ENTA

Dosing Initiated in LOTUS, a Phase 2b Pediatric Trial of Zelicapavir; Topline Data Expected in 2027 On Track to Initiate RESOLVE, a Registrational Phase 2b/3 High-Risk Adult Trial of Zelicapavir in 4Q 2026; Topline Phase 2b Data Expected in 2027 On Track to Report Topline Data from a Phase 1 Trial of EDP-978, an Oral, Once-Daily KIT Inhibitor in Development for the Treatment of Urticaria, in 4Q 2026 On Track to File an IND for EPS-3903, an Oral, Once-Daily STAT6 Inhibitor and to Select an MRGPRX2 Development Candidate, in 2H 2026 Cash and Marketable Securities Totaling $211.5 Million at June 30, 2026, as well as Continuing Retained Royalties, with Cash Runway Expected to Fund Operations into Fiscal 2029 WATERTOWN, Mass., August 10, 2026--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today reported financial results for its fiscal third quarter ended June 30, 2026. "During the quarter, we continued to build momentum across both our RSV and immunology programs," said Jay R. Luly, Ph.D., President and Chief Executive Officer of Enanta. "Dosing began in LOTUS, our Phase 2b trial of zelicapavir in pediatric patients with RSV in Thailand, with topline data anticipated in 2027. We also announced plans to advance zelicapavir into a registrational Phase 2b/3 trial in high-risk adults with RSV and remain on track to initiate this study, RESOLVE, in the fourth quarter, with initial Phase 2b data expected next year. With no approved antiviral therapies currently available for RSV, we believe zelicapavir is uniquely positioned to address a substantial unmet need across both high-risk adult and pediatric populations. We continue to execute our clinical development plan and aim to deliver what could become the first approved antiviral treatment for RSV. Additionally, in immunology, we are focused on reporting topline data from our Phase 1 study of EDP-978 in the fourth quarter of 2026, while also advancing EPS-3903, our oral, once-daily STAT6 inhibitor, toward an IND filing this year. Further, we are on track to select an MRGPRX2 development candidate in the second half of 2026. With a catalyst rich year ahead, we have multiple opportunities to drive shareholder value and bring important treatments to patients in need." Fiscal Third Quarter Ended June 30, 2026 Financial Results Total revenue for the three months ended June 30, 2026 was $14.4 million and consisted of royalty revenue from worldwide net sales of AbbVie’s hepatitis C virus (HCV) regimen MAVYRET®/MAVIRET® (glecaprevir/pibrentasvir), compared to $18.3 million for the three months ended June 30, 2025. The decrease in revenue is primarily due to AbbVie’s lower reported HCV sales as compared to the same period in 2025. A portion (54.5%) of Enanta’s ongoing royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET® is paid to OMERS, one of Canada’s largest defined benefit pension plans, pursuant to a royalty sale transaction affecting royalties earned after June 2023. For financial reporting purposes, the transaction was treated as debt, with the upfront purchase payment of $200.0 million recorded as a liability. Each quarter, Enanta records 100% of the royalty earned as revenue and then amortizes the debt liability proportionally as 54.5% of the cash royalty payments are paid to OMERS through June 30, 2032, subject to a cap of 1.42 times the purchase price, after which point 100% of the cash royalty payments will be retained by Enanta. Interest expense was $4.1 million for the three months ended June 30, 2026, as compared to $1.6 million for the period ended June 30, 2025. The increase was due to the increase in forecasted royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET®. Research and development expenses totaled $22.1 million for the three months ended June 30, 2026, compared to $27.2 million for the three months ended June 30, 2025. The decrease was due to a decrease in clinical trial expenses for Enanta’s RSV programs, partially offset by increased costs associated with the Company’s immunology programs. General and administrative expenses totaled $9.5 million for the three months ended June 30, 2026, compared to $10.0 million for the three months ended June 30, 2025. The decrease was primarily due to a decrease in stock-based compensation expenses. Interest and investment income, net, totaled $1.9 million for the three months ended June 30, 2026, compared to $2.3 million for the three months ended June 30, 2025. The decrease in interest and investment income was due to lower interest rates year over year. Enanta recorded an income tax expense of less than $0.1 million for the three months ended June 30, 2026 compared to an income tax expense of less than $0.1 million for the three months ended June 30, 2025. Net loss for the three months ended June 30, 2026 was $19.5 million, or a loss of $0.67 per diluted common share, compared to a net loss of $18.3 million, or a loss of $0.85 per diluted common share, for the corresponding period in 2025. Enanta’s cash, cash equivalents and short-term and long-term marketable securities totaled $211.5 million at June 30, 2026. Enanta expects that its current cash, cash equivalents and marketable securities, as well as its retained portion of future royalty revenue, will be sufficient to meet the anticipated cash requirements of its existing business and development programs into fiscal 2029. Virology Enanta’s virology pipeline includes the leading portfolio of RSV treatments in clinical development, consisting of zelicapavir, a once-daily N-protein inhibitor, and EDP-323, a once-daily L-protein inhibitor, both of which received Fast Track designation from the U.S. Food and Drug Administration (FDA). Dosing began in LOTUS, a Phase 2b study of zelicapavir in pediatric patients with RSV. LOTUS will evaluate zelicapavir in approximately 150 hospitalized and non-hospitalized children aged 28 days to 36 months who test positive for RSV and have experienced symptoms for up to 72 hours. Conducted in collaboration with the Penta Foundation and the AMS-PHPT Research Unit at Chiang Mai University, LOTUS is designed to evaluate the efficacy, safety, and antiviral activity of zelicapavir, with topline data expected in 2027. In June, Enanta announced its advancement of zelicapavir into registrational development, following an End-of-Phase 2 meeting with the FDA. Advancement into registrational development through a single Phase 2b/3 trial further highlights zelicapavir’s potential to become the first approved antiviral therapy for RSV and supports Enanta's continued leadership in RSV drug development. Enanta’s second RSV candidate, EDP-323, can be used alone or in combination with other agents, such as zelicapavir, to potentially broaden the treatment window or addressable patient populations. Previously, the Company reported positive results from a Phase 2a challenge study of healthy adults infected with RSV, in which treatment with EDP-323 achieved highly statistically significant reductions in both viral load and clinical symptoms compared to placebo. Immunology Enanta’s immunology pipeline is focused on designing and developing highly potent and selective oral inhibitors for the treatment of inflammatory diseases, by targeting key drivers of the type 2 immune response. Enanta’s lead immunology program, EDP-978, is a potent and selective once-daily oral KIT inhibitor in development for the treatment of chronic urticaria and potentially other mast cell-mediated diseases. In April, the Company announced that the first participant was dosed in a randomized, double-blind, placebo-controlled, first-in-human Phase 1 clinical trial. The trial is expected to enroll approximately 98 healthy adult volunteers ranging in age from 18 to 65 years old to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics, including serum tryptase, of EDP-978. The trial includes a single ascending dose phase, with a two-part food-effect cohort, and a multiple ascending dose phase with a 14-day treatment period. The Company expects to report topline data from the trial in the fourth quarter of 2026. Enanta’s second immunology program, EPS-3903, is a novel, potent and selective oral STAT6 inhibitor, in development for the treatment of atopic dermatitis and other diseases currently treated by dupilumab. The Company is currently performing scale-up and IND-enabling activities and is targeting an IND filing in the second half of 2026. Enanta’s third immunology program targets MRGPRX2, a non-canonical G-Protein-Coupled-Receptor (GPCR) expressed predominantly on mast cells, as well as peripheral neurons. Inhibiting MRGPRX2 may have potential to address multiple mast-cell driven diseases, as well as having potential in migraine. Currently, the Company is evaluating multiple compounds in preclinical studies and expects to select a development candidate in the second half of 2026. Corporate In June, Enanta announced that its partner AbbVie received European Commission approval of MAVIRET® (glecaprevir/pibrentasvir) for the treatment of acute hepatitis C virus (HCV) infection in adults and children aged three years and older. MAVIRET is now the only treatment approved in the European Union for both acute and chronic HCV infection. Glecaprevir, one of the two direct-acting antivirals in MAVIRET, was discovered by Enanta and is a source of ongoing royalty revenue for the Company. In June, the United States Court of Appeals for the Federal Circuit affirmed the summary judgment decision of the United States District Court for the District of Massachusetts in the Company’s suit against Pfizer Inc. and ruled that the claims of U.S. Patent No. 11,358,953 were invalid. In July, the Company filed a combined petition for panel or en banc rehearing of the Federal Circuit’s decision. A hearing for the patent infringement action against Pfizer in the Unified Patent Court (UPC) of the European Union, and Pfizer’s counterclaim for revocation, has been scheduled for September 29, 2026. Enanta expects a decision from the UPC within weeks after the hearing. Enanta plans to issue its fiscal fourth quarter financial results press release on November 16, 2026. About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs for viral infections and immunological diseases. In virology, Enanta’s clinical programs are focused on the development of first-in-disease and best-in-disease treatments for respiratory syncytial virus (RSV). The Company’s immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, with KIT, STAT6 and MRGPRX2 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of the only treatment approved for curing both acute and chronic hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information. Forward-Looking Statements This press release contains forward-looking statements, including statements with respect to the timeline and prospects for advancement of Enanta’s clinical programs in RSV and KIT inhibition and its preclinical immunology programs, including its programs targeting STAT6 and MRGPRX2 inhibition. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and management’s beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors and risks that may affect actual results include: the impact of development, regulatory and marketing efforts of others with respect to vaccines and competitive treatments for RSV; the discovery and development risks of Enanta’s programs in virology and immunology; Enanta’s limited clinical development experience; Enanta’s ability to partner its RSV or other programs; Enanta’s need to attract and retain senior management and key research and development personnel; Enanta’s need to obtain and maintain patent protection for its product candidates and avoid potential infringement of the intellectual property rights of others; the outcome of the Federal Circuit rehearing petition and the Unified Patent Court proceedings related to Enanta’s patent claim against Pfizer; and other risk factors described or referred to in "Risk Factors" in Enanta’s Form 10-K for the fiscal year-ended September 30, 2025, and any other periodic reports filed more recently with the Securities and Exchange Commission. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Enanta undertakes no obligation to update or revise these statements, except as may be required by law. Tables to Follow View source version on businesswire.com: https://www.businesswire.com/news/home/20260810427925/en/ Contacts Media and Investors Contact: Jennifer [email protected]

Dosing Initiated in a Phase 1 Trial of EDP-978, an Oral, Once-Daily KIT Inhibitor in Development for the Treatment of Chronic Urticaria; On Track to Report Topline Data in 4Q 2026 Conducting Enabling Activities for a Pivotal Study of Zelicapavir in High-Risk Adults with Respiratory Syncytial Virus (RSV) On Track to File an IND for EPS-3903, an Oral, Once-Daily STAT6 Inhibitor Development Candidate and to Select an MRGPRX2 Development Candidate, in 2H 2026 Cash and Marketable Securities Totaling $227 Million at March 31, 2026, as well as Continuing Retained Royalties, with Cash Runway Expected to Fund Operations into Fiscal 2029 WATERTOWN, Mass., May 11, 2026--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today reported financial results for its fiscal second quarter ended March 31, 2026. "Since the inception of our immunology portfolio targeting type 2 diseases, our team has worked diligently to advance highly selective inhibitors of KIT, STAT6 and MRGPRX2 designed to enable convenient oral dosing and best-in-class profiles," said Jay Luly, Ph.D., President and Chief Executive Officer of Enanta. "This quarter, we achieved a key milestone with dosing initiation in our Phase 1 trial of EDP-978, an oral KIT inhibitor in development for chronic urticaria. Along with advancing EDP-978 into the clinic, we remain on track to file an IND for EPS-3903, our oral STAT6 inhibitor, and to nominate an MRGPRX2 development candidate, in the second half of 2026. In parallel, we are continuing to conduct enabling activities for a pivotal study of zelicapavir in adults at high risk of serious complications from RSV infection and look forward to providing an update on the development path later this quarter. With a strong balance sheet and ongoing royalty revenues, we are well-positioned to execute on our strategy and to deliver multiple value-driving milestones over the coming year." Fiscal Second Quarter Ended March 31, 2026 Financial Results Total revenue for the three months ended March 31, 2026 was $17.2 million and consisted of royalty revenue from worldwide net sales of MAVYRET®/MAVIRET® (glecaprevir/pibrentasvir), AbbVie’s treatment for hepatitis C virus, compared to $14.9 million for the three months ended March 31, 2025. The increase in revenue is due to an increase in AbbVie’s product sales quarter over quarter. A portion (54.5%) of Enanta’s ongoing royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET® is paid to OMERS, one of Canada’s largest defined benefit pension plans, pursuant to a royalty sale transaction affecting royalties earned after June 2023. For financial reporting purposes, the transaction was treated as debt, with the upfront purchase payment of $200.0 million recorded as a liability. Each quarter, Enanta records 100% of the royalty earned as revenue and then amortizes the debt liability proportionally as 54.5% of the cash royalty payments are paid to OMERS through June 30, 2032, subject to a cap of 1.42 times the purchase payment, after which point 100% of the cash royalty payments will be retained by Enanta. Interest expense was $3.3 million for the three months ended March 31, 2026, as compared to $1.7 million for the three months ended March 31, 2025. The increase was due to the increase in royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET®. Research and development expenses totaled $19.4 million for the three months ended March 31, 2026, compared to $28.1 million for the three months ended March 31, 2025. The decrease was due to a decrease in clinical trial expenses for Enanta’s RSV programs, partially offset by increased costs associated with the Company’s immunology programs. General and administrative expenses totaled $9.6 million for the three months ended March 31, 2026, compared to $11.4 million for the three months ended March 31, 2025. The decrease was primarily due to a decrease in stock-based compensation expenses. Interest and investment income, net, totaled $2.1 million for the three months ended March 31, 2026, compared to $2.3 million for the three months ended March 31, 2025. The decrease in interest and investment income was due to lower interest rates year over year. Enanta recorded an income tax expense of less than $0.1 million for the three months ended March 31, 2026 compared to an income tax benefit of $1.3 million for the three months ended March 31, 2025. Enanta recorded an additional federal income tax refund of $0.9 million during the three months ended March 31, 2025. The federal income tax refund of $33.8 million, including interest, was received in April 2025. Net loss for the three months ended March 31, 2026 was $13.1 million, or a loss of $0.45 per diluted common share, compared to a net loss of $22.6 million, or a loss of $1.06 per diluted common share, for the corresponding period in 2025. Enanta’s cash, cash equivalents and short-term and long-term marketable securities totaled $227.0 million at March 31, 2026. Enanta expects that its current cash, cash equivalents and marketable securities, as well as its retained portion of future royalty revenue will be sufficient to meet the anticipated cash requirements of its existing business and development programs into fiscal 2029. Virology Enanta’s virology pipeline includes the leading portfolio of RSV treatments in clinical development, consisting of zelicapavir, a once-daily N-protein inhibitor, and EDP-323, a once-daily L-protein inhibitor, both of which received Fast Track designation from the U.S. Food and Drug Administration (FDA). Zelicapavir was most recently evaluated in a high-risk adult outpatient population, including the elderly and those with asthma, chronic obstructive pulmonary disease, or congestive heart failure. In RSVHR, a Phase 2b study, zelicapavir demonstrated a clinically meaningful improvement in time to complete resolution of all 13 RSV symptoms compared to placebo, with an improvement of 6.7 days for patients with congestive heart failure, chronic obstructive pulmonary disease or age 75 or older, termed the HR3 population. Zelicapavir also showed an improvement in time to complete resolution on the 29-parameter total RiiQ™ symptom scale of 7.2 days for the HR3 population compared to placebo. The study met key secondary endpoints, including a reduction in hospitalization and antiviral effects. Previously, the Company reported positive data from a Phase 2 study in pediatric patients which demonstrated that treatment with zelicapavir was associated with shortened time to complete resolution of RSV symptoms. Overall, zelicapavir has been dosed in more than 700 people to date and continues to be well-tolerated with a favorable safety profile. Enanta presented data on zelicapavir at the European Society of Clinical Microbiology & Infectious Diseases (ESCMID) Global 2026 which was held April 17-21, 2026, in Munich, Germany. The poster and presentation are available on the Company’s website here. Enanta will present an oral presentation highlighting zelicapavir at the American Thoracic Society (ATS) International Conference 2026, being held May 15-20, 2026, in Orlando, Florida. Enanta continues to conduct enabling activities for a pivotal study of zelicapavir in high-risk patients with RSV, including engaging with the FDA on the registrational development path. The Company plans to provide an update on the study design and development path in the second quarter of 2026. In parallel, Enanta is exploring potential business development opportunities related to its RSV program. Enanta’s second RSV candidate, EDP-323, can be used alone or in combination with other agents, such as zelicapavir, to potentially broaden the treatment window or addressable patient populations. Previously, the Company reported positive results from a Phase 2a challenge study of healthy adults infected with RSV, in which treatment with EDP-323 achieved highly statistically significant reductions in both viral load and clinical symptoms compared to placebo. Immunology Enanta’s immunology pipeline is focused on designing and developing highly potent and selective oral inhibitors for the treatment of inflammatory diseases, by targeting key drivers of the type 2 immune response. Enanta’s lead immunology program, EDP-978, is a potent and selective once-daily oral KIT inhibitor in development for the treatment of chronic urticaria and potentially other mast cell-mediated diseases. In April, the Company announced the first participant was dosed in a randomized, double-blind, placebo-controlled, first-in-human Phase 1 clinical trial. The trial is expected to enroll approximately 98 healthy adult volunteers ranging in age from 18 to 65 years old to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics, including serum tryptase, of EDP-978. The trial includes a single ascending dose phase, with a two-part food-effect cohort, and a multiple ascending dose phase with a 14-day treatment period. The Company expects to report topline data from the trial in the fourth quarter of 2026. Enanta presented two posters featuring pre-clinical data related to EDP-978 at the American Academy of Allergy, Asthma & Immunology (AAAAI) 2026 Annual Meeting which was held February 27-March 2, 2026. The posters are available on the Company’s website here. Enanta’s second immunology program EPS-3903, is a novel, potent, and selective oral STAT6 inhibitor, in development for the treatment of atopic dermatitis and other diseases currently treated by dupilumab. The Company is currently performing scale-up and IND enabling activities and is targeting an IND filing in the second half of 2026. Enanta presented four posters highlighting pre-clinical data related to EPS-3903 at IMMUNOLOGY2026TM, hosted by the American Association of Immunologists (AAI), held April 15-19, 2026. The posters are available on the Company’s website here. Enanta will present two posters highlighting data on EPS-3903 at the ATS International Conference 2026, being held May 15-20, 2026, in Orlando, Florida. Enanta’s third immunology program targets MRGPRX2, a non-canonical G-Protein-Coupled-Receptor (GPCR) expressed predominantly on mast cells, as well as peripheral neurons. Inhibiting MRGPRX2 may have potential to address multiple chronic inflammatory diseases including urticaria, asthma, prurigo nodularis and others, as well as migraine. Currently, the Company is evaluating multiple compounds in pre-clinical studies and expects to select a development candidate in the second half of 2026. Corporate Today, the United States Court of Appeals for the Federal Circuit held oral arguments in Enanta’s lawsuit against Pfizer Inc., seeking damages for infringement of U.S. Patent No. 11,358,953 in the manufacture, use and sale of Pfizer’s COVID-19 antiviral, PAXLOVID® (nirmatrelvir tablets; ritonavir tablets). Based on the current schedule, Enanta anticipates a decision on the appeal from the Federal Circuit by the end of September 2026. A hearing for the patent infringement action against Pfizer Inc. and certain of its subsidiaries in the Unified Patent Court (UPC) of the European Union, and Pfizer’s counterclaim for revocation, has been scheduled for September 29, 2026. Enanta expects a decision from the UPC within weeks after the hearing. Enanta plans to issue its fiscal third quarter financial results press release on August 10, 2026. About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs for viral infections and immunological diseases. In virology, Enanta’s clinical programs are focused on the development of first-in-disease and best-in-disease treatments for respiratory syncytial virus (RSV). The Company’s immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, with KIT, STAT6 and MRGPRX2 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of one of the leading treatment regimens for curing hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information. Forward Looking Statements This press release contains forward-looking statements, including statements with respect to the timeline and prospects for advancement of Enanta’s clinical programs in RSV and KIT inhibition and its pre-clinical immunology programs, including its programs targeting STAT6 and MRGPRX2 inhibition, as well as statements regarding Enanta’s ongoing litigation matters. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and management’s beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors and risks that may affect actual results include: the impact of development, regulatory and marketing efforts of others with respect to vaccines and competitive treatments for RSV; the discovery and development risks of Enanta’s programs in virology and immunology; Enanta’s limited clinical development experience; Enanta’s ability to partner its RSV or other programs; Enanta’s need to attract and retain senior management and key research and development personnel; Enanta’s need to obtain and maintain patent protection for its product candidates and avoid potential infringement of the intellectual property rights of others; the timing and outcome of Enanta’s ongoing litigation matters; and other risk factors described or referred to in "Risk Factors" in Enanta’s Form 10-K for the fiscal year-ended September 30, 2025, and any other periodic reports filed more recently with the Securities and Exchange Commission. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Enanta undertakes no obligation to update or revise these statements, except as may be required by law. Tables to Follow View source version on businesswire.com: https://www.businesswire.com/news/home/20260511989798/en/ Contacts Media and Investors Contact: Jennifer Viera [email protected]

Conducting Phase 3 Enabling Activities, Including Discussions with U.S. Food & Drug Administration (FDA), for Zelicapavir, an N-Protein Inhibitor in Development to Treat Respiratory Syncytial Virus (RSV) Introduced New Immunology Program Focused on MRGPRX2 Inhibition; On Track to Select a Development Candidate in 2H 2026 On Track to File an Investigational New Drug Application (IND) in 1Q 2026 and Report Phase 1 Data in 4Q 2026 for EDP-978, an Oral, Once-Daily KIT Inhibitor Clinical Candidate On Track to File an IND in 2H 2026 for EPS-3903, an Oral, Once-Daily STAT6 Inhibitor Development Candidate Strong Financial Position of $241.9 Million Supported by Continuing Retained Royalties, with Cash Runway Expected to Fund Operations into Fiscal 2029 WATERTOWN, Mass., February 09, 2026--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today reported financial results for its fiscal first quarter ended December 31, 2025. "Enanta entered the year with significant momentum, advancing our leading RSV treatment portfolio with preparation for a Phase 3 study and expanding our immunology pipeline with the introduction of our third program focused on developing oral MRGPRX2 inhibitors for type 2 immune driven diseases," said Jay R. Luly, Ph.D., President and Chief Executive Officer at Enanta Pharmaceuticals. "With zelicapavir demonstrating clinically meaningful benefits in pediatric and high‑risk adult RSV studies and EDP‑323 showing promise not only in treatment, but also in post‑exposure prophylaxis, we are driving forward first-in-disease programs that have the potential to fundamentally change RSV patient care. In tandem, we are further building out our immunology portfolio, which now includes highly selective inhibitors of KIT, STAT6 and MRGPRX2." Fiscal First Quarter Ended December 31, 2025 Financial Results Total revenue for the three months ended December 31, 2025 was $18.6 million and consisted of royalty revenue from worldwide net sales of MAVYRET®/MAVIRET® (glecaprevir/pibrentasvir), AbbVie’s eight-week treatment for chronic hepatitis C virus, compared to $17.0 million for the three months ended December 31, 2024. The increase in revenue is due to an increase in AbbVie’s product sales. A portion (54.5%) of Enanta’s ongoing royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET® is paid to OMERS, one of Canada’s largest defined benefit pension plans, pursuant to a royalty sale transaction affecting royalties earned after June 2023. For financial reporting purposes, the transaction was treated as debt, with the upfront purchase payment of $200.0 million recorded as a liability. Each quarter, Enanta records 100% of the royalty earned as revenue and then amortizes the debt liability proportionally as 54.5% of the cash royalty payments are paid to OMERS through June 30, 2032. This is subject to a cap of 1.42 times the purchase payment, after which point 100% of the cash royalty payments will be retained by Enanta. Interest expense was $3.1 million for the three months ended December 31, 2025, as compared to interest expense of $2.0 million for the three months ended December 31, 2024. Research and development expenses totaled $20.9 million for the three months ended December 31, 2025, compared to $27.7 million for the three months ended December 31, 2024. The decrease was due to a decrease in clinical trial expenses for Enanta’s RSV programs, partially offset by increased costs associated with the Company’s immunology programs. General and administrative expenses totaled $9.0 million for the three months ended December 31, 2025, compared to $12.8 million for the three months ended December 31, 2024. The decrease was due to a decrease in stock-based compensation expenses and a decrease in legal expenses related to the Company’s patent infringement lawsuits against Pfizer. Interest and investment income, net, totaled $2.4 million for the three months ended December 31, 2025, compared to $2.8 million for the three months ended December 31, 2024. The decrease in interest and investment income was due to lower interest rates year over year. Enanta recorded an income tax expense of less than $0.1 million for the three months ended December 31, 2025, compared to an income tax benefit of $0.4 million for the three months ended December 31, 2024. Enanta recorded interest earned on its federal income tax refund during the three months ended December 31, 2024, until the $33.8 million refund was received in April 2025. Net loss for the three months ended December 31, 2025 was $11.9 million, or a loss of $0.42 per diluted common share, compared to a net loss of $22.3 million, or a loss of $1.05 per diluted common share, for the corresponding period in 2024. Enanta’s cash, cash equivalents and short-term and long-term marketable securities totaled $241.9 million at December 31, 2025. Enanta expects that its current cash, cash equivalents and marketable securities, as well as its retained portion of future royalty revenue, will be sufficient to meet the anticipated cash requirements of its existing business and development programs into fiscal 2029. Virology Enanta’s virology pipeline includes the leading portfolio in development for oral RSV treatment, consisting of zelicapavir, Enanta’s lead, once-daily N-protein inhibitor, and EDP-323, its once-daily L-protein inhibitor, both of which received Fast Track designation from the U.S. Food and Drug Administration. In September 2025, Enanta announced positive data from RSVHR, a Phase 2b study evaluating zelicapavir in a high-risk adult outpatient population, including the elderly and those with asthma, chronic obstructive pulmonary disease, or congestive heart failure. A clinically meaningful improvement in time to complete resolution of all 13 RSV symptoms was observed for zelicapavir compared to placebo, with an improvement of 6.7 days for patients with congestive heart failure, chronic obstructive pulmonary disease or age 75 or older, termed the HR3 population. Zelicapavir also showed an improvement in time to complete resolution on the 29-parameter total RiiQ™ symptom scale of 7.2 days for the HR3 population compared to placebo. The study met key secondary endpoints, including a reduction in hospitalization and antiviral effects. Zelicapavir has been dosed in more than 700 people to date and continues to be well-tolerated with a favorable safety profile. Enanta continues to conduct Phase 3 enabling activities, with the goal of aligning with the FDA in the second quarter of 2026 on an adult Phase 3 trial design and overall registration path. In parallel, Enanta is exploring potential business development opportunities related to its RSV program. Enanta’s second RSV candidate, EDP-323, can be used alone or in combination with other agents, such as zelicapavir, to potentially broaden the treatment window or addressable patient populations. In October 2025, the Company presented data on a post-exposure prophylaxis analysis performed in subjects who were not infected by Day 5 after RSV exposure in the previously disclosed EDP-323 Phase 2a human challenge study. The data showed the potential for EDP-323 to be effective in preventing RSV infection when initiated up to five days after RSV exposure, building on the previously reported EDP-323 challenge study treatment data. Immunology Enanta’s immunology pipeline is focused on designing and developing highly potent and selective oral inhibitors for the treatment of inflammatory diseases, by targeting key drivers of the type 2 immune response. In January 2026, Enanta announced its third immunology program targeting MRGPRX2, a non-canonical G-Protein-Coupled-Receptor (GPCR) expressed predominantly on mast cells. Inhibiting MRGPRX2 may have potential to address multiple chronic inflammatory diseases including urticaria, asthma, prurigo nodularis and others. Currently, Enanta is advancing novel, potent and selective oral inhibitors of MRGPRX2. The Company’s prototype MRGPRX2 inhibitors exhibit potent inhibition in vitro and in vivo. Specifically, they demonstrate MRGPRX2 inhibition with nanomolar potency (EC50 of 1-2nM) in cellular assays and prevent skin mast cell activation in humanized MRGPRX2 mouse models. Further, the Company’s MRGPRX2 prototype inhibitors show potent activity across multiple MRGPRX2 agonists. These prototypes are highly selective for MRGPRX2 versus other GPCRs, and show favorable in vitro and in vivo ADME properties supporting once daily dosing. Enanta continues to evaluate multiple compounds in preclinical studies and expects to select a development candidate in the second half of 2026. Enanta recently selected EDP-978, a novel, potent and selective oral KIT inhibitor, as its clinical candidate for the treatment of chronic spontaneous urticaria and potentially other mast cell driven diseases. EDP-978 demonstrates nanomolar potency in both binding and cellular assays, sub-nanomolar activity in vivo, and high selectivity for KIT versus other kinases. EDP-978 also exhibits favorable in vitro and in vivo ADME properties preclinically. The Company is on track to submit an IND in the first quarter, with topline Phase 1 data expected in the fourth quarter of 2026. Enanta plans to have two presentations of pre-clinical data related to its KIT program at the 2026 American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting taking place February 27 to March 2, 2026. In November 2025, Enanta nominated EPS-3903, a novel, potent and selective oral STAT6 inhibitor, as its lead development candidate for the treatment of atopic dermatitis and other diseases currently treated by dupilumab. Preclinical data show EPS-3903 exhibits nanomolar activity in binding and cellular assays and high selectivity for STAT6. Importantly, EPS-3903 shows rapid, continuous and complete (>90%) inhibition of phosphorylated STAT6 (pSTAT6) after oral dosing in mice. Further, EPS-3903 demonstrates efficacy comparable to dupilumab in multiple disease models. Specifically, in a house dust mite asthma model, treatment with EPS-3903 results in complete (>90%) inhibition of lung pSTAT6 and decreased inflammation comparable to dupilumab, including clinically relevant biomarkers of eosinophils and TARC in the lung and serum IgE. Additionally, in an MC903 atopic dermatitis mouse model, EPS-3903 demonstrates efficacy comparable to dupilumab, with complete (>90%) inhibition of pSTAT6 in the skin and spleen, as well as a robust decrease in serum IgE. EPS-3903 has favorable in vitro and in vivo ADME properties with once-daily dosing potential. The Company is currently performing scale-up and IND enabling activities and targeting an IND filing in the second half of 2026. Enanta plans to have four presentations of pre-clinical data related to its STAT6 program at Immunology2026TM, held by the American Association of Immunologists (AAI), taking place April 15-19, 2026. Corporate Enanta plans to issue its fiscal second quarter financial results press release on May 11, 2026. About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs for viral infections and immunological diseases. Enanta’s clinical programs are currently focused on respiratory syncytial virus (RSV) and its earlier-stage immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, with KIT, STAT6 and MRGPRX2 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of one of the leading treatment regimens for curing hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information. Forward Looking Statements This press release contains forward-looking statements, including statements with respect to the timeline and prospects for advancement of Enanta’s clinical programs in RSV and its preclinical immunology programs, including its programs targeting KIT, STAT6 and MRGPRX2 inhibition. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and management’s beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors and risks that may affect actual results include: the impact of development, regulatory and marketing efforts of others with respect to vaccines and competitive treatments for RSV; the discovery and development risks of Enanta’s programs in virology and immunology; Enanta’s limited clinical development experience; Enanta’s ability to partner its RSV or other programs; Enanta’s need to attract and retain senior management and key research and development personnel; Enanta’s need to obtain and maintain patent protection for its product candidates and avoid potential infringement of the intellectual property rights of others; and other risk factors described or referred to in "Risk Factors" in Enanta’s Form 10-K for the fiscal year-ended September 30, 2025, and any other periodic reports filed more recently with the Securities and Exchange Commission. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Enanta undertakes no obligation to update or revise these statements, except as may be required by law. Tables to Follow View source version on businesswire.com: https://www.businesswire.com/news/home/20260209293558/en/ Contacts Media and Investors Contact: Jennifer Viera 617-744-3848 [email protected]

Announces EPS-3903, an Oral, Once-Daily STAT6 Inhibitor Development Candidate with Rapid, Continuous and Complete (>90%) In Vivo pSTAT6 Suppression and Efficacy Comparable to Dupilumab in Asthma and Atopic Dermatitis Disease Models Announces EDP-978, an Oral, Once-Daily KIT Inhibitor Clinical Candidate with Plans to File an Investigational New Drug Application in Q1 2026 Reported Positive Topline Data for RSVHR, a Phase 2b Study of Zelicapavir in High-Risk Adults Infected with Respiratory Syncytial Virus (RSV) Strong Financial Position Ending Fiscal 2025 with $188.9 Million in Cash, Cash Equivalents and Marketable Securities; Further Strengthened by Gross Proceeds of $74.8 Million Upsized Public Offering in October 2025 and Continuing Retained Royalties, Expected to Fund Operations into Fiscal 2029 WATERTOWN, Mass., November 17, 2025--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today reported financial results for its fiscal fourth quarter and year-ended September 30, 2025. "This past quarter marked a pivotal period for Enanta, with significant progress across our virology and immunology programs, highlighted by positive topline data from the RSVHR study, our Phase 2b clinical trial in high-risk adults infected with RSV. These Phase 3-enabling results underscore zelicapavir’s ability to meaningfully reduce the duration of RSV symptoms and represent the first time an antiviral treatment demonstrated a clinically meaningful benefit in high-risk adult outpatients with RSV," said Jay R. Luly, Ph.D., President and Chief Executive Officer at Enanta Pharmaceuticals. "In parallel, we reached an important milestone for our oral STAT6 program with the selection of EPS-3903 as our lead development candidate for the treatment of type 2 immune-driven diseases. This novel, potent and selective inhibitor has demonstrated rapid, continuous and complete pSTAT6 suppression of greater than 90%, and efficacy comparable to dupilumab in multiple asthma and atopic dermatitis disease mouse models after oral dosing. We look forward to filing an Investigational New Drug application for this program in the second half of 2026. Additionally, we have nominated EDP-978 as our oral, once-daily KIT inhibitor clinical candidate for the treatment of mast-cell driven diseases, with plans to file an IND in the first quarter of 2026. Taken together, this progress underscores our commitment to developing small molecule treatments for immunological diseases." Fiscal Fourth Quarter and Year-Ended September 30, 2025 Financial Results Total revenue was $15.1 million for the three months ended September 30, 2025, which consisted of royalty revenue derived from worldwide net sales of AbbVie’s hepatitis C virus (HCV) regimen MAVYRET®/MAVIRET®, compared to $14.6 million for the three months ended September 30, 2024. The increase in the quarter is due to an increase in AbbVie’s sales of MAVYRET®/MAVIRET®. For the twelve months ended September 30, 2025, total revenue was $65.3 million compared to $67.6 million for the same period in 2024. The decrease in year-over-year revenue is due to a decline in AbbVie’s sales of MAVYRET®/MAVIRET® in the first nine months of fiscal 2025. A portion (54.5%) of Enanta’s ongoing royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET® is paid to OMERS, one of Canada’s largest defined benefit pension plans, pursuant to a royalty sale transaction affecting royalties earned after June 2023. For financial reporting purposes, the transaction was treated as debt, with the upfront purchase payment of $200.0 million recorded as a liability. Each quarter, Enanta records 100% of the royalty earned as revenue and then amortizes the debt liability proportionally as 54.5% of the cash royalty payments are paid to OMERS through June 30, 2032, subject to a cap of 1.42 times the purchase payment, after which point 100% of the cash royalty payments will be retained by Enanta. Interest expense was $2.4 million for the three months ended September 30, 2025 and $7.7 million for the twelve months ended September 30, 2025. This compares to interest expense of $2.6 million for the three months ended September 30, 2024 and $10.9 million for the twelve months ended September 30, 2024. Research and development expenses were $23.8 million for the three months ended September 30, 2025, compared to $30.8 million for the three months ended September 30, 2024. For the twelve months ended September 30, 2025, research and development expenses were $106.7 million compared to $131.5 million for the same period in 2024. The decrease in the quarter and year-over-year research and development expenses is primarily due to a decrease in expenses as a result of the timing of clinical trials in Enanta’s RSV programs, partially offset by increased costs associated with the Company’s immunology programs. General and administrative expenses totaled $9.7 million for the three months ended September 30, 2025, compared to $13.7 million for the three months ended September 30, 2024. For the twelve months ended September 30, 2025, general and administrative expenses were $43.9 million compared to $57.9 million in 2024. The decrease in the quarter and year-over-year general and administrative expenses is due to a decrease in legal expenses related to the Company’s patent infringement lawsuit against Pfizer and a decrease in stock-based compensation expenses. Interest and investment income, net, totaled $2.1 million for the three months ended September 30, 2025, compared to $3.2 million for the three months ended September 30, 2024. For the twelve months ended September 30, 2025, interest and investment income, net, totaled $9.5 million compared to $14.8 million in 2024. The decrease in the quarter and year-over-year interest and investment income was primarily due to lower cash and lower income on the investment balances. Enanta recorded an income tax expense of less than $0.1 million for the three months ended September 30, 2025, compared to an income tax benefit of $0.4 million for the three months ended September 30, 2024. Enanta recorded an income tax benefit of $1.7 million for each of the twelve-month periods ended September 30, 2024 and 2025. Enanta recorded interest earned on its federal income tax refund during fiscal 2024 and 2025 until the $33.8 million refund was received in April 2025. Net loss for the three months ended September 30, 2025, was $18.7 million, or a loss of $0.87 per diluted common share, compared to a net loss of $28.8 million, or a loss of $1.36 per diluted common share, for the corresponding period in 2024. For the twelve months ended September 30, 2025, net loss was $81.9 million, or a loss of $3.84 per diluted common share, compared to a net loss of $116.0 million, or a loss of $5.48 per diluted common share for the corresponding period in 2024. Enanta’s cash, cash equivalents and marketable securities totaled $188.9 million at September 30, 2025. Enanta expects that its current cash, cash equivalents and marketable securities, as well as cash flows from its retained portion of future royalty revenue and proceeds from its October 2025 public offering, will be sufficient to meet the anticipated cash requirements of its existing business and development programs into fiscal 2029. Virology Enanta’s virology pipeline includes the leading portfolio in development for RSV treatment, consisting of zelicapavir and EDP-323, both of which received Fast Track designation from the U.S. Food and Drug Administration. In September, Enanta reported data on zelicapavir, an oral, once-daily RSV N-protein inhibitor, which was evaluated in RSVHR, a Phase 2b, randomized, double-blind, placebo-controlled study in adults with RSV infection who were at high risk of complications. This includes patients older than 65 years and those with congestive heart failure, chronic obstructive pulmonary disease or asthma. In the RSVHR study, a clinically meaningful improvement in time to complete resolution of all 13 RSV symptoms was observed for zelicapavir compared to placebo, with a benefit of 2.2 days for the overall efficacy population and 6.7 days for patients with congestive heart failure, chronic obstructive pulmonary disease, or age 75 years or older, termed the HR3 population, which comprised the majority (81%) of the efficacy population. Zelicapavir also showed an improvement in time to complete resolution on the 29-parameter total RiiQ™ symptom scale of 3.6 days for the efficacy population and 7.2 days for the HR3 population compared to placebo. Additionally, there was a 3.0-day faster time to complete resolution of lower respiratory tract disease (LRTD) symptoms in the HR3 population; however, no effect was observed on the time to resolution of the LRTD subset of four symptoms to mild, which was the primary endpoint. The study met the secondary endpoint of time to improvement in the Patient Global Impression of Severity (PGI-S) score, with a statistically significant 2-day faster resolution with zelicapavir compared to placebo. Importantly, a lower hospitalization rate was observed for patients treated with zelicapavir compared to placebo. The study met key secondary virology endpoints showing a robust antiviral effect. Zelicapavir demonstrated a favorable safety profile and was well-tolerated in the study. In October, the Company presented data at the Infectious Diseases Society of America (IDSA) 2025 Conference (IDWeek™) highlighting its previously reported positive results from the Phase 2 study of zelicapavir in pediatric patients, including new data demonstrating that treatment with zelicapavir is associated with shortened time to complete resolution of RSV symptoms (defined as absent and discharged from hospital). A post-hoc analysis of time to complete resolution of symptoms showed an estimated Kaplan-Meier median of 6.99 days for zelicapavir versus 8.60 days for placebo. Similarly, an analysis of sustained resolution (defined as absent and remaining absent at all subsequent time points and discharged from hospital) resulted in 6.99 days for zelicapavir versus 10.68 days for placebo. The poster can be found on the Company’s website here. Enanta’s second RSV candidate is EDP-323, an oral, once-daily RSV L-protein inhibitor, which can be used alone or in combination with other agents, such as zelicapavir, to potentially broaden the treatment window or addressable patient populations. In October, the Company presented data at IDWeek™ on the previously disclosed Phase 2a human challenge study of EDP-323. A post-exposure prophylaxis (PEP) analysis was performed in subjects who were not infected by Day 5 after RSV exposure. In this population, 68 RSV-exposed, susceptible subjects were randomized to receive EDP-323 (low dose n=24, high dose n=21) or placebo (n=23). Of these subjects, 26% (6/23) of those who received placebo became infected versus 0% (0/45) of EDP-323 recipients (p<0.001). Evaluated separately, the two EDP-323 dosing groups’ PEP effects were statistically significant (low dose p=0.009, high dose p=0.022) versus placebo. The poster can be found on the Company’s website here. An oral presentation of the EDP-323 challenge study was also featured at IDWeek™. In new data on clinical symptoms, which were assessed once-daily using the Respiratory Infection Intensity and Impact Questionnaire (RiiQ™), participants showed rapid (within the first 24 hours) and statistically significant improvements in RiiQ™ RSV symptoms and viral load after EDP-323 dosing. Compared to placebo, there were 73% (p=0.0012), 61% (p=0.0010), and 67% (p<0.0001) RiiQ™ total symptom score AUC reductions in 200mg, 600mg, and EDP-323 pooled recipients respectively. The presentation can be found on the Company’s website here. Immunology Enanta’s immunology pipeline is focused on designing and developing highly potent and selective oral inhibitors for the treatment of inflammatory diseases, by targeting key drivers of the type 2 immune response. Enanta nominated EPS-3903, a novel, potent and selective oral STAT6 inhibitor, as its lead development candidate for the treatment of atopic dermatitis and other diseases currently treated by dupilumab. Preclinical data show EPS-3903 exhibited potent nanomolar activity in binding and cellular assays and was highly selective for STAT6. Importantly, EPS-3903 showed rapid, continuous and complete (>90%) inhibition of phosphorylated STAT6 (pSTAT6) after oral dosing in mice. Further, EPS-3903 demonstrated efficacy comparable to dupilumab in multiple disease models. Specifically, in a house dust mite asthma model, EPS-3903 resulted in complete (>90%) inhibition of lung pSTAT6 and decreased inflammation comparable to dupilumab, including clinically relevant biomarkers of eosinophils and TARC in the lung and serum IgE. Additionally, in an MC903 atopic dermatitis mouse model, EPS-3903 demonstrated efficacy comparable to dupilumab, with complete (>90%) inhibition of pSTAT6 in the skin and spleen, as well as a robust decrease in serum IgE. EPS-3903 had favorable in vitro and in vivo ADME properties with once-daily dosing potential. The Company is currently performing scale-up and IND enabling activities and targeting an IND filing in the second half of 2026. Enanta selected EDP-978, a novel, potent and selective oral KIT inhibitor, as its clinical candidate for the treatment of chronic spontaneous urticaria and potentially other mast cell driven diseases. EDP-978 demonstrated nanomolar potency in both binding and cellular assays, had sub-nanomolar activity in vivo, and high selectivity for KIT versus other kinases. EDP-978 also demonstrated good in vitro and in vivo ADME properties preclinically. The Company is on track to submit an IND in the first quarter of 2026. Enanta plans to expand its immunology pipeline with the introduction of a third program in the fourth quarter of this year. Corporate In August, Enanta filed a patent infringement action in the Unified Patent Court (UPC) of the European Union against Pfizer Inc. and certain of its subsidiaries. The suit seeks a determination of liability for infringement of European Patent No. EP 4 051 265 (the "’265 Patent") in connection with Pfizer’s manufacture, use, and sale of Paxlovid™ (nirmatrelvir tablets; ritonavir tablets) in the 18 EU member states participating in the UPC. Under UPC procedures, a hearing on the infringement action is expected within the UPC’s published 12-month target, with a decision rendered within weeks thereafter. In October, Enanta successfully closed an upsized underwritten public offering of 7,475,000 shares of common stock at $10.00 per share, including the full exercise of the underwriters’ option to purchase an additional 975,000 shares. The gross proceeds from the offering, before deducting underwriting discounts and commissions and other offering expenses, were approximately $74.8 million. Enanta plans to issue its fiscal first quarter 2026 financial results press release on February 9, 2026. About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs with an emphasis on indications in virology and immunology. Enanta’s clinical programs are currently focused on respiratory syncytial virus (RSV) and its earlier-stage immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, including KIT and STAT6 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of one of the leading treatment regimens for curing hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information. Forward Looking Statements This press release contains forward-looking statements, including statements with respect to the timeline and prospects for advancement of Enanta’s clinical programs in RSV and its preclinical immunology programs, including its programs targeting KIT and STAT6 inhibition. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and management’s beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors and risks that may affect actual results include: the impact of development, regulatory and marketing efforts of others with respect to vaccines and competitive treatments for RSV; the discovery and development risks of Enanta’s programs in virology and immunology; Enanta’s lack of clinical development experience; Enanta’s ability to partner its RSV or other programs; Enanta’s need to attract and retain senior management and key research and development personnel; Enanta’s need to obtain and maintain patent protection for its product candidates and avoid potential infringement of the intellectual property rights of others; and other risk factors described or referred to in "Risk Factors" in Enanta’s Form 10-K for the fiscal year-ended September 30, 2024, and any other periodic reports filed more recently with the Securities and Exchange Commission. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Enanta undertakes no obligation to update or revise these statements, except as may be required by law. Tables to Follow View source version on businesswire.com: https://www.businesswire.com/news/home/20251117823831/en/ Contacts Media and Investors: Jennifer Viera 617-744-3848 [email protected]

6.7-Day Improvement in Time to Complete Resolution of All RSV Symptoms for Patients with Chronic Obstructive Pulmonary Disease (COPD), Congestive Heart Failure (CHF), or Age ≥75 Statistically Significant Improvement in Patient Global Impression of Severity Score Lower Hospitalization Rate for Patients Treated with Zelicapavir (1.7%) vs. Placebo (5%) 4- to 5-Day Faster Median Time to Undetectable Viral Load with Zelicapavir vs. Placebo Management to Host Conference Call and Webcast Today at 8:30 a.m. ET WATERTOWN, Mass., September 29, 2025--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ: ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today announced positive topline data from RSVHR, a Phase 2b, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of zelicapavir in outpatient adults with acute RSV infection who are at high risk of complications including the elderly and/or those with congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD) or asthma. Zelicapavir, which received Fast Track designation from the U.S. Food and Drug Administration (FDA), is a novel N-protein inhibitor in development as a once-daily oral treatment for RSV. This proof-of-concept study was designed to understand the antiviral treatment effect on symptom endpoints measured using the Respiratory Infection Intensity and Impact Questionnaire (RiiQTM) patient reported outcome tool, as well as other clinically meaningful endpoints, in a broad patient population. A clinically meaningful improvement in time to complete resolution of all 13 RSV symptoms was observed for zelicapavir compared to placebo, with a benefit of 2.2 days for the overall efficacy population and 6.7 days for patients with CHF, COPD or age ≥75, termed the HR3 population, which comprised the majority (81%) of the efficacy population. Zelicapavir also showed an improvement in time to complete resolution on the 29-parameter total RiiQ™ symptom scale of 3.6 days for the efficacy population and 7.2 days for the HR3 population compared to placebo. Additionally, there was a 3.0-day faster time to complete resolution of lower respiratory tract disease (LRTD) symptoms in the HR3 population; however, no effect was observed on the time to resolution of the LRTD subset of four symptoms to mild, which was the primary endpoint. The study met the secondary endpoint of time to improvement in the Patient Global Impression of Severity (PGI-S) score, with a statistically significant 2-day faster resolution with zelicapavir compared to placebo. Importantly, a lower hospitalization rate was observed for patients treated with zelicapavir compared to placebo. The study met key secondary virology endpoints showing a robust antiviral effect. The study also showed that zelicapavir demonstrated a favorable safety profile and was well-tolerated. "We are highly encouraged by these results from our Phase 2b trial of zelicapavir in high-risk adults infected with RSV. This represents the first time an RSV antiviral treatment has demonstrated a clinically meaningful benefit in these high-risk adult outpatients. These data demonstrate the potential for zelicapavir to reduce the duration of RSV symptoms in high-risk adults who face an increased risk of hospitalization or death from this virus," said Scott T. Rottinghaus, M.D., Chief Medical Officer of Enanta Pharmaceuticals. "Building on the previously reported antiviral activity and favorable safety from our first-in-pediatrics study, we believe these findings continue to validate zelicapavir’s mechanism of action and reinforce its potential as a broadly effective, first-in-class RSV treatment. We believe the totality of these data provides strong rationale for further clinical advancement of zelicapavir. Importantly, we identified multiple potential registrational endpoints for a Phase 3 trial. We wish to thank the patients, family members and staff from all the sites who participated in the study. These results would not have been possible without their trust and involvement." "The patients enrolled in this study are particularly vulnerable to complications of RSV infection, often facing prolonged symptoms and heightened risk of hospitalization. Currently, there are no safe and effective antiviral RSV treatments available," said Mohamed Fayed, M.D., UCSF School of Medicine Regional Campus at Fresno (UCSF Fresno), a Principal Investigator in the study. "The RSV symptom benefit observed in this study is compelling and could significantly improve outcomes for high-risk adults." Zelicapavir RSVHR Phase 2b Study Topline Results RSVHR was a Phase 2b, randomized, double-blind, placebo-controlled study of RSV infection in non-hospitalized adults who are at high risk of complications, including the elderly and/or those with CHF, COPD or asthma. The proportion of patients aged 65-74 years or those with asthma was capped at 20% of the total population. Patients were enrolled within 72 hours of symptom onset and received 800mg of zelicapavir or placebo once daily for 5 days. The goal of this proof-of-concept, signal finding study was to inform the design of a Phase 3 trial, including populations and endpoints, as well as give an indication of a treatment effect on symptoms that could be confirmed in a larger registrational study. Symptoms were measured using the RiiQTM scale, which evaluates a total of 29 parameters, including 13 RSV symptoms, four of which are LRTD symptoms, and three other impact of disease components (daily activities, emotions, and social relationships). The primary endpoint evaluated the time to resolution of the LRTD subset of four symptoms to mild. Predefined analyses of complete resolution, defined by all symptoms absent, were also conducted. Multiple secondary endpoints, including all 13 RSV symptoms, total RiiQTM score, additional patient reported outcomes (e.g.; PGI-S), virology, safety, and hospitalization rate, were assessed. A total of 186 subjects received 800mg of zelicapavir (n=121) or placebo (n=65) orally, once daily for 5 days and were evaluated for 28 days thereafter (safety population). An efficacy population of 175 patients was further defined as those who were PCR positive for RSV at a central laboratory. An HR3 population was defined as those who had CHF, COPD, or age >75 (81% of the efficacy population). Demographics and baseline characteristics were balanced across treatment groups, with the majority of patients being enrolled within 48 hours of symptom onset. Zelicapavir demonstrated a favorable safety profile over the initial 5-day dosing period and through 28 days of follow-up, with adverse events (AEs) being similar between zelicapavir and placebo. No AEs led to treatment discontinuation or study withdrawal in the zelicapavir group. The majority of AEs were mild with diarrhea and asthma being the most common AEs on zelicapavir at 3.3% and 2.5%, respectively. A clinically meaningful improvement in time to complete resolution (defined as all symptoms absent) of all 13 RSV symptoms and in the total RiiQ™ was observed for zelicapavir compared to placebo in both the efficacy and HR3 populations. There was also a faster time to complete resolution of the subset of four LRTD symptoms in the HR3 population. Improvement in Time to Complete Resolution of Symptoms for Zelicapavir Compared to Placebo No effect was observed on the time to resolution of symptoms (defined as mild), including the primary endpoint of time to resolution of the LRTD subset of four symptoms in the efficacy population. Additionally, a statistically significant improvement in RiiQTM RSV 13-symptom score in the HR3 population at Days 9 (p=0.0403) and 14 (p=0.0247) was observed in a post-hoc analysis for zelicapavir compared to placebo. Furthermore, the study met a key secondary endpoint with zelicapavir treatment resulting in a statistically significant 2-day faster improvement in a Patient Global Impression of Severity (PGI-S) score compared to placebo in both the efficacy population (p=0.0446) and the HR3 population (p=0.0465). Importantly, a lower hospitalization rate was observed for patients treated with zelicapavir (1.7%) compared to placebo (5.0%). Blinded attribution by investigators judged none (0%) of the hospitalizations on zelicapavir and all (5.0%) of the hospitalization on placebo to be related to RSV. Post-hoc attribution suggested RSV-relatedness of 0.9% for the patients on zelicapavir compared to 5.0% on placebo. The study met key secondary virology endpoints showing a robust antiviral effect, with a statistically significantly greater proportion of zelicapavir patients having an undetectable viral load at the end of treatment compared with placebo. In the efficacy population undetectable viral load at the end of treatment was 23.5% vs. 10.0% in placebo (p=0.0198), and in the HR3 population was 23.9% vs. 10.0% in placebo (p=0.0292). Treatment with zelicapavir resulted in a 4- or 5-day faster median time to undetectable viral load and a 0.6 or 0.7 log decline in viral load at the end of treatment compared to placebo for the efficacy and HR3 populations, respectively. Full data from the study will be presented at a future medical conference or in a peer-reviewed publication. Conference Call and Webcast Information Enanta will host a conference call and webcast today at 8:30 a.m. ET. The live webcast can be accessed under "Events & Presentations" in the investors section of Enanta’s website. To participate by phone, please register for the call here. It is recommended that participants register a minimum of 15 minutes before the call. Once registered, participants will receive an email with the dial-in information. The archived webcast will be available on Enanta’s website for approximately 30 days following the event. About Zelicapavir Zelicapavir, Enanta’s lead N-protein inhibitor, is being developed for the treatment of RSV infection, and has been granted Fast Track designation by the U.S. Food and Drug Administration. Zelicapavir is a nanomolar inhibitor of both RSV-A and RSV-B activity. Zelicapavir is differentiated from RSV fusion inhibitors as the N-protein inhibitor targets the virus’ replication machinery and has demonstrated a high barrier to resistance in vitro. In preclinical studies, zelicapavir maintained antiviral potency across all clinical isolates tested and was active against viral variants resistant to other mechanisms. In a Phase 2 challenge study, zelicapavir achieved highly statistically significant (p<0.001) reductions in RSV viral load and clinical symptoms compared to placebo and was safe and well-tolerated, with infrequent adverse events. In a Phase 2 randomized, double-blind, placebo-controlled study of pediatric RSV patients aged 28 days to 3 years old, an antiviral effect was observed for the primary and secondary virology endpoints in the overall pooled efficacy population. The primary endpoint in Part 2 of the study, which focused on virology, showed a pronounced antiviral effect with a 1.4 log decline in viral load at Day 5 compared to placebo. Additionally, a rapid and robust virologic effect was observed in a prespecified subset of patients who were randomized within 3 days of symptom onset, with a 1.2 log decline in viral load at Day 5 compared to placebo. Zelicapavir has a favorable and consistent safety profile in over 600 people exposed to date. About Respiratory Syncytial Virus in Older Adults RSV is a common respiratory virus that infects the lungs and respiratory tract. Older adults are at significantly increased risk of severe illness due to the natural weakening of the immune system with age. This risk is even greater for individuals with underlying health conditions such as chronic obstructive pulmonary disease (COPD), asthma, or chronic heart failure. Those conditions can also be exacerbated by RSV, potentially lead to serious complications such as pneumonia, hospitalization, or even death. For adults aged 65 years and older, annually there are approximately 1.7 million medically attended visits, with 120K emergency room visits and between 160K-177K hospitalizations.1,2 About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs with an emphasis on indications in virology and immunology. Enanta’s clinical programs are currently focused on respiratory syncytial virus (RSV) and its earlier-stage immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, including KIT and STAT6 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of one of the leading treatment regimens for curing chronic and acute hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information. Forward Looking Statements This press release contains forward-looking statements, including with respect to the prospects for further development and advancement of zelicapavir for the treatment of RSV. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and management’s beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors and risks that may affect actual results include: the development risks of early stage discovery efforts in the disease areas in Enanta’s research and development pipeline, such as RSV; the impact of development, regulatory and marketing efforts of others with respect to competitive treatments for RSV; Enanta’s limited clinical development experience; Enanta’s need to attract and retain senior management and key scientific personnel; Enanta’s need to obtain and maintain patent protection for its product candidates and avoid potential infringement of the intellectual property rights of others; and other risk factors described or referred to in "Risk Factors" in Enanta’s most recent Annual Report on Form 10-K for the fiscal year ended September 30, 2024 and other periodic reports filed more recently with the Securities and Exchange Commission. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. All forward-looking statements contained in this release speak only as of the date on which they were made and are based on management’s assumptions and estimates as of such date. Enanta undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law. View source version on businesswire.com: https://www.businesswire.com/news/home/20250929135632/en/ Contacts Media and Investors Contact Jennifer Viera 617-744-3848 [email protected]

On Track to Report Topline Data for RSVHR, a Phase 2 Study of Zelicapavir in High-Risk Adults Infected with Respiratory Syncytial Virus (RSV), in September On Track to Select a STAT6 Development Candidate in 2H 2025 Conducting IND Enabling Studies of EPS-1421, an Oral KIT Inhibitor Candidate, in Development for the Treatment of Chronic Spontaneous Urticaria and Other Mast Cell Driven Diseases Operations Supported by Cash and Marketable Securities Totaling $204.1 Million at June 30, 2025, as well as Continuing Retained Royalties WATERTOWN, Mass., August 11, 2025--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and immunological diseases, today reported financial results for its fiscal third quarter ended June 30, 2025. "This past quarter we continued to make steady progress across our pipeline, marked by the completion of enrollment in the RSVHR trial, a proof-of-concept study of zelicapavir in high-risk adults infected with RSV. These patients face a heightened risk of serious illness from RSV, but currently there are no approved antiviral treatments available. We look forward to reporting topline data for the RSVHR trial in September," said Jay. R. Luly, Ph.D., President and Chief Executive Officer at Enanta Pharmaceuticals. "We have continued to execute on advancing multiple immunology programs including high-impact targets, KIT and STAT6. We are progressing IND-enabling studies for our oral KIT inhibitor, EPS-1421, and expect to select a lead development candidate for our oral STAT6 inhibitor program in the second half of this year. We plan to build on our emerging pipeline of highly selective and potent oral inhibitors for the treatment of inflammatory diseases with the announcement of a third program later this year." Fiscal Third Quarter Ended June 30, 2025 Financial Results Total revenue for the three months ended June 30, 2025 was $18.3 million and consisted of royalty revenue from worldwide net sales of AbbVie’s hepatitis C virus (HCV) regimen MAVYRET®/MAVIRET® (glecaprevir/pibrentasvir), compared to $18.0 million for the three months ended June 30, 2024. A portion (54.5%) of Enanta’s ongoing royalty revenue from AbbVie’s net sales of MAVYRET®/MAVIRET® is paid to OMERS, one of Canada’s largest defined benefit pension plans, pursuant to a royalty sale transaction affecting royalties earned after June 2023. For financial reporting purposes, the transaction was treated as debt, with the upfront purchase payment of $200.0 million recorded as a liability. Each quarter, Enanta records 100% of the royalty earned as revenue and then amortizes the debt liability proportionally as 54.5% of the cash royalty payments are paid to OMERS through June 30, 2032 subject to a cap of 1.42 times the purchase payment, after which point 100% of the cash royalty payments will be retained by Enanta. Interest expense from the royalty sale for the three months ended June 30, 2025 was $1.6 million, compared to $2.4 million for the three months ended June 30, 2024. Research and development expenses totaled $27.2 million for the three months ended June 30, 2025, compared to $28.7 million for the three months ended June 30, 2024. The decrease was primarily due to a decrease in expenses as a result of the timing of clinical trials in the Company’s RSV programs. General and administrative expenses totaled $10.0 million for the three months ended June 30, 2025, compared to $13.4 million for the three months ended June 30, 2024. The decrease was primarily due to a decrease in legal expenses related to the Company’s patent infringement lawsuit against Pfizer. Interest and investment income, net, totaled $2.3 million for the three months ended June 30, 2025, compared to $3.5 million for the three months ended June 30, 2024. The decrease was due to lower cash and investment balances year-over-year. Enanta recorded income tax expense of less than $0.1 million for the three months ended June 30, 2025, compared to an income tax benefit of $0.4 million for the three months ended June 30, 2024. The Company received its federal income tax refund of $33.8 million in April 2025. Net loss for the three months ended June 30, 2025 was $18.3 million, or a loss of $0.85 per diluted common share, compared to a net loss of $22.7 million, or a loss of $1.07 per diluted common share, for the corresponding period in 2024. Enanta’s cash, cash equivalents and short-term marketable securities totaled $204.1 million at June 30, 2025. Enanta expects that its current cash, cash equivalents and marketable securities and its continuing portion of cash from future royalty revenue, should be sufficient to meet the anticipated cash requirements of its existing business and development programs into fiscal year 2028. Virology Enanta’s virology pipeline is focused on developing oral antiviral treatments for serious infections, including the leading RSV therapeutic portfolio, consisting of zelicapavir and EDP-323, both of which received Fast Track designation from the U.S. Food and Drug Administration (FDA). The Company will evaluate potential partnership opportunities to further develop these RSV assets. Zelicapavir, a potent, oral N-protein inhibitor, is currently being evaluated in RSVHR, a Phase 2b, randomized, double-blind, placebo-controlled study in adults with RSV infection who are at high risk of complications. This includes patients over age 65 years and/or those with congestive heart failure, chronic obstructive pulmonary disease or asthma. Enrollment in RSVHR is complete with 186 patients and the Company is on track to report topline data in September. In May, the Company presented data at the European Society for Paediatric Infectious Diseases (ESPID) 2025 Conference highlighting its previously reported positive results from the Phase 2 study of zelicapavir in pediatric patients, including new data on population PK/PD and shortened time to viral load negativity. The presentation can be found on the Company’s website. EDP-323 is a potent, oral RSV L-protein inhibitor, which can be used alone or in combination with other agents, such as zelicapavir, to potentially broaden the treatment window or addressable patient populations. In April, in an oral presentation at the European Society of Clinical Microbiology & Infectious Diseases Global 2025 Conference (ESCMID), Enanta presented results from its previously disclosed Phase 2a human challenge study of EDP-323 and highlighted new data on reduced respiratory mucus production. The presentation can be found on the Company’s website. Immunology Enanta’s immunology pipeline is focused on designing and developing highly potent and selective oral inhibitors for the treatment of inflammatory diseases, by targeting key drivers of the type 2 immune response. IND enabling studies and scale-up activities are ongoing for EPS-1421, a novel, potent, and selective oral inhibitor of KIT. EPS-1421 is being developed to treat chronic spontaneous urticaria and other mast cell driven indications by depleting mast cells through KIT inhibition, thereby addressing a primary driver of these diseases. EPS-1421 inhibits KIT with nanomolar potency in both binding and cellular assays, has sub-nanomolar activity in vivo, is highly selective for KIT versus other kinases, and has demonstrated good in vitro and in vivo ADME properties preclinically. Enanta remains on track to select a STAT6 inhibitor development candidate in the second half of 2025. Preclinical data show Enanta’s prototype oral STAT6 inhibitors exhibit potent nanomolar activity and are highly selective for STAT6. Importantly, the prototype oral inhibitors resulted in rapid and complete inhibition of IL-4 induced phosphorylated STAT6 after a single oral dose in a mouse, demonstrating in vivo target engagement. Further, the prototypes reduced STAT6 activation and suppressed a type 2 inflammatory profile in an acute OVA asthma model. Finally, the prototypes display favorable in vitro and in vivo ADME properties with once-daily dosing potential. Enanta plans to expand its immunology pipeline with the introduction of a third program in 2025. Corporate Enanta’s Partner AbbVie received FDA approval of an expanded indication for MAVYRET® (glecaprevir/pibrentasvir) as the first and only treatment for people with acute HCV. Enanta plans to issue its fiscal fourth quarter and year-end financial results press release on November 17, 2025. About Enanta Pharmaceuticals, Inc. Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs with an emphasis on indications in virology and immunology. Enanta’s clinical programs are currently focused on respiratory syncytial virus (RSV) and its earlier-stage immunology pipeline aims to develop treatments for inflammatory diseases by targeting key drivers of the type 2 immune response, including KIT and STAT6 inhibition. Glecaprevir, a protease inhibitor discovered by Enanta, is part of one of the leading treatment regimens for curing hepatitis C virus (HCV) infection and is sold by AbbVie in numerous countries under the tradenames MAVYRET® (U.S.) and MAVIRET® (ex-U.S.) (glecaprevir/pibrentasvir). A portion of Enanta’s royalties from HCV products developed under its collaboration with AbbVie contribute ongoing funding to Enanta’s operations. Please visit www.enanta.com for more information. Forward Looking Statements This press release contains forward-looking statements, including statements with respect to the timeline and prospects for advancement of Enanta’s clinical programs in RSV and its preclinical immunology programs, including its programs targeting KIT and STAT6 inhibition. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and management’s beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors and risks that may affect actual results include: the impact of development, regulatory and marketing efforts of others with respect to vaccines and competitive treatments for RSV; the discovery and development risks of Enanta’s programs in virology and immunology; Enanta’s lack of clinical development experience; Enanta’s ability to partner its RSV or other programs; Enanta’s need to attract and retain senior management and key research and development personnel; Enanta’s need to obtain and maintain patent protection for its product candidates and avoid potential infringement of the intellectual property rights of others; and other risk factors described or referred to in "Risk Factors" in Enanta’s Form 10-K for the fiscal year-ended September 30, 2024, and any other periodic reports filed more recently with the Securities and Exchange Commission. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Enanta undertakes no obligation to update or revise these statements, except as may be required by law. Tables to Follow View source version on businesswire.com: https://www.businesswire.com/news/home/20250811000956/en/ Contacts Media and Investors Contact: Jennifer Viera [email protected]