FDA approves GSK and Ionis hepatitis B drug Hibsago

The FDA approved Hibsago, also known as bepirovirsen, to treat chronic hepatitis B in certain adults without cirrhosis. It is the first FDA-approved antisense oligonucleotide for the infection and is given with existing antiviral therapy. Eligible patients must have taken antivirals for at least six months, have suppressed levels of hepatitis B virus in their blood and have HBsAg levels of 3,000 IU/mL or less, determined by an FDA-authorized test.

In two trials, Hibsago was injected for up to 24 weeks. Patients continued their existing hepatitis B medicine for at least 24 weeks after their last injection. The FDA said 24% of patients receiving Hibsago met requirements to stop that medicine, compared with none who received placebo. Twenty-four weeks after stopping all hepatitis B treatment, 19% of Hibsago recipients still had the virus under control, with HBsAg undetectable in their blood.

The FDA’s boxed warning covers serious liver reactions and low platelet counts, which can raise the risk of potentially life-threatening bleeding. The agency said patients need regular blood tests and follow-up during treatment. It also authorized a Roche assay to help identify eligible patients and monitor treatment.