13 April 2021 - - US-based biopharmaceutical company VBI Vaccines Inc. (NASDAQ: VBIV) has released data and next steps from the high-dose cohort of its Phase 1b/2a clinical study of VBI-2601 (BRII-179), the company's hepatitis B immunotherapeutic candidate, in chronically-infected hepatitis B patients, the company said.

VBI-2601 (BRII-179) is being developed in collaboration with Brii Biosciences (Brii Bio) as part of a potential functional cure for chronic hepatitis B virus infection.

The Phase 1b/2a is a randomized, controlled study designed to assess the safety, tolerability, antiviral and immunologic activity of VBI-2601 (BRII-179) in 46 non-cirrhotic patients with chronic HBV infection on nucleos(t)ide analogue therapy.

The study is a two-part study to evaluate four doses of VBI-2601 (BRII-179), at either a low (20 µg) or high (40 µg) dose, with and without co-administration of interferon-alpha (IFN-α).

Data to-date from 33 evaluable patients across all study arms suggest VBI-2601 (BRII-179) was well-tolerated at all dose levels with and without IFN-α, with no significant adverse events identified; Restimulation of T cell immune responses to HBV surface antigens, including S, Pre-S1, and Pre-S2, in ≥ 50% (range: 50% - 78%) of evaluable patients from all VBI-2601 (BRII-179) cohorts compared to no detectable response in the control, NUC-only arm.

The T cell responses and antibody responses were comparable across the 20µg and 40µg unadjuvanted study arms.

T cell response rates between the adjuvanted and unadjuvanted cohorts were also comparable
VBI and Brii are targeting the presentation of the complete Phase 1b/2a dataset at a scientific conference later in 2021.

Based on the acceptable safety profile and vaccine-induced adaptive immune responses observed to-date, the high dose of VBI-2601 (BRII-179), both with and without IFN-α, was selected to progress into a Phase 2 combination study of VBI-2601 (BRII-179) and BRII-835 (VIR-2218), a novel small interfering ribonucleic acid (siRNA) therapeutic candidate designed to inhibit expression of HBV proteins.

Patient screening for the study initiated in March 2021 in New Zealand, and Brii Bio expects to initiate the study in China, Hong Kong, Australia, Taiwan, Singapore, Thailand, and South Korea in 2Q21 and 3Q21.