ENANTA PHARMACEUTICALS INC

Previous wording

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

Current wording

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.

Previous wording

We discovered glecaprevir, the second of two antiviral protease inhibitors discovered and developed through our 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.

Current wording

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.

Previous wording

Our active development programs in virology are focused on respiratory syncytial virus, or RSV, the most common cause of bronchiolitis and pneumonia and leading cause of U.S. hospitalization in young children and a significant cause of respiratory illness in older adults, with estimates suggesting that on average each year RSV leads to three million hospitalizations globally in children under 5 years old and 177,000 hospitalizations in the U.S. in adults over the age of 65.

Current wording

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.

Previous wording

In immunology, we are designing and developing highly potent and selective, oral small molecule inhibitors for the treatment of inflammatory disease by targeting key mechanisms of immune response. Our initial focus has been on mechanisms involved in an overactive type 2 immune response, which is the reaction of the body's immune system when the body detects infections or allergens and sends out immune cells to fight them. An overactive response is a primary driver of a number of inflammatory diseases.

Current wording

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.

Previous wording

The receptor tyrosine kinase, known as KIT, which is critical for regulating mast cell activity; and

Current wording

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

Previous wording

STAT6, a transcription factor uniquely responsible for interleukin-4 (IL-4)/interleukin-13 (IL-13) cell signaling, the factors that play important roles in regulating the responses of lymphocytes, myeloid cells, and non-hematopoietic cells within the immune system.

Current wording

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.

Previous wording

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 immunology drug development efforts on the following disease indications:

Current wording

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:

Previous wording

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; and

Current wording

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

Previous wording

As of September 30, 2024, we had $248.2 million in cash, cash equivalents and short-term marketable securities. We believe that our existing cash, cash equivalents and short-term marketable securities as of September 30, 2024, as well as the cash flows from our retained portion of future HCV royalties will enable us to fund our operating expenses and capital expenditure requirements into fiscal 2027.

Current wording

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

Previous wording

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. 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 2-DAA glecaprevir/pibrentasvir combination in MAVYRET/MAVIRET. The annual royalty tiers return to the lowest tier for sales on and after each January 1.

Current wording

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.

Previous wording

We are currently funding all research and development for our wholly-owned programs, which are targeted toward the discovery and development of novel compounds. As of the date of this report, we are conducting two Phase 2b studies of zelicapavir and have recently completed 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 .

Current wording

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.

Previous wording

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 will not conduct any further development of EDP-235 into Phase 3 studies and we made important adjustments to reduce our spending significantly in 2024.

Current wording

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.

Previous wording

To date, 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. We believe that our existing cash, cash equivalents and short-term marketable securities as of September 30, 2024, as well as the cash flows from our retained portion of future HCV royalties, will enable us to fund our operating expenses and capital expenditure requirements into fiscal 2027.

Current wording

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.

Previous wording

Our revenue is primarily derived from our collaboration agreement with AbbVie and AbbVie’s sales of MAVYRET/MAVIRET, an 8-week treatment regimen for 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.

Current wording

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.

Previous wording

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 will not conduct any further development of EDP-235 into Phase 3 studies and we made important adjustments to reduce our spending significantly in 2024. 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.

Current wording

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.

Previous wording

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 suit.

Current wording

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.

Previous wording

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, but we anticipate inflation may impact future periods.

Current wording

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.

Previous wording

We recognized revenue of $67.6 million and $79.2 million during the years ended September 30, 2024 and 2023, 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 2023.

Current wording

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.

Previous wording

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 and the number of patients treated. 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.

Current wording

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.

Previous wording

Research and development expenses for the year ended September 30, 2024 decreased by $32.0 million compared to the same period in 2023.

Current wording

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

Previous wording

The costs in our immunology programs increased by $24.5 million as this is a new therapeutic area of focus for the company.

Current wording

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

Previous wording

General and administrative expenses increased by $5.0 million for the year ended September 30, 2024, compared to the same period in 2023, due to an increase in legal expenses related to our patent infringement suit against Pfizer.

Current wording

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.

Previous wording

Interest expense increased by $5.8 million for the year ended September 30, 2024, as compared to the same period in 2023, due to the timing of the royalty sale agreement entered into during April 2023 with an affiliate of OMERS.

Current wording

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.

Previous wording

Interest and investment income, net, increased by $3.4 million for the year ended September 30, 2024, as compared to the same period in 2023. The increase was due to an increase in average invested cash due to receipt of $200.0 million from OMERS in April 2023 as well as changes in interest rates year over year.

Current wording

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.

Previous wording

During the year ended September 30, 2024 we recorded an income tax benefit of $1.7 million representing interest recorded on a pending federal tax refund. The income tax expense during the year ended September 30, 2023 was driven by the receipt of $200.0 million from the royalty sale agreement, which was taxable for federal and state purposes and partially offset by utilization of federal net operating losses and research and development tax credit carryforwards as well as a deduction for foreign derived intangible income.

Current wording

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.

Previous wording

We fund our operations with cash flows from our retained portion of our royalty revenue and our existing financial resources. At September 30, 2024, our principal sources of liquidity were cash and cash equivalents and short-term marketable securities of $248.2 million.

Current wording

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.

Previous wording

Cash used in operating activities was $78.8 million for the year ended September 30, 2024 as compared to cash used in operating activities of $103.2 million for the same period in 2023. The decrease in cash used in operating activities was primarily driven by lower research and development payments, offset by lower cash receipts associated with our AbbVie agreement as we now only retain 45.5% of cash royalties following the royalty sale agreement with OMERS.

Current wording

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.

Previous wording

Cash provided by investing activities was $58.2 million for the year ended September 30, 2024 as compared to cash used in investing activities of $53.6 million for the same period in 2023. Our cash provided by investing activities increased $111.8 million, driven by timing of purchases, sales and maturities of marketable securities in 2024 compared to 2023. This increase was partially offset by increased capital expenditures in fiscal 2024 for the buildout of our new office and laboratory space at 4 Kingsbury Avenue.

Current wording

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.

Previous wording

Cash used in financing activities was $27.6 million for the year ended September 30, 2024 as compared to cash provided by financing activities of $198.1 million for the same period in 2023. Our cash used in financing activities decreased $225.8 million, driven primarily by the timing of receipt of $200.0 million from OMERS for our royalty sale agreement executed in April 2023.

Current wording

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.

Previous wording

As of September 30, 2024, we had $248.2 million in cash, cash equivalents and short-term marketable securities. We believe that our existing cash, cash equivalents and short-term marketable securities as of September 30, 2024, as well as the cash flows from our retained portion of future HCV royalties will enable us to fund our operating expenses and capital expenditure requirements into fiscal 2027. 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.

Current wording

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.

Previous wording

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

Current wording

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;

Previous wording

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

Current wording

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

Previous wording

Total estimated minimum lease payments for the next 5 years and thereafter under our existing facility and leased equipment agreements are $8.7 million in 2025, $8.5 million in 2026, $8.7 million in 2027, $9.0 million in 2028, $9.3 million in 2029, and $50.6 million thereafter.

Current wording

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.

Previous wording

As of September 30, 2024, 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 $1.4 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, 2024. 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.

Current wording

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.