– Participants who achieved hepatitis B surface antigen (HBsAg) clearance after receiving pegylated interferon alfa (PEG-IFNα) monotherapy or in combination with elebsiran or BRII-179 showed favorable post-treatment clinical outcomes: most HBsAg rebounds were below 10 IU/mL, HBV DNA rebounds were rare, and no clinically significant alanine aminotransferase (ALT) elevations were observed, suggesting durable immunological control after treatment cessation, supporting the safe discontinuation of nucleos(t)ide reverse transcriptase inhibitors (NRTIs) in regimens combining PEG-IFNα with novel therapeutic agents.
– Shortening the NRTI consolidation treatment period did not increase the incidence of HBsAg rebound, indicating the feasibility of reducing or even omitting the NRTI consolidation phase in such combination treatment regimens.
Beijing, China and Durham, North Carolina, USAApril 26, 2026 /PRNewswire/ — Brii Biosciences Limited (“Brii Biosciences” or the “Company,” stock code: 2137.HK), a biotechnology company dedicated to developing therapies to improve patient health outcomes and treatment options for diseases with significant unmet medical needs, presented a cross-study pooled analysis of post-treatment HBsAg rebound characteristics at the 35th Annual Meeting of the Asian Pacific Association for the Study of the Liver (APASL), held from April 22 to 25, 2026, in Istanbul, Turkey.
This analysis evaluated HBsAg rebound in NRTI-treated participants with chronic hepatitis B virus (HBV) infection who achieved HBsAg clearance in two Phase II studies, ENSURE and BRII-179-002, following the end of treatment (EOT). ENSURE is a Phase II study designed to evaluate the safety and efficacy of combination treatment strategies in improving functional cure for hepatitis B. Cohorts 1–3 compared the therapeutic effects of elebsiran combined with PEG-IFNα versus PEG-IFNα monotherapy; Cohort 4 assessed the potential role of BRII-179 in screening immunologically responsive populations and enhancing HBsAg clearance rates. BRII-179-002 is a multicenter, randomized, double-blind Phase II proof-of-concept study evaluating the combination of BRII-179 added to PEG-IFNα therapy.
This analysis pooled data from both studies to assess the incidence, magnitude, and clinical relevance of HBsAg rebound in participants treated with PEG-IFNα monotherapy or in combination with elebsiran or BRII-179 after EOT. The pooled analysis showed favorable overall clinical outcomes after treatment cessation: all HBsAg rebound levels were below 100 IU/mL, with the majority below 10 IU/mL. Following NRTI discontinuation, the incidence of HBV DNA rebound was low, and no clinically significant ALT elevations associated with NRTI cessation were observed. Overall, these results indicate that participants achieved durable immunological control after treatment cessation, further supporting the feasibility of safely discontinuing NRTIs in PEG-IFNα-based regimens combined with novel therapeutic agents. Notably, a shorter NRTI consolidation period (12–20 weeks) did not increase the incidence of HBsAg rebound compared to a 24-week NRTI consolidation period, suggesting that reducing or even omitting the NRTI consolidation phase is feasible in future treatment strategies.
Dr. David Margolis, Chief Medical Officer of Brii Biosciences, stated: “We are encouraged by these accumulating data, demonstrating that our novel combination treatment regimens can not only achieve rapid HBsAg clearance but also maintain durable immunological control after treatment cessation. These findings further strengthen our confidence in BRII-179 and elebsiran as key components of next-generation hepatitis B cure strategies. We look forward to additional data from ongoing studies throughout 2026.”
Additional details of the oral presentation are as follows:
Title: Cross-Study Pooled Analysis of HBsAg Rebound Following Treatment with Elebsiran/BRII-179 in Combination with Pegylated Interferon Alfa
Session/Presentation Format: Oral Presentation (Session 58)
Date and Time: April 25, 2026, 13:40–15:10 (UTC+3)
Presenter: Professor Jia Jidong, MD, PhD, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing
- Among 55 participants, 24 (43.6%) experienced HBsAg rebound after EOT; the rebound rate during NRTI consolidation was 23.6% (13/55), and after NRTI discontinuation was 26.8% (11/41), which were comparable.
- Up to 24 weeks after NRTI discontinuation, participants receiving 12–20 weeks of consolidation (rebound rate 15.0% [3/20]) did not show an increased incidence of HBsAg rebound compared to those receiving 24 weeks of NRTI consolidation (rebound rate 23.8% [5/21]).
- The magnitude of HBsAg rebound was generally limited, with all rebounds below 100 IU/mL, and 75.0% (18/24) of participants remained below 10 IU/mL. After NRTI discontinuation, HBV DNA rebound was rare, with over 90% (38/41) of participants having HBV DNA below the lower limit of quantification (LLOQ) at the last evaluable follow-up. No rapid ALT elevations were observed; only one participant had ALT exceeding the normal range, and the investigator reinitiated NRTI therapy based on clinical judgment.
About Hepatitis B
Hepatitis B virus (HBV) infection is one of the world’s most significant infectious disease threats, affecting over 254 million people globally.[1] Chronic HBV infection is a leading cause of liver disease, resulting in approximately 820,000 deaths annually from complications of chronic HBV infection.[1] In China, chronic HBV infection affects 87 million people, a matter of significant concern.[2]
About BRII-179
BRII-179 is a novel recombinant protein-based HBV immunotherapeutic candidate that expresses HBV Pre-S1, Pre-S2, and S surface antigens, designed to induce enhanced and broad B-cell and T-cell immune responses. In November 2023, the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) granted BRII-179 breakthrough therapy designation.
About Elebsiran
Elebsiran is an investigational subcutaneously administered small interfering ribonucleic acid (siRNA) targeting hepatitis B virus (HBV), designed to degrade HBV RNA transcripts and limit the production of hepatitis B surface antigen, with direct antiviral activity against HBV and hepatitis delta virus (HDV). It is the first siRNA to enter clinical development using enhanced stabilization chemistry to increase stability and minimize off-target activity, potentially improving the therapeutic index. Brii Biosciences obtained exclusive rights to develop and commercialize elebsiran in Greater China from Vir Biotechnology, Inc. in 2020. In May 2024, the Center for Drug Evaluation (CDE) of China’s National Medical Products Administration (NMPA) granted elebsiran breakthrough therapy designation.
About Brii Biosciences
Brii Biosciences (stock code: 2137.HK) is a biotechnology company dedicated to developing therapies to improve patient health outcomes in areas with significant unmet patient needs and limited treatment options. The Company is advancing a unique pipeline of drug candidates, including its most advanced programs targeting hepatitis B virus (HBV) infection. Led by a visionary and experienced leadership team, the Company operates in both China and the United States. For more information, please visit www.briibio.com.
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[2] World Health Organization. Hepatitis. World Health Organization. Retrieved from https://www.who.int/china/health-topics/hepatitis#:~:text=There%20are%2087%20million%20people,living%20with%20chronic%20hepatitis%20C. |