Durham, North Carolina, USA, and Beijing, China, November 6, 2026
Brii Biosciences (Brii Bio) has announced encouraging end-of-treatment and follow-up results from its Phase 2b ENRICH and ENHANCE clinical studies, highlighting the potential of its investigational hepatitis B immunotherapy candidate BRII-179 to improve functional cure rates in people living with chronic hepatitis B virus (HBV) infection. The findings were presented in three late-breaking scientific presentations at the American Association for the Study of Liver Diseases (AASLD) The Liver Meeting 2026, held in Denver, Colorado, from November 5–9, 2026. The research evaluated BRII-179 as an immune-priming treatment in combination with elebsiran, an investigational small interfering RNA (siRNA) therapy, and pegylated interferon alfa (PEG-IFNα). Across the studies, researchers observed encouraging rates of hepatitis B surface antigen (HBsAg) loss, an important biomarker associated with functional cure. In the Phase 2 ENRICH study, 41.9% of participants achieved HBsAg loss at the end of treatment, while 32.4% maintained HBsAg loss through 24 weeks after treatment. These findings support the potential of BRII-179 to stimulate HBV-specific immune responses and improve treatment outcomes, including among patients with higher baseline HBsAg levels, who can be particularly difficult to treat.
BRII-179 Strengthens Immune Priming in ENRICH Study
The Phase 2b ENRICH study evaluated sequential treatment with BRII-179, elebsiran and PEG-IFNα in adults with chronic HBV infection. BRII-179 is an investigational recombinant protein-based therapeutic vaccine designed to stimulate broad B-cell and T-cell immune responses against hepatitis B surface antigens. The treatment aims to strengthen the immune system’s ability to recognize and respond to HBV-infected cells. In the study, participants received BRII-179 as an initial immune-priming treatment before subsequent combination therapy with elebsiran and PEG-IFNα. Across the two treatment cohorts, 62 of 148 participants (41.9%) achieved HBsAg loss at the end of treatment, while 48 participants (32.4%) maintained this response 24 weeks after treatment completion. Importantly, among participants with baseline HBsAg levels above 1,000 IU/mL and up to 3,000 IU/mL, 20.8% maintained HBsAg loss at 24 weeks post-treatment. These results prospectively reproduced the immune-priming effect previously observed in the company’s ENSURE study. The findings suggest that strengthening HBV-specific immunity before introducing subsequent antiviral treatment may improve the likelihood of achieving sustained HBsAg loss.
ENHANCE Study Demonstrates Benefits of Combination Therapy
The Phase 2b ENHANCE study further investigated the combination of BRII-179, elebsiran and PEG-IFNα in adults with virologically suppressed chronic hepatitis B. In Part A1, participants receiving the triple combination achieved higher HBsAg loss rates than those receiving PEG-IFNα alone. At the end of treatment, the response rates were 25.5% compared with 10.2%, respectively. At 24 weeks after treatment completion, HBsAg loss remained higher in the triple-therapy group at 17.3%, compared with 6.1% in the monotherapy group. The research also evaluated a shortened treatment strategy in Part A2. Participants first received a 24-week priming phase with BRII-179 and elebsiran, followed by elebsiran and a shortened 24-week course of PEG-IFNα. This approach reduced the PEG-IFNα treatment duration by 50% compared with the 48-week regimen evaluated in Part A1. The Part A2 treatment group achieved an HBsAg loss rate of 22.5% at the end of treatment and 25.0% eight weeks after treatment completion. Researchers also observed that participants who developed an anti-HBs response during the priming phase had higher HBsAg loss rates than nonresponders. These findings provide additional evidence supporting the potential value of immune priming in combination-based HBV treatment strategies.
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Brii Bio Advances Its Functional Cure Strategy for HBV
The latest results strengthen Brii Bio’s clinical development strategy for achieving a functional cure for chronic hepatitis B. The company’s approach combines immune stimulation through BRII-179 with direct antiviral activity from elebsiran and additional immune modulation through PEG-IFNα. Elebsiran is an investigational HBV-targeting siRNA designed to reduce viral RNA transcripts and limit the production of hepatitis B surface antigen. By lowering viral antigen levels while strengthening immune responses, the combination aims to create conditions that support sustained HBsAg loss after treatment ends. Across the ENRICH and ENHANCE studies, the treatment regimens were generally safe and well tolerated, with adverse events largely consistent with the known safety profile of PEG-IFNα. Brii Bio plans to use the findings to guide future clinical research, particularly in patients with higher baseline HBsAg levels, where achieving functional cure remains challenging. Although the results are encouraging, HBsAg loss in these studies should be interpreted as a clinical marker of functional cure rather than proof of complete elimination of HBV from the body. Further research will be necessary to establish long-term durability, safety and clinical benefits. Overall, the Phase 2b findings represent an important milestone in Brii Bio’s efforts to develop combination therapies that could expand treatment possibilities for millions of people living with chronic hepatitis B.
Source: Brii Biosciences press release
