Arbutus Announces Robust HBsAg Decline Data with AB-729 Dosed at 60 mg Every 8 Weeks in Chronic Hepatitis B Subjects

Repeat dosing of 60 mg AB-729 every 8 weeks resulted in mean HBsAg declines of –1.37 log10 (N=6) comparable to AB-729 dosed every 4 weeks (–1.44 log10, N=7, p<0.7)

AB-729 remains generally safe and well tolerated with no SAEs or treatment discontinuations in any cohort

WARMINSTER, Pa., Dec. 10, 2020 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS), a clinical-stage biopharmaceutical company primarily focused on developing a cure for people with chronic hepatitis B virus (HBV) infection as well as therapies to treat coronaviruses (including COVID-19), today announced additional clinical data from an ongoing Phase 1a/1b clinical trial (AB-729-001) with AB-729, its proprietary GalNAc delivered RNAi compound.

William Collier, President and Chief Executive Officer of Arbutus, stated, “Throughout 2020, Arbutus has reported data that demonstrate the robust safety and efficacy of AB-729 in multiple patient cohorts. These data support advancing AB-729 into phase 2a clinical studies in 2021 and further support our confidence in its potential to become a cornerstone drug in future combination regimens to cure chronic hepatitis B.”

Summary of new data

Repeat dosing of AB-729 60 mg every 4 and 8 weeks results in comparable declines in mean HBsAg through week 16

Δlog10 HBsAg/(SE) (IU/mL)	Mean (SE) Week 12	Mean (SE) Week 16	Mean (SE) Week 24
Cohort E Q4W (N=7)	-1.10 (0.15)	-1.44 (0.18)	-1.84 (0.16)
Cohort F Q8W (N=7)	-1.02 (0.11)	-1.37* (0.08)	N/A**

*Mean determined based on N=6 since one subject has not reached week 16.
**Data not yet available since none of the subjects have reached week 24.

Dr. Gaston Picchio, Chief Development Officer of Arbutus, commented, “The mean reduction in HBsAg seen at week 16 in Cohort F suggests that AB-729 could offer patients the advantage of being dosed every 8 weeks versus every 4 weeks. Further dosing should allow us to confirm this finding.”

Dr. Picchio added, “Importantly, safety continues to be unremarkable. We have not seen any related Grade 3/4 AEs or treatment-related discontinuations in any cohorts to date. In Cohort F, two subjects had asymptomatic ALT elevations not considered AEs; one subject with Grade 1 ALT elevations prior to trial entry has had intermittent Grade 2 elevations, while another subject had a transient Grade 1 elevation which resolved with continued treatment.