The US FDA has approved bepirovirsen (Hibsago) in combination with nucleos(t)ide analog reverse transcriptase inhibitor (NrtI) therapy for adults with chronic hepatitis B virus (HBV) infection without cirrhosis who have received NrtI therapy for at least 6 months, have suppressed HBV DNA, and have hepatitis B surface antigen (HBsAg) levels ≤3,000 IU/mL. Mechanism of Action Bepirovirsen is an HBV mRNA-directed antisense oligonucleotide. Clinical Evidence In the Phase 3 B-Well 1 and B-Well 2 trials, sustained suppression of HBV DNA with undetectable HBsAg 24 weeks after discontinuing all HBV treatment was achieved in participants with baseline HBsAg levels ≤3,000 IU/mL: B-Well 1: 20% with Hibsago versus 0% with placebo.

B-Well 2: 19% with Hibsago versus 0% with placebo. Dosage and Administration Weeks 1–2: 300 mg subcutaneously twice weekly, with 3–4 days between doses. Weeks 3–24: 300 mg…