GSK Plc and its partner Ionis Pharmaceuticals Inc. received a major boost as the U.S. Food and Drug Administration accepted their drug, bepirovirsen, for Priority Review to treat chronic hepatitis B, setting an action date of October 26, 2026.
"As the first medicine to deliver clinically meaningful functional cure rates, bepirovirsen is uniquely positioned to effectively treat CHB," Brett P. Monia, Ionis' chief executive officer, said. "This milestone reflects the broad impact of Ionis’ science, and we look forward to the potential for bepirovirsen to help millions of people."
The FDA also granted the drug Breakthrough Therapy designation, a status reserved for medicines that may offer substantial improvement over existing options. The regulatory submission was supported by data from the Phase 3 B-Well 1 and B-Well 2 studies, which demonstrated that bepirovirsen achieved statistically significant rates of functional cure—a state where the virus is undetectable without medication. Current treatments for the more than 1.7 million U.S. patients with chronic hepatitis B offer functional cure rates of only about 1% and often require lifelong therapy.
Bepirovirsen, an antisense oligonucleotide, works by reducing the hepatitis B virus's ability to replicate and produce viral proteins, while also stimulating the immune system. GSK licensed the drug from Ionis in 2019 and is also pursuing regulatory approval in Europe, China, and Japan. Under the agreement, Ionis is eligible for milestone payments and tiered royalties of 10-12% on net sales.
The positive FDA update positions bepirovirsen as a potential first-in-class treatment for a disease affecting over 250 million people globally. Investors will now watch for the full data presentation at the European Association for the Study of the Liver (EASL) 2026 Congress in May.
This article is for informational purposes only and does not constitute investment advice.
