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What changed in ENANTA PHARMACEUTICALS INC's 10-K — 2024 vs 2025

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Paragraph-level year-over-year comparison of ENANTA PHARMACEUTICALS INC's 2024 and 2025 10-K annual filings, covering the Business, Risk Factors, Legal Proceedings, Cybersecurity, MD&A and Market Risk sections. Every new, removed and edited paragraph is highlighted side-by-side so you can see exactly what management changed in the 2025 report.

+341 added−323 removedSource: 10-K (2025-11-19) vs 10-K (2024-11-27)

Top changes in ENANTA PHARMACEUTICALS INC's 2025 10-K

341 paragraphs added · 323 removed · 261 edited across 6 sections

Item 1. Business

Business — how the company describes what it does

141 edited+63 added−30 removed224 unchanged
Biggest changeEDP-323, which also has a Fast Track designation from the FDA, is an inhibitor of the RSV L-protein for both major subgroups of RSV that has recently completed a Phase 2 challenge study. • Zelicapavir - N-protein Inhibitor Candidate: We have studied zelicapavir in two Phase 2 studies that were designed to be proof-of-concept and exploratory studies in otherwise healthy young adults (not at high-risk for serious outcomes with RSV) to understand the viral response in the context of RSV infection.
Biggest changeZelicapavir has been studied in two Phase 2 studies, each in a different high-risk patient population. EDP-323, which also has a Fast Track designation from the FDA, is an inhibitor of the RSV L-protein for both major subgroups of RSV that has completed a Phase 2 challenge study.
Replication inhibitors (e.g., N and L inhibitors) work by blocking viral replication at its source, stopping the production on new virions. They have demonstrated a higher bar to the emergence of viral resistance.
Replication inhibitors (e.g., N and L inhibitors) work by blocking viral replication at its source, stopping production on new virions. They have demonstrated a higher bar to the emergence of viral resistance.
Thus, there is a significant need for an efficacious and safe oral agent. 13 Scientific Background Dysregulation of the Th2 immune response drives many allergic and autoimmune diseases, including AD and asthma, which is characterized by an overproduction of IL-4 and IL-13.
Thus, there is a significant need for an efficacious and safe oral agent. Scientific Background Dysregulation of the Th2 immune response drives many allergic and autoimmune diseases, including AD and asthma, which is characterized by an overproduction of IL-4 and IL-13.
Furthermore, clinical validation of this pathway exists in a number of immunology indications from anti-IL-4/13 monoclonal antibodies and JAK inhibitors, which block the IL-4/13 signaling pathway.
Furthermore, clinical validation of this pathway exists in a number of immunology indications from anti-IL-4 and 13 monoclonal antibodies and JAK inhibitors, which block the IL-4/IL-13 signaling pathway.
In the case of some products for severe or life-threatening 22 diseases, especially when the product may be too inherently toxic to ethically administer to healthy volunteers, the initial human testing is often conducted only in patients having the specific disease. • Phase 2 .
In the case of some products for severe or life-threatening diseases, 22 especially when the product may be too inherently toxic to ethically administer to healthy volunteers, the initial human testing is often conducted only in patients having the specific disease. • Phase 2 .
The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During the approval process, the FDA also will determine whether a Risk Evaluation and Mitigation Strategy, or REMS, is 23 necessary to assure the safe use of the drug.
The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During the approval process, the FDA also will determine whether a Risk Evaluation and Mitigation Strategy, or REMS, is necessary to assure the safe use 23 of the drug.
The Inflation Reduction Act passed by Congress in 2022 (discussed below), authorized the Centers for Medicare and Medicaid Services, or CMS, to begin negotiating the prices on certain drugs based on factors such as research & developments costs and the health economic impact of a particular therapy.
The Inflation Reduction Act passed by Congress in 2022 (discussed below), authorized the Centers for Medicare & Medicaid Services, or CMS, to begin negotiating the prices on certain drugs based on factors such as research & developments costs and the health economic impact of a particular therapy.
The approvals of MAVYRET/MAVIRET are supported by data from nine registrational studies in AbbVie’s clinical development program, which evaluated more than 2,300 patients in 27 countries across all major HCV genotypes (GT1-6) and special populations: • 8 weeks for treatment-naïve, non-cirrhotic patients: In November 2016, results from several Phase 3 studies of this combination demonstrated 97.5% of chronic HCV infected patients without cirrhosis and new to treatment across all major genotypes (GT1-6) achieved sustained virologic response at 12 weeks post-treatment, referred to as SVR 12 , with just 8 weeks of MAVYRET/MAVIRET treatment. • 8 weeks for GT-3: Data from AbbVie’s ENDURANCE-3 study were presented at the 2017 ILC, demonstrating that 95% of patients with challenging-to-treat, genotype 3, or GT3, chronic HCV infection, without cirrhosis and new to treatment, achieved SVR 12 after 8 weeks of treatment with MAVYRET/MAVIRET. • 8 weeks for compensated cirrhosis: Based on data from AbbVie’s EXPEDITION-8 study, which demonstrated that with 8 weeks of MAVYRET treatment, 100 percent (n=273/273) of genotype 1, 2, 4, 5 and 6 patients achieved a sustained virologic response 8 weeks after treatment (SVR 8 ) per protocol analysis.
The approvals of MAVYRET/MAVIRET for the treatment of CKD are supported by data from nine registrational studies in AbbVie’s clinical development program, which evaluated more than 2,300 patients in 27 countries across all major HCV genotypes (GT1-6) and special populations: • 8 weeks for treatment-naïve, non-cirrhotic patients: In November 2016, results from several Phase 3 studies of this combination demonstrated 97.5% of chronic HCV infected patients without cirrhosis and new to treatment across all major genotypes (GT1-6) achieved sustained virologic response at 12 weeks post-treatment, referred to as SVR 12 , with just 8 weeks of MAVYRET/MAVIRET treatment. • 8 weeks for GT-3: Data from AbbVie’s ENDURANCE-3 study were presented at the 2017 ILC, demonstrating that 95% of patients with challenging-to-treat, genotype 3, or GT3, chronic HCV infection, without cirrhosis and new to treatment, achieved SVR 12 after 8 weeks of treatment with MAVYRET/MAVIRET. • 8 weeks for compensated cirrhosis: Based on data from AbbVie’s EXPEDITION-8 study, which demonstrated that with 8 weeks of MAVYRET treatment, 100 percent (n=273/273) of genotype 1, 2, 4, 5 and 6 patients achieved a sustained virologic response 8 weeks after treatment (SVR 8 ) per protocol analysis.
These fraud and abuse laws include: • The federal Anti-Kickback Law, which prohibits, among other things, knowingly or willingly offering, paying, soliciting or receiving remuneration, directly or indirectly, in cash or in kind, to induce or reward the purchasing, leasing, ordering or arranging for or recommending the purchase, lease or order of any health care items or service for which payment may be made, in whole or in part, by federal health care programs such as Medicare and Medicaid; • The federal civil False Claims Act, which prohibits, among other things, individuals or entities from knowingly presenting, or causing to be presented, a false or fraudulent claim for payment of government funds or knowingly making, using or causing to be made or used, a false record or statement material to an obligation to pay money to the government or knowingly concealing or knowingly and improperly avoiding, decreasing or concealing an obligation to pay money to the federal government; • The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which imposes criminal liability for knowingly and willfully executing a scheme to defraud any healthcare benefit program, knowingly and willfully embezzling or stealing from a health care benefit program, willfully obstructing a criminal investigation of a health care offense, or knowingly and willfully making false statements relating to healthcare matters; • The federal Physician Payment Sunshine Act, being implemented as the Open Payments Program, requires certain pharmaceutical manufacturers to engage in extensive tracking of payments and other transfers of value to physicians and teaching hospitals, and to submit such data to the Centers for Medicare and Medicaid Studies, or CMS, which will then make all of this data publicly available on the CMS website; and 26 • Analogous state laws and regulations, including state anti-kickback and false claims laws, which may apply to items or services reimbursed under Medicaid and other state programs or, in several states, apply regardless of the payer, as well as other state laws that require pharmaceutical companies to report expenses related to the marketing and promotion of pharmaceutical products, prohibit certain gifts or payments to health care providers in the state, and/or require pharmaceutical companies to implement compliance programs or marketing codes of conduct.
These fraud and abuse laws include: • The federal Anti-Kickback Statute, which prohibits, among other things, knowingly or willingly offering, paying, soliciting or receiving remuneration, directly or indirectly, in cash or in kind, to induce or reward the purchasing, leasing, ordering or arranging for or recommending the purchase, lease or order of any health care items or service for which payment may be made, in whole or in part, by federal health care programs such as Medicare and Medicaid; • The federal civil False Claims Act, which prohibits, among other things, individuals or entities from knowingly presenting, or causing to be presented, a false or fraudulent claim for payment of government funds or knowingly making, using or causing to be made or used, a false record or statement material to an obligation to pay money to the government or knowingly concealing or knowingly and improperly avoiding, decreasing or concealing an obligation to pay money to the federal government; • The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which imposes criminal liability for knowingly and willfully executing a scheme to defraud any healthcare benefit program, knowingly and willfully embezzling or stealing from a health care benefit program, willfully obstructing a criminal 26 investigation of a health care offense, or knowingly and willfully making false statements relating to healthcare matters; • The federal Physician Payment Sunshine Act, being implemented as the Open Payments Program, requires certain pharmaceutical manufacturers to engage in extensive tracking of payments and other transfers of value to physicians and teaching hospitals, and to submit such data to the Centers for Medicare & Medicaid Studies, or CMS, which will then make all of this data publicly available on the CMS website; and • Analogous state laws and regulations, including state anti-kickback and false claims laws, which may apply to items or services reimbursed under Medicaid and other state programs or, in several states, apply regardless of the payer, as well as other state laws that require pharmaceutical companies to report expenses related to the marketing and promotion of pharmaceutical products, prohibit certain gifts or payments to health care providers in the state, and/or require pharmaceutical companies to implement compliance programs or marketing codes of conduct.
Additionally, the Affordable Care Act: • increased the minimum level of Medicaid rebates payable by manufacturers of brand-name drugs from 15.1% to 23.1%; • required collection of rebates for drugs paid by Medicaid managed care organizations; • required manufacturers to participate in a coverage gap discount program, under which they must agree to offer 50% point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their 28 coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D, beginning January 2011; and • imposed a non-deductible annual fee on pharmaceutical manufacturers or importers who sell “branded prescription drugs” to specified federal government programs.
Additionally, the Affordable Care Act: • increased the minimum level of Medicaid rebates payable by manufacturers of brand-name drugs from 15.1% to 23.1%; • required collection of rebates for drugs paid by Medicaid managed care organizations; • required manufacturers to participate in a coverage gap discount program, under which they must agree to offer 50% point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D, beginning January 2011; and • imposed a non-deductible annual fee on pharmaceutical manufacturers or importers who sell “branded prescription drugs” to specified federal government programs.
If we terminate the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted us (i) a non-exclusive, perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate and (ii) an exclusive (even as to AbbVie), perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in joint intellectual property rights to develop product candidates resulting from covered compounds and to commercialize any products derived from such compounds.
If we terminate the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted us (i) a non-exclusive, perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate and (ii) an exclusive (even as to AbbVie), perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in joint intellectual property rights to develop product candidates resulting from covered compounds and to 16 commercialize any products derived from such compounds.
There are two major subgroups of RSV, designated RSV-A and RSV-B, each of which contains numerous genotypes. Both groups are viewed as capable of causing RSV infections that can result in hospitalization. The RSV genome consists of ten genes that encode for 11 proteins, namely NS1, NS2, N, P, M, 7 SH, G, F, M2-1, M2-2, and L.
There are two major subgroups of RSV, designated RSV-A and RSV-B, each of which contains numerous genotypes. Both groups are viewed as capable of causing RSV infections that can result in hospitalization. The RSV genome consists of ten genes that encode for 11 proteins, namely NS1, NS2, N, P, M, SH, G, F, M2-1, M2-2, and L.
AbbVie’s MAVYRET/MAVIRET regimen currently faces competition in various world markets and subpopulations of HCV from Gilead’s Epclusa ® (a fixed dose combination of sofosbuvir and velpatasvir), Vosevi ® (a triple combination therapy of sofosbuvir, velpatasvir and voxilaprevir approved by the FDA for specified sofosbuvir -treatment failures and NS5A-inhibitor treatment failures) and Harvoni ® (a fixed-dose combination of sofosbuvir and ledipasvir); and to a lesser extent - Merck’s Zepatier ® (a fixed-dose combination of grazoprevir and elbasvir).
AbbVie’s MAVYRET/MAVIRET regimen currently faces competition in various world markets and subpopulations of HCV from Gilead’s Epclusa ® (a fixed dose combination of sofosbuvir and velpatasvir), Vosevi ® (a triple combination therapy of sofosbuvir, velpatasvir and voxilaprevir approved by the FDA for specified sofosbuvir -treatment 19 failures and NS5A-inhibitor treatment failures) and Harvoni ® (a fixed-dose combination of sofosbuvir and ledipasvir); and to a lesser extent - Merck’s Zepatier ® (a fixed-dose combination of grazoprevir and elbasvir).
We continue to invest substantial resources in research programs to discover compounds targeting new disease areas. 5 Our Out-Licensed Products HCV . Two protease inhibitors developed through our Collaborative Development and License Agreement with AbbVie have been clinically tested, manufactured, and commercialized by AbbVie as part of its combination regimens for HCV.
We continue to invest substantial resources in research programs to discover compounds targeting new disease areas. Our Out-Licensed Products HCV . Two protease inhibitors developed through our Collaborative Development and License Agreement with AbbVie have been clinically tested, manufactured, and commercialized by AbbVie as part of its combination regimens for HCV.
Our decisions regarding our proprietary programs will be based on the results of our clinical studies and the potential for collaborations, including combinations with one or more drugs targeting other mechanisms of action in these diseases. • Continue to use our existing resources and future cash flow from our AbbVie collaboration to fund our research and development activities .
Our decisions regarding our proprietary programs will be based on the results of our studies and the potential for collaborations, including combinations with one or more drugs targeting other mechanisms of action in these diseases. • Continue to use our existing resources and future cash flow from our AbbVie collaboration to fund our research and development activities .
Current therapies modulate only a small subset of either mast cell stimulants or the downstream mediators of inflammation that mast cells produce (e.g., antihistamines), but do not address the underlying cause of disease, as they do not directly affect mast cells themselves. We are targeting mast cells by inhibiting KIT, a central regulator of mast cell development and activation.
Current therapies modulate only a small subset of either mast cell stimulants or the downstream mediators of inflammation that mast cells produce (e.g., antihistamines), but do not address the underlying cause of disease, as they do not directly affect mast cells themselves. 12 We are targeting mast cells by inhibiting KIT, a central regulator of mast cell development and activation.
Gilead launched authorized generic versions of Epclusa and Harvoni through its subsidiary, Asegua Therapeutics, LLC, which have had an impact on 19 the competitive landscape. For example, the state of Louisiana selected Asegua as their HCV subscription model pharmaceutical partner to provide the state with unrestricted access to its direct-acting antiviral medication.
Gilead launched authorized generic versions of Epclusa and Harvoni through its subsidiary, Asegua Therapeutics, LLC, which have had an impact on the competitive landscape. For example, the state of Louisiana selected Asegua as their HCV subscription model pharmaceutical partner to provide the state with unrestricted access to its direct-acting antiviral medication.
To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost-effectiveness of a particular product candidate to currently available therapies. Other member states allow companies to fix their own 29 prices for medicines but monitor and control company profits.
To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost-effectiveness of a particular product candidate to currently available therapies. Other member states allow companies to fix their own prices for medicines but monitor and control company profits.
AbbVie granted us a co-exclusive (together with AbbVie), royalty-free, fully paid license, without the right to grant sublicenses, to certain of AbbVie’s intellectual property, AbbVie’s interest in joint intellectual property and improvements discovered by AbbVie, for the purpose of allowing us to conduct certain 15 development and commercialization activities in the United States relating to protease inhibitors.
AbbVie granted us a co-exclusive (together with AbbVie), royalty-free, fully paid license, without the right to grant sublicenses, to certain of AbbVie’s intellectual property, AbbVie’s interest in joint intellectual property and improvements discovered by AbbVie, for the purpose of allowing us to conduct certain development and commercialization activities in the United States relating to protease inhibitors.
The proposed legislation would replace the rebate model with a model that relies on up-front discounts and would potentially significantly alter the relationship between manufacturers and PBMs. As noted above, state legislatures are also increasingly considering and adopting laws that exert greater influence over the price of prescription drugs.
The proposed legislation would replace the rebate model with a model that relies on up-front discounts and would potentially significantly alter the relationship between manufacturers and PBMs. 29 As noted above, state legislatures are also increasingly considering and adopting laws that exert greater influence over the price of prescription drugs.
The joint steering committee is comprised of three of our senior personnel and three senior personnel from AbbVie; however, AbbVie has final authority to make all decisions regarding development and commercialization activities. The research program and the evaluation period, which was performed by both parties, ended in June 2011.
The joint steering committee is comprised of three of our senior personnel and 15 three senior personnel from AbbVie; however, AbbVie has final authority to make all decisions regarding development and commercialization activities. The research program and the evaluation period, which was performed by both parties, ended in June 2011.
Only one patent applicable to an approved drug is eligible for the extension and the application for the extension must be submitted within 60 days of approval, prior to the expiration of the patent. The United States Patent and Trademark Office, in consultation with the FDA, reviews and approves the application 25 for any patent term extension or restoration.
Only one patent applicable to an approved drug is eligible for the extension and the application for the extension must be submitted within 60 days of approval, prior to the expiration of the patent. The United States Patent and Trademark Office, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration.
Based on the growing safety profile of zelicapavir and differences in the range of the course of RSV infection in higher risk populations, which have always been our target populations, we have continued 8 the development of zelicapavir in patients at high-risk for developing severe infection leading to hospitalization or death.
Based on the growing safety profile of zelicapavir and differences in the range of the course of RSV infection in higher risk populations, which have always been our target populations, we continued the development of zelicapavir in patients at high-risk for developing severe infection leading to hospitalization or death.
Accordingly, the final expiration date of the agreement is currently indeterminable. 16 Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice.
Accordingly, the final expiration date of the agreement is currently indeterminable. Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice.
HCV sales have declined since their peak in 2015 due to 14 payers obtaining additional discounts, competitive market dynamics and a decline in the number of patients treated annually after the initial wave of diagnosed chronic HCV patients who had urgency for treatment.
HCV sales have declined since their peak in 2015 due to payers obtaining additional discounts, competitive market dynamics and a decline in the number of patients treated annually after the initial wave of diagnosed chronic HCV patients who had urgency for treatment.
Two Phase 1b studies of EDP-514 demonstrate the 18 compound is safe with strong antiviral activity in two different chronic HBV patient populations – those who have a high viral load and those who are on a treatment with a nucleoside reverse transcriptase inhibitor.
Two Phase 1b studies of EDP-514 demonstrate the compound is safe with strong antiviral activity in two different chronic HBV patient populations – those who have a high viral load and those who are on a treatment with a nucleoside reverse transcriptase inhibitor.
As a condition of approval, the FDA generally requires that a sponsor of the product perform adequate and well-controlled post-marketing clinical studies to establish safety and efficacy for the approved indication. Failure to conduct such studies or failure of the studies to establish required safety and efficacy may result in revocation of approval.
As a condition of approval, the FDA generally requires that a sponsor of the product perform adequate and well-controlled post-marketing clinical studies to establish safety and efficacy for the approved indication. Failure to conduct such studies or failure of the studies to establish required safety 24 and efficacy may result in revocation of approval.
The Hatch-Waxman Amendments permit a patent restoration term of up to five years as compensation for patent term lost during federal regulatory review preceding the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date.
The Hatch-Waxman Amendments 25 permit a patent restoration term of up to five years as compensation for patent term lost during federal regulatory review preceding the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date.
Since its adoption, the ACA contains a number of provisions, including those governing enrollment in federal healthcare programs, reimbursement changes and fraud and abuse, which have affected existing government healthcare programs and have resulted in the development of new programs, including Medicare payment tied to performance.
Since its adoption, the ACA contains a number of provisions, including those governing enrollment in federal healthcare programs, reimbursement changes and fraud and abuse, which have affected existing government healthcare programs and 28 have resulted in the development of new programs, including Medicare payment tied to performance.
However, only a few of the issued patents 20 and/or pending patent applications cover the lead product candidates in a given program. We also have patent applications pending for earlier stage immunology programs. RSV, SARS-CoV-2, HBV.
However, only a few of the issued patents and/or pending patent applications cover the lead product candidates in a given program. We also have patent applications pending for earlier stage immunology programs. RSV, SARS-CoV-2, HBV.
Competitive Landscape Several companies are seeking to develop antiviral treatments for RSV infection in adult and pediatric patients. Ark Biosciences and Shionogi have compounds in clinical development. There are several prophylaxis options on the market or in development.
Competitive Landscape Several companies are seeking to develop antiviral treatments for RSV infection in adult and pediatric patients. Ark Biosciences and Shionogi have compounds in clinical development. 7 There are several prophylaxis options on the market or in development.
This co-formulated combination, marketed under the tradenames MAVYRET ® (U.S.) and MAVIRET ® (ex-U.S.), contains two novel DAAs that target and inhibit proteins essential for the replication of HCV.
This co-formulated combination, marketed 14 under the tradenames MAVYRET ® (U.S.) and MAVIRET ® (ex-U.S.), contains two novel DAAs that target and inhibit proteins essential for the replication of HCV.
The FDA also requires, as a condition for 24 accelerated approval, pre-approval of promotional materials, which could adversely impact the timing of the commercial launch or subsequent marketing of the product.
The FDA also requires, as a condition for accelerated approval, pre-approval of promotional materials, which could adversely impact the timing of the commercial launch or subsequent marketing of the product.
Certain countries outside of the United States have a similar process that requires the submission of a clinical trial application much like the IND prior to the commencement of human clinical trials.
Certain 27 countries outside of the United States have a similar process that requires the submission of a clinical trial application much like the IND prior to the commencement of human clinical trials.
In addition, we engage from time to time in discussions with third parties to out-license intellectual property that no longer fits in our strategic priorities for our internal research and development programs. For example, in December 2022 we out-licensed one of our antibiotic compounds in exchange for a $1.0 million up-front fee and future milestone payments and royalties.
In addition, we engage in discussions with third parties to out-license intellectual property that no longer fits in our strategic priorities for our internal research and development programs. For example, in December 2022 we out-licensed one of our antibiotic compounds in exchange for a $1.0 million up-front fee and future milestone payments and royalties.
STAT-6 is a transcription factor predominantly expressed in immune and epithelial cells that is responsible for IL-4/IL-13 signaling, which results in a Th2 dominant phenotype. Evidence for STAT6 as a key driver of AD and asthma is the presence of STAT6 gain-of-function variants resulting in severe AD and STAT6 loss-of-function variants protect against type 2 high asthma.
STAT6 is a transcription factor predominantly expressed in immune and epithelial cells that is responsible for IL-4/IL-13 signaling, which results in a Th2 dominant phenotype. Evidence for STAT6 as a key driver of AD and asthma is the presence of STAT6 gain-of-function variants resulting in severe AD and STAT6 loss-of-function variants protect against type 2 high asthma.
In addition, we may seek to augment our product candidate pipeline through the acquisition or in-licensing of external assets and/or technologies in one or more of our disease areas of focus. • Collaborate or out-license, where and when appropriate, with pharmaceutical partners to accelerate the development and commercialization of our proprietary compounds and/or create combination therapies .
We may also seek to augment our product candidate pipeline through the acquisition or in-licensing of external assets and/or technologies in one or more of our disease areas of focus. • Collaborate or out-license, where and when appropriate, with pharmaceutical partners to accelerate the development and commercialization of our proprietary compounds and/or create combination therapies .
MAVYRET/MAVIRET is approved in the U.S., EU, Japan and numerous other countries globally as an 8-week, pan-genotypic, fixed-dose combination treatment, dosed once-daily as three oral tablets, taken with food, for chronic HCV patients without cirrhosis and new to treatment.
MAVYRET/MAVIRET is approved in the U.S., EU, Japan and numerous other countries globally as an 8-week, pan-genotypic, fixed-dose combination treatment, dosed once-daily as three oral tablets, taken with food, for acute or chronic HCV patients without cirrhosis and new to treatment.
Vir, GSK, Arbutus, and Roche have multiple combination regimens under investigation in later stage clinical studies. In addition, a number of companies have Phase 1 or earlier stage HBV programs. For CSU, there are a number of different mechanisms being explored, including inhibitors of IL-4R, IgE, BTK, SIGLEC-6, and MRGPRX2.
Vir, GSK, Arbutus, and Roche have multiple combination regimens under investigation in later stage clinical studies. In addition, a number of companies have Phase 1 or earlier stage HBV programs. For CSU, there are a number of different mechanisms being explored, including inhibitors of IL-4R, IgE, BTK, and MRGPRX2.
While most companies are developing potential approaches geared toward the F-protein (or fusion protein, responsible for mediating viral entry of RSV into host cells), we are focused on mechanisms, such as the N-protein and L-protein inhibitors, that target the replication process of RSV directly.
While certain companies are developing potential approaches geared toward the F-protein (or fusion protein, responsible for mediating viral entry of RSV into host cells), we are focused on mechanisms, such as the N-protein and L-protein inhibitors, that target the replication process of RSV directly.
We have a discovery stage program to develop oral inhibitors of the signal transducer and activator of transcription 6 transcription factor, known as STAT6, for the treatment of type 2 immune driven diseases, initially focusing on AD and potentially other indications by blocking the IL-4/IL-13 signaling pathway, thereby addressing a primary driver of these diseases.
We have a preclinical stage program to develop oral inhibitors of the signal transducer and activator of transcription 6 transcription factor, known as STAT6, for the treatment of type 2 immune driven diseases. We are initially focusing on AD and potentially other indications by blocking the IL-4/IL-13 signaling pathway, thereby addressing a primary driver of these diseases.
Several companies are seeking to develop antiviral treatments for RSV infection in adult and pediatric patients. Ark Biosciences, Gilead and Shionogi all have compounds in clinical development. There are several prophylaxis options on the market or in development.
Several companies are seeking to develop antiviral treatments for RSV infection in adult and pediatric patients. Ark Biosciences and Shionogi have compounds in clinical development. There are several prophylaxis options on the market or in development.
Mean trough plasma concentrations were maintained at 16-fold above the protein-adjusted EC90 with the low dose, and 35-fold above the protein-adjusted EC90 with the high dose, for both RSV A and B strains. In addition, EDP-323 demonstrated a favorable safety profile over a 5-day dosing period and through 28 days of follow-up.
Mean trough plasma concentrations were maintained at 16-fold above the protein-adjusted EC 90 with the low dose, and 35-fold above the protein-adjusted EC 90 with the high dose, for both RSV-A and RSV-B strains. In addition, EDP-323 demonstrated a favorable safety profile over a 5-day dosing period and through 28 days of follow-up.
Virology 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.
Virology: We discovered glecaprevir, the second of two antiviral protease inhibitors developed through our collaboration with AbbVie for the treatment of acute or chronic infection with hepatitis C virus, or HCV.
We currently plan to focus our immunology drug development efforts on the following disease indications: • 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 • Atopic dermatitis, or AD, a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin with significant quality of life impacts such as leading a limited lifestyle, avoidance of social 3 interactions and a reduced range of activities, with AD affecting 7.3% of the US adult population, of whom ~40% have moderate to severe disease.
We currently plan to focus our initial immunology drug development proof-of-concept efforts on the following disease indications: • 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 • Atopic dermatitis, or AD, a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin with significant quality of life impacts such as leading a limited lifestyle, avoidance of social interactions and a reduced range of activities, with AD affecting 7.3% of the US adult population, of whom approximately 40% have moderate to severe disease.
As of October 2023, the World Health Organization estimated nearly 7 million deaths have been caused by COVID-19. There are also many patients who experience continuing effects of COVID-19, often referred to as “long COVID”. While vaccines that reduce the severity of COVID-19 are available, uptake has not been optimal.
As of October 2025, the World Health Organization estimated over 7 million deaths have been caused by COVID-19. There are also many patients who experience continuing effects of COVID-19, often referred to as “long COVID”. While vaccines that reduce the severity of COVID-19 are available, uptake has not been optimal.
Under this collaboration, we have received royalty payments from AbbVie totaling $924 million through September 30, 2024. Further details of these tiered royalties are set forth in Note 7 in Notes to Consolidated Financial Statements included in this report, which are incorporated herein by this reference.
Under this collaboration, we have received royalty payments from AbbVie totaling $954 million through September 30, 2025. Further details of these tiered royalties are set forth in Note 7 in Notes to Consolidated Financial Statements included in this report, which are incorporated herein by this reference.
In addition, the SEC maintains an Internet website that contains reports, proxy and information statements, and other information regarding Enanta Pharmaceuticals, Inc. and other issuers that file electronically with the SEC. The SEC’s Internet website address is http://www.sec.gov. 31
In addition, the SEC maintains a website that contains reports, proxy and information statements, and other information regarding Enanta Pharmaceuticals, Inc. and other issuers that file electronically with the SEC. The SEC’s website address is http://www.sec.gov. 31
For AD, the moderate-severe AD treatment landscape is dominated by biologics targeting the IL-4 and/or IL-13 pathway (e.g., DUPIXENT ® (dupilumab) and ADBRY ® (tralokinumab-ldrm)), with JAK inhibitors (e.g., RINVOQ ® (upadacitinib) and CIBINQO ® (abrocitinib)) as the only oral option. Multiple oral mechanisms are in development, including inhibitors of MRGPRX2, IRAK4, STAT6, RASP and PKM2.
For AD, the moderate-severe AD treatment landscape is dominated by biologics targeting the IL-4 and/or IL-13 pathway (e.g., DUPIXENT ® (dupilumab), ADBRY ® (tralokinumab-ldrm), and EBGLYSS (lebrikizumab-lbkz)), with JAK inhibitors (e.g., RINVOQ ® (upadacitinib) and CIBINQO ® (abrocitinib)) as the only oral option. Multiple oral mechanisms are in development, including modulators of MRGPRX2, IRAK4, ITK, STAT6, RASP and PKM2.
Mechanisms under study for HBV include entry inhibitors, core inhibitors or capsid assembly modulators (CAMs), siRNA/ASO targeting the HBV S antigen, and immune modulators (eg; TLRs, PD-L1s, therapeutic vaccines, etc).
Mechanisms under study for HBV include entry inhibitors, core inhibitors or capsid assembly modulators (CAMs), siRNA/ASO targeting the HBV S antigen, and immune modulators (e.g., TLRs, PD-L1s, therapeutic vaccines, etc.).
We may choose to collaborate with other companies to accelerate the global clinical development of one or more of our product candidates. We are also prepared to join forces, where and when appropriate, with collaborators with compounds targeting other mechanisms of action in diseases where there is the potential for better treatments with combination therapies, as we did in HCV.
We may choose to collaborate with other companies to accelerate the global clinical development of one or more of our product candidates. We are also prepared to join forces, where and when appropriate, with collaborators where there is the potential for better treatments with combination therapies, as we did in HCV.
The majority (>90%) of moderate to severe patients are treated with an IL-4/IL-13 monoclonal antibody (e.g., DUPIXENT® (dupilumab)) despite modest efficacy, while a minority ( ® (upadacitinib)) due to safety concerns (black box warning for serious infections, mortality, malignancy, MACE, and thrombosis).
The majority (>90%) of moderate to severe patients are treated with an IL-4 and IL-13 monoclonal antibody (e.g., DUPIXENT® (dupilumab)) despite modest efficacy, while a minority ( ® (upadacitinib)) due to safety concerns (black box warning for serious infections, mortality, malignancy, major adverse cardiovascular events, or MACE, and thrombosis).
Competitive Landscape The moderate-severe AD treatment landscape is dominated by biologics targeting the IL-4 and/or IL-13 pathway (e.g., DUPIXENT ® (dupilumab) and ADBRY ® (tralokinumab-ldrm)), with JAK inhibitors (e.g., RINVOQ ® (upadacitinib) and CIBINQO ® (abrocitinib)) as the only oral option. Multiple oral mechanisms are in development, including inhibitors of MRGPRX2, IRAK4, STAT6, RASP and PKM2.
Competitive Landscape The moderate-to-severe AD treatment landscape is dominated by biologics targeting the IL-4 and/or IL-13 pathway (e.g., DUPIXENT ® (dupilumab), ADBRY ® (tralokinumab-ldrm), and EBGLYSS™ (lebrikizumab-lbkz)), with JAK inhibitors (e.g., RINVOQ ® (upadacitinib) and CIBINQO ® (abrocitinib)) as the only oral option. Multiple oral mechanisms are in development, including modulators of MRGPRX2, IRAK4, ITK, STAT6, RASP and PKM2.
Research and Development Our research and development expenses were $131.5 million, $163.5 million and $164.5 million for the fiscal years ended September 30, 2024, 2023, and 2022, respectively. Manufacturing We do not have our own manufacturing capabilities, except with respect to limited amounts of active pharmaceutical ingredients needed for preclinical development.
Research and Development Our research and development expenses were $106.7 million, $131.5 million and $163.5 million for the fiscal years ended September 30, 2025, 2024, and 2023, respectively. Manufacturing We do not have our own manufacturing capabilities, except with respect to limited amounts of active pharmaceutical ingredients needed for preclinical development.
AstraZeneca/Sanofi (BEYFORTUS ® ) and Merck (clesrovimab – Phase 3 complete) are developing long-acting monoclonal antibodies for prophylaxis use in infants, and Pfizer has an approved maternal vaccine (ABRYSVO ® ), all of which provide passive immunity to infants. Sanofi is also evaluating a vaccine in infants and toddlers (RSVt vaccine – Phase 3).
Long-acting monoclonal antibodies from AstraZeneca/Sanofi (BEYFORTUS ® ) and Merck (ENFLONSIA™) are approved for prophylaxis use in infants, and Pfizer has an approved maternal vaccine (ABRYSVO ® ), all of which provide passive immunity to infants. Sanofi is also evaluating a vaccine in infants and toddlers (RSVt vaccine – Phase 3).
Since the introduction of Gilead’s Harvoni ® and AbbVie’s VIEKIRA PAK ® in late 2014, the reported worldwide sales of the leading HCV therapies have declined from $23 billion in 2015 to $3.2 billion in 2023. Through the first nine months of calendar 2024, reported worldwide net sales were $2.3 billion.
Since the introduction of Gilead’s Harvoni ® and AbbVie’s VIEKIRA PAK ® in late 2014, the reported worldwide sales of the leading HCV therapies have declined from $23 billion in 2015 to $2.9 billion in 2024. Through the first nine months of calendar 2025, reported worldwide net sales were $2.0 billion.
The disease affects an estimated 7.3% of the US adult population and approximately 40% of those have moderate to severe disease.
The disease affects an estimated 7.3% of the U.S, adult population and approximately 40% of those have moderate to severe disease.
EDP-323 is not expected to have cross-resistance to other classes of inhibitors and has the potential to be used alone, or in combination with other RSV mechanisms, to broaden the treatment window or addressable patient populations. In September 4 2024, we announced positive topline results for EDP-323 in a Phase 2a challenge study of healthy adults infected with RSV.
EDP-323 is not expected to have cross-resistance to other classes of inhibitors and has the potential to be used alone, or in combination with other RSV mechanisms, to broaden the treatment window or addressable patient populations. Phase 2a Study of EDP-323 In September 2024, we announced positive top-line results for EDP-323 in a Phase 2a human challenge study.
Many companies are seeking to develop new HBV drugs that alone or in combination with other mechanisms could lead to a functional cure for HBV. Vir, GSK, Arbutus, and Roche have multiple combination regimens under investigation in later stage clinical studies. In addition, a number of companies have Phase 1 or earlier stage HBV programs.
Many companies are seeking to develop new HBV drugs that alone or in combination with other mechanisms could lead to a functional cure for HBV. Vir, GSK, Arbutus, and Roche have multiple combination regimens under investigation in later stage clinical studies.
In the pediatric population, both the maternal vaccine and the prophylactic antibody approaches provide only passive immunity, which only lasts for a limited period of time and will just shift the time of first RSV infection to the next season.
In the pediatric population, both the maternal vaccine and the prophylactic antibody approaches provide only passive immunity, which lasts for a limited period of time (approximately 4-5 months) and will generally shift the time of first RSV infection to the next season.
ITEM 1. B USINESS BUSINESS Overview 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.
ITEM 1. B USINESS BUSINESS Overview We are a biotechnology company that uses our robust, chemistry-driven approach and drug discovery capabilities to discover and develop small molecule drugs for virology and immunology indications.
Specifically for KIT inhibitors, there are companies with antibodies in development, including Celldex (barzolvolimab - Phase 3) and Jasper (briquilimab - Phase 1b/2a), as well as companies with oral, small molecules in early clinical development (Third Harmonic and Blueprint) or preclinical development (Arcus and Alivexis).
Specifically for KIT inhibitors, there are companies with antibodies in development, including Celldex (barzolvolimab - Phase 3) and Jasper (briquilimab - Phase 1b/2a), as well as companies with oral, small molecules in early clinical development (Sanofi/Blueprint).
Each of our major research and development programs for RSV as well as our out-licensed products for HCV and our SARS-CoV-2 and HBV assets, typically has several pending patent claims and issued patents in the program area containing claims to compounds, methods of use and processes for synthesis.
Our ability to be competitive will depend on the success of this strategy. 20 Each of our major research and development programs for RSV as well as our out-licensed products for HCV and our SARS-CoV-2 and HBV assets, typically has several pending patent claims and issued patents in the program area containing claims to compounds, methods of use and processes for synthesis.
EDP-323 is not expected to have cross-resistance to other classes of inhibitors and has the potential to be used alone, or in combination with other RSV mechanisms, to broaden the treatment window or addressable patient populations. We completed a Phase 1 clinical study of EDP-323 in June 2023.
EDP-323 is not expected to have cross-resistance to other classes of inhibitors and has the potential to be used alone, or in combination with other RSV mechanisms, to broaden the treatment window or addressable patient populations. o Phase 2a Study of EDP-323 .
FDA and other governmental sanctions could include refusal to approve pending applications, withdrawal of an approval, a clinical hold, enforcement letters, product recalls, product seizures, total 21 or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement or civil or criminal penalties.
FDA and other governmental sanctions could include refusal to approve pending applications, withdrawal of an approval, a clinical hold, enforcement letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement or civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us.
The intent-to-treat-infected population (ITT-I) was defined as all randomized participants receiving challenge virus and at least one dose of study drug with confirmed RSV infection. EDP-323 demonstrated a rapid and sustained antiviral effect.
The intent-to-treat-infected population (ITT-I) was defined as all randomized participants receiving challenge virus and at least one dose of study drug with confirmed RSV infection.
In addition to nanomolar activity against all SARS-CoV-2 variants tested to date, EDP-235 has potent antiviral activity against other human coronaviruses, enabling the potential for a pan-coronavirus treatment, including possibly coronaviruses that may infect human populations in the future.
We selected EDP-235, an oral inhibitor of the coronavirus 3CL protease, for clinical development. In addition to nanomolar activity against all SARS-CoV-2 variants tested to date, EDP-235 has potent antiviral activity against other human coronaviruses, enabling the potential for a pan-coronavirus treatment, including possibly coronaviruses that may infect human populations in the future.
Specifically for KIT inhibitors, there are companies with antibodies in development, including Celldex (barzolvolimab - Phase 3) and Jasper (briquilimab - Phase 1b/2a), as well as companies with oral, small molecules in early Phase 1 development (Third Harmonic and Blueprint) or preclinical development (Arcus and Alivexis).
Specifically for KIT inhibitors, there are companies with antibodies in development, including Celldex (barzolvolimab - Phase 3) and Jasper (briquilimab - Phase 1b/2a), as well as companies with oral, small molecules in early Phase 1 development (Sanofi).
To date, these treatments have cure rates approaching 100% in several subpopulations. Medical practice defines a “cure” as the point at which there is no quantifiable virus in a patient’s blood for a sustained period of time after cessation of therapy, which is often referred to as a sustained virologic response, or SVR.
Medical practice defines a “cure” as the point at which there is no quantifiable virus in a patient’s blood for a sustained period of time after cessation of therapy, which is often referred to as a sustained virologic response, or SVR.
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.
Glecaprevir is co-formulated as part of AbbVie’s leading brand of direct-acting antiviral, or DAA, combination treatment for HCV, which has been marketed under the tradenames MAVYRET ® (U.S.) and MAVIRET ® (ex-U.S.) (glecaprevir/pibrentasvir) since 2017 for the treatment of chronic HCV. MAVYRET ® was also approved as the first and only treatment for acute HCV infection in June 2025.
Our principal executive offices are located at 4 Kingsbury Avenue, Watertown, Massachusetts 02472, and our telephone number is (617) 607-0800. Our web site address is http:// www.enanta.com . Segment Information We provide segment information in Note 2 to our Consolidated Financial Statements included in Item 8 of this report. We are incorporating that information into this section by this reference.
Our principal executive offices are located at 4 Kingsbury Avenue, Watertown, Massachusetts 02472, and our telephone number is (617) 607-0800. Our website address is http:// www.enanta.com . 30 Segment Information We provide segment information in Notes 2 and 16 to our Consolidated Financial Statements included in Item 8 of this report.
Expedited Development and Review Programs The FDA has four programs intended to expedite the development and review of new drugs addressing unmet medical needs or treating serious or life-threatening conditions: fast track, breakthrough therapy, priority review, and accelerated approval, in addition to emergency use authorization, or EUA, in situations such as the COVID-19 pandemic.
Expedited Development and Review Programs The FDA has four established programs and one pilot program intended to expedite the development and review of new drugs addressing unmet medical needs or treating serious or life-threatening conditions, or drugs that align with U.S. national health priorities: fast track, breakthrough therapy, priority review, and accelerated approval, and the Commissioner’s National Priority Voucher (CNPV) Pilot Program, in addition to emergency use authorization, or EUA, in situations such as the COVID-19 pandemic.
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.
Based on our operating plan, we believe that our existing cash, cash equivalents, and short-term marketable securities as of September 3 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.
Competitive Landscape For COVID, there are two oral antiviral treatments for non-hospitalized, high-risk patients with SARS-CoV-2 infection: PAXLOVID™, a 3CL protease inhibitor (nirmatrelvir) boosted with ritonavir (full approval), and LAGEVRIO™ (molnupiravir), a polymerase inhibitor (Emergency Use Authorization). There are no oral direct acting antivirals for the treatment of SARS-CoV-2 in late-stage global clinical trials.
Competitive Landscape In the United States, there are two oral antiviral treatments for non-hospitalized, high-risk patients with SARS-CoV-2 infection: PAXLOVID™, a 3CL protease inhibitor (nirmatrelvir) boosted with ritonavir (full approval), and LAGEVRIO™ (molnupiravir), a polymerase inhibitor (Emergency Use Authorization).
In all cases, the clinical trials are conducted in accordance with International Conference on 27 Harmonisation (ICH) / WHO Good Clinical Practice standards and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.
The requirements and process governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, the clinical trials are conducted in accordance with International Conference on Harmonisation (ICH) / WHO Good Clinical Practice standards and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.
EDP-514 Our lead clinical candidate for the treatment of chronic infection with HBV is EDP-514, a core inhibitor that displays potent anti-HBV activity in vitro at multiple points in the HBV lifecycle.
In addition, a number of companies have Phase 1 or earlier stage HBV programs. 18 EDP-514 Our lead clinical candidate for the treatment of chronic infection with HBV is EDP-514, a core inhibitor that displays potent anti-HBV activity in vitro at multiple points in the HBV lifecycle.
We also rely on trade secrets, internal know-how, technological innovations and agreements with third parties to develop, maintain and protect our competitive position. Our ability to be competitive will depend on the success of this strategy.
We also rely on trade secrets, internal know-how, technological innovations and agreements with third parties to develop, maintain and protect our competitive position.
As of September 30, 2024, we had $248.2 million in cash, cash equivalents and short-term marketable securities.
As of September 30, 2025, we had $188.9 million in cash, cash equivalents and short-term marketable securities.
We expect to conduct scale-up activities and IND-enabling studies for this program in 2025. Background and Overview of AD AD is a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin, and has significant quality of life impacts such as leading a limited lifestyle, avoidance of social interactions and impacted activities.
Background and Overview of AD AD is a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin, and has significant quality of life impacts such as leading a limited lifestyle, avoidance of social interactions and impacted activities.
For COVID, there are two oral antiviral treatments for non-hospitalized, high-risk patients with SARS-CoV-2 infection: PAXLOVID™, a 3CL protease inhibitor (nirmatrelvir) boosted with ritonavir (full approval), and LAGEVRIO™ (molnupiravir), a polymerase inhibitor (Emergency Use Authorization). There are no oral direct acting antivirals for the treatment of SARS-CoV-2 in late-stage global clinical trials.
In the United States, there are two oral antiviral treatments for non-hospitalized, high-risk patients with SARS-CoV-2 infection: PAXLOVID™, a 3CL protease inhibitor (nirmatrelvir) boosted with ritonavir (full approval), and LAGEVRIO™ (molnupiravir), a polymerase inhibitor (Emergency Use Authorization). The most advanced direct acting oral antiviral for the treatment of high-risk patients with SARS-CoV-2 is in Phase 3 studies (ibuzatrelvir).

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Item 1A. Risk Factors

Risk Factors — what could go wrong, per management

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Biggest changeAbbVie may experience global pricing pressure for its MAVYRET/MAVIRET regimen from such measures, which may be reflected in larger discounts or rebates on its regimens or delayed reimbursement. Also, private and public payors may choose to exclude AbbVie’s MAVYRET/MAVIRET regimen from their formulary coverage lists or limit the types of patients for whom coverage will be provided.
Biggest changeAlso, private and public payors may choose to exclude AbbVie’s MAVYRET/MAVIRET regimen from their formulary coverage lists or limit the types of patients for whom coverage will be provided. Any such change in formulary coverage, discounts or rebates or reimbursement for MAVYRET/MAVIRET would negatively affect the demand for this regimen and our royalty revenue derived from its sales.
Our revenues are dependent upon royalty revenues derived from AbbVie’s net sales of its MAVYRET/MAVIRET regimen for HCV, which includes our protease inhibitor, glecaprevir. If AbbVie is unable to maintain sales of this 32 regimen at or above current levels of sales, our royalty revenues, as well as our retained cash portion of royalties, will be adversely affected.
Our revenues are dependent upon royalty revenues derived from AbbVie’s net sales of its MAVYRET/MAVIRET regimen for HCV, which includes our protease inhibitor, glecaprevir. If AbbVie is unable to maintain sales of this regimen at or 32 above current levels of sales, our royalty revenues, as well as our retained cash portion of royalties, will be adversely affected.
The existence of undesirable side effects resulting from any of our product candidates, or a combination therapy including any of them, could cause us or regulatory authorities, such as the FDA or EMA, to interrupt, 37 delay or halt clinical trials of our product candidates and could result in the FDA or EMA or other regulatory agencies denying further development or approval of our product candidates for any or all targeted indications.
The existence of undesirable side effects resulting from any of our product candidates, or a combination therapy including any of them, could cause us or regulatory authorities, such as the FDA or EMA, to interrupt, delay or halt clinical 37 trials of our product candidates and could result in the FDA or EMA or other regulatory agencies denying further development or approval of our product candidates for any or all targeted indications.
Any failure by our third-party manufacturers to comply with cGMP or failure to scale up manufacturing processes, 43 including any failure to deliver sufficient quantities of product candidates in a timely manner, could lead to a delay in, or failure to obtain, regulatory approval of any of our product candidates.
Any failure by our third-party manufacturers to comply with cGMP or failure to scale up manufacturing processes, including any failure to deliver 43 sufficient quantities of product candidates in a timely manner, could lead to a delay in, or failure to obtain, regulatory approval of any of our product candidates.
In addition, the uncertainties associated with litigation could have a material adverse effect on our ability to raise the funds necessary to conduct our 48 clinical trials, continue our internal research programs, in-license needed technology, or enter into strategic partnerships that would help us bring our product candidates to market.
In addition, the uncertainties associated with litigation could have a material adverse effect on our ability to raise the funds necessary to conduct our clinical trials, 48 continue our internal research programs, in-license needed technology, or enter into strategic partnerships that would help us bring our product candidates to market.
If we, or AbbVie in the case of any licensed HCV product, are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or AbbVie are not able to maintain regulatory compliance, our product candidates or AbbVie’s licensed HCV products may lose any marketing approval that may have been obtained and we may not achieve or sustain profitability, which would adversely affect our business.
If we, or AbbVie in the case of any licensed HCV product, are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or AbbVie are not able to maintain regulatory compliance, our product candidates or AbbVie’s licensed HCV products may lose 39 any marketing approval that may have been obtained and we may not achieve or sustain profitability, which would adversely affect our business.
In addition, manufacturing interruptions or failure to comply with regulatory requirements by any of these manufacturers could significantly delay clinical development of potential products and reduce third-party or clinical researcher interest and support of proposed 44 trials. These interruptions or failures could also impede commercialization of our product candidates and impair our competitive position.
In addition, manufacturing interruptions or failure to comply with regulatory requirements by any of these manufacturers could significantly delay clinical development of potential products and reduce third-party or clinical researcher interest and support of proposed trials. These interruptions or failures could also impede commercialization of our product candidates and impair our competitive position.
Ultimately, we could be prevented from commercializing a product, or be forced, by court order or otherwise, to 46 cease some or all aspects of our business operations, if, as a result of actual or threatened patent or other intellectual property claims, we are unable to enter into licenses on acceptable terms.
Ultimately, we could be prevented from commercializing a product, or be forced, by court order or otherwise, to cease some or all aspects of our business operations, if, as a result of actual or threatened patent or other intellectual property claims, we are unable to enter into licenses on acceptable terms.
To the extent that any disruption or security breach were to result in a loss of or damage to data or applications, or inappropriate disclosure of confidential or proprietary information or personal health 50 information, we could incur substantial liability, our reputation would be damaged, and the further development of our product candidates could be delayed.
To the extent that any disruption or security breach were to result in a loss of or damage to data or applications, or inappropriate disclosure of confidential or proprietary information or personal health information, we could incur substantial liability, our reputation would be damaged, and the further development of our product candidates could be delayed.
In addition, these potential severance payments may discourage or prevent third parties from seeking a business combination with us. 53 Because we do not anticipate paying cash dividends on our common stock for the foreseeable future, investors in our common stock may never receive a return on their investment.
In addition, these potential severance payments may discourage or prevent third parties from seeking a business combination with us. Because we do not anticipate paying cash dividends on our common stock for the foreseeable future, investors in our common stock may never receive a return on their investment.
In addition, our contract manufacturers and researchers in China may be subject to U.S. legislation, sanctions, trade restrictions and other foreign regulatory requirements, which could increase the cost or reduce the supply of material available to us or delay or prevent the procurement or supply of such material.
In addition, our contract manufacturers and researchers in China may be subject to U.S. legislation, sanctions, tariffs, trade restrictions and other foreign regulatory requirements, which could increase the cost or reduce the supply of material available to us or delay or prevent the procurement or supply of such material.
Luly, Or, or Rottinghaus has informed us to date that he expects to retire or resign in the near future, the loss of the services of any of these individuals or one or more of our other members of senior management could delay or prevent the successful development of our product candidates.
Luly, Or, Kieffer or Rottinghaus has informed us to date that he expects to retire or resign in the near future, the loss of the services of any of these individuals or one or more of our other members of senior management could delay or prevent the successful development of our product candidates.
Further, we may be exposed to fluctuations in the value of the local currency in China. Future appreciation of the local currency could increase our costs. In addition, our labor costs could continue to rise as wage rates increase due to increased demand for skilled laborers and the availability of skilled labor declines in China.
Further, we 44 may be exposed to fluctuations in the value of the local currency in China. Future appreciation of the local currency could increase our costs. In addition, our labor costs could continue to rise as wage rates increase due to increased demand for skilled laborers and the availability of skilled labor declines in China.
These licenses may not be available on acceptable terms, or at all. Even if we were able to obtain a license, the rights may be nonexclusive, which could result in our competitors gaining access to the same intellectual property.
These licenses may not be available on acceptable terms, or at all. Even if we were able to obtain a 46 license, the rights may be nonexclusive, which could result in our competitors gaining access to the same intellectual property.
This, in turn, could prevent us from commercializing our product candidates. Results of earlier clinical trials may not be predictive of the results of later-stage clinical trials. To date we have only tested our product candidates through initial Phase 2 studies.
This, in turn, could prevent us from commercializing our product candidates. Results of earlier clinical trials may not be predictive of the results of later-stage clinical trials. To date we have only tested our product candidates through Phase 2 clinical studies.
In the United States, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Affordability Reconciliation Act of 2010, collectively referred to as the ACA, has significantly changed the way healthcare is financed by both governmental and private insurers.
In the United States, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, collectively referred to as the ACA, has significantly changed the way healthcare is financed by both governmental and private insurers.
We cannot be sure that reimbursement will be available for any product that we may commercialize and, if reimbursement is available, the level of 40 reimbursement. In addition, reimbursement may impact the demand for, or the price of, MAVYRET/MAVIRET or any product candidate for which we may obtain marketing approval.
We cannot be sure that reimbursement will be available for any product that we may commercialize and, if reimbursement is available, the level of reimbursement. In addition, reimbursement may impact the demand for, or the price of, MAVYRET/MAVIRET or any product candidate for which we may obtain marketing approval.
Our future capital requirements depend on many factors, including: • the number and characteristics of our research and development programs; • the scope, progress, results and costs of researching and developing our product candidates on our own, including conducting advanced clinical trials; • our ability to establish new collaborations, licensing or other arrangements, if any, and the financial terms of such arrangements; • the amount of our retained portion of royalties generated from MAVYRET/MAVIRET sales under our existing collaboration with AbbVie; • delays and additional expenses in our clinical trials; • the cost of manufacturing our product candidates for clinical development and any products we successfully commercialize independently; • opportunities to in-license or otherwise acquire new technologies and therapeutic candidates ; • 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; • the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently; • the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs; • the timing and amount of any sales of our product candidates, if any, or royalties thereon ; • the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation ; and • potential fluctuations in foreign currency exchange rates.
Our future capital requirements depend on many factors, including: • the number and characteristics of our research and development programs; • the scope, progress, results and costs of researching and developing our product candidates on our own, including conducting advanced clinical trials; • our ability to establish new collaborations, licensing or other arrangements, if any, and the financial terms of such arrangements; • the amount of our retained portion of royalties generated from MAVYRET/MAVIRET sales under our existing collaboration with AbbVie; • delays and additional expenses in our clinical trials; • the cost of manufacturing our product candidates for clinical development and any products we successfully commercialize independently; • opportunities to in-license or otherwise acquire new technologies and therapeutic candidates; • costs associated with prosecuting our patent infringement litigation in the United States and Europe regarding use of a coronavirus 3CL protease inhibitor in Paxlovid, Pfizer’s antiviral treatment for COVID-19; • the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently; • the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs; • the timing and amount of any sales of our product candidates, if any, or royalties thereon; • the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation; and • potential fluctuations in foreign currency exchange rates.
In addition to HIPAA and GDPR, numerous other federal and state laws, including, without limitation, state security breach notification laws, state health information privacy laws and federal and state consumer protection laws, govern the collection, use, disclosure and storage of personal information.
In addition to HIPAA 50 and GDPR, numerous other federal and state laws, including, without limitation, state security breach notification laws, state health information privacy laws and federal and state consumer protection laws, govern the collection, use, disclosure and storage of personal information.
For example, to execute our business plan for the development of our independent RSV programs, we will need to successfully: • execute clinical development of our product candidates and demonstrate acceptable safety and efficacy for them alone or in combination with other drugs or drug candidates; • obtain required regulatory approvals for the development and commercialization of our product candidates; 34 • develop and maintain any future collaborations we may enter into for any of these programs; • obtain and maintain patent protection for our product candidates and freedom from infringement of intellectual property of others; • establish acceptable commercial manufacturing arrangements with third-party manufacturers; • build and maintain robust sales, distribution and marketing capabilities, either independently or in collaboration with future collaborators; • gain market acceptance for our product candidates among physicians, payors and patients; and • manage our spending as costs and expenses increase due to clinical trials, regulatory approvals and commercialization.
For example, to execute our business plan for the development of our clinical-stage programs, we will need to successfully: • execute clinical development of our product candidates and demonstrate acceptable safety and efficacy for them alone or in combination with other drugs or drug candidates; • obtain required regulatory approvals for the development and commercialization of our product candidates; • develop and maintain any future collaborations we may enter into for any of these programs; 34 • obtain and maintain patent protection for our product candidates and freedom from infringement of intellectual property of others; • establish acceptable commercial manufacturing arrangements with third-party manufacturers; • build and maintain robust sales, distribution and marketing capabilities, either independently or in collaboration with future collaborators; • gain market acceptance for our product candidates among physicians, payors and patients; and • manage our spending as costs and expenses increase due to clinical trials, regulatory approvals and commercialization.
If reimbursement is not available or is available only to limited levels, we may not be able to successfully commercialize any product candidate for which we may seek marketing approval.
If reimbursement is not available or is available only to 40 limited levels, we may not be able to successfully commercialize any product candidate for which we may seek marketing approval.
For example, if we were to initiate legal proceedings against a third party to enforce a patent covering one of our product candidates, the defendant could counterclaim that our patent is invalid and/or unenforceable, as has been asserted by Pfizer in our patent infringement suit regarding Paxlovid, Pfizer’s antiviral treatment for COVID-19.
For example, if we were to initiate legal proceedings against a third party to enforce a patent covering one of our product candidates, the defendant could counterclaim that our patent is invalid and/or unenforceable, as has been asserted by Pfizer in our patent infringement suit in the United States regarding Paxlovid, Pfizer’s antiviral treatment for COVID-19.
In patent litigation in the United States and in some other jurisdictions, defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, for example, lack of novelty, obviousness or non-enablement.
In patent litigation in the United States, Europe and in other jurisdictions, defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, for example, lack of novelty, obviousness or non-enablement.
Our executive officers are parties to employment agreements that provide for aggregate cash payments of up to approximately $6.4 million for severance and other non-equity-based benefits in the event of a termination of employment in connection with a change of control of our company. The payment of these severance benefits could harm our company’s financial condition and results.
Our executive officers are parties to employment agreements that provide for aggregate cash payments of up to approximately $6.3 million for severance and other non-equity-based benefits in the event of a termination of employment in connection with a change of control of our company. The payment of these severance benefits could harm our company’s 53 financial condition and results.
Senate, target U.S. government contracts, grants, and loans for entities that use equipment and services from certain named Chinese biotech companies, and authorize the U.S. government to name additional Chinese biotechnology companies of concern.
Congress, target U.S. government contracts, grants, and loans for entities that use equipment and services from certain named Chinese biotech companies, and authorize the U.S. government to name additional Chinese biotechnology companies of concern.
Any efforts to enforce our intellectual property rights are also likely to be costly, as has been and may continue to be the case with the Pfizer suit, and may divert the efforts of our scientific and management personnel.
Any efforts to enforce our intellectual property rights are also likely to be costly, as has been and may continue to be the case with the Pfizer litigation, and may divert the efforts of our scientific and management personnel.
For AD, the moderate-severe atopic dermatitis treatment landscape is dominated by biologics targeting the IL-4 and/or IL-13 pathway (e.g., DUPIXENT ® (dupilumab) and ADBRY ® (tralokinumab-ldrm)), with JAK inhibitors (e.g., RINVOQ ® (upadacitinib) and CIBINQO ® (abrocitinib)) as the only oral option. Multiple oral mechanisms are in development, including inhibitors of MRGPRX2, IRAK4, STAT6, RASP and PKM2.
For AD, the moderate-severe atopic dermatitis treatment landscape is dominated by biologics targeting the IL-4 and/or IL-13 pathway (e.g., DUPIXENT ® (dupilumab), ADBRY ® (tralokinumab-ldrm), and EBGLYSS™ (lebrikizumab-lbkz)), with JAK inhibitors (e.g., RINVOQ ® (upadacitinib) and CIBINQO ® (abrocitinib)) as the only oral option. Multiple oral mechanisms are in development, including inhibitors of MRGPRX2, IRAK4, ITK, STAT6, RASP and PKM2.
In addition, as of September 30, 2024, we had 5.2 million and 0.6 million shares of common stock that are subject to outstanding options and restricted stock unit awards, respectively, under our outstanding equity plans eligible for sale in the public market to the extent permitted by the provisions of various vesting schedules, and Rule 144 under the Securities Act.
In addition, as of September 30, 2025, we had 5.8 million and 0.6 million shares of common stock that are subject to outstanding options and restricted stock unit awards, respectively, under our outstanding equity plans eligible for sale in the public market to the extent permitted by the provisions of various vesting schedules, and Rule 144 under the Securities Act.
In addition, several states have not implemented the provisions of the ACA that involve the expansion of Medicaid-eligibility for low-income adults. While the United States Supreme Court recently rejected the latest challenge to the constitutionality of the ACA, it is possible that other legislative efforts may seek to modify it.
In addition, several states have not implemented the provisions of the ACA that involve the expansion of Medicaid-eligibility for low-income adults. While the United States Supreme Court rejected the most recent challenge to the constitutionality of the ACA, it is possible that other legislative efforts may seek to modify it.
If we are not successful in developing zelicapavir or EDP-323, or discovering and developing KIT and STAT6 inhibitors, or in obtaining a partner to advance EDP-235 or EDP-514, or in discovering further product candidates, our ability to expand our business and achieve our strategic objectives will be impaired. Much of our internal research is at preclinical stages.
If we are not successful in discovering and developing KIT and STAT6 inhibitors, or in obtaining one or more partners to advance zelicapavir, EDP-323, EDP-235 or EDP-514, or in discovering further product candidates, our ability to expand our business and achieve our strategic objectives will be impaired. Much of our internal research is at preclinical stages.
These sales, or the perception in the market that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock. As of September 30, 2024 we had 21.2 million shares of common stock outstanding.
These sales, or the perception in the market that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock. As of September 30, 2025 we had 21.4 million shares of common stock outstanding.
Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things: • restrictions on the marketing or manufacturing of the product, withdrawal of the product from the market or voluntary or mandatory product recalls; • fines, warning letters or holds on any post-approval clinical trials; • refusal by the FDA to approve pending applications or supplements to approved applications filed by us, or suspension or revocation of product license approvals; • product seizure or detention, or refusal to permit the import or export of products; and • injunctions or the imposition of civil or criminal penalties. 39 We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad.
Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things: • restrictions on the marketing or manufacturing of the product, withdrawal of the product from the market or voluntary or mandatory product recalls; • fines, warning letters or holds on any post-approval clinical trials; • refusal by the FDA to approve pending applications or supplements to approved applications filed by us, or suspension or revocation of product license approvals; • product seizure or detention, or refusal to permit the import or export of products; and • injunctions or the imposition of civil or criminal penalties.
For COVID, there are two oral antiviral treatments for non-hospitalized, high-risk patients with SARS-CoV-2 infection: PAXLOVID™, a 3CL protease inhibitor (nirmatrelvir) boosted with ritonavir (full approval), and LAGEVRIO™ (molnupiravir), a polymerase inhibitor (Emergency Use Authorization). There are no oral direct acting antivirals for the treatment of SARS-CoV-2 in late stage global clinical trials.
For COVID, there are two oral antiviral treatments for non-hospitalized, high-risk patients with SARS-CoV-2 infection: PAXLOVID™, a 3CL protease inhibitor (nirmatrelvir) boosted with ritonavir (full approval), and LAGEVRIO™ (molnupiravir), a polymerase inhibitor (Emergency Use Authorization). The most advanced direct acting oral antiviral for the treatment of high-risk patients with SARS-CoV-2 is in Phase 3 (ibuzatrelvir).
We may incur substantial costs to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.
We may incur substantial costs to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts.
In addition, our ability to apply our proprietary technologies to develop proprietary compounds will depend on our ability to establish and maintain licensing arrangements or other collaborative arrangements with the holders of proprietary rights to such compounds. We may not be able to establish such arrangements on favorable terms or at all, and our collaborative arrangements may not be successful.
In addition, our ability to apply our proprietary technologies to develop proprietary compounds will depend on our ability to establish and maintain licensing arrangements or other collaborative arrangements with the holders of proprietary rights to such compounds.
If any of the physicians or other providers or entities with whom we expect to do business, including our collaborators, are found not to be in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs, which could also materially affect our business.
If any of the physicians or other providers or entities with whom we expect to do business, including our collaborators, are found not to be in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs, which could also materially affect our business. 51 Risks Related to Our Common Stock Our stock price has been, and is likely to continue to be, volatile, and thus our stockholders could incur substantial losses.
We maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials. This insurance may not provide adequate coverage against 54 potential liabilities.
Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions. 54 We maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials. This insurance may not provide adequate coverage against potential liabilities.
If securities or industry analysts do not publish research, or publish inaccurate or unfavorable research about our business, our stock price and trading volume would likely decline. 52 The trading market for our common stock will depend in part on the research and reports that securities or industry analysts publish about us or our business.
The trading market for our common stock will depend in part on the research and reports that securities or industry analysts publish about us or our business.
If AbbVie acts in a manner that is not in our best interest, then it could adversely affect our royalty revenues.
AbbVie may also make decisions with which we do not agree. If AbbVie acts in a manner that is not in our best interest, then it could adversely affect our royalty revenues.
Foreign governments tend to impose strict price controls, which may adversely affect our future profitability. In most foreign countries, particularly in the European Union and Japan, prescription drug pricing and/or reimbursement is subject to governmental control.
The implementation of cost containment measures or other healthcare reforms may limit our ability to generate revenue, maintain profitability or commercialize our product candidates. Foreign governments tend to impose strict price controls, which may adversely affect our future profitability. In most foreign countries, particularly in the European Union and Japan, prescription drug pricing and/or reimbursement is subject to governmental control.
For example, in 2018 AbbVie entered into a royalty-free licensing agreement with the Medicines Patent Pool to accelerate access to generic versions of MAVYRET/MAVIRET in 99 low- and middle-income countries and territories. AbbVie may also make decisions with which we do not agree.
In addition, AbbVie has the right to make decisions regarding the commercialization of licensed products without consulting us. For example, in 2018 AbbVie entered into a royalty-free licensing agreement with the Medicines Patent Pool to accelerate access to generic versions of MAVYRET/MAVIRET in 99 low- and middle-income countries and territories.
AstraZeneca/Sanofi (BEYFORTUS ® ) and Merck (Clesrovimab – Phase 3 complete) are developing long-acting monoclonal antibodies for prophylaxis use in infants, and Pfizer has an approved maternal vaccine (ABRYSVO ® ), all of which provide passive immunity to infants. Sanofi is also evaluating a vaccine in infants and toddlers (RSVt vaccine – Phase 3).
AstraZeneca/Sanofi (BEYFORTUS ® ) and Merck (ENFLONSIA™) have approved long-acting monoclonal antibodies for prophylaxis use in infants, and Pfizer has an approved maternal vaccine (ABRYSVO ® ), all of which provide passive immunity to infants.
Our commercial success will depend, in large part, on our ability to obtain and maintain patent and other intellectual property protection with respect to our product candidates.
We could be unsuccessful in obtaining or maintaining adequate patent protection for one or more of our product candidates. Our commercial success will depend, in large part, on our ability to obtain and maintain patent and other intellectual property protection with respect to our product candidates.
Depending on decisions and actions by the United States Congress, the federal courts, the United States Patent and Trademark Office, and their respective foreign counterparts, the laws and regulations governing patents could change in unpredictable ways that could weaken our ability to obtain new patents or to maintain and enforce our existing patents and patents that we might obtain in the future.
Depending on decisions and actions by the United States Congress, the federal courts, the United States Patent and Trademark Office, and their respective foreign counterparts, the laws and regulations governing patents could change in unpredictable ways that could weaken our ability to obtain new patents or to maintain and enforce our existing patents and patents that we might obtain in the future. 49 Risks Related to Our Industry If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit commercialization of our product candidates.
We are highly dependent upon our senior management, particularly Jay R. Luly, Ph.D., our Chief Executive Officer and President, Yat Sun Or, Ph.D., our Senior Vice President, Research and Development and Chief Scientific Officer, and Scott T. Rottinghaus, M.D., our Senior Vice President and Chief Medical Officer, as well as other employees and consultants. Although none of Drs.
We are highly dependent upon our senior management, particularly Jay R. Luly, Ph.D., our Chief Executive Officer and President, Yat Sun Or, Ph.D., our Senior Vice President, Research and Development and Chief Scientific Officer, Tara Kieffer, our Chief Product Strategy Officer, and Scott T.
Specifically for KIT inhibitors, there are companies with antibodies in development, including Celldex (barzolvolimab - Phase 3) and Jasper (briquilimab - Phase 1b/2a), as well as companies with oral, small molecules in early clinical or preclinical development, including Third Harmonic, Blueprint, Arcus, and Alivexis.
For CSU, there are a number of different mechanisms being explored, including inhibitors of IL-4R, IgE, BTK, and MRGPRX2. Specifically for KIT inhibitors, there are companies with antibodies in development, including Celldex (barzolvolimab - Phase 3) and Jasper (briquilimab - Phase 1b/2a), as well as companies with oral, small molecules in early clinical or preclinical development, including Sanofi/Blueprint.
If these additional shares of common stock are sold, or it is perceived that they will be sold, in the public market, the trading price of our common stock could decline.
If these additional shares of common stock are sold, or it is perceived that they will be sold, in the public market, the trading price of our common stock could decline. 52 If securities or industry analysts do not publish research, or publish inaccurate or unfavorable research about our business, our stock price and trading volume would likely decline.
Any of these matters could materially and adversely affect our business and results of operations despite our ongoing efforts to mitigate these risks. For example, the recently proposed BIOSECURE Act that was passed by the U.S. House of Representatives in September 2024, as well as a substantially similar bill in the U.S.
Any of these matters could materially and adversely affect our business and results of operations despite our ongoing efforts to mitigate these risks. For example, the proposed BIOSECURE Act, currently under consideration by the U.S.
Risks Related to Our Industry If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit commercialization of our product candidates. 49 We face an inherent risk of product liability as a result of the clinical testing of our product candidates, and we will face an even greater risk if we commercialize any product candidates.
We face an inherent risk of product liability as a result of the clinical testing of our product candidates, and we will face an even greater risk if we commercialize any product candidates.
Accordingly, we will need to obtain additional funding to support our operations. Additional funds may not be available if and when we need them, on terms that are acceptable to us, or at all. Our ability to raise funds will depend on financial, economic and market conditions and other factors, many of which are beyond our control.
Accordingly, we will need to obtain additional funding to support our operations. In October 2025, we completed a public offering of our common stock, resulting in gross proceeds of approximately $74.8 million. Additional funds may not be available if and when we need them, on terms that are acceptable to us, or at all.
We face significant competition in seeking appropriate collaborators and the negotiation process is time-consuming and complex.
We are also evaluating potential partnership opportunities to advance our RSV programs to the next stage of clinical development. We face significant competition in seeking appropriate collaborators and the negotiation process is time-consuming and complex.
From October 1, 2019 through September 30, 2024, the daily closing price of our common stock on the NASDAQ Global Select Market has ranged from $8.18 to $97.37.
Our stock price has been volatile and could be subject to wide fluctuations in response to various factors, many of which are beyond our control. From October 1, 2020 through September 30, 2025, the daily closing price of our common stock on the Nasdaq Global Select Market has ranged from $4.26 to $97.37.
Risks Related to Our Intellectual Property Rights 45 We are competing to develop intellectual property in areas of small-molecule drug development that are highly competitive. We could be unsuccessful in obtaining or maintaining adequate patent protection for one or more of our product candidates.
We may not be able to establish such arrangements on favorable terms or at all, and our collaborative arrangements may not be successful. 45 Risks Related to Our Intellectual Property Rights We are competing to develop intellectual property in areas of small-molecule drug development that are highly competitive.
There are also two approved RSV vaccines for adults 33 over 60 years of age (Pfizer/ABRYSVO ® and Moderna/Mresvia ® ) and one approved RSV vaccine for adults over 50 years of age (GSK/AREXVY ® ). For CSU, there are a number of different mechanisms being explored, including inhibitors of IL-4R, IgE, BTK, SIGLEC-6, and MRGPRX2.
There are also two approved RSV vaccines for high-risk adults age 18 – 59 years and for all adults age 60 years and above (Pfizer/ABRYSVO ® and 33 Moderna/mRESVIA ® ) and one approved RSV vaccine for high-risk adults age 50-59 years and in adults age 60 years and older (GSK/AREXVY ® ).
There may also be fluctuations in AbbVie’s market share over time due to these and other competitive actions by Gilead. In addition, in light of continued fiscal crises experienced by several countries in the European Union and Japan, governments have announced or implemented measures to manage and reduce healthcare expenditures.
In addition, in light of continued fiscal crises experienced by several countries in the European Union and Japan, governments have announced or implemented measures to manage and reduce healthcare expenditures. AbbVie may experience global pricing pressure for its MAVYRET/MAVIRET regimen from such measures, which may be reflected in larger discounts or rebates on its regimens or delayed reimbursement.
The latest stage oral assets are in Ph2 (Incyte MRGPRX2 – Ph2a; Sanofi/Kymera IRAK4 – Ph2). For STAT6 inhibitors specifically, companies with oral assets in development include Kymera (KT-621 – Phase 1) and Sanofi/Recludix (preclinical). In the chronic HCV market, we expect AbbVie’s MAVYRET/MAVIRET to continue to face intense competition due to existing approved HCV products.
In the HCV market, we expect AbbVie’s MAVYRET/MAVIRET to continue to face intense competition due to existing approved HCV products.
We expect to experience pricing pressures in connection with the sale of any products that we develop or that are being commercialized under our collaboration with AbbVie. The implementation of cost containment measures or other healthcare reforms may limit our ability to generate revenue, maintain profitability or commercialize our product candidates.
For example, in recent years, federal and state governments have proposed or implemented MFN pricing models that tie reimbursement rates for certain drugs to the lowest prices paid by other countries. We expect to experience pricing pressures in connection with the sale of any products that we develop or that are being commercialized under our collaboration with AbbVie.
Removed
Any such change in formulary coverage, discounts or rebates or reimbursement for MAVYRET/MAVIRET would negatively affect the demand for this regimen and our royalty revenue derived from its sales. In addition, AbbVie has the right to make decisions regarding the commercialization of licensed products without consulting us.
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Our ability to raise funds will depend on financial, economic and market conditions and other factors, many of which are beyond our control.
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Risks Related to Our Common Stock Our stock price has been, and is likely to continue to be, volatile, and thus our stockholders could incur substantial losses. 51 Our stock price has been volatile and could be subject to wide fluctuations in response to various factors, many of which are beyond our control.
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There may also be fluctuations in AbbVie’s market share over time due to these and other competitive actions by Gilead. In recent years, federal and state governments have proposed or implemented Most Favored Nation, or MFN, pricing models that tie reimbursement rates for certain drugs to the lowest prices paid by other countries.
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The latest stage oral assets being evaluated in moderate-severe AD patients are in Phase 2b (Evommune MRGPRX2) and Phase 1 (Corvus ITKl; Kymera STAT6)). For STAT6 inhibitors specifically, companies with oral assets in preclinical development include Sanofi/Recludix, J&J/Katen, Gilead/LEO, DeepCure and JW Pharma.
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Rottinghaus, M.D., our Senior Vice President and Chief Medical Officer, as well as other employees and consultants. Although none of Drs.
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We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad.

Item 1C. Cybersecurity

Cybersecurity — threats and controls disclosure

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Biggest changeHowever, such insurance may not be sufficient to cover us against all possible claims related to security breaches, cyber-attacks and other related breaches.
Biggest changeHowever, such insurance may not be sufficient to cover us against all possible claims related to security breaches, cyber-attacks and other related breaches. As of the date of this report, we have not identified cybersecurity threats that we believe are reasonably likely to materially affect us.
Part of our IRP also calls for the elevation of any necessary incidents to upper management in a timely manner whenever they occur. We have also formed a steering committee, composed of IT staff and relevant business leaders responsible for the Company’s material information, including commercially sensitive data.
Part of our IRP also calls for the elevation of any material incidents to upper management in a timely manner whenever they occur. We have also formed a steering committee, composed of IT staff and relevant business leaders responsible for the Company’s material information, including commercially sensitive data.
We have retained a seasoned virtual Information Security Officer (“vISO”) to assist and guide our IT organization in maintaining and evolving a comprehensive and robust cyber security environment.
We have retained an industry expert to be our virtual Information Security Officer (“vISO”) to assist and guide our IT organization in maintaining and evolving a comprehensive and robust cyber security environment.
Our current environment contains no known risks from cybersecurity threats that could materially impact our business operations, financials, or public reputation. 56 Cybersecurity Governance and Oversight The Board of Directors has assigned the Audit Committee to be responsible for reviewing our cybersecurity risk management and strategy program and is presented, at least annually, with a review of our environment and reported incidents.
However, cybersecurity risk is dynamic, and future incidents could materially affect our operations, financial condition, or reputation. 56 Cybersecurity Governance and Oversight The Board of Directors has assigned the Audit Committee to be responsible for reviewing our cybersecurity risk management and strategy program and is presented, at least annually, with a review of our environment and reported incidents.

Item 5. Market for Registrant's Common Equity

Market for Common Equity — stock, dividends, buybacks

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Biggest changeThe following table shows the high and low sales price for our common stock as reported by The NASDAQ Global Select Market for the quarterly periods in the fiscal years ended September 30, 2024 and 2023: Fiscal 2024 High Low First Quarter $ 11.07 $ 8.08 Second Quarter $ 17.76 $ 9.24 Third Quarter $ 17.80 $ 11.28 Fourth Quarter $ 17.24 $ 9.90 Fiscal 2023 High Low First Quarter $ 54.20 $ 39.60 Second Quarter $ 62.06 $ 38.16 Third Quarter $ 41.45 $ 19.91 Fourth Quarter $ 22.15 $ 11.03 We have never declared or paid cash dividends on our common stock, and we do not expect to declare or pay any cash dividends for the foreseeable future. 58 Performance Graph (1) The following graph shows a comparison from September 30, 2019 through September 30, 2024 of cumulative total return on assumed investments of $100.00 in cash in each of our common stock, the NASDAQ Composite Index and the NASDAQ Biotechnology Index.
Biggest changeWe have never declared or paid cash dividends on our common stock, and we do not expect to declare or pay any cash dividends for the foreseeable future. 58 Performance Graph (1) The following graph shows a comparison from September 30, 2020 through September 30, 2025 of cumulative total return on assumed investments of $100.00 in cash in each of our common stock, the Nasdaq Composite Index and the Nasdaq Biotechnology Index.
COMPARISON OF FIVE YEARS CUMULATIVE TOTAL RETURN Among Enanta Pharmaceuticals, Inc., the NASDAQ Composite Index, and the NASDAQ Biotechnology Index (1) This performance graph shall not be deemed to be “soliciting material” or to be “filed” with the SEC for purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, or otherwise subject to the liabilities under that Section, and shall not be deemed incorporated by reference into any filing of Enanta Pharmaceuticals, Inc. under the Securities Act of 1933, as amended.
COMPARISON OF FIVE YEARS CUMULATIVE TOTAL RETURN Among Enanta Pharmaceuticals, Inc., the Nasdaq Composite Index, and the Nasdaq Biotechnology Index (1) This performance graph shall not be deemed to be “soliciting material” or to be “filed” with the SEC for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities under that Section, and shall not be deemed incorporated by reference into any filing of Enanta Pharmaceuticals, Inc. under the Securities Act of 1933, as amended.
ITEM 5. MARKET FOR THE COMPANY'S COMMON EQUITY, RELATED STO CKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES Market and Stockholder Information Our common stock has been listed on The NASDAQ Global Select Market under the symbol “ENTA” since March 21, 2013 and we had 17 stockholders of record as of November 12, 2024.
ITEM 5. MARKET FOR THE COMPANY'S COMMON EQUITY, RELATED STO CKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES Market Information Our common stock has been listed on The Nasdaq Global Select Market under the symbol “ENTA” since March 21, 2013. Holders of Record We had 12 stockholders of record as of November 11, 2025.
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This number does not include stockholders for whom shares are held in “nominee” or “street” name.

Item 7. Management's Discussion & Analysis

Management's Discussion & Analysis (MD&A) — revenue / margin commentary

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Biggest changeOur initial immunology targets involve the following mechanisms of immune response: • The receptor tyrosine kinase, known as KIT, which is critical for regulating mast cell activity; and • 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.
Biggest changeOur initial immunology targets involve the following mechanisms of immune response: • 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 • 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.
Our future capital requirements are difficult to forecast and will depend on many factors, including: • the number and characteristics of our research and development programs; • the scope, progress, results and costs of researching and developing our product candidates on our own, including conducting advanced clinical trials; • our ability to establish new collaborations, licensing or other arrangements, if any, and the financial terms of such arrangements; • the amount of our retained portion of royalties generated from MAVYRET/MAVIRET sales under our existing collaboration with AbbVie; • delays and additional expenses in our clinical trials; • the cost of manufacturing our product candidates for clinical development and any products we successfully commercialize independently; • opportunities to in-license or otherwise acquire new technologies and therapeutic candidates; • 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; • the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently; • the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs; • the timing and amount of any sales of our product candidates, if any, or royalties thereon; • the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation; and • potential fluctuations in foreign currency exchange rates.
Our future capital requirements are difficult to forecast and will depend on many factors, including: • the number and characteristics of our research and development programs; • the scope, progress, results and costs of researching and developing our product candidates on our own, including conducting advanced clinical trials; • our ability to establish new collaborations, licensing or other arrangements, if any, and the financial terms of such arrangements; • the amount of our retained portion of royalties generated from MAVYRET/MAVIRET sales under our existing collaboration with AbbVie; • delays and additional expenses in our clinical trials; • the cost of manufacturing our product candidates for clinical development and any products we successfully commercialize independently; • opportunities to in-license or otherwise acquire new technologies and therapeutic candidates; • 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; • the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently; • the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs; • the timing and amount of any sales of our product candidates, if any, or royalties thereon; • the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation; and • potential fluctuations in foreign currency exchange rates.
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. We expect that general and administrative expenses may increase in the long term.
General and administrative expenses also include allocated facility-related costs not otherwise included in research and development expenses, directors’ and officers’ liability insurance premiums, professional fees for auditing, tax, and legal services, patent expenses and litigation expenses associated with prosecuting our patent infringement litigation. We expect that general and administrative expenses may increase in the long term.
Upon gaining access to the 4 Kingsbury Avenue building, we capitalized a right-of-use asset and lease liability of approximately $32 million on our consolidated balance sheets which reflects our fixed base rent payments, net of approximately $15 69 million of a tenant improvement allowance provided by the landlord, over the 10-year term of the lease.
Upon gaining access to the 4 Kingsbury Avenue building, we capitalized a right-of-use asset and lease liability of approximately $32 million on our consolidated balance sheets which reflects our fixed base rent payments, net of approximately $15 million of a 67 tenant improvement allowance provided by the landlord, over the 10-year term of the lease.
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 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.
Management’s Discussion and Analysis of Financial Condition and Results of Operations—Results of Operations—Comparison of the Years Ended September 30, 2023 and 2022 included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2023.
Management’s Discussion and Analysis of Financial Condition and Results of Operations—Results of Operations—Comparison of the Years Ended September 30, 2024 and 2023 included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2024.
Virology 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.
Virology We discovered glecaprevir, the second of two antiviral protease inhibitors developed through our collaboration with AbbVie for the treatment of acute or chronic infection with hepatitis C virus, or HCV.
Contractual Obligations and Commitments Facility Leases As of the date of this report, we lease space in Watertown, Massachusetts, under three separate lease agreements with one landlord.
Contractual Obligations and Commitments Facility Leases As of the date of this report, we lease space in Watertown, Massachusetts, under two separate lease agreements with one landlord.
Comparison of the Years Ended September 30, 2023 and 2022 For a discussion of our results of operations for the year ended September 30, 2023, as compared to the year ended September 30, 2022, see Item 7.
Comparison of the Years Ended September 30, 2024 and 2023 For a discussion of our results of operations for the year ended September 30, 2024, as compared to the year ended September 30, 2023, see Item 7.
Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the “Risk Factors” section of this Annual Report on Form 10-K. Overview We are a biotechnology company that uses our robust, chemistry-driven approach and drug discovery capabilities to discover and develop small molecule drugs with an emphasis on virology and immunology.
Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the “Risk Factors” section of this Annual Report on Form 10-K. Overview We are a biotechnology company that uses our robust, chemistry-driven approach and drug discovery capabilities to discover and develop small molecule drugs for virology and immunology indications.
Preferred Stock 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.
Preferred Stock As of September 30, 2025, we had 1.9 million outstanding shares of Series 1 nonconvertible preferred stock, all of which we classified as a long-term liability on our consolidated balance sheet and recorded at fair value of $1.3 million.
When billing terms under these contracts do not coincide with the timing of when the work is performed, we are required to make estimates of our outstanding obligations to those third parties as of period-end.
We expense the cost of each contract as the work is performed. When billing terms under these contracts do not coincide with the timing of when the work is performed, we are required to make estimates of our outstanding obligations to those third parties as of period-end.
To date we have not experienced a significant impact of inflation on general and administrative expenses, but we anticipate inflation may impact future periods. Other Income (Expense) Other income (expense) consists of interest expense, interest and investment income, net and the change in fair value of our outstanding Series 1 nonconvertible preferred stock.
To date we have not experienced a significant impact of inflation on general and administrative expenses. Other Income (Expense) Other income (expense) consists of interest expense, interest and investment income, net and the change in fair value of our outstanding Series 1 nonconvertible preferred stock.
Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Cash Flows included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2023. 68 Funding Requirements As of September 30, 2024, we had $248.2 million in cash, cash equivalents and short-term marketable securities.
Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Cash Flows included in our Annual Report on Form 10-K for the fiscal year ended September 30, 2024. 66 Funding Requirements As of September 30, 2025, we had $188.9 million in cash, cash equivalents and short-term marketable securities.
Liquidity and Capital Resources We fund our operations with cash flows from our retained portion of our royalty revenue and our existing financial resources. At September 30, 2024, our principal sources of liquidity were cash and cash equivalents and short-term marketable securities of $248.2 million.
Liquidity and Capital Resources We fund our operations with cash flows from our retained portion of our royalty revenue and our existing financial resources. At September 30, 2025, our principal sources of liquidity were cash and cash equivalents and short-term marketable securities of $188.9 million.
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.
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.
Net cash provided by (used in) financing activities 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.
Net cash (used in) provided by financing activities Cash used in financing activities was $26.6 million for the year ended September 30, 2025 as compared to cash used in financing activities of $27.6 million for the same period in 2024.
We currently plan to focus our immunology drug development efforts on the following disease indications: • 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 • Atopic dermatitis, or AD, a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin with significant quality of life impacts such as leading a limited lifestyle, avoidance of social interactions and a reduced range of activities, with AD affecting 7.3% of the US adult population, of whom ~40% have moderate to severe disease. 60 As of September 30, 2024, we had $248.2 million in cash, cash equivalents and short-term marketable securities.
We currently plan to focus our initial immunology drug development proof-of-concept efforts on the following disease indications: • 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 • Atopic dermatitis, or AD, a chronic dermatological disease characterized by dry, red, inflamed, irritated and itchy skin with significant quality of life impacts such as leading a limited lifestyle, avoidance of social interactions and a reduced range of activities, with AD affecting 7.3% of the US adult population, of whom ~40% have moderate to severe disease.
As of 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 .
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.
Net cash provided by (used in) investing activities 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.
Net cash provided by (used in) investing activities Cash provided by investing activities was $40.3 million for the year ended September 30, 2025 as compared to cash provided by investing activities of $58.2 million for the same period in 2024.
We will continue to record 100% of HCV royalties earned under the AbbVie Agreement as royalty revenue in our consolidated statements of operations since the AbbVie Agreement has not been amended and is independent of our agreement with OMERS. 66 Research and development expenses Years Ended September 30, 2024 2023 (in thousands) R&D programs: Virology RSV $ 86,367 $ 78,120 COVID-19 4,625 66,082 HBV 371 6,974 Total Virology $ 91,363 $ 151,176 Immunology KIT 19,822 — STAT6 4,691 — Total Immunology $ 24,513 $ — Other Programs NASH 605 4,095 Early discovery 14,995 8,253 Total Other Programs $ 15,600 $ 12,348 Total research and development expenses $ 131,476 $ 163,524 Research and development expenses for the year ended September 30, 2024 decreased by $32.0 million compared to the same period in 2023.
We will continue to record 100% of HCV royalties earned under the AbbVie Agreement as royalty revenue in our consolidated statements of operations since the AbbVie Agreement has not been amended and is independent of our agreement with OMERS. 64 Research and development expenses Years Ended September 30, 2025 2024 2023 (in thousands) R&D programs: Virology RSV $ 59,808 $ 86,367 $ 78,120 COVID-19 587 4,625 66,082 HBV 152 371 6,974 Total Virology $ 60,547 $ 91,363 $ 151,176 Immunology KIT 18,052 19,822 — STAT6 16,614 4,691 — Total Immunology $ 34,666 $ 24,513 $ — Other Programs Early discovery 11,328 14,995 8,253 Other programs for out-licensing 199 605 4,095 Total Other Programs $ 11,527 $ 15,600 $ 12,348 Total research and development expenses $ 106,740 $ 131,476 $ 163,524 Research and development expenses for the year ended September 30, 2025 decreased by $24.7 million compared to the same period in 2024.
Interest and investment income, net 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.
Interest and investment income, net Interest and investment income, net, decreased by $5.3 million for the year ended September 30, 2025, as compared to the same period in 2024.
Other income (expense) Changes in components of other income (expense) were as follows: Interest expense 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.
Other income (expense) Changes in components of other income (expense) were as follows: Interest expense Interest expense decreased by $3.3 million for the year ended September 30, 2025, as compared to the same period in 2024, due to the paydown of our obligation associated with our royalty sale agreement entered into during April 2023 with an affiliate of OMERS.
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.
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.
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.
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.
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.
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.
The following table shows a summary of our cash flows: Years Ended September 30, 2024 2023 2022 (in thousands) Cash provided by (used in): Operating activities $ (78,764 ) $ (103,154 ) $ (84,782 ) Investing activities 58,235 (53,578 ) 54,897 Financing activities (27,626 ) 198,126 20,033 Net (decrease) increase in cash, cash equivalents and restricted cash $ (48,155 ) $ 41,394 $ (9,852 ) Net cash used in operating activities 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 following table shows a summary of our cash flows: Years Ended September 30, 2025 2024 2023 (in thousands) Cash provided by (used in): Operating activities $ (19,272 ) $ (78,764 ) $ (103,154 ) Investing activities 40,347 58,235 (53,578 ) Financing activities (26,618 ) (27,626 ) 198,126 Net (decrease) increase in cash, cash equivalents and restricted cash $ (5,543 ) $ (48,155 ) $ 41,394 Net cash used in operating activities Cash used in operating activities was $19.3 million for the year ended September 30, 2025 as compared to cash used in operating activities of $78.8 million for the same period in 2024.
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.
Based on our operating plan, we believe that our existing cash, cash equivalents and short-term marketable securities as of September 60 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.
The following table is a summary of revenue recognized for the years ended September 30, 2024, 2023, and 2022: Years Ended September 30, 2024 2023 2022 (in thousands) Revenue Royalty revenue $ 67,635 $ 78,204 $ 86,160 License revenue — 1,000 — Total revenue $ 67,635 $ 79,204 $ 86,160 As disclosed above regarding our OMERS royalty sale agreement, we only retain 45.5% of the cash payments from royalties on net sales of MAVYRET/MAVIRET occurring after June 30, 2023 through June 30, 2032, subject to a cap on aggregate payments to OMERS equal to 1.42 times OMERS’ purchase price.
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. 61 The following table is a summary of revenue recognized for the years ended September 30, 2025, 2024, and 2023: Years Ended September 30, 2025 2024 2023 (in thousands) Revenue Royalty revenue $ 65,324 $ 67,635 $ 78,204 License revenue — — 1,000 Total revenue $ 65,324 $ 67,635 $ 79,204 As disclosed above regarding our OMERS royalty sale agreement, we only retain 45.5% of the cash payments from royalties on net sales of MAVYRET/MAVIRET occurring after June 30, 2023 through June 30, 2032, subject to a cap on aggregate payments to OMERS equal to 1.42 times OMERS’ purchase price.
Results of Operations Years Ended September 30, 2024 2023 2022 (in thousands) Revenue $ 67,635 $ 79,204 $ 86,160 Research and development 131,476 163,524 164,522 General and administrative 57,850 52,887 45,482 Interest expense (10,940 ) (5,148 ) — Interest and investment income, net 14,770 11,360 1,573 Change in fair value of Series 1 nonconvertible preferred stock 73 — 83 Income tax benefit (expense) 1,743 (2,821 ) 433 Net loss $ (116,045 ) $ (133,816 ) $ (121,755 ) Comparison of the Years Ended September 30, 2024 and 2023 Revenue We recognized revenue of $67.6 million and $79.2 million during the years ended September 30, 2024 and 2023, respectively.
Results of Operations Years Ended September 30, 2025 2024 2023 (in thousands) Revenue $ 65,324 $ 67,635 $ 79,204 Research and development 106,740 131,476 163,524 General and administrative 43,933 57,850 52,887 Interest expense (7,681 ) (10,940 ) (5,148 ) Interest and investment income, net 9,442 14,770 11,360 Change in fair value of Series 1 nonconvertible preferred stock 39 73 — Income tax benefit (expense) 1,660 1,743 (2,821 ) Net loss $ (81,889 ) $ (116,045 ) $ (133,816 ) Comparison of the Years Ended September 30, 2025 and 2024 Revenue We recognized revenue of $65.3 million and $67.6 million during the years ended September 30, 2025 and 2024, respectively.
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.
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.
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. Year Ended September 30, 2023 For a discussion of our cash flows for the year ended September 30, 2023, see Item 7.
Our cash used in financing activities decreased $1.0 million, driven primarily by lower payments on our royalty sale agreement with OMERS. Year Ended September 30, 2024 For a discussion of our cash flows for the year ended September 30, 2024, see Item 7.
See also Note 2 to the consolidated financial statements included elsewhere in this Annual Report on Form 10-K for information about these critical accounting policies as well as a description of our other significant accounting policies. 65 Research and Development and Pharmaceutical Drug Manufacturing Accruals We have entered into various contracts with third parties to perform research and development and pharmaceutical drug manufacturing.
See also Note 2 to the consolidated financial statements included elsewhere in this Annual Report on Form 10-K for information about these critical accounting policies as well as a description of our other significant accounting policies.
Critical Accounting Policies Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amount of assets, liabilities, equity, revenue, costs and expenses, and related disclosures.
The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amount of assets, liabilities, equity, revenue, costs and expenses, and related disclosures.
General and administrative expenses 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.
General and administrative expenses General and administrative expenses decreased by $13.9 million for the year ended September 30, 2025, compared to the same period in 2024, primarily due to a decrease in legal expenses related to our patent infringement suit against Pfizer and a decrease in stock-based compensation expenses.
We anticipate that we will make determinations as to which development programs to pursue and how much funding to direct to each program on an ongoing basis in response to the preclinical and clinical success and prospects of each product candidate, as well as ongoing assessments of the commercial potential of each product candidate.
We anticipate that we will make determinations as to which development programs to pursue and how much funding to direct to each program on an ongoing basis in response to the preclinical and clinical success and prospects of each product candidate, as well as ongoing assessments of the commercial potential of each product candidate. 62 General and Administrative Expenses General and administrative expenses consist primarily of personnel costs, which include salaries, related benefits and stock-based compensation, of our executive, finance, business and corporate development and other administrative functions.
To date, we have not identified 64 any significant impact of inflation on spending in research and development, but it is uncertain whether there will be inflationary impacts in future periods.
To date, we have not identified any significant impact of inflation on spending in research and development, but it is uncertain whether there will be inflationary impacts in future periods. Our research and drug discovery and development programs are in early stages; therefore, the successful development of our product candidates is highly uncertain and may not result in approved products.
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.
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.
These include contracts with contract research organizations, or CROs, clinical manufacturing organizations, or CMOs, testing laboratories, research hospitals and not-for-profit organizations and other entities to support our research and development activities. We expense the cost of each contract as the work is performed.
Research and Development and Pharmaceutical Drug Manufacturing Accruals We have entered into various contracts with third parties to perform research and development and pharmaceutical drug manufacturing. These include contracts with contract research organizations, or CROs, clinical manufacturing organizations, or CMOs, testing laboratories, research hospitals and not-for-profit organizations and other entities to support our research and development activities.
The liability related to the sale of future royalties and the related interest expense are based on our current estimates of future royalties, which we determine by using third-party forecasts of MAVYRET/MAVIRET sales. Third-party forecasts are updated periodically based on the latest pricing, market share, and patient data.
Interest expense for the liability related to the sale of future royalties will be recognized using the effective interest rate method over the term of the royalty sale agreement. 63 The liability related to the sale of future royalties and the related interest expense are based on our current estimates of future royalties, which we determine by using third-party forecasts of MAVYRET/MAVIRET sales.
Changes in the amount or timing of estimated royalties will affect the interest rate utilized in calculating the liability related to the sale of future royalties.
Third-party forecasts are updated periodically based on the latest pricing, market share, and patient data. Changes in the amount or timing of estimated royalties will affect the interest rate utilized in calculating the liability related to the sale of future royalties.
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.
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.
Immunology 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.
We also have clinical stage programs in virology for SARS-CoV-2, the virus that causes COVID-19, and Hepatitis B virus, or HBV, the most prevalent chronic hepatitis. Immunology In immunology, we are designing and developing highly potent and selective oral small molecule inhibitors for the treatment of type 2 inflammatory disease by targeting key mechanisms of the immune response.
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.
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.
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. 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.
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.
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. 67 Income tax benefit (expense) 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 decrease was due to lower cash and investment balances year over year. 65 Income tax benefit (expense) During each of the years ended September 30, 2025 and 2024, we recorded an income tax benefit of $1.7 million, representing interest recorded on our $33.8 million federal tax refund, which we received in April 2025.
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. 63 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.
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.
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.
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.
Revenue Our revenue is primarily derived from our collaboration agreement with AbbVie and AbbVie’s sales of MAVYRET/MAVIRET, an 8-week treatment regimen for 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.
Revenue Our revenue is primarily derived from our collaboration agreement with AbbVie and AbbVie’s sales of MAVYRET/MAVIRET, an 8-week treatment regimen for acute or chronic HCV.
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.
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.
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.
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.
Costs associated with HBV decreased as we continued to wind down this program pending our identification of a potential partnering compound for EDP-514. Immunology The costs in our immunology programs increased by $24.5 million as this is a new therapeutic area of focus for the company.
Virology The costs in our virology program decreased by $30.8 million primarily due to the timing of clinical trials in our RSV programs. Immunology The costs in our immunology programs increased by $10.2 million as we advance this new therapeutic area of focus for the company.
Our research and drug discovery and development programs are in early stages; therefore, the successful development of our product candidates is highly uncertain and may not result in approved products. Completion dates and completion costs can vary significantly for each product candidate and are difficult to predict.
Completion dates and completion costs can vary significantly for each product candidate and are difficult to predict.
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We also have development programs in virology for the following disease targets: • SARS-CoV-2, the virus that causes COVID-19, with estimates suggesting that COVID-19 continues to have a disease burden greater than influenza, including persistent cases of infection often referred to as long COVID and hospitalization and death among the elderly and those with comorbidities, while new variants continue to emerge on a regular basis; and • Hepatitis B virus, or HBV, the most prevalent chronic hepatitis, which is estimated by the World Health Organization to affect close to 300 million individuals worldwide.
Added
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.
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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.
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An overactive response is a primary driver of a number of inflammatory diseases.
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Our Wholly-Owned Programs Our primary wholly-owned research and development programs are in virology and immunology. RSV . In virology, we have two clinical stage product candidates for RSV – zelicapavir (formerly EDP-938) and EDP-323.
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As of September 30, 2025, we had $188.9 million in cash, cash equivalents and short-term marketable securities.
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Both of these compounds are replication inhibitors that work by shutting down replication and the production of new virions, as opposed to the other mechanism in development of fusion inhibition that only blocks viral entry. Zelicapavir, which has Fast Track designation from the U.S.
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The annual royalty tiers return to the lowest tier for sales on and after each January 1.
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Food and Drug Administration, or FDA, is a potent inhibitor of the RSV N-protein for both major subgroups of RSV, referred to as RSV-A and RSV-B. Zelicapavir is being studied in two Phase 2 studies, each in a different high risk patient population.
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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.
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EDP-323, which also has a Fast Track designation from the FDA is an inhibitor of the RSV L-protein for both major subgroups of RSV that has recently completed a Phase 2 challenge study. • Zelicapavir - N-protein Inhibitor Candidate: We have studied zelicapavir in two Phase 2 studies that were designed to be proof-of-concept and exploratory studies in otherwise healthy young adults (not at high-risk for serious outcomes with RSV) to understand the viral response in the context of RSV infection.
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On July 4, 2025, the U.S. government enacted the One Big Beautiful Bill Act ("OBBBA"), which includes several changes to U.S. federal income tax law, including the temporary and permanent extension of expiring provisions of the Tax Cuts and Jobs Act of 2017.
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With these studies, zelicapavir has demonstrated a favorable safety profile, consistent with that observed in over 500 subjects exposed to zelicapavir to date.
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We determined that the tax provisions of the legislation do not have a material impact on our 2025 consolidated financial statements and continue to assess the impact on future years. Critical Accounting Policies Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America.
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We believe that zelicapavir has the greatest potential to show optimal efficacy in high-risk populations since these patients have reduced RSV immunity, which manifests in a higher and longer duration of viral load and greater disease severity, allowing a bigger window to realize the full potential of zelicapavir.
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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.
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Based on its growing safety profile, we are continuing to evaluate zelicapavir in high-risk populations, including pediatric patients and high-risk adults, all of which have significant unmet need: o Pediatric Study of Zelicapavir : RSVPEDs is a Phase 2 study of zelicapavir in 96 pediatric patients, aged >28 days to o High-Risk Adults Study of Zelicapavir : We also have an ongoing Phase 2b study in high-risk adults, including those who are older than 65 years of age and those who have asthma, chronic obstructive pulmonary disease, or COPD, or congestive heart failure.
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Other Programs Other program costs decreased by $4.1 million due to the completion of the discovery-stage activities related to our STAT6 program.
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Approximately 180 patients will be treated with zelicapavir or placebo for five days with a primary endpoint of time to resolution of RSV lower respiratory tract disease symptoms.
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On July 4, 2025, the U.S. government enacted the One Big Beautiful Bill Act ("OBBBA"), which includes several changes to U.S. federal income tax law, including the temporary and permanent extension of expiring provisions of the Tax Cuts and Jobs Act of 2017.
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Enrollment is progressing and we are targeting enrollment completion in the current Northern Hemisphere RSV season with topline data expected in 2025. • EDP-323 - L-protein Inhibitor Candidate: Our second clinical RSV candidate, EDP-323, is a novel oral, direct-acting antiviral selectively targeting the RSV L-protein, a viral RNA-dependent RNA polymerase enzyme that contains multiple enzymatic activities required for RSV replication.
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We determined that the tax provisions of the legislation do not have a material impact on our 2025 consolidated financial statements and continue to assess the impact on future years.
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EDP-323 has sub-nanomolar potency against RSV-A and RSV-B in vitro and protected mice in a dose-dependent manner from RSV infection as demonstrated by both virological and pathological endpoints.
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EDP-323 is not expected to have cross-resistance to other classes of inhibitors and has the potential to be used alone, or in combination with other RSV mechanisms, to broaden the treatment window or addressable patient populations. In September 2024, we announced positive topline results for EDP-323 in a Phase 2a challenge study of healthy adults infected with RSV.
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Treatment with EDP-323 achieved highly statistically significant (p= COVID-19 . We leveraged our expertise in developing protease inhibitors to discover compounds specifically designed to target the SARS-CoV-2 virus and potentially other coronaviruses. We selected EDP-235, an oral inhibitor of the coronavirus 3CL protease, also referred to as 3CLpro or the main coronavirus protease, or Mpro, for clinical development.
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In addition to nanomolar activity against all SARS-CoV-2 variants tested to date, EDP-235 has potent antiviral activity against other human coronaviruses, enabling the potential for a pan-coronavirus treatment, including possibly coronaviruses that may infect human populations in the future.
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Furthermore, EDP-235 has good tissue distribution, and is projected to have four times higher drug levels in lung tissue compared to plasma. 61 • SPRINT Study of EDP-235: In May 2023, we reported topline results from a Phase 2 clinical trial of EDP-235 in non-hospitalized, symptomatic patients with mild to moderate COVID-19 who were not at increased risk for developing severe disease, which was the only study population permitted by the FDA.

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Item 7A. Quantitative and Qualitative Disclosures About Market Risk

Market Risk — interest-rate, FX, commodity exposure

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Biggest changeITEM 7A. QUANTITATIVE AND QUALITAT IVE DISCLOSURES ABOUT MARKET RISK Interest Rate Risk We had cash, cash equivalents and short-term marketable securities of $248.2 million and $369.9 million at September 30, 2024 and 2023, respectively, which consisted of cash, money market funds, corporate bonds, commercial paper and treasury notes.
Biggest changeITEM 7A. QUANTITATIVE AND QUALITAT IVE DISCLOSURES ABOUT MARKET RISK Interest Rate Risk We had cash, cash equivalents and short-term marketable securities of $188.9 million and $248.2 million at September 30, 2025 and 2024, respectively, which consisted of cash, money market funds, and treasury notes.
During fiscal 2024 and 2023, the impact of foreign currency exposure was immaterial and thus did not have a significant impact on our consolidated financial statements. Our operations may become subject to more significant fluctuations in foreign currency exchange rates in the future if we continue to contract with vendors outside of the U.S. ITEM 8.
During fiscal 2025 and 2024, the impact of foreign currency exposure was immaterial and thus did not have a significant impact on our consolidated financial statements. Our operations may become subject to more significant fluctuations in foreign currency exchange rates in the future if we continue to contract with vendors outside of the U.S. ITEM 8.
CONSOLIDATED FINANCIAL STATEMEN TS AND SUPPLEMENTARY DATA Our consolidated financial statements, together with the report of our independent registered public accounting firm, appear on pages F-1 through F-25 of this Annual Report on Form 10-K. 70
CONSOLIDATED FINANCIAL STATEMEN TS AND SUPPLEMENTARY DATA Our consolidated financial statements, together with the report of our independent registered public accounting firm, appear on pages F-1 through F-26 of this Annual Report on Form 10-K. 68

Other ENTA 10-K year-over-year comparisons