A5368:Anti-PD-1 Antibody in HBV Infected on Suppressive Antiviral Therapy

“Safety and Immunotherapeutic Activity of Cemiplimab in Participants with HBV on Suppressive Antiviral Therapy: A Phase I/II Ascending Multiple Dose Study”

Scientists are looking at ways to cure Hepatitis B (HBV). This study will assess the safety and tolerability of cemiplimab administered in participants with HBV on suppressive antiviral therapy.

This study is trying to find out if cemiplimab is safe and well tolerated. Participants will receive multiple dose levels (0.3, 1.0, and 3.0 mg/kg) of cemiplimab administered as two infusions at weeks 6 and 12.

• Have chronic HBV infection (defined as HBsAg positive) and under treatment for ≥12 months with tenofovir- or entecavir-containing therapy: tenofovir disoproxil fumarate (TDF), tenofovir alanfenamide (TAF), TDF/emtricitabine (FTC), TAF/FTC, or entecavir.
• Be willing to continue HBV antiviral therapy throughout the study.
• Have certain tests done.
• Agree to use contraception/birth control methods.
• Be 18 years old or older but less than 70 years.
• Weight ≥40 kg.
• Had evidence of limited or no evidence of fibrosis (F0-F2) by liver biopsy or noninvasive alternative method.
• Be willing to sign the consent after discussion with the research staff.

Exclusion Criteria (things that cannot be true about you):

• Positive for the presence of Hepatitis C Virus.
• Received investigational drug or device within 60 days prior to study entry.
• Breastfeeding or pregnancy.
• Known allergy/sensitivity or any hypersensitivity to components of study drug(s).
• Active drug or alcohol use or dependence and other conditions that would interfere with adherence to study.
• Acute or serious illness requiring systemic treatment and/or hospitalization within 35 days prior to study entry.
• History of immunoglobulin IgG therapy or interferon (IFN) therapy within 12 months prior to study entry.
• A male participant with a pregnant female partner.
• Any vaccination within 30 days prior to entry.

• Blood tests at clinic visits to check mainly hepatic and renal function.
• Liver biopsy at study entry and at week 18 on study.
• Leukapheresis for a group of participants.

• Multiple dose levels (0.3, 1.0 and 3.0 mg/kg) of cemiplimab administered as two infusions at weeks 6 and 12.

Participants will be on study for up to 90 weeks (78 weeks following the last study drug infusion) with frequent safety evaluations.