An experimental hepatitis B drug from GSK achieved a 19% functional cure rate in phase 3 trials, offering new hope for treating the chronic liver infection. Bepirovirsen, administered alongside standard antivirals for six months, enabled patients to naturally control the virus without further treatment, according to results published in The New England Journal of Medicine.

Unlike traditional nucleoside analogs that disrupt viral DNA replication, bepirovirsen is an antisense oligonucleotide that binds to HBV messenger RNA, blocking protein production and triggering immune responses. In the study of over 1,800 participants across 29 countries, 233 of 1,220 patients receiving the drug achieved functional cures compared to zero in the placebo group.

The findings address a major global health challenge: 240 million people worldwide live with chronic hepatitis B, which kills approximately 1.1 million annually. Current treatments require lifelong medication, with fewer than 1% of patients maintaining viral control after stopping therapy. Only 27% of infected individuals have received diagnoses, and less than 5% access treatment.

Researchers caution that durability remains uncertain, though phase 2 data shows viral suppression lasting up to three years in most cured patients. GSK has submitted regulatory applications in Europe, the US, Canada, Japan, and China, expecting approvals later this year. The drug's impact may be limited since trials focused on patients already responding well to existing treatments.