GS-4321 for healthy volunteers and people with chronic hepatitis delta

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

The trial is a Phase 1/2, first testing single ascending doses of GS-4321 in healthy adults to characterize safety, tolerability, and pharmacokinetics. In Phase 2, people with chronic hepatitis delta receive multiple escalating doses to measure safety and antiviral activity, with some participants randomized to placebo. Participants with HBV coinfection must remain on standard HBV antiviral therapy, and non‑decompensated liver disease is required for enrollment. Clinical and laboratory monitoring, including HDV RNA and liver tests, will be used to judge tolerability and antiviral effect across dose levels.

Why it matters

Who can join: the full rules

Key Inclusion Criteria:

Part A:

* Participants assigned male or female at birth who are of childbearing potential and engage in heterosexual intercourse must agree to use protocol-specified method(s) of contraception.
* Have a body mass index (BMI) of ≤ 30.0 kg/m2 at screening and at admission.

Part B:

* Participants assigned male or female at birth who are of childbearing potential and engage in heterosexual intercourse must agree to use protocol-specified method(s) of contraception.
* Chronic hepatitis delta (CHD) for ≥ 6 months prior to screening, documented by prior medical history.
* Must be receiving a commercially available entecavir, TAF, or TDF for the treatment of hepatitis B virus (HBV) infection at or prior to enrollment. Coformulation as part of a fixed-dose combination for the treatment of HIV is permitted.
* Non-cirrhotic or compensated cirrhosis.
* Hepatitis delta virus ribonucleic acid (HDV RNA ) \> 500 IU/mL at screening.
* Alanine aminotransferase (ALT) level \> 1 × Upper limit of normal (ULN), but \< 10 × ULN at screening.

Key Exclusion Criteria:

Part A:

* Positive serum or urine pregnancy test.
* Participants with plans to breastfeed during the study period.

Part B:

* Positive serum or urine pregnancy test.
* Participants with plans to breastfeed during the study period.
* Current or previous clinically decompensated liver disease, including coagulopathy, hepatic encephalopathy, and esophageal varices hemorrhage due to HDV or HBV.
* Child-Turcotte-Pugh (CTP)-B or -C or a CTP score of ≥ 7.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Where it's running

• Investigative Site
  Anaheim, California, United States Recruiting
• University of California, San Diego - Altman Clinical and Translational Research Institute
  La Jolla, California, United States Recruiting
• University of Louisville, Clinical Trials Unit
  Louisville, Kentucky, United States Recruiting
• University of Maryland, Institute of Human Virology, Clinical Research Unit
  Baltimore, Maryland, United States Recruiting
• The New York-Presbyterian Hospital
  New York, New York, United States Recruiting
• University Multi-profile Hospital for Active Treatment "SofiaMed" 00D
  Sofia, Bulgaria Recruiting

Study contacts

• Study coordinator: Gilead Clinical Study Information Center
• Email: GileadClinicalTrials@gilead.com
• Phone: 1-833-445-3230 (GILEAD-0)

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.