BridgeBio Oncology Therapeutics, Inc.

1. Organization

Description of the Business

BridgeBio Oncology Therapeutics, Inc. (“BBOT,” the “Company,” “we,” “our,” or “us”), formerly known as Helix Acquisition Corp. II (“Helix”), is a clinical-stage biopharmaceutical company advancing a next-generation pipeline of novel small molecule therapeutics targeting RAS and Phosphoinositide 3-kinase (“PI3K”) malignancies. BBOT is headquartered in South San Francisco, California.

de-SPAC Transaction

On February 28, 2025, TheRas Inc. (“Legacy BBOT”), a privately held Delaware corporation, entered into a definitive business combination agreement (“Business Combination Agreement”) with Helix, a publicly traded special purpose acquisition company (“SPAC”) listed on Nasdaq under the ticker symbol “HLXB.”

On August 11, 2025 (the “Closing”), Helix II Merger Sub, Inc., a wholly owned subsidiary of Helix, merged with and into Legacy BBOT, with Legacy BBOT surviving the merger as a wholly-owned subsidiary of Helix (“Merger”). In connection with the Merger, Helix changed its name to BridgeBio Oncology Therapeutics, Inc., and the combined company became listed on Nasdaq under the new ticker symbol “BBOT” (“de-SPAC Transaction”). Immediately prior to the closing of the de-SPAC Transaction, Helix issued and sold shares of its common stock to investors in a private placement financing for an aggregate purchase price of$260.9 million (“PIPE Financing”).

The de-SPAC Transaction was accounted for as a reverse recapitalization with Legacy BBOT being the accounting acquirer, and Helix identified as the acquired company for accounting purposes (see Note 3). Accordingly, prior to the Closing, all historical financial information presented in the condensed consolidated financial statements represents the balances and activity of Legacy BBOT. At the Closing, each outstanding share of Legacy BBOT common stock was exchanged for shares of BBOT common stock based on a ratio of approximately 0.0889 (“Consideration Ratio”). For periods prior to the Closing, the reported share and per share information has been retroactively adjusted to reflect the Consideration Ratio.

Material Related Party Transactions

BridgeBio Pharma, Inc. is a commercial-stage biopharmaceutical company founded to discover, create, test, and deliver transformative medicines to treat patients who suffer from genetic diseases. BridgeBio Pharma, Inc. and its controlled entities (collectively, “BridgeBio Pharma”) were related parties of Legacy BBOT prior to the Closing and remained related parties of the Company after the Closing. As discussed in Note 12, the Company had material related party transactions with BridgeBio Pharma during the periods presented in these condensed consolidated financial statements.

Basis of Presentation and Principles of Consolidation

These condensed consolidated financial statements are prepared in accordance with generally accepted accounting principles in the United States (“US GAAP”) for interim financial information. All costs, as well as assets and liabilities directly associated with the Company’s business activity, are included in the condensed consolidated financial statements. In connection with the de-SPAC Transaction, as the successor entity following the Closing, BBOT became the reporting entity and consolidates the balances and activity of Legacy BBOT. The financial information presented in these condensed consolidated financial statements reflects the balances and results of operations of the combined entity post-Merger. Prior to the Closing, all references to BBOT or the Company are related to the balances and activity of Legacy BBOT. All intercompany balances have been eliminated in consolidation.

These condensed consolidated financial statements have been prepared on the same basis as the 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 information. The results for the three months ended March 31, 2026 are not necessarily indicative of results to be expected for the year ending December 31, 2026 or for any other future annual or interim period.

From its inception through the issuance of the Series B on April 30, 2024, Legacy BBOT had been majority-owned and controlled by BridgeBio Pharma.

Prior to April 30, 2024, the Company operated as part of BridgeBio Pharma. From inception through April 30, 2024, these condensed consolidated financial statements have been derived from BridgeBio Pharma’s historical accounting records and are presented on a carve-out basis. The condensed consolidated statement of operations includes allocations of certain general and administrative expenses to the Company from BridgeBio Pharma. The allocations have been determined on a reasonable basis. The related transactions are discussed further in Note 12. Following the Series B issuance, no individual investor or related party group held a controlling financial interest in the Company, and BBOT has operated independently from BridgeBio Pharma. Subsequent to April 30, 2024 and prior to the de-SPAC Transaction, the financial information included in these condensed consolidated financial statements relates to Legacy BBOT on a standalone basis.

Liquidity

Since its inception through March 31, 2026, the Company has incurred net losses. As of March 31, 2026, the Company had an accumulated deficit of$398.7 million and incurred net losses of$42.1 million and$22.1 million during the three months ended March 31, 2026 and March 31, 2025, respectively. As of March 31, 2026, the Company had a balance of cash, cash equivalents, and marketable securities of$388.9 million. The Company believes that its existing cash, cash equivalents, and marketable securities will be sufficient to support operations for at least one year from the issuance date of these condensed consolidated financial statements.

The Company expects to incur additional losses and negative cash flows for the foreseeable future as it continues its research and development efforts, advances its product candidates through preclinical and clinical development, enhances its approach and programs, expands its product pipeline, seeks regulatory approval, prepares for commercialization, hires additional personnel, protects its intellectual property, operates as a public company, and grows its business. The Company will need to raise additional capital to support its continuing operations and pursue its long-term business plan, including the development and commercialization of its product candidates if approved. Financing activities may include, but are not limited to, public or private equity offerings, debt financings, potential collaborations, licensing agreements, or other sources. Such activities are subject to significant risks and uncertainties.

2. Summary of Significant Accounting Policies

The Company’s significant accounting policies are disclosed in the Company’s consolidated financial statements for the year ended December 31, 2025, and related notes. There have been no material changes to the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s consolidated financial statements for the year ended December 31, 2025 included in the Company's Annual Report on Form 10-K filed with the SEC on March 5, 2026 (the "Form 10-K").

Concentration of Credit Risk and Other Risks and Uncertainties

Cash, cash equivalents, marketable securities, and restricted cash are financial instruments that subject us to significant concentrations of credit risk. These financial instruments are held in financial institutions in the United States. At times, the amounts on deposit may exceed federally insured limits. We believe that these financial institutions are financially sound, and, accordingly, minimal credit risk exists with respect to the amounts deposited. The Company has not experienced any credit losses associated with its balances in such accounts through March 31, 2026.

We are subject to certain risks and uncertainties, and we believe that changes in any of the following areas could have a material adverse effect on future financial position or results of operations: ability to obtain future financing, regulatory approval and market acceptance of, and reimbursement for, product candidates, performance of third-party contract research organizations and manufacturers upon which we rely, protection of our intellectual property, litigation or claims against us based on intellectual property, patent, product, regulatory, clinical or other factors, and our ability to attract and retain employees necessary to support our growth.

We depend on third-party manufacturers to supply products for research and development activities in our programs. Specifically, we rely on and expect to continue relying on a small number of manufacturers to supply our requirements for active pharmaceutical ingredients and formulated drugs related to these programs. A significant interruption in the supply of active pharmaceutical ingredients and formulated drugs could adversely affect these programs.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and disclosure of contingent liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting period. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to:

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Accruals for research and development activities and contingent clinical, development, regulatory, and sales-based milestone payments in our in-licensing agreements,

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The fair value of redeemable convertible preferred stock and common stock prior to the de-SPAC Transaction,

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The fair value of share-based awards and participation right liability,

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Recoverability of deferred tax assets,

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Allocations of operating expenses, and

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The determination of the incremental borrowing rate used in lease-related calculations.

The Company bases its estimates on historical experience and various other reasonable assumptions. Actual results may differ from those estimates or assumptions.

Cash, Cash Equiva lents, and Restricted Cash

The Company considers all highly liquid investments purchased with a maturity of three months or less at the date of purchase to be cash equivalents. As of March 31, 2026, cash and cash equivalents consisted of money market funds, commercial paper, and corporate debt securities. As of December 31, 2025, cash and cash equivalents consisted of money market funds and commercial paper. Restricted cash represented security deposits in the form of a letter of credit issued in connection with the Company’s lease agreement. The cash, cash equivalents, and restricted cash balance included the following (in thousands):

Marketable Securities

The Company generally invests its excess cash in money market funds and investment grade short to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term marketable securities or long-term marketable securities on the condensed consolidated balance sheets, are considered available-for-sale. The Company classifies investments in securities with remaining maturities of less than one year, or where its intent is to use the investments to fund current operations or to make them available for current operations, as short-term investments. The Company classifies investments in securities with remaining maturities of over one year as long-term investments, unless intended to fund current operations.

Our available for-sale securities are carried at fair value with the unrealized gains and losses included in accumulated other comprehensive income as a component of stockholders’ equity until realized. Realized gains and losses are calculated using the specific identification method and recorded as interest income in the condensed consolidated statement of operations.

The Company reports the accrued interest receivable as a component of prepaid and other assets on its condensed consolidated balance sheet, which is presented separately from available-for-sale securities. The Company does not measure an allowance for credit losses on accrued interest receivable and instead writes it off if an issuer defaults or is expected to default on payments.

For available-for-sale securities in an unrealized loss position, the Company first assesses whether it intends to sell, or if 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 income or 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, changes in interest rates, market conditions, 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 interest income through an allowance account. Any impairment that has not been recorded through an allowance for credit losses is included in other comprehensive income or loss. No allowance for credit losses has been recorded as of March 31, 2026 or December 31, 2025.

Fair Value Measurements

Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based on the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability 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. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

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Level 1 - Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

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Level 2 - Inputs (other than quoted prices included in Level 1) that are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active; and

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Level 3 - Unobservable inputs supported by little or no market activity and significant to the fair value of the assets or liabilities.

To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment we exercise in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Due to their short-term nature, the carrying amounts of cash, cash equivalents, prepaid expenses and other current assets, accounts payable, and other accrued liabilities in the accompanying condensed consolidated balance sheet approximate their fair values.

Leases

The Company determines if an arrangement contains a lease at inception and the classification of the lease on the commencement date. An arrangement contains a lease if there is an identified asset and if the Company controls the use of the identified asset throughout the period of use. The Company determines whether leases meet the classification criteria of a finance or operating lease considering: (1) whether the lease transfers ownership of the underlying asset to the lessee at the end of the lease term, (2) whether the lease grants the lessee an option to purchase the underlying asset that the lessee is reasonably certain to exercise, (3) whether the lease term is for a major part of the remaining economic life of the underlying asset, (4) whether the present value of the sum of the lease payments and residual value guaranteed by the lessee equals or exceeds substantially all of the fair value of the underlying asset, and (5) whether the underlying asset is of such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. As of March 31, 2026, our lease population consisted primarily of real estate operating leases. Lease right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of the future minimum lease payments over the lease term at the commencement date. Right-of-use assets also include any initial direct costs incurred and any lease payments made on or before the lease commencement date, less any lease incentives received. Lease incentives are included in the calculation of lease liability as of the commencement date to the extent it is probable that the Company will utilize them.

In determining the present value of its lease liabilities, the Company uses its incremental borrowing rate when the rate implicit in the lease is not readily determinable, based on information available as of the lease commencement date. The Company’s incremental borrowing rate is based on the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment, and the determination of the rate requires the Company to make certain assumptions and judgments, including on its synthetic credit rating. Leases may include options to extend or early terminate the lease term. If the Company, using judgment, is reasonably certain that an option will be exercised, then the option will be included in the calculation of the lease term.

The Company elected to combine lease and non-lease components for office leases, and not to recognize right-of-use assets or lease liabilities for short-term leases. A short-term lease is a lease that, at the commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise. Lease expense for operating leases is recognized on a straight-line basis over the lease term.

Property and Equipment, net

Property and equipment are stated at cost, net of accumulated depreciation. Depreciation of property and equipment is calculated using the straight-line method over the asset’s estimated useful life. Our property and equipment consist of purchased software with an estimated useful life of 3 years, lab equipment with an estimated useful life of 5 years and leasehold improvements amortized over the shorter of 5 years or the remaining lease term. Maintenance and repairs that do not improve or extend the life of the assets are expensed when incurred. Depreciation expense for property and equipment was $0.1 million for both the three months ended March 31, 2026 and 2025, respectively.

Impairment of Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount of an asset group to the future net undiscounted cash flows the assets are expected to generate. If the carrying amount of an asset group exceeds its estimated future cash flows, an impairment charge is recognized in the amount by which the carrying amount of the asset group exceeds the fair value of the asset group. No impairment charges related to long-lived assets have been recorded during the three months ended March 31, 2026 and 2025.

Segments

The Company operates in one operating and reportable segment within the United States, developing oncology therapies through various related development projects. All of the Company’s assets are located in the United States. The single operating segment conclusion is further supported by the Company’s organizational and management structure and other factors. The Company’s chief operating decision-maker is its Chief Executive Officer, who manages operations, allocates resources, and evaluates financial performance using a top-down approach and by setting and reviewing company-wide targets. Subsequent to the completion of the de-SPAC Transaction, during the third fiscal quarter of 2025, the Company changed the segment information regularly provided to the chief operating decision maker to the below aggregated grouping of expense categories, which is the basis on which the chief operating decision-maker assesses segment performance and allocates resources. The prior period information has been recast to reflect this update. The chief operating decision-maker reviews research and development expenses by the following significant categories presented in the table below (in thousands):

Since the Company operates in a single operating and reportable segment represented by the entire entity, significant segment expenses are provided to the chief operating decision-maker using the same basis as presented in the condensed consolidated statements of operations, including the research and development itemization above. Net loss is the key measure of segment profit and loss that the chief operating decision-maker uses to allocate resources, assess performance, monitor expenditures, and conduct a review of budget versus actual analysis. The chief operating decision-maker does not review assets at a different level or category other than the amounts disclosed in the Company’s condensed consolidated balance sheets.

Receivables from and Payables to Related Parties

Receivables from and payables to related parties represent the amounts due to and from various BridgeBio Pharma entities, which are expected to be settled in cash within 12 months from the reporting date.

Prior to April 30, 2024, receivables from related parties represented receivables under the centralized cash management balances used by BridgeBio Pharma for cash management and to finance its operations. These arrangements may not reflect how the Company would have financed its operations had it been a separate, standalone entity during the applicable periods. Changes in related-party receivables arising from cash pooling arrangements are presented as investing activities in the condensed consolidated statements of cash flows. Subsequent to April 30, 2024, receivables from related parties represent amounts due from various BridgeBio Pharma entities for services rendered by the Company under the transition services agreement. Payables to related parties represent the amounts due for various research and development and administrative services performed by BridgeBio Pharma to the Company. Prior to April 30, 2024, none of BridgeBio Pharma’s third-party debt and related interest has been attributed to the Company because the Company is not the legal obligor of the debt, and the borrowings are not specifically identifiable to the Company.

Subsequent to April 30, 2024, the Company continued its relationship with various BridgeBio Pharma entities, which remain related parties. While the nature of these interactions shifted from centralized cash management to services provided under the transition services agreement, the resulting receivables and payables reported separately as current assets or liabilities in the condensed consolidated balance sheets.

Research and development costs are expensed as incurred. Research and development expenses consist of salaries, benefits, and other personnel-related costs, including stock-based compensation, laboratory supplies, preclinical studies, clinical trials, and related clinical manufacturing costs, costs related to manufacturing preparations, fees paid to other entities to conduct certain research and development activities on our behalf, and allocated facility and other related costs. Non-refundable advance payments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized as prepaid expenses until the related goods are delivered or services are performed.

Accrued Research and Development Liabilities

We record accruals for estimated costs of research and development activities performed by third-party service providers, including preclinical studies, clinical trials, and contract manufacturing. We record the estimated costs of research and development activities based on the estimated amount of services provided but not yet invoiced and include these costs in accrued research and development liabilities in the condensed consolidated balance sheets and within research and development expenses in the condensed consolidated statements of operations and comprehensive loss. These costs are a significant component of our research and development expenses. Examples of estimated research and development expenses that we accrue include:

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Fees paid to contract research organizations (“CROs”) in connection with preclinical and toxicology studies and clinical trials;

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Fees paid to investigative sites in connection with clinical trials;

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Fees paid to contract manufacturing organizations in connection with the production of product and clinical trial materials; and

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Professional service fees for consulting and related services.

We base our expense accruals for clinical trials on estimates of services received and efforts expended under contracts with multiple research institutions and CROs that conduct and manage clinical trials on our behalf. The financial terms of these agreements vary from contract to contract and may result in uneven payment flows. Payments under some of these contracts depend on factors such as patient enrollment and the completion of clinical trial milestones. Our service providers generally invoice us monthly in arrears for services performed. In accruing service fees, we estimate the period over which services will be performed and the level of effort to be expended in each period. If we do not identify costs we have already incurred, or if we underestimate or overestimate the level of services performed or the costs of those services, our actual expenses could differ from our estimates. We record advance payments to service providers as prepaid assets.

Werecord accruals for the estimated costs of third-party contract manufacturing activities. The financial terms of these agreements are negotiable, vary from contract to contract, and may result in uneven payment flows to our vendors. Payments under the contracts include upfront payments and milestone payments, which depend on factors such as the completion of certain stages of the manufacturing process. To recognize an expense, we assess whether the production process is sufficiently defined to be the delivery of a good or a service, given that processes and yields are developing and less certain. If we consider the process to be the delivery of a good, we recognize the expense when the drug product is delivered, or we otherwise bear the risk of loss. If we consider the process to be the delivery of a service, we recognize expenses based on our best estimates of the contract manufacturer’s progress through the contract stages. We base our estimates on the best information available at the time. However, additional information may become available to us, enabling us to make a more accurate estimate in future reporting periods. In this event, we may be required to record adjustments to research and development expenses in future reporting periods when the actual level of activity becomes more certain.

Anyincreases or decreases in cost are generally considered to be changes in estimates and will be reflected in research and development expenses in the reporting period identified.

General and Administrative Expenses

General and administrative expenses represent salaries, benefits, and other personnel-related costs, including stock-based compensation, fair value of common stock issued to BridgeBio Pharma (refer to Note 12), costs related to third-party service providers, and professional and legal fees.

Asset Acquisitions

The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. The costs allocated to acquire in-process research and development (“IPR&D”) with no alternative future use are expensed as research and development as of the asset acquisition date. Contingent consideration payments for asset acquisitions include development, regulatory, and sales-based milestone payments due upon the occurrence of a specific event. Contingent payments are recognized when the milestone is met unless the contingent consideration meets the definition of a derivative, in which case the amount becomes part of the cost of the asset acquired. None of the contingent payments represented a derivative through March 31, 2026. Upon recognition of the contingent consideration payment, the amount is expensed as research and development expense if it relates to IPR&D with no alternative future use or capitalized if it relates to a developed product, which is generally when clinical trials have been completed and regulatory approval obtained.

Milestone Payments Under In-Licensing Agreements

Under our in-licensing agreements, the Company is required to pay development, regulatory, and sales-based milestone payments upon the achievement of certain substantive milestones. We recognize development milestones once they are achieved.

Stock-Based Compensation

Stock-based compensation is recorded in research and development expenses or general and administrative expenses based on the grantee's function.

Stock-based compensation includes expenses related to common stock options granted by the Company. The associated stock-based compensation is generally recognized on a straight-line basis over the requisite service period, which is generally the vesting period. Forfeitures of share -based awards are accounted for as they occur. The fair value of stock options is estimated on the grant date using the Black-Scholes option-pricing model, which requires certain assumptions further discussed below:

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Fair Value of Common Stock — Prior to the de-SPAC Transaction, the fair value of the Company’s common stock was determined by the board of directors (“Board”) with input from management and consideration of third-party valuation reports. In the absence of a public trading market, and as a clinical-stage company with no significant revenues, the Company believes that it was appropriate to consider a range of factors to determine the fair market value of the common stock at each grant date. In addition, the Company considered various objective and subjective factors, along with input from the independent third-party valuation firm. The factors included (1) the achievement of the development milestones by the Company; (2) the significant risks associated with the Company’s stage of development; (3) capital market conditions for comparable, privately held, early-stage life science companies; (4) the Company’s available liquidity, financial condition, and results of operations; (5) the sales of the Company’s shares to third parties, such as the Series B financing; and (6) the preferential rights of the redeemable convertible preferred stockholders. Following the de-SPAC Transaction, the Company became a public entity and derives fair value of its common stock from quoted prices on the Nasdaq.

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Expected Dividend Yield — The Company has historically paid no dividends and does not anticipate paying dividends in the future.

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Expected Equity Volatility — The Company does not have sufficient trading history for its common stock and has computed expected volatility based on the historical volatility of a representative group of public companies with similar characteristics to the Company (e.g., public entities of similar size, complexity, stage of development, and industry focus). The historical volatility is commensurate with the expected term assumption.

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Risk-Free Interest Rate — The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of award grant for the expected term of the award.

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Expected Term — The Company uses the simplified method to calculate the expected term for options granted to employees as it does not have sufficient historical exercise data to provide a reasonable basis for estimating the expected term.

Accrued Milestone Compensation Arrangements

Historically we have had performance-based milestone compensation arrangements with certain employees and consultants, whose vesting is contingent upon meeting various regulatory and development milestones, with fixed monetary amounts known at inception that can be settled upon achievement of certain contingent milestones in the form of (1) cash, (2) equity of BridgeBio Pharma, or (3) cash or equity of BridgeBio Pharma or the Company at the issuer’s sole election. No performance milestone awards that may be settled in the Company’s shares or related liabilities were outstanding as of March 31, 2026 or December 31, 2025.

For arrangements that involve settlement by cash or equity of BridgeBio Pharma or the Company at their sole election, the Company classifies the milestone compensation arrangements as liability-classified awards when they are assessed as probable of achievement due to the possible fixed monetary settlement outcomes. The arrangements could also result in a settlement with a variable number of shares based on the then-current stock price at the achievement date of each contingent milestone, should we elect to settle in equity.

We record accruals for the compensation expense arising from each development milestone when the specific contingent development milestone is probable of achievement, and such accruals are measured at each reporting period. We estimate the probability of achieving such milestones based on the progression and expected outcome of the related clinical programs. We base our estimates on the best available information at that time. However, additional information may become available to us which may allow us to make a more accurate estimate in future periods. In this event, we may be required to record adjustments to milestone compensation expenses in future periods. Any increases or decreases in such expenses are generally considered to be changes in estimates and will be reflected in the reporting period identified.

Participation Right Liability

The Company’s participation right liability represented the right granted to a third party to potentially participate in future Series B offerings at a fixed price of$8.8554 per share. The participation right was a freestanding instrument substantially similar to a written call option on the Series B shares that may be redeemed outside of the Company’s control. As such, the Company classified the participation right as a liability, remeasured at fair value, until its full exercise and settlement, which occurred in April 2025. Changes in the fair value of the participation right liability are presented separately in the condensed consolidated statements of operations during the three months ended March 31, 2025. On the settlement date, in April 2025, the participation right liability was remeasured to the intrinsic value of the shares issued and reclassified to temporary equity.

Income Taxes

The Company is subject to U.S. federal and state income taxes as a corporation. The Company’s tax provision and the resulting effective tax rate for interim periods is determined based upon its estimated annual effective tax rate adjusted for the effect of discrete items arising in that quarter. There was no provision for income tax for the three months ended March 31, 2026 or 2025.

Income taxes are accounted for under the asset-and-liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the carrying amounts of existing assets and liabilities in the condensed consolidated financial statements, their respective tax bases, and net operating loss and tax credit carryforwards. Deferred tax assets and liabilities are determined based on the difference between the carrying amounts under U.S. GAAP and the tax basis of assets and liabilities and are measured using the enacted tax rate expected to apply to taxable income in the years in which the differences are expected to be reversed. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized.

We evaluate our deferred tax assets regularly to determine whether adjustments to the valuation allowance are appropriate due to changes in facts or circumstances, such as changes in expected future pre-tax earnings, tax law, interactions with taxing authorities, and developments in case law. In making this evaluation, we rely on our recent history of pre-tax earnings or losses. Our material assumptions include forecasts of future pre-tax earnings and the nature and timing of future deductions and income represented by deferred tax assets and liabilities, all of which involve judgment. Although we believe our estimates are reasonable, we are required to exercise significant judgment in determining the appropriate valuation allowance for deferred tax assets.

We recognize uncertain income tax positions at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. Changes in recognition or measurement are reflected in the period in which judgment occurs. Our policy is to recognize interest and penalties related to the underpayment of income taxes as a component of the provision for income taxes. To date, no interest or penalties have been recorded concerning unrecognized tax benefits.

Net Loss per Share Attributable to Common Stockholders

Prior to the Closing of the de-SPAC Transaction, the Company applied the two-class method to compute net loss per share, as it had issued redeemable convertible preferred stock that met the definition of participating securities. The two-class method required income available to common shareholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Upon the de-SPAC Transaction, the outstanding redeemable convertible preferred stock was converted into common stock, and the two-class method is no longer applicable.

At the Closing, each outstanding share of Legacy BBOT common stock was exchanged for shares of BBOT common stock based on a ratio of approximately 0.0889 (“Consideration Ratio”). For periods prior to the Closing, the reported share and per share information has been retroactively adjusted to reflect the Consideration Ratio (refer to Note 3).

Basic net loss per share attributable to common shareholders is computed by dividing the net loss attributable to common shareholders by the weighted average number of common shares outstanding for the period. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of common shares outstanding, adjusted for the effect of potentially dilutive common shares, including stock options and other equity-linked instruments. Potentially dilutive common shares are not assumed to be issued if their effect is anti-dilutive. As such, in periods in which the Company reported a net loss, diluted net loss per share attributable to common stockholders was the same as basic net loss per share attributable to common stockholders because the effects of potentially dilutive securities were anti-dilutive.

Redeemable Convertible Preferred Stock

The Company initially records redeemable convertible preferred stock at fair value on the dates of issuance, less issuance costs. Prior to the de-SPAC Transaction, the preferred stockholders, as a group, controlled the Company’s Board and had the ability to initiate a deemed liquidation event, such as a change in control or transfer of substantially all of the Company’s assets. Upon a deemed liquidation event, the preferred stockholders as a group could cause the redeemable convertible preferred stock to be redeemed for cash and other assets available for distribution. Based on these considerations, the redeemable convertible preferred stock was classified in temporary equity outside of the stockholders’ equity in the accompanying condensed consolidated balance sheets. Subsequent adjustments to the carrying values of the redeemable convertible preferred stock classified in temporary equity are made only if it becomes probable that such liquidation events would occur, causing the shares to become redeemable. No such adjustments were made since the underlying events were not probable while the redeemable convertible preferred stock was outstanding.

The Company also evaluated the features of its redeemable convertible preferred stock to determine whether they required bifurcation from the underlying shares by assessing whether they were clearly and closely related to the underlying shares and whether they met the definition of a derivative. The Company concluded that no features of its outstanding redeemable convertible preferred stock required bifurcation and separate accounting.

In determining if an extinguishment or modification of changes to the temporary equity-classified preferred stock had occurred, the Company had elected a policy to evaluate if changes added, deleted, or significantly changed a substantive contractual term (e.g., one that was at least reasonably possible of being exercised), or fundamentally changed the nature of the redeemable convertible preferred stock. This evaluation considered both the expected economics and the business purpose of the amendment.

Other Comprehensive Income or Loss

Other comprehensive income or loss represents the change in the Company’s stockholders’ equity (deficit) from all sources other than investments by or distributions to stockholders. The Company’s other comprehensive income or loss is the result of unrealized gains and losses on marketable securities.

Deferred de-SPAC Transaction Costs

The Company capitalized certain directly attributable legal, accounting, and other third-party fees associated with the de-SPAC Transaction as deferred transaction costs. Upon Closing of the de-SPAC Transaction, the associated costs capitalized by the Company were recorded to additional paid-in capital as a reduction of the proceeds from the de-SPAC Transaction.

Emerging Growth Company Status

The Company operates as an emerging growth company (“EGC”), as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, EGCs can delay adopting new or revised accounting standards as of effective dates for private companies. The Company historically operated as part of BridgeBio Pharma and adopted new accounting pronouncements using the same timeline as BridgeBio Pharma. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an EGC or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these condensed consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of the effective dates for public companies.

Recently Adopted Accounting Pronouncements

In July 2025, the FASB issued ASU No. 2025-05, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets(“ASU 2025-05”). ASU 2025-05 provides an optional practical expedient for estimating future credit losses based on current conditions as of the balance sheet date and assuming those conditions do not change over the remaining life of the accounts receivable. Entities that elect the practical expedient and, if applicable, make the accounting policy election are required to apply the amendments prospectively. The amendments in ASU 2025-05 were effective for fiscal years beginning after December 15, 2025, including interim periods within those fiscal years. The Company has adopted this guidance effective January 1, 2026 and there was no material impact to the condensed consolidated financial statements and related disclosures.

Recently Issued Accou nting Pronouncements

In November 2024, the FASB issued ASU No. 2024-03, Income Statement – Reporting Comprehensive Income (Topic 220): Disaggregation of Income Statement Expenses(“ASU 2024-03”), which requires public entities to provide disaggregated disclosures of certain expense captions presented on the face of the income statement into specific categories within the footnotes to the financial statements. ASU 2024-03 is effective for the Company’s annual periods beginning on January 1, 2027, and interim periods beginning on January 1, 2028, with early adoption permitted. The ASU may be applied either on a prospective or retrospective basis. The Company is currently evaluating the impact of adopting this new accounting guidance on its condensed financial statements and related disclosures.

In May 2025, the FASB issued Accounting Standards Update No. 2025-03, Business Combinations (Topic 805) and Consolidation (Topic 810): Determining the Accounting Acquirer in the Acquisition of a Variable Interest Entity (“ASU 2025-03”). ASU 2025-03 changes how companies determine the accounting acquirer in certain business combinations involving variable interest entities. The new guidance requires considering the factors used for other acquisition transactions to assess which party is the accounting acquirer. ASU 2025-03 is effective for the Company’s annual reporting periods beginning on January 1, 2027. Early adoption is permitted. The Company is currently evaluating the impact of adopting this new accounting guidance on its condensed financial statements and related disclosures.

In September 2025, the FASB issued ASU 2025-06, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software ("ASU 2025-06"). This standard modernizes the accounting for software costs, including updating guidance on the recognition and measurement of costs incurred in connection with development and implementation activities related to internal-use software. The standard is effective for annual reporting periods beginning after December 15, 2027, including interim reporting periods within those fiscal years. The standard can be adopted retrospectively, prospectively or on a modified prospective basis, and early adoption is permitted as of the beginning of an annual reporting period, provided that the financial statements for that period have not yet been issued or made available for issuance. The Company is currently evaluating the impact of the standard on its condensed financial statements and related disclosures and will determine the appropriate transition method prior to adoption.

3. PIPE Financing and de-SPAC Transaction

Immediately prior to the de-SPAC Transaction described in Note 1, Helix issued and sold to investors in the PIPE Financing 24,343,711 shares of its common stock for gross proceeds of$260.9 million. In connection with the de-SPAC Transaction, Helix redomiciled as a Delaware corporation and de-registered from the Register of Companies in the Cayman Islands, and Legacy BBOT became a wholly-owned subsidiary of Helix. As a result, BBOT, as the combined company, received$112.3 million in net proceeds from the Trust account previously held by Helix. The Company incurred total transaction costs of$12.4 million consisting of legal, accounting, and other professional fees during the year ended December 31, 2025, all of which has been paid as of March 31, 2026. The Company’s total de-SPAC Transaction costs were recorded to additional paid-in capital as a reduction of the deemed proceeds from the PIPE Financing and the Trust Account.

Upon the Closing of the de-SPAC Transaction, the following occurred with respect to the equity of Legacy BBOT:

•

Each outstanding share of Legacy BBOT redeemable convertible preferred stock issued and outstanding as of the Closing date was converted into Legacy BBOT common stock.

•

The shares of Legacy BBOT common stock that were issued and outstanding immediately prior to the Closing were cancelled and converted into the right to receive 38,924,563 shares of the Company’s common stock at the Consideration Ratio;

•

All outstanding and unexercised Legacy BBOT common stock options were converted into an aggregate of 4,078,552 common stock options of the Company with the same terms and conditions, adjusted based on the Consideration Ratio.

Immediately after the Closing, the Company’s outstanding common stock included the following components:

The de-SPAC Transaction was accounted for as a reverse recapitalization under U.S. GAAP because Legacy BBOT was identified as the accounting acquirer and Helix as the accounting acquiree for financial reporting purposes. Accordingly, these condensed consolidated financial statements of the Company are presented as a continuation of the financial statements of Legacy BBOT. The de-SPAC Transaction is presented as the issuance of common stock by BBOT for the net assets of Helix and proceeds from the PIPE Financing, accompanied by a recapitalization and a change in the reporting entity. The net assets of Helix were recorded at historical cost as of the Closing date, with no goodwill or other intangible assets recognized.

Legacy BBOT was determined to be the accounting acquirer based on the following facts and circumstances as of the Closing date:

•

Legacy BBOT stockholders comprised a relative majority of the voting power of BBOT;

•

Legacy BBOT stockholders received the ability to influence decisions regarding the election and removal of members of BBOT’s board of directors;

•

Legacy BBOT stockholders received the right to appoint the majority of the BBOT board of directors;

•

Legacy BBOT’s operations prior to the de-SPAC Transaction comprised the only ongoing operations of BBOT;

•

BBOT substantially assumed the Legacy BBOT name;

•

Legacy BBOT’s headquarters became BBOT’s headquarters;

•

Legacy BBOT’s senior management comprised the senior management of BBOT; and

•

Prior to the Closing, Helix did not meet the definition of a business.

4. Fair Value Measurements and Disclosures

The following tables summarize the Company’s assets and liabilities measured at fair value on a recurring basis by level within the valuation hierarchy (in thousands):

Money market funds and short-term "on-the-run" treasuries in cash equivalents, such as treasury bills, that are highly liquid and actively traded marketable securities that generally transact at a stable $1.00 net asset value, representing their estimated fair value. The fair value of these marketable securities is based upon observable market inputs obtained from third-party pricing services. The pricing services use industry-standard valuation models and observable inputs, including reported trades, broker-dealer quotes, bids or offers on the same or similar securities issuer, credit spreads, benchmark securities, prepayment and default projections based on historical data, and other observable inputs.

The Company's participation right liability was settled in full in April 2025 and was no longer outstanding as of December 31, 2025.

The following tables summarize the amortized cost and fair value of the Company’s cash equivalents and marketable securities by major investment category for the periods indicated (in thousands):

There wereno unrealized gains or losses on cash equivalents as of March 31, 2026, and December 31, 2025. As of March 31, 2026 and December 31, 2025, some of the Company's marketable securities were in an unrealized loss position. These unrealized losses were attributable to changes in interest rates and geopolitical factors rather than credit deterioration. The Company does not intend to sell securities, and it is not more likely than not that it will be required to sell them before recovery of amortized cost, so these losses were considered temporary. All marketable securities with unrealized losses as of each balance sheet date had been in a loss position for less than twelve months. The Company invests in high-quality short-term and long-term marketable securities, all of which have maturities under three years and no history of credit deterioration. No allowance for credit losses was recorded as of March 31, 2026 and December 31, 2025.

5. In-Licensing and Collaboration Agreements

From time to time, the Company enters into asset purchase and license agreements with third parties as a purchaser or licensee. These arrangements are generally accounted for as asset acquisitions, as the fair value of the consideration is concentrated in a single identifiable asset or group of similar identifiable assets. Given their stage of development, these assets typically have no alternative future use and are expensed as of the acquisition date.

The Regents of the University of California License Agreements

In September 2016, the Company entered into a license agreement with Regents of the University of California, San Francisco (“UCSF”) and was granted certain worldwide exclusive licenses to use the licensed compounds (the “UCSF License”). The UCSF License was subsequently amended and terminated in June 2021. However, certain terms survived the termination of the UCSF License. Upon a change of control or an initial public offering, Legacy BBOT was required to make a payment to UCSF (“Indexed Milestone Payment”). The Company believes that no such payment will be due now or in the future.

Under the UCSF License, UCSF received a right but not an obligation to purchase up to 10% of securities in any offering on the same terms as other investors (“Participation Right”), which survived the termination of the UCSF License. Because UCSF was not notified of the Series B financing at the time it was completed in May 2024, the Participation Right was extended through March 29, 2025. As a result, UCSF received the right to purchase up to 2,509,446 shares of the Series B redeemable convertible preferred stock at the original issue price of$8.8554 per share. In March 2025, UCSF elected to exercise the Participation Right in full. The Participation Right was settled in full in April 2025 (refer to Note 8) and was no longer outstanding as of December 31, 2025.

Leidos Biomedical Research License and Cooperative Research and Development Agreements

In March 2017, the Company entered into a cooperative research and development agreement (“Leidos CRADA”) with Leidos Biomedical Research, Inc. (“Leidos”). The Company and Leidos executed subsequent amendments to the Leidos CRADA between January 2018 and September 2025 to clarify the scope and provide for term extensions. In December 2018, the Company and Leidos entered into a license agreement (“Initial Leidos License”), under which the Company was granted certain worldwide exclusive licenses to use the licensed compounds for its drug discovery and development initiatives. The Initial Leidos License was terminated in 2021. The Company and Leidos subsequently entered into three additional license agreements (“Additional Leidos Licenses”), including two related to KRAS G12C inhibitor and PI3Kα breaker compounds that were executed in August 2022, and one related to the PanKRAS inhibitor executed in December 2023. The Leidos CRADA, Initial Leidos License, and Additional Leidos Licenses are referred to as the “Leidos Agreements”. In December 2025, the Company and Leidos executed an amendment to extend the expiration date of the Leidos CRADA by nine months to September 2026. In December 2025, the Company and Leidos amended the Leidos CRADA to introduce an additional $1.5 million in contribution funding payments.

Under the Additional Leidos Licenses, the Company previously incurred initial upfront fees of $1.8 million. The Company is required to pay Leidos annual license maintenance fees of $0.5 million, as well as royalties on net sales for such licensed compounds calculated using low single-digit percentages of annual net sales of licensed products. The Company’s obligation to pay royalties continues on a country-by-country basis until the expiration of all licensed patent rights covering licensed products in such country. Leidos is also entitled to receive a low double-digit percentage of the sublicensing income received by the Company. As of March 31, 2026, the Company is obligated to make contingent milestone payments totaling up to $25.9 million upon the achievement of certain clinical and regulatory milestones.

As of March 31, 2026 and December 31, 2025, the Company recorded a$0.5 million liability for milestones that had been achieved but remained unpaid, which is included in the accrued research and development liabilities in the condensed consolidated balance sheets. The Company recognized research and development expenses of$0.7 million and$1.0 million for the three months ended March 31, 2026 and 2025, respectively, in connection with the Leidos Agreements.

Lawrence Livermore National Security License and Cooperative Research and Development Agreements

In May 2018, the Company entered into a cooperative research and development agreement (“LLNS CRADA”) with Lawrence Livermore National Security, LLC (“LLNS”) to explore new knowledge therapeutics possibilities to KRAS drug discovery utilizing LLNS’s high-performance computing systems. The Company and LLNS executed subsequent amendments to the LLNS CRADA between December 2019 and November 2025 to clarify the scope and provide for term extensions. In July 2022, the Company entered into an exclusive patent license agreement for KRAS G12C inhibitors and an exclusive patent license agreement for PI3Kα breaker compounds. In December 2024, the Company entered into an exclusive license agreement with LLNS for research and development of a Pan KRAS inhibitor. These three agreements are collectively referred to as the LLNS Agreements. In July 2025, BBOT entered into an exclusive license agreement with LLNS for research and development of Pan KRAS inhibitor for non-oncology indications. In November 2025, the Company and LLNS executed three separate amendments to the existing agreements for Pan KRAS inhibitors, PI3Kα breakers, and KRAS G12C inhibitors. These amendments were made to include new patent applications within the scope of patent rights. In November 2025, the Company and LLNS executed an amendment to extend the LLNS CRADA expiration date by six months to June 2026. In January 2026, the Company and LLNS executed an amendment to extend the LLNS CRADA expiration date another twelve months until June 2027 and included additional estimated funding contributions of $5.0 million to be paid by the Company over the remaining term.

Upon execution of the LLNS Agreements, the Company paid initial upfront cash fees of $0.2 million. In addition, under the terms of the LLNS Agreements, the Company is required to pay LLNS certain annual license maintenance fees of $0.1 million and royalties to LLNS on net sales for such licensed compounds. With respect to such royalty obligations, the Company agreed to pay LLNS low single-digit percentage tiered royalties on annual net sales of licensed products, with a minimum royalty requirement ranging between $0.1 million and $0.5 million, depending on the anniversary of the first commercial sale of the products. The Company’s obligation to pay royalties continues on a country-by-country basis until the expiration of all licensed patent rights covering licensed products in such country. LLNS is also entitled to receive half of the Company's sublicensing income, capped at $2.0 million per year for each indication.

As of March 31, 2026, the Company is required to make contingent milestone payments totaling up to $21.8 million upon the achievement of certain clinical, regulatory, and sales milestones.

During the three months ended March 31, 2026, no milestones had been achieved and therefore no liabilities were recorded as of March 31, 2026 on the condensed consolidated balance sheets. The Company recognized research and development expenses of $0.3 million for the three months ended March 31, 2025 in connection with the LLNS Agreements. Research and development expenses for the three months ended March 31, 2026 were immaterial.

6. Income from Transition Services Agreements

In August 2025, we entered into a transition services agreement (“TSA”) with an unrelated party (“TSA Party”) to provide certain services unrelated to our principal operations, which represent the only performance obligation under this arrangement. For the three months ended March 31, 2026, the Company recorded $0.2 million in connection with the TSA, which is presented separately as other income from transition services agreements in the condensed consolidated statements of operations. The Company did not record any TSA income for the three months ended March 31, 2025.

7. Commitments and Contingencies

Other Research and Development Agreements

We may enter into contracts in the normal course of business with contract research organizations for clinical trials, contract manufacturing organizations for clinical supplies, and other vendors for preclinical studies, supplies, and other services and products for operating purposes. These contracts generally provide for termination on notice with potential termination charges.

Cash Bonus with Performance Conditions

In May 2024, the Company committed to making a$3.0 million cash payment to an executive contingent upon the consummation of an equity financing, a change in control transaction, an initial public offering, or a reverse merger with a SPAC. The Company recorded$3.0 million performance cash bonus payment to the executive upon closing of the de-SPAC Transaction, which was paid during the three months ended September 30, 2025. There have been no other cash bonuses with performance conditions recorded or paid during the three months ended March 31, 2026.

Indemni fication

In the ordinary course of business, we may provide indemnifications of varying scope and terms to vendors, lessors, business partners, Board members, officers, and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, services to be provided by us, our negligence or willful misconduct, violations of law, or intellectual property infringement claims made by third parties. No material demands have been made upon us to provide indemnification under such agreements, and thus, there are no claims that we are aware of that could have a material effect on our condensed consolidated financial statements.

Contin gencies

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 is not currently involved in any legal actions that could have a material effect on the Company’s financial position, results of operations, or liquidity.

8. Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit)

Redeemable Convert ible Preferred Stock

In February 2025, one investor elected to voluntarily convert 21,783 shares of the Series B redeemable convertible preferred stock into common stock. In March 2025, UCSF elected to exercise the Participation Right, and the Company settled the Participation Right in full in April 2025 through the issuance of 2,509,446 Series B shares for cash proceeds of$22.2 million, and the amount credited to redeemable convertible preferred stock included the settlement date fair value of the participation right liability of $3.8 million.

In August 2025, the Company’s outstanding redeemable convertible preferred stock was converted into common stock, immediately before the Closing of the de-SPAC Transaction discussed in Note 3, and therefore there were no redeemable convertible preferred stock shares authorized or outstanding as of March 31, 2026 or December 31, 2025.

Prior to the August 2025 conversion, the holders of the redeemable convertible preferred stock were entitled to different rights, preferences, privileges, and restrictions regarding voting, dividends, liquidation, conversion, and redemption.

Voting Rights

Each share of the redeemable convertible preferred stock had voting rights equal to the number of shares of common stock into which it was convertible. The holders of redeemable convertible preferred stock voted together with the holders of common stock as a single class.

Dividends

The holders of the redeemable convertible preferred stock were entitled to receive noncumulative dividends at an annual rate of 8.0% of the original issuance price per share of the respective series when declared by the Company’s Board prior and in preference to any dividends on common stock. The holders of the redeemable convertible preferred stock had priority and were entitled to participate in any distributions to the holders of common stock on an as-converted basis. No dividends have been declared or paid by the Company since its inception and through March 31, 2026.

Redemption

Shares of the redeemable convertible preferred stock were contingently redeemable upon the occurrence of certain change in control events that were outside the Company’s control, including a sale, lease, transfer, or other disposition of all or substantially all of the Company’s assets, merger with a special purpose acquisition company or with a public company (“Deemed Liquidation Event”). The following stockholders group were each required to vote to initiate or waive such redemption: (i) the holders of a majority of the then outstanding shares of the redeemable convertible preferred stock, voting together as a single class on an as-converted into common stock basis (“Requisite Holders”), and (ii) the holders of a majority of the then outstanding shares of the Series B, voting as a separate class (“Requisite Series B Holders”). Subsequent adjustments to the carrying values of the liquidation preferences were only required to be made if it became probable that such a liquidation event would occur. No subsequent measurement adjustments were recorded through August 2025.

Liquidation Preference

In the event of any liquidation, dissolution, or winding up of the Company, either voluntary or involuntary, and upon a Deemed Liquidation Event, the holders of the redeemable convertible preferred stock were entitled to receive, with equal priority among them, prior and in preference to any distribution of any of the Company’s assets to the holders of common stock, an amount equal to the greater of (a) the original issue price per share of redeemable convertible preferred stock of the respective series then outstanding, plus any declared or accrued but unpaid dividends, or (b) an amount payable on an as-converted into common stock basis. After payment of the preferential amounts to the holders of the redeemable convertible preferred stock, the remaining assets of the Company available for distribution were to be distributed among the holders of common stock in proportion to the number of shares then held.

Conversion Rights

At the option of the holder, each share of the redeemable convertible preferred stock was convertible at any time into such number of shares of common stock as determined by dividing the original issue price per share of the respective series by the applicable conversion price. The initial conversion price per share was equal to the original issue price per share of the respective series. The conversion price of the redeemable convertible preferred stock was subject to adjustments for recapitalizations and under anti-dilution provisions contained in the Company’s amended and restated certificate of incorporation.

All outstanding shares of the redeemable convertible preferred stock were subject to automatic conversion into shares of common stock, at the applicable conversion price, upon either of the following: (a) the closing of the sale of shares of common stock at a price per share of at least $17.7109, as adjusted to reflect the Consideration Ratio, in a firm-commitment underwritten public offering under the Securities Act of 1933, as amended, resulting in at least $100.0 million of proceeds to the Company, net of the underwriting discount and commissions, and on a qualified stock exchange, or (b) the date and time, or the occurrence of an event, specified by the Requisite Holders and the Requisite Series B Holders, voting or consenting as two separate groups.

Common Stock

Amendment to Certificate of Incorporation

In April 2025, the Company amended and restated its certificate of incorporation to increase the authorized redeemable convertible preferred stock from 36,386,702 to 38,896,148 shares and the authorized common stock from 41,341,250 to 44,008,427 shares.

In August 2025, in connection with the de-SPAC Transaction, the Company filed a new certificate of incorporation that authorized the issuance of up to 510,000,000 shares with a par value of $0.0001 per share, including 500,000,000 shares of common stock, and 10,000,000 shares of undesignated preferred stock.

Shares Reserved for Issuance

The Company had the following shares reserved for issuance:

9. Leases

In November 2024, the Company entered into an agreement for the lease of approximately 10,934 square feet of office space in South San Francisco, California for 61 months. The Company has the option to renew for an additional four-year term. The renewal option was not reasonably certain to be exercised by the Company and was excluded from the lease term. The lease commenced in March 2025 and will expire in April 2030. The associated lease costs were not material during the three months ended March 31, 2026 and 2025. As of March 31, 2026, the weighted average remaining lease term for the Company’s lease was 4.1 years, and the discount rate used was 7.40%.

The following table presents the amortization of the Company’s lease liabilities recorded in the condensed consolidated balance sheet at of March 31, 2026 (in thousands):

Short-term lease costs were $0.2 million and$0.6 million for the three months ended March 31, 2026 and 2025, respectively.

10. Stock-Based Compensation

Stock-based compensation is included under the following expense categories presented in the condensed consolidated statements of operations (in thousands):

Common Stock Options Issued and Other Equity-Based Awards Issued by the Company

2016 Equity Incentive Plan

In January 2017, the Company adopted the 2016 Equity Incentive Plan (“2016 Plan”). The 2016 Plan provides for the grant of stock-based incentive awards, including common stock options and other forms of stock-based compensation. Any cancelled or forfeited awards under the 2016 Plan become available for future issuances. As of March 31, 2026, no shares were reserved for future issuance under the 2016 Plan.

2025 Stock Option and Incentive Plan

In August 2025, the Company adopted the 2025 Stock Option and Incentive Plan (“2025 Plan”). The 2025 Plan provides for the grant of equity and equity-based incentive awards, such as stock options and other forms of stock-based compensation, to officers, employees, directors, and consultants. Any cancelled or forfeited awards under the 2025 Plan become available for future issuances. As of March 31, 2026,1,521,834 shares were available for future grants under the 2025 Plan.

2025 Employee Stock Purchase Plan

In August 2025, the Company adopted the 2025 Employee Stock Purchase Plan (“ESPP”). Under the ESPP, eligible employees may purchase shares of BBOT’s common stock through payroll deductions at a price equal to 85% of the fair market value of the common stock on the offering date or the exercise date, whichever is less. As of March 31, 2026,1,808,313 shares were available for future grants under the ESPP, and no offering periods had started.

2025 Inducement Plan

In October 2025, the Company adopted the 2025 Inducement Plan (“2025 Inducement Plan”) to be used for grants of equity-based awards to individuals who were not previously its employees or directors as an inducement for entry into employment. Any cancelled or forfeited awards under the 2025 Inducement Plan become available for future issuances. As of March 31, 2026,852,500 shares were available for future grants under the 2025 Inducement Plan.

Outstanding Common Stock Options

The Company had the following common stock options outstanding:

The aggregate intrinsic value in the above table is calculated as the difference between the estimated fair value of the Company’s common stock and the exercise price of the underlying stock options as of each reporting date.

As of March 31, 2026, a total of 1,730,153 common stock options included provisions for accelerated vesting in connection with a qualified change in control of the Company. These instruments included 1,507,214 options, with vesting if the grantee is terminated without cause, as defined in the 2016 Plan, or for good reason, as defined in the grant terms, within 12 months following such a transaction. The remaining 222,939 options vest immediately upon the occurrence of a qualified change in control, excluding events such as an initial public offering or other bona fide financing transactions. The closing of the de-SPAC Transaction described in Note 1 did not constitute a qualified change in control event under these definitions.

The weighted-average grant-date fair value of common stock options granted during three months ended March 31, 2026 was$7.52 per share. The weighted-average grant-date fair value of common stock options vested and forfeited during the three months ended March 31, 2026 was, $4.10 and$6.57 per share, respectively. As of March 31, 2026, there was$61.5 million of unrecognized stock-based compensation related to unvested common stock options, which is expected to be recognized over a weighted-average period of 3.2 years.

There were no grants issued during the three months ended March 31, 2025. The fair value of stock options granted during the three months ended March 31, 2026 were estimated at the grant date using the Black-Scholes option pricing model based on the following assumptions:

Restricted Stock Units

Activity under the 2025 Plan with respect to the Company’s RSUs during the three months ended March 31, 2026 was as follows:

As of March 31, 2026, there was$3.7 million of total unrecognized compensation cost related to RSUs that is expected to be recognized over a weighted average period of 3.8 years.

11. Net Loss Per Share Attributable to Common Stockholders

The following common stock equivalents were excluded from the computation of diluted net loss per share as their impact would have been anti-dilutive:

12. Related Party Transactions

Redeemable Conve rtible Preferred Stock

All shares of the Series Seed redeemable convertible preferred stock and Series A redeemable convertible preferred stock were issued to BridgeBio Pharma and became common stock of the Company upon the Closing of the de-SPAC Transaction.

Common Stock Issued to BridgeBio Pharma

In August 2025, the Company executed an amendment to the transition services agreement with BridgeBio Pharma (“TSA Amendment”). Under the TSA Amendment, BBOT agreed to issue 784,720 shares of the Company’s common stock to BridgeBio Pharma by October 31, 2025 (“TSA Shares”) as a one-time charge related to the Closing of the de-SPAC Transaction. The promise to issue the TSA Shares represented a nonreciprocal transfer since the Company did not receive a commensurate value in exchange for the TSA Shares and was treated as a non-pro-rata distribution to a related party. During the year ended December 31, 2025, the Company recorded$7.8 million, included in general and administrative expenses in the consolidated statements of operations using the closing price of its common stock as of the TSA Amendment date. The promise to issue the TSA Shares was concluded to be equity-classified, and the corresponding credit was recorded to additional paid-in capital. The TSA Shares were issued and became outstanding in October 2025. Under the TSA Amendment, the issuance of the TSA Shares was not contingent on any condition other than the passage of time, and these shares are treated as outstanding for basic and diluted net loss per share calculation purposes from the TSA Amendment date.

Collaborative Arrangement with Related Party

In July 2025, the Company executed a research and collaboration agreement (“RCA”) with a related party (“RCA Party”) to grant a license over its intellectual property with respect to the new indication being developed by the RCA Party (“RCA License”) and perform certain research and development activities (“RCA Service”) intended to achieve an acceptance of an investigational new drug application that will be owned and further developed by the RCA Party. During the three months ended March 31, 2026, the Company recognized$0.1 million in connection with the RCA, which is included as a reduction to research and development expenses in the condensed consolidated statement of operations.

Related Party Income and Expenses

During the three months ended March 31, 2026, the Company recognized $0.1 million in research and development expenses for the services provided by BridgeBio Pharma under the transition services agreement and related amendments.

During the three months ended March 31, 2025, the Company recognized $0.3 million and $0.2 million in research and development expenses and general and administrative expenses, respectively, for the services provided by BridgeBio Pharma.

No related party income was recognized during thethree months ended March 31, 2026 or 2025.