Recruiting
Phase 1
Phase 2

GS-4321

Sponsor:

Gilead Sciences

Code:

NCT07096193

Conditions

Chronic Hepatitis Delta

Eligibility Criteria

Sex: All

Age: 18 - 69

Healthy Volunteers: Accepted

Interventions

GS-4321

GS-4321 Placebo

GS-4321

Study Details

Brief summary:

The goals of this clinical study are to first learn more about safety and dosing of the study drug GS-4321 in healthy participants. The study will then learn about the safety and effectiveness of GS-4321 in participants with chronic hepatitis delta (CHD).

The primary objective of Phase 1 of this study is to evaluate the safety, tolerability and Pharmacokinetics (PK) of the escalating single doses of GS-4321 administered in healthy participants.

The primary objective of Phase 2 of this study is to evaluate the efficacy and safety of the multiple escalating doses of GS-4321 in participants with CHD.

Conditions

Chronic Hepatitis Delta

Study ID

NCT07096193

Start date

Jul 31, 2025

Status verified date

Aug, 2026

Completion date

Jan, 2030

Anticipated

Primary completion date

Jan, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 69

Healthy Volunteers: Accepted

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.

Study Design

Enrollment

200 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Phase 1: GS-4321

Participants will receive single escalating doses of GS-4321.

placebo comparator: Phase 1: Placebo

Participants will receive placebo to match the single escalating doses of GS-4321

experimental: Phase 2: GS-4321

Participants will receive multiple escalating doses of GS-4321 up to 96 weeks.

Interventions

GS-4321

Administered subcutaneous (SC) or intravenously IV

GS-4321 Placebo

Administered SC

GS-4321

Administered SC

Primary outcome measure

  • Phase 1 and 2: Percentage of Participants With Treatment-emergent Adverse Events [ Time Frame: Phase 1: First dose up to 44 weeks; Phase 2: First dose up to 96 Weeks plus 48 weeks of posttreatment follow-up ]
  • Phase 1 and 2: Percentage of Participants With Treatment-emergent Serious Adverse Events [ Time Frame: Phase 1: First dose up to 44 weeks; Phase 2: First dose up to 96 Weeks plus 48 weeks of posttreatment follow-up ]
  • Phase 1 and 2: Percentage of Participants Experiencing Treatment-emergent Clinical Laboratory Abnormalities [ Time Frame: Phase 1: First dose up to 44 weeks; Phase 2: First dose up to 96 Weeks plus 48 weeks of posttreatment follow-up ]
  • Phase 1: Serum Pharmacokinetic (PK) parameter; AUC of GS-4321 [ Time Frame: First dose up to 24 Weeks ]
  • Phase 1: Serum PK Parameter: Cmax [ Time Frame: First dose up to 24 Weeks ]
  • Phase 1: Serum PK Parameter: Tmax [ Time Frame: First dose up to 24 Weeks ]
  • Phase 1: Serum PK Parameter: t1/2 [ Time Frame: First dose up to 24 Weeks ]
  • Phase 2: Proportion of Participants with Combined Response [ Time Frame: Up to 96 Weeks ]

Central Contacts and Locations

Central contacts

Gilead Clinical Study Information Center

1-833-445-3230 (GILEAD-0)GileadClinicalTrials@gilead.com

Locations

Investigative Site

Recruiting

Anaheim, California, United States, 92801

University of California, San Diego - Altman Clinical and Translational Research Institute

Recruiting

La Jolla, California, United States, 92093

University of Louisville, Clinical Trials Unit

Recruiting

Louisville, Kentucky, United States, 40202

University of Maryland, Institute of Human Virology, Clinical Research Unit

Recruiting

Baltimore, Maryland, United States, 21201

The New York-Presbyterian Hospital

Recruiting

New York, New York, United States, 10021

More Information

Sponsor

Gilead Sciences

Last update posted

Aug 27, 2026

Last verified

Aug, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Gilead Sciences on 2026-08-27.