FDA Approves the First Antisense Drug for Hepatitis B

Keypoints:

• The Food and Drug Administration (FDA) approved GSK's Hibsago (bepirovirsen) on 20 October
• It is the first antisense oligonucleotide approved for chronic hepatitis B
• In trials, 24% of patients could stop their antiviral medicines, against none on placebo
• 19% maintained viral control 24 weeks after treatment
• Japan authorized the drug in August

The FDA approved Hibsago, an injection made by GSK, for chronic hepatitis B infection. It is the first antisense oligonucleotide approved for the condition. The agency called it a first-of-its-kind treatment. Hibsago is used alongside existing antivirals.

Chronic hepatitis B usually means years of daily medication. Current antivirals suppress the virus but rarely clear it. The new drug works differently. It targets the viral RNA, the instructions the virus uses to make its proteins. Reducing those proteins may let the immune system regain control.

The approval is narrow. It covers adults without cirrhosis, or advanced liver scarring. Patients must have taken hepatitis B antiviral therapy for at least six months and have suppressed viral DNA. Their hepatitis B surface antigen level must be 3,000 IU/mL or lower, measured with an FDA-authorized test. The FDA also authorized Roche's Elecsys HBsAg II quant II RxDx assay to select and monitor patients.

Trial results show why it matters. Among patients who received Hibsago, 24% were able to discontinue their antiviral medicines. None of those on placebo could. A total of 19% maintained viral control 24 weeks after treatment. Only patients who meet the required health and laboratory criteria may stop antivirals afterward, and only under medical supervision.

The approval follows an earlier one in Japan in August. It also opens a new treatment category. Antisense drugs are designed to match a specific genetic sequence, which allows precise targeting. This one is aimed at a virus that affects millions of people worldwide.