Standard BioTools following the Merger appearing elsewhere in this proxy statement/prospectus and the accompanying notes to the unaudited pro forma condensed combined financial information. See “Unaudited Pro Forma Condensed Combined Financial Information” beginning on page 352 of this proxy statement/prospectus.

In addition, the selected pro forma data were based on, and should be read in conjunction with, the following historical consolidated financial statements and accompanying notes:

The pro forma financial information does not include any adjustments for the disposition of SomaLogic, Inc. by Standard BioTools. On January 30, 2026, Standard BioTools completed the sale of all of the equity interests of SomaLogic, Inc., Sengenics Corporation LLC, and Sengenics Corporation Pte Ltd (collectively, the “SomaLogic Entities”) to Illumina, Inc. (“Illumina”) pursuant to the Stock Purchase Agreement (the “Purchase Agreement”), dated June 22, 2025, by and between Standard BioTools and Illumina. The SomaLogic Entities comprised Standard BioTools’ SomaScan® Business, including its SomaScan assay platform and related products and services. Standard BioTools determined that the SomaLogic Entities met the held-for-sale criteria under ASC 360, Property, Plant, and Equipment, and the discontinued operations criteria under ASC 205, Presentation of Financial Statements, during the second quarter of 2025. Accordingly, during the year ended December 31, 2025, Standard BioTools presented the SomaLogic Entities as held-for-sale and as discontinued operations for all periods presented. No pro forma adjustments to the statement of operations for the year ended December 31, 2025 or the six months ended June 30, 2026 are necessary, as those periods already reflect the full effect of removing the SomaLogic Entities from the continued operations presentation. Similarly, no pro forma adjustments to the balance sheet as of June 30, 2026 are necessary, as the balance sheet as of such date already gives effect to the disposition of the SomaLogic Entities.

The pro forma adjustments give effect to the disposition of the Legacy Businesses and the related assets and activities, including the Mass Cytometry Divestiture. On July 28, 2026, Standard BioTools entered into the Mass Cytometry Purchase Agreement with Multiplex Bio, pursuant to which and on the terms and subject to the

conditions set forth therein, Multiplex Bio will acquire the portion of the Legacy Businesses comprised of Standard BioTools’ mass cytometry business. Standard BioTools expects that, subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement and the Mass Cytometry Purchase Agreement, the Mass Cytometry Divestiture will be consummated substantially concurrently with the Merger and the other Merger Transactions. As of the filing of the registration statement on Form S-4 of which this proxy statement/prospectus forms a part, a definitive asset purchase agreement for the sale of Standard BioTools’ microfluidics business has not yet been executed. However, since Standard BioTools expects the sale of the microfluidics business to be completed prior to or concurrently with the Closing and the Mass Cytometry Divestiture, the selected pro forma data have been prepared on that basis. Although an asset purchase agreement has not yet been executed and wind-down activities have not been completed for the microfluidics business, all existing business activities of Standard BioTools are expected to be disposed prior to the Closing. Therefore, the pro forma adjustments give effect to the disposition of the Legacy Businesses and the related assets and activities, which are considered probable, as if it had occurred. Any proceeds obtained from the sale of the Legacy Businesses are subject to the CVR. Net proceeds from the sales of the Legacy Businesses would be fully offset by a CVR liability, which has not been reflected within the selected pro forma data due to the uncertainty of expected net proceeds.

The selected pro forma data have been presented for informational purposes only. The selected pro forma data do not purport to represent the actual results of operations that Standard BioTools and Treeline would have achieved had the companies been combined during the periods presented in the selected financial data and is not intended to project the future results of operations that Standard BioTools may achieve after the Merger is consummated. The selected pro forma data do not reflect any cost savings that may be realized as a result of the Merger and also do not reflect any restructuring or integration-related costs to achieve those potential cost savings. Amounts below are presented in thousands, except per share amounts.

Standard BioTools Common Stock is currently listed on The Nasdaq Global Select Market under the symbol “LAB.” The closing price of the Standard BioTools Common Stock on June 5, 2026, the last day of trading prior to the announcement of the Merger, as reported on Nasdaq, was $1.15 per share. The closing price of the Standard BioTools Common Stock on    , 2026, the last practicable date before the date of this proxy statement/prospectus, as reported on Nasdaq, was $   per share.

Because the market price of the Standard BioTools Common Stock is subject to fluctuation, the market value of the shares of the Standard BioTools Common Stock that the Treeline stockholders will be entitled to receive in the Merger may increase or decrease. The market price of Standard BioTools Common Stock has fluctuated since the date of the announcement of the Merger Agreement and will continue to fluctuate from the date of this proxy statement/prospectus to the date of the Special Meeting and the date the Merger is consummated and thereafter. No assurance can be given concerning the market price of Standard BioTools Common Stock before consummation of the Merger or the market price of Standard BioTools Common Stock after consummation of the Merger.

Standard BioTools anticipates that the common stock of the combined company will be listed on Nasdaq following the Closing under the trading symbol “TRLN.” It is a condition to the consummation of the Merger that existing shares of Standard BioTools Common Stock are listed on Nasdaq as of the Closing Date and that the shares of Standard BioTools Common Stock issuable in connection with the Merger have been approved for listing on Nasdaq, subject to official notice of issuance, but there can be no assurance such listing condition will be met. If such listing condition is not met, the Merger will not be consummated unless the condition is waived.

Treeline is a private company and shares of Treeline Capital Stock are not publicly traded.

As of 5:00 p.m. U.S. Eastern Time on the Record Date,    shares of Standard BioTools Common Stock, held by    holders of record, were outstanding and entitled to vote at the Special Meeting.

Standard BioTools has never declared or paid any cash dividends on Standard BioTools Common Stock. Any determination to pay cash dividends subsequent to the Merger will be at the discretion of the combined company’s then-current board of directors and will depend upon a number of factors, including the combined company’s results of operations, financial condition, future prospects, contractual restrictions, restrictions imposed by applicable law and other factors the then-current board of directors deems relevant.

Prior to the Effective Time, Standard BioTools expects to declare a dividend to Standard BioTools stockholders as of the close of business on the last business day prior to the day on which the Effective Time occurs in the form of one CVR for each outstanding share of Standard BioTools Common Stock held by such stockholder on such date. The payment date for such dividend will be three business days after the Effective Time. The CVRs will be issued pursuant to the terms of the CVR Agreement. See “The Merger — CVR Agreement.”

Treeline has never paid or declared any cash dividends on Treeline Capital Stock and does not anticipate paying any cash dividends on the Treeline Capital Stock in the foreseeable future.

In addition to the other information contained in or incorporated by reference into this proxy statement/prospectus, including the matters addressed under “Cautionary Statement Regarding Forward-Looking Statements” in this proxy statement/prospectus, Standard BioTools stockholders should carefully consider the following risks in deciding whether to vote for the approval of the Standard BioTools Proposals. Descriptions of other risks can be found in the Annual Report for Standard BioTools on Form 10-K for the year ended December 31, 2025, the Quarterly Reports for Standard BioTools on Form 10-Q for the quarters ended March 31, 2026 and June 30, 2026, and any amendments thereto, as such risks may be updated or supplemented in Standard BioTools’ subsequently filed Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and other filings with the SEC from time to time, which are incorporated by reference into this proxy statement/prospectus. You should read carefully this entire proxy statement/prospectus and its annexes and exhibits and the other documents incorporated by reference into this proxy statement/prospectus. See also “Incorporation of Certain Documents by Reference” and “Where You Can Find More Information” beginning on pages 397 and 398, respectively, of this proxy statement/prospectus.

There can be no assurance that the Merger will be successfully consummated or lead to increased stockholder value. The completion of the Merger is dependent on a number of factors that may be beyond the control of Standard BioTools and Treeline, including, among other things, market conditions, regulatory approval and stockholder approval. Any failure to consummate the Merger would have a material adverse effect on Standard BioTools’ and Treeline’s businesses and could significantly impair Standard BioTools’ and Treeline’s ability to enter into alternative strategic transactions.

The process of completing the Merger is costly, time-consuming and complex. Standard BioTools and Treeline have incurred, and may in the future incur, significant costs related to the Merger, including legal and accounting fees and expenses and other related charges, which have been and will be incurred regardless of whether the Merger is completed. Standard BioTools and Treeline may also incur additional unanticipated expenses in connection with the Merger. These expenses will decrease the remaining cash available for use in Standard BioTools’ and Treeline’s businesses. Also, the Merger could have a variety of negative consequences, or yield unexpected results, that adversely affect Standard BioTools’ and Treeline’s businesses and decrease the remaining cash available for use in the combined company’s future business.

If the Merger is not completed in a timely fashion, Standard BioTools and Treeline may experience reputational harm and the value of the Standard BioTools Common Stock and the Treeline Common Stock may be adversely impacted. In addition, speculation regarding the completion of the Merger and perceived uncertainties related to the future of Standard BioTools could cause Standard BioTools’ stock price to fluctuate significantly. Also, if the Merger Agreement is terminated and the Standard BioTools Board determines to seek another business combination, there can be no assurance that Standard BioTools will be able to find another third party to transact a business combination with, yielding comparable or greater benefits.

The Merger Agreement contains a number of conditions that must be satisfied or waived (to the extent permitted by applicable law) in order to consummate the Merger, some of which are not within Standard BioTools’ control. These conditions include, among others:

Any failure to satisfy or, to the extent permitted by applicable law, waive these required closing conditions may prevent, delay or otherwise materially adversely affect the consummation of the Merger. Standard BioTools cannot predict with certainty whether or when any of the required conditions will be satisfied or, to the extent permitted by applicable law, waived, and cannot assure you that Standard BioTools will be able to successfully consummate the Merger as currently contemplated under the Merger Agreement or at all. For additional information regarding the conditions to the Merger, see “The Merger Agreement — Conditions to the Completion of the Merger” beginning on page 226 of this proxy statement/prospectus.

In addition, the Merger might not be consummated because Treeline or Standard BioTools may elect to terminate the Merger Agreement in certain circumstances. Upon termination of the Merger Agreement under specified circumstances, including if Treeline terminates the Merger Agreement due to a change in the Standard BioTools Board recommendation in favor of the Merger Transactions, Standard BioTools will be required to make a payment to Treeline equal to $16.1 million in cash. In addition, Standard BioTools will be required to reimburse Treeline’s reasonable out-of-pocket fees in connection with the Merger Transactions up to a maximum of $5.0 million if the Merger Agreement is terminated due to a failure to obtain the required approval of Standard BioTools stockholders. See “The Merger Agreement — Termination” beginning on page 243 of this proxy statement/prospectus.

In connection with the Closing, each share of Treeline Capital Stock (other than treasury shares and dissenting shares) issued and outstanding immediately prior to the Effective Time will be converted into the right to receive a number of shares of Standard BioTools Common Stock equal to the Exchange Ratio, provided that the number of shares of Standard BioTools Common Stock which each holder of Treeline Capital Stock is entitled to receive will be rounded down to the nearest whole share and computed after aggregating all shares of Treeline Capital Stock held by such holder, with no cash payable in lieu of fractional shares.

The Exchange Ratio will not be adjusted in the event of any change in the market price of Standard BioTools Common Stock and, as a result, prior to the Effective Time, Standard BioTools stockholders and Treeline stockholders cannot be sure of the value of the Standard BioTools Common Stock to be issued in connection with the Merger. Changes in the Standard BioTools stock price can result from a variety of factors, including general market, industry and economic conditions, changes in the respective businesses, operations and prospects of Treeline and Standard BioTools, regulatory considerations, results of the Special Meeting, announcements with respect to the Merger or any of the foregoing, and other factors beyond the control of Treeline or Standard BioTools.

The exact dollar value of the Standard BioTools Common Stock that the Standard BioTools stockholders and the Treeline stockholders will hold upon consummation of the Merger will not be known at the time of the Special Meeting and may be greater than, the same as or less than the current market price of the Standard BioTools Common Stock at the time of the Special Meeting. The market price of Standard BioTools Common Stock is subject to general price fluctuations in the market for publicly traded equity securities and has experienced volatility in the past and may vary significantly after the date of the Special Meeting. As a result of these fluctuations, the value of the Merger consideration will also vary. For example, based on the range of closing prices of Standard BioTools Common Stock during the period from June 5, 2026, the last trading day before public announcement of the Merger, through     , the latest practicable trading date before the filing of this proxy statement/prospectus and in each case, taking into account Standard BioTools’ current cash position and excluding the effect of the Reverse Stock Split, the Exchange Ratio represented a value ranging from a low of $   to a high of $   for each share of Treeline Common Stock.

The value of the Merger consideration will also be impacted by the amount of Parent Net Cash (as defined in the Merger Agreement) that Standard BioTools has at Closing. The Exchange Ratio, which determines the number of shares of Standard BioTools Common Stock to be issued to former Treeline stockholders, will vary in part based on the amount of Parent Net Cash that Standard BioTools has at Closing. To the extent that Parent Net Cash is more than $451 million, the Exchange Ratio will be lower and Treeline stockholders will receive fewer shares of Standard

BioTools Common Stock; to the extent that Parent Net Cash is less than $449 million, the Exchange Ratio will be higher and Treeline stockholders will receive more shares of Standard BioTools Common Stock, resulting in incremental dilution to the Standard BioTools stockholders. The term “Parent Net Cash,” as defined in the Merger Agreement, will be reduced by the amount of certain liabilities of Standard BioTools at Closing.

The Merger Agreement contains “no shop” provisions that restrict each of Standard BioTools’ and Treeline’s ability to solicit, initiate, induce, knowingly encourage or knowingly facilitate, or take any other action designed to facilitate, competing third-party proposals relating to a merger, reorganization or consolidation of the respective company or an acquisition of the respective company’s stock or assets. In addition, Standard BioTools generally has an opportunity to offer to modify the terms of the Merger Agreement in response to any competing acquisition proposals before the Standard BioTools Board may withdraw or qualify its recommendation with respect to the Merger. If the Merger Agreement is terminated in connection with the pursuit of a third-party transaction by Standard BioTools, Standard BioTools will be required to pay a termination fee of $16.1 million to Treeline and/or reimburse up to a maximum of $5.0 million of Treeline’s expenses. See “The Merger Agreement — Termination” and “The Merger Agreement — Termination Fee and Expense Reimbursement” beginning on pages 243 and 244, respectively, of this proxy statement/prospectus.

These provisions could discourage a potential third-party acquirer that might have an interest in acquiring all or a significant portion of Standard BioTools from considering or proposing an acquisition, even if it were prepared to pay consideration with a higher per share cash or market value than the market value proposed in the Merger. A potential third-party acquirer maintaining interest in the face of these provisions might propose to pay a lower price to Standard BioTools stockholders than it might otherwise have proposed to pay because of the added expense of the termination fee and expense reimbursement described above.

If the Merger Agreement is terminated and Standard BioTools determines to seek another business combination, it may not be able to negotiate a transaction with another party on terms comparable to, or better than, the terms of the Merger.

The Merger Agreement provides that all of the representations and warranties of the parties contained therein shall not survive the Closing. As a result, following the consummation of the Merger, neither the combined company nor any of its stockholders will have any remedy available under the Merger Agreement if it is later revealed that there was a breach of any of the representations or warranties made by Standard BioTools, Treeline or Merger Sub at or prior to the time of the Merger. This means that the combined company will bear the risk of any undisclosed or unknown liabilities of Standard BioTools, Treeline or Merger Sub that existed at or prior to the Closing, and the combined company’s stockholders will have no contractual recourse against the former stockholders of Standard BioTools, Treeline or Merger Sub for any such liabilities. This is a material departure from the protections typically available in private company acquisition transactions, where the representations and warranties of the target company often survive the closing for a specified period and the acquiror has indemnification rights for breaches thereof. The absence of post-closing indemnification protections could have a material adverse effect on the combined company’s financial condition and results of operations if undisclosed liabilities materialize after the Closing.

The announcement and pendency of the Merger could disrupt Standard BioTools’ and Treeline’s businesses, in any of the following ways, among others:

These disruptions could be exacerbated by a delay in the completion of the Merger or termination of the Merger Agreement. Additionally, if the Merger is not consummated, each company will have incurred significant costs and diverted the time and attention of management. A failure to consummate the Merger may also result in negative publicity, reputational harm, litigation against Standard BioTools, Treeline and/or their respective directors and officers, and a negative impression of the companies in the financial markets. The occurrence of any of these events individually or in combination could have a material adverse effect on either or both companies’ financial performance and stock price.

The Merger Agreement restricts Standard BioTools and Treeline from taking certain actions until the Effective Time without the consent of the other party, including, among others: the payment of dividends; the issuance of equity (including certain equity incentive awards); certain increases to employee compensation and benefits; capital expenditures; the incurrence of indebtedness; acquisitions and divestitures (other than with respect to the Legacy Businesses, including the Mass Cytometry Divestiture); and the entry into or amending certain material contracts. Standard BioTools and Treeline are required to conduct their business in the ordinary course of business in all material respects.

The restrictive covenants, which are subject to various specific exceptions, may prevent Standard BioTools or Treeline from pursuing attractive business opportunities that may arise prior to the consummation of the Merger. Although Standard BioTools and Treeline may be able to pursue such activities with the other company’s consent, the other company may not be willing to provide its consent. For a description of the restrictive covenants applicable to Standard BioTools and Treeline, see “The Merger Agreement — Covenants; Conduct of Business Pending the Merger” beginning on page 236 of this proxy statement/prospectus.

In general, neither Standard BioTools nor Treeline is obligated to complete the Merger if there is a continuing material adverse effect affecting the other party between June 6, 2026, the date of the Merger Agreement, and the Closing. However, certain types of changes are excluded from the concept of a “material adverse effect.”

Such exclusions include, but are not limited to, general business or economic conditions generally affecting the industry in which the applicable party operates; political conditions, acts of war, the outbreak or escalation of armed hostilities, acts of terrorism, earthquakes, wildfires, hurricanes, tsunamis, floods, mudslides, weather conditions, other natural disasters, man-made disasters, health and other emergencies, calamities, epidemics, pandemics (including COVID-19 and any evolutions or mutations thereof), disease outbreaks, other acts of God or force majeure events; changes in financial, banking or securities markets, including changes in interest rates in the United States or any other country or region in the world; any change in law or GAAP; any change in the stock price or trading volume of Standard BioTools Common Stock; a failure to meet internal or analysts’ expectations or projections; and the execution or announcement of the Merger Agreement or the pendency of the Merger.

Therefore, if any of these events were to occur, impacting Standard BioTools or Treeline, the other party would still be obliged to consummate the Closing. If any such adverse changes occur and Standard BioTools and Treeline consummate the Closing, the stock price of the combined company may suffer. This in turn may reduce the value of the Merger to the stockholders of Standard BioTools, Treeline or both. For a more complete discussion of what

constitutes a material adverse effect on Standard BioTools or Treeline, see the section entitled “The Merger Agreement — Conditions to the Completion of the Merger” beginning on page 226 of this proxy statement/prospectus.

Additional financing may not be available to the combined company when it is needed or may not be available on favorable terms. To the extent that the combined company raises additional capital by issuing equity securities, or debt securities convertible into equity securities, such financing will cause additional dilution to all of the securityholders of the combined company, including Standard BioTools’ pre-Merger stockholders and Treeline’s former stockholders, and could have an adverse impact on the combined company’s stock price. It is also possible that the terms of any new equity securities may have preferences over the combined company’s common stock. Any debt financing the combined company enters into may include covenants that restrict its operations. These restrictive covenants may include limitations on additional borrowing and specific restrictions on the use of the combined company’s assets, as well as prohibitions on its ability to create liens, pay dividends, redeem its stock or make investments. In addition, if the combined company raises additional funds through licensing arrangements, it may be necessary to grant licenses on terms that are not favorable to the combined company. Any such financings could have a material adverse effect on the combined company.

In July and August 2026, Standard BioTools received demand letters from purported shareholders, each of which alleged that this proxy statement/prospectus omits certain material information and seeks additional disclosures and one of which seeks inspection of Standard BioTools’ books and records pursuant to Section 220 of the DGCL. These demand letters could lead to lawsuits, and additional demand letters may be received or lawsuits filed. The outcome of any lawsuit that may be filed challenging the Merger is uncertain. One of the conditions to the Closing is that no applicable law, judgment (whether temporary, preliminary or permanent) or other legal restraint or binding order or determination by any governmental entity of competent jurisdiction shall be in effect that prevents, restrains, enjoins, makes illegal or otherwise prohibits the consummation of the Merger or any of the other transactions contemplated by the Merger Agreement.

Accordingly, if any future lawsuit is successful in obtaining an order enjoining consummation of the Merger, then such order may prevent the Merger from being consummated, or from being consummated within the expected time frame, and could result in substantial costs to Standard BioTools and Treeline, including but not limited to, legal fees and costs associated with the indemnification of directors and officers. Any such injunction or delay in the Merger being completed may adversely affect Standard BioTools’ or Treeline’s business, financial condition, results of operations, and cash flows.

Certain of the directors and executive officers of Standard BioTools and Treeline have interests in the Merger that may be different from, or in addition to, those of Standard BioTools and Treeline stockholders. These interests include, but are not limited to, the continued service of certain Standard BioTools and Treeline directors as directors and of Treeline executive officers as executive officers of the combined company after the date of consummation of the Merger (the “Closing Date”), in respect of the Treeline executive officers, assumption of their Treeline Options by Standard BioTools in accordance with the Merger Agreement, and in respect of the Standard BioTools directors and executive officers, accelerated vesting of Standard BioTools equity awards held by Standard BioTools non-employee directors on the Closing Date, receipt of a pro rata portion of the Merger consideration by affiliates of Casdin Capital, LLC (which owns 5.28% of Treeline and of which Eli Casdin, a director of Standard BioTools, is the Founder and Chief Investment Officer), certain severance payments and benefits (including acceleration of equity awards) for Standard BioTools executive officers in the event of a qualifying termination in connection with the consummation of the transactions contemplated by the Merger Agreement pursuant to the Standard BioTools CIC Severance Plans, extension of the post-employment exercise period for 30 months for certain Standard BioTools

Options held by Standard BioTools executive officers, a possible transitional consulting agreement between Treeline and Sean Mackay, and provisions in the Merger Agreement regarding continued indemnification of and advancement of expenses of the directors and executive officers of Standard BioTools and Treeline. Standard BioTools stockholders should be aware of these interests when they consider the recommendation of the Standard BioTools Board that they vote in favor of the Merger-related proposals.

The members of the Standard BioTools Board and the Treeline Board were aware of and considered these interests relating to Standard BioTools and Treeline, among other matters, in evaluating the Merger Agreement and the Merger, and in recommending that Standard BioTools stockholders approve the Proposals. The interests of Standard BioTools and Treeline directors and executive officers are described in more detail under “The Merger — Interests of Standard BioTools Directors and Executive Officers in the Merger” beginning on page 202 and “The Merger — Interests of Treeline’s Directors and Executive Officers in the Merger” beginning on page 207 of this proxy statement/prospectus.

Standard BioTools currently develops, manufactures and sells a diversified range of instrumentation, consumables, and services that help scientists and biomedical researchers develop better therapeutics faster. Its proprietary multi-omics tools are used in a broad range of applications, including proteomics and genomics, and other areas of translational and clinical research. Its instruments and consumables are sold to leading academic research institutions, translational research and medicine centers, cancer centers, clinical research laboratories, and biopharmaceutical, biotechnology, and plant and animal research companies.

In connection with the Merger, Standard BioTools expects to sell or otherwise monetize its Legacy Businesses, and the business of the combined company will consist of Treeline’s business. Treeline is a clinical-stage biopharmaceutical company that matches compelling biological targets with proven drug approaches, including small molecule inhibitors, protein degraders, and targeted therapy antibody-drug conjugates, by integrating in-house R&D with leading-edge computational tools. Treeline’s pipeline spans oncology, neurology and immunology.

This change in the business of Standard BioTools from manufacturing and selling instruments to being a clinical-stage biopharmaceutical company could have a significant impact on the trading and market price of the common stock of the combined company following the Merger. The change in business may attract different investors and analysts and could result in the combined company’s common stock being more volatile than it was prior to the Merger. We cannot predict with certainty how the change in business will impact the combined company’s common stock following the consummation of the Merger. There can be no assurance that the change in business will not have a material adverse impact on the trading price and liquidity of the combined company’s common stock.

Following the consummation of the Merger, the board of directors of the combined company is expected to consist of 12 members, including 10 director designees of Treeline and two director designees of Standard BioTools. In addition, the management team of Treeline will become the management team of Standard BioTools. In particular, Joshua Bilenker, currently the chief executive officer and co-founder of Treeline, will serve as Chief Executive Officer of the combined company, Jeffrey Engelman, currently the chief scientific officer and co-founder of Treeline, will serve as Chief Scientific Officer of the combined company, and Spencer Smith, currently the chief financial officer of Treeline, will serve as Chief Financial Officer of the combined company.

This change in board membership and management of the combined company may affect the combined company’s business strategy and operating decisions following the consummation of the Merger, as compared to those of Standard BioTools prior to the Merger. In addition, there can be no assurances that the board of directors of the combined company will function effectively as a team and that any differences or difficulties, should they arise, will not have an adverse effect on the combined company’s business or results after the Closing Date.

Immediately following completion of the Merger and the issuance of the Standard BioTools Common Stock to the Treeline stockholders at the Effective Time, Standard BioTools’ current stockholders in the aggregate will not have a majority ownership and voting interest in the combined company, which will result in Standard BioTools stockholders having less influence on the combined company’s management and policies. Immediately following completion of the Merger and using an estimated Exchange Ratio based on Standard BioTools’ and Treeline’s capitalization as of June 3, 2026 and May 28, 2026, respectively, and taking into account Standard BioTools’ estimated cash position as of the Closing but excluding any effect of the Reverse Stock Split, Treeline stockholders and Standard BioTools stockholders are expected to own approximately 84% and 16%, respectively, of the combined company’s outstanding shares on a fully diluted basis. As a result, current Standard BioTools stockholders will have significantly less influence on the combined company’s management and policies than they currently have.

The outstanding shares of Treeline Capital Stock are privately held and are not traded in any public market. The lack of a public market makes it extremely difficult to determine the fair market value of the shares of Treeline Capital Stock. Because the Exchange Ratio that will be used to calculate the number of shares of Standard BioTools Common Stock to be issued to Treeline stockholders was determined based on negotiations between the parties, it is possible that Standard BioTools may pay more than the aggregate fair market value for the shares of Treeline Capital Stock.

The opinion rendered to the Standard BioTools Board by Centerview and the opinion rendered to the Standard BioTools Special Committee by UBS were provided in connection with, and at the time of, the Standard BioTools Board’s and Standard BioTools Special Committee’s respective evaluations of the Merger. These opinions were based on the respective financial analyses performed, which considered market and other conditions then in effect, and financial forecasts and other information made available to Centerview and UBS, as of the date of their respective opinions, which may have changed, or may change, after the date of the opinions.

Neither the Standard BioTools Board nor the Standard BioTools Special Committee has obtained updated opinions from their respective financial advisors as of the date of this proxy statement/prospectus or as of any other date, nor does either expect to receive updated, revised or reaffirmed opinions prior to the consummation of the Merger. Changes in the operations and prospects of Treeline or Standard BioTools, general market and economic conditions and other factors that may be beyond the control of Treeline or Standard BioTools, and which changes were not taken into account by Standard BioTools’ financial advisors in rendering their respective opinions, may significantly alter the value of Treeline or Standard BioTools or the prices of Treeline Common Stock or Standard BioTools Common Stock by the time the Merger is consummated. The opinions do not speak as of the time the Merger will be consummated or as of any date other than the date of such opinions.

Because there are no plans for Standard BioTools’ financial advisors to update their opinions, the opinions do not address the fairness of the Exchange Ratio or the Merger consideration, as applicable, from a financial point of view, at any time other than the time such opinions were rendered, even though the Standard BioTools Board’s recommendation that Standard BioTools stockholders vote “FOR” the Standard BioTools Proposals is made as of the date of this proxy statement/prospectus. For a description of the opinions that the Standard BioTools Board and the Standard BioTools Special Committee received from their respective financial advisors, see “The Merger — Opinion of Standard BioTools’ Financial Advisor” beginning on page 188 of this proxy statement/prospectus and “The Merger — Opinion of Standard BioTools Special Committee’s Financial Advisor” beginning on page 194 of this proxy statement/prospectus.

If the Merger is not consummated for any reason, Standard BioTools may be subject to a number of material risks, including the following:

In addition to the above risks, Standard BioTools may be required, under certain circumstances, to pay a termination fee of $16.1 million to Treeline, including if Treeline terminates the Merger Agreement due to a change in the Standard BioTools Board recommendation in favor of the Merger Transactions, or in some cases reimburse Treeline’s reasonable out-of-pocket transaction-related expenses (up to a maximum of $5.0 million), including if Treeline terminates the Merger Agreement due to a failure to obtain the required approval of Standard BioTools stockholders, which may adversely affect Standard BioTools’ financial condition.

The business of Standard BioTools may be adversely impacted by the failure to pursue other beneficial opportunities due to the focus of Standard BioTools management on the Merger. A failure to consummate the Merger may also result in negative publicity, reputational harm, potential litigation against Standard BioTools or its directors and officers, and a negative impression of the companies in the financial markets. If the Merger is not consummated, we cannot assure the Standard BioTools stockholders that these risks will not materialize and will not materially adversely affect the business, financial results and stock price of Standard BioTools.

If the Merger is not completed, and there is no superior alternative transaction available, the Standard BioTools Board may decide to pursue a dissolution and liquidation of the Standard BioTools business if it concludes that such strategy is in the best interests of the Standard BioTools stockholders. In such an event, the amount of cash available for distribution to Standard BioTools’ stockholders will depend heavily on the timing of such decision and, with the passage of time, the amount of cash available for distribution will be reduced as Standard BioTools continues to fund its operations.

In addition, if the Standard BioTools Board were to approve and recommend, and Standard BioTools stockholders were to approve, a dissolution and liquidation, Standard BioTools would be required under Delaware corporate law to pay its outstanding obligations, as well as to make reasonable provision for contingent and unknown obligations, prior to making any distributions in liquidation to Standard BioTools’ stockholders. As a result of this requirement, a portion of Standard BioTools’ assets may need to be reserved pending the resolution of such obligations and the timing of any such resolution is uncertain. In addition, Standard BioTools may be subject to litigation or other claims related to a dissolution and liquidation.

If a dissolution and liquidation were pursued, the Standard BioTools Board, in consultation with its advisors, would need to evaluate these matters and make a determination about a reasonable amount to reserve. Accordingly, holders of Standard BioTools Common Stock could lose all or a significant portion of their investment in the event of a liquidation, dissolution or winding up.

Appraisal rights are statutory rights that, if applicable under law, enable stockholders to dissent from an extraordinary transaction, such as a merger, and to demand that the corporation pay the fair value for their shares as determined by a court in a judicial proceeding instead of receiving the consideration offered to stockholders in connection with the extraordinary transaction.

Under § 262(b) of the DGCL, stockholders do not have appraisal rights if the shares of stock they hold, as of the record date for determination of stockholders entitled to vote at the meeting of stockholders to act upon a merger, are either (i) listed on a national securities exchange or (ii) held of record by more than 2,000 holders. Notwithstanding the foregoing, appraisal rights are available if stockholders are required by the terms of the Merger Agreement to accept for their shares anything other than (a) shares of stock of the surviving corporation, (b) shares of stock of another corporation that will either be listed on a national securities exchange or held of record by more than 2,000 holders, (c) cash instead of fractional shares or (d) any combination of clauses (a) through (c).

Because the Standard BioTools Common Stock is listed on The Nasdaq Global Select Market, a national securities exchange, and is expected to continue to be so listed on the Record Date, Standard BioTools stockholders will not be entitled to appraisal rights in the Merger with respect to their Standard BioTools Common Stock.

The unaudited forecasted financial information included in this proxy statement/prospectus is presented for illustrative purposes only and is not necessarily indicative of what the combined company’s actual financial condition or results of operations would have been had the Merger been completed on the dates indicated, nor is it indicative of the future financial condition or results of operations of the combined company.

The forecasted financial information included in this proxy statement/prospectus was not prepared with a view toward public disclosure, and such unaudited forecasted financial information was not prepared with a view toward compliance with published guidelines of any regulatory or professional body for the preparation or presentation of prospective financial information, including the published guidelines of the SEC and the guidelines established by the American Institute of Certified Public Accountants. Neither the independent accountants of Standard BioTools or Treeline, nor any other independent accountants, have audited, reviewed, compiled or applied agreed upon procedures, examined or performed any procedures with respect to the forecasted financial information contained herein, nor have they expressed any opinion or any other form of assurance on such information or the achievability thereof, and, accordingly, such independent accountants assume no responsibility for, and disclaim any association with, Standard BioTools’ and Treeline’s forecasted financial information. The reports of the auditors of Standard BioTools and Treeline included or incorporated by reference in this proxy statement/prospectus relate to previously issued financial statements and do not extend to the forecasted financial information, and should not be read to do so, and, accordingly, such independent accountants assume no responsibility for, and disclaim any association with, the forecasted financial information. Further, no other independent accountants have compiled, examined or performed any procedures with respect to the forecasted financial information contained herein, nor have they expressed any opinion or any other form of assurance on such information or the achievability thereof.

The forecasted financial information included in this proxy statement/prospectus speaks only as of the date on which such information was prepared, and neither Standard BioTools nor Treeline undertakes any obligation, other than as required by applicable law, to update the forecasted financial information included herein to reflect events or circumstances after the date the forecasted financial information was prepared or to reflect the occurrence of anticipated or unanticipated events or circumstances.

The market price of the Standard BioTools Common Stock could fall following the consummation of the Merger. At the Closing, we expect that Standard BioTools will issue approximately two billion shares of Standard BioTools Common Stock (excluding the effect of the Reverse Stock Split) as merger consideration to the Treeline stockholders. Treeline stockholders may decide not to hold the Standard BioTools Common Stock they receive in the Merger. Other Treeline stockholders, such as funds with limitations on the amount of stock they are permitted to hold in individual issuers, may be required to sell Standard BioTools Common Stock that they receive in the Merger.

Such sales, or market perception of such sales, of Standard BioTools Common Stock could result in a higher-than-average trading volume following the Closing and may cause the market price for Standard BioTools Common Stock to decline.

Standard BioTools or Treeline may agree to waive (to the extent permitted by applicable law), in whole or in part, some of the conditions to each party’s obligations to complete the Merger, to the extent permitted by applicable law. For example, it is a condition to Standard BioTools’ and Treeline’s respective obligations to close the Merger that certain of the representations and warranties of the other party are true and correct in all respects as of the Closing Date, except where the failure of such representations and warranties to be true and correct would not have a material adverse effect. However, if the board of directors of either party determines that it is in the best interests of the stockholders of that company to waive any breach of representation by the other party, then such board of directors may elect to waive that condition (to the extent permitted by applicable law).

In the event of a waiver of a condition (to the extent permitted by applicable law), the Standard BioTools Board will evaluate the materiality of any such waiver to determine whether amendment of this proxy statement/prospectus and re-solicitation of proxies is necessary. In the event that the Standard BioTools Board, in its own reasonable discretion, determines any such waiver is not significant enough to require re-solicitation of its stockholders, it will have the discretion to cause the Merger to be completed without seeking further stockholder approval, which decision may have a material adverse effect on the stockholders of the combined company following the Merger. For example, the market could react negatively to such information, which may cause a substantial decline in the price of the common stock of the combined company following the Merger.

Notwithstanding the foregoing, certain closing conditions may not be waived due to applicable law or otherwise. The following closing conditions may not be waived: receipt of the requisite stockholder approvals; the effectiveness of the registration statement on Form S-4 of which this proxy statement/prospectus forms a part; and the absence of any order or injunction that has the effect of prohibiting the consummation of the Merger. The foregoing closing conditions are the only closing conditions to the Merger that may not be waived. All other closing conditions to the Merger may be waived (to the extent permitted by applicable law) by Standard BioTools and/or Treeline, as applicable. See the section “The Merger Agreement — Conditions to the Completion of the Merger” for further information.

Standard BioTools has incurred significant net losses since its inception and cannot guarantee when, if ever, it will become profitable. Unused net operating loss (“NOL”) and tax credit carryforwards will generally carry forward to offset future taxable income, subject to applicable limitations on the use of those losses. Federal NOLs incurred in taxable years ending on or before December 31, 2017 are eligible to be carried forward for up to 20 years, and to be deducted in full against income for the years to which they may be carried. Federal NOLs incurred in taxable years ending after December 31, 2017 are eligible to be carried forward indefinitely, but may offset no more than 80% of the taxable income for the years to which they are carried (computed without regard to the deduction for carryovers of NOLs). To the extent they expire unused, these NOLs and tax credit carryforwards will not be available to offset future income tax liabilities.

In addition, under Sections 382 and 383 of the Code, and corresponding provisions of state law, if a corporation undergoes an “ownership change,” which is generally defined as a greater than 50% change, by value, in its equity ownership over a three-year period, the corporation’s ability to use its pre-change NOLs and tax credit carryovers to reduce its tax liability for post-change periods may be limited. Standard BioTools has experienced ownership changes in the past, will experience an ownership change as a result of the Merger, and may experience future ownership changes as a result of subsequent shifts in its stock ownership, some of which may be outside of its control. As a result, Standard BioTools’ ability to use its historical NOLs and tax credit carryovers to offset future income tax liabilities is limited by prior ownership changes and may become limited by additional ownership changes in the future (including any ownership change resulting from the Merger).

The right of Standard BioTools stockholders to receive any future payment for or derive any value from the CVRs will be contingent in part upon the combined company’s receipt of (i) proceeds from any sale, disposition, or other monetization of the Legacy Businesses, including any cash proceeds received in connection with the Mass Cytometry Divestiture during the five-year term of the CVRs; (ii) proceeds from convertible notes or other investments held by Standard BioTools as of the Closing Date; (iii) earnout, milestone, royalty or other similar contingent payments due to Standard BioTools under contracts in effect as of the Closing Date; and (iv) any surplus in Parent Net Cash delivered at Closing as finally determined under the Merger Agreement, and the timing and amount of the consideration received thereunder. For example, the aggregate purchase price for the Mass Cytometry Divestiture of $5 million (subject to customary adjustments as contemplated by the Mass Cytometry Purchase Agreement) is payable entirely through the issuance to Standard BioTools by Multiplex Bio, at the consummation of the Mass Cytometry Divestiture, of a promissory note in a principal amount equal to $5 million, bearing interest at a rate of 6% per annum and maturing on the fifth anniversary of the consummation of the Mass Cytometry Divestiture. Because the only proceeds that the CVR captures with respect to the Mass Cytometry Divestiture will be cash proceeds, Standard BioTools stockholders will only receive any future payment for or derive any value from the CVR in connection with the Mass Cytometry Divestiture to the extent such promissory note is satisfied, and the combined company receives cash proceeds therefrom, during the five-year term of the CVR Agreement. If the promissory note is not satisfied or the combined company does not receive cash proceeds therefrom during the time period specified in the CVR Agreement, no payment will be made in respect of the CVRs in connection with the Mass Cytometry Divestiture. Additionally, if the combined company is not successful in entering into disposition agreements related to the remaining portion of the Legacy Businesses not sold to Multiplex Bio in the Mass Cytometry Divestiture or receiving payments thereunder within the time period specified in the CVR Agreement, there are no proceeds from convertible notes or other investments, there are no earnout, milestone, royalty or other similar payments under existing Standard BioTools contracts, and there is no Parent Net Cash surplus, no payments will be made in respect of the CVRs.

Following the Effective Time, the combined company will have sole authority over whether and how to monetize the remaining portion of the Legacy Businesses (if at all), and the combined company’s only obligations will be to carry out the obligations set forth in the CVR Agreement. Furthermore, the CVRs will be unsecured obligations of the combined company and all payments under the CVRs and all other obligations under the CVR Agreement and the CVRs and any rights or claims relating thereto will be subordinated in right of payment to the prior payment in full of all current or future senior obligations of the combined company. Accordingly, there can be no assurance that holders of CVRs will receive any payments with respect to the CVRs.

Any payments under the CVRs will be made in shares of the combined company’s common stock, subject to the maximum cap of 76,000,000 shares. If substantial payments are made under the CVRs, the issuance of such shares will dilute the ownership percentage of all stockholders of the combined company who are not CVR holders, including former Treeline stockholders. This dilution could be material if the Legacy Businesses are sold or monetized at a significant value during the CVR payment period. Additionally, any such shares paid in respect of the CVRs will be subject to market conditions and may decline in value following payment.

In addition, CVR holders will have limited ability to transfer their CVRs, which are not registered with the SEC and will not trade on any securities exchange. The CVRs are illiquid instruments with no established market, and CVR holders may be unable to sell, assign or otherwise dispose of their CVRs except in the limited circumstances specified in the CVR Agreement. The illiquidity of the CVRs may make it difficult for CVR holders to realize any value from their CVRs prior to the expiration of the CVR Agreement.

Standard BioTools intends to treat a holder’s receipt of the CVRs as a non-taxable distribution with respect to the holder’s existing shares of Standard BioTools Common Stock for U.S. federal income tax purposes. However, the U.S. federal income tax treatment of the CVRs is uncertain. There is no legal authority directly addressing the U.S. federal income tax treatment of the receipt of, and payments under, the CVRs, and there can be no assurance that the Internal Revenue Service (“IRS”) would not assert, or that a court would not sustain, a position that could result in adverse U.S. federal income tax consequences to holders of the CVRs. For example, the IRS may assert that the distribution of the CVRs is a taxable distribution of property, which would be taxable as a dividend to the extent of the holder’s pro rata share of Standard BioTools’ current and accumulated earnings and profits, if any, with any

excess being treated as a return of capital to the extent thereof and then as capital gain. For more information regarding the U.S. federal income tax considerations with respect to the CVRs, see the section titled “The Merger — CVR Agreement” and “The Merger — Material U.S. Federal Income Tax Considerations with Respect to the CVRs to Holders of Standard BioTools Common Stock.”

A principal purpose of the Reverse Stock Split is to increase the per-share market price of Standard BioTools’ Common Stock above the minimum bid price requirement under the Nasdaq listing rules in order to facilitate the listing of the shares of Standard BioTools Common Stock being issued in the Merger on Nasdaq. It cannot be assured, however, that the Reverse Stock Split will accomplish this objective for any meaningful period of time. While it is expected that the reduction in the number of outstanding shares of Standard BioTools Common Stock will proportionally increase the market price of the Standard BioTools Common Stock, it cannot be assured that the Reverse Stock Split will increase the market price of the Standard BioTools Common Stock by a multiple of the Reverse Stock Split ratio mutually agreed by Standard BioTools and Treeline, or result in any permanent or sustained increase in the market price of the Standard BioTools Common Stock, which is dependent upon many factors, including Standard BioTools’ business and financial performance, general market conditions and prospects for future success.

Thus, there is no assurance that the Reverse Stock Split will sufficiently increase the per-share market price of the Standard BioTools Common Stock in order to facilitate the listing of the shares of Standard BioTools Common Stock being issued in the Merger on Nasdaq. In addition, even if the stock price of the Standard BioTools Common Stock meets the listing requirements for Nasdaq initially, it cannot be assured that the stock price will continue to do so.

Although the Standard BioTools Board believes that the anticipated increase in the market price of the combined company’s common stock resulting from the Reverse Stock Split could encourage interest in the combined company’s common stock and possibly promote greater liquidity for its stockholders, such liquidity could also be adversely affected by the reduced number of shares outstanding after the Reverse Stock Split. The reduction in the number of outstanding shares may lead to reduced trading and a smaller number of market makers for the combined company’s common stock.

Should the market price of the combined company’s common stock decline after the Reverse Stock Split, the percentage decline may be greater, due to the smaller number of shares outstanding, than it would have been prior to the Reverse Stock Split. A reverse stock split is often viewed negatively by the market and, consequently, can lead to a decrease in the combined company’s overall market capitalization. If the per share market price does not increase in proportion to the Reverse Stock Split ratio, then the value of the combined company, as measured by its stock capitalization, will be reduced. In some cases, the per-share stock price of companies that have effected reverse stock splits subsequently declined back to pre-reverse split levels, and accordingly, it cannot be assured that the total market value of the combined company’s common stock will remain the same after the reverse stock split is effected, or that the reverse stock split will not have an adverse effect on the combined company’s stock price due to the reduced number of shares outstanding after the reverse stock split.

The negotiation and consummation of the Merger may require more time or greater cash resources than anticipated and expose the combined company to other operational and financial risks, including:

Many of these factors are outside the control of Standard BioTools and Treeline, and any one of them could result in increased costs, decreased expected revenues and diversion of management time and energy, which could materially impact the business, financial condition, results of operations and cash flows of the combined company. These factors could cause dilution to the earnings per share of the combined company, decrease or delay the expected benefits expected from the Merger and negatively impact the price of Standard BioTools Common Stock. As a result, it cannot be assured that the combined company will realize the full benefits anticipated from the Merger within the anticipated time frames, or at all.

In addition, following the Merger, it is possible that there may be unknown, contingent or other liabilities or problems that may arise in the future, the existence and/or magnitude of which Standard BioTools was previously unaware. Any such liabilities or problems could have an adverse effect on the combined company’s business, financial condition, results of operations or cash flows.

Even if the Merger is successfully consummated, there can be no assurance that the Merger will result in the realization of the full benefit for the combined company’s stockholders or that these benefits will be realized within the expected time frames or at all. Difficulties in achieving these benefits could harm the reputation of the combined company. In addition, by engaging in the Merger, Standard BioTools may forego or delay pursuit of other opportunities that may have proven to have greater commercial potential.

Standard BioTools and Treeline will incur substantial expenses in connection with and as a result of consummating the Merger, and over a period of time following the consummation of the Merger, the combined company will incur substantial expenses in connection with coordinating and operating the businesses of Treeline and, to the extent not sold or otherwise monetized prior to consummation of the Merger, Standard BioTools. A portion of the transaction costs related to the Merger will be incurred regardless of whether the Merger is consummated. While Standard BioTools and Treeline have assumed that a certain level of transaction expenses will be incurred, factors beyond Standard BioTools’ and Treeline’s control could affect the total amount or the timing of these expenses. Although many of the expenses that will be incurred, by their nature, are difficult to estimate accurately, the current estimate of the aggregate expenses that will be incurred by Standard BioTools and Treeline is approximately     , which is subject to change. These expenses may exceed the costs historically borne by Standard BioTools and Treeline. These expenses could adversely affect the financial condition, results of operations and cash flows of the combined company following the consummation of the Merger.

The unaudited pro forma financial information included in this proxy statement/prospectus is presented for informational purposes only and may not be an indication of what Standard BioTools’ financial position or results of operations would have been had the Merger been consummated on the dates indicated. The unaudited pro forma financial information has been derived from the audited and unaudited historical financial statements of Standard BioTools and Treeline and certain adjustments and assumptions regarding Standard BioTools after giving effect to the Merger.

The information upon which these adjustments and assumptions have been made is preliminary, and such adjustments and assumptions are difficult to make with accuracy. Moreover, the unaudited pro forma financial information do not reflect all costs that are expected to be incurred by the combined company in connection with the Merger. For example, the impact of any incremental costs incurred in integrating the two companies is not reflected in the unaudited pro forma financial information. As a result, the actual financial condition of the combined company following the Merger may not be consistent with, or evident from, these unaudited pro forma condensed combined financial statements.

In addition, the assumptions used in preparing the unaudited pro forma financial information may not prove to be accurate, and other factors may affect the combined company’s financial condition or results of operations following the consummation of the Merger. Any material variance from the pro forma financial information may cause significant variations in the market price of the Standard BioTools Common Stock. See “Unaudited Pro Forma Condensed Combined Financial Information” beginning on page 352 of this proxy statement/prospectus.

On June 30, 2026, there were 392,120,900 outstanding shares of Standard BioTools Common Stock, and Standard BioTools’ basic and diluted net loss per share from continuing operations for the six months ended June 30, 2026 was $0.09. It is anticipated that up to 2,025,718,733 shares of Standard BioTools Common Stock will be issued in connection with the Merger, and the basic and diluted net loss per share from continuing operations for the combined company, on a pro forma basis, will be $0.06 for the six months ended June 30, 2026. As such, the Merger will be dilutive to Standard BioTools’ earnings per share.

Standard BioTools’ net tangible book value as of June 30, 2026 was approximately $539,971,000, or $1.38 per share, based on 392,120,900 outstanding shares of Standard BioTools Common Stock on such date. After giving effect to the Merger, Standard BioTools’ as adjusted net tangible book value as of June 30, 2026 would have been approximately $1,042,136,000, or $0.43 per share. This represents an immediate decrease in net tangible book value of $0.95 per share to existing Standard BioTools stockholders and immediate dilution of $0.39 per share to Treeline stockholders receiving shares of Standard BioTools Common Stock in connection with the Merger, as compared to the $0.82 closing price of Standard BioTools shares on Nasdaq on June 30, 2026.

Immediately following the Merger, Standard BioTools stockholders as of immediately prior to the Merger are expected to own approximately 16% of the outstanding capital stock of the combined company on a fully diluted basis, and former Treeline stockholders are expected to own approximately 84% of the outstanding capital stock of the combined company on a fully diluted basis. As a result, the issuance of Standard BioTools Common Stock in connection with the Merger will significantly reduce the relative voting power of existing Standard BioTools stockholders and dilute their percentage interest in any future earnings, dividends or other distributions of Standard BioTools. The actual extent of any such dilution will depend on a number of factors, including the number of shares of Standard BioTools Common Stock outstanding at the effective time of the merger, the future operating results of Standard BioTools and the combined company, and the timing and amount of any future issuances of Standard BioTools Common Stock, common stock of the combined company or other equity securities by Standard BioTools or the combined company.

The following table quantifies, on a disaggregated basis, the potential dilutive effect of the Merger and other agreements of Standard BioTools.

Future events and conditions could increase the dilution that is currently projected, including adverse changes in market conditions, additional transaction and integration-related costs and other factors such as the failure to realize some or all of the benefits anticipated in the Merger. Any dilution of, or delay of any accretion to, Standard BioTools’ earnings per share could cause the price of Standard BioTools’ Shares to decline or grow at a reduced rate.

The combined company may require additional capital to finance its operations, which may not be available on acceptable terms or at all. The combined company’s future capital requirements will depend upon a number of factors, including: the number and timing of future product candidates in the pipeline; progress with and results from preclinical testing and clinical trials; the ability to manufacture sufficient drug supplies to complete preclinical and clinical trials; the costs involved in preparing, filing, acquiring, prosecuting, maintaining and enforcing patent and other intellectual property claims; and the time and costs involved in obtaining regulatory approvals and favorable reimbursement or formulary acceptance. If the combined company is required to seek additional funding in the future, it may seek to do so through public or private equity offerings or debt financings, credit or loan facilities or a combination of one or more of these funding sources.

If the combined company raises additional funds by issuing equity securities, its stockholders will suffer dilution and the terms of any financing may adversely affect the rights of its stockholders. In addition, as a condition to providing additional funds, future investors may demand, and may be granted, rights superior to those of existing stockholders. Debt financing, if available, would subject the combined company to fixed payment obligations and is likely to involve restrictive covenants limiting the combined company’s flexibility in conducting future business activities, and, in the event of insolvency, debt holders would be repaid before holders of the combined company’s equity securities would receive any distribution of corporate assets. Additionally, global economic instability, higher interest rates and diminished credit availability may limit the combined company’s ability to obtain debt financing

on favorable terms. If the combined company raises additional capital through marketing and distribution arrangements or other collaborations, strategic alliances or licensing arrangements with third parties, the combined company may have to relinquish certain valuable intellectual property or other rights to its product candidates, technologies, future revenue streams or research programs or grant licenses on terms that may not be favorable to it.

The ability to raise additional funds will depend on financial, economic and other factors, many of which are beyond the combined company’s control. Fundraising efforts may divert management from their day-to-day activities, which may adversely affect the combined company’s ability to develop and commercialize its product candidates. Disruptions in the financial markets in general, and due to public health crises, geopolitical conflicts and economic instability, may make equity and debt financing more difficult to obtain, and may have a material adverse effect on the combined company’s ability to meet its fundraising needs. We cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all.

In the past, litigation, including securities class action litigation, has often followed certain significant business transactions, such as a merger, or the announcement of negative events, such as negative results from clinical trials. These events may also result in investigations by the SEC. The combined company may be exposed to such litigation in connection with the Merger even if no wrongdoing occurred.

Furthermore, the stock market in general, and Nasdaq and biopharmaceutical companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. In the past, companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation. The market price of the combined company’s stock may be volatile, and the combined company may be the target of this type of litigation in the future.

Litigation is usually expensive and diverts management’s attention and resources from other business concerns, which could adversely affect the combined company’s business and cash resources and its ability to achieve the benefits of the Merger or the ultimate value Standard BioTools and Treeline stockholders receive in the Merger.

The combined company may not pay any cash dividends on its capital stock in the foreseeable future, and may choose to retain all of its future earnings, if any, to finance the growth and development of its business. In addition, the terms of any future debt agreements may preclude the combined company from paying dividends. As a result, capital appreciation, if any, of the combined company’s common stock will be the sole source of gain for stockholders for the foreseeable future.

The combined company will incur significant legal, accounting and other expenses as a public company that Treeline did not incur as a private company, including costs associated with public company reporting obligations under the Exchange Act. The combined company’s management team will consist of the executive officers of Treeline prior to the Merger. These executive officers and other personnel will need to devote substantial time to gaining expertise related to public company reporting requirements and compliance with applicable laws and regulations to ensure that the combined company complies with all of these requirements. Operating the combined company as a public company will divert a substantial amount of management’s time from running the business to complying with SEC and Nasdaq requirements. Any changes the combined company makes to comply with these obligations may not be sufficient to allow it to satisfy its obligations as a public company on a timely basis, or at all. These reporting requirements, rules and regulations, coupled with the increase in potential litigation exposure associated with being a public company, could also make it more difficult for the combined company to attract and retain qualified persons to serve on the board of directors or on board committees or to serve as executive officers, or to obtain certain types of insurance, including directors’ and officers’ insurance, on acceptable terms.

As a public company, the combined company will incur significant legal, accounting and other expenses that Treeline did not incur as a private company. The Sarbanes-Oxley Act of 2002 and rules subsequently implemented by the SEC and Nasdaq have imposed various requirements on public companies, including establishment and maintenance of effective disclosure and financial controls and corporate governance practices. The combined company’s management and other personnel will need to devote a substantial amount of time to these compliance initiatives which they have not had to do previously while Treeline was a private company.

Pursuant to Section 404 of the Sarbanes-Oxley Act, the combined company is required to furnish a report by management on its internal control over financial reporting and, depending on the combined company’s status as a “smaller reporting company” or “accelerated filer” following the consummation of the Merger, and depending on the extent to which newly proposed SEC rules are adopted and become applicable to the combined company, an attestation report on internal control over financial reporting may need to be issued by the combined company’s independent registered public accounting firm. Compliance with Section 404 requires companies to dedicate internal resources, potentially engage outside consultants and adopt a detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to improve control processes as appropriate, validate through testing that controls are functioning as documented and implement a continuous reporting and improvement process for internal control over financial reporting.

If the combined company or, if required, its independent registered public accounting firm is not able to conclude within the prescribed timeframe that the company’s internal control over financial reporting is effective as required by Section 404, this could result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of the combined company’s financial statements. In addition, if the combined company is not able to continue to meet these requirements, it may not be able to remain listed on Nasdaq.

The SEC proposed a series of rules in May 2026 which, if adopted, could significantly reduce the compliance burden imposed on U.S. reporting companies, including potentially requiring fewer companies to obtain auditor attestations of their internal control over financial reporting pursuant to Section 404 of the Sarbanes-Oxley Act. However, there is no assurance that any of the SEC’s rule proposals will be adopted, or will be adopted as proposed, or that they would apply to the combined company in whole or in part, if at all. Accordingly, until the SEC adopts final rules, if any, and their applicability to the combined company is analyzed and confirmed, investors should not assume that SEC rulemaking will alleviate any of the compliance burden imposed on the combined company by virtue of being a U.S. reporting company.

Ensuring that the combined company has adequate internal financial and accounting controls and procedures in place so that it can produce accurate financial statements on a timely basis is a costly and time-consuming effort that needs to be re-evaluated frequently. Creation of adequate internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with generally accepted accounting principles. Section 404 of the Sarbanes-Oxley Act will require annual management assessment of the effectiveness of the combined company’s internal control over financial reporting.

Implementing any appropriate changes to Treeline’s internal controls may distract the combined company’s officers and employees, entail substantial costs to modify Treeline’s existing processes, and take significant time to complete. These changes may not, however, be effective in maintaining the adequacy of the combined company’s internal controls, and any failure to maintain that adequacy, or consequent inability to produce accurate financial statements on a timely basis, could increase the combined company’s operating costs and harm its business. In addition, investors’ perceptions that the combined company’s internal controls are inadequate or that the combined company is unable to produce accurate financial statements on a timely basis may harm the combined company’s stock price.

In addition to the requirement to maintain adequate internal control over financial reporting, the combined company will also be required by the Exchange Act to design its disclosure controls and procedures to reasonably assure that information which the combined company discloses in reports it files or submits under the Exchange Act is accumulated and communicated to management, and recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC. Any disclosure controls and procedures or internal controls and procedures, no matter how well-conceived and operated, can provide only reasonable, not absolute, assurance

that the objectives of the control system are met. These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns can occur because of simple error or mistake. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people or by an unauthorized override of the controls. Accordingly, because of the inherent limitations in the control system, misstatements due to error or fraud may occur and not be detected.

The trading market for the combined company’s common stock will be influenced by the research and reports that equity research analysts publish about it and its business. Equity research analysts may elect not to provide research coverage of the combined company’s common stock after the completion of the Merger, and such lack of research coverage may adversely affect the market price of its common stock. In the event it does have equity research analyst coverage, the price of the combined company’s common stock could decline if one or more equity research analysts downgrade its stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of the combined company or fails to publish reports on it regularly, demand for its common stock could decrease, which in turn could cause its stock price or trading volume to decline.

The combined company will have broad discretion over the use of the cash and cash equivalents of the combined company. You may not agree with the combined company’s decisions, and its use of these resources may not yield any return on your investment. The combined company’s failure to apply these resources effectively could compromise its ability to pursue its growth strategy and the combined company might not be able to yield a significant return, if any, on its investment of these resources. You will not have the opportunity to influence its decisions on how to use the combined company’s cash resources.

Following completion of the Merger, the combined company will be susceptible to many of the risks described in the sections herein entitled “Risks Related to Treeline’s Financial Position, Limited Operating History and Need for Additional Capital,” “Risks Related to Treeline’s Product Development, Regulatory Approval, Commercialization and Manufacturing,” “Risks Related to Government Regulation,” “Risks Related to Treeline’s Intellectual Property” and “Risks Related to Treeline’s Business and Operations.” To the extent any of the events in the risks described in these sections occur, the potential benefits of the Merger may not be realized and the results of operations and financial condition of the combined company could be adversely affected in a material way. This could cause the market price of the combined company’s common stock to decline.

The market price of the combined company’s common stock following the Merger could be subject to significant fluctuations. Some of the factors that may cause the market price of the combined company’s common stock to fluctuate include:

Moreover, the stock markets in general have experienced substantial volatility that has often been unrelated to the operating performance of individual companies. These broad market fluctuations may also adversely affect the trading price of the combined company’s common stock. In addition, a recession, depression or other sustained adverse market event could materially and adversely affect the combined company’s business and the value of its common stock. In the past, following periods of volatility in the market price of a company’s securities, stockholders have often instituted class action securities litigation against such companies. Furthermore, market volatility may lead to increased stockholder activism if the combined company experiences a market valuation that activists believe is not reflective of its intrinsic value. Activist campaigns that contest or conflict with the combined company’s strategic direction or seek changes in the composition of its board of directors could have an adverse effect on its operating results, financial condition and cash flows.

Upon completion of the Merger, Standard BioTools, under the new name “Treeline Biosciences Holdings, Inc.,” will be required to meet the initial listing requirements to maintain the listing and continued trading of its shares on Nasdaq. These initial listing requirements are more difficult to achieve than the continued listing requirements, and include a $4.00 minimum bid price requirement at the time of initial listing. Pursuant to the Merger Agreement, Standard BioTools agreed to use its commercially reasonable efforts to cause the shares of

Standard BioTools Common Stock being issued in the Merger to be approved for listing on Nasdaq at or prior to the effective time of the Merger. In order to meet the $4.00 minimum bid price initial listing requirement at the Closing, the Standard BioTools Board intends to effect the Reverse Stock Split, which must be approved by the Standard BioTools stockholders before it can be implemented. However, often a reverse stock split will not result in a trading price for the affected common stock that is proportional to the ratio of the split. Following the Merger, if the combined company is unable to continue to satisfy Nasdaq listing requirements, Nasdaq may notify the combined company that its shares of common stock will not be listed on Nasdaq.

Upon a potential delisting from Nasdaq, if the common stock of the combined company is not then eligible for quotation on another market or exchange, trading of the shares could be conducted in the over-the-counter market or on an electronic bulletin board established for unlisted securities such as the Pink Sheets or the OTC Bulletin Board. In such event, it is likely that there would be significantly less liquidity in the trading of the common stock of the combined company; decreases in institutional and other investor demand for the shares, coverage by securities analysts, market making activity and information available concerning trading prices and volume; and fewer broker dealers willing to execute trades in the common stock of the combined company. Also, it may be difficult for the combined company to raise additional capital if the combined company’s common stock is not listed on a major exchange. The occurrence of any of these events could result in a further decline in the market price of the common stock of the combined company and could have a material adverse effect on the combined company.

Prior to the Merger, there had been no public market for shares of Treeline Capital Stock. An active trading market for the combined company’s shares of common stock may never develop or be sustained. If an active market for the combined company’s common stock does not develop or is not sustained, it may be difficult for the combined company’s stockholders to sell their shares at an attractive price or at all.

If existing securityholders of Standard BioTools and Treeline sell, or indicate an intention to sell, substantial amounts of the combined company’s common stock in the public market after legal restrictions on resale discussed in this proxy statement/prospectus lapse, the trading price of the common stock of the combined company could decline. The combined company is expected to have outstanding a total of approximately     million shares of common stock immediately following the completion of the Merger. Approximately     % of combined company common stock will be freely tradeable upon completion of the Merger and approximately     % of combined company common stock will become available for sale in the public market beginning 180 days after the Closing as a result of the expiration of lock-up agreements between Standard BioTools on the one hand and certain securityholders of Standard BioTools and Treeline on the other hand (and without giving effect to any restrictions on resale under securities laws). In addition, as soon as reasonably practicable following the Closing Date, Standard BioTools will file a registration statement on Form S-8 (or such other appropriate form, if required) with respect to the offering of the shares of the combined company’s common stock issuable upon the exercise of the assumed Treeline Options. The shares of common stock that are subject to outstanding Treeline Options will become eligible for sale in the public market upon the automatic effectiveness of the Form S-8 upon filing. If these shares are sold, the trading price of the combined company’s common stock could decline.

The expiration of lock-up agreements 180 days after the Closing could result in a significant increase in selling pressure on the combined company’s common stock. The market’s anticipation of such sales, even if the sales do not occur, could depress the trading price of the combined company’s common stock prior to the expiration of the lock-up period.

This proxy statement/prospectus also registers for resale approximately 1.5 billion shares of Standard BioTools Common Stock held by the Selling Securityholders. These shares remain subject to the lock-up agreements described above and may not be sold until those agreements expire (subject to certain exceptions set forth in the applicable lock-up agreements). However, because the shares will be registered for resale pursuant to the registration statement on Form S-4 of which this proxy statement/prospectus and the resale prospectus form a part, once the lock-up period expires, the Selling Securityholders will be able to sell such shares immediately, without any further registration or compliance with the volume and other limitations of Rule 144 under the Securities Act that would otherwise apply to restricted securities. As a result, expiration of the lock-up period could produce a more sudden

increase in the supply of shares available for sale than would otherwise be the case, which could cause the market price of the combined company’s common stock to decline. We have no control over whether or when the Selling Securityholders will sell their shares following expiration of the lock-up period. See “Selling Securityholders” and “Plan of Distribution” in the resale prospectus also included in the registration statement on Form S-4 of which this proxy statement/prospectus forms a part.

This proxy statement/prospectus also registers for resale shares of Standard BioTools Common Stock held by the Selling Securityholders. Subject to the lock-up agreements described herein, we have no control over when or whether the Selling Securityholders will sell their shares or the prices at which they choose to sell. The Selling Securityholders may sell their shares at any time or from time to time in one or more types of transactions (which may include block transactions) at then-prevailing market prices, at prices related to prevailing market prices, in negotiated transactions, or otherwise as described in the “Plan of Distribution” in the resale prospectus also included in the registration statement on Form S-4 of which this proxy statement/prospectus forms a part. Sales by the Selling Securityholders may occur at times when, in our judgment, it would not be advisable for us or our stockholders for such sales to be made, such as during periods of lower trading volume, during periods when we may be in possession of material nonpublic information (which the Selling Securityholders would not be required to delay sales for), or when market conditions may otherwise be unfavorable. Sales by the Selling Securityholders, or the perception that such sales may occur, could depress the market price of Standard BioTools Common Stock and impair our ability to raise capital through the sale of additional equity securities.

Upon completion of the Merger, former Treeline stockholders are expected to own approximately 84% of the outstanding common stock of the combined company on a fully diluted basis, and former Standard BioTools stockholders are expected to own approximately 16% of the outstanding common stock of the combined company on a fully diluted basis. In addition, the board of directors of the combined company is expected to consist of 12 members, with 10 members designated by Treeline and two members designated by Standard BioTools. As a result, former Treeline stockholders and the directors designated by Treeline will have the ability to control the outcome of matters submitted to the stockholders of the combined company for approval, including the election of directors and the approval of significant corporate transactions. The interests of former Treeline stockholders may not always coincide with the interests of former Standard BioTools stockholders. This concentration of ownership could delay, defer, or prevent a change in control of the combined company, deprive stockholders of an opportunity to receive a premium for their shares as part of a sale of the combined company, and could ultimately affect the market price of the combined company’s common stock.

We believe that based on Standard BioTools’ assets and operations, on both an actual and a pro forma basis after giving effect to the Merger, Standard BioTools is not a “shell company” under SEC rules and will not be a “shell company” at Closing. However, if Standard BioTools were to be classified as a “shell company” under SEC rules, such status could affect the combined company in several ways, including that:

The foregoing SEC requirements will increase the combined company’s time and cost of raising capital and complying with securities laws. These limitations could also adversely affect the liquidity of the combined company’s securities and could limit the combined company’s ability to offer equity compensation to attract and retain employees.

Prior to the Merger, Standard BioTools was a life sciences tools company focused on mass cytometry and microfluidics technologies. Following the Merger, the combined company’s primary focus will be on Treeline’s clinical-stage biopharmaceutical programs in oncology, neurology and immunology. This significant change in business focus may result in a loss of interest from investors who invested in Standard BioTools for exposure to the life sciences tools industry. In addition, equity research analysts who currently cover Standard BioTools’ stock may elect to discontinue coverage following the Merger, and the combined company may need to establish relationships with new analysts who cover the biopharmaceutical industry. The lack of continuity in analyst coverage could adversely affect trading volume and the market price of the combined company’s common stock. Furthermore, existing stockholders of Standard BioTools, including certain institutional investors, may have investment mandates or portfolio guidelines that do not permit investment in clinical-stage biopharmaceutical companies, which could result in selling pressure following the Merger.

The Mass Cytometry Purchase Agreement contains a number of conditions that must be satisfied or waived (to the extent permitted by applicable law) in order to consummate the Mass Cytometry Divestiture, some of which are not within Standard BioTools’ control. These conditions include, among others, the approval of the Mass Cytometry Divestiture Proposal by the Standard BioTools stockholders and the substantially concurrent consummation of the Merger and the other Merger Transactions.

Any failure to satisfy or, to the extent permitted by applicable law, waive these required closing conditions may prevent, delay or otherwise materially adversely affect the consummation of the Mass Cytometry Divestiture. Standard BioTools cannot predict with certainty whether or when any of the required conditions will be satisfied or, to the extent permitted by applicable law, waived, and cannot assure you that Standard BioTools will be able to

successfully consummate the Mass Cytometry Divestiture as currently contemplated under the Mass Cytometry Purchase Agreement or at all. For additional information regarding the conditions to the Mass Cytometry Divestiture, see “The Mass Cytometry Purchase Agreement — Conditions to the Mass Cytometry Divestiture Closing” beginning on page 267 of this proxy statement/prospectus.

In addition, the Mass Cytometry Divestiture might not be consummated because Multiplex Bio or Standard BioTools may elect to terminate the Mass Cytometry Purchase Agreement in certain circumstances. Upon termination of the Mass Cytometry Purchase Agreement under specified circumstances, including if Multiplex Bio terminates the Mass Cytometry Purchase Agreement due to a change in the Standard BioTools Board recommendation in favor of the Mass Cytometry Divestiture, Standard BioTools will be required to make a payment to Multiplex Bio equal to $1.0 million in cash. Standard BioTools also will be required to reimburse Multiplex Bio's reasonable and documented out-of-pocket fees in connection with the Mass Cytometry Divestiture, up to a maximum of $125,000 if the Mass Cytometry Divestiture has not closed by December 31, 2026, and up to an additional $125,000 (for an aggregate of $250,000) if the Mass Cytometry Divestiture has not closed by March 31, 2027. Any expense reimbursement paid is credited against the termination fee, and the termination fee is not payable on more than one occasion. See “The Mass Cytometry Purchase Agreement — Termination” beginning on page 278 of this proxy statement/prospectus.

While the Mass Cytometry Divestiture is pending, the uncertainty regarding the mass cytometry business’ future could have a negative impact on the mass cytometry business. Therefore, Standard BioTools’ current or potential business partners may decide to delay, defer or cancel entering into new business arrangements with the mass cytometry business pending consummation of the Mass Cytometry Divestiture, and employees of the mass cytometry business may be unsure regarding their future. The occurrence of these events individually or in combination could materially and adversely affect the mass cytometry business’ business, financial condition and results of operations.

The Mass Cytometry Divestiture is subject to various closing conditions including, among others, the approval of the Mass Cytometry Divestiture by Standard BioTools’ stockholders and the substantially concurrent consummation of the Merger. Standard BioTools cannot control these conditions and cannot assure you that they will be satisfied. If the Mass Cytometry Divestiture is not consummated, Standard BioTools may be subject to a number of risks, including the following:

The occurrence of any of these events individually or in combination could materially and adversely affect Standard BioTools’ business, financial condition and results of operations, which could cause the market value of Standard BioTools’ common stock to decline.

The closing of the Merger and the other Merger Transactions is not conditioned on the closing of the Mass Cytometry Divestiture. If Standard BioTools fails to consummate the Mass Cytometry Divestiture, the Merger may still proceed, provided that the closing conditions contained in the Merger Agreement are satisfied or waived. In the event that the Mass Cytometry Divestiture does not close prior to the consummation of the Merger and the Mass Cytometry Purchase Agreement is terminated, the Merger Agreement provides that Standard BioTools shall continue to use its commercially reasonable efforts to effect the sale, license, transfer, disposition, divestiture or other monetization of the Legacy Businesses. If Standard BioTools has not entered into a definitive agreement for the disposition of any portion of the Legacy Businesses on or before the date the registration statement on Form S-4 of which this proxy statement/prospectus forms a part is declared effective under the Securities Act, Standard BioTools is required to commence mutually agreed wind-down activities with respect to that portion of the Legacy Businesses. The occurrence of these events may result in the combined company continuing to own all or a portion of the Legacy Businesses following the closing of the Merger, which could cause the combined company to incur unanticipated costs and expenses in connection with continued ownership and pursuit of an alternative disposition of such portion of the Legacy Businesses.

Pursuant to the Mass Cytometry Purchase Agreement, following the Mass Cytometry Divestiture Closing, Standard BioTools may receive additional consideration of $5 million if Multiplex Bio consummates a qualifying sale transaction for consideration in excess of a specified dollar threshold within ten years of the Mass Cytometry Divestiture Closing. There can be no assurance that Multiplex Bio will consummate a qualifying sale transaction or that, if it does, that it will pay Standard BioTools the required additional consideration of $5 million.

Additionally, Multiplex Bio is required to use reasonable best efforts to obtain a senior secured working capital loan facility, available to it after the Mass Cytometry Divestiture Closing on terms reasonably satisfactory to Standard BioTools, and if Multiplex Bio is unable to obtain such financing prior to the Mass Cytometry Divestiture Closing despite using such efforts, Standard BioTools must provide Multiplex Bio a working capital loan at the Mass Cytometry Divestiture Closing in an amount of up to $10 million. There can be no assurance that Multiplex Bio will be able to obtain appropriate financing prior to the Mass Cytometry Divestiture Closing, and in such event Standard BioTools may be required to provide the working capital loan on behalf of Multiplex Bio, which could have a negative impact on Standard BioTools’ business, financial condition, results of operations and prospects.

Treeline is an early clinical-stage biopharmaceutical company with a limited operating history. Treeline commenced operations in 2021, has no products approved for commercial sale and has never generated any revenue. Drug development is a highly speculative undertaking and involves a substantial degree of risk. It entails substantial upfront capital expenditures and significant risk that any product candidate will fail to demonstrate adequate efficacy or an acceptable safety profile, gain regulatory approval or become commercially viable. To date, Treeline has devoted substantially all of its resources to identifying, acquiring and developing its product candidates and technologies, including TLN-121, TLN-254, TLN-372 and TLN-499, building its pipeline, conducting preclinical studies and early-stage clinical trials, organizing and staffing its company, business planning, establishing and maintaining its intellectual property portfolio, establishing arrangements with third parties for the manufacture of its product candidates, raising capital and providing general and administrative support for these operations.

To date, Treeline has funded its operations primarily with proceeds from sales of its convertible preferred stock. From inception through June 30, 2026, it received an aggregate of $1.2 billion in net proceeds from sales of its convertible preferred stock.

Treeline has not yet demonstrated an ability to successfully complete any clinical trials, including for TLN-121, TLN-254, TLN-372 and TLN-499, obtain regulatory approvals, manufacture a commercial-scale product or arrange

for a third party to do so on its behalf, or conduct sales and marketing activities necessary for successful product commercialization. As a result, it may be more difficult for investors to accurately predict its likelihood of success and viability than it could be if it had a longer operating history.

In addition, Treeline may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown factors and risks frequently experienced by clinical-stage biopharmaceutical companies developing therapies for oncology and other serious diseases. Treeline also may need to transition from a company with a research and development focus to a company capable of supporting commercial activities. Treeline has not yet demonstrated an ability to successfully overcome such risks and difficulties, or to make such a transition. If Treeline does not adequately address these risks and difficulties or successfully make such a transition, its business will suffer.

Treeline has incurred significant operating losses since its inception, has not generated any product revenue to date and has financed its operations primarily through private placements of its convertible preferred stock. For the six months ended June 30, 2026 and for the years ended December 31, 2025 and 2024, it reported a net loss of $105.5 million, $162.5 million and $162.5 million, respectively. It had an accumulated deficit of $706.8 million as of June 30, 2026. There is no assurance that Treeline will obtain financing from other sources, or that it will be able to obtain such financing on favorable terms, if at all. Substantially all of Treeline’s losses have resulted from expenses incurred in connection with operations identifying, acquiring and developing its product candidates and technologies, including TLN-121, TLN-254, TLN-372 and TLN-499, and other potential or future product candidates, building its pipeline, conducting preclinical studies and early-stage clinical trials, organizing and staffing its company, business planning, establishing and maintaining its intellectual property portfolio, establishing arrangements with third parties for the manufacture of its product candidates, raising capital and providing general and administrative support for these operations. Treeline expects to incur increasing levels of operating losses for the foreseeable future as it continues its research and development activities, continues its ongoing clinical trials, initiates additional clinical trials, seeks to expand its product pipeline and clinical applications, seeks regulatory approval for its current and future product candidates, and invests in its organization. Treeline’s prior losses have had, and combined with expected future losses will continue to have, an adverse effect on its stockholders’ equity and working capital. Treeline expects its research and development expenses to significantly increase as it advances TLN-121, TLN-254, TLN-372 and TLN-499 through clinical trials, advances other earlier-stage product candidates and identifies new product candidates. In addition, if Treeline obtains regulatory approval for TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates, it will incur significant sales, marketing, manufacturing and distribution expenses in connection with the commercialization of TLN-121, TLN-254, TLN-372 and TLN-499 or any other product candidates. Furthermore, upon the completion of the Merger, Treeline expects to incur additional costs associated with operating as a public company that it did not incur as a private company. Treeline may never succeed in these activities and, even if it does, it may never generate any revenue or revenue that is significant enough to achieve profitability.

As a result, Treeline expects to continue to incur significant and increasing net losses for the foreseeable future. Because of the numerous risks and uncertainties associated with developing therapeutic products, Treeline is unable to predict the extent of any future losses or when it will become profitable, if at all. To become and remain profitable, Treeline must succeed in discovering, developing, obtaining regulatory approvals for, and eventually commercializing products that generate significant revenue. Treeline is only in the preliminary stages of these activities.

Even if Treeline does become profitable, it may not be able to sustain or increase its profitability on a quarterly or annual basis. In addition, Treeline expects its financial condition and operating results to fluctuate significantly from quarter-to-quarter and year-to-year due to a variety of factors, many of which are beyond its control. Accordingly, you should not rely on the results of any quarterly or annual periods as indications of future operating performance. If Treeline fails to become and remain profitable, there may be an adverse effect on the value of Treeline which could impair its ability to raise capital, expand its business, maintain its research and development efforts, diversify its product candidate pipeline, achieve its strategic objectives or even continue its operations. A decline in the value of Treeline could also cause you to lose all or part of your investment.

Developing product candidates, including conducting preclinical studies and clinical trials, is a very time-consuming, expensive and uncertain process that takes years to complete. Treeline’s operations have consumed substantial amounts of cash since inception, and Treeline expects its expenses to increase substantially in connection with its ongoing activities, particularly as Treeline advances TLN-121, TLN-254, TLN-372 and TLN-499 and other potential or future product candidates through preclinical and clinical development. Treeline expects increased expenses as it continues its research and development, continues its ongoing clinical trials, initiates additional clinical trials, seeks to expand its product pipeline and clinical applications, seeks regulatory approval for its current and future product candidates, and invests in its organization. In addition, if Treeline obtains regulatory approval for any of its product candidates, it expects to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. Furthermore, upon the completion of the Merger, Treeline expects to incur additional costs associated with operating as a public company that it did not incur as a private company. Accordingly, it will need to obtain substantial additional funding in connection with its continuing operations.

Based on Treeline’s current operating plan, it believes its existing cash and cash equivalents as of June 30, 2026, along with the net cash held by Standard BioTools upon consummation of the Merger, will enable Treeline to fund Treeline’s operations into 2029. Treeline has based this estimate on assumptions that may prove to be wrong, and Treeline could use its capital resources sooner than it currently expects. Changes beyond Treeline’s control may occur that would cause it to use its available capital before that time, including changes in and progress of its drug development activities and changes in regulations. Treeline’s future capital requirements will be dependent on many factors, including:

Even if the Merger is successful, Treeline will require additional capital to complete its planned preclinical studies and clinical trials for its current and other potential or future product candidates to obtain regulatory approval, and Treeline anticipates needing to raise additional capital to complete the development of, and eventually commercialize, its product candidates, if approved. Adequate additional financing may not be available to Treeline on favorable terms, or at all. Treeline’s ability to raise additional funds will be dependent on financial, economic and market conditions, geopolitical issues and other factors, over which Treeline may have limited or no control. In addition, Treeline may seek additional capital due to favorable market conditions or strategic considerations even if it believes it has sufficient funds for its current or future operating plans. If adequate funds are not available on commercially acceptable terms when needed, Treeline may be forced to delay, reduce or terminate the development or commercialization, if approved, of all or part of its research programs or product candidates or it may be unable to take advantage of future business opportunities, including pursuing new in-licenses and acquisitions. Furthermore, any additional capital-raising efforts may divert Treeline’s management from their day-to-day activities, which may adversely affect Treeline’s ability to develop and commercialize its current and other product candidates, if approved. Changing circumstances, some of which may be beyond its control, could cause it to consume capital significantly faster than it currently anticipates, and it may need to seek additional funds sooner than planned.

Treeline’s failure to raise capital as and when needed or on acceptable terms could significantly harm its business, financial condition, results of operations and prospects, and Treeline may have to delay, reduce the scope of, suspend or eliminate one or more of its research or drug development programs, preclinical studies, clinical trials or future commercialization efforts.

Treeline’s future success is highly dependent on Treeline’s ability to timely complete successful preclinical studies and clinical trials, obtain regulatory approval for, and then successfully commercialize, its product candidates. Treeline’s most advanced product candidates, TLN-121, TLN-254, TLN-372 and TLN-499, are in Phase 1 clinical development. Treeline currently has no products that are approved for sale in any jurisdiction. Treeline has invested substantially all of its efforts and financial resources in TLN-121, TLN-254, TLN-372 and TLN-499 and its other potential or future product candidates, and in conducting preclinical studies and clinical trials. There can be no assurance that TLN-121, TLN-254, TLN-372 and TLN-499 or any other product candidates Treeline develops will achieve success in their clinical trials or obtain regulatory approval. In the future, Treeline may also become dependent on other product candidates that it may develop or acquire; however, given Treeline’s early stage of development, it may be several years, if at all, before it has demonstrated the safety and efficacy of a treatment sufficient to warrant approval for commercialization.

Treeline’s ability to generate product revenue, which it does not expect will occur for many years, if ever, will be heavily dependent on the successful development and eventual commercialization of its current product candidates, and the development of potential or future product candidates. The success of TLN-121, TLN-254, TLN-372 and TLN-499 and other potential or future product candidates will be dependent on several factors, including the following:

Many of these factors are beyond Treeline’s control, and it is possible that none of Treeline’s product candidates will ever obtain regulatory approval even if it expends substantial time and resources seeking such approval. If Treeline does not achieve one or more of these factors in a timely manner or at all, it could experience significant delays or an inability to successfully commercialize its product candidates, which would materially harm its business. For example, Treeline’s business could be harmed if results of its ongoing clinical trials of TLN-121, TLN-254 and TLN-372 show unexpected adverse events or a lack of efficacy in the indications Treeline intends to treat, do not meet the clinical endpoints or if Treeline experiences other regulatory or developmental issues.

TLN-121, TLN-254, TLN-372 and TLN-499 are in Phase 1 clinical development and represent Treeline’s clinical-stage product candidates. Treeline’s pipeline also includes potential or future product candidates in preclinical and discovery-stage development. The risk of failure is high for early clinical-stage product candidates. It is impossible to predict when or if Treeline’s product candidates or any future product candidates will receive regulatory approval. To obtain the requisite regulatory approvals to commercialize any product candidate, Treeline must demonstrate through extensive preclinical studies and lengthy, complex and expensive clinical trials that Treeline’s product candidates are safe and effective. Clinical testing can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time during the preclinical study and clinical trial processes. The results of preclinical studies and early clinical trials of Treeline’s product candidates or any future product candidates, or a competitor’s product candidate in the same class, may not be predictive of the results of later-stage clinical trials. Interim, topline or preliminary results of a clinical trial are not necessarily indicative of final results. Treeline may be unable to establish benefit on clinical endpoints that applicable regulatory authorities would consider clinically meaningful, and a clinical trial can fail at any stage of testing. Differences in trial design between early-stage clinical trials and later-stage clinical trials make it difficult to extrapolate the results of earlier clinical trials to later clinical trials. Moreover, clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in clinical trials have nonetheless failed to obtain regulatory approval of their products. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or to unfavorable safety profiles, notwithstanding promising results in earlier trials. Most product candidates that commence clinical trials are never approved as products and there can be no assurance that any of Treeline’s future clinical trials will ultimately be successful or support clinical development of Treeline’s product candidates or any future product candidates.

Additionally, Treeline’s current clinical trials utilize, and future clinical trials may utilize, an open-label trial design. An open-label clinical trial is one where both the patient and investigator know whether the patient is receiving the investigational product candidate or either an existing approved drug or placebo. Most typically, open-label clinical trials test only the investigational product candidate and sometimes may do so at different dose levels. Open-label clinical trials are subject to various limitations that may exaggerate any therapeutic effect as patients in open-label clinical trials are aware when they are receiving treatment. Open-label clinical trials may be subject to a patient bias where patients perceive their symptoms to have improved merely due to their awareness of receiving an experimental treatment. In addition, open-label clinical trials may be subject to an investigator bias where those assessing and reviewing the physiological outcomes of the clinical trials are aware of which patients have received treatment and may interpret the information of the treated group more favorably given this knowledge. The results from an open-label trial of Treeline’s product candidates may not be predictive of future clinical trial results when studied in a controlled environment with a placebo or active control.

Treeline may experience delays in initiating or completing clinical trials. Treeline also may experience numerous unforeseen events during, or as a result of, any future clinical trials that could delay or prevent Treeline’s ability to receive regulatory approval or commercialize Treeline’s product candidates or any future product candidates, including:

Treeline could also encounter delays if a clinical trial is suspended or terminated by Treeline, the IRBs overseeing the institutions in which such trials are being conducted, or the FDA or other comparable regulatory authorities, or if a clinical trial is recommended for suspension or termination by the Data Safety Monitoring Board (“DSMB”) for such trial. A suspension or termination may be imposed due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements, including the FDA’s GCP regulations, or Treeline’s clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other comparable foreign regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product or treatment, failure to establish or achieve clinically meaningful trial endpoints, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. For example, in June 2026, the FDA placed a partial clinical hold on Treeline’s clinical trials evaluating treatment with TLN-254. The FDA removed the partial clinical hold on TLN-254 on July 23, 2026. This hold impacted the Phase 1 TLN-254 monotherapy trial in

patients with relapsed or refractory peripheral T-cell lymphoma, and a separate Phase 1 trial that includes a treatment arm of TLN-254 in combination with TLN-121 in patients with non-Hodgkin’s lymphoma. This hold was initiated following FDA’s May 2026 announcement of an increased rate of hematologic second primary malignancies in patients receiving tazemetostat for relapsed or refractory follicular lymphoma in a clinical trial. Following this announcement, the sponsor of tazemetostat discontinued its clinical trials of tazemetostat and withdrew the product from the market for its approved indications. Tazemetostat is in the same drug class as TLN-254. Adverse safety findings involving similar product candidates or approved products to Treeline’s product candidates that are developed or commercialized by third parties could likewise result in additional clinical holds, delays or additional regulatory requirements for Treeline’s product candidates, even where Treeline’s own trials have not raised the same or similar level of concerns. Clinical studies may also be delayed or terminated as a result of ambiguous or negative interim results. Many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of Treeline’s product candidates or any future product candidates. Further, the FDA or other comparable foreign regulatory authorities may disagree with Treeline’s clinical trial design and Treeline’s interpretation of data from clinical trials, or may change the requirements for approval even after they have reviewed and commented on the design for Treeline’s clinical trials.

Treeline cannot predict with any certainty the schedule for commencement and completion of future clinical trials. Further, conducting clinical trials in foreign countries, as Treeline is currently doing and may do in the future for Treeline’s product candidates, presents additional risks that may delay completion of Treeline’s clinical trials. These risks include the failure of enrolled patients in foreign countries to adhere to clinical protocol as a result of differences in healthcare services or cultural customs, managing additional administrative burdens associated with foreign regulatory schemes, as well as political and economic risks relevant to such foreign countries. If Treeline is required to conduct additional clinical trials or other testing of Treeline’s current or future product candidates beyond those that Treeline currently contemplates, if Treeline is unable to successfully complete clinical trials of Treeline’s current or future product candidates or other testing in a timely manner, if the results of these trials or tests are not positive or are only modestly positive or if there are safety concerns, Treeline may incur unplanned costs, or be delayed in seeking and obtaining regulatory approval. Additionally, if Treeline receives such approval at all, or receives more limited or restrictive regulatory approval, or if Treeline becomes subject to additional post-marketing testing requirements or has the product removed from the market after obtaining regulatory approval, Treeline could incur significant costs and limitations which may adversely affect Treeline’s financial condition and operating results.

Additionally, if the results of Treeline’s clinical trials are inconclusive or if there are safety concerns or serious adverse events (“SAEs”) associated with Treeline’s product candidates, Treeline may:

Treeline’s drug development costs may also increase if Treeline experiences delays in testing or obtaining regulatory approvals. Also, delays in obtaining regulatory approval may increase commercialization costs if the competitive environment becomes more intense prior to market entry. Treeline does not know whether any of Treeline’s preclinical studies or clinical trials will begin as planned, need to be restructured or be completed on schedule, if at all.

Moreover, principal investigators for Treeline’s clinical trials may serve as scientific advisors or consultants to Treeline from time to time and receive compensation in connection with such services. Under certain circumstances, Treeline may be required to report some of these relationships to the FDA or comparable foreign regulatory authorities. The FDA or comparable foreign regulatory authority may conclude that a financial relationship between Treeline and a principal investigator has created a conflict of interest or otherwise affected interpretation of the study. The FDA or comparable foreign regulatory authority may therefore question the integrity of the data generated at the applicable clinical trial site and the utility of the clinical trial itself may be jeopardized. This could result in a delay in approval, or rejection, of Treeline’s marketing applications by the FDA or comparable foreign regulatory authority, as the case may be, and may ultimately lead to the denial of regulatory approval of one or more of Treeline’s product candidates.

Treeline may make formulation or manufacturing changes to Treeline’s product candidates, in which case Treeline may need to conduct additional preclinical or clinical studies to bridge Treeline’s modified product candidates to earlier versions. If Treeline experiences delays in the commencement or completion of Treeline’s clinical trials, or if Treeline terminates a clinical trial prior to completion, the commercial prospects of Treeline’s current or any future product candidates could be negatively impacted, and Treeline’s ability to generate revenues from Treeline’s current or future product candidates may be delayed or eliminated entirely.

TLN-254, one of Treeline’s clinical-stage product candidates, is an oral inhibitor of EZH2 that Treeline in-licensed from Jiangsu Hengrui Pharmaceuticals Co., Ltd. (“Hengrui”). In March 2026, another EZH2 inhibitor, tazemetostat (formerly marketed as Tazverik), was voluntarily withdrawn from all markets, including the United States, after an independent data monitoring committee identified cases of secondary hematologic malignancies in a clinical trial combining tazemetostat with lenalidomide and rituximab (18 cases, 5.7% hematologic secondary malignancy) compared to lenalidomide and rituximab alone (0 cases of hematologic second primary malignancy) in patients with relapsed or refractory follicular lymphoma, leading its sponsor to also discontinue clinical development. In June 2026, the FDA placed a partial clinical hold on Treeline’s clinical trials evaluating treatment with TLN-254. This hold impacted the Phase 1 TLN-254 monotherapy trial in patients with relapsed or refractory peripheral T-cell lymphoma, and a separate Phase 1 trial that includes a treatment arm of TLN-254 in combination with TLN-121 in patients with non-Hodgkin’s lymphoma. The FDA removed the partial clinical hold on TLN-254 on July 23, 2026. As a result of these developments, the FDA and comparable foreign regulatory authorities may apply heightened scrutiny to product candidates that inhibit EZH2, including TLN-254, and may require additional preclinical or clinical data, impose additional clinical holds, labeling restrictions or monitoring requirements, narrow the patient populations that may be studied or treated, or decline to approve TLN-254 (including for use in combination with TLN-121). Any of these outcomes, or any actual or perceived safety concerns associated with the EZH2 inhibitor class generally, could delay, limit or prevent the development, regulatory approval or commercialization of TLN-254, could reduce its commercial potential if approved, and could require Treeline to commit additional resources, any of which could materially and adversely affect Treeline’s business, financial condition, results of operations and prospects. Because Treeline in-licensed TLN-254 from Hengrui, Treeline may also have limited control over certain development, regulatory and manufacturing decisions for the program and depends on Hengrui’s continued performance under Treeline’s license agreement with Hengrui (the “Hengrui License Agreement”).

Treeline does not independently conduct all aspects of its discovery and preclinical studies, manufacturing, and clinical trials. It relies, and expects to continue to rely, on third parties such as CROs, contract development and manufacturing organizations (“CDMOs”), consultants, clinical investigators, clinical trial sites, collaborators and other independent contractors to conduct, supervise or monitor its preclinical studies and clinical trials, and to conduct manufacturing and it has limited control over their activities. The timing of the initiation and completion of

these activities will therefore be partially controlled by such third parties and may result in delays to Treeline’s development programs. Specifically, Treeline expects CROs, independent clinical investigators and consultants to play a significant role in the conduct of these studies and trials and the subsequent collection and analysis of data. However, these third parties are not Treeline’s employees, may have competing priorities and commitments to other entities, and may not devote sufficient time or resources to Treeline’s programs or meet expected deadlines. In addition, Treeline has less control over the timing, quality and other aspects of discovery and preclinical studies, manufacturing and clinical trials than it would if it were to conduct these activities on its own. Nevertheless, Treeline is responsible for ensuring that these third parties comply with current Good Manufacturing Practices (“cGMPs”), GCP and Good Laboratory Practice requirements and other applicable regulations, and if they fail to do so, or fail to conduct a study or trial in accordance with the applicable protocol, or fail to be diligent, careful or timely, the data generated may be deemed unreliable and Treeline may be required to repeat, extend or delay its studies or trials or conduct additional ones. Treeline cannot make any assurances that, upon inspection, the FDA will determine that its clinical trials comply with GCPs. Treeline’s failure or the failure of third parties on whom Treeline relies to comply with these regulations may require Treeline to stop and/or repeat clinical trials, which would delay the marketing authorization process or prevent marketing authorization.

There is no guarantee that any such CROs, clinical trial investigators, clinical trial sites or other third parties on which Treeline relies will devote adequate time and resources to Treeline’s development activities or perform as contractually required. In addition, these third parties may be subject to macroeconomic conditions, such as staffing shortages and supply chain or inflationary pressures that limit their ability to achieve anticipated timelines or result in a greater cost to Treeline. For example, Treeline is aware of recurrent shortages of non-human primates available for preclinical studies and although that is not expected to impact Treeline’s current business, if Treeline begins new product development programs Treeline could be subject to longer development times or difficulty completing necessary research.

Furthermore, these third parties may also have relationships with other entities, some of which may be Treeline’s competitors for whom they may also be conducting clinical trials or other therapeutic candidate development activities that could harm Treeline’s competitive position.

If any of these third parties terminate their engagement with Treeline, perform inadequately, experience their own regulatory, financial or operational difficulties, or fail to meet applicable standards, Treeline’s business could be adversely affected, research and development programs may be delayed or impaired, its costs may increase, and its ability to obtain regulatory approval for and to commercialize its product candidates may be impaired.

From time to time, Treeline may support investigator-initiated or investigator-sponsored clinical trials of its product candidates that are conducted by third-party investigators or institutions over whose design, conduct, data collection and regulatory compliance Treeline has limited control. Adverse events, protocol deviations, non-compliance with applicable regulatory requirements or unfavorable or inconsistent results arising in any such trial could delay, limit or otherwise harm the clinical development or regulatory approval of Treeline’s product candidates, even though Treeline would not control these trials. Treeline may also have obligations to collect, evaluate and report to the FDA or comparable foreign regulatory authorities safety information arising from any such trials. Serious adverse events or other safety findings in any such trial could be attributed to Treeline’s product candidates, could result in a clinical hold or other regulatory action affecting Treeline’s own clinical trials, and could harm the reputation of, or market perception regarding, the affected product candidate.

Patient enrollment, a significant factor in the timing and completion of clinical trials, is affected by many factors including the size and nature of the patient population, the number and location of enrolling clinical sites engaged by Treeline, the proximity of patients to clinical sites, the eligibility and exclusion criteria for the trial, the design of the clinical trial, the inability to obtain and maintain patient consents, the risk that enrolled participants will drop out before completion, competing clinical trials, and clinicians’ and patients’ perceptions as to the potential advantages of the product candidate being studied in relation to other available therapies, including any new drugs or therapeutic biologics, including those being developed by Treeline’s competitors, that may be approved for the indications being investigated by Treeline, and patients’ inability to complete treatment due to illness or other events. The patient populations for Treeline’s product candidates are limited to those with non-Hodgkin’s lymphomas, T-cell lymphoma, and KRAS mutant solid tumors, which are substantially smaller than the general treated cancer population, and certain of these cancers may have limited prevalence. Clinical sites participating in

Treeline-sponsored clinical trials will need to screen and identify these patients, including through the evaluation of patient biopsies and blood samples that may require the use of companion diagnostic tests, and it may be difficult to identify and enroll a sufficient number of eligible patients. In addition, some of Treeline’s competitors currently have ongoing clinical trials for product candidates that would seek to enroll the same patients as Treeline’s product candidates, and patients who would otherwise be eligible for Treeline’s clinical trials may instead enroll in clinical trials of Treeline’s competitors’ product candidates.

Furthermore, Treeline expects to rely on its collaborators, CROs and clinical trial sites to ensure the proper and timely conduct of its future clinical trials, including the patient enrollment process, and Treeline has limited influence over their performance. Additionally, Treeline could encounter delays if treating physicians face unresolved ethical issues associated with enrolling patients in current or planned clinical trials of Treeline’s current or any future product candidates in lieu of prescribing existing treatments that have established safety and efficacy profiles.

Treeline may not be able to initiate or continue its ongoing or planned clinical trials for its current or future product candidates if it is unable to enroll a sufficient number of eligible patients to participate in these trials as required by the FDA or comparable foreign regulatory authorities. Treeline cannot be certain (i) how many patients will meet its criteria for inclusion in its clinical trials, (ii) that the number of patients enrolled in each program will suffice for marketing authorization or (iii) whether the indication targeted will be included in the approved product labeling. If Treeline’s strategies for patient identification and enrollment prove unsuccessful, it may have difficulty enrolling or maintaining patients appropriate for Treeline’s product candidates. Patient enrollment is also affected by other factors, including:

If Treeline is unable to enroll a sufficient number of patients for its clinical trials, it would result in significant delays or might require it to abandon one or more clinical trials altogether. Even if Treeline is able to enroll a sufficient number of patients for its clinical trials, it may have difficulty retaining patients in its clinical trials. For example, if patients are receiving placebo in a clinical trial, those patients may perceive that they are not receiving the product candidate being tested, and they may decide to withdraw from that clinical trial to pursue other

alternative therapies rather than continue the trial with the perception that they are receiving placebo. Enrollment delays in Treeline’s clinical trials may result in increased development costs for TLN-121, TLN-254, TLN-372 and TLN-499, or other potential or future product candidates, slow down or halt Treeline’s product candidate development and approval process and jeopardize its ability to seek and obtain the regulatory approval required to commence product sales and to generate revenue, if needed.

There may be treatment-related SAEs or unexpected serious adverse reactions suspected to be associated with the use of TLN-121, TLN-254, TLN-372 and TLN-499 or other potential or future product candidates. Treeline’s clinical trials may reveal significant adverse events not seen in its preclinical studies or prior clinical trials and may result in a safety or tolerability profile that could delay or prevent regulatory approval or market acceptance of TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates. Undesirable or clinically unmanageable side effects observed in Treeline’s clinical trials for its product candidates or of a competitor developing similar product candidates could occur and cause it or regulatory authorities to interrupt, delay or halt Treeline’s clinical trials (such as the previous partial clinical hold of Treeline’s TLN-254 clinical trials with respect to the cohorts receiving TLN-254 as a monotherapy or in combination with TLN-121, which was issued by the FDA in June 2026 but removed by the FDA on July 23, 2026) and could result in more restrictive labeling than anticipated or the delay or denial of regulatory approval by the FDA or comparable foreign regulatory authorities. If additional adverse events, SAEs or other side effects are observed in any of Treeline’s or its competitor’s clinical trials that are atypical of, or more severe than, the known side effects of the respective class of agents that each of Treeline’s product candidates is a part of, or other products in development for the same indications, or the current standard of care, Treeline may have difficulty recruiting participants to its clinical trials, participants may drop out of its trials, or Treeline may be required to abandon those trials or its development efforts of one or more product candidates altogether. Furthermore, clinical trials by their nature utilize a sample of the potential patient population. With a limited number of subjects and limited duration of exposure, rare and severe side effects of Treeline’s product candidates or those of its competitors may only be uncovered with a significantly larger number of patients exposed to the drug. Undesirable or clinically unmanageable side effects observed in Treeline’s clinical trials for its product candidates could also occur following discontinuation of TLN-121, TLN-254, TLN-372 and TLN-499, or other product candidates with sufficient recovery periods, and Treeline will need to monitor the severity and duration of side effects in its clinical trials. If such effects are more severe, less reversible than Treeline expects or not reversible at all, it may decide or be required to perform additional studies or to halt or delay further clinical or preclinical development of TLN-121, TLN-254, TLN-372 or TLN-499, as applicable, or other product candidates, which could result in the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities. Adverse events and SAEs that emerge during clinical investigation of or treatment with TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates may be deemed to be related to Treeline’s product candidates. Moreover, if Treeline’s product candidates are associated with undesirable side effects in clinical trials or have characteristics that are unexpected, Treeline may elect to abandon or limit its development to more narrow uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective, which may limit the commercial expectations for Treeline’s product candidates, if approved. This may require longer and more extensive clinical development, or regulatory authorities may increase the amount of data and information required to approve, market or maintain approval for TLN-121, TLN-254, TLN-372 and TLN-499 or future product candidates and could result in warnings and precautions in Treeline’s product labeling or a restrictive REMS. This may also result in an inability to obtain approval of TLN-121, TLN-254, TLN-372 and TLN-499 or future product candidates. Treeline, the FDA or other comparable foreign regulatory authorities or an IRB or ethics committee may suspend clinical trials of a product candidate at any time for various reasons, including a belief that participants in such trials are being exposed to unacceptable health risks or adverse side effects. Even if the side effects do not preclude a product candidate from obtaining or maintaining regulatory approval, undesirable side effects may inhibit market acceptance of such approved product due to its safety or tolerability versus other therapies. Further, it is possible that, as Treeline tests its product candidates in larger, longer and more extensive clinical trials, including with different dosing regimens, or as the use of its drug candidates becomes more widespread following any regulatory approval, illnesses, injuries, discomforts

and other adverse events that were observed in earlier trials, as well as conditions that did not occur or went undetected in previous trials, will be reported by patients. Any of these developments could materially harm Treeline’s business, financial condition, results of operations and prospects.

From time to time, Treeline may publicly disclose preliminary, topline or interim data from its clinical trials, such as preliminary, topline or interim data analysis from its ongoing Phase 1 clinical trials for TLN-121, TLN-254 and TLN-372. These data and related findings and conclusions may only reflect certain endpoints rather than all endpoints and are subject to change. Treeline also makes assumptions, estimations, calculations and conclusions as part of its analyses of data, and it may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the preliminary or topline results that Treeline reports may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated.

Preliminary or topline data also remain subject to review and verification procedures that may result in the final data being materially different from the preliminary or topline data Treeline previously published. As a result, preliminary and topline data should be viewed with caution until the final data are available. In addition, Treeline may report preliminary data or interim analyses of the clinical trials it may conduct and complete, which are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Adverse changes between preliminary or interim data and final data could significantly harm Treeline’s business and prospects.

Further, the information Treeline chooses to publicly disclose regarding a particular study or clinical trial is typically selected from a more extensive amount of available information. You or others may not agree with what Treeline determines is the material or otherwise appropriate information to include in its disclosure, and any information Treeline determines not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, activities or otherwise regarding a particular product, product candidate or its business. If the preliminary, topline or interim data that Treeline reports differ from later, final or actual results, or if others, including regulatory authorities, disagree with the conclusions reached, its ability to obtain approval for, and commercialize, its product candidates may be harmed, which could harm its business, financial condition, results of operations and prospects.

Treeline may seek to develop or commercialize its product candidates in combination with one or more currently approved therapies or therapies in development. The availability, pricing, supply, regulatory status and clinical performance of any such combination agent are outside Treeline’s control. If Treeline’s product candidates are used in combination with therapies that are supplied by third parties, Treeline will depend on those third parties to supply, in sufficient quantities and on a timely basis, the combination therapies on terms acceptable to Treeline, if at all. If Treeline is unable to obtain a sufficient supply of those combination therapies on commercially reasonable terms, or at all, Treeline’s clinical development or commercialization activities involving such combination therapies could be delayed, limited or prevented. Additionally, if a combination agent is withdrawn from the market, becomes the subject of a safety signal, is not supplied on commercially reasonable terms, or fails to demonstrate efficacy in the relevant indication, the development or commercialization of Treeline’s product candidate in combination with that agent could be delayed or abandoned, and any approval Treeline obtains may be limited to use in combination with a specific agent.

Even if any product candidate Treeline develops were to receive marketing approval or be commercialized for use in combination with other existing therapies, Treeline would continue to be subject to the risks that the FDA or comparable foreign regulatory authorities could revoke approval of the combination therapy, or that a third-party therapy that Treeline’s product candidates are used in combination with could be withdrawn from the market, or that safety, efficacy, manufacturing or supply issues could arise with respect to any of the combination therapies. This could result in Treeline’s products, if approved, being removed from the market or being less successful commercially. Treeline may also evaluate its product candidates in combination with one or more other therapies

that have not yet been approved for marketing by the FDA or comparable foreign regulatory authorities. Treeline will not be able to market and sell any product candidate in combination with any such unapproved therapies that do not ultimately obtain marketing approval. In addition, unapproved therapies face the same regulatory, development and commercial risks as Treeline’s own product candidates.

Treeline may expend its limited resources to pursue a particular product candidate in specific indications and fail to capitalize on product candidates or indications that may be more profitable or for which there is a greater likelihood of success. Because Treeline has limited financial and managerial resources, it focuses its development efforts on certain selected product candidates in certain selected indications. As a result, Treeline may forgo or delay pursuit of opportunities with other potential or future product candidates, or other indications for its current or any future product candidates that later prove to have greater commercial potential. Treeline’s resource allocation decisions may cause it to fail to capitalize on viable commercial products or profitable market opportunities. Treeline’s spending on current and future development programs and product candidates for specific indications may not yield any commercially viable product candidates. If Treeline does not accurately evaluate the commercial potential or target market for a particular product candidate, Treeline may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for it to retain sole development and commercialization rights to such product candidate.

Treeline’s pipeline is broad and diverse, comprising multiple product candidates and programs that span different modalities, biological targets, therapeutic areas and indications and that range across stages of development from discovery and preclinical research through Phase 1 clinical trials. Advancing a large number of programs in parallel requires substantial financial, managerial, scientific, clinical, regulatory, manufacturing and operational resources, as well as significant management attention, and Treeline has limited resources. As a result, Treeline must continually decide which product candidates, modalities and indications to prioritize, and it may be unable to advance all of its programs simultaneously or on its anticipated timelines. Treeline’s prioritization and resource-allocation decisions may prove to be incorrect, and constraints on its resources or management attention could delay one or more programs, cause Treeline to narrow, partner, deprioritize or discontinue programs that later prove to have greater scientific or commercial potential, or otherwise impair Treeline’s ability to execute across its pipeline. These challenges may be heightened as Treeline integrates its operations with Standard BioTools and operates as part of a combined public company, and any failure to manage the breadth and complexity of its pipeline effectively could materially and adversely affect Treeline’s business, financial condition, results of operations and prospects.

Treeline’s ability to identify, evaluate and advance new product candidates depends on its integrated drug discovery organization, which combines in-house wet-lab research — including custom assay development, structural and biophysical characterization of targets, and medicinal chemistry across small molecule inhibitors, protein degraders and targeted therapy antibody-drug conjugates (“TT-ADCs”) — with computational capabilities, including physics-based modeling and artificial intelligence and machine learning (“AI/ML”). Treeline uses these computational tools to accelerate and sharpen its experimental work and to prioritize experiments and compounds for synthesis and testing, rather than as a substitute for its wet-lab research or the judgment of its scientific personnel. The success of these efforts depends on the quality and completeness of the underlying biological and chemical data, the validity of Treeline’s models and assumptions, the integration of its experimental and computational work, and the expertise and continued service of its scientists. These methods are complex and rapidly evolving, and they may produce inaccurate predictions, may fail to identify viable product candidates, or may yield candidates that do not translate from preclinical models into clinical efficacy or an acceptable safety profile. Treeline’s discovery efforts may also be rendered less competitive by advances in computational chemistry, structural biology or AI/ML-based drug discovery achieved by others. Any of these outcomes could impair Treeline’s ability to replenish its pipeline and could materially harm Treeline’s business.

Treeline’s use of AI/ML and other computational methods is also subject to evolving legal, regulatory and ethical considerations, including with respect to data rights, the intellectual property protection of its computational methods and their outputs, and regulatory expectations regarding the evidence supporting computational claims. The legal and regulatory framework governing AI/ML continues to develop and remains uncertain, and compliance may be costly and time-consuming. Any failure by Treeline, or by the third parties on whose data, models or computing infrastructure it relies, to comply with these requirements, or any actual or perceived misuse of these tools, could expose Treeline to regulatory or legal liability or reputational harm, or could delay or limit its discovery and development activities.

Treeline’s product candidates span multiple modalities, including targeted protein degraders, such as TLN-121 and TLN-499, and small-molecule inhibitors, such as TLN-254 and TLN-372, and Treeline is pursuing additional modalities in its preclinical and discovery programs. Certain of these modalities, in particular targeted protein degradation and TT-ADCs, have limited clinical and regulatory precedent. The number of approved therapies based on these modalities remains limited, and the FDA and comparable foreign regulatory authorities have limited experience reviewing them. As a result, the regulatory pathway for Treeline’s product candidates may be longer, more uncertain, more complex or more costly than for therapies based on more established modalities, and regulators may apply novel or evolving standards or require additional preclinical or clinical data. These modalities may also present development and manufacturing challenges and may be associated with unexpected safety, efficacy, pharmacokinetic or immunogenicity findings that are not yet fully understood. Any of these factors could delay or prevent the development, regulatory approval or commercialization of Treeline’s product candidates, and adverse developments affecting one product candidate or program based on a given modality could negatively affect Treeline’s other potential or future product candidates or programs that rely on the same or similar approaches.

Treeline is conducting, and may in the future conduct, clinical trials of its product candidates outside the United States, and the FDA and comparable foreign regulatory authorities may not accept data from such trials. For example, Treeline’s ongoing Phase 1 study of TLN-372 is being conducted in the United States, Canada, Australia and Spain. The acceptance of data from clinical trials conducted outside the United States by the FDA or other comparable foreign regulatory authorities may be subject to certain conditions or may not be accepted at all. In cases where data from foreign clinical trials are intended to serve as the sole basis for regulatory approval in the United States, the FDA will generally not approve the application unless (i) the data are applicable to the U.S. population and U.S. medical practice; (ii) the trials were performed by clinical investigators of recognized competence and pursuant to GCP regulations; and (iii) the data may be considered valid without the need for an on-site inspection by the FDA or, if the FDA considers such an inspection to be necessary, the FDA is able to validate the data through an on-site inspection or other appropriate means. In addition, even where the foreign study data are not intended to serve as the sole basis for approval, the FDA will not accept the data from a foreign clinical study not conducted under an IND as support for an application for marketing approval unless the study is well-designed and well-conducted in accordance with GCPs and the FDA is able to validate the data from the study through an on-site inspection if deemed necessary. Additionally, the FDA’s clinical trial requirements, including sufficient size of patient populations and statistical powering, must be met. Many foreign regulatory authorities have similar approval requirements. In addition, such foreign trials are subject to the applicable local laws of the foreign jurisdictions where the trials are conducted. Conducting clinical trials outside the United States also exposes Treeline to additional risks, including risks associated with foreign exchange fluctuations, compliance with foreign manufacturing, customs, shipment and storage requirements, and cultural differences in medical practice and clinical research, and diminished protection of intellectual property in some countries.

There can be no assurance that the FDA or any comparable foreign regulatory authority will accept data from trials conducted outside of the United States or the applicable jurisdiction. For example, for FDA acceptance, Treeline will have to demonstrate that the foreign data are applicable to the U.S. population and U.S. medical practice. If the FDA or other comparable foreign regulatory authorities do not accept such data, it would result in the need for additional trials, which could be costly and time-consuming, and which may result in current or future product candidates that Treeline may develop being delayed or not receiving approval for commercialization in the applicable jurisdiction.

Treeline does not have a sales or marketing infrastructure and has no experience in the sales, marketing or distribution of any current or future product candidates. To achieve commercial success for any approved product, Treeline must either develop a sales and marketing organization or outsource these functions to third parties. In the future and if any of Treeline’s product candidates are approved, it may choose to build a focused sales, marketing and commercial support infrastructure to sell, or participate in sales activities with collaborators for some of Treeline’s current or future product candidates.

There are risks involved with both establishing Treeline’s own commercial capabilities and entering into arrangements with third parties to perform these services. For example, factors that may inhibit Treeline’s efforts to commercialize any approved product candidates include:

If the commercial launch of a product candidate, if approved, for which Treeline recruits a sales force and establishes marketing and other commercialization capabilities is delayed or does not occur for any reason, Treeline would have prematurely or unnecessarily incurred these commercialization expenses. This may be costly, and Treeline’s investment would be lost if Treeline cannot retain or reposition its commercialization personnel.

If Treeline were to enter into arrangements with third parties to perform sales, marketing, commercial support and distribution services, Treeline’s sales revenue or the profitability of sales revenue may be lower than if Treeline were to do so itself. In addition, Treeline may not be successful in entering into arrangements with third parties to commercialize its product candidates or may be unable to do so on terms that are favorable to it. Treeline may have little control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market Treeline’s product candidates effectively. If Treeline does not establish commercialization capabilities successfully, either on its own or in collaboration with third parties, it will not be successful in commercializing its product candidates, if approved.

Even if Treeline’s current or future product candidates receive regulatory approval, they may not gain adequate market acceptance among physicians, patients or their families, third-party payors and others in the medical community. The degree of market acceptance of any of Treeline’s approved product candidates will be dependent on a number of factors, including:

If any of Treeline’s current or future product candidates are approved but do not achieve an adequate level of acceptance by physicians, hospitals, healthcare payors and patients, it may not generate or derive sufficient revenue from that product candidate and its financial results could be negatively impacted. Treeline’s efforts to educate the medical community and third-party payors regarding the benefits of its products may require significant resources and may never be successful.

Treeline has estimated, and may in the future estimate, the timing of the accomplishment of various scientific, clinical, manufacturing, regulatory and other product development objectives. These milestones have and may include Treeline’s expectations regarding the commencement or completion of preclinical studies and clinical trials, data readouts, the submission of regulatory filings, the receipt of marketing approval or the realization of other commercialization objectives. The achievement of many of these milestones may be outside of Treeline’s control. All of these milestones are based on a variety of assumptions, including assumptions regarding capital resources, constraints and priorities, progress of and results from development activities and the receipt of key regulatory approvals or actions, any of which may cause the timing of achievement of the milestones to vary considerably from Treeline’s estimates. If Treeline or its collaborators fail to achieve announced milestones in the expected timeframes, the commercialization of the product candidates may be delayed, its credibility may be undermined and its business and results of operations may be harmed.

Prior to commercialization, Treeline’s product candidates must be approved by the FDA pursuant to an NDA in the United States and pursuant to similar marketing applications by comparable foreign regulatory authorities. The process of obtaining marketing approvals, both in the United States and abroad, is expensive and takes many years, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type, complexity and novelty of the product candidates involved. Failure to obtain marketing approval for a product candidate will prevent Treeline from commercializing the product candidate. Treeline has not received approval to market Treeline’s product candidates from regulatory authorities in any jurisdiction. Treeline has no experience in

submitting and supporting the applications necessary to gain marketing approvals, and, in the event regulatory authorities indicate that Treeline may submit such applications, Treeline may be unable to do so as quickly and efficiently as desired. Securing marketing approval requires the submission of extensive preclinical and clinical data and supporting information to regulatory authorities for each therapeutic indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the regulatory authorities. Treeline’s product candidates may not be effective, may be only moderately effective or may prove to have undesirable or unintended side effects, toxicities or other characteristics that may preclude Treeline’s obtaining marketing approval or prevent or limit commercial use. Regulatory authorities have substantial discretion in the approval process and may refuse to accept or file any application or may decide that Treeline’s data are insufficient for approval and require additional preclinical, clinical or other studies. In addition, varying interpretations of the data obtained from preclinical and clinical testing could delay, limit or prevent marketing approval of a product candidate.

Approval of Treeline’s product candidates may be delayed or refused for many reasons, including:

Even if Treeline’s product candidates meet their pre-specified safety and efficacy endpoints in clinical trials, the regulatory authorities may not complete their review processes in a timely manner and may not consider such clinical trial results sufficient to grant, or Treeline may not be able to obtain regulatory approval. Additional delays may result if an FDA Advisory Committee or other regulatory authority recommends non-approval or restrictions on approval. In addition, Treeline may experience delays or rejections based upon additional government regulation from future legislation or administrative action, or changes in regulatory authority policy during the period of product development, clinical trials and the review process.

Regulatory authorities also may approve a product candidate for more limited indications than requested or they may impose significant limitations in the form of narrow indications, warnings, contraindications or a REMS. These regulatory authorities may also grant approval subject to the performance of costly post-marketing clinical trials. In addition, regulatory authorities may not approve the labeling claims that are necessary or desirable for the successful commercialization of Treeline’s product candidates. Any of the foregoing scenarios could materially harm the commercial prospects for Treeline’s product candidates and adversely affect Treeline’s business, financial condition, results of operations and prospects.

Treeline’s approach includes the use of targeted protein degraders and other modalities with limited clinical and regulatory precedent. Adverse events in clinical trials of Treeline’s product candidates, or post-marketing activities, or in clinical trials of others developing similar products or that are related to approved therapies with similar modalities to Treeline’s product candidates, and the resulting publicity, as well as any other adverse events that may occur in the future in any of the therapeutic fields or modalities being pursued by Treeline, could result in a decrease

in demand for any product that Treeline may develop. If public perception is influenced by claims that the use of therapies in any of the therapeutic fields or modalities being pursued by Treeline is unsafe, whether related to Treeline’s therapies or those of its competitors, Treeline’s product candidates or products, if approved, may not be accepted by the general public or the medical community.

Future adverse events in any of the therapeutic fields or modalities being pursued by Treeline or the biopharmaceutical and biotechnology industries could also result in greater government regulation, stricter labeling requirements and potential regulatory delays in the testing or approvals of Treeline’s products. Any increased scrutiny could delay or increase the costs of obtaining marketing approval for Treeline’s current or future product candidates.

In some cases, a predictive biomarker may be used to identify the right patients for Treeline’s programs and its current or future product candidates. Accordingly, Treeline believes that its success may depend, in part, on its ability to use existing diagnostic tests from third parties or develop novel complementary diagnostics and/or novel companion diagnostics in collaboration with partners.

In the event that novel tests will need to be developed, Treeline has little experience in the development of diagnostics. Treeline expects to rely on partners in developing appropriate diagnostics to pair with its current or future product candidates. Treeline may be unsuccessful in entering into or maintaining collaborations for the development of companion diagnostics for use with its current or future product candidates in its markets of interest.

Complementary diagnostics and companion diagnostics are subject to regulation by the FDA and comparable foreign regulatory authorities as medical devices and require separate regulatory approval, clearance or certification prior to commercialization. In addition, if the FDA determines that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, the FDA generally will not approve the therapeutic product or new therapeutic product indication if the companion diagnostic is not also approved or cleared for that indication. Companion diagnostics are developed in conjunction with clinical programs for the associated therapeutic product, and the FDA has generally required premarket approval of companion diagnostics for certain therapies. The approval or clearance of a companion diagnostic as part of the therapeutic product’s further labeling limits the use of the therapeutic product to only those patients who express the specific characteristic, such as a biomarker, that the companion diagnostic was developed to detect.

If Treeline, its partners, or any third parties that Treeline engages to assist it, are unable to successfully develop complementary diagnostics and/or companion diagnostics for its product candidates and any future product candidates, or Treeline experiences delays in doing so:

Even if Treeline or its current or future partners are successful in the development of diagnostics for use with its current or future product candidates, there are also risks associated with the commercial supply of these diagnostics.

Treeline’s future growth may be dependent, in part, on its ability to develop and commercialize TLN-121, TLN-254, TLN-372 and TLN-499, if approved, and other potential or future product candidates in foreign markets

for which it may rely on collaboration with third parties. Treeline is not permitted to market or promote TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates before it receives regulatory approval from the applicable regulatory authority in that foreign market and may never receive such regulatory approval for TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates. To obtain separate regulatory approval in many other countries, Treeline must comply with numerous and varying regulatory requirements of such countries regarding safety and efficacy and governing, among other things, manufacturing, clinical trials and commercial sales, pricing and distribution of TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates, and it cannot predict success in these jurisdictions. If Treeline fails to comply with the regulatory requirements in international markets and receive applicable regulatory approvals, its target market will be reduced and its ability to realize the full market potential of TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates will be harmed and its business will be adversely affected. Treeline may not obtain foreign regulatory approvals on a timely basis, if at all. Its failure to obtain approval of any of TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates by regulatory authorities in another country may significantly diminish the commercial prospects of that product candidate and its business, financial condition, results of operations and prospects could be materially and adversely affected. Moreover, even if Treeline obtains approval of TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates and ultimately commercializes TLN-121, TLN-254, TLN-372 and TLN-499 or other product candidates in foreign markets, it would be subject to the risks and uncertainties, including the burden of complying with complex and changing foreign regulatory, tax, accounting and legal requirements and reduced protection of intellectual property rights in some foreign countries.

Treeline does not own or operate facilities for the manufacture of its product candidates and instead relies, and expects to continue to rely, on third-party manufacturers and supply partners to manufacture its current and future product candidates and the components thereof. Treeline intends to establish manufacturing relationships with a limited number of suppliers to manufacture raw materials, the drug substance and finished product of any product candidate for which Treeline is responsible for preclinical or clinical development. As part of any marketing approval, a manufacturer and its processes are required to be qualified by the FDA (or comparable regulatory authorities outside of the United States) prior to regulatory approval. If supply from an approved vendor is interrupted, there could be a significant disruption in commercial supply. An alternative vendor would need to be qualified through appropriate regulatory filings which could result in further delay. The FDA or other regulatory agencies outside of the United States may also require additional studies if a new supplier is relied upon for commercial production. Switching vendors may involve substantial costs and is likely to result in a delay in Treeline’s desired clinical and commercial timelines.

The process of manufacturing drugs is complex, highly regulated and subject to multiple risks. Manufacturing drugs is highly susceptible to product loss due to contamination, equipment failure, improper installation or operation of equipment, vendor or operator error, inconsistency in yields, variability in product characteristics and difficulties in scaling the production process. Even minor deviations from normal manufacturing processes could result in reduced production yields, product defects and other supply disruptions. If microbial, viral or other contaminations are discovered at the facilities of Treeline’s manufacturers, such facilities may need to be closed for an extended period of time to investigate and remedy the contamination, which could delay clinical trials and adversely harm Treeline’s business. Moreover, if the FDA determines that Treeline’s CDMOs are not in compliance with applicable laws and FDA regulations, including those governing cGMPs, the FDA may deny NDA approval until the deficiencies are corrected or Treeline replaces the manufacturer in Treeline’s NDA with a manufacturer that is in compliance. In addition, approved products and the facilities at which they are manufactured are required to maintain ongoing compliance with extensive FDA requirements and the requirements of other similar agencies, including ensuring that quality control and manufacturing procedures conform to cGMP requirements. As such, Treeline’s CDMOs are subject to continual review and periodic inspections to assess compliance with cGMPs. Furthermore, although Treeline does not have day-to-day control over the operations of its CDMOs, it is responsible for ensuring compliance with applicable laws and regulations, including cGMPs.

In addition, Treeline relies on third parties located in China for some of its contract manufacturing, and Treeline expects to continue to use such third-party manufacturers for such purposes. For any activities conducted in China,

Treeline is exposed to the possibility of product supply disruption and increased costs in the event of changes in the policies of the United States or Chinese governments, political unrest or unstable economic conditions in China. In addition, certain Chinese biotechnology companies may become subject to trade restrictions, sanctions, other regulatory requirements, or proposed legislation by the U.S. government, which could restrict or even prohibit Treeline’s ability to work with such entities, thereby potentially disrupting the supply of material to Treeline. For example, the BIOSECURE Act, which was signed into law in December 2025 as part of the National Defense Authorization Act for Fiscal Year 2026, prohibits U.S. federal agencies from entering into or renewing any contract, loan, or grant with any entity that uses biotechnology equipment or services produced or provided by a “biotechnology company of concern” to perform that contract. The BIOSECURE Act also prohibits U.S. government loan and grant recipients from using federal loan or grant money to enter into contracts with entities that use equipment from “biotechnology companies of concern” in the performance of any federal prime contract or subcontract. The Office of Management and Budget (“OMB”) of the U.S. Government will issue a list of “biotechnology companies of concern,” which will include certain companies that are identified on the U.S. Department of Defense’s (“US DoD”) annual List of Chinese Military Companies, also known as the 1260H List, other entities which the U.S. Government has deemed as such pursuant to a separate designation process, and certain subsidiary, parent, and successor entities of the foregoing. Treeline is currently party to agreements with WuXi Apptec Co., Ltd. (“WuXi Apptec”) and WuXi Biologics for certain development and manufacturing services. WuXi Apptec was designated on the 1260H List on June 8, 2026. On August 7, 2026, in response to WuXi Apptec’s challenge of the designation, the U.S. District Court for the District of Columbia granted a preliminary injunction barring the US DoD from enforcing its designation of WuXi AppTec as a “Chinese military company” on the 1260H List. The preliminary injunction will apply during the pendency of WuXi Apptec’s challenge of the designation, although the court expressly noted that the injunction does not prevent the US DoD from redesignating WuXi Apptec “on a justification that accurately describes the evidence and reasonably explains why that evidence satisfies the statute.” In addition, as indicated above, the OMB under the BIOSECURE Act may still designate “biotechnology companies of concern” pursuant to a separate designation process beyond inclusion on the 1260H List. Although WuXi Biologics is not currently designated on the 1260H List, WuXi Biologics was previously explicitly named in earlier drafts of the BIOSECURE Act and could be named by the OMB as one of the “biotechnology companies of concern.” Treeline may be restricted in its ability to work with such named companies to the extent Treeline would contract with, or otherwise receive funding from, the U.S. government. As a result, Treeline may need to seek alternative CDMO relationships. While Treeline believes it will be able to identify and contract with such alternative CDMOs, Treeline cannot guarantee that alternative CDMOs with the necessary capabilities and capacity would be available on a timeline that would not materially delay the development of its product candidates and cannot predict the terms of any such alternative arrangement nor what actions may ultimately be taken with respect to trade relations between the United States and China or other countries, what products and services may be subject to such actions or what actions may be taken by China or the other countries in retaliation. In addition, any unfavorable government policies on international trade, such as export controls, capital controls or tariffs, new legislation or regulations, renegotiation of existing trade agreements, or any retaliatory trade actions due to recent or future trade tension, may impede, delay, limit, or increase the cost of manufacturing Treeline’s product candidates. Such events could result in Treeline’s clinical or commercial supply of drug, packaging and other services being interrupted or limited, which would have an adverse effect on Treeline’s business, financial condition, results of operations and prospects.

In addition, there are risks associated with large scale manufacturing for clinical trials or commercial scale including, among others, cost overruns, potential problems with process scale-up, process reproducibility, stability issues, compliance with cGMPs, lot consistency and timely availability of raw materials. Even if Treeline obtains regulatory approval for any of Treeline’s product candidates, there is no assurance that manufacturers will be able to manufacture the approved product to specifications acceptable to the FDA or other regulatory authorities, to produce it in sufficient quantities to meet the requirements for the potential launch of the product or to meet potential future demand. If Treeline’s manufacturers are unable to produce sufficient quantities for clinical trials or for commercialization, commercialization efforts would be impaired, which would have an adverse effect on Treeline’s business, financial condition, results of operations and prospects.

Treeline believes that it will rely on a limited number of manufacturers for its product candidates for which it has identified single-source suppliers for the various steps of manufacture. This reliance on a limited number of manufacturers and the complexity of drug manufacturing and the difficulty of scaling up a manufacturing process could cause the delay of clinical trials, regulatory submissions, required approvals or commercialization of

Treeline’s product candidates, cause Treeline to incur higher costs and prevent Treeline from commercializing Treeline’s product candidates successfully. Furthermore, if Treeline’s suppliers fail to deliver the required clinical or commercial quantities of materials on a timely basis and at commercially reasonable prices, and Treeline is unable to secure one or more replacement suppliers capable of production in a timely manner at a substantially equivalent cost, Treeline’s clinical trials may be delayed or Treeline could lose potential revenue.

In the future, Treeline may decide to collaborate with other pharmaceutical and biotechnology companies for the development and potential commercialization of existing and future product candidates. It faces significant competition in seeking appropriate collaborators. Whether Treeline reaches a definitive agreement for a collaboration will depend, among other things, upon its assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Those factors may include the design or results of clinical trials, the likelihood of approval by the FDA or comparable foreign regulatory authorities, the potential market for the subject product candidate, the costs and complexities of manufacturing and delivering such product candidate to patients, the potential of competing drugs, the existence of uncertainty with respect to its ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge and industry and market conditions generally. Collaborations are complex and time-consuming to negotiate and document. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that may result in a reduced number of potential future collaborators.

Treeline may not be able to negotiate collaborations on a timely basis, on acceptable terms, or at all. If Treeline is unable to do so, it may have to curtail the development of the product candidate for which it is seeking to collaborate, reduce or delay its development program or one or more of its other development programs, delay its potential commercialization or reduce the scope of any sales or marketing activities, or increase its expenditures and undertake development or commercialization activities at its own expense. If Treeline elects to increase its expenditures to fund development or commercialization activities on its own, it may need to obtain additional capital, which may not be available to Treeline on acceptable terms or at all. If it does not have sufficient funds, it may not be able to further develop its product candidates or bring them to market and generate product revenue.

The success of any potential collaboration arrangements will depend heavily on the efforts and activities of its collaborators. Collaborators generally have significant discretion in determining the efforts and resources that they will apply to these collaborations. Disagreements between parties to a collaboration arrangement regarding clinical development and commercialization matters can lead to delays in the development process or commercializing the applicable product candidate and, in some cases, termination of such collaboration arrangements. These disagreements can be difficult to resolve if neither of the parties has final decision-making authority. Collaborations with pharmaceutical or biotechnology companies and other third parties often are terminated or allowed to expire by the other party. Any such termination or expiration would adversely affect Treeline financially and could harm its business reputation.

Treeline’s current and any future product candidates are subject to extensive governmental regulations relating to, among other things, research, testing, development, manufacturing, approval, recordkeeping, reporting, labeling, storage, packaging, advertising and promotion, pricing, post-approval monitoring, marketing and distribution of products. Rigorous preclinical testing and clinical trials and an extensive regulatory approval process are required to be completed successfully in the United States and in many foreign jurisdictions before a new biopharmaceutical product can be marketed. Satisfaction of these and other regulatory requirements is costly, time-consuming, uncertain and subject to unanticipated delays. It is possible that none of the product candidates Treeline may develop will obtain the regulatory approvals necessary for it to begin marketing and selling them.

While Treeline has clinical trials currently ongoing, it has limited experience as a company in conducting and managing clinical trials and has no experience completing the later-stage clinical trials necessary to obtain

regulatory approvals, including approval by the FDA, or obtaining marketing approval for any product candidate. The time required to obtain FDA and other approvals is unpredictable but typically takes many years following the commencement of clinical trials, depending on the type, complexity and novelty of the product candidate. The standards that the FDA and its foreign counterparts use when regulating Treeline require judgment and can change, which makes it difficult to predict with certainty their application. Any analysis Treeline performs of data from preclinical and clinical activities is subject to confirmation and interpretation by regulatory authorities, which could delay, limit or prevent regulatory approval. Treeline may also encounter unexpected delays or increased costs due to new government regulations, for example, from future legislation or administrative action, or from changes in FDA policy during the period of product development, clinical trials and FDA regulatory review. It is not possible to predict whether additional legislative changes will be enacted, or whether FDA or foreign regulations, guidance or interpretations will be changed, or the impact of such changes, if any. Any elongation or de-prioritization of preclinical studies or clinical trials or delay in regulatory review resulting from such disruptions could adversely affect the development and study of Treeline’s current or other future product candidates.

Further, the FDA and other comparable foreign regulatory authorities may respond to any IND or NDA (and their foreign equivalents) that Treeline may submit by defining requirements that Treeline does not anticipate. Such responses could delay clinical development of Treeline’s current or any future product candidates.

In addition, the approval policies or regulations of the FDA and other comparable regulatory authorities in other jurisdictions may change in a manner rendering Treeline’s clinical or manufacturing data insufficient for approval. Any delay or failure in obtaining required approvals could have a material and adverse effect on Treeline’s ability to generate revenues from the particular product candidate for which it is seeking approval. Furthermore, any regulatory approval to market a product may be subject to limitations on the approved uses for which Treeline may market the product or on the labeling or other restrictions.

Treeline is also subject to or may in the future become subject to numerous foreign regulatory requirements governing, among other things, the conduct of clinical trials, manufacturing and marketing authorization, pricing and third-party reimbursement. The foreign regulatory approval process varies among countries and may include all of the risks associated with the FDA approval process described above, as well as risks attributable to the satisfaction of local regulations in foreign jurisdictions. Moreover, the time required to obtain approval may differ from that required to obtain FDA approval. FDA approval does not ensure approval by regulatory authorities outside the United States and vice versa. Any delay or failure to obtain United States or foreign regulatory approval for a product candidate could have a material and adverse effect on Treeline’s business, financial condition, results of operations and prospects.

From time to time during the development and regulatory approval process for Treeline’s product candidates, Treeline engages in discussions with the FDA and other regulatory authorities regarding its development programs, including discussions about the regulatory requirements for approval. Sometimes different regulatory authorities provide different or conflicting advice. While Treeline will attempt to harmonize the advice it receives from multiple regulatory authorities, it is not always practical to do so. Also, Treeline may choose not to harmonize conflicting advice when harmonization would significantly delay clinical trial data or when it believes it is otherwise inappropriate. In addition, regulatory authorities may change their views on aspects of the clinical programs, including study designs, or the ability of the studies as designed to support approval of a product. If Treeline is unable to effectively and efficiently resolve and comply with the inquiries and requests of the FDA and other regulatory authorities, the approval of its product candidates may be delayed or denied, and their value may be reduced.

Where an expedited program is available in a particular country, Treeline may seek to utilize such program for some or all of Treeline’s product candidates. For example, various regulatory programs in the United States, such as Breakthrough Therapy Designation, Fast Track Designation or Priority Review Designation, are designed to expedite the development and review of therapies to treat certain diseases. Treeline may seek such designations, and comparable designations by foreign regulatory authorities, for one or more of its product candidates for the treatment of certain indications, as applicable. However, regulatory authorities have broad discretion as to whether or not to grant such designations.

Even if Treeline receives such a designation for any product candidates in the future, Treeline may not experience a faster development process, review or approval compared to drugs considered for approval under conventional regulatory procedures and such a designation does not assure ultimate approval by the applicable regulatory authority. Even if one or more of Treeline’s product candidates qualify for such a designation, the applicable regulatory authority may later decide that such product candidates no longer meet the conditions for qualification.

Obtaining and maintaining regulatory approval of Treeline’s product candidates in one jurisdiction does not guarantee that Treeline will be able to obtain or maintain regulatory approval in any other jurisdiction. For example, even if the FDA grants regulatory approval of a product candidate, comparable regulatory authorities in foreign jurisdictions must also approve the manufacturing, marketing and promotion of the product candidate in those countries. Moreover, the receipt of regulatory approval in another jurisdiction, such as the conditional approval of TLN-254 in China, does not expedite or result in approval in the United States or other jurisdictions. However, a failure or delay in obtaining regulatory approval in one jurisdiction may have a negative effect on the regulatory approval process in others. Approval procedures vary among jurisdictions and can involve requirements and administrative review periods different from those in the United States, including additional preclinical studies or clinical trials as clinical trials conducted in one jurisdiction may not be accepted by regulatory authorities in other jurisdictions. In many jurisdictions outside the United States, a product candidate must be approved for reimbursement before it can be approved for sale in that jurisdiction. In some cases, the price that Treeline intends to charge for Treeline’s products is also subject to approval. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for Treeline and could delay or prevent the introduction of Treeline’s products in certain countries. If Treeline or any partner Treeline works with fails to comply with the regulatory requirements in international markets or fails to receive applicable regulatory approvals, Treeline’s target market will be reduced and Treeline’s ability to realize the full market potential of Treeline’s product candidates will be harmed.

Any regulatory approvals that Treeline obtains for Treeline’s current or any future product candidates may also be subject to limitations on the approved indicated uses for which a product may be marketed or to the conditions of approval, or contain requirements for potentially costly post-marketing testing and surveillance to monitor the safety and efficacy of the product candidate. In addition, if the FDA or other comparable foreign regulatory authorities approve any of Treeline’s product candidates, the manufacturing processes, labeling, packaging, distribution, post-approval monitoring and adverse event reporting, storage, import, export, advertising, promotion and recordkeeping for the product will be subject to extensive and ongoing regulatory requirements. The FDA has significant post-market authority, including the authority to require labeling changes based on new safety information and to require post-market studies or clinical trials to evaluate safety risks related to the use of a product or to require withdrawal of the product from the market. The FDA also has the authority to require a REMS after approval, which may impose further requirements or restrictions on the distribution or use of an approved drug. The manufacturing facilities Treeline uses to make future product candidates, if any, will also be subject to periodic review and inspection by the FDA or other comparable foreign regulatory authorities, including for continued compliance with cGMP requirements. The discovery of any new or previously unknown problems with Treeline’s CDMOs, manufacturing processes or facilities may result in restrictions on the product, manufacturer or facility, including withdrawal of the product from the market. If Treeline relies on CDMOs, Treeline will not have control over compliance with applicable rules and regulations by such manufacturers.

Moreover, any product promotion and advertising will also be subject to regulatory requirements and continuing regulatory review. The FDA imposes stringent restrictions on manufacturers’ communications regarding use of their products. If Treeline promotes Treeline’s product candidates or any of Treeline’s future product

candidates in a manner inconsistent with FDA-approved labeling or otherwise not in compliance with FDA regulations, Treeline may be subject to enforcement action. Moreover, while Treeline believes that Treeline’s current product candidates or any future product candidates may provide better safety or effectiveness as compared to approved products, if Treeline does not study Treeline’s current product candidates or any future product candidates in head-to-head trials with those products, Treeline will not be able to make comparative claims for Treeline’s products, if approved.

If Treeline or Treeline’s CDMOs or other service providers fail to comply with applicable continuing regulatory requirements in the United States or foreign jurisdictions in which Treeline seeks to market Treeline’s products, Treeline or they may be subject to, among other things:

Any government investigation of alleged violations of law could require Treeline to expend significant time and resources in response and could generate adverse publicity. Any failure to comply with ongoing regulatory requirements may significantly and adversely affect Treeline’s ability to commercialize and generate revenue from Treeline’s products, if approved. If regulatory sanctions are applied or if regulatory approval is withdrawn, the value of Treeline and Treeline’s operating results will be adversely affected.

Subsequent discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with Treeline’s CDMOs or manufacturing processes, or failure to comply with regulatory requirements, may result in these same consequences.

If Treeline is slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if Treeline is not able to maintain regulatory compliance, Treeline may lose any regulatory approval that Treeline may have obtained and Treeline may not achieve or sustain profitability, which would adversely affect Treeline’s business. Treeline also cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or abroad.

In addition, three decisions from the U.S. Supreme Court in July 2024 may lead to an increase in litigation against regulatory agencies that could create uncertainty and thus negatively impact Treeline’s business. The first decision overturned established precedent that required courts to defer to regulatory agencies’ interpretations of ambiguous statutory language. The second decision overturned regulatory agencies’ ability to impose civil penalties in administrative proceedings. The third decision extended the statute of limitations within which entities may challenge agency actions. These cases may result in increased litigation by industry against regulatory agencies and impact how such agencies choose to pursue enforcement and compliance actions. However, the specific, lasting

effects of these decisions, which may vary within different judicial districts and circuits, are unknown. Treeline also cannot predict the extent to which regulations, policies, and decisions of the FDA or other regulatory authorities, such as the SEC, may become subject to increasing legal challenges, delays, and changes.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, government shutdowns, statutory, regulatory, and policy changes, the FDA’s ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the FDA’s ability to perform routine functions. In addition, government funding of other government agencies on which Treeline’s operations may rely, including those that fund research and development activities, is subject to the political process, which is inherently fluid and unpredictable.

Disruptions at the FDA and other government agencies or comparable foreign regulatory authorities may also slow the time necessary for the review and/or approval of clinical trial or marketing applications, which would adversely affect Treeline’s business. For example, the U.S. government has reduced the number of federal employees, including at FDA, by establishing voluntary termination programs, by position eliminations or by involuntary terminations, and the FDA has experienced turnover at senior levels. Changes in FDA staffing could result in delays in the FDA’s responsiveness or in its ability to review submissions or applications, issue regulations or guidance, or implement or enforce regulatory requirements in a timely fashion or at all.

Similar consequences would also result in the event of a significant shutdown of the federal government. For example, over the last several years, and most recently in late 2025, the U.S. government has shut down several times, and certain regulatory agencies, such as the FDA, had to furlough critical employees and stop critical activities. If a prolonged government shutdown occurs, or if geopolitical or global health concerns prevent the FDA from conducting their regular inspections, reviews, or other regulatory activities, or if the volume of applications to the FDA for new product candidates increases materially, it could significantly impact the ability of the FDA to timely review and process Treeline’s regulatory submissions, which could have a material adverse effect on Treeline’s business. Further, future government shutdowns or delays could impact Treeline’s ability to access the public markets and obtain necessary capital in order to properly capitalize and continue Treeline’s operations. If any legislation, executive orders, or lapses in agency funding impose constraints on the FDA’s ability to engage in oversight and implementation activities in the normal course, Treeline’s business may be negatively impacted.

FDA-regulated industries, such as Treeline’s, face uncertainty with regard to the regulatory environment Treeline will face as Treeline proceeds with research and development, and possibly in the future, commercialization. Some of these efforts have manifested to date in the form of personnel measures that could impact the FDA’s ability to hire and retain key personnel, which could result in delays or limitations on Treeline’s ability to obtain guidance from the FDA on Treeline’s product candidates in development and obtain the requisite regulatory approvals in the future. Moreover, the U.S. government paused payments by, reduced the budget of, and terminated grants provided by the National Institutes of Health (“NIH”) related to its funding for medical research, which has decreased, and may continue to decrease, the ability of facilities that rely on NIH funding to enroll and conduct clinical trials or increase the costs to Treeline of conducting clinical trials. Some of these actions have been challenged in court and there remains general uncertainty regarding future activities. New executive orders, regulations, policies or guidance could be issued or promulgated that adversely affect Treeline or create a more challenging or costly environment to pursue the development of new therapeutic products. Alternatively, state governments may attempt to address or react to changes at the federal level with changes to their own regulatory frameworks in a manner that is adverse to Treeline’s operations. If Treeline becomes negatively impacted by future governmental orders, regulations, policies or guidance, there could be a material adverse effect on Treeline and Treeline’s business.

Treeline’s current and future arrangements with healthcare providers, healthcare organizations, third-party payors and customers expose Treeline to broadly applicable anti-bribery, fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which Treeline researches, markets, sells and distributes any of Treeline’s product candidates, if approved. Restrictions under applicable federal and state anti-bribery and healthcare laws and regulations, include the following:

Efforts to ensure that Treeline’s current and future business arrangements with third parties comply with applicable healthcare laws and regulations could involve substantial costs. It is possible that governmental authorities will conclude that Treeline’s business practices do not comply with current or future statutes, regulations, agency guidance or case law involving applicable fraud and abuse or other healthcare laws and regulations. If Treeline’s operations are found to be in violation of any such requirements, Treeline may be subject to significant penalties, including civil, criminal and administrative penalties, damages, fines, disgorgement, imprisonment, the curtailment or restructuring of Treeline’s operations, loss of eligibility to obtain approvals from the FDA, exclusion from participation in government contracting, healthcare reimbursement or other government programs, including Medicare and Medicaid, integrity oversight and reporting obligations, or reputational harm, any of which could adversely affect Treeline’s financial results. These risks cannot be entirely eliminated. Any action against Treeline for an alleged or suspected violation could cause Treeline to incur significant legal expenses and could divert Treeline’s management’s attention from the operation of Treeline’s business, even if Treeline’s defense is successful. In addition, achieving and sustaining compliance with applicable laws and regulations may be costly to Treeline in terms of money, time and resources.

In the United States and some foreign jurisdictions, there have been, and Treeline expects there will continue to be, a number of legislative and regulatory changes to the healthcare system, including cost containment measures that may reduce or limit coverage and reimbursement for newly approved drugs and affect Treeline’s ability to profitably sell any product candidates for which Treeline obtains marketing approval. In particular, there have been and continue to be a number of initiatives at the U.S. federal and state levels that seek to reduce healthcare costs and improve the quality of care.

For example, the Patient Protection and Affordable Care Act, as amended (the “ACA”), made significant changes to the healthcare system, including an increase to manufacturers’ rebate liability under the Medicaid Drug Rebate Program, the imposition of a significant annual fee on companies that manufacture or import branded prescription drug products, and other health policy reforms that substantially changed the way healthcare is financed by both governmental and private insurers. In addition, legislative changes adopted since the ACA include aggregate reductions to Medicare payments to providers of 2% per fiscal year, which began in 2013 and, as a result of subsequent legislation, will remain in effect through 2032 unless additional Congressional action is taken.

Since that time, there has continued to be heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several presidential executive orders, Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, reduce the costs of drugs under Medicare, and reform government program reimbursement methodologies for drug products. Several of these initiatives culminated in the enactment of the Inflation Reduction Act (“IRA”) in August 2022, which, among other things, requires the U.S. Department of Health and Human Services (“HHS”) to directly negotiate the selling price of a statutorily specified number of drugs and biologics each year that CMS reimburses under Medicare Part B and Part D. The negotiated price may not

exceed a statutory ceiling price. Only high-expenditure single-source drugs that have been approved for at least seven years (11 years for single-source biologics) are eligible to be selected by CMS for negotiation, with the negotiated price taking effect two years after the selection year. For 2026, the first year in which negotiated prices become effective, CMS selected 10 high-cost Medicare Part D products in 2023, negotiations began in 2024, and the negotiated maximum fair price for each product has been announced. In addition, CMS selected and announced the negotiated maximum fair price for 15 additional Medicare Part D drugs, which will become effective in 2027. For 2028, CMS has selected an additional 15 drugs, comprised of drugs covered under Medicare Part D and, for the first time, drugs payable under Medicare Part B. For 2029 and subsequent years, 20 Part B or Part D drugs will be selected. Due to a statutory amendment in July 2025, a drug or biological product that has one or more orphan drug designations will be excluded from the IRA’s price negotiation requirements, but will lose that exclusion if it is approved for an indication that is not one of the designated rare diseases or conditions, unless such disqualifying approvals are withdrawn by the time CMS evaluates the drug for selection for negotiation. The law also imposes rebates on Medicare Part B and Part D drugs whose prices have increased at a rate greater than the rate of inflation, and in November 2024, CMS finalized regulations for these inflation rebates. In addition, the law eliminated the “donut hole” under Medicare Part D beginning in 2025 by significantly lowering the beneficiary maximum out-of-pocket cost and requiring manufacturers to subsidize, through a newly established manufacturer discount program, 10% of Part D enrollees’ prescription costs for brand drugs below the out-of-pocket limit, and 20% once the out-of-pocket limit has been reached. The IRA permits the Secretary of HHS to implement many of these provisions through guidance, as opposed to regulation, for the initial years. Manufacturers that fail to comply with the IRA may be subject to various penalties, including civil monetary penalties. The provisions related to the negotiation of selling prices of high-expenditure single-source drugs and biologics have been challenged in numerous lawsuits, but to date those challenges have been unsuccessful, and in May 2026 the U.S. Supreme Court declined to review the first wave of manufacturer challenges, leaving in place lower court decisions that upheld the program. Additional challenges to later negotiation cycles remain pending and further challenges may be brought, but CMS is continuing to implement the program, which is expected to have a significant impact on the biopharmaceutical industry.

Further, in July 2025, the One Big Beautiful Bill Act (the “OBBBA”) was enacted, which, among other things, narrowed access to ACA marketplace enrollment, and is anticipated to reduce Medicaid spending and enrollment through measures such as work requirements and other eligibility conditions for certain beneficiaries, caps on state-directed payments in Medicaid managed care, and limits on states’ ability to use provider taxes to finance their Medicaid programs. The current federal administration is pursuing policies to reduce regulations and expenditures across government including at HHS, which include the FDA and CMS, and related agencies. These actions included, for example, directives to reduce agency workforce, rescind a Biden administration executive order tasking the Center for Medicare and Medicaid Innovation to consider new payment and healthcare models to limit drug spending, and promote most-favored-nation (“MFN”) drug pricing, among other directives. For example, on May 12, 2025, President Trump issued an Executive Order that, among other things, required HHS, within 30 days, to establish and communicate to drug manufacturers MFN price targets designed to bring drug prices for American patients in line with those in comparably developed nations. If significant progress towards MFN pricing is not achieved, the Executive Order requires HHS to propose a rulemaking to implement MFN pricing. On December 19, 2025, CMS released two proposed rules that would incorporate MFN pricing principles into federal reimbursement for prescription drugs. The first proposal, the Global Benchmark for Efficient Drug Pricing Model (“GLOBE”) for Medicare Part B, would require manufacturers of specified single source drugs and sole source biologics to pay incremental rebates based on international benchmark prices, with participation triggered for products meeting CMS’s spending and eligibility criteria. The second proposal, the Guarding U.S. Medicare Against Rising Drug Costs (“GUARD”) model for Medicare Part D, would similarly mandate manufacturer rebates for qualifying sole source drugs where the Medicare net price exceeds an MFN benchmark derived from international reference pricing methodologies. As proposed, GLOBE would begin a five-year performance period on October 1, 2026 and GUARD would begin its performance period in 2027. These proposals will likely be subject to legal challenges that could delay their implementation or modify their impact on manufacturer pricing and revenue. Additionally, in November 2025, CMS introduced the GENErating cost Reductions for U.S. Medicaid (“GENEROUS”) Model, a voluntary MFN framework for manufacturers participating in the Medicaid Drug Rebate Program. Although it is voluntary, the GENEROUS model could also impact the drug pricing landscape for manufacturers.

If the proposed GLOBE and GUARD model rules or other MFN pricing rules are finalized, they are likely to mandate reduced prices of at least some drugs in the United States, if they are also sold in comparator countries.

Even if Treeline does not market drugs in such countries, Treeline will be indirectly affected if Treeline’s drugs compete with drugs that were reduced by MFN pricing. Further, as part of the Make America Healthy Again Commission’s recent Strategy Report, the administration is working across government agencies to increase enforcement on direct-to-consumer pharmaceutical advertising. These actions and policies may significantly reduce U.S. drug prices, potentially impacting manufacturers’ global pricing strategies and profitability, while increasing their operational costs and compliance risks.

At the state level, legislatures have increasingly passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access, restrictions or prohibitions on certain marketing practices, reporting of specified categories of remuneration provided to health care practitioners, marketing cost disclosure and transparency measures, including reporting and justification of launch prices or price increases above specified thresholds, and, in some cases, measures designed to encourage importation from other countries and bulk purchasing.

Treeline expects that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for pharmaceuticals and other healthcare products and services, lead to more rigorous coverage criteria, or result in reduced demand for Treeline’s product candidates or any future product candidates or additional pricing pressures. The implementation of cost containment measures or other healthcare reforms may prevent Treeline from being able to generate revenue, attain profitability, or commercialize Treeline’s products, if approved.

The availability of coverage and the adequacy of reimbursement by governmental healthcare programs, such as Medicare and Medicaid, private health insurers and other third-party payors are essential for most patients to be able to afford prescription medications such as Treeline’s product candidates, if approved. Sales of any of Treeline’s product candidates that receive regulatory approval will be dependent substantially, both in the United States and internationally, on the extent to which the costs of Treeline’s product candidates will be paid by health maintenance, managed care, pharmacy benefit, and similar healthcare management organizations or reimbursed by government health administration authorities, private health coverage insurers and other third-party payors. If reimbursement is not available, or is available only to limited levels, Treeline may not be able to successfully commercialize Treeline’s product candidates. Even if coverage is provided, the approved reimbursement amount may not be high enough to allow Treeline to establish or maintain pricing sufficient to realize an adequate return on Treeline’s investment. Coverage and reimbursement may impact the demand for, or the price of, any product candidate for which Treeline obtains regulatory approval. If coverage and reimbursement are not available or reimbursement is available only to limited levels, Treeline may not successfully commercialize any product candidate for which Treeline obtains regulatory approval.

There is significant uncertainty related to insurance coverage and reimbursement of newly approved products. In the United States, principal decisions about reimbursement for new products are typically made by CMS. CMS decides whether and to what extent a new product will be covered and reimbursed under Medicare, and private payors often follow CMS’s decisions regarding coverage and reimbursement to a substantial degree. However, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for the product. As a result, the coverage determination process is often time-consuming and costly. This process will require Treeline to provide scientific and clinical support for the use of Treeline’s products to each payor separately, with no assurance that coverage and adequate reimbursement will be applied consistently or obtained in the first instance. Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products. Further, such payors are increasingly challenging the price, examining the medical necessity and reviewing the cost effectiveness of medical products. There may be especially significant delays in obtaining coverage and reimbursement for newly approved products. Third-party payors may limit coverage to specific products on an approved list, known as a formulary, which might not include all FDA-approved products for a particular indication. Treeline may need to conduct expensive pharmaco-economic studies to demonstrate the medical necessity and cost effectiveness of

Treeline’s products. Nonetheless, Treeline’s product candidates may not be considered medically necessary or cost effective. Treeline cannot be sure that coverage and reimbursement will be available for any product that Treeline commercializes and, if reimbursement is available, what the level of reimbursement will be.

Moreover, increasing efforts by governmental and third-party payors in the United States and abroad to cap or reduce healthcare costs may cause such organizations to limit both coverage and the level of reimbursement for newly approved products and, as a result, they may not cover or provide adequate payment for Treeline’s product candidates, if approved. Treeline expects to experience pricing pressures in connection with the sale of Treeline’s product candidates due to the trend toward managed healthcare, the increasing influence of health maintenance organizations and additional legislative changes. The downward pressure on healthcare costs in general, particularly prescription drugs and surgical procedures and other treatments, has become very intense. As a result, increasingly high barriers are being erected to the entry of new products.

U.S. and foreign anti-corruption, anti-money laundering, export control, sanctions and other trade laws and regulations prohibit, among other things, companies and their employees, agents, CROs, CDMOs, legal counsel, accountants, consultants, contractors and other partners from authorizing, promising, offering, providing, soliciting, or receiving directly or indirectly, corrupt or improper payments or anything else of value to or from recipients in the public or private sector. Violations of these laws can result in substantial criminal fines and civil penalties, imprisonment, the loss of trade privileges, debarment, tax reassessments, breach of contract and fraud litigation, reputational harm and other consequences. Treeline has direct or indirect interactions with officials and employees of government agencies or government-affiliated hospitals, universities and other organizations. Treeline also expects Treeline’s non-U.S. activities to increase over time. Treeline expects to rely on third parties for research, preclinical studies and clinical trials and/or to obtain necessary permits, licenses, patent registrations and other regulatory approvals. Treeline can be held liable for the corrupt or other illegal activities of Treeline’s personnel, agents, or partners, even if Treeline does not explicitly authorize or have prior knowledge of such activities.

Treeline is also subject to export control and import laws and regulations, including the U.S. Export Administration Regulations, U.S. Customs regulations and various economic and trade sanctions regulations administered by the U.S. Treasury Department’s Office of Foreign Assets Control. Compliance with applicable regulatory requirements regarding the export of Treeline’s products may create delays in the introduction of Treeline’s products in international markets or, in some cases, prevent the export of Treeline’s products to some countries altogether. Furthermore, U.S. export control laws and economic sanctions prohibit the provision of certain products and services to countries, governments and persons targeted by U.S. sanctions.

Any violations of the laws and regulations described above may result in substantial civil and criminal fines and penalties, imprisonment, the loss of export or import privileges, debarment, tax reassessments, breach of contract and fraud litigation, reputational harm and other consequences.

In some countries, particularly member states of the EU, the pricing of therapeutic products is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after receipt of regulatory approval for a product. In addition, there can be considerable pressure by governments and other stakeholders on prices and reimbursement levels, including as part of cost containment measures. Political, economic and regulatory developments may further complicate pricing negotiations, and pricing negotiations may continue after reimbursement has been obtained. Reference pricing used by various EU member states and parallel distribution, or arbitrage between low-priced and high-priced member states, can further reduce prices. Reduced prices in EU member states could also result in reduced prices in the U.S. if the U.S. finalizes the proposed GLOBE or GUARD models or other MFN pricing rules (see “Risks Related to Government Regulation — Treeline may face difficulties from healthcare legislative and regulatory reform measures.”). In addition, to obtain coverage and reimbursement or pricing approvals in some countries, Treeline may be required to conduct a clinical trial or other studies that compare the cost-effectiveness of Treeline’s current or any future product candidates to

other available therapies in order to obtain or maintain reimbursement or pricing approval. Publication of discounts by third-party payors or authorities may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries. If reimbursement of any product candidate approved for marketing is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, Treeline’s business, financial condition, results of operations or prospects could be materially and adversely affected.

Treeline’s success is dependent in part on Treeline’s ability to obtain and maintain proprietary or intellectual property protection in the United States and other countries for Treeline’s current product candidates or any future product candidates, as well as Treeline’s core technologies, including Treeline’s manufacturing know-how. Treeline strives to protect and enhance the proprietary technology, inventions and improvements that are commercially important to the development of Treeline’s business by seeking, maintaining and defending Treeline’s intellectual property, whether developed internally or licensed from third parties. Treeline also relies on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop, strengthen and maintain Treeline’s proprietary position in the therapeutic fields being pursued by Treeline.

The patent position of biotechnology and biopharmaceutical companies generally is highly uncertain, involves complex legal and factual questions, and has in recent years been the subject of much litigation. The degree of patent protection Treeline requires to successfully compete in the marketplace may be unavailable or severely limited in some cases and may not adequately protect Treeline’s rights or permit Treeline to gain or keep any competitive advantage. Treeline cannot provide any assurances that any of Treeline’s owned or licensed patent applications will mature into issued patents, and cannot provide any assurances that any such patents, if issued, will include claims with a scope sufficient to protect Treeline’s current and future product candidates or otherwise provide any competitive advantage. Additionally, patents can be enforced only in those jurisdictions in which the patent has issued. Furthermore, patents have a limited lifespan. In the United States, the natural expiration of a patent is generally 20 years after its first nonprovisional U.S. filing. The natural expiration of a patent outside of the United States varies in accordance with provisions of applicable local law, but is generally 20 years from the earliest local filing date. Various extensions may be available; however, the life of a patent, and the protection it affords, is limited. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized.

Treeline’s licensed patent portfolio may not provide Treeline with adequate and continuing patent protection sufficient to exclude others from commercializing products similar to Treeline’s product candidates, including biosimilar and interchangeable versions of such products. In addition, the patent portfolio licensed to Treeline is, or may be, licensed to third parties outside Treeline’s licensed field, and such third parties may have certain enforcement rights. Thus, patents licensed to Treeline could be put at risk of being invalidated or interpreted narrowly in litigation filed by or against another licensee or in administrative proceedings brought by or against another licensee in response to such litigation or for other reasons.

Other parties have developed technologies that may be related or competitive to Treeline’s own and such parties may have filed or may file patent applications, or may have received or may receive patents, claiming inventions that may overlap or conflict with those claimed in Treeline’s own patent applications or issued patents. Publication of discoveries in the scientific literature lags behind the actual discoveries, and patent applications in the United States and in other jurisdictions are typically not published until 18 months after filing, or in some cases not at all. Therefore, Treeline cannot know with certainty whether the inventors of Treeline’s patents and applications were the first to make the inventions claimed in those patents or pending patent applications, or that they were the first to file for patent protection of such inventions. Further, Treeline cannot assure that all of the potentially relevant prior art relating to Treeline’s patents and patent applications has been found. If such prior art exists, it can invalidate a patent or prevent a patent from issuing from a pending patent application. As a result, the issuance, scope, validity

and commercial value of Treeline’s patent rights cannot be predicted with any certainty. Further, if the breadth or strength of protection provided by Treeline’s patents and patent applications is threatened, regardless of the outcome, it could dissuade companies from collaborating with Treeline to license, develop or commercialize current or future product candidates.

In addition, the patent prosecution process is expensive and time-consuming, and Treeline or Treeline’s licensors may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. In addition, the scope of the claims initially submitted for examination may be significantly narrowed by the time they issue, if at all. It is also possible that Treeline or Treeline’s licensors will fail to identify patentable aspects of Treeline’s research and development output before it is too late to obtain patent protection. Treeline cannot provide any assurances that Treeline will be able to pursue or obtain additional patent protection based on Treeline’s research and development efforts, or that any such patents or other intellectual property Treeline generates will provide any competitive advantage. Moreover, Treeline may not have the right to control the preparation, filing and prosecution of patent applications, or to control the maintenance of the patents, covering technology that Treeline licenses from third parties. Therefore, these patents and applications may not be filed, prosecuted or maintained in a manner consistent with the best interests of Treeline’s business.

Even if Treeline acquires patent protection that Treeline expects should enable Treeline to maintain competitive advantage, the issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability. Third parties, including former employees, consultants, collaborators and competitors, may challenge the inventorship, scope, validity, or enforceability thereof, which may result in such patents being narrowed, invalidated or held unenforceable. If issued, Treeline’s patents may be challenged in patent offices in the United States and abroad, or in court. For example, Treeline may be subject to Post Grant Review or Inter Partes Review proceedings to the U.S. Patent Trial and Appeal Board challenging the validity of one or more claims of Treeline’s patents, once issued. Such submissions may also be made prior to a patent’s issuance, precluding the granting of a patent based on one of Treeline’s patent applications. Treeline may become involved in opposition, reexamination, inter partes review, post-grant review, derivation, or similar proceedings in the United States or abroad challenging the claims of Treeline’s patents, once issued. Furthermore, patents may be challenged in court, once issued. Competitors may have filed patent applications before the inventors of Treeline’s patents did. A competitor may also claim that Treeline is infringing its patents and that Treeline therefore cannot practice Treeline’s technology as claimed under Treeline’s patent applications and patents, if issued. As a result, one or more claims of Treeline’s patents may be narrowed or invalidated. In litigation, a competitor could claim that Treeline’s patents, if issued, are not valid for a number of reasons. If a court agrees, Treeline would lose Treeline’s rights to those challenged patents.

Even if they are unchallenged, Treeline’s patents and pending patent applications, if issued, may not provide Treeline with any meaningful protection or prevent competitors from designing around Treeline’s patent claims to circumvent Treeline’s patents by developing similar or alternative technologies or therapeutics in a non-infringing manner. For example, even if Treeline has a valid and enforceable patent, Treeline may not be able to exclude others from practicing Treeline’s invention if the other party can show that they used the invention in commerce before Treeline’s filing date or the other party benefits from an ex-U.S. compulsory license. If the patent protection provided by the patents and patent applications Treeline holds or pursues with respect to Treeline’s product candidates is not sufficiently broad to impede such competition, Treeline’s ability to successfully commercialize Treeline’s product candidates could be negatively affected, which would harm Treeline’s business.

Certain regulatory exclusivities may be available. However, the scope of such regulatory exclusivities is subject to change, and may not provide Treeline with adequate and continuing protection sufficient to exclude others from commercializing products similar to Treeline’s product candidates.

In addition to patent protection, Treeline relies on the protection of Treeline’s trade secrets, unpatented know-how, technology and other proprietary information to maintain Treeline’s competitive position. Although Treeline has taken steps to protect Treeline’s trade secrets and unpatented know-how, including entering into confidentiality agreements with third parties, and confidential information and inventions agreements with employees, consultants and advisors, Treeline cannot provide any assurances that any party thereto will not breach the agreement and disclose Treeline’s proprietary information, including Treeline’s trade secrets, and Treeline may

not be able to obtain adequate remedies for such breaches. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and outside the United States are less willing or unwilling to protect trade secrets.

Moreover, third parties may still obtain this information or may come upon this or similar information independently, and Treeline would have no right to prevent them from using that technology or information to compete with Treeline. If any of these events occurs or if Treeline otherwise loses protection for Treeline’s trade secrets, the value of this information may be greatly reduced, and Treeline’s competitive position could be harmed. If Treeline does not apply for patent protection prior to such publication or if Treeline cannot otherwise maintain the confidentiality of Treeline’s proprietary technology and other confidential information, then Treeline’s ability to obtain patent protection or to protect Treeline’s trade secret information may be jeopardized.

Treeline is party to license agreements with third parties, including its license agreement with Hengrui (the “Hengrui License Agreement”) and its license agreement with the CRT Pioneer Fund LP (the “CRT License Agreement”) that enables Treeline to utilize third-party intellectual property for the development and commercialization of certain of Treeline’s product candidates, and Treeline may in the future enter into more such license agreements with third parties under which Treeline licenses the use, development and commercialization rights to current or future product candidates or technology from third parties.

These intellectual property license agreements may require Treeline to comply with various obligations, including diligence obligations such as development and commercialization obligations, as well as potential royalty and milestone payments and other obligations. If Treeline fails to comply with its obligations under any of these license agreements, uses the licensed intellectual property in an unauthorized manner, becomes subject to bankruptcy-related proceedings or otherwise materially breaches any of these license agreements, the terms of the license granted may be materially modified, such as by rendering currently exclusive licenses non-exclusive, or it may give Treeline’s licensors the right to terminate the applicable license agreement, in whole or in part. Generally, the loss of or termination of Treeline’s rights under the license agreement, or any other licenses Treeline may acquire in the future, could harm Treeline’s business, financial condition, results of operations and prospects.

Treeline may also, in the future, enter into license agreements with third parties under which Treeline is a sublicensee. If Treeline’s sublicensor fails to comply with its obligations under its upstream license agreement with its licensor, the licensor may have the right to terminate the upstream license, which may result in termination of Treeline’s sublicense. If this were to occur, Treeline would no longer have rights to the applicable intellectual property unless Treeline is able to secure Treeline’s own direct license with the owner of the relevant rights, which Treeline may not be able to do on reasonable terms, or at all, which may impact Treeline’s ability to continue to develop and commercialize product candidates incorporating the relevant intellectual property.

Licensing of intellectual property is important to Treeline’s business and involves complex legal, business and scientific issues. Disputes may arise between Treeline and Treeline’s licensors regarding intellectual property subject to a license agreement, including: