The US Food and Drug Administration (FDA) has approved Hibsago (bepirovirsen), made by GSK, for adults with chronic hepatitis B. Approved on 20 October 2026, it is the first FDA-approved antisense oligonucleotide, a drug that blocks the genetic instructions a virus uses to make its proteins, for the disease.
This article is for general information and is not medical advice.
Who it is for
Hibsago is approved for adults with chronic hepatitis B who:
- do not have cirrhosis (severe liver scarring);
- have taken standard antiviral tablets for at least six months;
- have suppressed levels of the virus in their blood; and
- have a hepatitis B surface antigen (HBsAg) level of 3,000 IU/mL or less.
It is given as injections under the skin for up to 24 weeks, alongside existing antivirals. Patients can inject themselves after the first dose.
The trial results
| Phase III B-Well 1 and 2 trials | Bepirovirsen | Placebo |
|---|---|---|
| Functional cure 24 weeks after stopping all treatment | 19% (233 of 1,220) | 0% (0 of 614) |
| Functional cure if baseline HBsAg ≤1,000 IU/mL | 26% (200 of 768) | — |
| Able to stop standard antivirals | 24% | 0% |
A "functional cure" means the virus is controlled without ongoing treatment. It happens in only about 1% of patients on standard care, according to Pharmaceutical Technology.
Safety
The drug carries two boxed warnings, the FDA's strongest: serious liver reactions and thrombocytopenia (low platelets). Platelets are checked weekly during treatment.
What doctors and GSK say
"This is the start of a new era in treating people living with CHB," said Norah Terrault of the University of Southern California, quoted by ContagionLive. "For the first time, with Hibsago, US patients have the potential to achieve functional cure," said GSK chief scientific officer Tony Wood.
Why it matters
Hepatitis B can cause cirrhosis and liver cancer, and most patients currently take antiviral tablets for life. GSK estimates about 1.7 million people in the US live with chronic hepatitis B. Japan approved the drug first, in August 2026, and GSK expects further approvals in the coming months. It expects peak annual sales of more than £2 billion. The US price and launch date have not been announced.
