JNJ-64794964 (AL-034/TQ-A3334), a TLR7 agonist, induces sustained anti-HBV activity in AAV/HBV mice via non-cytolytic mechanisms

JNJ-64794964 (JNJ-4964/AL-034/TQ-A3334), an oral toll-like receptor 7 agonist, is being investigated for the treatment of chronic hepatitis B (CHB), a condition with a high unmet medical need. The anti–hepatitis B (HBV) activity of JNJ-4964 was assessed preclinically in an adeno-associated virus vector expressing HBV (AAV/HBV) mouse model. Mice were treated orally with 2, 6 or 20 mg/kg of JNJ-4964 once-per-week for 12 weeks and then followed up for 4 weeks. At 6 mg/kg, a partial decrease in plasma HBV-DNA and plasma hepatitis B surface antigen (HBsAg) was observed, and anti-HBs antibodies and HBsAg-specific T cells were observed in 1/8 animals. At 20 mg/kg, plasma HBV-DNA and HBsAg levels were undetectable for all animals 3 weeks after start of treatment, with no rebound observed 4 weeks after JNJ-4964 treatment was stopped. High anti-HBs antibody levels were observed until 4 weeks after JNJ-4964 treatment was stopped. In parallel, HBsAg-specific immunoglobulin G–producing B cells and interferon-γ–producing CD4+ T cells were detected in the spleen. In 2/4 animals, liver HBV-DNA and HBV-RNA levels and liver hepatitis B core antigen expression dropped 4 weeks after JNJ-4964 treatment-stop. In these animals, HBsAg-specific CD8+ T cells were detectable. Throughout the study, normal levels of alanine aminotransferase were observed, with no hepatocyte cell death (end of treatment and 4 weeks later) and minimal infiltrations of B and T cells into the liver, suggesting induction of cytokine-mediated, non-cytolytic mechanisms.