Aktis Oncology, Inc.

NOTES TO CONDENSED CONSOLID ATED FINANCIAL STATEMENTS

(In thousands, except for per share and share amounts)

1. Nature of the business and basis of presentation

Aktis Oncology, Inc. (“Aktis” or the “Company”) was incorporated under the laws of the State of Delaware in August 2020. Its principal office is in Boston, Massachusetts. Aktis Security Corporation, its wholly owned subsidiary, was formed under the laws of the State of Delaware in November 2022. The Company is a clinical-stage oncology company focused on unlocking the breakthrough potential of targeted radiopharmaceuticals for large patient populations not currently addressed by existing technologies. The Company has built a proprietary miniprotein radioconjugate platform that aims to safely confer breakthrough efficacy to a broader range of patient populations.

Risks and uncertainties

The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, the outcome of clinical trials, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technologies, compliance with government regulations, ability to secure additional capital to fund operations, and potential delays associated with the Company’s anticipated and planned trials.

There can be no assurance that the Company will be able to successfully complete the development of, or receive regulatory approval for, any products developed, and if approved, that any products will be commercially viable. Any products resulting from the Company’s current research and development efforts will require significant additional research and development, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts will require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance reporting capabilities. The Company has not generated any revenue from the sale of any products to date. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Reverse Stock Split

On January 2, 2026, the Company effected a 1-for-3.8044 reverse stock split of its issued and outstanding common stock, which also resulted in a proportional adjustment to the conversion price for each series of its redeemable convertible preferred stock, and to the exercise prices and number of outstanding stock options. The par value and authorized number of shares of common stock and redeemable convertible preferred stock were not adjusted as a result. All share and per share amounts for all periods presented in the condensed consolidated financial statements and notes thereto have been retroactively adjusted to reflect the effect of the reverse stock split.

Initial Public Offering

In January 2026, the Company completed its initial public offering ("IPO"), in which the Company sold an aggregate of 20,297,500 shares of its common stock at a public offering price of $18.00 per share, including 2,647,500 shares pursuant to the full exercise of the underwriters' option to purchase additional shares, resulting in aggregate net proceeds of approximately $334.4 million, after deducting underwriter discounts, commissions and other offering expenses. Immediately prior to the closing of the IPO, the Company's outstanding redeemable convertible preferred stock automatically converted into 32,184,389 shares of common stock and 1,872,829 shares of Class A non-voting common stock. Following the closing of the IPO, no shares of redeemable convertible preferred stock were outstanding.

In connection with the closing of the IPO, the Company's certificate of incorporation was amended and restated to authorize 480,000,000 shares of common stock, par value $0.0001 per share,10,000,000 shares of Class A common stock, par value $0.0001 per share and 10,000,000 shares of undesignated preferred stock, par value $0.0001 per share.

Liquidity

In accordance with Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties About an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), the Company has evaluated whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the condensed consolidated financial statements are issued. The accompanying condensed consolidated financial statements have been prepared on a going-concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business.

The Company has incurred losses since inception, including net losses of $42.5 million and $33.1 million for thesix months ended June 30, 2026 and 2025, respectively. As of June 30, 2026, the Company had an accumulated deficit of $199.0 million.

The Company has evaluated whether there are certain conditions and events, considered in the aggregate, that raise substantial doubt about the Company's ability to continue as a going concern within the twelve months after the date that these condensed consolidated financial statements are issued. The Company believes that its existing cash, cash equivalents, and marketable securities of $517.3 million as of June 30, 2026, will be sufficient to allow the Company to fund operations at least twelve months from the date that the financial statements are issued.

Basis of presentation and consolidation

The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The accompanying condensed consolidated financial statements include the accounts of the Company’s wholly owned subsidiary, Aktis Security Corporation. All intercompany balances and transactions have been eliminated in consolidation. Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and ASUs of the Financial Accounting Standards Board (“FASB”).

2. Summary of significant accounting policies

The Company’s significant accounting policies are disclosed in Note 2, “Summary of significant accounting policies,” in the audited consolidated annual financial statements in the Annual Report on Form 10-K for the year ended December 31, 2025 (the "Annual Report"), which was filed with the Securities and Exchange Commission ("SEC") on March 30, 2026. Since the date of those annual financial statements, there have been no changes to the Company’s significant accounting policies, except as noted below.

Unaudited interim financial information

The accompanying condensed consolidated balance sheet as of June 30, 2026, and the condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of redeemable convertible preferred stock and stockholders’ equity (deficit) and condensed consolidated statements of cash flows for the six months ended June 30, 2026 and 2025 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the December 31, 2025 and 2024 audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial position as of June 30, 2026. The results for the three and six months ended June 30, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026, or for any other subsequent period.

Recent accounting pronouncements not yet adopted

In November 2024, the FASB issued ASU No. 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures, ("ASU 2024-03"). ASU 2024-03 requires disclosure of additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. The standard is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with prospective or retrospective application and early adoption permitted. The Company is currently evaluating the disclosure requirements related to this new standard.

3. Fair value measurements

The following table sets forth by level, within the fair value hierarchy, the financial assets and liabilities carried at fair value on a recurring basis (in thousands):

During the three and six months ended June 30, 2026, there wereno transfers or reclassifications between fair value measurement levels of financial assets. The carrying values of prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities approximate their fair values due to the short-term nature of these assets and liabilities. The Company had no other financial liabilities for the periods presented above.

Valuation of marketable securities

The Company classifies its treasury bills as Level 1 assets under the fair value hierarchy, as these securities have been valued using quoted market prices for identical assets in active markets without any valuation adjustment. The Company classifies its commercial paper, corporate debt securities, and agency bonds as Level 2 assets under the fair value hierarchy, as these assets have been valued using quoted prices in active markets for similar securities.

4. Marketable securities

As of June 30, 2026 and December 31, 2025, the Company’s security portfolio consisted of 95 securities and 56 securities, respectively, related to marketable securities in debt securities available-for-sale, of which there were 88 securities and 10 securities in unrealized loss positions as of June 30, 2026 and December 31, 2025, respectively. There wereno securities in an unrealized loss position for greater than 12 months as of June 30, 2026 or December 31, 2025. The Company does not intend to sell the marketable securities prior to the value of the securities being recovered and it is not more likely than not that the Company will be required to sell the marketable securities before recovery of their amortized cost basis. The Company did not record an allowance for credit losses as of June 30, 2026 or December 31, 2025. Accrued interest receivable relating to the Company’s available-for-sale securities is presented within prepaid expenses and other current assets in the accompanying condensed consolidated balance sheets, and amounted to $2.3 million and $1.1 million as of June 30, 2026 and December 31, 2025, respectively.

Marketable securities, which are classified as available-for-sale, consisted of the following (in thousands):

5. Property and equipment, net

Property and equipment consisted of the following (in thousands):

The Company recorded depreciation expense of $0.9 million and $0.6 million for the three months ended June 30, 2026 and 2025, respectively. The Company recorded depreciation expense of $1.5 million and$1.0 million for the six months ended June 30, 2026 and 2025, respectively.

6. Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):

7. Stockholders’ deficit

Common stock and Class A common stock

Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders provided, however, that, except as otherwise required by law, holders of common stock are not entitled to vote on any amendment to the Company’s Certificate of Incorporation that relates solely to the terms of one or more outstanding series of Class A common stock or preferred stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to the Certificate of Incorporation or pursuant to the Delaware General Corporation Law. Each share of Class A common stock is non-voting. There is no cumulative voting. Both common stockholders and Class A common stockholders are entitled to receive dividends, as may be declared by the Company’s Board, if any. Through June 30, 2026, no dividends have been declared or paid.

The Company’s common stock available for future issuance is summarized below:

8. Equity-based compensation

2020 Equity Incentive Plan

The Company’s 2020 Equity Incentive Plan, as amended (the “2020 Plan”), provided for the Company to sell or issue common stock or restricted common stock, and other awards, as determined by the Board, to employees, non-employees and directors of the Company. As of the effective date of the 2026 Equity Incentive Plan (the “2026 Plan”), and as of June 30, 2026, there wereno shares remaining available for future issuance under the 2020 Plan. Any options or other awards outstanding under the 2020 Plan remain outstanding and effective.

2026 Equity Incentive Plan

In January 2026, the Board and the Company's stockholders adopted and approved the 2026 Plan, which became effective on January 8, 2026. The 2026 Plan initially reserved 4,009,452 shares of common stock for future issuances and is subject to automatic increases in the number of shares of common stock reserved for future issuances in accordance with the evergreen provisions in the 2026 Plan. Any shares underlying outstanding stock awards granted under the 2020 Plan that subsequently expire or are repurchased, forfeited, cancelled, or withheld will return to the 2026 Plan and be reserved and available for issuance. As of June 30, 2026, there were 2,155,904 shares remaining available for future issuance under the 2026 Plan.

2026 Employee Stock Purchase Plan

In January 2026, the Board and the Company's stockholders adopted and approved the 2026 Employee Stock Purchase Plan (the "2026 ESPP"), which became effective on January 8, 2026. The 2026 ESPP initially reserved 27,843 shares of common stock for future issuance and is subject to automatic increases in the number of shares of common stock reserved for future issuances in accordance with the evergreen provisions in the 2026 ESPP. As of June 30, 2026, there were 27,843 shares remaining available for future issuance under the 2026 ESPP.

Stock Option Activity

The following table summarizes the stock option activity during the six months ended June 30, 2026:

Compensation cost is recognized on a straight-line basis over the requisite service period. As of June 30, 2026, the total unrecognized compensation cost related to unvested stock option awards was $35.0 million which the Company expects to recognize over a weighted-average period of approximately 2.72 years.

The weighted-average grant date fair value per share of stock options granted during the six months ended June 30, 2026 and 2025 was $13.86 and $2.06, respectively. The total intrinsic value of stock options exercised during the six months ended June 30, 2026 and 2025 was $0.8 million and $0.2 million, respectively.

The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of the stock options granted during the periods ended:

Stock-based compensation expense

The following table summarizes stock-based compensation expense included in operating expenses (in thousands):

9. Income taxes

The Company did not record a provision or benefit for income taxes during the three and six months ended June 30, 2026 and 2025. The Company continues to maintain a full valuation allowance against its U.S. federal and state deferred tax assets as it is more likely than not that such assets will not be realized in the future.

As of June 30, 2026 and December 31, 2025, the Company hadno uncertain tax positions relevant to the jurisdictions where it is required to file income tax returns requiring recognition in the consolidated financial statements. As of June 30, 2026 and December 31, 2025, the Company hadno accrued interest or penalties related to uncertain tax positions.

10. License agreements

The Company has entered into several license agreements with third parties that typically involve payments from the Company, including upfront payments, milestone payments and royalty payments. The terms and conditions as well as accounting analysis for the Company’s significant license agreements are described in Note 11, “License agreements” in the audited consolidated annual financial statements for the years ended December 31, 2025. As of June 30, 2026, no milestones have been achieved under these agreements. There have been no other material changes to the terms and conditions or accounting conclusions previously disclosed in the Annual Report.

11. Collaboration revenue

Eli Lilly collaboration agreement

In May 2024, the Company entered into the Collaboration Agreement with Eli Lilly and Company ("Eli Lilly") to generate anticancer radiopharmaceuticals using the Company's novel miniprotein technology platform. The terms and conditions as well as accounting analysis for the Company’s Collaboration Agreement are described in Note 12, “Collaboration revenue” in the audited consolidated annual financial statements for the year ended December 31, 2025.

The Company recognized $3.4 million and $6.6 million of collaboration revenue during the three and six months ended June 30, 2026, respectively. The Company recognized $1.6 million and $3.0 million of collaboration revenue during the three and six months ended June 30, 2025. The remaining transaction price of $48.2 million is expected to be recognized as revenue through 2030. As of June 30, 2026, one development milestone under the Collaboration Agreement totaling $1.0 million had been achieved. There have been no other material changes to the terms and conditions or accounting conclusions previously disclosed in the Annual Report.

12. Commitments and contingencies

Legal proceedings

The Company was not subject to any material legal proceedings during the six months ended June 30, 2026 and 2025, and the Company is not aware of any material legal proceedings that are currently pending or threatened.

Royalty transfer agreement

On August 27, 2020, the Company entered into a royalty transfer agreement (the "Royalty Transfer Agreement") with MPM Oncology Charitable Foundation, Inc. (the “MPM Charitable Foundation”), an affiliate of a stockholder holding more than 5% of the total outstanding stock of the Company, and the UBS Optimus Foundation (“UBS" and together with MPM Charitable Foundation, the “Charitable Foundations”). Pursuant to the Royalty Transfer Agreement, the Company will pay 0.5% of annual global net sales to each of the Charitable Foundations, for a total of 1.0% of net sales, subject to customary reductions, for products that incorporate or utilize intellectual property that was discovered or developed by the Company prior to an initial public offering. The Company's payment obligations for each product will continue on a country-by-country basis upon the later of the twelfth anniversary of the first commercial sale of such product in such country or the expiration of the last to expire of certain patents owned or controlled by the Company covering such products in such country.

The Company’s payment obligations to MPM Charitable Foundation will terminate immediately upon authorization of the MPM Charitable Foundation's board of directors (or similar body) or upon the winding up or dissolution of MPM Charitable Foundation. The Company’s payment obligations to UBS will terminate immediately upon the winding up of Oncology Impact Fund 2, L.P., a Cayman Islands exempt limited partnership which is affiliated with MPM Charitable Foundation.

The Company will record a liability when the associated net sales are generated.

13. Leases

Operating leases

In March 2021, the Company entered into a lease agreement for a research and development laboratory and related office space located in Durham, North Carolina (the "Durham Lease"). The Durham Lease was extended with a revised termination date of September 30, 2027. The Durham Lease extension was accounted for as a modification in accordance with ASC 842 and the Company reassessed the lease liability andright-of-use (“ROU”) asset related to the lease. The extension resulted in an increase of $0.4 million to the related operating lease ROU asset and lease liability.

In January 2022, the Company entered into a lease for office, laboratory and storage space located in Boston, Massachusetts. The lease is set to expire 10 years from the rent commencement date of January 4, 2023.

14. Net loss per share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows for the periods presented (in thousands, except share and per share amounts):

The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common stock outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same.

As the liquidation and dividend rights are identical for the Company's common stock and Class A common stock, the undistributed earnings are allocated on a proportionate basis and the resulting amount per share for the Company's common stock and Class A common stock was the same for the three and six months ended June 30, 2026. The Company only had one class of common stock outstanding as of June 30, 2025.

The following outstanding potentially dilutive securities have been excluded from the computation of diluted net loss per share attributable to common stockholders, as including them would have had an anti-dilutive effect:

15. Segment information

The Company hasone operating and reportable segment focused on the research and development of targeted radiopharmaceuticals to treat a broad range of solid tumor cancers. The accounting policies of the single operating segment are identical to those described in Note 2, “Summary of significant accounting policies,” in the audited consolidated annual financial statements for the year ended December 31, 2025.

The chief operating decision-maker (“CODM”) manages the Company’s operations on a consolidated basis and assesses performance based on consolidated net loss, which is reported on the condensed consolidated statements of operations. The measure of segment assets is reported on the condensed consolidated balance sheets as total consolidated assets. Expenditures for additions to long-lived assets, which include purchases of property and equipment, are included in total consolidated assets reviewed by the CODM and are reported on the condensed consolidated statements of cash flows. The CODM uses consolidated net loss and budget-to-actual variances to allocate resources and assess the performance of the company.

Certain segment information for prior periods has been recast to conform to the current period presentation. The recast did not impact the Company's previously reported consolidated results of operations.

The following information represents significant segment expenses regularly provided to the CODM with the following categories (in thousands):

Information technology, facilities, office and other includes depreciation and amortization.

Other segment items consist of interest income and other expense, net. Interest income consists of interest earned on cash equivalents and marketable securities and amortization or accretion of discounts or premiums on marketable securities. Other expense, net consists of gains and losses on currency revaluation related to the payment of foreign vendor invoices.