Study Details

PROTOCOL 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.

Participation Requirements

Age

18 Years - 70 Years

Sex

ALL

Healthy Volunteers

true

Medical Condition

Chronic Hepatitis Delta

Gender

N/A

Date

July 2025 - February 2029

Study Type

INTERVENTIONAL

Study Phase

PHASE1, PHASE2

Product

GS-4321, GS-4321 Placebo, GS-4321

Eligibility Information

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 ) > 100 IU/mL at screening.
Alanine aminotransferase (ALT) level > 1 × Upper limit of normal (ULN), but < 10 × ULN at screening.

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.

Locations

Locations (15)

Investigative Site

Anaheim, California, United States, 92801

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

Baltimore, Maryland, United States, 21201

The New York-Presbyterian Hospital

New York, New York, United States, 10021

IMSP Spitalul Clinic de Boli Infectioase "Toma Ciorba"

Chinsinau, Moldova, 2004

PMSI Clinical Republican Hospital "Timofei Mosneaga"

Chisinau, Moldova, MD-2025

Institutul National De Boli Infectioase Prof. Dr. Matei Bals

Bucharest, Romania, 021105

Fundatia Dr. Victor Babes

Bucharest, Romania, 030303

Infectious Diseases Institutul National De Boli Infectioase Prof. Matei Bals

Bucharest, Romania, 21105

Gastromedica S.R.L.

Iași, Romania, 700506

Korea University Ansan Hospital

Ansan-si, South Korea, 425-707

The Catholic University of Korea Bucheon St. Mary's Hospital

Bucheon-si, South Korea, 14647

The Catholic University of Korea, Seoul St. Mary's Hospital

Seoul, South Korea, 06591

Samsung Medical Center

Seoul, South Korea, 135-710

Kaohsiung Medical University Chung-Ho Memorial Hospital

Kaohsiung City, Taiwan, 807

Chang Gung Medical Foundation Kaohsiung Chang Gung Memorial Hospital

Kaohsiung City, Taiwan, 83301

Study of GS-4321 in Healthy Participants and Participants With Chronic Hepatitis Delta Virus

OVERVIEW