GSK, Ionis Win FDA Approval for First-of-Its-Kind Hepatitis B Drug Hibsago

The Food and Drug Administration on Tuesday approved Hibsago, a first-of-its-kind hepatitis B therapy from GSK and Ionis Pharmaceuticals, clearing it for use alongside standard antivirals in certain adults with chronic infections who have not developed cirrhosis. Regulators recommend it for patients on antivirals at least six months with suppressed virus levels. The RNA-based medicine, given as periodic injections over six months, aims to achieve a "functional cure" — undetectable virus and related proteins for at least 24 weeks. In two late-stage studies, the Hibsago-antiviral combination cleared the virus in about a fifth of recipients versus none on placebo plus antivirals. GSK did not disclose a list price, saying it will be revealed after pricing and reimbursement talks with payers. The FDA labeling carries a safety warning for sudden liver inflammation or enzyme spikes and low platelet counts, with recommended weekly or bi-weekly lab tests — requirements Jefferies analyst Michael Leuchten wrote may slow commercial uptake. He still expects roughly $3 billion in peak annual sales. Hibsago is already approved in Japan and under review in China and Europe.