Arbutus' hepatitis B drug shows Phase 2 promise
- New data from a mid-stage study of Arbutus Biopharma Corp.'s hepatitis B treatment appear to support a bi-weekly treatment regimen for the RNA interference therapeutic.
- Results from "Cohort 4" of Arbutus' Phase 2 trial of ARB-1467 showed bi-weekly dosing reduced serum HBsAg levels in all 12 patients, with a greater average reduction than that seen from a monthly dosing regimen in the previous three cohorts of the study.
- Detailed results will be presented at a medical meeting in October, and the data will help Arbutus conduct a longer-term study testing ARB-1467 in combination with tenofovir, followed by interferon treatment.
More than 250 million people worldwide live with hepatitis B virus infection, leading to nearly 900,000 deaths each year — mostly from complications like liver cirrhosis and cancer. While breakthroughs in chronic hepatitis C infection have meant near cures for many patients with that disease, there is still a substantial unmet need for better treatments for patients with hepatitis B.
"The new Phase II results for ARB-1467 show greater reduction in serum HBsAg levels with a favorable safety profile," said Mark Murray, Arbutus’ CEO. "The design of the [new] study is informed by the findings in Cohort 4 and has the potential to create a late stage development and possible approval pathway for ARB-1467."
Arbutus plans to initiate that study sometime in the fourth quarter of this year.
RNAi therapeutics — drugs which act by "silencing" genes that encode for disease-causing proteins — have drawn interest for years. Until earlier this month, though, no RNAi drug had made it through Phase 3 with positive results. The success of Alnylam Pharmaceuticals, Inc.'s patisiran has changed that narrative, and put the RNAi field on the cusp of breaking through to market.
Alnylam's trial win also had the knock-on effect of boosting Arbutus' share — due to both Arbutus' work in RNAi and because Alnylam's drug uses a delivery system licensed from Arbutus. (Arbutus was previously known as Tekmira before rebranding following the merger with OnCore.)
Both Alnylam's patisiran and Arbutus' ARB-1467 use Arbutus' lipid nanoparticle technology to reach target cells. If patisiran is approved, Arbutus would net single-digit royalties, helping offset lost potential revenue when Alexion Pharmaceuticals, Inc. nixed a partnership earlier this year.
- Arbutus Biopharma Press release
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