Atea Pharmaceuticals to Present New Data Supporting Combination of Bemnifosbuvir and Ruzasvir as Potential Best-in-Class Regimen for Treatment of Hepatitis C Virus Infection at The Liver Meeting® 2025

Rhea-AI Summary

Atea Pharmaceuticals (Nasdaq: AVIR) will present new data at The Liver Meeting® 2025 (Nov 7-11, Washington, DC) supporting the combination regimen of bemnifosbuvir and ruzasvir for hepatitis C. Three accepted abstracts cover multiscale Phase 2 modeling, a viral resistance analysis, and a Phase 1 food-effect/bioavailability study for a fixed-dose combination. Prior Phase 2 results (n=275) showed SVR12 98% in the per-protocol treatment-adherent population and 95% in the efficacy-evaluable population. A virtual KOL investor event is scheduled for Nov 13, 2025 at 10:00 AM ET.

Positive

• SVR12 98% in per-protocol treatment-adherent population
• SVR12 95% in efficacy-evaluable (includes 17% non-adherent)
• Phase 1 data show high relative bioavailability for fixed-dose combo
• Phase 1 studies indicate low risk of drug-drug interactions

Negative

• 17% non-adherence in Phase 2 reduced the evaluable SVR12 rate
• Phase 3 global program ongoing with no pivotal results yet

BOSTON, Oct. 07, 2025 (GLOBE NEWSWIRE) -- Atea Pharmaceuticals, Inc. (Nasdaq: AVIR) (Atea or Company), a clinical-stage biopharmaceutical company engaged in the discovery and development of oral antiviral therapeutics for serious viral diseases, today announced that new data will be presented supporting the combination regimen of bemnifosbuvir, a nucleotide analog polymerase inhibitor and ruzasvir, an NS5A inhibitor, as a potential best-in-class regimen for the treatment of hepatitis C (HCV) infection at The Liver Meeting^® 2025, the annual meeting of the American Association for the Study of Liver Diseases (AASLD). Accepted for presentations were three abstracts detailing multi-scale HCV modeling results and a viral resistance analysis both from the Phase 2 study evaluating the combination regimen of bemnifosbuvir and ruzasvir and results from a Phase 1 study investigating whether there is a food effect with the fixed-dose combination of bemnifosbuvir and ruzasvir. The Liver Meeting 2025 will take place November 7-11 in Washington, DC.

“As we continue to advance our efforts to develop a best-in-class regimen with an optimized profile for all individuals living with hepatitis C, as well as the providers who care for them, we look forward to presenting at The Liver Meeting 2025 these new results supporting our regimen,” said Jean-Pierre Sommadossi, PhD, Chief Executive Officer and Founder of Atea Pharmaceuticals. “With patient enrollment in our global Phase 3 program well under way, we are excited about the potential that the regimen of bemnifosbuvir and ruzasvir has to reshape the standard of care for HCV and increase the number of patients who are successfully treated and cured.”

The accepted abstracts will become available on the AASLD website following the embargo lift on Tuesday, October 7^th at 8:00 AM Eastern Time (ET). Details of the presentations are as follows:

Oral Presentation

Abstract Number: 0089
Title: Multiscale Modeling of Results from a Phase 2 Study of an 8-week Combination Regimen of Bemnifosbuvir and Ruzasvir in Patients with Chronic Hepatitis C Virus Infection
Presenting Author: Carolin Zitzmann, PhD
Date and Time: Monday, November 10^th, 11:30 AM – 11:45 AM ET

Poster Presentations

Abstract Number: 1381
Identified as a Poster of Distinction
Title No Impact of RASs on the High Efficacy of BEM and RZR in Combination: Resistance Analysis from a Phase 2 Study in HCV-Infected Patients
Presenting Author: Qi Huang, PhD
Date and Time: Friday, November 7^th, 8:00 AM – 5:00 PM ET

Abstract Number: 1398
Title: Bemnifosbuvir and Ruzasvir Provided as a Fixed-dose Combination Demonstrates High Relative Bioavailability to Their Individual Formulations and Can Be Dosed with No Regard to Food
Presenting Author: Xiao-Jian Zhou, PhD
Date and Time: Friday, November 7^th, 8:00 AM – 5:00 PM ET

Earlier this year, at the European Association for the Study of the Liver (EASL) Congress 2025, Atea presented results from the full cohort of patients (n=275) enrolled in its Phase 2 study evaluating the regimen. These results showed a robust 98% (210/215) SVR12 with the regimen in the “Per-Protocol Treatment-Adherent Population.” The SVR12 rate was 95% (245/259) in the “Per-Protocol Regardless of Adherence Population” (also referred to as the “efficacy evaluable population”), which included patients who were not treatment adherent (17%).

Results from three Phase 1 studies presented at the EASL Congress 2025 demonstrated that the combination of bemnifosbuvir and ruzasvir had a low risk of drug-drug interactions (DDIs) and supported the safety of the regimen in HCV patients co-infected with human immunodeficiency virus (HIV) taking a standard HIV treatment, and the safety of bemnifosbuvir in participants with hepatic or renal impairment with no need for dose adjustments.

HCV KOL Investor Event at 10:00 AM ET on November 13, 2025

Following The Liver Meeting 2025, Atea will host a virtual key opinion leader (KOL) investor event with a panel of HCV clinical experts on Thursday, November 13 at 10:00 AM ET.

This event will include a panel of global leaders in hepatology and HCV research and treatment. These experts will discuss the current challenges patients and prescribers face in the diagnosis and treatment of HCV, strategies for advancing global elimination efforts and the benefits a next-generation treatment option with an optimized profile could provide for prescribers and patients.

Company management will discuss the HCV commercial market opportunity, provide an update on the ongoing global Phase 3 clinical development and review new data supporting the regimen of bemnifosbuvir and ruzasvir for the treatment of HCV.

About the Phase 3 C-BEYOND and C-FORWARD Trials in Adults with Chronic HCV

Atea’s HCV Phase 3 development program includes two open-label Phase 3 trials, C-BEYOND being conducted in the US and Canada, and C-FORWARD being conducted outside of North America. Each Phase 3 trial is enrolling approximately 880 treatment-naïve patients, including those with and without compensated cirrhosis. The trials compare the fixed-dose combination (FDC) regimen of bemnifosbuvir and ruzasvir to the FDC regimen of sofosbuvir and velpatasvir. The regimen of bemnifosbuvir and ruzasvir is administered orally once-daily for eight weeks (in patients without cirrhosis) or 12 weeks (in patients with compensated cirrhosis) while the regimen of sofosbuvir and velpatasvir is administered orally once-daily for 12 weeks to all patients, with or without compensated cirrhosis.

The primary endpoint for each trial is HCV RNA < lower limit of quantitation (LLOQ) at 24 weeks from the start of treatment and encompasses sustained virologic response 12 weeks post-treatment (SVR12) in each arm. Measurement at 24 weeks from the start of treatment is to ensure the primary endpoint occurs at the same relative timepoint from the start of treatment in all patients.

About Hepatitis C Virus (HCV)

HCV is a blood-borne, positive-sense, single-stranded (ss) RNA virus that primarily infects liver cells. HCV is a leading cause of chronic liver disease and liver transplants, spreading via blood transfusion, hemodialysis and needle sticks, with approximately 240,000 deaths occurring each year. Despite the availability of direct-acting antivirals, HCV continues to be a significant global healthcare issue. An estimated 50 million people worldwide are chronically infected with HCV and there are approximately one million new infections each year. In the US, between 2.4 and 4 million people are estimated to have HCV with annual new infections outpacing treatment rates. HCV infections in the US predominate in patients in the age group between 20-49 years old, and it is estimated that less than 10% of HCV-infected patients in the US have cirrhosis. Chronic HCV infection is the leading cause of liver cancer in the US, Europe and Japan.

About Bemnifosbuvir and Ruzasvir for HCV

Bemnifosbuvir has been shown in in vitro studies to be approximately 10-fold more active than sofosbuvir (SOF) against a panel of laboratory strains and clinical isolates of HCV GT 1–5. In vitro studies have also demonstrated bemnifosbuvir remained fully active against SOF resistance-associated substitutions (S282T), with up to 58-fold more potency than SOF. The pharmacokinetic (PK) profile of bemnifosbuvir supports once-daily dosing for the treatment of HCV. In both nonclinical and clinical studies, bemnifosbuvir has been shown to have a low risk for DDIs. Bemnifosbuvir has been administered to over 2,300 subjects and has been well-tolerated at doses up to 550 mg for durations up to 12 weeks in healthy subjects and patients.
Ruzasvir has demonstrated highly potent and pan-genotypic antiviral activity in preclinical (picomolar range) and clinical studies. Ruzasvir has been administered to over 2,100 subjects at daily doses of up to 180 mg for 12 weeks and has demonstrated a favorable safety profile. The PK profile of ruzasvir supports once-daily dosing.

About Atea Pharmaceuticals

Atea is a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing oral antiviral therapies to address the unmet medical needs of patients with serious viral infections. Leveraging Atea’s deep understanding of antiviral drug development, nucleos(t)ide chemistry, biology, biochemistry and virology, Atea has built a proprietary nucleos(t)ide prodrug platform to develop novel product candidates to treat single stranded ribonucleic acid, or ssRNA, viruses, which are a prevalent cause of serious viral diseases. Atea plans to continue to build its pipeline of antiviral product candidates by augmenting its nucleos(t)ide platform with other classes of antivirals that may be used in combination with its nucleos(t)ide product candidates. Atea’s lead program is the regimen of bemnifosbuvir, a nucleotide analog polymerase inhibitor, and ruzasvir, an NS5A inhibitor, to treat HCV. For more information, please visit www.ateapharma.com.

Forward-Looking Statements

This press release includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements in this press release include but are not limited to statements regarding the development of the regimen of bemnifosbuvir and ruzasvir for the treatment of HCV and the potential best in class profile of the regimen and the ability of the regimen, if approved, to help improve patient outcomes and to provide opportunities to expand the number of patients treated and cured. When used herein, words including “expected,” “should,” “anticipated,” “believe,” “will,” “plans,” and similar expressions are intended to identify forward-looking statements. In addition, any statements or information that refer to expectations, beliefs, plans, projections, objectives, performance or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking. All forward-looking statements are based upon Atea’s current expectations and various assumptions. Atea believes there is a reasonable basis for its expectations and beliefs, but they are inherently uncertain. Atea may not realize its expectations, and its beliefs may not prove correct. Actual results could differ materially from those described or implied by such forward-looking statements as a result of various important factors, including, without limitation. Atea’s dependence on the success of its most advanced product candidate the regimen of bemnifosbuvir and ruzasvir for the treatment of HCV; as well as the other important factors discussed under the caption “Risk Factors” in Atea’s Annual Report on Form 10-K for the year ended December 31, 2024 as such factors may be updated from time to time in its other filings with the SEC, which are accessible on the SEC’s website at www.sec.gov. These and other important factors could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s estimates as of the date of this press release. While Atea may elect to update such forward-looking statements at some point in the future, except as required by law, it disclaims any obligation to do so, even if subsequent events cause our views to change. These forward-looking statements should not be relied upon as representing Atea’s views as of any date subsequent to the date of this press release.

Contacts

Jonae Barnes
SVP, Investor Relations and Corporate Communications
617-818-2985
barnes.jonae@ateapharma.com

Joyce Allaire
LifeSci Advisors
Jallaire@lifesciadvisors.com

FAQ

What Phase 2 SVR12 rates did Atea report for bemnifosbuvir+ruzasvir (AVIR)?

Phase 2 showed SVR12 98% in the per-protocol treatment-adherent group and 95% in the efficacy-evaluable group.

When and where will Atea present AVIR bemnifosbuvir+ruzasvir data at The Liver Meeting 2025?

Presentations occur during The Liver Meeting Nov 7-11, 2025 in Washington, DC, with an oral talk on Nov 10 and posters on Nov 7.

Does the fixed-dose bemnifosbuvir+ruzasvir formulation require dosing with food (AVIR)?

Phase 1 data presented indicate the fixed-dose combination has high relative bioavailability and can be dosed with no regard to food.

Will Atea discuss commercial and clinical plans for AVIR after The Liver Meeting 2025?

Yes. Atea will host a virtual KOL investor event on Nov 13, 2025 at 10:00 AM ET to review Phase 3 updates and commercial opportunity.

Do the Phase 1 results for AVIR suggest drug-drug interaction risks with HIV therapy?

Phase 1 studies reported a low risk of drug-drug interactions and supported safety with standard HIV treatment.