GSK's Experimental Hepatitis B Drug Achieves Functional Cure in Nearly 1 in 5 Patients in Late-Stage Trials

GSK presented data on May 28, 2026 showing bepirovirsen helped 19% of patients with chronic hepatitis B achieve a functional cure in late-stage studies, rising to 26% in patients with lower surface antigen levels. Current standard treatments help only 1% to 4% of patients clear the virus for a sustained period. GSK has sought regulatory approval in the U.S., Japan, China and Europe, with a U.S. decision expected by October 26, 2026.

Bepirovirsen trial results

• ▪GSK presented detailed data from two studies of bepirovirsen on May 28, 2026 at a medical conference
• ▪Dr. Seng Gee Lim was the lead investigator of the bepirovirsen studies
• ▪Bepirovirsen was generally well tolerated, with most side effects limited to mild injection-site reactions

Functional cure rates

• ▪The functional cure response rate for bepirovirsen rose to 26% among patients with surface antigen levels of 1,000 international units per millilitre or below
• ▪Analysts had estimated a 15% to 20% response rate for bepirovirsen would be significant and could support broad adoption
• ▪Six months of treatment with bepirovirsen helped 19% of patients who started with surface antigen levels of 3,000 international units per millilitre or below achieve a functional cure
• ▪A functional cure for bepirovirsen patients means patients were off treatment for at least six months and had both hepatitis B virus DNA and surface antigen below detectable levels

Current hepatitis B treatment

• ▪More than 250 million people globally live with chronic hepatitis B
• ▪Nucleotide analogues for hepatitis B are often taken for life and suppress the virus but rarely eliminate it
• ▪Current standard-of-care treatments for chronic hepatitis B help only 1% to 4% of patients clear the virus for a sustained period

GSK revenue strategy

• ▪GSK expects peak annual sales of more than £2 billion for bepirovirsen
• ▪Bepirovirsen is central to GSK's plans to achieve more than £40 billion in annual revenue by 2031

Regulatory approval timeline

• ▪GSK has sought regulatory approval for bepirovirsen in the United States, Japan, China and Europe
• ▪A decision from the U.S. regulator on bepirovirsen is expected by October 26, 2026