Equillium, Inc.

1. Organization and Accounting Pronouncements

Description of Business

Equillium, Inc., together with its wholly owned subsidiaries (the Company), was incorporated in the state of Delaware on March 16, 2017.

The Company is a biotechnology innovator developing novel therapies to treat severe autoimmune and inflammatory disorders with the mission to develop life-changing therapeutics for patients. The Company's primary goal is to advance EQ504, its novel aryl hydrocarbon receptor modulator, into and through clinical development.

The Company is headquartered in La Jolla, California, and it manages its business as one operating segment. Refer to Note 5 for additional information.

Liquidity and Business Risks

As of September 30, 2025, the Company had $33.1 million in cash and cash equivalents. From inception through September 30, 2025, substantially all of the Company’s efforts have been focused on research, development and the advancement of the Company’s clinical and pre-clinical product candidates. The Company has not yet generated product sales and as a result has incurred significant operating losses and negative cash flows from operations. As a result, the Company has an accumulated deficit of $212.4 million as of September 30, 2025. The Company expects to incur additional losses in the future to conduct research and development for which it will need to raise additional capital to implement.

During the third quarter of 2025, the Company completed an equity financing with gross proceeds of approximately $30 million with the ability to raise an additional $20 million subject to achieving certain clinical and pricing related milestones. Refer to Note 8 for additional information. Management believes that the Company's cash and cash equivalents as of September 30, 2025 will be sufficient to fund operations for at least the next 12 months from the date this Quarterly Report on Form 10-Q is filed with the Securities and Exchange Commission (SEC).

Basis of Presentation

The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the SEC related to a quarterly report on Form 10-Q. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB). Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. The condensed consolidated financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. These condensed consolidated financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2024 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 27, 2025.

Principles of Consolidation

The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Foreign Currency Translation

The Company’s wholly-owned subsidiary in Australia uses its local currency as its functional currency. Assets and liabilities are translated into U.S. dollars at quarter-end exchange rates and revenues and expenses are translated at average exchange rates during the quarter and year-to-date periods. Foreign currency translation adjustments for the reported periods are included in other comprehensive loss, net in the Company’s condensed consolidated statements of comprehensive loss, and the cumulative effect is included in the stockholders’ equity section of the Company’s condensed consolidated balance sheets.

Recently Issued Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. ASU 2023-09 requires annual disclosures of specific categories in the rate reconciliation, additional information for reconciling items that meet a quantitative threshold and a disaggregation of income taxes paid, net of refunds. ASU 2023-09 also eliminates certain existing disclosure requirements related to uncertain tax positions and unrecognized deferred tax liabilities. ASU 2023-09 is effective for the Company beginning with the Company's Annual Report on Form 10-K for the year ending December 31, 2025. Early adoption is permitted. ASU 2023-09 should be applied prospectively. Retrospective adoption is permitted. The Company is currently assessing the impact this standard will have on the Company’s consolidated financial statement disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, to improve disclosures around an entity's expenses. Upon adoption, companies will be required to disclose in the notes to the financial statements a disaggregation of certain expense categories included within the expense captions on the face of the income statement. The standard is effective for annual reporting periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027, with early adoption permitted, and can be applied either prospectively or retrospectively. The Company plans to adopt the standard in its 2027 annual period and is currently assessing the impact this standard will have on the Company's consolidated financial statement disclosures.

No other new accounting pronouncements or legislation issued or effective as of September 30, 2025 have had, or are expected to have, a material impact on the Company’scondensed consolidated financial statements.

2. Summary of Significant Accounting Policies

Segment Information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business inone segment, which is the business of developing novel therapeutics to treat severe immuno-inflammatory disorders with high unmet medical need. See Note 5 for more information on segment reporting.

Use of Estimates

The preparation of the Company’s condensed consolidated financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the condensed consolidated financial statements and accompanying notes. Significant estimates in the Company’s condensed consolidated financial statements relate to accrued research and development expense, revenue recognition and the valuation of equity awards. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

Concentration of Credit Risk and Off-Balance Sheet Risk

Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in which the majority of deposits are in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes the exposure to concentration of credit risk.

Comprehensive Loss

The Company is required to report all components of comprehensive loss, including net loss, in the condensed consolidated financial statements in the period in which they are recognized. 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 investments and foreign currency translation gains and losses. Other comprehensive loss, net includes unrealized gains or losses on short-term investments as well as foreign currency translation gains or losses.

Cash and Cash Equivalents

Cash and cash equivalents include cash in readily available checking and savings accounts, and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. At September 30, 2025 and December 31, 2024, the Company's cash and cash equivalents were primarily comprised of money market funds.

Short-Term Investments

Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in comprehensive loss. The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following (in thousands):

Property and Equipment

Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three tofive years).

Leases

The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For operating leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For the Company's operating leases, if the interest rate used to determine the present value of future lease payments is not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The Company's incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.

Impairment of Long-Lived Assets

Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since inception.

Accrued Research and Development Expense

The Company isrequired to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its condensed consolidated financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the non-clinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and development personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognitionif actual results differ from its estimates. The Company classifies its estimates for accrued research and development expenses as accrued expenses on the accompanying condensed consolidated balance sheets.

Australian Research and Development Tax Incentive

Equillium Australia Pty Ltd (Equillium Australia), a wholly-owned subsidiary of Equillium, Inc., is eligible under the Australian Research and Development Tax Incentive Program (the Tax Incentive) to obtain a cash refund from the Australian Taxation Office (ATO) for eligible research and development expenditures. The cash refund is received by Equillium Australia upon filing of a Tax Incentive claim in connection with Equillium Australia’s annual income tax return.

The Tax Incentive is a self-assess program whereby Equillium Australia must assess each year (i) if the entity is eligible, (ii) if the specific research and development activities are eligible and (iii) if the individual research and development expenditures have nexus to such research and development activities. Equillium Australia evaluates its eligibility under the Tax Incentive as of each balance sheet date based on the most current and relevant data available. Equillium Australia is able to continue to claim refunds under the Tax Incentive for as long as it remains eligible and continues to incur eligible research and development expenditures.

Although Equillium Australia believes that it has complied with all relevant conditions of eligibility under the program for all periods claimed, the ATO has the right to review Equillium Australia’s qualifying programs and related expenditures for a period of up to four years. Additionally, the period open for review is indefinite if the ATO suspects fraud. If such a review were to occur, the ATO may have different interpretations of certain eligibility requirements. If the ATO disagreed with Equillium Australia’s assessments and any related subsequent appeals, it could require adjustment to and potential repayment of current or previous years’ claims already received. If Equillium Australia was unable to demonstrate a reasonably arguable position taken on such claims, the ATO could also assess penalties and interest on potential adjustment amounts. The Company has not provided any allowance for any such potential adjustments, should they occur in the future.

The estimated Tax Incentive refund amounts are recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive refund amounts will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. During the three and nine months ended September 30, 2025, the Company didnot record a reduction to research and development expenses related to the Tax Incentive due to the substantial completion of its EQ101 and EQ102 clinical trials in Australia. During the three and nine months ended September 30, 2024, the Company recorded $0.2 million and $1.6 million, respectively, as a reduction to research and development expenses related to the Tax Incentive. The Company classifies its estimates for the Tax Incentive refunds as prepaid expenses and other current assets on the accompanying condensed consolidated balance sheets. As of September 30, 2025, there wereno amounts recorded within prepaid and other current assets attributed to the Tax Incentive. As of December 31, 2024, the Company recorded $1.0 million within prepaid and other current assets attributed to the Tax Incentive.

Distinguishing Liabilities from Equity

The Company evaluates equity or liability classification for freestanding financial instruments, including warrants and options, pursuant to the guidance under ASC Topic 480, Distinguishing Liabilities from Equity (ASC 480). The Company classifies as liabilities all freestanding financial instruments that are (i) mandatorily redeemable, (ii) represent an obligation to repurchase the Company’s equity shares by transferring assets, or (iii) represent an unconditional obligation (or conditional obligation if the financial instrument is not an outstanding share) to issue a variable number of shares predominantly based on a fixed monetary amount, variations in something other than the fair value of the Company’s equity shares, or variations inversely related to changes in fair value of the Company’s equity shares.

If a freestanding financial instrument does not represent an outstanding equity share and does not meet liability classification under ASC 480, the Company then assesses whether the freestanding financial instrument is indexed to its own stock and meets equity classification pursuant to ASC 815-40, Derivatives and Hedging (ASC 815). The Company further assesses whether the freestanding financial instruments should be classified as temporary equity. Freestanding financial instruments that are redeemable for cash or other assets at a fixed or determinable date, at the option of the holder, or upon the occurrence of an event are classified in temporary equity in accordance with ASC 480. Otherwise, the freestanding financial instruments are classified in permanent equity.

See Note 8, Stockholders' Equity, for additional information on the freestanding financial instruments assessed under ASC 480 and ASC 815-40 for equity or liability classification.

Revenue Recognition

The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company followsa five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. The Company applies the revenue recognition standard, including the use of any practical expedients, consistently to contracts with similar characteristics and in similar circumstances.

Research and Development

Research and development expenses include salaries and related overhead expenses, non-cash stock-based compensation expense, external research and development expenses incurred under arrangements with third parties, costs of services performed by consultants and contract research organizations, and regulatory costs including those related to preparing and filing INDs with the FDA. Research and development costs are expensed as incurred.

Patent Costs

The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the condensed consolidated statements of operations.

Stock-Based Compensation

The Company measures employee and non-employee stock-based awards, including stock options and stock purchase rights, at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the award. The Company uses the Black-Scholes option pricing model to value its stock option awards. Estimating the fair value of stock option awards requires management to apply judgment and make estimates of certain assumptions, including the volatility of the Company’s common stock, the expected term of the Company’s stock options, the expected dividend yield and the fair value of the Company’s common stock on the measurement date. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards.

Income Taxes

The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the condensed consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the condensed consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date.

The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

Pursuant to the Internal Revenue Code of 1986, as amended (IRC), specifically Sections 382 and 383, the Company’s ability to use tax attribute carryforwards to offset future taxable income is limited if the Company experiences a cumulative change in ownership of more than 50% within athree-year testing period. The Company completed an ownership change analysis through December 31, 2024 pursuant to IRC Section 382 and determined that the Company’s ability to offset taxable income in 2024 is not expected to be impacted by ownership changes occurring prior to that date. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of remaining tax attribute carryforwards available to offset future taxable income and income tax expense in future years may be significantly restricted or eliminated. Further, the Company’s deferred tax assets associated with such tax attributes could be significantly reduced or eliminated upon realization of an ownership change within the meaning of IRC Section 382. If eliminated, the related asset would be removed from the deferred tax asset schedule, with a corresponding reduction in the valuation allowance. Additionally, limitations on the utilization of the Company’s tax attribute carryforwards can increase the amount of taxable income and current income tax expense recognized. Due to the existence of the valuation allowance, ownership change limitations that are not significant may not impact the Company's effective tax rate.

The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.

Net Loss per Share

Basic and diluted net loss per share is determined by dividing the net loss by the weighted-average number of common shares outstanding for the period. For all periods presented, the Company’s potentially dilutive securities include outstanding options under the Company’s 2018 Equity Incentive Plan, 2024 Inducement Plan and outstanding warrants to purchase common stock, each of which have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. Pre-funded warrants to purchase 30,816,705 shares of common stock are included in the computation of basic and diluted net loss per share for the three and nine months ended September 30, 2025, as the pre-funded warrants are exercisable for nominal consideration. There were no pre-funded warrants to purchase common stock in the three and nine months ended September 30, 2024. For all periods presented, there is no difference in the number of shares of common stock or common stock equivalents used to calculate basic and diluted shares outstanding due to the Company’s net loss position.

Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares):

3. Fair Value of Financial Instruments

The following tables summarize the Company’s assets that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands):

(a) Money Market funds included in cash and cash equivalents in the condensed consolidated balance sheets, are valued at quoted market prices in active markets.

(b) U.S. treasury securities included in short-term investments in the condensed consolidated balance sheets, are recorded at fair market value, which is determined based on the most recent observable inputs for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable.

The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities.

The Company didnot hold any Level 1, 2 or 3 financial liabilities that are recorded at fair value on a recurring basis as of September 30, 2025 or December 31, 2024.

4. Certain Financial Statement Caption Information

Short-Term Investments

The following table summarizes the Company’s short-term investments (in thousands):

The Company doesnot have any available-for-sale securities as of September 30, 2025. All of the Company’s available-for-sale securities are available to the Company for use in its current operations. As a result, the Company categorizes all of these securities as current assets.

There wereno impairments considered other-than-temporary during the periods presented, as it is management’s intention and ability to hold the securities until a recovery of the cost basis or recovery of fair value. Unrealized gains and losses are included in accumulated other comprehensive income.

Accrued Expenses

Accrued expenses consisted of the following (in thousands):

5. Segment Reporting

The Company operates through asingle operating and reportable segment focused on the business of developing novel therapeutics to treat immuno-inflammatory disorders with high unmet medical need. The Company manages all business activities on a consolidated basis. The Company’s chief operating decision maker (CODM) is the Chief Executive Officer.

The accounting policies of the operating segment are the same as those described in Note 2, Summary of Significant Accounting Policies. The CODM evaluates the performance of the operating segment and allocates resources based on net loss that also is reported on the condensed consolidated statements of operations and comprehensive loss as net loss. The measure of the operating segment assets is reported on the condensed consolidated balance sheets as total assets.

The CODM uses net loss to monitor budget versus actual results and to analyze cash flows in assessing performance of the segment and allocating resources. The significant expense categories regularly provided to the CODM include research and development and general and administrative expenses. These expense categories are reported as separate line items in our condensed consolidated statements of operations and comprehensive loss. All our revenue is attributable to the United States and to our single operating segment.

6. Leases

In September 2025, the Company entered into a non-cancelable operating lease for laboratory space in San Diego, California which expires in January 2028. Upon lease commencement, the Company recognized a right-of-use asset and a corresponding lease liability of$0.5 million. The Company's lease for laboratory space in La Jolla, California expired in August 2025 and the Company did not renew that lease. The Company also leases office space located in La Jolla that expires in February 2027.

The terms of the Company’s non-cancelable operating lease arrangements typically contain fixed lease payments which increase over the term of the lease at fixed rates and include rent holidays and provide for additional renewal periods. Lease expense is recognized over the term of the lease on a straight-line basis. All of the Company’s leases are classified as operating leases. The Company has determined that periods covered by options to extend the Company’s leases are excluded from the lease term as the Company is not reasonably certain the Company will exercise such options. Operating lease expense, including expenses related to short-term leases, was $0.2 million and $0.1 million for the three months ended September 30, 2025 and 2024, respectively. Operating lease expense, including expenses related to short-term leases, was $0.4 million for each of the nine months ended September 30, 2025 and 2024.

Under the lease arrangements, the Company may be required to pay directly, or reimburse the lessor for real estate taxes, insurance, utilities, maintenance and other operating costs. Such amounts are variable and therefore not included in the measurement of the right-of-use assets and related lease liability but are instead recognized as variable lease expense in the Company's condensed consolidated statements of operations when they are incurred. Variable lease expense, including expenses related to short-term leases, was $0.1 million for each of the three months ended September 30, 2025 and 2024. Variable lease expense, including expenses related to short-term leases, was $0.2 million for each of the nine months ended September 30, 2025 and 2024, respectively.

The Company records its right-of-use (ROU) assets within other assets (long term) and its operating lease liabilities within other current and long-term liabilities.

Additional information related to the Company’s leases as of and for the nine months ended September 30, 2025 and 2024, respectively, is as follows (in thousands, except lease term and discount rate):

As of September 30, 2025, the Company does not have any leases that have not yet commenced that create significant rights and obligations.

7. Partnerships

Asset Purchase Agreement with Ono Pharmaceutical Co., Ltd.

On December 5, 2022, the Company and Ono, a Japan kabushiki kaisha, entered into an Asset Purchase Agreement pursuant to which the Company granted Ono the exclusive right, but not the obligation, to acquire the Company’s rights to itolizumab (the Option). These rights included all therapeutic indications and the rights to commercialize itolizumab in the United States, Canada, Australia, and New Zealand. In exchange for the Option, Ono paid the Company a one-time, upfront payment of an amount equal to JPY 3.5 billion, or $26.4 million.

The Company was responsible for conducting all research and development of itolizumab, which had been funded by Ono from July 1, 2022 through October 30, 2024, the end of the option period. On October 30, 2024, the option period expired and the Asset Purchase Agreement automatically terminated pursuant to its terms.

During the three and nine months ended September 30, 2025, there wasno revenue recognized under the Asset Purchase Agreement. During the three and nine months ended September 30, 2024, the Company recognized revenue of $12.2 and $36.7 million, respectively, under the Asset Purchase Agreement. Such revenue was comprised of $8.1 million and $25.2 million associated with development funding for the three and nine months ended September 30, 2024, respectively, and $4.1 million and $11.5 million associated with the amortization of the upfront payment for the three and nine months ended September 30, 2024, respectively.

Termination of Biocon Collaboration and License Agreement

On September 30, 2025 (the Termination Date), the Company entered into a termination agreement with Biocon Limited (Biocon and the agreement, the Termination Agreement) pursuant to which the Company and Biocon terminated the License Agreement, the Memorandum of Understanding dated April 7, 2022 and certain other corresponding agreements (collectively Biocon Agreements), with all licenses granted by Biocon to the Company under the Biocon Agreements, including with respect to itolizumab, terminating and reverting to Biocon. See Note 10 for additional details regarding the Biocon Agreements. As consideration for certain technical servicesthe Company is obligated to provide to Biocon following the Termination Date, Biocon agreed to pay the Company a technical service fee of $363,000. In lieu of Biocon paying the technical service fee to the Company, Biocon will set off amounts owed by the Company to Biocon under or in connection with the Biocon Agreements through the Termination Date, with the amount of such set-off to equal such technical service fee, plus any other amount that has been or may be invoiced by the Company to Biocon for work performed by the Company with respect to itolizumab through the Termination Date, and to be limited to the aggregate amounts that have been or may be invoiced by Biocon to the Company, or are or may be otherwise owed by the Company to Biocon, under or in connection with the Biocon Agreements through the Termination Date. The Company has not yet recorded the technical service fee in its condensed consolidated financial statements as the services have not yet been completed as of September 30, 2025.

8. Stockholders’ Equity

Securities Purchase Agreement

On August 10, 2025, the Company entered into a Securities Purchase Agreement (the Purchase Agreement) with certain institutional and accredited investors (the Investors), pursuant to which the Company agreed to sell and issue shares (Shares) of the Company’s common stock and pre-funded warrants to purchase shares of common stock (Warrant Shares), in up to two closings in a private placement transaction (the Private Placement).

The initial closing of the Private Placement occurred on August 12, 2025, (the Initial Closing). At the Initial Closing, the Company issued and sold 21,814,874 Shares at a purchase price of $0.57 per share (the Share Price) and pre-funded warrants to purchase up to 30,816,705 Warrant Shares at a purchase price of $0.5699 per Warrant Share (the Warrant Price) to the Investors for gross proceeds to the Company of approximately $30.0 million. Net proceeds from the Private Placement were $27.9 million, after deducting placement agent fees and offering expenses totaling $2.1 million.

Pursuant to the Purchase Agreement, subject to the occurrence of the Milestone Closing Trigger (defined below), the Investors have agreed to purchase at a closing (the Milestone Closing) up to 35,087,717 Shares or pre-funded warrants in lieu thereof at a purchase price per Share and pre-funded warrant equal to the Share Price and the Warrant Price, respectively, for gross proceeds to the Company of up to approximately $20.0 million. The Milestone Closing trigger means: (A) the achievement of either of the following prior to the five-year anniversary of the date of the Purchase Agreement (i) the clearance of an investigational new drug application for EQ504 or (ii) the dosing of the first patient in a single ascending dose or a multiple ascending dose trial of EQ504 in Australia or New Zealand (the first such event to occur, the Milestone Event), and (B) (x) the achievement of a volume weighted average price per share of $2.50 (subject to appropriate, proportional adjustment for any stock splits or combinations of the common stock occurring after the date of the Purchase Agreement) measured during any 10 consecutive trading days during the 30 trading days following the date the Company first announces via a press release or Current Report on Form 8-K the occurrence of the Milestone Event (such period the Measurement Period and such price threshold requirement, the Price Threshold), or (y) the Company’s receipt of a waiver of the Price Threshold signed by the Investors who hold a majority of the securities issued in the Private Placement (determined as if all of the Warrant Shares underlying pre-funded warrants then outstanding have been issued without regard to any limitations on the exercise of such pre-funded warrants) and delivered to the Company during the Measurement Period (the achievement or occurrence of (A) and (B) are collectively, the Milestone Closing Trigger). In the event the Milestone Closing Trigger occurs as a result of a Price Threshold Waiver, only the waiving Investors will be obligated to purchase Shares or pre-funded warrants at the Milestone Closing.

The pre-funded warrants have an exercise price of $0.0001 per Warrant Share, subject to customary adjustments, and are exercisable at any time and will not expire until exercised in full. The pre-funded warrants will also be exercisable on a net exercise “cashless” basis. The pre-funded warrants may not be exercised if the aggregate number of shares of common stock beneficially owned by the holder thereof immediately following such exercise would exceed a specified beneficial ownership limitation, not to exceed 19.99%.

The Company assessed the 30,816,705 pre-funded warrants issued at the Initial Closing and the 35,087,717 Shares or pre-funded warrants in lieu thereof to be issued at the Milestone Closing subject to the occurrence of the Milestone Closing Trigger and determined that they do not require liability classification pursuant to ASC 480. The pre-funded warrants at the Initial Closing and the Shares or pre-funded warrants contingent to be issued at the Milestone Closing do not have any net cash settlement provisions that would preclude equity classification under ASC 815-40. Accordingly, the pre-funded warrants were recorded to additional paid-in capital in the condensed consolidated balance sheets. As of September 30, 2025 and through the date of the filing of this Quarterly Report on Form 10-Q, the pre-funded warrants issued at the Initial Closing have not been exercised.

Registration Rights Agreement

In connection with the Private Placement, the Company entered into a Registration Rights Agreement (the Registration Rights Agreement) with the Investors at the Initial Closing, pursuant to which the Company agreed to prepare and file, within 30 days of the Initial Closing and, if applicable, the Milestone Closing, subject to certain allowable delays, one or more registration statements with the SEC to register for resale the Shares and, as applicable, the Warrant Shares, in each case that were issued under the Purchase

Agreement, and generally to cause the applicable registration statements to promptly become effective. Certain cash penalties will apply to the Company in the event of registration failures.

On September 9, 2025, the Company filed a registration statement on Form S-3 (File No. 333-290138) for the resale of the Shares as well as the shares of common stock issuable upon the exercise of the pre-funded warrants that were issued at the Initial Closing, and it was declared effective on September 18, 2025.

2023 ATM Facility

In October 2023, the Company entered into an at-the-market facility with Jefferies LLC (Jefferies) under which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $21.95 million from time to time through Jefferies acting as the Company's sales agent (the 2023 ATM Facility). There wereno shares sold under the 2023 ATM Facility from October 2023 through December 31, 2024. In March 2025, there were 109,410 shares of common stock sold under the 2023 ATM Facility for gross proceeds of $55,000. Issuance costs related to the 2023 ATM Facility totaled $0.5 million through March 31, 2025.

On August 3, 2025, the Company entered into Amendment No. 1 to the 2023 ATM Facility pursuant to which Jefferies was replaced by LifeSci Capital LLC as the sales agent under the 2023 ATM Facility. During the three months ended September 30, 2025, there were 1,610,075 shares of common stock sold under the 2023 ATM Facility, as amended, for gross proceeds of approximately $0.9 million and net proceeds totaling $0.7 million, after deducting for issuance costs of $0.2 million. During the nine months ended September 30, 2025, there were 1,719,485 shares of common stock sold under the 2023 ATM Facility for gross proceeds of $1.0 million and net proceeds totaling $0.3 million, after deducting for issuance costs incurred inception-to-date of $0.7 million.

On September 19, 2025, the Company filed a prospectus supplement with the SEC under which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $75.0 million, pursuant to the 2023 ATM Facility, as amended.

As of September 30, 2025 and through the date of the filing of this Quarterly Report on Form 10-Q, there were no additional shares sold under the 2023 ATM Facility, as amended.

Stock Options

The following table summarizes stock option activity during the nine months ended September 30, 2025:

(a)

Aggregate intrinsic value in this table was calculated as the positive difference, if any, between the closing price per share of the Company’s common stock on September 30, 2025 of $1.43 and the price of the underlying options.

At September 30, 2025, unamortized stock compensation for stock options was $8.4 million, with a weighted-average recognition period of 3.73 years.

Stock-Based Compensation Expense

The non-cash stock-based compensation expense for all stock awards, net of forfeitures recognized as they occur, that was recognized in the condensed consolidated statements of operations is as follows (in thousands):

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance is as follows:

9. Income Taxes

The Company is subject to income tax in the United States (U.S.) as well as other tax jurisdictions in which it conducts business. Earnings from non-U.S. activities are subject to local country income tax. The Company does not provide for U.S. deferred income taxes on the undistributed earnings of its foreign subsidiaries as such earnings are reinvested indefinitely.

The Company’s tax provision for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual tax rate changes, the Company makes a cumulative adjustment in that quarter. The Company’s quarterly tax provision, and its quarterly estimate of its annual effective tax rate, are subject to significant volatility due to several factors, including the Company’s ability to accurately predict its pre-tax income and loss in multiple jurisdictions.

There wasno income tax expense recorded for the three and nine months ended September 30, 2025 and 2024, respectively. The Company does not record a deferred tax provision as there is a full valuation allowance offsetting the Company’s net deferred tax assets.

10. Related Party Transactions

On April 7, 2022, the Company entered into an agreement with Biocon, who was a holder of more than 5% of the Company's common stock, to collaborate on and co-fund a Phase 2 clinical study of itolizumab in subjects with ulcerative colitis that was being conducted by Biocon in India. The Company's share of the total clinical study costs was approximately $1.4 million. During the three and nine months ended September 30, 2025, the Company recognized $39,000 and $43,000 of research and development expenses related to its portion of the total clinical study costs, respectively. During the three and nine months ended September 30, 2024, the Company recognized $15,000 and $0.4 million of research and development expenses related to its portion of the total clinical study costs, respectively. As of September 30, 2025 and December 31, 2024, the Company had accrued expenses totaling $0.1 million and $0.2 million, respectively, and $0.1 million and $25,000, respectively, was invoiced by and payable to Biocon related to the Company's portion of the total clinical study costs.

In February 2020, the Company entered into a master services agreement with Syngene International Limited (Syngene), a wholly-owned subsidiary of Biocon, for chemistry, manufacturing and controls (CMC) services associated with itolizumab development (the Syngene MSA). In July 2023, the Company issued a signed work order under the Syngene MSA totaling $5.4 million for CMC activities. The Company stopped the majority of the work related to this work order in the third quarter of 2024. In addition, the Company entered into a work order for stability studies with Syngene in September 2024 totaling $0.1 million, which was completed as of September 30, 2025. In 2024, the Company entered into purchase orders for CMC projects and purchases of drug product with Biocon totaling approximately $6.5 million. As of October 30, 2024, the Company paused the majority of work related to those CMC projects. During the three and nine months ended September 30, 2025, the Company recognized research and development expenses totaling $20,000 and $0.1 million, respectively, related to the Biocon and Syngene CMC agreements. During the three and nine months ended September 30, 2024, the Company recognized research and development expenses totaling $1.0 million and $3.1 million, respectively, related to the Biocon and Syngene CMC agreements. As of September 30, 2025 and December 31, 2024, the Company had accrued expenses totaling $0.1 million and $43,000, respectively, and $0.1 million and $0.6 million, respectively, was invoiced by and payable to Biocon and Syngene.

On September 30, 2025, the Company entered into a Termination Agreement with Biocon with all licenses granted by Biocon to the Company under the Biocon Agreements, including with respect to itolizumab, terminating and reverting to Biocon. Refer to Note 7 for additional details.

The majority of the aforementioned expenses incurred through September 30, 2024 associated with work performed by Biocon or its affiliates related to itolizumab development were reimbursed by Ono pursuant to the terms of the Asset Purchase Agreement during the Ono option period which expired on October 30, 2024.

The Company classifies its accruals related to these activities as accrued expenses on the accompanying condensed consolidated balance sheets. The Company classifies amounts invoiced by and payable to Biocon and Syngene as accounts payable on the accompanying condensed consolidated balance sheets.