ENTA US Equity☆

ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

You should read the following discussion and analysis of financial condition and results of operations together with our consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K. This discussion and other parts of this Annual Report on Form 10-K contain forward-looking statements that involve risks and uncertainties, such as statements regarding our plans, objectives, expectations, intentions, and projections. Our actual results could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the “Risk Factors” section of this Annual Report on Form 10-K.

Overview

We are a biotechnology company that uses our robust, chemistry-driven approach and drug discovery capabilities to discover and develop small molecule drugs for virology and immunology indications.

Virology

We discovered glecaprevir, the second of two antiviral protease inhibitors developed through our collaboration with AbbVie for the treatment of acute or chronic infection with hepatitis C virus, or HCV. Glecaprevir is co-formulated as part of AbbVie’s leading brand of direct-acting antiviral, or DAA, combination treatment for HCV, which has been marketed under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir) since 2017 for the treatment of chronic HCV. MAVYRET® was also approved as the first and only treatment for acute HCV infection in June 2025.

Our active development programs in virology are focused on respiratory syncytial virus, or RSV, the most common cause of bronchiolitis and pneumonia and a leading cause of U.S. hospitalization in young children and a significant cause of respiratory illness in older adults. Populations at high risk for severe RSV infection include infants and young children, adults older than 65 years of age, and those with comorbidities such as chronic heart or lung disease. Recent CDC estimates suggest a significant RSV burden in the U.S., with up to 6.5 million outpatient visits, 350,000 hospitalizations and 23,000 deaths annually.

We also have clinical stage programs in virology for SARS-CoV-2, the virus that causes COVID-19, and Hepatitis B virus, or HBV, the most prevalent chronic hepatitis.

Immunology

In immunology, we are designing and developing highly potent and selective oral small molecule inhibitors for the treatment of type 2 inflammatory disease by targeting key mechanisms of the immune response. An overactive response is a primary driver of a number of inflammatory diseases.

Our initial immunology targets involve the following mechanisms of immune response:

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The receptor tyrosine kinase, known as KIT, which is critical for regulating mast cell survival and activation, including release of potent inflammatory mediators such as histamine, which is a primary driver of inflammation in the skin and implicated in multiple allergic diseases; and

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STAT6, a transcription factor uniquely responsible for interleukin-4, or (IL-4)/interleukin-13, or (IL-13) cell signaling, which drives a type 2 dominant phenotype and downstream inflammation.

These mechanisms are implicated, along with others, in several diseases, and it is not uncommon for an efficacious treatment for one disease to be tested and approved for other immunology indications. We currently plan to focus our initial immunology drug development proof-of-concept efforts on the following disease indications:

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Chronic spontaneous urticaria, or CSU, a severely debilitating, chronic inflammatory skin disease manifested by hives, angioedema, which is swelling of soft tissues, or both, but with no identified triggers, which has an estimated global prevalence of between 0.5% – 1% of the population, resulting in approximately 1.75 - 3.5 million people with this condition at any given time in the U.S. alone or chronic inducible urticaria (CIndU) of various forms with a variety of known triggers; and

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Atopic dermatitis, or AD, a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin with significant quality of life impacts such as leading a limited lifestyle, avoidance of social interactions and a reduced range of activities, with AD affecting 7.3% of the US adult population, of whom ~40% have moderate to severe disease.

As of September 30, 2025, we had $188.9 million in cash, cash equivalents and short-term marketable securities. Based on our operating plan, we believe that our existing cash, cash equivalents and short-term marketable securities as of September

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30, 2025, as well as the cash flows from our retained portion of future HCV royalties and the proceeds from our public offering in October 2025, will enable us to fund our operating expenses and capital expenditure requirements into fiscal 2029.

Our Royalty Revenue Collaboration and Royalty Sale Agreement

Our royalty revenue is generated through our Collaborative Development and License Agreement with AbbVie, under which we have discovered and out-licensed to AbbVie two protease inhibitor compounds that have been clinically tested, manufactured, and commercialized by AbbVie as part of its combination regimens for HCV.

Glecaprevir is the HCV protease inhibitor we discovered that was developed by AbbVie in a fixed-dose combination with its NS5A inhibitor, pibrentasvir, for the treatment of chronic HCV. In June 2025 it was also approved by the FDA as the first and only treatment for acute HCV infection. This patented combination, currently marketed under the brand names MAVYRET® (U.S.) and MAVIRET® (ex-U.S.), is referred to in this report as MAVYRET/MAVIRET. The first protease inhibitor developed through this collaboration, paritaprevir, is part of AbbVie’s initial HCV regimens, which have been almost entirely replaced by MAVYRET/MAVIRET. Since August 2017, substantially all of our royalty revenue has been derived from AbbVie’s net sales of MAVYRET/MAVIRET. Our ongoing royalty revenues from this regimen consist of annually tiered, double-digit, per-product royalties on 50% of the calendar year net sales of the glecaprevir/pibrentasvir combination in MAVYRET/MAVIRET. The annual royalty tiers return to the lowest tier for sales on and after each January 1.

In April 2023, we entered into a royalty sale agreement with an affiliate of OMERS, a Canadian public employee pension fund, pursuant to which we were paid a $200.0 million cash purchase price in exchange for 54.5% of our future quarterly royalty payments on net sales of MAVYRET/MAVIRET, after June 30, 2023, through June 30, 2032, subject to a cap on aggregate payments to OMERS equal to 1.42 times the purchase price.

For accounting purposes, we continue to record 100% of HCV royalties earned under the AbbVie agreement as royalty revenue in our consolidated statements of operations. The $200.0 million received in April 2023 was recognized on our consolidated balance sheets as a liability, which will be reduced by the payments made to OMERS over the term of the Agreement. We recognize imputed interest expense over the life of the royalty sale agreement based on our estimated future MAVYRET/MAVIRET royalties.

Financial Operations Overview

We are currently funding all research and development for our wholly-owned programs, which are targeted toward the discovery and development of novel compounds. We completed two Phase 2b studies of zelicapavir and a Phase 2a human challenge study of EDP-323, both of which are in our virology program. We also are conducting preclinical discovery research efforts in immunology.

As a result of the timing of our clinical and preclinical development programs, we expect our research and development expenses will fluctuate from period to period. However, in the next 12 months, we expect our external research and development expenses generally to decrease since we have completed our Phase 2 studies of zelicapavir and EDP-323 and we are evaluating partnering opportunities for the RSV programs.

Through September 30, 2025, we have funded our operations primarily through royalty payments received under our collaboration agreement with AbbVie, a $200.0 million payment received in April 2023 from our royalty sale agreement, and our existing cash, cash equivalents, and short-term marketable securities. Based on our operating plan, we believe that our existing cash, cash equivalents and short-term marketable securities as of September 30, 2025, as well as the cash flows from our retained portion of future HCV royalties and the proceeds from our public offering in October 2025, will enable us to fund our operating expenses and capital expenditure requirements into fiscal 2029.

Revenue

Our revenue is primarily derived from our collaboration agreement with AbbVie and AbbVie’s sales of MAVYRET/MAVIRET, an 8-week treatment regimen for acute or chronic HCV. During the year ended September 30, 2023, we also generated $1.0 million of license revenue from an upfront payment related to a license agreement for one of the antibacterial compounds we are no longer developing.

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The following table is a summary of revenue recognized for the years ended September 30, 2025, 2024, and 2023:

Years Ended September 30,

(in thousands)

Revenue

License revenue — — 1,000

As disclosed above regarding our OMERS royalty sale agreement, we only retain 45.5% of the cash payments from royalties on net sales of MAVYRET/MAVIRET occurring after June 30, 2023 through June 30, 2032, subject to a cap on aggregate payments to OMERS equal to 1.42 times OMERS’ purchase price.

Internal Programs

As our internal product candidates are currently in Phase 1 or Phase 2 clinical development, we have not generated any revenue from our own product sales. We do not expect to generate any revenue from product sales derived from these product candidates for at least the next several years.

Operating Expenses

Our operating expenses are comprised of research and development expenses and general and administrative expenses.

Research and Development Expenses

Research and development expenses consist of costs incurred to conduct basic research, such as the discovery and development of novel small molecules as therapeutics, as well as any external expenses of preclinical and clinical development activities. We expense all costs of research and development as incurred. These expenses consist primarily of:

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third-party contract costs relating to research, formulation, manufacturing, preclinical study, and clinical trial activities;

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personnel costs, including salaries, related benefits, and stock-based compensation for employees engaged in scientific research and development functions;

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allocated facility-related costs;

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laboratory consumables; and

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third-party license fees.

At any given time, we have later stage programs in clinical development as well as several active early-stage research and drug discovery projects. Our internal resources, employees and infrastructure are utilized across multiple projects, including our early-stage discovery projects. As such, we report information regarding costs incurred based on our programs (i.e., disease area) rather than on a project specific basis. All indirect costs are allocated to programs based on headcount and square footage of our facilities. We expect that our research and development expenses will fluctuate from period to period as we advance our research and development programs. However, in the next 12 months, we expect our external research and development expenses generally to decrease since we have completed our Phase 2 studies of zelicapavir and EDP-323 and we are evaluating partnering opportunities for the RSV programs. To date, we have not identified any significant impact of inflation on spending in research and development, but it is uncertain whether there will be inflationary impacts in future periods.

Our research and drug discovery and development programs are in early stages; therefore, the successful development of our product candidates is highly uncertain and may not result in approved products. Completion dates and completion costs can vary significantly for each product candidate and are difficult to predict. Given the uncertainty associated with clinical trial enrollments and the risks inherent in the development process, we are unable to determine the duration and completion costs of the current or future clinical trials of our product candidates or if, or to what extent, we will generate revenue from the commercialization and sale of any of our product candidates. We anticipate that we will make determinations as to which development programs to pursue and how much funding to direct to each program on an ongoing basis in response to the preclinical and clinical success and prospects of each product candidate, as well as ongoing assessments of the commercial potential of each product candidate.

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General and Administrative Expenses

General and administrative expenses consist primarily of personnel costs, which include salaries, related benefits and stock-based compensation, of our executive, finance, business and corporate development and other administrative functions. General and administrative expenses also include allocated facility-related costs not otherwise included in research and development expenses, directors’ and officers’ liability insurance premiums, professional fees for auditing, tax, and legal services, patent expenses and litigation expenses associated with prosecuting our patent infringement litigation.

We expect that general and administrative expenses may increase in the long term. To date we have not experienced a significant impact of inflation on general and administrative expenses.

Other Income (Expense)

Other income (expense) consists of interest expense, interest and investment income, net and the change in fair value of our outstanding Series 1 nonconvertible preferred stock. Interest expense consists of the interest expense and amortization of debt issuance costs associated with the royalty sale agreement with an affiliate of OMERS. Interest income consists of interest earned on our cash equivalents and marketable securities balances. Investment income consists of the amortization or accretion of any purchased premium or discount, respectively, on our marketable securities. The change in fair value of our Series 1 nonconvertible preferred stock relates to the remeasurement of these financial instruments from period to period as these instruments may require a transfer of assets because of the liquidation preference features of the underlying instrument.

Income Tax Benefit (Expense)

Income tax benefit (expense) is based on our best estimate of taxable net income (loss), applicable income tax rates, net research and development tax credits and carryforwards, net operating loss carrybacks and interest earned on such refunds, changes in valuation allowance estimates and deferred income taxes.

On July 4, 2025, the U.S. government enacted the One Big Beautiful Bill Act ("OBBBA"), which includes several changes to U.S. federal income tax law, including the temporary and permanent extension of expiring provisions of the Tax Cuts and Jobs Act of 2017. We determined that the tax provisions of the legislation do not have a material impact on our 2025 consolidated financial statements and continue to assess the impact on future years.

Critical Accounting Policies

Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amount of assets, liabilities, equity, revenue, costs and expenses, and related disclosures. We believe that the estimates and assumptions involved in the accounting policies described below may have the greatest potential impact on our consolidated financial statements and, therefore, consider these to be our critical accounting policies. We evaluate our estimates and assumptions on an ongoing basis. Actual results may differ from these estimates under different assumptions and conditions. See also Note 2 to the consolidated financial statements included elsewhere in this Annual Report on Form 10-K for information about these critical accounting policies as well as a description of our other significant accounting policies.

Research and Development and Pharmaceutical Drug Manufacturing Accruals

We have entered into various contracts with third parties to perform research and development and pharmaceutical drug manufacturing. These include contracts with contract research organizations, or CROs, clinical manufacturing organizations, or CMOs, testing laboratories, research hospitals and not-for-profit organizations and other entities to support our research and development activities. We expense the cost of each contract as the work is performed. When billing terms under these contracts do not coincide with the timing of when the work is performed, we are required to make estimates of our outstanding obligations to those third parties as of period-end. Our accrual estimates are based on a number of factors, including our knowledge of the research and development programs and pharmaceutical drug manufacturing activities and associated timelines, invoicing to date, and the provisions in the contract. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from our estimates.

Liability Related to the Sale of Future Royalties

We accounted for the $200.0 million payment from OMERS as a liability on our consolidated balance sheets because (1) under the royalty sale agreement, OMERS will receive a portion of our royalty payments up to a capped amount of 1.42 times the original payment to us, and (2) we have significant continuing involvement in the generation of cash flows under the AbbVie Agreement. Interest expense for the liability related to the sale of future royalties will be recognized using the effective interest rate method over the term of the royalty sale agreement.

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The liability related to the sale of future royalties and the related interest expense are based on our current estimates of future royalties, which we determine by using third-party forecasts of MAVYRET/MAVIRET sales. Third-party forecasts are updated periodically based on the latest pricing, market share, and patient data. Changes in the amount or timing of estimated royalties will affect the interest rate utilized in calculating the liability related to the sale of future royalties.

Results of Operations

Years Ended September 30,

(in thousands)

Change in fair value of Series 1 nonconvertible preferred stock 39 73 —

Comparison of the Years Ended September 30, 2025 and 2024

Revenue

We recognized revenue of $65.3 million and $67.6 million during the years ended September 30, 2025 and 2024, respectively. The decrease in revenue year-over-year was primarily due to AbbVie’s lower reported HCV sales as compared to the comparable period in 2024.

Our royalty revenues eligible to be earned in the future will depend on AbbVie’s HCV market share, the pricing of the MAVYRET/MAVIRET regimen, the number of patients treated and the effect of the label expansion for MAVYRET in the United States for the treatment of patients with acute HCV. In addition, at the beginning of each calendar year (the second quarter of our fiscal year), our royalty rate resets to the lowest tier for each of our royalty-bearing products licensed to AbbVie.

Beginning with the quarter ended September 30, 2023, 54.5% of our quarterly royalty payments on net sales of MAVYRET/MAVIRET that are included in our total revenue are paid to OMERS through June 30, 2032, subject to a cap on aggregate payments equal to 1.42 times the purchase price. The $200.0 million received in April 2023 was recognized on our consolidated balance sheets as a liability which will be reduced by the payments made to OMERS over the term of the royalty sale agreement. We will continue to record 100% of HCV royalties earned under the AbbVie Agreement as royalty revenue in our consolidated statements of operations since the AbbVie Agreement has not been amended and is independent of our agreement with OMERS.

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Research and development expenses

Years Ended September 30,

(in thousands)

R&D programs:

Virology

Immunology

Other Programs

Research and development expenses for the year ended September 30, 2025 decreased by $24.7 million compared to the same period in 2024.

Virology

The costs in our virology program decreased by $30.8 million primarily due to the timing of clinical trials in our RSV programs.

Immunology

The costs in our immunology programs increased by $10.2 million as we advance this new therapeutic area of focus for the company.

Other Programs

Other program costs decreased by $4.1 million due to the completion of the discovery-stage activities related to our STAT6 program.

General and administrative expenses

General and administrative expenses decreased by $13.9 million for the year ended September 30, 2025, compared to the same period in 2024, primarily due to a decrease in legal expenses related to our patent infringement suit against Pfizer and a decrease in stock-based compensation expenses.

Other income (expense)

Changes in components of other income (expense) were as follows:

Interest expense

Interest expense decreased by $3.3 million for the year ended September 30, 2025, as compared to the same period in 2024, due to the paydown of our obligation associated with our royalty sale agreement entered into during April 2023 with an affiliate of OMERS.

Interest and investment income, net

Interest and investment income, net, decreased by $5.3 million for the year ended September 30, 2025, as compared to the same period in 2024. The decrease was due to lower cash and investment balances year over year.

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Income tax benefit (expense)

During each of the years ended September 30, 2025 and 2024, we recorded an income tax benefit of $1.7 million, representing interest recorded on our $33.8 million federal tax refund, which we received in April 2025.

On July 4, 2025, the U.S. government enacted the One Big Beautiful Bill Act ("OBBBA"), which includes several changes to U.S. federal income tax law, including the temporary and permanent extension of expiring provisions of the Tax Cuts and Jobs Act of 2017. We determined that the tax provisions of the legislation do not have a material impact on our 2025 consolidated financial statements and continue to assess the impact on future years.

Comparison of the Years Ended September 30, 2024 and 2023

For a discussion of our results of operations for the year ended September 30, 2024, as compared to the year ended September 30, 2023, see Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Results of Operations—Comparison of the Years Ended September 30, 2024 and 2023 included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2024.

Liquidity and Capital Resources

We fund our operations with cash flows from our retained portion of our royalty revenue and our existing financial resources. At September 30, 2025, our principal sources of liquidity were cash and cash equivalents and short-term marketable securities of $188.9 million.

The following table shows a summary of our cash flows:

Years Ended September 30,

(in thousands)

Cash provided by (used in):

Net cash used in operating activities

Cash used in operating activities was $19.3 million for the year ended September 30, 2025 as compared to cash used in operating activities of $78.8 million for the same period in 2024. The decrease in cash used in operating activities of $59.5 million was primarily driven by lower operating expenses and receipt of a $33.8 million income tax refund in April 2025, partially offset by lower cash receipts associated with our AbbVie agreement.

Net cash provided by (used in) investing activities

Cash provided by investing activities was $40.3 million for the year ended September 30, 2025 as compared to cash provided by investing activities of $58.2 million for the same period in 2024. Our cash provided by investing activities decreased $17.9 million, driven by timing of purchases, sales and maturities of marketable securities in 2025 compared to 2024. This decrease was partially offset by a reduction in capital expenditures in fiscal 2025 as we completed the buildout of our new office and laboratory space at 4 Kingsbury Avenue in 2025.

Net cash (used in) provided by financing activities

Cash used in financing activities was $26.6 million for the year ended September 30, 2025 as compared to cash used in financing activities of $27.6 million for the same period in 2024. Our cash used in financing activities decreased $1.0 million, driven primarily by lower payments on our royalty sale agreement with OMERS.

Year Ended September 30, 2024

For a discussion of our cash flows for the year ended September 30, 2024, see Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Cash Flows included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2024.

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Funding Requirements

As of September 30, 2025, we had $188.9 million in cash, cash equivalents and short-term marketable securities. Based on our operating plan, we believe that our existing cash, cash equivalents and short-term marketable securities as of September 30, 2025, as well as the cash flows from our retained portion of future HCV royalties and the proceeds from our public offering in October 2025, will enable us to fund our operating expenses and capital expenditure requirements into fiscal 2029. However, our projection of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially.

Our future capital requirements are difficult to forecast and will depend on many factors, including:

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the number and characteristics of our research and development programs;

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the scope, progress, results and costs of researching and developing our product candidates on our own, including conducting advanced clinical trials;

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our ability to establish new collaborations, licensing or other arrangements, if any, and the financial terms of such arrangements;

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the amount of our retained portion of royalties generated from MAVYRET/MAVIRET sales under our existing collaboration with AbbVie;

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delays and additional expenses in our clinical trials;

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the cost of manufacturing our product candidates for clinical development and any products we successfully commercialize independently;

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opportunities to in-license or otherwise acquire new technologies and therapeutic candidates;

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costs associated with prosecuting our patent infringement litigation regarding use of a coronavirus 3CL protease inhibitor in Paxlovid, Pfizer's antiviral treatment for COVID-19;

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the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently;

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the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs;

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the timing and amount of any sales of our product candidates, if any, or royalties thereon;

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the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation; and

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potential fluctuations in foreign currency exchange rates.

Off-Balance Sheet Arrangements

We do not engage in any off-balance sheet financing activities. We do not have any interest in entities referred to as variable interest entities, which include special purpose entities and other structured finance entities.

Recently Issued Accounting Pronouncements

A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is set forth in Note 2 to the consolidated financial statements included in this Annual Report on Form 10-K.

Contractual Obligations and Commitments

Facility Leases

As of the date of this report, we lease space in Watertown, Massachusetts, under two separate lease agreements with one landlord.

In May 2022, we entered into a ten-year lease for new laboratory and office space in Watertown, Massachusetts, adjacent to our 400 Talcott Avenue premises at Arsenal on the Charles at 4 Kingsbury Avenue since our lease for office and laboratory space at 500 Arsenal Street was to expire on September 1, 2027. The construction of the facility shell was completed and we gained access to the building to construct tenant improvements during the three months ended March 31, 2024. Upon gaining access to the 4 Kingsbury Avenue building, we capitalized a right-of-use asset and lease liability of approximately $32 million on our consolidated balance sheets which reflects our fixed base rent payments, net of approximately $15 million of a

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tenant improvement allowance provided by the landlord, over the 10-year term of the lease. The 4 Kingsbury Avenue lease ends September 30, 2034.

In conjunction with the commencement of our lease at 4 Kingsbury Avenue during the three months ended March 31, 2024, we adjusted our 500 Arsenal Street lease liability to shorten the expiration date from September 2027 to the date the 4 Kingsbury Avenue building became ready for our occupancy. This resulted in a decrease in the lease liability and right-of-use asset on our consolidated balance sheets by approximately $9.0 million. The rent commencement date for our 4 Kingsbury Avenue lease was September 12, 2024, and we moved into the space in November 2024 at which time our lease at 500 Arsenal Street expired.

The second lease for office space located at 400 Talcott Avenue commenced on September 24, 2018 for a term of six years. In May 2022, we amended this lease to expand the rented space and extend the lease term through June 1, 2034. We spent approximately $6.3 million in capital expenditures for the additional space, which primarily relate to tenant improvements. We received a tenant improvement allowance from the landlord of $2.5 million. In July 2024, we amended our lease agreement to confirm alignment with the lease end date of our 4 Kingsbury Avenue lease at September 30, 2034.

Total estimated minimum lease payments for the next 5 years and thereafter under our existing facility and leased equipment agreements are $8.5 million in 2026, $8.7 million in 2027, $9.0 million in 2028, $9.3 million in 2029, $9.5 million in 2030, and $41.1 million thereafter.

Preferred Stock

As of September 30, 2025, we had 1.9 million outstanding shares of Series 1 nonconvertible preferred stock, all of which we classified as a long-term liability on our consolidated balance sheet and recorded at fair value of $1.3 million. The fair value of the preferred stock was measured based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The fair value of these instruments represents less than 10% of liabilities as of September 30, 2025. The Series 1 nonconvertible preferred stock issued would require the payment of $2.0 million in the event of a qualifying merger or sale of the company.

OMERS Agreement

In April 2023, we entered into a royalty sale agreement with an affiliate of OMERS, pursuant to which we were paid a $200.0 million cash purchase price in exchange for 54.5% of our future quarterly royalty payments on net sales of MAVYRET/MAVIRET after June 30, 2023, through June 30, 2032, subject to a cap on aggregate payments equal to 1.42 times the purchase price.

The $200.0 million received in April 2023 was recognized on our consolidated balance sheets as a liability which will be reduced by the payments made to OMERS over the term of the Agreement.

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Interest Rate Risk

We had cash, cash equivalents and short-term marketable securities of $188.9 million and $248.2 million at September 30, 2025 and 2024, respectively, which consisted of cash, money market funds, and treasury notes. Interest income is sensitive to changes in the general level of interest rates; however, due to the nature of these investments, a change in market interest rates of 1% would not be expected to have a material impact on our financial condition or results of operations for either period.

Foreign Exchange Risk

As we continue to progress our wholly-owned programs into clinical development, we will conduct clinical trials and clinical manufacturing outside of the U.S. and thus will face exposure to movements in foreign currency exchange rates, primarily the British Pound and Euro, against the U.S. Dollar, arising from our accounts payable and accrued expenses. During fiscal 2025 and 2024, the impact of foreign currency exposure was immaterial and thus did not have a significant impact on our consolidated financial statements. Our operations may become subject to more significant fluctuations in foreign currency exchange rates in the future if we continue to contract with vendors outside of the U.S.

ITEM 8. CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

Our consolidated financial statements, together with the report of our independent registered public accounting firm, appear on pages F-1 through F-26 of this Annual Report on Form 10-K.

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ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

None.

ITEM 9A. CONTROLS AND PROCEDURES

Disclosure Controls and Procedures and Internal Control over Financial Reporting

Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in the Company’s reports under the Securities Exchange Act of 1934, as amended, or the Exchange Act, is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to management, including our Chief Executive Officer (Principal Executive Officer, or "PEO") and Vice President, Finance (Principal Financial Officer or "PFO"), as appropriate, to allow timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognized that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, as the Company's are designed to do, and management necessarily was required to apply its judgment in evaluating the risk related to controls and procedures.

In connection with the preparation of this Form 10-K, as of September 30, 2025, an evaluation was performed under the supervision and with the participation of our management, including the PEO and PFO, of the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act). Based on that evaluation, our PEO and PFO concluded that our disclosure controls and procedures were effective at a reasonable assurance level as of September 30, 2025. These conclusions were communicated to the Audit Committee.

Management’s Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rule 13a-15(f) and Rule 15d-15(f) under the Exchange Act. Our internal control system is designed to provide reasonable assurance to the Company’s management and Board of Directors regarding the preparation and fair presentation of published financial statements. All internal control systems, no matter how well designed, have inherent limitations. Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to financial statement preparation and presentation.

Our management has assessed the effectiveness of our internal control over financial reporting as of September 30, 2025. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in its 2013 Internal Control—Integrated Framework. Based on this assessment, our management has concluded that as of September 30, 2025, our internal control over financial reporting is effective.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting that occurred during the quarter ended September 30, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

ITEM 9B. OTHER INFORMATION

During the fourth quarter ended September 30, 2025, none of our directors or officers (as defined in Rule 16a-1(f) of the Securities Exchange Act of 1934, as amended) adopted, modified, or terminated a Rule 10b5-1 trading arrangement.

ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS

Not applicable.

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PART III

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

Portions of the response to this item are incorporated herein by reference to the discussion responsive thereto in the Company’s Definitive Proxy Statement relating to the 2026 Annual Meeting of Stockholders, also referred to as the 2026 Proxy Statement, which will be filed within 120 days after September 30, 2025.

We have adopted a Code of Business Conduct and Ethics (the code of ethics) that applies to all of our employees, officers and directors. The code of ethics is available on our website at http://www.enanta.com. In addition, if we make any substantive amendments to the code of ethics or grant any waiver, including any implicit waiver, from a provision of the code to any of our executive officers or directors, we will disclose the nature of such amendment or waiver as required by applicable law on our website or on a Form 8-K.

ITEM 11. EXECUTIVE COMPENSATION

The response to this item is incorporated herein by reference from the discussion responsive thereto in the 2026 Proxy Statement, which will be filed within 120 days after September 30, 2025.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS

The response to this item is incorporated herein by reference in part from the discussion responsive thereto in the 2026 Proxy Statement, which will be filed within 120 days after September 30, 2025.

The following table provides information about the securities authorized for issuance under the Company’s equity compensation plans as of September 30, 2025:

Equity Compensation Plan Information

(in thousands, except per share information)

(a) (b) (c)

Equity compensation plans not approved by security holders — — —

(1)

Consists of the Company’s 2019 Equity Incentive Plan, the Company's 2024 Inducement Stock Plan, the Company’s 2012 Equity Incentive Plan, as amended, and the Company’s Employee Stock Purchase Plan.

(2)

Consists of shares of the Company’s common stock issuable upon exercise of outstanding options issued under the Company’s 2019 Equity Incentive Plan, the Company's 2024 Inducement Stock Plan and the Company’s Amended and Restated 2012 Equity Incentive Plan.

(3)

Consists of shares of the Company’s common stock reserved for future issuance under the Company’s 2019 Equity Incentive Plan, the Company's 2024 Inducement Stock Plan and the Company’s Employee Stock Purchase Plan.

70

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

The response to this item is incorporated herein by reference from the discussion responsive thereto in the 2026 Proxy Statement, which will be filed within 120 days after September 30, 2025.

ITEM 14. PRINCIPAL ACCOUNTING FEES AND SERVICES

The response to this item is incorporated herein by reference from the discussion responsive thereto in the 2026 Proxy Statement, which will be filed within 120 days after September 30, 2025.

71

PART IV

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

(a) 1. FINANCIAL STATEMENTS

The financial statements are included under Part II, Item 8 of this Report.

2. FINANCIAL STATEMENTS SCHEDULE

Schedules are omitted because they are not applicable, or are not required, or because the information is included in the consolidated financial statements and notes thereto.

3. EXHIBITS –

The exhibits are listed below under Part IV, Item 15(b) of this Report.

(b) EXHIBITS

Incorporated by Reference

72

73

21.1 Subsidiaries of the Company. X

101.SCH Inline XBRL Taxonomy Extension Schema with embedded Linkbases document

# Management contract or compensatory plan, contract or agreement.

† Confidential treatment granted as to portions of this Exhibit. The confidential portions of this Exhibit have been omitted and are marked by asterisks.

†† This Exhibit has been filed separately with the commission pursuant to an application for confidentiality treatment. The confidential portions of this Exhibit have been omitted and are marked by asterisks.

ITEM 16. FORM 10-K SUMMARY

None.

74

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Company has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized, this 19th day of November, 2025.

ENANTA PHARMACEUTICALS, INC.

By: /s/ Jay R. Luly, Ph.D.

Jay R. Luly, Ph.D.

Chief Executive Officer

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the Company in the capacities and on the dates indicated.

Signature Title Date

Kathleen S. Capps, CPA

/s/ Bruce L.A. Carter, Ph.D. Bruce L.A. Carter, Ph.D. Director November 19, 2025

/s/ Mark G. Foletta Mark G. Foletta Director November 19, 2025

/s/ Yujiro S. Hata Yujiro S. Hata Director November 19, 2025

/s/ Kristine Peterson Kristine Peterson Director November 19, 2025

/s/ Terry Vance Terry Vance Director November 19, 2025

75

ITEM 8. CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

ENANTA PHARMACEUTICALS, INC.

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Page

Report of Independent Registered Public Accounting Firm (PCAOB ID 238) F-2

Consolidated Balance Sheets F-4

Consolidated Statements of Operations F-5

Consolidated Statements of Comprehensive Loss F-6

Consolidated Statements of Stockholders’ Equity F-7

Consolidated Statements of Cash Flows F-8

Notes to Consolidated Financial Statements F-9

F-1

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Stockholders of Enanta Pharmaceuticals, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Enanta Pharmaceuticals, Inc. and its subsidiary (the "Company") as of September 30, 2025 and 2024, and the related consolidated statements of operations, of comprehensive loss, of stockholders’ equity and of cash flows for each of the three years in the period ended September 30, 2025, including the related notes (collectively referred to as the "consolidated financial statements"). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of September 30, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended September 30, 2025 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s consolidated financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these consolidated financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that (i) relates to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Research and Development and Pharmaceutical Drug Manufacturing Accruals

As described in Notes 2 and 6 to the consolidated financial statements, the Company has entered into various contracts with third parties to perform research and development and pharmaceutical drug manufacturing. When billing terms under these contracts do not coincide with the timing of when the work is performed, management is required to make estimates of outstanding obligations to those third parties as of period end. Within accrued expenses and other current liabilities, total accrued research and development expenses and accrued pharmaceutical drug manufacturing amounted to $1.8 million and $2.7 million as of September 30, 2025, respectively. The accrual estimates are based on a number of factors, including management’s knowledge of the research and development programs and pharmaceutical drug manufacturing activities and associated timelines, invoicing to date, and the provisions in the contract. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period.

F-2

The principal considerations for our determination that performing procedures relating to research and development and pharmaceutical drug manufacturing accruals is a critical audit matter are the significant judgment by management in developing the accrual estimates, as the estimates are based on a number of factors, including management’s knowledge of the research and development programs and pharmaceutical drug manufacturing activities and associated timelines, invoicing to date, and the provisions in the contracts, which in turn led to a high degree of auditor judgment, subjectivity and effort in performing procedures and evaluating management’s significant assumptions related to progress towards completion of the research and development programs and pharmaceutical drug manufacturing activities.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included, among others (i) testing management’s process for developing estimates based upon the progress of the research and development programs and pharmaceutical drug manufacturing activities; (ii) evaluating the appropriateness of the method used by management to develop the estimates; (iii) reading research and development and pharmaceutical drug manufacturing contracts on a test basis; (iv) evaluating the completeness and accuracy of data used by management; and (v) evaluating the reasonableness of significant assumptions related to the progress towards completion. Evaluating management’s assumptions related to progress towards completion of the research and development programs and pharmaceutical drug manufacturing activities included evaluating whether the assumptions were reasonable considering the associated timelines, invoicing to date and the provisions in the contracts.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

November 19, 2025

We have served as the Company’s auditor since 1999.

F-3

ENANTA PHARMACEUTICALS, INC.

CONSOLIDATED BALANCE SHEETS

(in thousands, except per share data)

September 30, September 30,

Assets

Current assets:

Prepaid expenses and other current assets 8,590 12,413

Income tax receivable — 31,999

Short-term restricted cash — 608

Other long-term assets 92 94

Liabilities and Stockholders' Equity

Current liabilities:

Accrued expenses and other current liabilities 12,751 13,547

Liability related to the sale of future royalties 30,710 34,462

Operating lease liabilities, net of current portion 54,757 53,943

Series 1 nonconvertible preferred stock 1,311 1,350

Other long-term liabilities 260 231

Commitments and contingencies (Note 13)

Stockholders' equity:

Accumulated other comprehensive (loss) gain (339 ) 302

Total liabilities and stockholders' equity $ 280,732 $ 376,652

The accompanying notes are an integral part of these consolidated financial statements.

F-4

ENANTA PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share data)

Years Ended September 30,

Revenue

License revenue — — 1,000

Operating expenses:

Other income (expense):

Change in fair value of Series 1 nonconvertible preferred stock 39 73 —

Net loss per share, basic and diluted $ (3.84 ) $ (5.48 ) $ (6.38 )

The accompanying notes are an integral part of these consolidated financial statements.

F-5

ENANTA PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS

(in thousands)

Years Ended September 30,

Other comprehensive (loss) income:

Net unrealized (loss) gain on marketable securities (641 ) 1,476 2,550

Total other comprehensive (loss) income (641 ) 1,476 2,550

The accompanying notes are an integral part of these consolidated financial statements.

F-6

ENANTA PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(in thousands)

Accumulated Retained

Additional Other Earnings Total

Common Stock Paid-In Comprehensive (Accumulated Stockholders'

Shares Amount Capital Income (Loss) Deficit) Equity

Stock-based compensation expense — — 28,216 — — 28,216

Other comprehensive income — — — 2,550 — 2,550

Exercise of stock options 16 — 147 — — 147

Vesting of restricted stock units, net of withholding 119 1 (295 ) — — (294 )

Stock-based compensation expense — — 26,795 — — 26,795

Other comprehensive income — — — 1,476 — 1,476

Exercise of stock options 16 — 145 — — 145

Vesting of restricted stock units, net of withholding 177 2 (279 ) — — (277 )

Stock-based compensation expense — — 18,565 — — 18,565

Other comprehensive loss — — — (641 ) — (641 )

The accompanying notes are an integral part of these consolidated financial statements.

F-7

ENANTA PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

Years Ended September 30,

Cash flows from operating activities

Adjustments to reconcile net loss to net cash used in operating activities:

Premium paid on marketable securities — — (73 )

Loss on disposal of property and equipment 6 16 150

Change in fair value of Series 1 nonconvertible preferred stock (39 ) (73 ) —

Change in operating assets and liabilities:

Prepaid expenses and other current assets 3,823 850 182

Other long-term liabilities 29 (432 ) 209

Cash flows from investing activities

Cash flows from financing activities

Proceeds from the exercise of stock options 145 147 2,208

Proceeds from the sale of future royalties — — 200,000

Payments for debt issuance costs — — (325 )

Payments for settlement of share-based awards (277 ) (294 ) (3,757 )

Supplemental disclosure of cash flow information

Cash received from tenant improvement allowances $ 5,881 $ 9,358 $ 1,994

Cash received from income tax refund $ 33,785 $ — $ —

Supplemental disclosure of non-cash information:

The accompanying notes are an integral part of these consolidated financial statements.

F-8

ENANTA PHARMACEUTICALS, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(Amounts in thousands, except per share data)

1. Nature of the Business

Enanta Pharmaceuticals, Inc. (collectively with its subsidiary, the “Company”), incorporated in Delaware in 1995, is a biotechnology company that uses its robust, chemistry-driven approach and drug discovery capabilities to discover and develop small molecule drugs with an emphasis on virology and immunology. The Company discovered glecaprevir, the second of two antiviral protease inhibitors discovered and developed through its collaboration with AbbVie for the treatment of chronic infection with hepatitis C virus, or HCV. Glecaprevir is co-formulated as part of AbbVie’s leading brand of direct-acting antiviral, or DAA, combination treatment for HCV, which has been marketed under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir) since 2017 for the treatment of chronic HCV. MAVYRET® was also approved as the first and only treatment for acute HCV infection in June 2025.

The Company is subject to many of the risks common to companies in the biotechnology industry, including but not limited to, the uncertainties of research and development, competition from technological innovations of others, dependence on collaborative arrangements, protection of proprietary technology, dependence on key personnel and compliance with government regulation. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approvals, prior to commercialization. These efforts require significant amounts of capital, adequate personnel and infrastructure, and extensive compliance reporting capabilities.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements include those of the Company and its subsidiary, Enanta Pharmaceuticals Security Corporation, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, management’s judgments with respect to its revenue arrangements; liability related to the sale of future royalties; valuation of stock-based awards and the accrual of research and development expenses. Estimates are periodically reviewed in light of changes in circumstances, facts and experience.

Cash Equivalents and Marketable Securities

The Company considers all short-term, highly liquid investments with original maturities of ninety days or less at acquisition date to be cash equivalents.Marketable securities with original maturities of greater than ninety days and remaining maturities of less than one year from the balance sheet date are classified as short-term marketable securities. Marketable securities with remaining maturities of greater than one year from the balance sheet date are classified as long-term marketable securities.

The Company classifies all of its marketable securities as available-for-sale. The Company continually evaluates the credit ratings of its investment portfolio and underlying securities. The Company invests in accordance with its investment policy and invests at the date of purchase in securities with a rating of A3/A- or higher according to Moody’s or S&P or A- by Fitch. The Company reports available-for-sale investments at fair value as of each balance sheet date and records any unrealized gains or losses as a component of stockholders’ equity. The cost of securities sold is determined on a specific identification basis and realized gains and losses are included in other income (expense) within the consolidated statements of operations. When the fair value is below the amortized cost of a marketable security, an estimate of expected credit losses is made. The credit-related impairment amount is recognized in the consolidated statements of operations. Credit losses are recognized through the use of an allowance for credit losses account in the consolidated balance sheet and subsequent improvements in expected credit losses are recognized as a reversal of an amount in the allowance account. If the Company has the intent to sell the security or it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis, then the allowance for the credit loss is written-off and the excess of the amortized cost basis of the asset over its fair value is recorded in the consolidated statements of operations. There were no credit losses recorded during the years ended September 30, 2025, 2024, and 2023.

F-9

Restricted Cash

As of September 30, 2025 and 2024, the Company had outstanding letters of credit collateralized by a money market account totaling $3,360 and $3,968 respectively, to the benefit of the landlord of the Company’s building leases. A total of $3,360 is classified as long-term restricted cash as of September 30, 2025. As of September 30, 2024, $608 was classified as short-term restricted cash and $3,360 was classified as long-term restricted cash based on the lease term end date of the Company's facility lease agreements

Concentration of Credit Risk and of Significant Customers and Suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, short-term and long-term marketable securities and accounts receivable. The Company has all cash and investment balances at one accredited financial institution, including cash in amounts that exceed federally insured limits. The Company does not believe it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

The Company has historically generated the majority of its revenue from its collaborative research and license agreements. As of September 30, 2025 and 2024, accounts receivable consisted of amounts due from the Company’s principal collaborator (see Note 7).

The Company is completely dependent on third-party manufacturers for product supply for preclinical and clinical research activities. The Company relies and expects to continue to rely exclusively on several manufacturers to supply the Company with its drug supply requirements related to these activities. These research programs would be adversely affected by a significant interruption in the supply from these third-party manufacturers.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. A fair value hierarchy is based on three levels of inputs that are used to measure fair value, of which the first two levels are considered observable and the last is considered unobservable:

•

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

•

Level 2—Observable inputs (other than Level 1 quoted prices) such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

•

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

The Company’s instruments that are carried at fair value are cash equivalents, short-term marketable securities and the Series 1 nonconvertible preferred stock. The carrying values of accounts receivable, prepaid expenses and other current assets, accounts payable, and accrued expenses and other current liabilities approximate their fair value due to the short-term nature of these assets and liabilities.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the following estimated useful lives:

Laboratory and office equipment 5 years

Leasehold improvements Shorter of life of lease or estimated useful life

Purchased software 3 years

Computer equipment 3 years

Furniture 7 years

Expenditures for repairs and maintenance of assets are charged to expense as incurred. Costs of major additions and betterments are capitalized and depreciated on a straight-line basis over their useful lives. Upon retirement or sale, the cost and related accumulated depreciation of assets disposed are removed from the accounts and any resulting gain or loss is included in other income (expense) in the consolidated statements of operations.

Leases

The Company accounts for a contract as a lease when it has the right to control the asset for a period of time while obtaining substantially all of the asset’s economic benefits. The Company determines if an arrangement is a lease or contains an embedded lease

F-10

at inception. For arrangements that meet the definition of a lease, the Company determines the initial classification and measurement of its right-of-use asset and lease liability at the lease commencement date and thereafter if modified. The lease term includes any renewal options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its estimated secured incremental borrowing rate for that lease term. The Company’s policy is to not record leases with an original term of 12 months or less on its consolidated balance sheets and recognizes those lease payments in the consolidated statements of operations on a straight-line basis over the lease term.

In addition to rent, the leases may require the Company to pay additional costs, such as utilities, maintenance and other operating costs, which are generally referred to as non-lease components. The Company has elected to not separate lease and non-lease components. Only the fixed costs for lease components and their associated non-lease components are accounted for as a single lease component and recognized as part of a right-of-use asset and lease liability. Rent expense for operating leases is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments and is included in operating expense in the consolidated statements of operations.

Impairment of Long-Lived Assets

The Company reviews long-lived assets, primarily property and equipment and right-of-use assets, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets.

Liability Related to the Sale of Future Royalties

In April 2023, the Company entered into a royalty sale agreement with an affiliate of OMERS, pursuant to which the Company was paid a $200,000 cash purchase price in exchange for 54.5% of the Company’s future quarterly royalty payments on net sales of MAVYRET/MAVIRET. The Company recognized the $200,000 received from OMERS as a liability on its consolidated balance sheets because the $200,000 will be paid back to OMERS up to a 1.42 capped amount and the Company has significant continuing involvement under the AbbVie Agreement. Interest expense for the liability related to the sale of future royalties is recognized using the effective interest rate method over the term of the royalty sale agreement.

The liability related to the sale of future royalties and related interest expense are based on current estimates of future royalties, which the Company determines by using third-party forecasts of MAVYRET/MAVIRET sales. The Company periodically assesses the forecasted sales and to the extent the amount or timing of future estimated royalty payments is materially different than previous estimates, the Company will account for any such change by adjusting the liability related to the sale of future royalties and prospectively recognizing the related non-cash interest expense.

Revenue Recognition

The Company’s revenue has been generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables, which may include (i) licenses, (ii) research and development activities, and (iii) participation in joint research and development steering committees. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, and royalty payments based on product sales derived from the collaboration.

The Company recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. The Company receives sales-based royalties for which the license is deemed to be the predominant item to which the royalties relate and thus the Company recognizes sales-based royalties as the underlying sales are earned.

Research and Development Costs

Included in research and development costs are wages, stock-based compensation and benefits of employees performing research and development, third-party license fees and other operational costs related to the Company’s research and development activities, including facility-related expenses and external costs of outside contractors engaged to conduct both preclinical and clinical studies

F-11

and manufacture quantities of product for preclinical and clinical studies. The Company expenses the cost of each contract as the work is performed.

Upfront payments and milestone payments made for the licensing of technology are expensed as research and development in the period in which they are incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed.

Research and Development and Pharmaceutical Drug Manufacturing Accruals

The Company has entered into various contracts with third parties to perform research and development and pharmaceutical drug manufacturing. This includes contracts with contract research organizations (“CROs”), clinical manufacturing organizations (“CMOs”), testing laboratories, research hospitals and not for profit organizations and other entities to support our research and development activities. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of period end. The accrual estimates are based on a number of factors, including the Company’s knowledge of the research and development programs and pharmaceutical drug manufacturing activities and associated timelines, invoicing to date, and the provisions in the contract. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from our estimates.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are recorded as general and administrative expenses as incurred.

Stock-Based Compensation

The Company measures all stock options and other stock-based awards granted to employees at fair value on the date of grant. The Company uses the Black-Scholes option-pricing model in the valuation of its stock options. The fair value of restricted stock units with service-based and performance-based vesting is based on the fair value of the stock on the date of grant. The Company uses the Monte-Carlo model to calculate the fair value on the date of grant of market-based awards. The fair value of service-based awards is recognized as stock-based compensation expense over the requisite service period, which is generally the vesting period of the respective award. For awards with graded vesting, the straight-line method of expense recognition is applied to all awards with service-only based conditions. The Company uses the graded-vesting method to record the expense of awards with both service-based and performance-based vesting conditions, commencing once achievement of the performance condition becomes probable. The Company classifies stock-based compensation expense in the consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified. The Company accounts for stock-based compensation expense related to forfeitures as the forfeitures occur.

Income Taxes

The Company accounts for income taxes using 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 recognized in the financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in income tax expense.

The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. The realization of deferred tax assets is dependent upon the Company’s ability to generate future taxable income during the periods in which those temporary differences become deductible. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

Uncertain tax positions represent tax positions for which reserves have been established. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more likely than not to be sustained, the tax position is then assessed to determine the amount of benefit to be recognized in the financial statements. The amount that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. Income tax expense includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

F-12

Net Income (Loss) per Share

Basic net income (loss) per common share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock options and unvested restricted stock units. For periods in which the Company reported a net loss, diluted net loss per common share is the same as basic net loss per common share, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

The Company reported net losses for each of the years ended September 30, 2025, 2024, and 2023. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:

Years Ended September 30,

(in thousands)

Segment Data

The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is a biotechnology company focused on discovering and developing small molecule drugs, with an emphasis on treatments for viral infections. Revenue is generated exclusively from transactions occurring with partners located in the United States, and all assets are held in the United States.

Comprehensive Income (Loss)

Comprehensive income (loss) includes net income (loss) as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income (loss) is unrealized gains and losses on available-for-sale marketable securities.

Going Concern

In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) (“ASU 2014-15”). The Company adopted this standard as of September 30, 2017. The standard requires the Company to assess its ability to continue as a going concern one year beyond the date of filing and, in certain circumstances, provide additional footnote disclosures. Based on a detailed cash forecast incorporating current research and development activities and related spending plans, the Company believes that its current cash, cash equivalents and short-term marketable securities on hand at September 30, 2025 will enable us to fund our operating expenses and capital expenditure requirements for at least the next twelve months beyond the date of issuance of these consolidated financial statements. The amount of capital available will depend on the Company’s management of its existing cash, cash equivalents and short-term marketable securities, as well as the cash flows from our retained portion of future HCV royalties. If the Company should require financing beyond these resources to fund its research and development efforts, it may not be able to obtain financing on acceptable terms, or at all.

Recently Adopted Accounting Pronouncements

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280) ("ASU 2023-07"), which requires public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. This amendment is effective for the Company in the fiscal year beginning October 1, 2024, and interim periods within the fiscal year beginning October 1, 2025, on a retrospective basis with early adoption permitted. The Company adopted ASU 2023-07 during the year ended September 30, 2025. See Note 16, Segment Information, for further information and disclosures.

Recently Issued Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740) ("ASU 2023-09"), which requires public entities, on an annual basis, to provide disclosure of specific categories in the rate reconciliation, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for the Company in the fiscal year beginning October 1, 2025, with early

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adoption permitted. The Company is currently evaluating the potential impact that ASU 2023-09 may have on its financial statement disclosures.

In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40) ("ASU 2024-03"), which requires public entities to provide disaggregated disclosure of income statement expenses. Public entities are required to disaggregate, in a tabular presentation, each relevant expense caption on the face of the consolidated statements of operations such as the following expenses: purchases of inventory, employee compensation, intangible asset amortization, and depreciation. ASU 2024-03 is effective for the Company in the fiscal year beginning October 1, 2027, with early adoption permitted. The Company is currently evaluating the potential impact that ASU 2024-03 may have on its financial statement disclosures.

3. Fair Value of Financial Assets and Liabilities

The following tables present information about the Company’s financial assets and liabilities that were subject to fair value measurement on a recurring basis as of September 30, 2025 and 2024 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value:

Fair Value Measurements at September 30, 2025 Using:

Level 1 Level 2 Level 3 Total

(in thousands)

Assets:

Cash equivalents:

Marketable securities:

Liabilities:

Series 1 nonconvertible preferred stock — — 1,311 1,311

Fair Value Measurements at September 30, 2024 Using:

Level 1 Level 2 Level 3 Total

(in thousands)

Assets:

Cash equivalents:

Marketable securities:

Liabilities:

Series 1 nonconvertible preferred stock — — 1,350 1,350

Cash equivalents as of September 30, 2025 and 2024 consist of money market funds that are readily convertible to cash and with less than 90 days until maturity.

During the years ended September 30, 2025, 2024, and 2023, there were no transfers between Level 1, Level 2 and Level 3.

The fair value of Level 1 instruments are valued using quoted prices in active markets. The fair value of Level 2 instruments classified as marketable securities were determined through third-party pricing services. The pricing services use many observable market inputs to determine value, including reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, and current spot rates.

The outstanding shares of Series 1 nonconvertible preferred stock as of September 30, 2025 and 2024 are measured at fair value. These outstanding shares are financial instruments that might require a transfer of assets because of the liquidation features in the contract and are therefore recorded as liabilities and measured at fair value. The fair value of the outstanding shares is based on significant inputs not observable in the market, which represent a Level 3 measurement within the fair value hierarchy. The Company utilizes a probability-weighted valuation model, which takes into consideration various outcomes that may require the Company to transfer assets upon liquidation. Changes in the fair values of the Series 1 nonconvertible preferred stock are recognized in other income (expense) in the consolidated statements of operations.

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The recurring Level 3 fair value measurements of the Company’s outstanding Series 1 nonconvertible preferred stock using probability-weighted discounted cash flow include the following significant unobservable inputs:

Series 1 nonconvertible preferred stock Range

September 30,

Probabilities of payout 0%-65% 0%-65%

The following table provides a rollforward of the aggregate fair value of the Company’s outstanding Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs:

Series 1 Nonconvertible Preferred Stock

(in thousands)

Change in fair value —

Change in fair value (73 )

Change in fair value (39 )

In April 2023, the Company entered into a royalty sale agreement with an affiliate of OMERS, pursuant to which the Company was paid a $200,000 cash purchase price in exchange for 54.5% of future quarterly royalty payments on net sales of MAVYRET/MAVIRET, after June 30, 2023, through June 30, 2032, subject to a cap on aggregate payments equal to 1.42 times the purchase price. The Company accounted for the upfront payment as a liability related to the sale of future royalties. The carrying value of the liability related to the sale of future royalties approximates fair value as of September 30, 2025 and 2024 and is based on current estimates of future royalties expected to be paid to OMERS over the next 10 years, which are considered Level 3 inputs. See Note 8 for a rollforward of the liability.

4. Marketable Securities

As of September 30, 2025 and 2024, the fair value of available-for-sale marketable securities, by type of security, was as follows:

(in thousands)

(in thousands)

As of September 30, 2025 and 2024 marketable securities consisted of investments that mature within one year.

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5. Property and Equipment, Net

Property and equipment, net consisted of the following as of September 30, 2025 and 2024:

September 30,

(in thousands)

Construction in progress — 22,748

Less: Accumulated depreciation and amortization (23,805 ) (25,047 )

As of September 30, 2024, construction in progress related primarily to leasehold improvements for the new laboratory and office space located at 4 Kingsbury Avenue in Watertown, Massachusetts which was completed during the year ended September 30, 2025. Depreciation and amortization expense for property and equipment, was $4,586, $2,336 and $2,371 for the years ended September 30, 2025, 2024, and 2023, respectively.

6. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following as of September 30, 2025 and 2024:

September 30,

(in thousands)

Accrued payroll and related expenses $ 6,469 $ 6,570

Accrued research and development expenses 1,800 3,087

Accrued pharmaceutical drug manufacturing 2,691 930

7. Collaboration Agreements

AbbVie Collaboration

The Company has a Collaborative Development and License Agreement (as amended, the “AbbVie Agreement”), with AbbVie to identify, develop and commercialize HCV NS3 and NS3/4A protease inhibitor compounds, including paritaprevir and glecaprevir, under which the Company has received license payments, proceeds from a sale of preferred stock, research funding payments, milestone payments and royalties totaling approximately $1,349,000 through September 30, 2025. Since the Company satisfied all of its performance obligations under the AbbVie Agreement by the end of fiscal 2011, all milestone payments received since then have been recognized as revenue when the milestones were achieved by AbbVie.

The Company is receiving annually tiered royalties per Company protease product ranging from ten percent up to twenty percent, or on a blended basis from ten percent up to the high teens, on the portion of AbbVie’s calendar year net sales of each HCV regimen that is allocated to the protease inhibitor in the regimen. Beginning with each January 1, the cumulative net sales of a given royalty-bearing protease inhibitor product start at zero for purposes of calculating the tiered royalties on a product-by-product basis. The following table details the royalty tiers associated with cumulative calendar year net sales allocated to each royalty-bearing product as provided in the AbbVie Agreement:

Calendar Year Net Sales Royalty Tier

(in thousands) (%)

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Royalties owed to the Company under the agreement can be reduced by AbbVie in certain circumstances, including (i) if AbbVie exercises its right to license or otherwise acquire rights to intellectual property controlled by a third party where a product could not be legally developed or commercialized in a country without the third-party intellectual property right, (ii) where a product developed under the collaboration agreement is sold in a country and not covered by a valid patent claim in such country, and (iii) where sales of a generic product are equal to at least a specified percentage of AbbVie’s market share of its product in a country.

AbbVie’s obligation to pay royalties on a product developed under the agreement expires on a country-by-country basis upon the later of (i) the date of expiration of the last of the licensed patents with a valid claim covering the product in the applicable country, or (ii) ten years after the first commercial sale of the product in the applicable country.

Subject to certain exceptions, a party’s rights and obligations under the agreement continue until (i) such time as AbbVie is no longer developing a product candidate or (ii) if, as of the time AbbVie is no longer developing any product candidates, AbbVie is commercializing any other protease inhibitor product, such time as all royalty terms for all covered products have ended. Accordingly, the final expiration date of the agreement is currently indeterminable.

Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice.

If the Company terminates the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted the Company (i) a non-exclusive, perpetual, fully-paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate, and (ii) an exclusive (even as to AbbVie), perpetual, fully-paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in any joint intellectual property rights to develop product candidates resulting from covered compounds and to commercialize any products derived from such compounds. Upon the Company’s request, AbbVie will also transfer to the Company all right, title and interest in any related product trademarks, regulatory filings and clinical trials.

If AbbVie terminates the agreement for the Company’s uncured breach, the milestone and royalty payments payable by AbbVie may be reduced, the licenses granted to AbbVie will remain in place, the Company will be deemed to have granted AbbVie an exclusive license under the Company’s interest in joint intellectual property, AbbVie will continue to have the right to commercialize any covered products, and all rights and licenses granted to the Company by AbbVie will terminate.

8. Liability Related to the Sale of Future Royalties

In April 2023, the Company entered into a royalty sale agreement with an affiliate of OMERS, pursuant to which the Company was paid a $200,000 cash purchase price in exchange for 54.5% of future quarterly royalty payments on net sales of MAVYRET/MAVIRET, after June 30, 2023, through June 30, 2032, subject to a cap on aggregate payments equal to 1.42 times the purchase price.

Because the royalty sale agreement will be paid back to OMERS up to a capped amount as well as the Company’s significant continuing involvement in the generation of future cash flows under its AbbVie Agreement, the Company recorded the proceeds from the transaction as a liability on its consolidated balance sheets which will be amortized as interest expense in the consolidated statements of operations under the effective interest rate method over the life of the royalty sale agreement. The Company will continue to record the full amount of royalties earned on MAVYRET/MAVIRET sales as royalty revenue in the consolidated statements of operations.

The Company’s liability related to the sale of future royalties is estimated based on forecasted worldwide MAVYRET/MAVYRET royalties to be paid to OMERS over the course of the royalty sale agreement. This estimate requires significant judgment, including the amount and timing of royalty payments up until the end of the royalty sale agreement, which is estimated to be the stated term of June 30, 2032. As royalties are earned by OMERS, the liability is reduced on the Company’s consolidated balance sheets.

At September 30, 2025, the estimated future cash flows resulted in an effective annual imputed interest rate of approximately 6.39%.

The following table summarizes the activity of the liability related to the sale of future royalties:

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Liability related to the sale of future royalties

(in thousands)

Balance - September 30, 2022 $ —

Proceeds from sale of future royalties 200,000

Debt issuance cost (325 )

Royalty payable to royalty purchaser (10,318 )

Interest expense, net of capitalized interest of $0 5,148

Royalty payable to purchaser (7,960 )

Payments on royalty sale liability (28,916 )

Interest expense, net of capitalized interest of $672 11,612

Royalty payable to purchaser (8,243 )

Payments on royalty sale liability (27,356 )

Interest expense, net of capitalized interest of $520 8,200

9. Stockholders’ Equity

The Company is authorized to issue 100,000 shares of common stock at a par value of $0.01 per share.Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive such dividends as may be declared by the board of directors, if any.

The Company also is authorized to issue 5,000 shares of preferred stock at a par value of $0.01 per share, of which 2,000 shares are designated as Series 1 Nonconvertible preferred stock and 3,000 shares are undesignated and unissued.

10. Series 1 Nonconvertible Preferred Stock

The Company’s Certificate of Incorporation authorizes the issuance of up to 2,000 shares of Series 1 nonconvertible preferred stock at a par value of $0.01 per share. Holders of Series 1 nonconvertible preferred stock are not entitled to receive dividends. In the event of any liquidation, deemed liquidation, dissolution or winding up of the Company, the Series 1 nonconvertible preferred stockholders are entitled to receive in preference to all other stockholders, an amount equal to $1.00 per share, adjusted for any stock dividends, stock splits or reclassifications. Series 1 nonconvertible preferred stockholders will not be entitled to vote unless required by the Company pursuant to the laws of the State of Delaware. The Company may redeem the Series 1 nonconvertible preferred stock with the approval of the holders of a majority of the outstanding shares of Series 1 nonconvertible preferred stock at a redemption price of $1.00 per share. The Company must redeem the stock within 60 days of such election. Shares that are redeemed will be retired or canceled and not reissued by the Company. As these shares qualify as a derivative, they are classified as a liability on the Company’s consolidated balance sheet.

As of September 30, 2025 and 2024, 1,930 shares of Series 1 nonconvertible preferred stock were issued and outstanding. For the years ended September 30, 2025, 2024, and 2023, the remeasurement of the Series 1 nonconvertible preferred stock resulted in non-cash gain of $39, $73 and $0, respectively, which was recorded in other income (expense) in the consolidated statements of operations. The total fair value of the Series 1 nonconvertible preferred stock was $1,311 and $1,350 as of September 30, 2025 and 2024, respectively.

11. Stock-Based Awards

The Company grants stock-based awards, including stock options, restricted stock units and other unit awards under its 2019 Equity Incentive Plan (the “2019 Plan”), which was approved by its stockholders on February 28, 2019 and amended in March 2021, March 2022, March 2023, March 2024 and March 2025 and its 2024 Inducement Stock Incentive Plan (“2024 Inducement Plan”). The Company also has outstanding stock option awards under its 2012 Equity Incentive Plan (the “2012 Plan”), but is no longer granting awards under this plan. The Company’s 2019 Plan permits the Company to sell or issue awards of common stock or restricted common stock or to grant awards of incentive stock options or nonqualified stock options for the purchase of common stock, restricted stock units, performance units, stock appreciation rights or other cash incentive awards, to employees, members of the board of directors and consultants of the Company. The number of shares of common stock that may be issued under the 2019 Plan is subject to increase by the number of shares forfeited under any options forfeited and not exercised under the 2019 Plan or any predecessor plans such as the 2012 Plan. Pursuant to the Company's 2024 Inducement Plan, the Company may grant non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards to persons who (i) were not previously an employee or director of the Company or (ii) are commencing employment with the Company following a bona fide period of

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non-employment, in either case as an inducement material to the individual’s entering into employment with the Company and in accordance with the requirements of Nasdaq Stock Market Rule 5635(c)(4). As of September 30, 2025, 1,985 shares remained available for future awards under the 2019 Plan and 2024 Inducement Plan.

Options granted to employees under the 2019 Plan and the 2024 Inducement Plan generally vest over four years and to non-employee directors over one year, and expire after ten years. As required under the equity plans, the exercise price for awards granted is not to be less than the fair value of common shares on the date of grant. Restricted stock units with service-based vesting conditions generally vest over four years.

Stock Option Valuation

The fair value of each stock option award is determined on the date of grant using the Black-Scholes option-pricing model. The volatility has been determined using the Company’s traded stock price to estimate expected volatility. The Company utilized historical data to determine the expected term of stock options granted. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is zero due to the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The relevant data used to determine the value of the stock option awards are as follows, presented on a weighted average basis:

Years Ended September 30,

Expected volatility 53 % 52 % 48 %

Expected dividends 0 % 0 % 0 %

Weighted average grant date fair value $ 4.80 $ 5.43 $ 22.71

The following table summarizes stock option activity, including aggregate intrinsic value for the year ended September 30, 2025:

(in thousands) (in thousands)

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock. The following tables summarize additional exercise and grant date information:

Years Ended September 30,

(in thousands)

Aggregate intrinsic value of stock options exercised $ 17 $ 93 $ 3,295

Proceeds to Company from stock options exercised $ 145 $ 147 $ 2,208

Market and Performance-Based Stock Unit Awards

The Company awards both performance share units (“PSUs”) and relative total stockholder return units (“rTSRUs”) to its executive officers.

The PSUs vest and result in issuance, or settlement, of common shares for each recipient, based upon the recipient’s continued employment with the Company through the settlement date of the award and the Company’s achievement of specified research and development milestones. The requisite service period of the PSUs is generally two years. The fair value of PSUs is based on the fair

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value of the stock on the date of grant, which is determined to be the closing price of the Company's common stock. Stock-based compensation expense for PSUs is recorded in the statements of operations over the service period, commencing when it is probable that the specified research and development milestone is achieved.

The rTSRUs vest and result in the issuance of common stock based upon the recipient’s continuing employment with the Company through the settlement date of the award and the relative ranking of the total stockholder return, or TSR, of the Company’s common stock in relation to the TSR of the component companies in the Nasdaq Biotech Index over two specified periods that are two years apart, based on a comparison of average closing stock prices in specified periods noted in the award agreement. The number of market-based rTSRUs awarded represents the target number of shares of common stock that may be earned; however, the actual number of shares that may be earned ranges from 0% to 150% of the target number, depending on the award agreement and the year of the award. The Company used a Monte Carlo model to estimate the grant-date fair value of the rTSRUs. Stock-based compensation expense for rTSRUs is recorded in the statements of operations over the service period regardless of whether the market condition is achieved.

Assumptions and estimates utilized in the calculation of the fair value of the rTSRUs include the risk-free interest rate, dividend yield, expected volatility based on the historical volatility of publicly traded peer companies and the remaining performance period of the award. The table below sets forth the weighted average grant date fair value assumptions used to value the rTSRUs:

Years Ended September 30,

Dividend yield 0 % 0 % 0 %

Expected volatility 70 % 74 % 77 %

The following table summarizes PSU and rTSRU activity (at target) for the year ended September 30, 2025:

PSUs rTSRUs

(in thousands, except per share data)

The total fair value of PSUs and rTSRUs vested during the years ended September 30, 2025, 2024, and 2023 were $396, $307, and $8,103, respectively.

Restricted Stock Units

The following table summarizes the restricted stock unit activity for the year ending September 30, 2025:

RestrictedStock Units Weighted Average Grant Date Fair Value perShare

(in thousands, except per share data)

The total fair value of restricted stock units vested during the years ended September 30, 2025, 2024, and 2023 were $1,290, $1,228, and $2,590, respectively.

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Stock-Based Compensation Expense

The Company recorded the following stock-based compensation expense for the years ended September 30, 2025, 2024, and 2023:

Years Ended September 30,

(in thousands)