Arbutus Biopharma Corporation has reacquired global rights to its lead hepatitis B therapeutic imdusiran after mutually agreeing to conclude its strategic partnership with Qilu Pharmaceutical for Greater China markets. The move comes as the RNAi therapeutic has demonstrated functional cure in eight patients across two Phase 2a clinical trials.
The companies entered into their strategic partnership in 2021 for development, manufacturing and commercialization of imdusiran in mainland China, Hong Kong, Macau and Taiwan. Lindsay Androski, President and Chief Executive Officer of Arbutus, cited both companies' pipeline reprioritization efforts as the reason for the mutual decision to terminate the partnership.
"We are thrilled to once again hold global rights for imdusiran, which to date has achieved functional cure in eight patients in combination therapy in two Phase 2a trials," Androski stated.
Clinical Breakthrough in Hepatitis B Treatment
Across the IM-PROVE I and IM-PROVE II Phase 2a trials, imdusiran has enabled eight patients with chronic hepatitis B to achieve functional cure and discontinue all therapies, including nucleos(t)ide analogue therapy. Notably, two patients achieved functional cure without receiving interferon as part of their treatment regimen, while seven of the eight patients had baseline hepatitis B surface antigen levels below 1000 IU/mL.
The patients achieved functional cure following treatment with imdusiran and nucleos(t)ide analogue therapy in combination with either interferon or low-dose nivolumab plus an immunotherapeutic. Clinical data has shown imdusiran to be generally safe and well-tolerated while providing meaningful reductions in hepatitis B surface antigen and hepatitis B virus DNA.
Expert Advisory Board Formation
Concurrent with reacquiring global rights, Arbutus has launched a Scientific Advisory Board comprising five globally recognized leaders in chronic hepatitis B treatment with extensive late-stage clinical trial experience. The board will advise on strategic evaluation of the company's chronic hepatitis B pipeline.
The advisory board includes Jordan J. Feld from the University of Toronto and Toronto Centre for Liver Disease, Edward J. Gane from the University of Auckland who was involved in early development of the first oral hepatitis C cure, and Anna Suk-Fong Lok from the University of Michigan who has published over 600 scientific articles on hepatitis B. Mark Sulkowski from Johns Hopkins University School of Medicine has served as principal investigator for more than 200 viral hepatitis clinical trials, while Man-Fung Yuen from the University of Hong Kong has led most international trials examining novel chronic hepatitis B treatments.
RNAi Mechanism and Delivery Technology
Imdusiran is an RNAi therapeutic specifically designed to reduce all hepatitis B virus proteins and antigens, including hepatitis B surface antigen, which is considered a key prerequisite for reawakening a patient's immune system to control the virus. The therapeutic targets hepatocytes using Arbutus' novel covalently conjugated N-Acetylgalactosamine delivery technology, enabling subcutaneous administration.
Addressing Significant Unmet Medical Need
Chronic hepatitis B infection represents a substantial global health burden. The World Health Organization estimates over 250 million people worldwide suffer from chronic hepatitis B infection, with approximately 2 million people affected in the United States. Despite available vaccines and current treatment options, approximately 1.1 million people die annually from complications related to chronic hepatitis B infection.
The virus can cause chronic infection leading to higher risk of death from cirrhosis and liver cancer. Arbutus is developing imdusiran alongside an oral PD-1 inhibitor for chronic hepatitis B treatment as part of its infectious disease-focused pipeline.
