Commitments and Contingencies	3 Months Ended
Mar. 31, 2026
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Leases There have been no material changes to the Company’s lease agreement during the three months ended March 31, 2026. For additional information on the Company's operating leases, see Note 7, Leases, of the consolidated financial statements in the Annual Report. License Agreements (Budoprutug) On June 27, 2024, the Company completed its acquisition (the Acquisition) of Tenet Medicines, Inc. (Tenet). As a result of the Acquisition, the following legacy Tenet agreements effectively became agreements of the Company. Acelyrin Asset Purchase Agreement On January 11, 2024, Tenet entered into an asset purchase agreement (the Asset Purchase Agreement) with Acelyrin, Inc. (Acelyrin) and WH2, LLC, which was subsequently transferred to the Company by operation of law upon the closing of the Acquisition, providing for the acquisition of certain assets of Acelyrin related to budoprutug, including certain assigned contracts. Under these assigned contracts, the Company received worldwide license (with the right to sublicense) rights to develop, manufacture, use and commercialize budoprutug for any non-oncology indication, and assumed certain liabilities of Acelyrin. In addition, the Company inherited the rights and obligations, including financial obligations, under the CRH Agreement (as defined below) and the ProBioGen Agreement (as defined below). In consideration for the license and other rights the Company received under the Asset Purchase Agreement with respect to Products (as such term is defined in the Asset Purchase Agreement), the Company is obligated to (i) make total payments of up to $157.5 million to Acelyrin upon the achievement of various development, regulatory and commercial milestones, (ii) pay royalties in the single-digit percentages, subject to specified reductions, to Acelyrin on worldwide net sales in a given calendar year, and (iii) make non-refundable and non-creditable payments to Acelyrin on sublicense income with rates ranging from the low single digit to mid teen percent depending on the stage of development of the most advanced Product at the time of such sublicense. On December 31, 2025, the Company filed a complaint in Delaware Superior Court against Alumis Inc. and its wholly owned subsidiary, Acelyrin, relating to a dispute concerning potential milestone payments owed under the Asset Purchase Agreement as further described below under Legal Proceedings. The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. As of March 31, 2026, the Company has not recorded expense related to milestone payments under the Asset Purchase Agreement. For additional information related to the Asset Purchase Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report. CRH Agreement In connection with the Asset Purchase Agreement, in January 2024 Tenet was assigned a license agreement with Cancer Research Technology Limited (CRH) and, in connection with such assignment, Tenet entered into an amended and restated license agreement with CRH (the CRH Agreement) which was subsequently transferred to the Company by operation of law upon the closing of the Acquisition. The CRH Agreement granted the Company a worldwide exclusive license (other than specified patent rights and materials, which are licensed to the Company on a non-exclusive basis) to research, develop, test, manufacture or sell certain licensed products related to budoprutug, for all therapeutic uses except for oncology indications. The Company is permitted to grant a sublicense under these licenses with CRH’s prior written consent. The Company is obligated to pay CRH a mid-five figure digit fee on each anniversary of the effective date and up to an aggregate of £106.8 million ($141.2 million as of March 31, 2026) upon the achievement of specified development, regulatory, commercial and sales milestone events, including: (i) payments of up to mid-six figure digits in pounds sterling for certain development milestones, (ii) payments of up to low-eight figures in pounds sterling per indication (for up to three indications) for certain regulatory and commercial milestones and (iii) payments up to mid-eight figures in pounds sterling for certain sales milestones. The Company is also obligated to pay tiered royalties ranging from a rate in the mid-single digit to high-single digit percentage on net sales. The Company is also responsible for a sublicensing revenue payment ranging from a rate in the mid-single digit to mid-double digits for any sublicense revenue. The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. During the three months ended March 31, 2026 and 2025, the Company did not recognize any research and development expense related to the milestones. For additional information related to the CRH Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report. ProBioGen Agreement Under the Asset Purchase Agreement, Tenet was assigned a cell line development, manufacturing services and license agreement (the ProBioGen Agreement) originally entered into by ValenzaBio, Inc. and ProBioGen AG (ProBioGen) in February 2021, which was subsequently transferred to the Company by operation of law upon the closing of the Acquisition. The ProBioGen Agreement granted the Company a non-exclusive license to use cell lines in which ProBioGen’s proprietary technology is applied, to research, develop, manufacture, use, sell, offer to sell, import or export budoprutug. This license includes a non-exclusive sublicense by ProBioGen of certain third-party patent rights, limited to the use of budoprutug. The Company is obligated to (i) make payments of up to €10.0 million ($11.5 million as of March 31, 2026) upon the achievement of certain development, manufacturing and commercial milestones, including the start of a Phase 2 clinical trial for budoprutug, and (ii) make milestone payments of up to €7.0 million ($8.0 million as of March 31, 2026) upon the achievement of certain sales milestones. If the Company elects to contract ProBioGen to perform certain manufacturing services for budoprutug, the milestone payments would be reduced by €1.1 million ($1.2 million as of March 31, 2026). The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. During the three months ended March 31, 2026 and 2025, the Company did not recognize any research and development expense related to the milestones. For additional information related to the ProBioGen Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report. License Agreement (CLYM116) On January 8, 2025, the Company entered into the Mabworks Agreement pursuant to which Mabworks granted to the Company (i) an exclusive (even as to Mabworks and its affiliates), sublicensable right and license under certain patent rights and related know-how (the Licensed Intellectual Property) to develop, manufacture and commercialize Mabworks’ proprietary antibodies associated with Mabworks’ proprietary antibody program, CLYM116 and products containing CLYM116 (Licensed Products) outside of mainland China, Hong Kong, Macau, and Taiwan (Greater China), (ii) a non-exclusive, sublicensable right and license under the Licensed Intellectual Property to manufacture CLYM116 and Licensed Products in Greater China (the Licensed Territory) and (iii) a non-exclusive, sublicensable right and license under the Licensed Intellectual Property to develop CLYM116 and Licensed Products in Greater China in connection with certain global clinical studies (as described below). Under the terms of the Mabworks Agreement, the Company paid to Mabworks a $9.0 million upfront payment, and the Company is obligated to pay a total of up to $30.0 million upon the achievement of certain development and regulatory milestones pertaining to the first indication for a Licensed Product, additional lower amounts upon the achievement of certain development and regulatory milestones pertaining to up to two additional indications for a Licensed Product and a total of up to $832.0 million upon the achievement of certain commercial milestones for all Licensed Products. In addition, the Company is obligated to pay Mabworks tiered royalties in the low-to mid-single-digit percentages on aggregate annual net sales of all Licensed Products in the Licensed Territory. The Company recorded the upfront payment of $9.0 million as research and development expenses in the first quarter of 2025 in the unaudited condensed consolidated statements of operations and comprehensive loss. The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. During the three months ended March 31, 2026, the Company did not record any research and development expense related to a milestone. For additional information related to the Mabworks Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report. Legal Proceedings From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company records accruals for estimated losses when available information indicates a loss is probable and reasonably estimable. Significant judgment is required to determine both probability and the estimated amount. The Company expenses the costs related to its legal proceedings as they are incurred. On December 31, 2025, the Company filed a complaint in Delaware Superior Court against Alumis Inc. and its wholly owned subsidiary, Acelyrin, relating to a dispute concerning potential milestone payments owed under the Asset Purchase Agreement seeking a declaratory judgment that the Company’s budoprutug drug candidate is not a Product under the Asset Purchase Agreement, and that the Company does not owe a milestone payment sought by Alumis in connection with its development of budoprutug. This matter is currently pending. The Company is unable to predict the timeline for resolution or the outcome of this matter. As of the date of these unaudited condensed consolidated financial statements, the Company is not party to any other material legal matters or claims. Indemnification In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless, and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. In addition, the Company has entered into indemnification agreements with members of its board of directors and executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. To date, the Company has not incurred any material costs as a result of such indemnification provisions. The Company is not currently aware of any indemnification claims and has not accrued any liabilities related to such obligations in its unaudited condensed consolidated financial statements as of March 31, 2026.

Commitments and Contingencies

3 Months Ended

Mar. 31, 2026

Commitments and Contingencies Disclosure [Abstract]

6. Commitments and Contingencies

Leases

There have been no material changes to the Company’s lease agreement during the three months ended March 31, 2026. For additional information on the Company's operating leases, see Note 7, Leases, of the consolidated financial statements in the Annual Report.

License Agreements (Budoprutug)

On June 27, 2024, the Company completed its acquisition (the Acquisition) of Tenet Medicines, Inc. (Tenet). As a result of the Acquisition, the following legacy Tenet agreements effectively became agreements of the Company.

Acelyrin Asset Purchase Agreement

On January 11, 2024, Tenet entered into an asset purchase agreement (the Asset Purchase Agreement) with Acelyrin, Inc. (Acelyrin) and WH2, LLC, which was subsequently transferred to the Company by operation of law upon the closing of the Acquisition, providing for the acquisition of certain assets of Acelyrin related to budoprutug, including certain assigned contracts. Under these assigned contracts, the Company received worldwide license (with the right to sublicense) rights to develop, manufacture, use and commercialize budoprutug for any non-oncology indication, and assumed certain liabilities of Acelyrin.

In addition, the Company inherited the rights and obligations, including financial obligations, under the CRH Agreement (as defined below) and the ProBioGen Agreement (as defined below).

In consideration for the license and other rights the Company received under the Asset Purchase Agreement with respect to Products (as such term is defined in the Asset Purchase Agreement), the Company is obligated to (i) make total payments of up to $157.5 million to Acelyrin upon the achievement of various development, regulatory and commercial milestones, (ii) pay royalties in the single-digit percentages, subject to specified reductions, to Acelyrin on worldwide net sales in a given calendar year, and (iii) make non-refundable and non-creditable payments to Acelyrin on sublicense income with rates ranging from the low single digit to mid teen percent depending on the stage of development of the most advanced Product at the time of such sublicense.

The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. As of March 31, 2026, the Company has not recorded expense related to milestone payments under the Asset Purchase Agreement.

For additional information related to the Asset Purchase Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report.

CRH Agreement

In connection with the Asset Purchase Agreement, in January 2024 Tenet was assigned a license agreement with Cancer Research Technology Limited (CRH) and, in connection with such assignment, Tenet entered into an amended and restated license agreement with CRH (the CRH Agreement) which was subsequently transferred to the Company by operation of law upon the closing of the Acquisition. The CRH Agreement granted the Company a worldwide exclusive license (other than specified patent rights and materials, which are licensed to the Company on a non-exclusive basis) to research, develop, test, manufacture or sell certain licensed products related to budoprutug, for all therapeutic uses except for oncology indications. The Company is permitted to grant a sublicense under these licenses with CRH’s prior written consent.

The Company is obligated to pay CRH a mid-five figure digit fee on each anniversary of the effective date and up to an aggregate of £106.8 million ($141.2 million as of March 31, 2026) upon the achievement of specified development, regulatory, commercial and sales milestone events, including: (i) payments of up to mid-six figure digits in pounds sterling for certain development milestones, (ii) payments of up to low-eight figures in pounds sterling per indication (for up to three indications) for certain regulatory and commercial milestones and (iii) payments up to mid-eight figures in pounds sterling for certain sales milestones. The Company is also obligated to pay tiered royalties ranging from a rate in the mid-single digit to high-single digit percentage on net sales. The Company is also responsible for a sublicensing revenue payment ranging from a rate in the mid-single digit to mid-double digits for any sublicense revenue.

The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. During the three months ended March 31, 2026 and 2025, the Company did not recognize any research and development expense related to the milestones.

For additional information related to the CRH Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report.

ProBioGen Agreement

Under the Asset Purchase Agreement, Tenet was assigned a cell line development, manufacturing services and license agreement (the ProBioGen Agreement) originally entered into by ValenzaBio, Inc. and ProBioGen AG (ProBioGen) in February 2021, which was subsequently transferred to the Company by operation of law upon the closing of the Acquisition. The ProBioGen Agreement granted the Company a non-exclusive license to use cell lines in which ProBioGen’s proprietary technology is applied, to research, develop, manufacture, use, sell, offer to sell, import or export budoprutug. This license includes a non-exclusive sublicense by ProBioGen of certain third-party patent rights, limited to the use of budoprutug.

The Company is obligated to (i) make payments of up to €10.0 million ($11.5 million as of March 31, 2026) upon the achievement of certain development, manufacturing and commercial milestones, including the start of a Phase 2 clinical trial for budoprutug, and (ii) make milestone payments of up to €7.0 million ($8.0 million as of March 31, 2026) upon the achievement of certain sales milestones. If the Company elects to contract ProBioGen to perform certain manufacturing services for budoprutug, the milestone payments would be reduced by €1.1 million ($1.2 million as of March 31, 2026).

For additional information related to the ProBioGen Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report.

License Agreement (CLYM116)

On January 8, 2025, the Company entered into the Mabworks Agreement pursuant to which Mabworks granted to the Company (i) an exclusive (even as to Mabworks and its affiliates), sublicensable right and license under certain patent rights and related know-how (the Licensed Intellectual Property) to develop, manufacture and commercialize Mabworks’ proprietary antibodies associated with Mabworks’ proprietary antibody program, CLYM116 and products containing CLYM116 (Licensed Products) outside of mainland China, Hong Kong, Macau, and Taiwan (Greater China), (ii) a non-exclusive, sublicensable right and license under the Licensed Intellectual Property to manufacture CLYM116 and Licensed Products in Greater China (the Licensed Territory) and (iii) a non-exclusive, sublicensable right and license under the Licensed Intellectual Property to develop CLYM116 and Licensed Products in Greater China in connection with certain global clinical studies (as described below).

Under the terms of the Mabworks Agreement, the Company paid to Mabworks a $9.0 million upfront payment, and the Company is obligated to pay a total of up to $30.0 million upon the achievement of certain development and regulatory milestones pertaining to the first indication for a Licensed Product, additional lower amounts upon the achievement of certain development and regulatory milestones pertaining to up to two additional indications for a Licensed Product and a total of up to $832.0 million upon the achievement of certain commercial milestones for all Licensed Products. In addition, the Company is obligated to pay Mabworks tiered royalties in the low-to mid-single-digit percentages on aggregate annual net sales of all Licensed Products in the Licensed Territory.

The Company recorded the upfront payment of $9.0 million as research and development expenses in the first quarter of 2025 in the unaudited condensed consolidated statements of operations and comprehensive loss. The Company records expense related to milestone payments when achievement of the milestone is assessed as probable. During the three months ended March 31, 2026, the Company did not record any research and development expense related to a milestone.

For additional information related to the Mabworks Agreement, please read Note 8, Commitments and Contingencies, to the Company’s audited consolidated financial statements included in the Annual Report.

Legal Proceedings

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company records accruals for estimated losses when available information indicates a loss is probable and reasonably estimable. Significant judgment is required to determine both probability and the estimated amount. The Company expenses the costs related to its legal proceedings as they are incurred.

On December 31, 2025, the Company filed a complaint in Delaware Superior Court against Alumis Inc. and its wholly owned subsidiary, Acelyrin, relating to a dispute concerning potential milestone payments owed under the Asset Purchase Agreement seeking a declaratory judgment that the Company’s budoprutug drug candidate is not a Product under the Asset Purchase Agreement, and that the Company does not owe a milestone payment sought by Alumis in connection with its development of budoprutug. This matter is currently pending. The Company is unable to predict the timeline for resolution or the outcome of this matter.

As of the date of these unaudited condensed consolidated financial statements, the Company is not party to any other material legal matters or claims.

Indemnification

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless, and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. In addition, the Company has entered into indemnification agreements with members of its board of directors and executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. To date, the Company has not incurred any material costs as a result of such indemnification provisions. The Company is not currently aware of any indemnification claims and has not accrued any liabilities related to such obligations in its unaudited condensed consolidated financial statements as of March 31, 2026.