JNJ-73763989 and bersacapavir treatment in nucleos(t)ide analog suppressed patients with chronic hepatitis B: REEF-2

Background & Aims Functional cure (FC) for chronic hepatitis B (CHB) requires finite treatment. Two agents under investigation aimed at achieving FC are small interfering RNA JNJ-73763989 (JNJ-3989) and capsid assembly modulator JNJ-56136379 (JNJ-6379; bersacapavir). Methods REEF-2, a phase 2b, double-blind, placebo-controlled, randomized study (ClinicalTrials.gov Identifier: NCT04129554), enrolled 130 nucleos(t)ide analog (NA)–suppressed hepatitis B e-antigen (HBeAg)–negative CHB patients who received JNJ-3989 (200 mg subcutaneously every 4 weeks)+JNJ-6379 (250 mg oral daily)+NA (oral daily; active arm) or placebos for JNJ-3989 and JNJ-6379 + active NA (control arm) for 48 weeks followed by 48 weeks off-treatment follow-up. Results At Follow-up Week 24, no patients achieved the primary endpoint of FC (off-treatment hepatitis B surface antigen [HBsAg] seroclearance). No patients achieved FC at Follow-up Week 48. There was pronounced on-treatment reduction in mean HBsAg from baseline at Week 48 in the active arm versus no decline in the control arm (1.89 vs 0.06 log10 IU/mL; P = 0.001). At Follow-up Week 48, reductions from baseline were >1 log10 IU/mL in 81.5% versus 12.5% of patients in the active and control arms, respectively, and 38/81 (46.9%) patients in the active arm achieved HBsAg <100 IU/mL versus 6/40 (15.0%) patients in the control arm. Off-treatment HBV DNA relapse and alanine aminotransferase (ALT) increases were less frequent in the active arm with 7/77 (9.1%) and 11/41 (26.8%) patients in the active and control arms, respectively, restarting NA during follow-up. Conclusions Finite 48-week treatment with JNJ-3989+JNJ-6379+NA resulted in fewer and less severe posttreatment HBV DNA increases and ALT flares, and a higher proportion of patients with off-treatment HBV DNA suppression, with or without HBsAg suppression, but did not result in FC. ClinicalTrials.gov Identifier NCT04129554