Benzinga | Dec 1, 2021 12:01PM EST

Arbutus Reports Prelim. Data On Co.'s Capsid Inhibitor AB-836 Is Generally Safe, Well Tolerated, Provides Antiviral Activity

Arbutus Biopharma Corporation (NASDAQ:ABUS), a clinical-stage biopharmaceutical company primarily focused on discovering, developing and commercializing a broad portfolio of assets with different modes of action to provide a cure for people with chronic hepatitis B virus (cHBV) infection and to treat coronaviruses (including COVID-19), today announced preliminary data from its on-going Phase 1a/1b clinical trial demonstrating that its next generation capsid inhibitor, AB-836, is generally safe and well-tolerated in both healthy subjects and patients with cHBV and provides robust antiviral activity.

Gaston Picchio, Ph.D., Chief Development Officer at Arbutus, commented, "These preliminary results demonstrate that AB-836 is generally safe and well-tolerated in both single- and multiple-doses in healthy subjects and at doses up to 100mg administered once daily for 28 days in cHBV patients. In addition, the mean Day 28 drop in HBV DNA observed to date with a relatively low dose suggests that AB-836 is a very potent inhibitor of HBV replication making it an ideal candidate to potentially completely suppress viral replication. We look forward to continuing to evaluate the safety and efficacy of AB-836 in Part 3 of this trial."

The Phase 1a/1b clinical trial is designed to evaluate the safety, tolerability, pharmacokinetics and antiviral activity of single and multiple doses of AB-836 in healthy subjects and patients with cHBV. The trial consists of three parts. Part 1 evaluated alternating single doses of AB-836 or placebo ranging from 10mg to 175mg in a fasted or fed state in healthy subjects. Part 2 evaluated multiple ascending doses of 50mg, 100mg or 150mg of AB-836 or placebo once daily for 10 days in healthy volunteers. Part 3, which is still on-going, is currently randomizing HBV DNA positive cHBV patients who are HBeAg positive or negative to receive either 50mg or 100mg of AB-836 or placebo once daily for 28 days.

In Parts 1 and 2, a total of 47 healthy subjects were enrolled and dosed. There were no deaths or serious adverse events (SAEs) observed. One healthy subject that received 50mg once daily discontinued after treatment on day 13 due to an adverse event (AE) of agitation. All but three AEs were mild (Grade 2 headache, agitation and bronchitis), and only one was assessed as related to AB-836 (Grade 1 rash). There were no clinically significant abnormalities in clinical laboratory tests, ECGs, vital signs or physical exams noted.

In Part 3, 16 cHBV patients have been dosed thus far with enrollment continuing. Among those who received 100mg once daily for the full 28 days (n=4), robust antiviral activity was observed at Day 28 of treatment with a mean (SE) log10 change from baseline of -3.1 (0.5). There have been no deaths or AEs. One cHBV patient that received 100mg of AB-836 had a transient increase in ALT from baseline Grade 1 to Grade 3 at a single visit that resolved with continued dosing and had no associated symptoms. There were no clinically significant abnormalities in ECGs, vital signs or physical exams noted.

Arbutus is continuing to enroll and dose cHBV patients in Part 3 of the clinical trial and anticipates presenting additional data at a medical conference in 2022.