WASHINGTON — The Food and Drug Administration approved Hibsago, or bepirovirsen, on Tuesday as the first antisense oligonucleotide treatment for chronic hepatitis B.
The approval is limited to certain adults without cirrhosis. Eligible patients must already have taken hepatitis B antiviral therapy for at least six months, have suppressed virus levels and have hepatitis B surface antigen levels of 3,000 IU/mL or less on an FDA-authorized test. Hibsago is used with existing antiviral treatment, not as a replacement at the start of therapy.
The medicine is injected under the skin for up to 24 weeks. Patients continue their existing antiviral for at least 24 weeks after the final injection. Some may later meet laboratory and health criteria to stop that medicine.
Across two trials, the FDA said 24% of Hibsago recipients met the criteria to stop existing medicine, compared with none receiving placebo. Twenty-four weeks after stopping all hepatitis B treatment, 19% of recipients still had viral control and no detectable hepatitis B surface antigen.
Hibsago carries a boxed warning for serious liver reactions and low platelet counts that can raise the risk of life-threatening bleeding. Other warnings include worsening kidney function, serious inflammatory reactions and injection-related risks. Regular blood tests and medical follow-up are required. Common side effects outside laboratory abnormalities included injection-site reactions, fever, fatigue and headache.
The FDA granted the approval to GSK. Patients should discuss eligibility, benefits and risks with a qualified clinician rather than changing treatment on their own.
Source: U.S. Food and Drug Administration approval announcement, Oct. 20, 2026.
