DURHAM, N.C. and BEIJING, China, May 27, 2026
Brii Biosciences Limited (Brii Bio) has presented new late-breaking clinical and translational data from its Phase 2 ENSURE study at the European Association for the Study of the Liver (EASL) Congress 2026 in Barcelona, further strengthening the company’s strategy to achieve a functional cure for chronic hepatitis B virus (HBV) infection. The results highlighted the potential role of the company’s investigational therapeutic vaccine BRII-179 in combination with the siRNA therapy elebsiran and pegylated interferon alfa (PEG-IFNα) to deliver durable immunological control of HBV.
According to Brii Bio, the final data from the ENSURE study demonstrated that the addition of elebsiran to PEG-IFNα therapy produced higher functional cure rates compared with PEG-IFNα treatment alone. The findings were especially encouraging among participants previously treated with BRII-179, where the highest rates of sustained hepatitis B surface antigen (HBsAg) loss were observed. Researchers stated that the results support the hypothesis that immune priming with BRII-179 may significantly improve responsiveness to curative HBV treatment strategies and potentially contribute to long-term immune control of the virus.
ENSURE Study Highlights Improved Functional Cure Rates
The multicenter, open-label ENSURE Phase 2 study enrolled patients across the Asia-Pacific region and evaluated multiple treatment combinations targeting chronic HBV infection. Cohorts 1 through 3 investigated the contribution of elebsiran, an investigational HBV-targeting small interfering RNA (siRNA), in combination with PEG-IFNα. Cohort 4 evaluated a novel sequential treatment strategy involving prior BRII-179 exposure followed by combination treatment with elebsiran and PEG-IFNα.
Final results showed that patients receiving elebsiran plus PEG-IFNα achieved higher functional cure rates compared with PEG-IFNα alone. Functional cure was defined as sustained HBsAg loss with undetectable HBV DNA maintained for at least 24 weeks after discontinuation of all therapy, including nucleos(t)ide analogues. In Cohort 4, BRII-179-experienced participants achieved particularly strong outcomes, with anti-HBs responders demonstrating the highest functional cure rates among all study groups.
Advertisement
The study also reported encouraging safety findings. Researchers observed no new treatment-related adverse events following discontinuation of nucleos(t)ide analogues, while most treatment-related adverse events resolved during post-treatment follow-up. Participants achieving sustained HBsAg loss also demonstrated favorable long-term outcomes characterized by infrequent HBV DNA rebound and no clinically significant alanine aminotransferase (ALT) elevations.
Dr. David Margolis, Chief Medical Officer of Brii Bio, stated that the consistency of the ENSURE findings reinforces the therapeutic potential of BRII-179 and elebsiran in improving functional cure outcomes for chronic HBV patients. He noted that the data provide important scientific guidance for future development of the company’s HBV functional cure programs.
Translational Data Reveal Potential Immune Mechanisms
In addition to the clinical findings, Brii Bio also presented new translational research offering insights into the potential immune mechanisms underlying BRII-179 activity. Researchers identified vaccine-induced CD4+ T-cell responses targeting mismatched HBV epitope sequences within the Pre-S1 region. These immune responses remained functionally stable for more than two years and persisted during subsequent combination treatment with PEG-IFNα and elebsiran.
The translational study further demonstrated that BRII-179-induced T-cell responses were associated with progressive maturation of HBs-specific B cells, an effect linked to enhanced HBsAg loss rates during therapy. Scientists believe these findings provide important mechanistic evidence supporting the ability of BRII-179 to prime HBV-specific immunity and potentially improve the durability of functional cure outcomes.
BRII-179 is a recombinant protein-based HBV immunotherapeutic candidate designed to induce broad B-cell and T-cell immune responses targeting HBV surface antigens. The therapy previously received Breakthrough Therapy Designation from China’s National Medical Products Administration (NMPA) Center for Drug Evaluation in 2023. Elebsiran, the company’s investigational siRNA therapy, also received Breakthrough Therapy Designation from Chinese regulators in 2024.
Brii Bio Expands Global HBV Cure Development Programs
Brii Bio confirmed that additional clinical development programs are already underway to further optimize combination treatment regimens and define the role of BRII-179 in future pivotal HBV studies. The company is currently conducting the ENRICH and ENHANCE Phase 2b trials, which are evaluating both concurrent and sequential combination approaches involving BRII-179, elebsiran, and PEG-IFNα. End-of-treatment data from these studies are expected later in 2026.
Chronic hepatitis B remains one of the world’s most serious infectious diseases, affecting more than 254 million people globally and causing an estimated 820,000 deaths annually due to liver-related complications. The disease burden remains especially significant in China, where approximately 87 million people are chronically infected with HBV. Industry analysts believe therapies capable of delivering durable functional cures could significantly transform the global HBV treatment landscape over the coming decade.
Source: Brii Bio press release
