Arbutus’ Lead Compound AB-729 Continues to be Safe and Effective at Reducing HBsAg in Patients with Chronic Hepatitis B
HBsAg remains suppressed up to 28 weeks after discontinuation of AB-729
Repeat dosing of both 60 mg and 90 mg of AB-729 results in comparable HBsAg reductions
WARMINSTER, Pa., Nov. 10, 2021 (GLOBE NEWSWIRE) — Arbutus Biopharma Corporation (NASDAQ:ABUS), a clinical-stage biopharmaceutical company primarily focused on discovering, developing and commercializing a broad portfolio of wholly-owned assets with different modes of action to provide a cure for people with chronic hepatitis B virus (HBV) infection and to treat coronaviruses (including COVID-19), today announced new AB-729 safety and efficacy data, as well as long-term data from HBV patients following discontinuation of treatment with AB-729. The data are from part 3 of the Company’s ongoing Phase 1a/1b clinical trial with 60 mg or 90 mg of AB-729 dosed every four, eight or 12 weeks. The data will be presented at AASLD in a poster entitled, “Low HBsAg levels maintained following cessation of the GalNAc-siRNA, AB-729, in chronic hepatitis B subjects on nucleos(t)ide analogue therapy”.
Data from the poster presentation include long-term follow-up data for patients in cohort E (60 mg every four weeks) and cohort F (60 mg every eight weeks) who had been off AB-729 treatment for six months. Suppression of HBsAg to levels <100 IU/mL were maintained up to 24 weeks off-treatment in 3 of 7 patients in cohort E and 1 of 3 patients with available data in cohort F. Patients who remain below this clinically relevant threshold for six months after stopping AB-729 treatment could consider discontinuing their nucleos(t)ide analogue (“NA”) therapy to assess the potential for functional cure.
Professor Man-Fung Yuen, D.Sc., M.D., Ph.D., Deputy Head of Department Medicine and Chief of Division of Gastroenterology and Hepatology, University of Hong Kong, and lead investigator of Arbutus’ Phase 1a/1b clinical trial, stated, “I find this long-term off-treatment data very encouraging. Albeit small patient numbers, these data give us confidence that AB-729 is capable of reducing and maintaining suppression of HBsAg even after its discontinuation. We look forward to providing additional long-term follow up data on these patients, especially as some of them may elect to discontinue their NA therapy.”
Also included in the poster presentation are data showing that robust mean declines (ranging from 1.8-2.0 log10 at week 40) in HBsAg were sustained with repeat dosing of AB-729 up to 48 weeks, with no statistically significant differences observed to date between the 60 mg and 90 mg dose and/or dosing intervals.
Mean (SE) Baseline Change in HBsAg with Repeat Dosing of AB-729
60 mg Q4W
60 mg Q8W
90 mg Q8W
90 mg Q12W
90 mg Q8W