Sequential Peg-IFN after bepirovirsen may reduce post-treatment relapse in chronic hepatitis B

Results: The intent-to-treat population included 108 participants (Arm 1, n = 55; Arm 2, n = 53). The primary outcome was achieved by 5 (9%) participants in Arm 1 and 8 (15%) in Arm 2. All responders had baseline HBsAg ≤3,000 IU/ml. Indirect comparison with the phase IIb study B-Clear indicates that sequential addition of Peg-IFN may reduce the relapse rates previously observed with bepirovirsen alone. The proportions of participants with adverse events and treatment-related adverse events in both treatment windows were similar between treatment arms. Conclusions: Sequential therapy with bepirovirsen followed by Peg-IFN is tolerable and effective in participants with chronic HBV infection on stable NA therapy. This proof-of-concept trial demonstrates a potential strategy to extend responses to bepirovirsen by reducing relapse. Impact and implications: This phase IIb study investigated whether sequential therapy with bepirovirsen followed by Peg-IFN could improve off-treatment response rates to bepirovirsen alone by converting partial bepirovirsen responders to full responders and/or reducing relapse rates in participants with chronic HBV. These data show that sequential therapy with bepirovirsen followed by Peg-IFN is tolerable and effective; in patients with a bepirovirsen response, sequential treatment with Peg-IFN may help to reduce off-treatment relapses in participants on stable NA. Participants had a similar response during bepirovirsen treatment as seen in B-Clear, with increased response rates in participants with lower baseline HBsAg; all responders to the sequential regimen had baseline HBsAg <3000 IU/mL. As the first study of antisense oligonucleotide-mediated RNA silencing followed by interferon immunomodulation in patients with chronic HBV infection, this study is an important proof-of-concept for sequential therapy, shedding light on the therapeutic potential of utilising immunomodulators following suppression of HBV antigens.