The topline. San Juan, October 23, 2026. For the first time, a drug for chronic hepatitis B can be stopped. The FDA approved Hibsago on October 20, 2026: a finite course of injections, after which about one patient in four controlled the virus with no treatment at all, versus none on placebo. For a disease that usually means lifelong daily antivirals, that is a real step toward functional cure.
Key facts
Most adults with chronic hepatitis B take daily antiviral tablets that suppress the virus but rarely clear it. The chance of a functional cure on standard therapy is about one percent, so treatment usually means years of daily medication.
Hibsago is an antisense oligonucleotide: it targets the genetic material the virus uses to make its proteins, lowering viral RNA and surface antigen (HBsAg) so the immune system can take control after treatment ends. GSK licensed it from Ionis; Japan approved it first, in August 2026.
The indication is carefully drawn: adults without cirrhosis, on antivirals at least six months, with suppressed viral levels and specific HBsAg criteria. The regimen is a 300 mg injection under the skin once a week for up to 24 weeks, alongside existing antivirals. Patients continue regular antivirals for at least 24 weeks after the last injection, and may then stop all treatment if they meet set criteria.
The approval rests on two Phase 3 trials, B-Well 1 and B-Well 2, across 29 countries with more than 1,800 patients already on treatment. Results were strongest in patients starting with lower surface antigen. Among those with HBsAg below 1,000 IU/mL, functional cure reached 25 percent in B-Well 1 and 28 percent in B-Well 2. Baseline labs are not just eligibility criteria; they are prognostic.
Clinical relevance
The safety profile is why this stays a closely managed therapy. Hibsago carries warnings for serious liver reactions, thrombocytopenia, poor kidney function, and inflammatory reactions. In trials, serious side effects of grade 3 or higher occurred in 16 percent of Hibsago patients versus 3 percent on placebo, mostly raised liver enzymes. Patients need regular blood tests and close medical checks.
“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,” said Wendy Carter, DO, acting director of the FDA’s Office of Infectious Diseases.
The FDA granted Fast Track, Breakthrough Therapy, and Priority Review. For clinicians, hepatitis B management now has a finite-course option with a real, if minority, path to stopping treatment.
One in four
That is the share of Hibsago patients who met the criteria to stop all antivirals, and 19 percent still had the virus controlled with no detectable surface antigen 24 weeks after stopping. That sustained, off-treatment control is the functional cure, linked to much lower long-term risks of liver cancer and death. One in four getting there makes it a conversation worth having.