FDA lifts clinical hold on Arbutus's AB-101 IND application

Arbutus Biopharma Corporation announced on October 22, 2026 that the FDA notified the company that the clinical hold on the Investigational New Drug application for AB-101 has been removed and that the company may engage in additional clinical development for AB-101 in the United States.¹ The company said it is evaluating next steps for the continued development of AB-101.¹

AB-101 is described as a proprietary oral PD-L1 inhibitor that has the potential to activate patients' hepatitis B virus-specific immune response by inhibiting PD-L1.¹ The drug has completed a Phase 1a/1b clinical trial (AB-101-001) evaluating safety, tolerability, pharmacokinetics, and pharmacodynamics of single- and multiple-ascending oral doses in healthy subjects and patients with chronic HBV infection.¹

According to the release, data from healthy subjects in Parts 1 and 2 and cHBV patients in Part 3 of the trial showed AB-101 was generally well-tolerated, with evidence of high receptor occupancy in seven cHBV patients and hepatitis B surface antigen decline in two cHBV patients at the 30mg dose.¹

Arbutus is a clinical-stage biopharmaceutical company, and the release states it is currently developing imdusiran (AB-729) and an oral PD-L1 inhibitor (AB-101) for the treatment of cHBV infection.¹ The company also noted its involvement with its exclusive licensee, Genevant Sciences, to protect and defend its intellectual property, which is the subject of on-going lawsuits against Pfizer Inc., BioNTech SE, and certain of their affiliates, for use of Arbutus' patented LNP technology in their COVID-19 vaccines.¹

The filing with the SEC confirms that on October 22, 2026, Arbutus issued the press release announcing that the FDA has lifted the clinical hold on the IND application for AB-101, the company's oral PD-L1 inhibitor.¹