A Phase 2, Safety and Efficacy of Bemnifosbuvir (BEM) and Ruzasvir (RZR) in Subjects With Chronic HCV

A Phase 2, Open-label Study to Assess the Safety and Efficacy of Bemnifosbuvir (BEM) and Ruzasvir (RZR) in Subjects With Chronic Hepatitis C Virus (HCV) Infection

This is an open-label trial to evaluate safety and efficacy of treatment with BEM + RZR in subjects with chronic HCV infection.

Study Overview

• Status: Completed
• Conditions: Hepatitis C; Hepatitis C, Chronic; HCV; Chronic Hepatitis C Virus; Hepatic Cirrhosis
• Intervention / Treatment: Drug: Bemnifosbuvir; Drug: Ruzasvir

• Study Type: Interventional
• Enrollment (Actual): 275
• Phase: Phase 2

Contacts and Locations

Study Locations

• Brazil
  • Amazonas
    • Manaus, Amazonas, Brazil, 69040-000
      • Atea Study Site
  • Estado de Bahia
    • Salvador, Estado de Bahia, Brazil, 41920-900
      • Atea Study Site
  • Federal District
    • Brasília, Federal District, Brazil, 70200-730
      • Atea Study Site
  • Rio Do Janeiro
    • Rio de Janeiro, Rio Do Janeiro, Brazil, 04037-030
      • Atea Study Site
  • Rio Grande do Sul
    • Porto Alegre, Rio Grande do Sul, Brazil, 90035-074
      • Atea Study Site
    • Porto Alegre, Rio Grande do Sul, Brazil, 90035-903
      • Atea Study Site
  • Rondônia
    • Porto Velho, Rondônia, Brazil, 78918-791
      • Atea Study Site
  • Roraima
    • Boa Vista, Roraima, Brazil, 69304-015
      • Atea Study Site
  • São Paulo
    • Botucatu, São Paulo, Brazil, 18618-970
      • Atea Study Site
    • Ijuí, São Paulo, Brazil, 98700-000
      • Atea Study Site
    • Sorocaba, São Paulo, Brazil, 18052-210
      • Atea Study Site
    • São José do Rio Preto, São Paulo, Brazil, 15090-000
      • Atea Study Site
    • São Paulo, São Paulo, Brazil, 04119-001
      • Atea Study Site
    • São Paulo, São Paulo, Brazil, 05403-000
      • Atea Study Site
• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V6Z 2C7
      • Atea Study Site
  • Ontario
    • Toronto, Ontario, Canada, M5G 2C4
      • Atea Study Site
• India
  • Gujarat
    • Rajkot, Gujarat, India, 360005
      • Atea Study Site
    • Surat, Gujarat, India, 395002
      • Atea Study Site
  • Karnataka
    • Belagavi, Karnataka, India, 590010
      • Atea Study Site
  • Maharashtra
    • Nagpur, Maharashtra, India, 440010
      • Atea Study Site
  • West Bengal
    • Kolkata, West Bengal, India, 700020
      • Atea Study Site
• Mauritius
  • Quatre Bornes, Mauritius, 72218
    • Atea Study Site
• Moldova
  • Chisinau, Moldova, 2025
    • Atea Study Site
• Pakistan
  • Karachi, Pakistan, 74800
    • Atea Study Site
  • Karachi, Pakistan, 75600
    • Atea Study Site
• Philippines
  • Baguio City, Philippines, 35100
    • Atea Study Site
  • Iloilo City, Philippines, 5000
    • Atea Study Site
  • Mabalacat, Philippines, 2023
    • Atea Study Site
• Romania
  • Bucharest, Romania, 21105
    • Atea Study Site
  • BUC
    • Bucharest, BUC, Romania, 022328
      • Atea Study Site
    • Bucharest, BUC, Romania, 30303
      • Atea Study Site
  • CON
    • Constanța, CON, Romania, 900709
      • Atea Study Site
  • DOL
    • Craiova, DOL, Romania, 200073
      • Atea Study Site
• South Africa
  • Free State
    • Bloemfontein, Free State, South Africa, 9301
      • Atea Study Site
  • Gauteng
    • Johannesburg, Gauteng, South Africa, 2193
      • Atea Study Site
    • Randburg, Gauteng, South Africa, 2087
      • Atea Study Site
  • Western Cap
    • Somerset West, Western Cap, South Africa, 7130
      • Atea Study Site
• South Korea
  • Busan, South Korea, 47392
    • Atea Study Site
  • Busan, South Korea, 49241
    • Atea Study Site
  • Seoul, South Korea, 5505
    • Atea Study Site
  • Seoul, South Korea, 6351
    • Atea Study Site
  • Gyeonggi-do
    • Seoul, Gyeonggi-do, South Korea, 120-752
      • Atea Study Site
  • Gyeongsangnam
    • Yangsan, Gyeongsangnam, South Korea, 626-770
      • Atea Study Site
• Turkey (Türkiye)
  • Adana, Turkey (Türkiye), 1130
    • Atea Study Site
  • Ankara, Turkey (Türkiye), 6100
    • Atea Study Site
  • Ankara, Turkey (Türkiye), 6230
    • Atea Study Site
  • Ankara, Turkey (Türkiye), 6800
    • Atea Study Site
  • Denizli, Turkey (Türkiye), 20070
    • Atea Study Site
  • Izmir, Turkey (Türkiye), 35100
    • Atea Study Site
  • Kayseri, Turkey (Türkiye), 38010
    • Atea Study Site
• United States
  • Texas
    • San Antonio, Texas, United States, 78215
      • Atea Study Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Willing and able to provide written informed consent
• Male or female subjects between ≥ 18 years of age (or the legal age of consent per local regulations) and ≤ 85 years of age
• Female subjects of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or to the use of an acceptable effective contraception
• Females must have a negative pregnancy test at Screening and at Day 1 prior to dosing
• Subjects must be direct-acting antiviral (DAA)-treatment-naïve, defined as never exposed to an approved or experimental DAA for HCV
• Documented medical history compatible with chronic HCV

• Liver disease staging assessment as follows:

  • Absence of cirrhosis (F0 to F3)
  • Compensated cirrhosis (F4)

Exclusion Criteria:

• Female subject is pregnant or breastfeeding
• Co-infected with hepatitis B virus (HBV; positive for hepatitis B surface antigen [HBsAg]) and/or human immunodeficiency virus (HIV)
• Abuse of alcohol and/or illicit drug use that could interfere with adherence to study requirements as judged by the investigator
• Prior exposure to any HCV DAA
• Use of other investigational drugs within 30 days of dosing or plans to enroll in another clinical trial of an investigational agent while participating in the present study
• Subject with known allergy to the study medications or any of their components
• History or signs of decompensated liver disease: ascites, variceal bleeding, hepatic encephalopathy, spontaneous bacterial peritonitis, or other clinical signs of portal hypertension or hepatic insufficiency
• Cirrhotic and has a Child-Pugh score >6, corresponding to a Child-Pugh Class B or C
• History of hepatocellular carcinoma (HCC) or findings suggestive of possible HCC
• Any other clinically significant medical condition that, in the opinion of the investigator, would jeopardize the safety of the subject or impact the validity of the study results

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bemnifosbuvir and Ruzasvir; Bemnifosbuvir (BEM; AT-527) Tablets Ruzasvir (RZR; AT-038) Capsules	Drug: Bemnifosbuvir; 550 mg administered orally once a day (QD) for 8 weeks; Other Names: AT-527; Drug: Ruzasvir; 180 mg administered orally once a day (QD) for 8 weeks; Other Names: AT-038

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Subjects Achieving Sustained Virologic Response at 12 Weeks Post-treatment (SVR12)	SVR12 defined as plasma hepatitis C virus (HCV) RNA less than the lower limit of quantitation (<LLOQ) at 12 weeks post-treatment	Day 1 through 12 weeks after end of treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Subjects Experiencing Virologic Failure	Virologic failure defined as a confirmed 1 log10 increase in HCV RNA from post-baseline nadir, or confirmed increase in HCV RNA ≥ LLOQ in any subject who achieved HCV RNA < LLOQ.	Day 1 through 12 weeks after end of treatment
Percentage of Subjects Achieving Sustained Virologic Response at 24 Weeks Post-treatment (SVR24)	SVR24 defined as plasma HCV RNA less than the lower limit of quantitation (<LLOQ) at 24 weeks post-treatment	Day 1 through 24 weeks after end of treatment

Collaborators and Investigators

• Sponsor: Atea Pharmaceuticals, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): May 30, 2023
• Primary Completion (Actual): December 9, 2024
• Study Completion (Actual): January 28, 2025

Study Registration Dates

• First Submitted: June 6, 2023
• First Submitted That Met QC Criteria: June 6, 2023
• First Posted (Actual): June 15, 2023

Study Record Updates

• Last Update Posted (Estimated): October 21, 2025
• Last Update Submitted That Met QC Criteria: October 6, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Blood-Borne Infections; Pathologic Processes; Chronic Disease; Disease Attributes; Infections; RNA Virus Infections; Virus Diseases; Digestive System Diseases; Liver Diseases; Hepatitis, Viral, Human; Communicable Diseases; Flaviviridae Infections; Fibrosis; Hepatitis, Chronic; Hepatitis; Pathological Conditions, Signs and Symptoms; Liver Cirrhosis; Hepatitis C; Hepatitis C, Chronic; Anti-Infective Agents; Antiviral Agents; AT-511; ruzasvir
• Other Study ID Numbers: AT-01B-004

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes