Company: ABUS
Filing Date: 2025-05-14
Form Type: 10-Q
Source: 0001447028-25-000099
Chunk: 43

Company: Arbutus Biopharma Corp
Filing Date: 2025-05-14
Form: 10-Q
Item: Part I, Item 1
Chunk 43
---
 2025, Barinthus announced a shift in its 

23

strategic business focus that included postponing further development of VTP-300 after its ongoing VTP-300 clinical trials have concluded. The parties do not intend to undertake a larger Phase 2b with this combination treatment regimen.  

Oral PD-L1 Inhibitor (AB-101)

PD-L1 inhibitors complement our pipeline of agents and could potentially be an important part of a combination therapy for the treatment of HBV by reawakening the immune system. Highly functional HBV-specific T-cells within our immune system are believed to be required for long-term HBV viral resolution. However, HBV-specific T-cells become functionally defective, and greatly reduced in number during cHBV infection. One approach to boost HBV-specific T-cells is to prevent PD-L1 proteins from binding to PD-1, which would otherwise lead to inhibition of the HBV-specific immune function of T-cells. 

AB-101 is our proprietary oral small-molecule PD-L1 inhibitor candidate that we believe will allow for controlled checkpoint blockade while minimizing the systemic safety issues often seen with checkpoint inhibitor antibody therapies.  AB-101 is differentiated from monoclonal antibody checkpoint inhibitors such as durvalumab (anti-PD-L1) and nivolumab (anti-PD-1) because it is liver centric, has a much shorter duration of effect in preclinical models (which may provide dosing and safety advantages), and has a novel mechanism of action as it binds to PD-L1 on the surface of cells causing dimerization, internalization and degradation of the PD-L1 protein. 

Phase 1a/1b clinical trial to evaluate safety, tolerability and PK/PD of AB-101 (AB-101-001)

AB-101-001 is a Phase 1a/1b clinical trial designed to investigate the safety, tolerability and PK/PD of single and multiple-ascending oral doses of AB-101 for up to 28 days in healthy subjects and patients with cHBV infection. The trial consists of three parts starting with single ascending doses in healthy subjects, followed by multiple ascending doses in healthy subjects and culminating with multiple doses in patients with cHBV infection. Safety and PK/PD assessments are performed prior to dose escalation in all parts of the clinical trial. 

Part 1 of this clinical trial enrolled five sequential cohorts of eight healthy subjects each (6 active: 2