— "Start of a new era," says trial investigator
October 20, 2026 • 2 min read
The FDA on Tuesday approved bepirovirsen (Hibsago)opens in a new tab or window as a potential functional cure for adults with chronic hepatitis B, but with no cirrhosis, who are taking antiviral therapy.
Approval was based on findings from the B-Well 1 and B-Well 2opens in a new tab or window trials, which demonstrated that nearly 1 in 5 patients taking the antisense oligonucleotide drug along with background antivirals achieved a functional cure, as compared with none in a placebo group.
"This is the start of a new era in treating people living with [chronic hepatitis B]," said investigator Norah Terrault, MD, of Keck School of Medicine at the University of Southern California in Los Angeles, in a statementopens in a new tab or window from drugmaker GSK. "Bepirovirsen offers patients the potential to achieve functional cure after a short period of treatment, a long-standing goal for patients and physicians alike."
In the phase III trials, 19-20% of patients with hepatitis B surface antigen (HBsAg) levels of 3,000 IU/mL or less had a functional cure with bepirovirsen at week 72. In those with HBsAg levels of 1,000 IU/mL -- about 45% of diagnosed cases worldwide -- the functional cure rate reached 26%.
Chronic hepatitis B virus (HBV) infection can cause serious liver disease, including cirrhosis, and more than half of liver cancer cases globally can be attributed to hepatitis B.
Bepirovirsen is given as a 6-month course and can be self-administered after the first dose. The indication stipulates use along with nucleos(t)ide analog reverse transcriptase inhibitor therapy in patients who have taken antiviral therapy for at least 6 months, have suppressed HBV blood levels, and have HBsAg levels of 3,000 IU/mL or less.
Bepirovirsen "provides a new treatment approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended," said Wendy Carter, DO, of FDA's Center for Drug Evaluation and Research. "This approval represents an important advance for people living with this serious disease."
The most common side effects are injection site reactions, fatigue, fever, and headache.
The FDA's approved prescribing information opens in a new tab or windowincludes a boxed warning about serious hepatic flares during treatment and low platelet counts, which can cause life-threatening thrombocytopenia. Other warnings include risks of worsening kidney function, serious inflammatory adverse reactions such as vasculitis, and serious risks from improper injection. Because of those risks, patients using bepirovirsen require regular blood tests. Bepirovirsen is not recommended in patients with hepatitis D virus coinfection.