The preparation of financial statements in accordance with GAAP requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to revenue recognition, stock-based compensation, and accrued research and development costs. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

The Company considers all highly liquid investments with original maturities of 90 days or less from the date of purchase to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts. Restricted cash represents cash held as collateral for the letter of credit required under the Company’s facility lease and is reported as a long-term asset in the accompanying balance sheets. Cash and cash equivalents are considered Level 1 investments.

The Company’s marketable securities primarily consist of U.S. Government and corporate debt securities. The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the balance sheets, with unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) within the statements of operations and comprehensive loss and as a separate component of stockholders’ equity. The Company classifies marketable securities with remaining maturities greater than one year as current assets because such marketable securities are available to fund the Company’s current operations. Realized gains and losses are calculated on the specific identification method and recorded as interest income. There were no realized gains and losses recognized during the periods presented.

At each balance sheet date, the Company assesses available-for-sale debt securities in an unrealized loss position to determine whether the unrealized loss or any potential credit losses should be recognized in net income (loss). 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 aforementioned 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, underlying credit ratings and forecasted recovery, among other factors. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded as an allowance in interest income. There have been no impairment or credit losses recognized during the periods presented.

The Company excludes the applicable accrued interest from both the fair value and amortized costs basis of the Company’s available-for-sale securities for purposes of identifying and measuring an impairment. Accrued interest receivable on available-for-sale securities is recorded within prepaid and other assets on the balance sheets. The Company made an accounting policy election to (1) not measure an allowance for credit loss for accrued interest receivable, and (2) to write-off any uncollectible accrued interest receivable as a reversal of interest income in a timely manner, which the Company considers to be in the period in which it determines the accrued interest will not be collected.

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has established guidelines regarding approved investments, credit quality, diversification, liquidity and maturities of investments,

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be 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 2—Observable inputs, such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

None of the Company’s non-financial assets are recorded at fair value on a non-recurring basis. The carrying amounts reflected in the Company’s balance sheets for prepaid and other assets and accounts payable and accrued liabilities approximate their fair values due to their short-term nature. The Company recognizes transfers between levels of the fair value hierarchy on the date of the event or change in circumstances that caused the transfer. There have been no transfers into or out of level 3 assets during any of the periods presented.

Property and 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 ranges from three to five years. Leasehold improvements are amortized on a straight-line basis over the shorter of the estimated useful lives of 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.

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset or an asset group may not be recoverable. If such triggering event is determined to have occurred, the asset’s or asset group’s carrying value is compared to the future undiscounted cash flows expected to be generated. The Company has not recognized any impairment losses in any of the periods presented in these financial statements.

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker (CODM) in making decisions regarding resource allocation and assessing performance. The CODM manages its operations as a single operating segment in the United States for the purposes of assessing performance and making operating decisions.

To date, all the Company’s revenue has been derived from collaboration and research agreements. The terms of these arrangements include the following types of payments to the Company: non-refundable, upfront license fees; development, regulatory and commercial milestone payments; payments for research and development services provided by the Company or for manufacturing supply services the Company provides through its contract manufacturers; and royalties on net sales of licensed products.

At the inception of a collaboration arrangement, the Company first assesses whether the contractual arrangement is within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808) to determine whether the arrangement involves a joint operating activity and involves two (or more) parties that are both active participants in the activity and exposed to significant risks and rewards dependent on the commercial success of such activity. Then the Company determines whether the collaboration arrangement in its entirety represents a contract with a customer as defined by ASC Topic 606 (ASC 606). If only a portion of the collaboration arrangement is potentially with a customer, the Company applies the distinct good or service unit-of-account guidance in ASC 606 to determine whether there is a unit of account that should be accounted for under ASC 606.

The Company performs the following steps in determining the appropriate amount of revenue to be recognized as it fulfills its obligations under each of these agreements: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when, or as, the Company satisfies each performance obligation. The Company applies significant judgment when making estimates and assumptions under these agreements, including (i) evaluating whether contractual obligations represent distinct performance obligations, (ii) the assessment of whether options represent material rights, (iii) determining whether there are observable standalone prices and allocating transaction price to performance obligations within a contract, (iv) assessing whether any licenses are functional or symbolic, (v) determining when performance obligations have been met, and (vi) assessing the recognition of variable consideration. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time.

The Company receives payments from its collaborators based on billing schedules established in each contract. Upfront and other payments may require deferral of revenue recognition to a future period until the Company performs its obligations under its research and collaboration arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional.

License fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments are identified as variable consideration and excluded from the transaction price. The Company will recognize revenue for sales-based royalty if and when a subsequent sale occurs.

Research and development costs are expensed as incurred and include salaries, benefits and stock-based compensation associated with research and development personnel, third-party research and development expenses, license fees, laboratory supplies, facilities, overhead costs, and consultants. Nonrefundable advance payments for goods and services that will be used in future research and development activities are capitalized and recorded as expense in the period that the Company receives the goods or when services are performed.

The Company has entered into various research and development contracts with research institutions, clinical research organizations, clinical manufacturing organizations and other companies. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and payments made in advance of performance are reflected in the accompanying balance sheets as prepaid and other assets or accrued liabilities. The Company records accruals for estimated costs incurred for ongoing research and development activities. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the services, including the phase or completion of events, invoices received, and contracted costs. Significant judgments and estimates may be made in determining the prepaid or accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates.

Upfront and milestone payments to acquire contractual rights to licensed technology are expensed when incurred if there is uncertainty in the Company receiving future economic benefit from the acquired contractual rights. Certain of these contractual rights may require the Company to make additional milestone payments upon initiation of a pivotal trial and the U.S. Food and Drug Administration approval.

Income taxes are accounted for using the asset and liability method. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the differences between the 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. Valuation allowances are provided, if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. 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.

When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit would more likely than not be realized assuming examination by the taxing authority. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances.

The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent Company's right to use an underlying asset for the lease term and lease liabilities represent Company's obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The interest rate used to determine the present value of the future lease payments is our incremental borrowing rate, because the interest rate implicit in most of our leases is not readily determinable. The incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. The operating lease right-of-use asset also includes any lease payments made and excludes lease incentives. The lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. Variable lease payments that do not depend on a rate or index, payments associated with non-lease components, and costs related to leases with terms of less than 12 months are expensed as incurred.

Stock-based compensation expense for stock option grants is determined using the Black-Scholes-Merton (BSM) option pricing model and is recorded at the estimated fair value of the award as of the grant date and recognized as expense on a straight-line basis over the requisite service period (usually the vesting period) of the stock-based award. Stock-based compensation expense for Restricted Stock Units (RSUs) is recorded at the market price of a share of the Company's stock on the date of grant and is recognized as expense on a straight-line basis over the four-year service period. Stock-based compensation expense for Performance Stock Units (PSUs) is recorded at the market price of a share of the Company's stock on the date of grant and recognized on a straight-line basis over the requisite service periods beginning when the achievement of the

performance condition is determined to be probable. Stock-based compensation expense for employee stock purchases under the Company’s ESPP is determined using the BSM option pricing model and is recorded at the estimated fair value of the purchase as of the plan enrollment date and is recognized as expense on a straight-line basis over the applicable six-month ESPP offering period. The estimation of fair value for stock-based compensation requires management to make estimates and judgments about, among other things, the estimated life of options and volatility of the Company’s common stock. These judgments directly affect the amount of compensation expense that will be recognized. Forfeitures are accounted for as incurred.

Comprehensive 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 marketable securities. Comprehensive gains (losses) have been reflected in the statements of operations and comprehensive loss for all periods presented.

Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period, adjusted for the weighted-average number of common shares outstanding that are subject to repurchase or forfeiture. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as inclusion of the common stock equivalent securities would be anti-dilutive.

In November 2023, the Financial Accounting Standards Board (FASB) issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which modifies the disclosure and presentation requirements of reportable segments. The amendments in the update require the disclosure of significant segment expenses that are regularly provided to the CODM and included within each reported measure of segment profit and loss. The amendments also require disclosure of all other segment items by reportable segment and a description of its composition. Additionally, the amendments require disclosure of the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. Lastly, the amendment requires that a public entity that has a single reportable segment provide all the disclosures required by ASU 2023-07 and all existing segment disclosures in Topic 280. This update is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. ASU 2023-07 will be applied retrospectively and early adoption is permitted. The Company is currently evaluating the impact that this guidance will have on the presentation of its financial statements and accompanying notes.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances income tax disclosures, primarily through standardization and disaggregation of the income tax rate reconciliation and disaggregation of income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024. ASU 2023-09 can be applied either prospectively or