Arbutus Announces Single-Dose Week 12 Data in Chronic Hepatitis B Subjects with 60 mg AB-729 Demonstrating a Significant and Continuous Reduction in HBsAg

Mean 60 mg HBsAg reduction of 0.99 log10 IU/mL at week 12, with normal ALT and AST values throughout the follow-up period

90 mg single-dose and 60 mg multi-dose cohorts initiated with data expected in the second half of 2020

WARMINSTER, PA, USA I May 18, 2020 I Arbutus Biopharma Corporation (Nasdaq: ABUS), a clinical-stage biopharmaceutical company focused on developing a cure for people with chronic hepatitis B virus (HBV) infection, today reports positive follow-up data from a Phase 1a/1b clinical trial (AB-729-001) in chronic HBV subjects on nucleos(t)ide therapy who received a single subcutaneous injection of 60 mg of AB-729, a proprietary GalNAc delivered RNAi compound. 

William Collier, President and Chief Executive Officer of Arbutus, stated, “These new data further demonstrate the robust activity of AB-729. At week 12, the 60 mg single-dose achieved equivalent reductions in HBsAg as the 180 mg single-dose. We are currently dosing chronic HBV subjects in a multi-dose cohort with 60 mg of AB-729. These data keep us on track for achieving our goal of delivering a combination therapy that includes HBsAg reduction in chronic hepatitis B subjects.”

Mean HBsAg changes from baseline:

  60 mg Single-Dose Cohort
180 mg Single-Dose Cohort
Day 29 mean log10 IU/mL
(Standard Error of the Mean)
-0.24 (0.13) -0.8 (0.38)
Week 12 (day 84) mean log10 IU/mL
(Standard Error of the Mean)
-0.99 (0.24) -0.98 (0.22)

Dr. Gaston Picchio, Chief Development Officer of Arbutus, stated, “Importantly, throughout the 12 week period, not only does AB-729 demonstrate robust HBsAg reduction, it does so while remaining generally safe and well tolerated with no abnormal transaminase values in any of the six subjects.”

Dr. Picchio added, “We are impressed by both the magnitude and continuous reduction in HBsAg achieved with a single 60 mg dose. We believe that these features could provide a competitive advantage with a low dose and reduced frequency of injections. To this end, we are currently dosing chronic HBV subjects in a multi-dose cohort with 60 mg at 4 week intervals and also intend to evaluate 60 mg at 8 week intervals, which will begin as soon as possible.  As we previously announced we are also exploring an additional 90 mg single-dose cohort. We expect data from both the 60 mg multi-dose cohorts in the second half of the year. We also expect week 12 90 mg single-dose data in the second half of 2020.”

Summary of clinical trial design

AB-729-001 is an ongoing first-in-human clinical trial consisting of three parts:

  • In Part 1, three cohorts of healthy subjects were randomized 4:2 to receive single-doses (60 mg, 180 mg or 360 mg) of AB-729 or placebo.
  • In Part 2, non-cirrhotic, HBeAg positive or negative, chronic HBV subjects (N=6) on a background of nucleos(t)ide therapy with HBV DNA below the limit of quantitation received single-doses (60 mg or 180 mg) of AB-729. An additional cohort in Part 2 is designed to include 90 mg single-dose of AB-729 in HBV DNA positive chronic HBV subjects.
  • In Part 3, chronic HBV subjects, HBV DNA negative first and HBV DNA positive later, will receive multi-doses of AB-729 for up to six months.


In December 2019 an outbreak of a novel strain of coronavirus (COVID-19) was identified in Wuhan, China. This virus continues to spread globally, has been declared a pandemic by the World Health Organization and has spread to nearly every country in the world. The impact of this pandemic has been, and will likely continue to be, extensive in many aspects of society. The pandemic has resulted in and will likely continue to result in significant disruptions to businesses. A number of countries and other jurisdictions around the world have implemented extreme measures to try and slow the spread of the virus.  These measures include the closing of businesses and requiring people to stay in their homes, the latter of which raises uncertainty regarding the ability to travel to hospitals in order to participate in clinical trials. Additional measures that have had, and will likely continue to have, a major impact on clinical development, at least in the near-term, include shortages and delays in the supply chain, and prohibitions in certain countries on enrolling subjects in new clinical trials.  While we have been able to progress with our clinical and pre-clinical activities to date, it is not possible to predict if the COVID-19 pandemic will negatively impact our plans and timelines in the future.  

About Arbutus

Arbutus Biopharma Corporation is a publicly traded (Nasdaq: ABUS) biopharmaceutical company dedicated to discovering, developing and commercializing a cure for people with chronic Hepatitis B (HBV) infection. The Company is advancing multiple drug product candidates that may be combined into a potentially curative regimen for chronic HBV infection. For more information, visit

SOURCE: Arbutus Biopharma

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