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A 300-mg dose of bepirovirsen per week for 24 weeks results in sustained hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) DNA loss in 9–10% of patients with chronic HBV infection, according to a study published online Nov. 8 in the New England Journal of Medicine.
Man-Fung Yuen, M.D., Ph.D., D.Sc., from the Queen Mary Hospital and the University of Hong Kong, and colleagues conducted a phase 2b trial involving participants with chronic HBV infection who were receiving or not receiving nucleoside or nucleotide analog (NA) therapy (227 and 230 participants, respectively).
Participants were randomly assigned to receive weekly subcutaneous injections of bepirovirsen 300 mg for 24 weeks; 300 mg for 12 weeks then 150 mg for 12 weeks; 300 mg for 12 weeks then placebo for 12 weeks; or placebo for 12 weeks then bepirovirsen 300 mg for 12 weeks (groups 1, 2, 3, and 4, respectively). An HBsAg level below the limit of detection and an HBV DNA level below the limit of quantification maintained for 24 weeks after the planned end of bepirovirsen treatment was the composite primary outcome.
The researchers found that a primary outcome event occurred in 9, 9, 3, and 0% of patients in groups 1, 2, 3, and 4, respectively, among those receiving NA therapy and in 10, 6, 1, and 0% among those not receiving NA therapy. Adverse events were more common with bepirovirsen and included injection-site reactions, pyrexia, fatigue, and increased alanine aminotransferase levels.
“Larger trials and longer follow-up are needed to assess the safety and efficacy of bepirovirsen,” the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including GlaxoSmithKline, which manufactures bepirovirsen and funded the study.