BOSTON, November 7, 2025 — Leads & Copy — Atea Pharmaceuticals, Inc. (Nasdaq: AVIR) announced new modeling data predicting that the company’s combination regimen of bemnifosbuvir (BEM) and ruzasvir (RZR) achieved near-complete inhibition of both viral replication and assembly and secretion into the bloodstream, with a modeled time to cure of approximately 7 to 8 weeks.
These findings support the fixed-dose combination (FDC) regimen of BEM and RZR as a potential best-in-class, convenient, short-duration treatment of hepatitis C virus (HCV), further validating the company’s Phase 2 study results, which demonstrated that the combination regimen, after 8 weeks of treatment, achieved sustained virologic response rates at 12 weeks post-treatment (SVR12) of 98% in the per-protocol treatment-adherent patient population and 95% in patients regardless of adherence.
These modeling data will be presented at The Liver Meeting® 2025, the annual meeting of the American Association for the Study of Liver Diseases (AASLD), taking place November 7-11 in Washington, DC.
The company will also present two additional datasets: 1) a resistance analysis from the same Phase 2 study supporting the regimen’s high barrier to resistance and 2) results from a Phase 1 study in healthy participants demonstrating the high relative bioavailability of the BEM/RZR FDC commercial formulation.
These data also support dosing of the FDC with or without food or with famotidine (an H2 blocker which can substantially diminish the effectiveness of HCV oral antivirals). The FDC commercial formulation is being used in the ongoing Phase 3 program.
All results being presented underscore the regimen’s potential best-in-class profile to address the needs of today’s broad population of HCV patients. This includes those patients taking concomitant medications, who may need the flexibility of a treatment option that can be taken with or without food, or who present with resistant strains of HCV or advanced liver disease.
Jean-Pierre Sommadossi, PhD, Chief Executive Officer and Founder of Atea Pharmaceuticals, said the company’s goal has always been to develop a best-in-class regimen for HCV that meaningfully advances the standard of care for as many people as possible by addressing the evolving needs of today’s HCV patients. He added that these new findings reinforce the differentiated profile of the company’s fixed-dose combination regimen of bemnifosbuvir and ruzasvir as a potent, pan-genotypic and convenient regimen with the potential to transform the treatment landscape and bring them closer to eradication of 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 or 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.
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 4.0 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.
Results from the Phase 2 study (n=275) evaluating the regimen of bemnifosbuvir and ruzasvir for 8 weeks showed a 98% SVR12 rate (210/215) 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 Phase 1 studies have demonstrated that the combination of bemnifosbuvir and ruzasvir has a low risk of drug-drug interactions (DDIs) and can be taken with or without food. Importantly, Phase 1 results showed no interaction between bemnifosbuvir and ruzasvir and a standard human immunodeficiency virus (HIV) treatment, supporting its potential use in HCV patients co-infected with HIV, and the safety of bemnifosbuvir in healthy volunteer participants with hepatic or renal impairment with no need for dose adjustments.
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. 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.
Contacts:
Jonae Barnes
SVP, Investor Relations and Corporate Communications
617-818-2985
barnes.jonae@ateapharma.com
Joyce Allaire
LifeSci Advisors
Jallaire@lifesciadvisors.com
Source: Atea Pharmaceuticals
