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

October 6, 2025 updated by: Atea Pharmaceuticals, Inc.

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

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
275

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

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

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Percentage of Subjects Achieving Sustained Virologic Response at 12 Weeks Post-treatment (SVR12)
Time Frame: Day 1 through 12 weeks after end of treatment
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Percentage of Subjects Experiencing Virologic Failure
Time Frame: Day 1 through 12 weeks after end of treatment
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)
Time Frame: Day 1 through 24 weeks after end of treatment
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

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Atea Pharmaceuticals, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 30, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 9, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 28, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 6, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 6, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 15, 2023

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 21, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 6, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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