FDA Approves Hibsago After 19% Functional-Cure Trial

The FDA on October 20, 2026 approved Hibsago (bepirovirsen), a first-in-class antisense oligonucleotide licensed by GSK from Ionis, for chronic hepatitis B in certain adults without cirrhosis. Eligible patients must be on NrtI therapy for at least six months with suppressed HBV DNA and HBsAg at or below 3000 IU/mL. The drug is injected under the skin for up to 24 weeks with existing antivirals, which continue for at least 24 weeks after the last dose; self-administration is allowed after the first dose. Pooled Phase 3 B-Well trials found functional cure in 19% of patients (233 of 1,220) versus 0 of 614 on placebo. Functional cure means undetectable HBV DNA and HBsAg for at least 24 weeks after all treatment stops. Among those with baseline HBsAg at or below 1000 IU/mL, the rate was 26% (200 of 768). Standard care alone typically achieves under 1% after one year. Across the trials, 24% of Hibsago patients met criteria to stop existing medicine, versus none on placebo. The label carries a boxed warning for serious liver reactions and low platelet counts. CONTESTED: No material disputes appear among the sources on the approval date, indication, or trial figures. Ionis CEO Brett P. Monia, USC’s Norah Terrault, Hepatitis B Foundation president Chari Cohen, GSK’s Tony Wood, and FDA’s Wendy Carter each called the approval a meaningful advance. CHB affects about 1.7 million people in the U.S.; GSK is advancing filings abroad.