9. Debt

June 2026 Convertible Notes Offering

On June 3, 2026, the Company entered into an underwriting agreement (the “2032 Note Underwriting Agreement”) with Jefferies, J.P. Morgan Securities LLC, TD Securities (USA) LLC and Guggenheim Securities, LLC (the "2032 Underwriters"), subject to customary conditions, to issue and sell in a public offering $500.0 million aggregate principal amount of the 2032 Notes to the 2032 Underwriters (the “2032 Note Offering”). In addition, pursuant to the 2032 Note Underwriting Agreement, the Company granted the 2032 Underwriters an option to purchase up to an additional $75.0 million aggregate principal amount of the 2032 Notes, solely to cover over-allotments. On June 4, 2026, the 2032 Underwriters exercised such option in full. The issuance of $575.0 million aggregate principal amount of the 2032 Notes was completed on June 8, 2026.

The 2032 Notes were issued pursuant to, and are governed by, an indenture (the “Base Indenture”), dated as of August 1, 2025, between the Company and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”), as supplemented by a second supplemental indenture (the “Second Supplemental Indenture,” and the Base Indenture, as supplemented by the Second Supplemental Indenture, the “2032 Indenture”), dated as of June 8, 2026, between the Company and the Trustee. The net proceeds from the 2032 Note Offering, after deducting underwriting discounts and commissions and offering expenses, were $557.2 million, including the proceeds from the 2032 Underwriters’ exercise of their over-allotment option in full.

The 2032 Notes are general, unsecured, senior obligations of the Company. The 2032 Notes accrue interest payable semi-annually in arrears on February 1 and August 1 of each year, beginning on February 1, 2027, at a rate equal to 0.250% per year. In addition, special interest will accrue on the 2032 Notes upon the occurrence of certain events relating to the Company’s failure to file certain reports with the SEC as provided in the 2032 Indenture and as described below. The 2032 Notes also have customary provisions relating to the occurrence of “Events of Default” (as defined in the 2032 Indenture) with certain interest penalty provisions. The 2032 Notes mature on August 1, 2032, unless earlier converted, redeemed or repurchased by the Company.

Noteholders may convert their 2032 Notes at their option at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date based on an initial conversion rate of 8.0302 shares of common stock, per $1,000 principal amount of the 2032 Notes, which is equivalent to an initial conversion price of $124.53 per share of common stock. The conversion rate is subject to customary adjustments upon the occurrence of certain events as described in the 2032 Indenture. In addition, if certain corporate events that constitute a “Make-Whole Fundamental Change” (as defined in the 2032 Indenture) occur, then the conversion rate will, in certain circumstances, be increased for a specified period of time.

The 2032 Notes will be redeemable, in whole or in part (subject to certain limitations described below), at the Company’s option at any time, and from time to time, on a redemption date on or after August 6, 2029, and on or before the 31st scheduled trading day immediately before the maturity date, at a cash redemption price equal to the principal amount of the 2032 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of common stock exceeds 130% of the conversion price on (i) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (ii) the trading day immediately before the date the Company sends such notice. However, the Company may not redeem less than all of the outstanding 2032 Notes unless at least $50.0 million aggregate principal amount of the 2032 Notes are outstanding and not called for redemption as of the time the Company sends the related redemption notice. In addition, calling any 2032 Note for redemption will constitute a Make-Whole Fundamental Change with respect to that 2032 Note, in which case the conversion rate applicable to the conversion of that 2032 Note will be increased in certain circumstances if it is converted after it is called for redemption.

If a “Fundamental Change” (as defined in the 2032 Indenture) occurs, then, subject to certain conditions and except as set forth in the 2032 Indenture, noteholders may require the Company to repurchase their 2032 Notes at a cash repurchase price equal to the principal amount of the 2032 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. The definition in the 2032 Indenture of a Fundamental Change includes certain business combination transactions involving the Company and certain de-listing events with respect to the common stock.

The fair value of the 2032 Notes, which differs from their carrying value, is influenced by interest rates, stock price and stock price volatility and is determined by prices for the 2032 Notes observed in market trading. The market for trading of the 2032 Notes is not considered to be an active market and therefore the fair value is determined using Level 2 inputs. As of June 30, 2026, the carrying value and fair value of the 2032 Notes was $557.4 million and $655.6 million, respectively.

The issuance costs attributed to the 2032 Notes amounted to $17.8 million and were discounted from the 2032 Notes. The issuance costs will be amortized to interest expense over the term of the 2032 Notes based on the effective interest rate method. During each of the three and six months ended June 30, 2026, the effective interest rate was 0.8%. Interest expense related to the 2032 Notes was $0.3 million for each of the three and six months ended June 30, 2026, including $0.2 million related to the amortization of issuance costs.

As of June 30, 2026, the Company was in full compliance with all financial covenants under the 2032 Notes.

July 2025 Convertible Notes Offering

On July 30, 2025, the Company entered into an underwriting agreement (the “2031 Note Underwriting Agreement”) with the 2031 Underwriters, subject to customary conditions, to issue and sell in a public offering $175.0 million aggregate principal amount of the 2031 Notes to the 2031 Underwriters (the “2031 Note Offering”). In addition, pursuant to the 2031 Note Underwriting Agreement, the Company granted the 2031 Underwriters an option to purchase up to an additional $26.3 million aggregate principal amount of the 2031 Notes, solely to cover over-allotments. On July 30, 2025, the 2031 Underwriters exercised such option in full. The issuance of $201.3 million aggregate principal amount of the 2031 Notes was completed on August 1, 2025.

The 2031 Notes were issued pursuant to, and are governed by the Base Indenture, as supplemented by a first supplemental indenture (the “First Supplemental Indenture,” and the Base Indenture, as supplemented by the First Supplemental Indenture, the “2031 Indenture”), dated as of August 1, 2025, between the Company and the Trustee. The net proceeds from the 2031 Note Offering, after deducting underwriting discounts and commissions and offering expenses, were $194.9 million, including the proceeds from the 2031 Underwriters’ exercise of their over-allotment option in full.

The 2031 Notes are general, unsecured, senior obligations of the Company. The 2031 Notes accrue interest payable semi-annually in arrears on February 1 and August 1 of each year, beginning on February 1, 2026, at a rate equal to 2.750% per year. In addition, special interest will accrue on the 2031 Notes upon the occurrence of certain events relating to the Company’s failure to file certain reports with the SEC as provided in the 2031 Indenture and as described below. The 2031 Notes also have customary provisions relating to the occurrence of “Events of Default” (as defined in the 2031 Indenture) with certain interest penalty provisions. The 2031 Notes mature on August 1, 2031, unless earlier converted, redeemed or repurchased by the Company.

Noteholders may convert their 2031 Notes at their option at any time prior to the close of business on the scheduled trading day immediately preceding the maturity date based on an initial conversion rate of 19.4932 shares of common stock, per $1,000 principal amount of the 2031 Notes, which is equivalent to an initial conversion price of $51.30 per share of common stock. The conversion rate is subject to customary adjustments upon the occurrence of certain events as described in the 2031 Indenture. In addition, if certain corporate events that constitute a “Make-Whole Fundamental Change” (as defined in the 2031 Indenture) occur, then the conversion rate will, in certain circumstances, be increased for a specified period of time.

The 2031 Notes will be redeemable, in whole or in part (subject to certain limitations described below), at the Company’s option at any time, and from time to time, on a redemption date on or after August 6, 2029, and on or before the 51st scheduled trading day immediately before the maturity date, at a cash redemption price equal to the principal amount of the 2031 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of the common stock exceeds 130% of the conversion price on (i) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice; and (ii) the trading day immediately before the date the Company sends such notice. However, the Company may not redeem less than all of the outstanding 2031 Notes unless at least $50.0 million aggregate principal amount of the 2031 Notes are outstanding and not called for redemption as of the time the Company sends the related redemption notice. In addition, calling any 2031 Note for redemption will constitute a Make-Whole Fundamental Change with respect to that 2031 Note, in which case the conversion rate applicable to the conversion of that 2031 Note will be increased in certain circumstances if it is converted after it is called for redemption.

If a “Fundamental Change” (as defined in the 2031 Indenture) occurs, then, subject to certain conditions and except as set forth in the 2031 Indenture, noteholders may require the Company to repurchase their 2031 Notes at a cash repurchase price equal to the principal amount of the 2031 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. The definition in the 2031 Indenture of a Fundamental Change includes certain business combination transactions involving the Company and certain de-listing events with respect to the common stock.

The 2031 Notes contain a beneficial ownership limitation, and as a result of such limitation, noteholders do not have the right to convert all or any portion of the 2031 Notes held by such noteholder, to the extent that immediately prior to, or immediately after giving effect to such conversion by such noteholder, together with its affiliates and any other persons acting as a group together with such noteholder or any of such noteholder’s affiliates, would beneficially own in excess of 4.99% of the number of shares of the Company’s common stock outstanding immediately prior to, and immediately after giving effect to, the conversion of all or any portion of the 2031 Notes; provided, that such 4.99% beneficial ownership can be increased or decreased at the discretion of the noteholder; provided further, that such limitation in no event can exceed 19.99%.

The fair value of the 2031 Notes, which differs from their carrying value, is influenced by interest rates, stock price and stock price volatility and is determined by prices for the 2031 Notes observed in market trading. The market for trading of the 2031 Notes is not considered to be an active market and therefore the fair value is determined using Level 2 inputs. As of June 30, 2026, the carrying value and fair value of the 2031 Notes was $195.8 million and $422.2 million, respectively. As of December 31, 2025, the carrying value and fair value of the 2031 Notes was $195.3 million and $436.5 million, respectively.

The issuance costs attributed to the 2031 Notes amounted to $6.4 million and were discounted from the 2031 Notes. The issuance costs will be amortized to interest expense over the term of the 2031 Notes based on the effective interest rate method. During each of the three and six months ended June 30, 2026, the effective interest rate was 3.3%. During the three and six months ended June 30, 2026, interest expense related to the 2031 Notes was $1.6 million and $3.3 million, respectively, including $0.2 million and $0.5 million, respectively, related to the amortization of issuance costs.

As of June 30, 2026, the Company was in full compliance with all financial covenants under the 2031 Notes.

Amended and Restated Loan and Security Agreement

Third Amendment

On September 9, 2025, the Company entered into the Third Amendment (the “Third Amendment”) to the Amended and Restated Loan and Security Agreement (the “A&R Loan Agreement”) with Oxford Finance LLC, a Delaware limited liability company (“Oxford”), as collateral agent and a lender, Innovatus Life Sciences Lending Fund I, LP, a Delaware limited partnership (“Innovatus”), as a lender, and the other lenders party thereto (together with Oxford and Innovatus, the “Lenders”), pursuant to which the A&R Loan Agreement was amended to (i) replace Innovatus with Oxford as collateral agent; (ii) recognize the achievement of the Term D Milestone (as defined in the A&R Loan Agreement, as amended by the Third Amendment (the “Amended A&R Loan Agreement”)) and provide for the immediate disbursement of the $30.0 million Term D Loan (as defined in the Amended A&R Loan Agreement); (iii) increase the size of the Term E Loan (as defined in the Amended A&R Loan Agreement) from $50.0 million to up to $100.0 million, which Term E Loan could only have been drawn upon FDA approval of gedatolisib in second line WT ABC patients post CDK4/6 inhibitor therapy; (iv) add three new up to $40.0 million Term F Loans (as defined in the Amended A&R Loan Agreement), for a total of $120.0 million, which could only have been drawn upon achievement of certain trailing three months’ product revenue thresholds; (v) replace the prior $45.0 million Term F Loan (as defined in the A&R Loan Agreement) with a new $150.0 million Term G Loan (as defined in the Amended A&R Loan Agreement), which continued to be available only in the Lenders’ sole discretion upon the Company’s request; (vi) require an amendment fee payable by the Company to the Lenders in the amount of $0.1 million, which was paid at the closing of the Third Amendment; (vii) make certain revisions to the non-utilization fee for the Term E Loan, and add a new non-utilization fee for the Term F Loans, in each case equal to 3% of the applicable unfunded commitment, after taking into consideration any reductions to the applicable term loan commitment that the Company may make by notice to the collateral agent before the date that is eight weeks after the achievement of any applicable milestones; and (viii) extend the maturity date of the term loans to November 1, 2029. The Term E Loan and each Term F Loan also were subject to other customary conditions and limits on when the Company could request funding. With the disbursement of the $30.0 million Term D Loan, the Company received net proceeds of $27.7 million.

In accordance with the Amended A&R Loan Agreement, a Final Fee of $1.4 million, equal to 4.5% of the $30.0 million Term D Loan, was recognized.

In connection with the Third Amendment, the Company issued warrants with an exercise price of $14.84 per share to purchase an aggregate of 50,537 shares of the Company’s common stock to Innovatus, Oxford, and certain of its affiliates (the “Third Amendment Warrants”). The Third Amendment Warrants may be exercised on a cashless basis and are exercisable through the tenth anniversary of the funding date of the Term D Loan. The number of shares of common stock for which each Third Amendment Warrant is exercisable and the associated exercise price are subject to certain proportional adjustments as set forth in such Third Amendment Warrant.

A portion of the proceeds from the Term D Loan in the amount of $2.8 million was allocated to the Third Amendment Warrants based on their relative fair value to the underlying Term D Loan. The proceeds allocated to the Third Amendment Warrants were recorded as additional paid in capital in the accompanying condensed balance sheets and were discounted from the Term D Loan. The relative fair value of the Third Amendment Warrants was based on the Black-Scholes model with the following assumptions: risk-free interest rate of 4.1%; expected volatility of 74.4%; expected life of 10.0 years; and expected dividend yield of 0%. The underlying stock price used in the analysis was the traded market price. The discount related to the Third Amendment Warrants is being amortized to interest expense ratably over the term of the Term D Loan.

Second Amendment

On July 28, 2025, the Company entered into the Second Amendment (the “Second Amendment”) to the A&R Loan Agreement with Innovatus, as collateral agent, and the Lenders including Innovatus in its capacity as a Lender and Oxford, pursuant to which Innovatus and Oxford, as Lenders, agreed to make certain term loans (“Term Loans”) to the Company in the aggregate principal amount of up to $180.0 million. The A&R Loan Agreement was amended to (i) subject to certain terms and conditions, permit the issuance of the 2031 Notes discussed above and certain transactions in connection therewith, including the conversion thereof settled solely in common stock (together with cash in lieu of the issuance of any fractional share of common stock), (ii) permit capped call transactions in connection with the pricing of the 2031 Notes, (iii) require an amendment fee payable by the Company to Oxford in the amount of less than $0.1 million, which was paid upon execution of the Second Amendment, and (iv) extend to May 9, 2026, the expiration date of Innovatus’ right to convert up to 20% of the outstanding principal of the Term A Loan into shares of the Company’s common stock at a price per share of $10.00.

On May 1, 2026, Innovatus converted $3,438,029 of the outstanding principal of the Term A Loan into 343,802 shares of the Company’s common stock.

Further, in connection with the release of the topline data from the WT cohort of the VIKTORIA-1 Phase 3 trial, the Company achieved the Term D Milestone (as defined in the A&R Loan Agreement) and therefore became eligible to draw an additional $30.0 million of indebtedness under the Term D Loan (as defined in the A&R Loan Agreement). As described above, the Term D Loan was disbursed to the Company in connection with the Third Amendment.

First Amendment

On May 13, 2025, the Company entered into the First Amendment (the “First Amendment”) to the A&R Loan Agreement, pursuant to which the Company agreed to (i) pay Oxford an amendment fee of less than $0.1 million on the effective date of the First Amendment, (ii) extend to March 9, 2026 the expiration date of Innovatus’ right to convert up to 20% of the outstanding principal of the Term A Loan into shares of the Company’s common stock at a price per share of $10.00, (iii) extend the expiration date of the Term D Draw Period to the earlier of (x) August 31, 2025 and (y) the occurrence of an Event of Default (as defined in the A&R Loan Agreement), (iv) update the liquidity covenant to increase the Minimum Liquidity Percentage (as defined in the First Amendment) to 50% if the Company had failed to achieve the Term D Milestone prior to June 1, 2025, and to decrease the Minimum Liquidity Percentage back to 30% if the Company had subsequently achieved the Term D Milestone prior to the end of the Term D Draw Period, and (v) release Innovatus and the Lenders from any and all claims arising out of or related to the A&R Loan Agreement, the First Amendment and related documentation.

Amended and Restated Loan Agreement

On May 30, 2024, the Company entered into the A&R Loan Agreement, which amended and restated, in its entirety, the April 8, 2021 Loan and Security Agreement between the Company and Innovatus, as collateral agent, and the Lenders named therein (the “Prior Loan Agreement”).

Pursuant to the A&R Loan Agreement, the Company was entitled to make interest-only payments for thirty-six months, or up to forty-eight months if certain conditions had been met. The Term Loans bore interest at a rate equal to the sum of (a) the greater of (i) the Prime Rate (as defined in the A&R Loan Agreement) or (ii) 7.75%, plus (b) 2.85%, provided that 1.0% of such interest was payable in-kind by adding an amount equal to such 1.0% of the outstanding principal amount to the then outstanding principal balance on a monthly basis through May 31, 2027. The A&R Loan Agreement was secured by all assets of the Company. Proceeds were used- for working capital purposes and to fund the Company’s general business requirements, including the VIKTORIA-1 Phase 3 trial, the CELC-G-201 Phase 1b/2 trial, and the VIKTORIA-2 Phase 3 trial. The A&R Loan Agreement contained customary representations and warranties and covenants, subject to customary carve-outs, and included financial covenants related to liquidity and other financial measures. Prior to the Second Amendment, Innovatus also had the right, at its election and until August 9, 2025, to convert up to 20% of the outstanding principal of the Term A Loan into shares of the Company’s common stock at a price per share of $10.00.

The A&R Loan Agreement contained a Final Fee, which is equal to 4.5% of the initial funding of the agreement and was due on the earliest to occur of (a) the Maturity Date, (b) the acceleration of any Term Loan, and (c) the prepayment of the Term Loans. There was also a contingent non-utilization fee for the Term E Loans. Following the disbursement of the Term D Loan in connection with the Third Amendment, the non-utilization provisions related to the Term D Loan are no longer operative. The Term D Loan became due and payable on the earliest of (i) the termination of the Term D Draw Period, (ii) the Maturity Date, (iii) the acceleration of any Term Loan, and (iv) the prepayment in whole of the Term Loans. If the Company had achieved the Term E Milestone and (i) failed to draw the full amount of the Term E Loan during the Term E Draw Period and (ii) failed to notify collateral agent, at any time before the date that was four weeks after the Company’s achievement of the Term E Milestone, of the Company’s intent not to draw the full amount of the Term E Loan, a non-utilization fee with respect to the Term E Loan would have become due and payable on the earliest of (i) the termination of the Term E Draw Period, (ii) the Maturity Date, (iii) the acceleration of any Term Loan, and (iv) the prepayment in whole of the Term Loans. After the 18-month anniversary of the Effective Date, the Company had the option to prepay all, but not less than all, of the Term Loans advanced by the Lenders under the A&R Loan Agreement, provided the Company (i) provided written notice to collateral agent of its election to prepay the Term Loans at least seven business days prior to such prepayment, and (ii) paid to Lenders on the date of such prepayment, payable to each Lender in accordance with its respective Pro Rata Share, an amount equal to the sum of (A) all outstanding principal of the Term Loans plus accrued and unpaid interest thereon through the prepayment date, (B) the Final Fee, (C) the Prepayment Fee, plus (D) all other outstanding Obligations that were due and payable, including, without limitation, Lenders’ Expenses and interest at the Default Rate with respect to any past due amounts.

The Company evaluated the change of terms under ASC 470-50, Debt – Modification and Extinguishment, with respect to the Third Amendment, the Second Amendment, the First Amendment and the A&R Loan Agreement and concluded the change in terms did not result in significant and consequential changes to the economic substance of the debt and thus resulted in a modification of the debt and not an extinguishment of the debt.

Voluntary Prepayment

On June 8, 2026, the Company utilized $137.4 million of the net proceeds from the 2032 Notes to complete a voluntary prepayment of all outstanding principal, accrued and unpaid interest, fees, costs and expenses under the Amended A&R Loan Agreement (the “Payoff Amount”). Upon receipt by the Lenders of the Payoff Amount on June 8, 2026, all obligations, covenants, debts and liabilities of the Company under the Amended A&R Loan Agreement were satisfied and discharged in full, and the Amended A&R Loan Agreement and all other documents entered into in connection with the Amended A&R Loan Agreement, were terminated. In connection with the termination of the Amended A&R Loan Agreement, the Company wrote off $7.3 million of unamortized discounts and incurred a loss on debt extinguishment of $11.5 million, which was included in other expense in the Company's condensed statements of operations.

As of December 31, 2025, the fair value of the note payable, which differed from its carrying value, was $160.2 million. The fair value of the note payable was determined using the Company’s estimated discount rate, volatility and risk-free rate, which are considered Level 3 inputs.

The debt issuance costs and discount were being amortized to interest expense over the term of the Amended A&R Loan Agreement based on the effective interest rate method. During the six months ended June 30, 2026 and 2025, the effective interest rate was 12.7% and 12.3%, respectively. During the three months ended June 30, 2026 and 2025, interest expense related to the note payable was $3.5 million and $3.2 million, respectively, including $0.4 million and $0.3 million, respectively, related to debt issuance costs and discount amortization. During the six months ended June 30, 2026 and 2025, interest expense related to the note payable was $7.9 million and $6.4 million, respectively, including $0.9 million and $0.6 million, respectively, related to debt issuance costs and discount amortization.

As of June 30, 2026, there are no future payments or financial covenants under the Amended A&R Loan Agreement.