Boundless Bio, Inc.

Organization and Basis of Presentation

Description of Business

Boundless Bio, Inc. (the Company) is a clinical-stage oncology company dedicated to unlocking a new paradigm in cancer therapeutics that addresses the significant unmet need in patients with oncogene amplified tumors by interrogating extrachromosomal DNA (ecDNA), a root cause of oncogene amplification observed in 14 to 17% of cancer patients. The Company has been focused on identifying targets essential for ecDNA functionality in oncogene amplified cancer cells, then designing and developing small molecule drugs called ecDNA-directed therapeutic candidates (ecDTx) to inhibit those targets, with the aim to prevent cancer cells from using chromosomal instability and ecDNA amplification biology to grow, adapt, and become resistant to existing therapies. The Company’s mission is to be the foremost biopharma company interrogating ecDNA biology to deliver transformative therapies that improve and extend the lives of patients with previously intractable oncogene amplified cancers. The Company’s lead ecDTx, BBI-940, is in early clinical development in patients with estrogen receptor positive and human epidermal growth factor receptor 2 negative, or ER+/HER2-, breast cancer who have progressed following treatment with a cyclin-dependent kinase 4 and/or 6 inhibitor, or CDK4/6 inhibitor, plus endocrine therapy, as well as patients with triple-negative breast cancer luminal androgen receptor subtype, or TNBC-LAR. The Company was incorporated in the state of Delaware on April 10, 2018 and is headquartered in San Diego, California.

Initial Public Offering

On April 2, 2024, the Company completed its initial public offering (IPO), issuing 6,250,000 shares of its common stock at a public offering price of $16.00 per share, resulting in net proceeds of approximately $87.7 million, after deducting underwriting discounts, commissions, and other offering expenses. Immediately prior to the closing of the IPO, all outstanding shares of convertible preferred stock of the Company automatically converted into 14,740,840 shares of its common stock, and no shares of convertible preferred stock remained outstanding thereafter. In connection with the closing of the IPO, on April 2, 2024, the Company amended and restated its certificate of incorporation to authorize 700,000,000 shares of common stock and 70,000,000 shares of undesignated preferred stock, each with a par value of $0.0001 per share.

ATM Offering

On April 1, 2025, the Company entered into an Open Market Sale Agreement SM (the Sales Agreement) with Jefferies LLC (the Agent), under which the Company may, from time to time, sell shares of the Company’s common stock in “at the market” (ATM) offerings through or to the Agent, as sales agent or principal. The shares of common stock will be offered and issued pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-286302), including the Sales Agreement prospectus contained therein, filed with the Securities and Exchange Commission (SEC) on April 1, 2025 and declared effective by the SEC on April 10, 2025. Pursuant to the Sales Agreement prospectus, the Company may sell shares of its common stock having an aggregate offering price of up to $14.5 million. Sales of the shares of common stock, if any, will be made at prevailing market prices at the time of sale, or as otherwise agreed with the Agent. The Agent will receive a commission from the Company of up to 3.0% of the gross proceeds of any shares of common stock sold under the Sale Agreement. The Company is not obligated to sell, and the Agent is not obligated to buy or sell, any shares of common stock under the Sales Agreement. No assurance can be given that the Company will sell any shares of common stock under the Sales Agreement, or, if it does, as to the price or amount of shares of common stock that it sells or the dates when such sales will take place. The Company didnot sell any shares under the Sales Agreement during the year ended December 31, 2025.

Liquidity

Since the Company commenced operations in 2018, it has devoted substantially all of its efforts and resources to organizing and staffing the Company, business planning, raising capital, building its proprietary Spyglass platform, discovering its ecDTx, developing its ecDNA diagnostic, establishing its intellectual property portfolio, conducting research, preclinical studies, and clinical trials, establishing arrangements with third parties for the manufacture of its ecDTx and related raw materials, and providing other general and administrative support for these operations. The Company does not have any products for sale and has not generated any revenue to date. The Company has funded its operations primarily from the sale and issuance of shares of its convertible preferred stock (prior to the IPO) and common stock.

As of December 31, 2025, the Company had cash, cash equivalents, and short-term investments of $107.6 million. The Company believes that its existing cash, cash equivalents, and short-term investments will be sufficient to fund its operations for at least twelve months from the issuance date of the accompanying financial statements.

Since inception, the Company has incurred significant operating losses and negative cash flows from its operations and expects that it will continue to do so into the foreseeable future as it continues its development of, seeks regulatory approval for, and potentially commercializes its ecDTx, utilizes third parties to manufacture its ecDTx and related raw materials, potentially identifies additional development opportunities for its ecDTx, seeks to expand its therapeutic pipeline, and expands and protects its intellectual property. The Company also has substantial payment obligations under a long-term non-cancellable facility lease. If the Company obtains regulatory approval for any of its ecDTx, it expects to incur significant commercialization expenses related to product sales, marketing, manufacturing, and distribution. The Company does not expect to generate any revenue from product sales until it successfully completes development of and obtains regulatory approval for one or more of its ecDTx, which the Company expects will take several years and may never occur. As of December 31, 2025, the Company had an accumulated deficit of $259.7 million, and, during the year ended December 31, 2025, the Company incurred a net loss of $58.2 million and had negative cash flows from operations of $46.7 million. As the Company continues to pursue its business plan, it will need to acquire a substantial amount of additional funding until such time as it is able to generate significant revenues to fund its research and development activities and operations. Accordingly, the Company expects to finance its cash requirements through equity offerings, debt financings, or other capital sources, including potential collaborations, licenses, and other similar arrangements. There can be no assurance that the Company will be successful in acquiring additional funding or that any additional funding would be sufficient to continue operations in future periods.

Basis of Presentation

The accompanying financial statements are presented in U.S. dollars and have been prepared in accordance with United States generally accepted accounting principles (U.S. GAAP). Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB).

Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenue and expenses, and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may materially differ from these estimates and assumptions.

On an ongoing basis, management evaluates its estimates, primarily related to stock-based compensation, the fair value of its investments, accrued research and development costs and, prior to the closing of its IPO, its common stock. These estimates are based on historical data and experience, as well as various other factors that management believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. The Company’s estimates relating to stock-based compensation expense require the selection of appropriate valuation methodologies and models, and significant judgment in evaluating ranges of assumptions and financial inputs.

Cash, Cash Equivalents, and Restricted Cash

The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts.

The balance reflected in these financial statements as restricted cash represents a deposit account pledged as collateral to secure a standby letter of credit required as a security deposit under the Company’s headquarters facility lease. The Company has classified the restricted cash as a noncurrent asset on its balance sheets as of December 31, 2025 and 2024.

Concentration of Credit Risk

Financial instruments, which potentially subject the Company to the concentration of credit risk, consist primarily of cash, cash equivalents, and investments. The Company maintains deposits in federally insured financial institutions which exceeded federally insured limits by $1.4 million as of December 31, 2025. Management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes its exposure to concentration of credit risk.

Short-Term Investments

Short-term investments consist of money market funds, U.S. government obligations, corporate debt securities, government agency securities, asset-backed securities, and commercial paper. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bid and/or offers. The Company classifies its investment securities as available-for-sale, as the sale of such securities may be required prior to maturity. Management determines the appropriate classification of its investments in debt securities at the time of purchase. Investments with original maturities beyond three months at the date of purchase and which mature at, or less than 12 months from, the balance sheet date are classified as short-term investments. Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported as accumulated other comprehensive income (loss) until realized. The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.

At each balance sheet date, the Company reviews its available-for-sale debt securities that are in an unrealized loss position to determine whether the unrealized loss or any potential credit losses should be recognized in the statements of operations. For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell, the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through net income (loss). For available-for-sale securities that do not meet the above criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, the Company considers the severity of the impairment, any changes in interest rates, changes to the underlying credit ratings and forecasted recovery, among other factors. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded in other income, net through an allowance account. There have beenno impairment or credit losses recognized during any of the periods presented.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under US GAAP. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement determined based on assumptions that market participants would use in pricing an asset or liability. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

Level 1—Quoted prices in active markets for identical assets or liabilities.

Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies, and similar techniques.

Cash, cash equivalents, and short-term investments are carried at fair value, determined according to the fair value hierarchy described above. The carrying values of the Company’s prepaid expenses, accounts payable, and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis.

Deferred Offering Costs and Common Stock Issuance Costs

The Company capitalizes certain legal, professional, accounting, and other third-party costs that are directly attributable to equity financings as deferred offering costs until such financings are consummated. Upon consummation of an equity financing, these costs are recorded as a reduction to additional paid-in capital within stockholders’ equity. In connection with the closing of the Company’s IPO in April 2024, all amounts previously recorded as deferred offering costs were reclassified to additional paid-in capital.

Property and Equipment, Net

Propertyand equipment, including leasehold improvements, are stated at cost less accumulated depreciation and amortization. Depreciation and amortization are recorded using the straight-line method over the estimated useful lives of the related assets, which range from three to seven years. Leasehold improvements are amortized on a straight-line basis over the shorter of the estimated useful livesof the assets or the remaining lease term. Repairs and maintenance charges that do not increase the useful life of the assets are charged to operating expenses as incurred.

Impairment of Long-Lived Assets

An impairment loss is recorded if and when events and circumstances indicate that any of the Company’s long-lived assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book values of the assets exceed their fair value. The Company has not recognized any impairment losses in any of the periods presented in these financial statements.

Leases

At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease and whether such a lease should be classified as a financing lease or operating lease based on the unique facts and circumstances present, the existence of an identified asset(s), if any, and the Company’s control over the use of the identified asset(s), if applicable. In 2025 and 2024, the Company leased real estate facilities under non-cancellable operating leases with various expiration dates through fiscal year 2034. As of December 31, 2025, the Company had one operating lease, which expires in 2034. As of December 31, 2025 and 2024, the Company had no financing leases.

Operating leases with a term greater than one year are recognized as right-of-use (ROU) assets and lease liabilities in the accompanying balance sheets. Operating lease ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The Company considers the lease term to be the non-cancellable period that it has the right to use the underlying asset, together with any periods where it is reasonably certain it will exercise an option to extend (or not terminate) the lease. The Company does not assume renewals or early terminations unless it is reasonably certain to exercise these options.

Operating lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term discounted based on (i) the interest rate implicit in the lease if that rate is readily determinable, or if not, (ii) the Company’s incremental borrowing rate (which is the estimated interest rate the Company would be required to pay for a collateralized borrowing equal to the total lease payments over a similar term as the lease term and in a similar economic environment). Because the Company’s operating leases do not provide an implicit rate, the Company estimates its incremental borrowing rate based on the information available at the lease commencement date for borrowings with a similar term. The Company’s operating lease ROU assets are measured based on the corresponding operating lease liability adjusted for (i) payments made to the lessor at or before the commencement date, (ii) initial direct costs incurred and (iii) tenant incentives under the lease.

Operating lease costs are recognized on a straight-line basis over the lease term. The Company elected not to allocate consideration between lease and non-lease components. Variable lease payments are recognized in the period in which the obligations for those payments are incurred. In addition, the Company elected not to recognize lease assets or lease liabilities for leases with a term of 12 months or less for all asset classes.

Segment Reporting

Operating segments are identified as components of an enterprise about which discrete financial information is available for evaluation by the chief operating decision-maker (CODM) in making decisions regarding resource allocation and assessing performance. The Company operates and manages its business asone reporting andone operating segment, which is the business of designing and developing ecDTx, for which no revenue has been recorded. All of the Company’s long-lived assets are located in the United States. The Company’s CODM is its Chief Executive Officer. For purposes of assessing the Company’s financial performance and making resource allocation decisions, the CODM reviews total expenses, as well as expenses by nature.

Convertible Preferred Stock

The Company’s convertible preferred stock was classified as temporary equity in the accompanying balance sheet as of December 31, 2023 and excluded from stockholders’ equity/ (deficit) as the potential redemption of such stock was outside the Company’s control and would have required the redemption of the then-outstanding convertible preferred stock. The convertible preferred stock was not redeemable except for in the event of a liquidation, dissolution, or winding up of the Company. Costs incurred in connection with the issuance of convertible preferred stock were recorded as a reduction of gross proceeds from issuance. The

Company did not accrete the carrying values of the convertible preferred stock to the redemption values since the occurrence of these events was not considered probable as of December 31, 2023. Immediately prior to the closing of the IPO on April 2, 2024, the Company’s outstanding convertible preferred stock automatically converted into 14,740,840 shares of common stock. Following the closing of the IPO, no shares of convertible preferred stock were authorized or outstanding.

Research and Development Expenses

Research and development (R&D) expenses are costs incurred by the Company in connection with its discovery and research efforts and the preclinical and clinical development of ecDTx. The Company’s R&D expenses include direct program costs, consisting of expenses incurred under arrangements with third parties, such as contract research organizations, contract manufacturers, consultants and its scientific advisors; and indirect costs, consisting of personnel-related expenses, including salaries, severance, bonuses, benefits, travel, and stock-based compensation expenses, for those individuals involved in R&D efforts, the costs of lab and pharmacology supplies and acquiring, developing, and manufacturing preclinical and clinical study materials, and facilities and depreciation, which include direct and allocated expenses for rent of facilities and depreciation of equipment. R&D costs are expensed as incurred.

The Company records accruals for estimated R&D costs, comprising payments for work performed by third party contractors, labs, and others. Some of these contractors bill monthly based on actual services performed, while others bill periodically based upon achieving certain contractual milestones. For the latter, the Company accrues the expenses as goods or services are used or rendered. Non-refundable advance payments for goods or services that will be used or rendered for future R&D activities are deferred and capitalized as prepaid expenses until the related goods are delivered or services are performed.

General and Administrative Expenses

General and administrative (G&A) expenses consist primarily of personnel-related expenses, including salaries, severance, bonuses, benefits, travel, and stock-based compensation expenses, for employees in executive, accounting and finance, business development, human resources, legal, and other administrative functions. Other significant G&A expenses include allocated facility-related costs, legal fees relating to corporate and intellectual property matters, professional fees for accounting and tax services, consulting fees, and insurance costs. G&A costs are expensed as incurred.

Costs related to filing and pursuing patent applications are recorded as G&A expense and are expensed as incurred since the recoverability of such expenditures is uncertain.

Stock-Based Compensation

The Company measures employee and nonemployee stock-based awards based on the estimated fair value of the awards on the date of grant and records compensation expense on a straight-line basis over the requisite service period of the award. All stock-based compensation costs are recorded in the statements of operations and comprehensive loss based upon the underlying employees' or nonemployees' roles within the Company. Forfeitures are accounted for as they occur.

The fair value of stock option grants and shares purchasable under the Company's 2024 Employee Stock Purchase Plan (ESPP) is estimated on the date of grant using the Black-Scholes options-pricing model, which requires inputs based on certain subjective assumptions, including the:

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Fair value of common stock. Subsequent to the closing of the IPO, the fair value of the Company’s common stock is the closing price per share on the Nasdaq Global Select Market on the date of grant of the award. For periods prior to the closing of the IPO on April 2, 2024, the Company utilized methodologies, approaches, and assumptions consistent with the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately Held Company Equity Securities Issued as Compensation (The Practice Aid) to estimate the fair value of its common stock. The fair value of the common stock was determined based upon a variety of factors, including the Company’s stage of development and material risks related to the business; the progress of the Company’s R&D programs; business conditions and projections; financial position and historical and forecasted performance and operating results; the lack of an active public market for the Company’s common stock and preferred stock; the prices of the Company’s preferred stock sold to or exchanged between outside investors in arm’s length transactions and the rights, preferences, and privileges of the preferred stock as compared to those of the Company’s common stock, including liquidation preferences of the Company’s preferred stock; the likelihood of achieving a liquidity event, such as an initial public offering or sale of the Company in light of prevailing market conditions; the hiring of key personnel and the experience of management; trends and developments in the

Company’s industry; and external market conditions affecting the biopharmaceutical industry and trends within the biopharmaceutical industry.

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Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to the expected term of the award being valued.

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Expected volatility. Given that there was no active trading market for the Company’s common stock prior to the completion of the IPO and there is not yet sufficient trading history for the Company’s common stock, the Company derived the expected volatility from the average historical volatilities of the common stock of a group of comparable publicly-traded companies in the biotechnology industry over a period approximately equal to the expected term of the award being valued. The Company will continue to apply this process until enough historical information regarding the volatility of its own stock price becomes available.

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Expected term. The expected term represents the period that the stock-based awards are expected to be outstanding. The expected term of stock options issued is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term) as the Company has concluded that its stock option exercise history does not provide a reasonable basis upon which to estimate expected term. For rights to purchase shares of common stock under the ESPP, the expected term represents the period from the first day of the offering period to the purchase date.

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Expected dividend yield. The Company has never paid dividends on its common stock and does not anticipate paying any dividends in the foreseeable future. Therefore, the Company uses an expected dividend yield of zero.

The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date.

The assumptions used in determining the estimated fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of significant judgment.

The Company reviews all stock-based award modifications, including situations in which an original award is exchanged for a new award. Stock award modifications are accounted for as modifications under ASC 718. In such cases, the Company measures incremental compensation cost as the excess of the fair value of the modified award over the fair value of the original award immediately prior to the modification, based on the relevant factors at the modification date.

For vested awards, the Company recognizes any incremental compensation cost in the period in which the modification occurs. For unvested awards, if the modified award is probable of vesting both before and after the modification, the Company recognizes, on a prospective basis over the remaining requisite service period, the sum of (i) the incremental compensation cost and (ii) any remaining unrecognized compensation cost associated with the original award as of the modification date. If the fair value of the modified award is lower than the fair value of the original award immediately before the modification, the Company continues to recognize compensation cost at least equal to the cost of the original award.

During 2025, the Company entered into consulting arrangements with several former employees that provided for the continued vesting of outstanding stock options. The Company accounted for these arrangements as award modifications under ASC 718. Results of operations for the year ended December 31, 2025 include an immaterial amount of additional stock-based compensation expense associated with these modifications.

Income Taxes

The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s financial statements and related disclosures. Deferred tax assets and liabilities are determined on the basis of the differences between the Company’s financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including projected future taxable income, future reversals of existing taxable temporary differences, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Interest and penalties are included as a component of income tax expense.

The Company records uncertain tax positions on the basis of a two-step process whereby (i) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (ii) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. Any resulting unrecognized tax benefits are included within the related tax liability.

In July 2025, legislation commonly referred to as the One Big Beautiful Bill Act (OBBBA) was enacted, which includes changes to U.S. tax law, including provisions affecting the deductibility of domestic research expenditures, limitations on interest expense deductions, and bonus depreciation. The Company evaluated the impact of the enacted legislation under ASC 740. Any remeasurement of deferred tax assets resulting from the legislation was fully offset by the Company’s existing valuation allowance. Accordingly, the enactment of the OBBBA did not have a material impact on the Company’s financial statements.

Comprehensive income (loss)

The Company reports all components of comprehensive income (loss), including net loss, in the financial statements in the period in which they are recognized. Comprehensive income (loss) is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on short-term investments. Other comprehensive income (loss) includes unrealized gains and losses on short-term investments, which was the only difference between net loss and comprehensive loss for the applicable periods.

Net Loss Per Share

Basic net loss per common share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is calculated by dividing the net loss by the weighted-average number of shares of common stock and potentially dilutive securities outstanding during the period. The Company’s potentially dilutive securities, which include its options to purchase common stock, common stock subject to repurchase related to unvested restricted stock and options early exercised, and, for periods prior to April 2, 2024, convertible preferred stock, have been excluded from the calculation of diluted net loss per share as the effect would reduce the net loss per share. Therefore, the weighted-average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same.

Emerging Growth Company Status

The Company is still an emerging growth company (EGC) as defined in the Jumpstart Our Business Startups Act of 2012, as amended (the JOBS Act), and may take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not EGCs. The Company may take advantage of these exemptions until it is no longer an EGC under Section 107 of the JOBS Act and has elected to use the extended transition period for complying with new or revised accounting standards, which means that when an accounting standard is issued or revised and it has different effective dates for public and private companies, the Company can comply with the effective dates applicable to private companies. As a result, the Company’s financial statements may not be comparable to companies that comply with new or revised accounting standards as of public company effective dates.

Recently Adopted Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures. The update enhances income tax disclosure requirements, including expanded information related to the effective tax rate reconciliation and income taxes paid, and does not affect the recognition or measurement of income taxes. The Company adopted this guidance effective January 1, 2025 and applied the new disclosure requirements prospectively for the year ended December 31, 2025. The adoptiondid not materially affect the Company’s financial statements, and the additional required disclosures are included in Note 11.

Recently Issued Accounting Pronouncements Pending Adoption

In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (ASU 2024-03). The new guidance requires more detailed information about specified types of expenses (including purchases of inventory, employee compensation, depreciation, amortization, and depletion) in commonly presented expense captions (such as R&D and G&A) presented on the face of the statement of operations on an annual and interim basis. This guidance will be effective for annual periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027. The new standard permits early adoption and can be applied prospectively or retrospectively. The Company is evaluating the effect that this guidance will have on its financial statements and related disclosures.

Fair Value Measurements

The following tables summarize the Company’s financial assets measured at fair value on a recurring basis and their respective input levels based on the fair value hierarchy described in Note 2 above (in thousands):

(1)

Included in cash and cash equivalents on the balance sheets.

(2)

Included in short-term investments on the balance sheets.

(1)

Included in cash and cash equivalents on the balance sheets.

(2)

Included in short-term investments on the balance sheets.

The Company’s money market funds are classified as Level 1 because they are valued using quoted market prices in active markets for identical assets. The Company’s investments consist of available-for-sale securities and are classified as Level 2 because their value is based on valuations using significant inputs derived from or corroborated by observable market data.

There wereno transfers of assets between fair value levels for any period presented.

Investments

The following tables summarize investments accounted for as available-for-sale securities (in thousands):

On December 31, 2025 and 2024, the remaining contractual maturities of all the Company’s available-for-sale investments were less than twelve months. As of December 31, 2025 and 2024, the Company has not established an allowance for credit losses for any of its available-for-sale securities.

As of December 31, 2025, there wereno available-for-sale securities in a gross unrealized loss position. As of December 31, 2024, there wasone available-for-sale security, with an estimated fair value of $8.0 million, in a gross unrealized loss position. Based on its review of these investments as of December 31, 2025 and 2024, the Company believed that the unrealized loss as of December 31, 2024 was not other-than-temporary in nature.

Property and Equipment

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

Depreciation and amortization expense related to property and equipment was $1.3 million and $1.1 million for the years ended December 31, 2025 and 2024, respectively.

Accounts Payable and Accrued Liabilities

Accounts payable and accrued liabilities consisted of the following (in thousands):

Lease Agreements

2024 Lease

The Company is a party to a non-cancellable facility lease for approximately 80,168 square feet of lab and office space in San Diego, California (the 2024 Lease). The 2024 Lease has an initial lease term of 120 months, which commenced in November 2024; the lease also provides the Company with the right to extend the lease term for an additional 60 months at expiry, which has not been included in the lease term used for measurement. The 2024 Lease includes obligations to make base rent payments and additional variable lease payments for the Company’s allocated share of variable costs associated with the operation and management of the property, which include utilities, property taxes, common area maintenance, and amenities costs. The lease provided for a rent abatement period through July 2025.

The Company is required to maintain a security deposit under the 2024 Lease in the form of a standby letter-of-credit. This letter of credit is collateralized by a restricted cash deposit at the Company’s bank of approximately $0.6 million, which is included in long-term other assets in the balance sheet. The 2024 Lease does not contain any material residual value guarantees or material restrictive financial covenants. See the table below for information about the Company’s future undiscounted operating lease payment obligations under the 2024 Lease as of December 31, 2025, exclusive of future variable lease costs.

The Company recorded an operating lease liability for this obligation based on the present value of the lease payments using an estimated incremental borrowing rate of approximately 8.3%, as the 2024 Lease does not have a stated rate and the implicit rate was not readily determinable, and a right-of-use (ROU) asset based on the corresponding operating lease liability. Management exercised judgment in estimating the incremental borrowing rate and in determining the lease term. The renewal option was evaluated at lease commencement and excluded from the lease term, as the Company is not reasonably certain to exercise the option. The net ROU asset and associated lease liability are reflected in the Company’s balance sheet as of December 31, 2025 and 2024.

Operating leases

As of December 31, 2025, the 2024 Lease, which expires in October 2034, was the Company’s only lease. The Company previously was a party to a non-cancellable operating lease for the rental of other lab and office space in San Diego, California, which served as its prior corporate headquarters and for which the lease term ended in November 2024. Lease expense related to the 2024 Lease and the lease agreement for the Company’s prior corporate headquarters totaled approximately $9.6 million and $4.0 million for the years ended December 31, 2025 and 2024, respectively, and included operating lease costs of $7.3 million and $3.6 million, and variable lease costs of $2.3 million and $0.4 million, respectively.

The Company paid $2.6 million in cash for amounts included in operating lease liabilities, which was included in the operating activities section of the statements of cash flows, for each of the years ended December 31, 2025 and 2024. The remaining lease term and discount rate for the 2024 Lease were 8.8 years and 8.3%, respectively, as of December 31, 2025, and 9.8 years and 8.3%, respectively, as of December 31, 2024 (the calculations of remaining lease term excludes the renewal option). Future undiscounted operating lease payments under the 2024 Lease as of December 31, 2025, exclusive of future variable lease payments, are as follows (in thousands):

Commitments and Contingencies

Contracts

The Company enters into contracts in the normal course of business with various third parties for preclinical research studies, clinical trials, testing, manufacturing, and other services. These contracts generally provide for termination upon notice and are cancellable without significant penalty or payment, other than payment for any products or services provided by the counterparty through the notice date or effective time of termination and any non-cancellable and non-refundable obligations incurred by the counterparty prior to the notice date or effective time of the termination, and do not contain any minimum purchase commitments.

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners, and other parties with respect to certain matters including, but not limited to, losses arising out of breach of agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with officers and members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise because of their status or service as officers or directors. The maximum potential future payments the Company could be required to make under these indemnification arrangements is, in many cases, unlimited. To date, the Company has not incurred any material costs because of these indemnifications. The Company has not accrued any liabilities related to such indemnification arrangements in its financial statements as of December 31, 2025 or 2024 because it determined the likelihood of incurring a payment obligation pursuant to such arrangements was not probable.

Litigation

Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties, and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. There are no matters currently outstanding for which any liabilities have been accrued. The Company was not a defendant in any lawsuit for the years ended December 31, 2025 and 2024.

Common Stock

Common Stock Rights

The holder of each outstanding share of common stock is entitled toone vote on all matters submitted to a vote of the holders of common stock. Subject to the rights of the holders of any class of the Company’s capital stock having any preference or priority over common stock, the holders of common stock are entitled to receive dividends that are declared by the Company’s board of directors out of legally available funds. In the event of a liquidation, dissolution or winding-up, the holders of common stock are entitled to share ratably in the net assets remaining after payment of liabilities and the liquidation value of any class of the Company’s capital stock having any preference or priority over the common stock then outstanding, if any. The common stock has no preemptive rights, conversion rights, redemption rights, preference rights, or exchange rights, or sinking fund provisions, and there are no dividends in arrears or default. All shares of common stock have equal distribution, liquidation and voting rights.

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following (in thousands):

Stock-Based Compensation

Equity Incentive Plan

In March 2024, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2024 Incentive Award Plan (the Plan), which became effective in connection with the IPO and has a term often years. The Plan provides for the grant of incentive stock options, nonqualified stock options, restricted stock, dividend equivalents, restricted stock units, stock appreciation rights, and other stock or cash-based awards to the Company's employees, consultants, and directors. Options granted under the Plan are exercisable at various dates as determined upon grant and will expire no more than 10 years from their date of grant. Stock options generally vest over terms of either 36 or 48 months. The exercise price of awards granted under the Plan shall not be less than 100% of the fair market value of the Company’s common stock on the date of grant. In addition, the Plan includes an “evergreen” provision whereby the number of shares of common stock available for issuance under the Plan will be increased annually on the first day of each calendar year during the term of the Plan, beginning in 2025, by an amount equal to the lesser of (i)5% of the shares of common stock outstanding on the final day of the immediately preceding calendar year or (ii) such number of shares as determined by the Company’s board of directors or an authorized committee of the board of directors. As of December 31, 2025, a total of 3,947,716 sharesof common stock were authorized for issuance under the Plan. On December 31, 2025,3,347,667 of these shares were available for grant under the Plan. On January 1, 2026, pursuant to the evergreen provision of the Plan, the aggregate number of shares that may be issued under the Plan was automatically increased by 1,120,362 shares to 5,068,078.

Prior to the adoption of the Plan, the Company had awarded common stock options under the 2018 Equity Incentive Plan (as amended, the Predecessor Plan). Under the provisions of the Plan, the shares subject to awards issued under the Predecessor Plan that were outstanding as of March 27, 2024, the effective date of the Plan, and that are subsequently cancelled or forfeited, will become available for issuance under, and will increase the number of shares that may be issued under, the Plan.

Repricing of Outstanding Options

In August 2024, the compensation committee of the Company’s board of directors, as administrator of the Plan and the Predecessor Plan, approved an option repricing (2024 Repricing), which was effective on August 19, 2024 (the Repricing Effective Date). The repricing applied to options to purchase up to an aggregate of 3,484,346 shares of the Company’s common stock with an exercise price per share in excess of the closing price per share of the Company’s common stock on the Repricing Effective Date, held by eligible employees of the Company that were granted under the Plan or the Predecessor Plan and were outstanding as of the Repricing Effective Date (the Repriced Options). As of the Repricing Effective Date, the exercise price of each of the Repriced Options was reduced to $3.56 per share, which was the closing price of the Company’s common stock on the Repricing Effective Date; provided, however, that if prior to the Premium End Date (as defined below), a Repriced Option is exercised or an employee’s employment or service with the Company terminates for any reason other than due to a Qualifying Termination (as defined below), the exercise price per share that applied to the Repriced Option immediately prior to the Repricing Effective Date will apply in lieu of the reduced exercise price. The “Premium End Date” means the earliest of: (1) August 19, 2026, (2) the date immediately prior to the closing of a Change in Control (as defined in the Plan), or (3) the date of the employee’s Qualifying Termination. A “Qualifying Termination” means (a) the involuntary termination of the employee’s employment by the Company due to a reduction in force (and other than for Cause (as defined in the Plan)), subject to the employee’s execution of an effective general release of claims in favor of the Company, (b) the employee’s death, or (c) termination of the employee’s employment by the Company following the employee’s Disability (as defined in the Plan). Except for the reduction in the exercise prices of the Repriced Options as described above, the Repriced Options retain their existing terms, including their respective original vesting schedules.

The repricing resulted in a total incremental non-cash stock-based compensation expense of $0.9 million, which was calculated using the Black-Scholes option-pricing model, of which $0.2 million is associated with vested Repriced Options and will be recognized on a straight-line basis through the Premium End Date. The remaining $0.7 million of the incremental non-cash stock-based compensation expense is associated with unvested Repriced Options and will be recognized as follows: (i) if the Premium End Date occurs later than the end of the remaining vesting period of the Repriced Option, the incremental cost will be amortized on a straight-line basis through the Premium End Date, or (ii) if the Premium End Date occurs earlier than the end of the remaining vesting period of the Repriced Option, the incremental cost will be amortized on a straight-line basis over the remaining vesting period. The Company recognized incremental stock-based compensation expense totaling $0.2 million and $0.1 million associated with the 2024 Repricing for the years ended December 31, 2025 and 2024, respectively.

Stock Options

Stock option activity under the Plan and the Predecessor Plan and certain other related information is as follows (in thousands except weighted-average exercise price and remaining term):

Aggregate intrinsic value in the above table is the difference between the estimated fair value of the Company’s common stock as of either December 31, 2025 or 2024, and the exercise price of stock options that had exercise prices below that value.

For the Repriced Options, the calculation of the weighted-average prices and intrinsic value information in the table above is based on the exercise price per share that applied immediately prior to the Repricing Effective Date pending satisfaction of the requisite service requirement.

There wereno options exercised during the year ended December 31, 2025; the options exercised during the year ended December 31, 2024 had an insignificant intrinsic value at exercise.

Employee Stock Purchase Plan

In March 2024, the Company’s board of directors adopted, and the Company’s stockholders approved, the Company’s 2024 Employee Stock Purchase Plan, which became effective in connection with the IPO. The ESPP permits participants to contribute up to a specified percentage of their eligible compensation during a series of offering periods of 24 months, each comprised of foursix-month purchase periods, to purchase shares of the Company’s common stock. The purchase price of the shares will be 85% of the fair market value of the Company’s common stock on the first day of trading of the applicable offering period or on the applicable purchase date, whichever is lower. In addition, the ESPP includes an “evergreen” provision whereby the number of shares of common stock available for issuance under the ESPP will be increased annually on the first day of each calendar year during the term of the ESPP by an amount equal to the lesser of (i)1% of the shares of common stock outstanding on the final day of the immediately preceding calendar year or (ii) such number of shares as determined by the Company’s board of directors or an authorized committee of the board of directors. On January 1, 2026, pursuant to the evergreen provision of the ESPP, the aggregate number of shares authorized for issuance under the ESPP automatically increased by 224,072 shares to 678,991.

The Company recognized stock-based compensation expense related to the ESPP of $0.4 million and $0.5 million for the years ended December 31, 2025 and 2024, respectively.

The Company issued and sold 107,208 and 44,532 shares under the ESPP during the years ended December 31, 2025 and 2024, respectively.

Stock-Based Compensation Expense

Stock-based compensation expense, including the expense related to the ESPP, as recorded in the accompanying statements of operations and comprehensive loss was as follows (in thousands):

As of December 31, 2025, unrecognized compensation cost related to outstanding stock options (all of which have time-based vesting) was $9.2 million, which is expected to be recognized over a weighted-average period of 2.2 years.

As of December 31, 2025, unrecognized compensation cost related to the ESPP was $0.6 million, which is expected to be recognized as expense over approximately 1.3 years.

Excluding any effect of the Repriced Options, except for Repriced Options held by employees who experienced a Qualifying Termination, the weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock options granted during the periods indicated in the table were as follows:

Excluding any effect due to the Repriced Options, except for Repriced Options held by employees who experienced a Qualifying Termination, the weighted-average grant date per share fair value of options granted during the years ended December 31, 2025 and 2024 were $1.88 and $7.19, respectively.

Income Taxes

Income Tax Expense

For the years ended December 31, 2025 and 2024, the Company’s pre-tax loss was entirely domestic. The Company adopted ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, effective January 1, 2025. See Note 1 for additional information regarding the adoption of this standard.

The reconciliation of income taxes computed at the federal statutory rate to the Company’s effective income tax rate for the year ended December 31, 2025, prepared in accordance with ASC 740 as amended by ASU 2023-09, is as follows (in thousands, except percentages):

The reconciliation of income taxes computed at the federal statutory rate to the Company’s effective income tax rate for the year ended December 31, 2024 (prior to adoption of ASU 2023-09) was as follows (in thousands, except percentages):

The majority of our domestic operations are located in the state of California. The Company paidno federal, state, or foreign income taxes, net of refunds received, during the years ended December 31, 2025 and 2024.

As of December 31, 2025, the Company hasnot recorded any current or deferred federal, state, or foreign income tax expense or benefit due to its full valuation allowance against deferred tax assets.

Deferred Tax Assets and Liabilities

Significant components of deferred tax assets and liabilities as of December 31, 2025 and 2024 were as follows (in thousands):

Valuation Allowance

Activity in the valuation allowance for the years ended December 31, 2025 and 2024 was as follows (in thousands):

Net Operating Loss and Credit Carryforwards

The Company has established a full valuation allowance against its net deferred tax assets due to uncertainty regarding realization. In assessing the need for a valuation allowance, management considered the Company’s history of cumulative pre-tax losses, the lack of sufficient taxable income in prior carryback periods, the limited existence of taxable temporary differences, and the uncertainty surrounding future taxable income.

During 2025 and 2024, total deferred tax assets, net of deferred tax liabilities, increased by approximately $16.3 million and $20.5 million, respectively. Due to the full valuation allowance position, the Company’s valuation allowance increased by a corresponding amount in each period.

As of December 31, 2025 and 2024, federal net operating loss (“NOL”) carryforwards, state NOL carryforwards, and research and development tax credit carryforwards consisted of the following (in thousands):

Federal net operating loss carryforwards are subject to potential limitations under Section 382 of the Internal Revenue Code of 1986, as amended (“IRC”). Certain state NOL carryforwards begin to expire in 2038. Federal research tax credits begin to expire in 2040, while unused state credits carry forward indefinitely.

Section 382 Limitations

Pursuant to IRC Sections 382 and 383, the Company’s ability to use its NOL and research tax credit carryforwards to offset future taxable income may be limited if the Company experiences a cumulative change in ownership of more than 50% within a three-year testing period. The Company has not completed an ownership change analysis pursuant to IRC Section 382. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of NOL and research tax carryforwards available to offset future taxable income and income tax liabilities in future years may be significantly reduced, restricted, or eliminated. The Company has also not performed a formal research and development credit study with respect to these credits. As such, the amount of such credits may be reduced in the future should the Company complete such a study. Moreover, deferred tax assets associated with such NOLs and research tax credits could be significantly reduced upon realization of an ownership change within the meaning of IRC Section 382.

Recent Tax Legislation

On July 4, 2025, the reconciliation bill commonly referred to as the One Big Beautiful Bill Act (“OBBBA”) was signed into law in the United States. The OBBBA includes a broad range of tax reform provisions affecting U.S. corporate income taxation. Certain provisions became effective beginning in 2025, including an elective deduction for domestic research and development expenditures, reinstatement of 100% first-year bonus depreciation, and repeal of the fiscal year-end requirement for certain non-U.S. corporations. Other provisions of the OBBBA will become effective in 2026 and subsequent years, including a more favorable tax rate applicable to Foreign-Derived Deduction Eligible Income and income from non-U.S. subsidiaries (Net CFC Tested Income).

Due to the Company’s full valuation allowance on deferred tax assets, the enactment of the OBBBA did not have a material impact on the Company’s financial statements for the year ended December 31, 2025, other than the reclassification of certain deferred tax assets and liabilities.

There are no accruals for interest or tax penalties in the accompanying balance sheets, and the Company has not recognized any such interest or tax penalties in the accompanying statements of operations and comprehensive loss. Although it is not currently under a tax examination, all of the Company’s tax years remain open to audit in all of the tax jurisdictions in which it operates due to the Company’s net operating losses carryforwards.

Uncertain Tax Benefits

Activity related to the Company’s gross unrecognized tax benefits for the years ended December 31, 2025 and 2024 was as follows (in thousands):

The Company recognizes interest and penalties related to uncertain tax positions as a component of income tax expense. As of December 31, 2025 and 2024, the Company hadno accrued interest or penalties.

The Company is not currently under examination by any taxing authority. Due to the existence of net operating loss carryforwards, all tax years remain open to examination in the jurisdictions in which the Company operates.

Net Loss Per Common Share

The following table summarizes the calculation of basic and diluted net loss per common share attributable to common stockholders (in thousands, except per share data):

The Company excluded approximately 4,234,000 and 3,818,000 shares of common stock underlying outstanding stock options from the calculation of diluted net loss per share for the years ended December 31, 2025 and 2024, respectively, because their inclusion would have been anti-dilutive.

Segment Information

The CODM reviews the budget versus actual expense by nature of expense. The following table sets forth our segment loss disclosure for the years ended December 31, 2025 and 2024 (in thousands):

(1)

Includes expenses such as software licenses, database subscriptions, lab service contracts, travel, and other costs.

(2)

Includes expenses such as travel, investor relations services, software licenses, employee training and development, and other costs.