Biopharmaceutical company GSK plc (LON:GSK) (NYSE:GSK) on Wednesday reported positive phase III B-Well 1 and B-Well 2 trial results for bepirovirsen, an investigational antisense oligonucleotide (ASO) for the treatment of chronic hepatitis B.

The two pivotal phase III trials included a total of more than 1,800 patients across 29 countries. Both trials met the primary endpoint, demonstrating statistically significant and clinically meaningful functional cure rates compared with standard of care alone.

Efficacy was consistent across ranked endpoints, with greater effects observed in patients with baseline surface antigen (HBsAg) under 1,000 IU/ml, and the safety and tolerability profile was acceptable and consistent with prior studies.

Chronic hepatitis B affects more than 250 million people globally and accounts for approximately 56% of liver cancer cases.

GSK plans to initiate global regulatory filings from Q1 2026, supported by presentations at an upcoming scientific congress and publication in a peer-reviewed journal.

Bepirovirsen was licensed from Ionis Pharmaceuticals Inc (Nasdaq:IONS) and has received Fast Track designation from the US FDA, Breakthrough Therapy designation in China, and SENKU designation in Japan.