GSK reported phase 3 readouts for bepirovirsen, an antisense oligonucleotide designed to target hepatitis B virus (HBV) transcripts, with “functional cure” after treatment discontinuation in a subset of noncirrhotic, chronic HBV patients. In two replicate trials (B-Well 1 and B-Well 2), 20% and 19% of patients respectively achieved functional cure at week 72 after stopping background nucleos(t)ide analogue therapy, versus none in placebo arms. GSK said safety signals included higher rates of adverse events and grade 3+ events in the bepirovirsen groups than placebo, with alanine aminotransferase increases among the most common grade 3 adverse events. The company framed the results as the first time bepirovirsen produced significantly higher functional cure rates than the standard of care regimen plus placebo comparator when NA therapy is discontinued. Regulatory and commercial implications are immediate given HBV’s global burden and the effort to move beyond virologic suppression toward sustained markers of cure. The trial was funded by GSK and registered on ClinicalTrials.gov (NCT05630807 and NCT05630820).