GSK PLC Detailed B-Well 1 and B-Well 2 data for bepirovirsen in chronic hepatitis confirm a 26% functional cure rate in the <1,000 IU/ml subgroup, upper end of expectations, minor +ve

Research evidence excerpt

GSK PLC Detailed B-Well 1 and B-Well 2 data for bepirovirsen in chronic hepatitis confirm a 26% functional cure rate in the <1,000 IU/ml subgroup, upper end of expectations, minor +ve

C A Z E N O V E Europe Equity Research

28 May 2026

GSK PLC

Detailed B-Well 1 and B-Well 2 data for bepirovirsen in Underweight

chronic hepatitis confirm a 26% functional cure rate in GSK.L, GSK LN

the <1,000 IU/ml subgroup, upper end of expectations, Price (27 May 26):1,940p

minor +ve

European Pharmaceuticals &

This morning, GSK presented detailed results from the B-Well 1 and B-Well 2 Biotechnology

Phase III trials for bepirovirsen in chronic hepatitis B at the EASL 2026 Congress. Zain Ebrahim AC

Bepirovirsen delivered a 19% functional cure benefit in the pooled data from both (44-20) 3493-1163

trials at six months (overall population), which is at the upper end of expectations zain.ebrahim@jpmorgan.com

J.P. Morgan Securities plc

for a 15-20% functional cure. Notably, the efficacy in the <1,000 IU/ml HBsAg

Richard Vosser

level subgroup (lower viral activity) was 26%, slightly ahead of expectations for

(44-20) 7742-6652

20-25%. The efficacy in the 1,000-3,000 IU/ml subgroup (37% of the patient richard.vosser@jpmorgan.com

population enrolled) was more limited at a 7% pooled functional cure rate (10% in J.P. Morgan Securities plc

B-WELL 1 and 5% in B-WELL 2), which could raise questions over the potential Sophia Graeff Buhl Nielsen

breadth of the label and/or potential uptake in this subgroup. On safety, the profile (44-20) 7742-3918

appears broadly manageable, with ≥3x upper limit normal increases in liver sophia.graeffbuhlnielsen@jpmorgan.com

enzymes seen in 22% of bepi treated patients compared with 3% of placebo J.P. Morgan Securities plc