Atea Pharmaceuticals' investigational once-daily combination of bemnifosbuvir and ruzasvir (BEM/RZR) met its primary end point of statistical noninferiority to sofosbuvir/velpatasvir (SOF/VEL; Epclusa) in the phase 3 C-BEYOND trial, the company's first successful head-to-head study in a global phase 3 hepatitis C virus (HCV) program.1 The trial, conducted at approximately 120 sites in the US and Canada, enrolled 905 patients in the modified intent-to-treat (mITT) population.1,2
In the mITT analysis, BEM/RZR achieved a 93.9% sustained virologic response (SVR) rate at week 24 compared with 94.8% for SOF/VEL, with the 95% CI for the difference in SVR rates falling within the prespecified 5-percentage-point margin. Noninferiority was also met on secondary end points, including the per-protocol analysis.1
"We are pleased to announce these positive results from C-BEYOND showing our regimen of BEM/RZR achieved high cure rates across all populations and genotypes," Jean-Pierre Sommadossi, PhD, founder and chief executive officer of Atea Pharmaceuticals, said in a statement.1 Sommadossi said the results, announced on World Hepatitis Day, underscore the complexity of HCV as a public health challenge and said the company believes BEM/RZR's profile will contribute meaningfully to the World Health Organization's goal of HCV eradication.1
C-BEYOND trial shows noninferiority to sofosbuvir/velpatasvir with as little as 8 weeks of treatment
What Infectious Disease Specialists Need to Know
What were the primary results of the C-BEYOND trial?
BEM/RZR achieved a 93.9% sustained virologic response rate at week 24 compared with 94.8% for sofosbuvir/velpatasvir, meeting the trial's prespecified noninferiority margin.
How does the treatment duration compare with the current standard of care?
Patients without cirrhosis received BEM/RZR for 8 weeks compared with 12 weeks of sofosbuvir/velpatasvir, while both regimens were given for 12 weeks in patients with cirrhosis.
What is the safety profile of BEM/RZR?
BEM/RZR was generally safe and well tolerated in C-BEYOND, with no drug-related serious adverse events or drug-related early treatment discontinuations reported.
Among patients without cirrhosis (n = 721), BEM/RZR given for 8 weeks achieved a 93.5% SVR rate compared with 94.6% for SOF/VEL given for 12 weeks.1 Among patients with cirrhosis, n = 184, both regimens were given for 12 weeks and each achieved a 95.4% SVR rate.1 Rates of virologic failure were low and comparable between treatment arms across all populations, and BEM/RZR was generally safe and well tolerated with no drug-related serious adverse events (AEs) or drug-related early treatment discontinuations reported.1
Approximately 80% to 90% of people with HCV in the United States do not have cirrhosis, the population in which BEM/RZR's shortened 8-week course was evaluated.1 The phase 3 results build on earlier phase 2 lead-in cohort data for the same combination, which showed a 97% SVR12 rate, including in patients with genotype 3 infection, a historically difficult-to-treat genotype.1 Bemnifosbuvir is a nucleotide analog polymerase inhibitor shown in vitro to be approximately 10-fold more active than sofosbuvir against a panel of HCV genotype 1 through 5 strains, and ruzasvir is an NS5A inhibitor with pan-genotypic antiviral activity in preclinical and clinical studies.1
Regimen Positioned as Best-in-Class Option Amid Ongoing Elimination Efforts
"Achieving these high cure rates with just 8 weeks of BEM/RZR in patients without cirrhosis, alongside a favorable drug-drug interaction profile and the flexibility to be taken with or without food, is a meaningful step forward for HCV care," said Eric Lawitz, MD, clinical professor of medicine at UT Health San Antonio and the Texas Liver Institute.1 Lawitz said many of his patients manage multiple chronic conditions and take several concomitant medications, making a regimen with a low risk of drug interactions and consistent dosing regardless of food intake especially useful in practice.
An estimated 50 million people worldwide are living with HCV, including up to 4 million people in the United States, and new diagnoses continue to outpace annual cures, a burden that falls unevenly across populations, including immigrants from high-prevalence countries.1 Left untreated, chronic HCV infection can progress to cirrhosis, end-stage liver disease, and liver cancer, and it remains a leading cause of liver cancer in the US, Europe, and Japan.1 Atea's second phase 3 trial of BEM/RZR outside North America, C-FORWARD, has enrolled more than 880 patients across 17 countries and is expected to report topline results in early 2027.1
References
Atea Pharmaceuticals, Inc. Atea Pharmaceuticals Meets Both Its Primary and Secondary Endpoints in the Phase 3 C-BEYOND North America Trial Evaluating Bemnifosbuvir/Ruzasvir for Hepatitis C Virus. News release. Published July 28, 2026. Accessed July 30, 2026. https://www.biospace.com/press-releases/atea-pharmaceuticals-meets-both-its-primary-and-secondary-endpoints-in-the-phase-3-c-beyond-north-america-trial-evaluating-bemnifosbuvir-ruzasvir-for-hepatitis-c-virus
ClinicalTrials.gov. A Study of Bemnifosbuvir and Ruzasvir Fixed-Dose Combination Compared With Sofosbuvir and Velpatasvir Fixed-Dose Combination in Adults With Chronic Hepatitis C Virus Infection (C-BEYOND). NCT06868264. Accessed July 30, 2026. https://clinicaltrials.gov/study/NCT06868264
