GSK plc Announces FDA Acceptance of Bepirovirsen for Priority Review and Breakthrough Therapy Designation

GSK plc announced that the US FDA has accepted for priority review their New Drug Application (NDA) for bepirovirsen, an investigational antisense oligonucleotide, for the treatment of adults with chronic hepatitis B (CHB). Bepirovirsen has also received Breakthrough Therapy Designation (BTD), recognizing its potential for substantial improvement over available therapies. This designation builds on the existing Fast Track Designation granted in February 2024. The submissions are supported by positive Phase III B-Well 1 and B-Well 2 trials, which demonstrated statistically significant and clinically meaningful functional cure rates. Chronic hepatitis B affects over 250 million people globally, and current treatments often require lifelong therapy with low functional cure rates. Bepirovirsen aims to achieve a functional cure by inhibiting viral replication, suppressing hepatitis B surface antigen levels, and stimulating the immune system. The FDA has set a PDUFA goal date of October 26, 2026. Bepirovirsen is a collaboration between GSK and Ionis Pharmaceuticals and is not yet approved anywhere in the world.