FDA Approves Hibsago: First Antisense Drug for Chronic Hepatitis B

On October 20, 2026, the FDA approved Hibsago (bepirovirsen), GSK's antisense oligonucleotide injection, as the first treatment of its class for chronic hepatitis B (CHB). The drug targets the genetic instructions the hepatitis B virus uses to replicate, reducing both viral load and hepatitis B surface antigen (HBsAg) in the blood. It is intended for adults without cirrhosis who have been on antiviral therapy for at least six months, have suppressed viral levels, and have HBsAg at or below 3,000 IU/mL as confirmed by an FDA-authorised test. Hibsago is injected under the skin for up to 24 weeks alongside existing antivirals; patients who respond may then stop all hepatitis B treatment entirely. Across two clinical trials, 24% of Hibsago recipients met the criteria to discontinue their existing medication, compared with zero in the placebo arm. Twenty-four weeks after stopping all treatment, 19% of those patients still had the virus under control with undetectable HBsAg. The drug carries a boxed warning for serious liver reactions, low platelet counts and kidney complications. The FDA granted Hibsago Fast Track, Breakthrough Therapy and Priority Review designations. Chronic hepatitis B affects an estimated 300 million people worldwide and can lead to liver cirrhosis and liver cancer.