Arbutus Biopharma Corporation announced that the first patient has been dosed in the additional treatment arm of the AB-729 Phase 2a triple combination clinical trial that has been expanded to include a PD-1 monoclonal antibody, nivolumab. Nivolumab is approved for a number of types of cancer under the brand name, Opdivo®?. AB-729 was specifically designed to reduce all HBV viral proteins and antigens, including hepatitis B surface antigen, which is thought to be a key prerequisite to enable reawakening of a patient's immune system to respond to the virus.

The Phase 2a triple combination clinical trials, AB-729-202, has been expanded to evaluate the safety, antiviral activity and immunogenicity of nivolumab plus Vaccitech's VTP-300, an antigen-specific antigen encoding multiple hepatitis B antigens, following treatment with AB-729 and ongoing NA therapy. Approximately 20 virologically-suppressed chronic hepatitis B (cHBV) patients will be enrolled in the open-label arm to receive AB-729 (60mg every 8 weeks) plus NA therapy for 24 weeks. At week 48, all patients will be evaluated for eligibility to discontinue their NA therapy.

Enrollment is complete in the original portion of the clinical trial, which is currently evaluating the triple combination of AB-729, NA therapy and VTP-300 or placebo. Preliminary data from the original portion of the trial is expected in the second half of 2023. Clinical data generated thus far has shown single- and multi-doses of AB-729 to be generally safe and well-tolerated while providing meaningful reductions in hepatitis B surface antigen and hepatitis B DNA.

AB-729 is currently in multiple Phase 2a clinical trials. Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). HBV can cause chronic infection which leads to a higher risk of death from cirrhosis and liver cancer.

Chronic HBV infection represents a significant unmet medical need. The World Health Organization estimates that over 290 million people worldwide suffer from chronic HBV infection, while other estimates indicate that approximately 2.4 million people in the United States suffer from chronic HBV infection. Approximately 820,000 people die every year from complications related to chronic HBV infection despite the availability of effective vaccines and current treatment options.