Arbutus Biopharma (NASDAQ:ABUS), a clinical-stage biopharmaceutical company specializing in chronic infectious diseases, announced today that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation for imdusiran (AB-729) for the treatment of chronic hepatitis B (cHBV).
Imdusiran is a subcutaneously delivered RNA interference (RNAi) therapeutic designed to suppress all HBV viral proteins and antigens, particularly the hepatitis B surface antigen (HBsAg), which is a critical step in reawakening a patient’s immune system to combat the virus.
The FDA’s Fast Track program is specifically intended to accelerate the development and review of drugs that treat serious conditions and fill unmet medical needs.
This designation provides Arbutus with opportunities for more frequent interactions with the FDA and potential eligibility for Accelerated Approval and Priority Review.
Lindsay Androski, President and CEO of Arbutus, noted that imdusiran has already achieved a "functional cure" in 10 patients across clinical trials, allowing them and several others to remain medication-free.
A functional cure in cHBV is defined as a sustained loss of HBsAg and undetectable HBV DNA after finishing a finite course of treatment.
Arbutus is currently positioning imdusiran as the cornerstone of a three-pronged combination strategy.
This approach aims to suppress viral DNA, reduce viral antigens, and boost the host's immune response.
Recent data from the IM-PROVE II Phase 2a trial—conducted in collaboration with Barinthus Biotherapeutics—showed that combining imdusiran with the immunotherapeutic VTP-300 and low-dose nivolumab led to significantly higher rates of HBsAg loss compared to previous cohorts.
As the company moves toward later-stage development, the Fast Track status will serve as a vital catalyst in streamlining the regulatory pathway for what could become a primary curative regimen for the millions of people living with cHBV worldwide