FDA approves GSK's Hibsago for chronic hepatitis B

The U.S. Food and Drug Administration approved GSK’s Hibsago (bepirovirsen) injection on October 20, 2026, for chronic hepatitis B virus infection in certain adults without cirrhosis. The drug is used in combination with existing antiviral therapy, and the FDA described it as the first antisense oligonucleotide approved for chronic hepatitis B.

To be eligible, patients must be adults without cirrhosis who have taken an antiviral for hepatitis B for at least six months, have suppressed HBV levels, and have an HBsAg level of 3,000 IU/mL or less on an FDA-authorized test. The Roche Elecsys HBsAg II quant II RxDx assay also received authorization from the agency as a companion diagnostic to help select and monitor patients.

Chronic hepatitis B is a persistent infection of the liver that can lead to cirrhosis and raise the risk of liver cancer. Hibsago targets the virus’s genetic instructions for making copies of itself and viral proteins, which reduces virus and HBsAg levels. The drug is injected subcutaneously for up to 24 weeks. Patients continue their existing hepatitis B medicine for at least 24 weeks after the last Hibsago injection; some may then stop that medicine if they meet health and lab test requirements.

Hibsago was studied in two placebo-controlled trials. In the two trials, 24% of patients who received Hibsago qualified to discontinue their existing medicine, while none on placebo did. At 24 weeks after all hepatitis B treatment ended, 19% of the Hibsago group still had viral control and no detectable HBsAg.

The drug carries a boxed warning for serious liver reactions and low platelet counts, a condition that can raise the risk of life-threatening bleeding. Other warnings cover worsening kidney function, serious inflammatory reactions such as vasculitis, and hazards from incorrect injection technique. Patients require periodic blood testing and medical follow-up before and during treatment. The most common side effects, aside from abnormal lab results, were reactions at the injection site, fever, tiredness, and headache.

The agency granted the drug Fast Track and Breakthrough Therapy status and Priority Review. GSK plc holds the approval. Wendy Carter, DO, acting head of the Office of Infectious Diseases within the Center for Drug Evaluation and Research, said, “Hibsago provides a new treatment approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended.”

Update, October 24, 2026

Drug Discovery News reported that the FDA based its approval on results from two B-WELL phase 3 trials, identifying the studies by name and phase. It also quoted an additional sentence from Wendy Carter's statement in the agency's press release: "This approval represents an important advance for people living with this serious disease." The outlet noted that Hibsago is the first among a competitive field of hepatitis B candidates to receive approval, while therapeutic options from Brii Biosciences are now lagging behind.