Arbutus Announces Presentation of Phase 1a/1b Clinical Trial Results for AB-729 in Chronic Hepatitis B Subjects at The Liver Meeting Digital Experience™, The American Association for the Study of Liver Diseases Meeting

Across all single-dose cohorts, mean HBsAg concentrations continuously declined up to week 12 before reaching a plateau, suggesting dosing of AB-729 less frequently than every 4 weeks may be warranted

In the 60 mg every 4 weeks multi-dose cohort, HBsAg concentrations continued to decline steadily beyond week 12 with no plateau in response observed to date

Both HBV RNA and HBcrAg concentrations declined after single- and multi-dose administration of AB-729

AB-729 was generally safe and well tolerated

WARMINSTER, PA, USA I November 15, 2020 I 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 the presentation of updated clinical data from an ongoing Phase 1a/1b clinical trial (AB-729-001) with AB-729, its proprietary GalNAc delivered RNAi compound. The presentation, entitled Safety and pharmacodynamics of the GalNAc-siRNA AB-729 in subjects with chronic hepatitis B infection, was presented by Professor Man-Fung Yuen, D.Sc., M.D., Ph.D., Chief of Division of Gastroenterology and Hepatology, Department of Medicine, The University of Hong Kong, Hong Kong, during a virtual oral session: Hepatitis B: Therapeutics (New) at The Liver Meeting Digital ExperienceTM, The American Association for the Study of Liver Diseases Meeting.              

Summary of presented data

Single-doses of AB-729 studied to date, 60 mg, 90 mg and 180 mg, resulted in comparable mean HBsAg declines at week 12, followed by a sustained plateau phase. During the multiple-dose portion of the trial, 60 mg of AB-729 dosed every 4 weeks resulted in continuous declines in HBsAg, reaching a mean of –1.44 log10 IU/ML at week 16. Data beyond week 16 demonstrate further declines in HBsAg with no plateau seen to date. AB-729 also resulted in meaningful decreases in both HBV RNA and HBcrAg. AB-729 was generally safe and well tolerated. The presentation can be accessed through the Investors section under Events & Presentations of Arbutus' website at www.arbutusbio.com.

Repeat dosing of AB-729 60 mg every 4 weeks results in continuous HBsAg declines beyond week 12

  Mean (SE) Week 12
N=7
Mean (SE) Week 16
N=7
Mean (SE) Week 20
N=3
Δlog10 HBsAg (IU/mL) -1.10 (0.15) -1.44 (0.18) -1.73 (0.12)

Professor Yuen stated “These are the first multi-dose data for AB-729 and show continuous decline of HBsAg throughout the dosing period. Importantly, AB-729 was generally safe and well tolerated. These encouraging data support the continued development of AB-729 as a potential cornerstone of future combination regimens for the treatment of chronic hepatitis B infection.”

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 to 180 mg) of AB-729. An additional cohort in Part 2 included 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, are receiving multi-doses of AB-729 for up to six months.

About AB-729 

AB-729 is an RNA interference (RNAi) therapeutic targeted to hepatocytes using Arbutus’ novel covalently conjugated N-acetylgalactosamine (GalNAc) delivery technology that enables subcutaneous delivery. AB-729 inhibits viral replication and reduces all HBV antigens, including hepatitis B surface antigen in preclinical models. Reducing hepatitis B surface antigen is thought to be a key prerequisite to enable reawakening of a patient’s immune system to respond to the virus. In an ongoing single- and multi-dose Phase 1a/1b clinical trial, AB-729 demonstrated positive safety and tolerability data and meaningful reductions in hepatitis B surface antigen.

About HBV

Chronic hepatitis B virus (HBV) infection is a debilitating disease of the liver that afflicts over 250 million people worldwide with up to 90 million people in China, as estimated by the World Health Organization. HBV is a global epidemic that affects more people than hepatitis C virus (HCV) and HIV infection combined—with a higher morbidity and mortality rate. HBV is a leading cause of chronic liver disease and need for liver transplantation, and up to one million people worldwide die every year from HBV-related causes.

The current standard of care for patients with chronic HBV infection is life-long suppressive treatment with medications that reduce, but do not eliminate, the virus, resulting in very low cure rates. There is a significant unmet need for new therapies to treat HBV.

Conference Call and Webcast

Arbutus will hold a conference call and webcast on Monday, November 16, 2020 at 8:00 am Eastern Time to provide an AB-729 clinical update. You can access a live webcast of the call, which will include presentation slides, through the Investors section of Arbutus’ website at www.arbutusbio.com or directly at Live Webcast. Alternatively, you can dial (866) 393-1607 or (914) 495-8556 and reference conference ID 7791835.

An archived webcast will be available on the Arbutus website after the event. Alternatively, you may access a replay of the conference call by calling (855) 859-2056 or (404) 537-3406, and reference conference ID 7791835.

About Arbutus

Arbutus Biopharma Corporation is a publicly traded (Nasdaq: ABUS) biopharmaceutical company primarily dedicated to discovering, developing and commercializing a cure for people with chronic hepatitis B virus (HBV) infection. The Company is advancing multiple drug product candidates that may be combined into a potentially curative regimen for chronic HBV infection. Arbutus has also initiated a drug discovery and development effort for treating coronaviruses (including COVID-19). For more information, please visit www.arbutusbio.com.

SOURCE: Arbutus Biopharma

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