Chronic Hepatitis B Combo Competes Phase 2 Study

VBI Vaccines Inc. today announced interim data from the Phase 2 study evaluating the combination of VBI-2601 (BRII-179), VBI's HBV immunotherapeutic candidate, and BRII-835 (VIR-2218), an HBV-targeting siRNA candidate, in chronically infected HBV patients.

The data, which will be featured in an oral presentation on February 18, 2023, demonstrated that the combination therapy was generally well-tolerated, restored strong anti-HBsAg antibody responses, and led to improved HBsAg-specific T-cell responses when compared to BRII-835 alone.

Notably, in two participants who received the combination therapy, maximum reductions in HBsAg to an undetectable level or the lower limit of quantification (LLOQ) were achieved by Week 40, which were associated with robust HBV-specific antibody and T-cell responses.

Dr. Francisco Diaz-Mitoma, M.D., Ph.D., VBI's Chief Medical Officer, commented in a press release on February 15, 2023, "Numerous studies have assessed the potential of siRNA candidates in hundreds of chronically infected HBV patients, but this is the first time we've seen data from the combination of an HBV siRNA with an HBV-specific immunomodulatory."

"Consistent with the known mechanism of action of VBI-2601 and its inclusion of the pre-S1 and pre-S2 antigens in addition to the S antigen, these interim data indicate that VBI-2601 may be able to break tolerance to the S antigen, achieving immune restoration."

"Additionally, the reduction of S antigen to at or below the LLOQ, as seen in the two patients, is a noteworthy achievement in this population."

"We are very encouraged by these interim data, which suggest that the combination of VBI-2601 and an HBV siRNA has the potential to be a meaningful part of a functional cure regimen."

"We look forward to additional data from this study, as well as data from the ongoing Phase 2 study of VBI-2601 as an 'add-on' to existing pegylated interferon and nucleos(t)ide reverse transcriptase inhibitor therapy in non-cirrhotic chronic HBV patients, both of which are expected later this year."

An abstract summarizing the interim data is available at this link.