L-HBsAg

DURHAM, NC, USA and BEIJING, China I March 30, 2025 I Brii Biosciences Limited (“Brii Bio,” or the “Company”, stock code: 2137.HK), a biotechnology company developing therapies to improve patient health and choice across diseases with high unmet medical needs, announced new data from its ongoing Phase 2 ENSURE study as a late-breaking oral presentation at the 34 th Annual Meeting of Asian Pacific Association for the Study of the Liver (APASL 2025) in Beijing, China. ENSURE (NCT05970289) is a multicenter, open-label Phase 2 study. Cohorts 1-3 were designed to evaluate the contribution of elebsiran, an investigational small interfering ribonucleic acid (siRNA), in combination with pegylated interferon alpha (PEG-IFNα) in participants with chronic HBV infection with baseline hepatitis B surface antigen (HBsAg) of 100-3,000 IU/mL. Participants who completed 9 doses of BRII-179, a recombinant protein-based therapeutic vaccine, in combination with elebsiran (BRII-835) in a previous APAC study BRII-179-835-001 (NCT04749368) were enrolled to Cohort 4 of this study and received elebsiran and PEG-IFNα combination treatment. The design of Cohort 4 as part of this study was based on insight from previous studies that a significant proportion of the chronic HBV patients fail to generate a sufficient immune response after receiving multiple doses of BRII-179, and therefore unlikely to have the immune support to achieve sustainable functional cure. Emerging data from Cohort 4 showed that participants who previously had BRII-179 induced anti-HBs response achieved a substantially higher rate of HBsAg seroclearance than those who did not. At Week 24, more than half of the BRII-179 responders (55.6% [10/18]) achieved HBsAg seroclearance, compared to only 10.0% (1/10) in non-responders. These latest data suggest that BRII-179 can serve as a predictive tool for enriching patients more likely to respond to curative therapies. Additional data from Cohorts 1-3 of the ENSURE study showed that higher end of treatment (EOT) HBsAg loss and seroconversion rates in participants receiving elebsiran in combination with PEG-IFNα than those receiving PEG-IFNα alone. “The positive Cohort 4 data from the ENSURE study opens new doors for HBV functional cure,” said Dr. Grace Lai-Hung Wong, Professor of Gastroenterology and Hepatology at CUHK Medical Data Analytics Centre (MDAC) and Department of Medicine and Therapeutics in Hong Kong SAR, China. “Previous studies have suggested that BRII-179 may offer a unique opportunity to identify CHB patients who are able to elicit the necessary HBsAg antibody response. I believe these new findings provide clear evidence supporting such value proposition and further substantiate the role of BRII-179 in shaping future combination therapies.” “We are encouraged that the Cohort 4 from the ENSURE study continue to support our enrichment strategy in developing a functional cure for chronic HBV in target populations,” said David Margolis, MD, Chief Medical Officer of Brii Bio. “The results underscore the potential of BRII-179 in identifying patients who are more likely to respond to regimens aimed at functional cure, thereby enhancing functional cure rates in the target population while reducing exposure to costly therapies for those with a lower probability of cure. We are committed to advancing BRII-179 in combination with various modalities through our ongoing studies and collaborations with strategic partners, aiming to deliver higher functional cure rates to 254 million patients worldwide living with chronic HBV infection.” Abstract Number: OP0335 Presentation Title: Responders to Prior BRII-179 Treatment Achieved Faster and Higher Rate of HBsAg Seroclearance Following Treatment of Elebsiran and PEG-IFNα in Participants with Chronic Hepatitis B Virus Infection: Preliminary Data from ENSURE Study Presenter: Grace Lai-Hung Wong, MBChB (CUHK), MD (CUHK), FRCP (Lond, Edin), FHKCP, FHKAM (Medicine), Professor of Gastroenterology and Hepatology at CUHK Medical Data Analytics Centre (MDAC) and Department of Medicine and Therapeutics in Hong Kong SAR, China Abstract Number: LB0009 Presentation Title: Higher end of treatment (EOT) HBsAg loss and seroconversion rates in participants with chronic HBV infection receiving elebsiran (BRII-835) and pegylated interferon alfa-2a (PEG-IFNα) compared to PEG-IFNα alone: Week 48 results from ongoing ENSURE study Presenter: Jidong Jia, M.D., Ph.D., Professor of Medicine at the Liver Research Centre, Beijing Friendship Hospital, Capital Medical University in Beijing, China As part of Brii Bio’s unique approach to developing a functional cure for HBV, the Company and its partners are actively progressing multiple combination studies with our differentiated portfolio, including BRII-179, a recombinant protein-based HBV immunotherapeutic being evaluated in multiple combination studies with elebsiran led by Brii Bio; elebsiran being evaluated in combination with PEG-IFNα  in studies led by Brii Bio and tobevibart, an investigational broadly neutralizing monoclonal antibody targeting HBV, being evaluated  in multiple Phase 2 and 3 tobevibart and elebsiran combination studies led by Vir Biotechnology. Key data readouts will be shared in the coming months at the scientific conferences throughout 2025. About Hepatitis B Hepatitis B virus (HBV) infection is one of the world’s most significant infectious disease threats with more than 254 million people infected globally. [1] Chronic HBV infection is the leading cause of liver disease and an estimated 820,000 people die of complications from chronic HBV infection each year. [1] HBV is of exceptional concern in China, where 87 million people are chronically infected. [2] About BRII-179 BRII-179 is a novel recombinant protein-based HBV immunotherapeutic candidate that expresses the Pre-S1, Pre-S2, and S HBV surface antigens, and is designed to induce enhanced and broad B-cell and T-cell immunity. In November 2023, the Center for Drug Evaluation (the “CDE”) of the National Medical Products Administration (the “NMPA”) granted BRII-179 Breakthrough Therapy Designation. About Elebsiran (BRII-835, VIR-2218) Elebsiran is an investigational subcutaneously administered HBV-targeting siRNA designed to degrade hepatitis B virus RNA transcripts and limit the production of hepatitis B surface antigen. It has the potential to have direct antiviral activity against HBV and HDV. It is the first siRNA in the clinic to include Enhanced Stabilization Chemistry Plus technology to enhance stability and minimize off-target activity, which potentially can result in an increased therapeutic index. Brii Bio licensed exclusive rights to develop and commercialize elebsiran for the Greater China territory from Vir Biotechnology, Inc. in 2020. About Brii Bio Brii Biosciences Limited (“Brii Bio”, stock code: 2137.HK) is a biotechnology company developing therapies to address major public health challenges where patients experience high unmet medical needs, limited choice and significant social stigmas. With a focus on infectious diseases, the Company is advancing a broad pipeline of unique therapeutic candidates with lead programs against hepatitis B virus (HBV) infection. The Company is led by a visionary and experienced leadership team and has operations in key biotech hubs, including Raleigh-Durham, the San Francisco Bay Area, Beijing and Shanghai. For more information, visit www.briibio.com . SOURCE: Brii Biosciences

SAN FRANCISCO, CA, USA I March 13, 2025 I Vir Biotechnology, Inc. (Nasdaq: VIR) today announced the enrollment of the first patient in its Phase 3 ECLIPSE registrational program. The ECLIPSE registrational program is designed to evaluate the efficacy and safety of tobevibart in combination with elebsiran in people living with chronic hepatitis delta (CHD). ECLIPSE 1, the first trial of the program to be initiated, and ECLIPSE 2 are Phase 3 trials designed to provide the registrational data needed for submission to multiple regulatory agencies. ECLIPSE 3, a Phase 2b trial, is designed to provide important supportive data to help enable access and reimbursement strategies in key European markets. “The start of the ECLIPSE program marks a pivotal moment for patients living with hepatitis delta and for Vir Biotechnology. With a proven track record of developing treatments powering the immune system to transform lives this achievement is a testament to our ability to rapidly advance impactful treatments from discovery to patient care,” said Marianne De Backer, M.Sc., Ph.D., MBA, Chief Executive Officer, Vir Biotechnology. “The data from our SOLSTICE Phase 2 trial suggest that tobevibart and elebsiran can rapidly reduce hepatitis delta virus to undetectable levels, potentially driving important benefit for patients,” said Mark Eisner, M.D., M.P.H., Chief Medical Officer, Vir Biotechnology. “We are excited to further evaluate the potential of this combination in our Phase 3 program.” CHD is a debilitating inflammatory liver disease caused by the hepatitis delta virus (HDV). 1 It is the most severe form of chronic viral hepatitis 2 and on average, people living with CHD will progress to cirrhosis and liver failure within 5 years. 3 There is a high unmet medical need for effective treatments, as there are no approved therapies in the U.S., and options are limited in the European Union and globally. The objective of therapy is to eliminate the virus. Tobevibart in combination with elebsiran offers the potential to achieve this by tackling the viral lifecycle through multiple mechanisms. “Chronic hepatitis delta can be a devastating diagnosis, leaving all those impacted in the U.S. facing an uncertain future without approved treatment options,” said Chari A. Cohen, DrPH, M.P.H., President, Hepatitis B Foundation. “It is exciting to see potential new therapies for hepatitis delta, such as the combination of tobevibart and elebsiran, which could offer new hope to a community that has been waiting for efficacious treatment options for far too long.” The significant unmet need in CHD and the potential for tobevibart and elebsiran to provide a much-needed treatment option has been recognized by the U.S. Food and Drug Administration (FDA) with Breakthrough and Fast Track designations, and by the European Medicines Agency (EMA) Priority Medicines (PRIME) and orphan drug designation. About the ECLIPSE Registrational Program ECLIPSE is a Phase 3 registrational program to evaluate the safety and efficacy of tobevibart in combination with elebsiran in patients with chronic hepatitis delta. ECLIPSE includes three randomized, controlled trials designed to evaluate the combination therapy in comparison to deferred treatment or bulevirtide. ECLIPSE 1, the first trial of the program to be initiated, is a Phase 3 trial that will assess the efficacy and safety of tobevibart and elebsiran compared to deferred treatment in regions such as the U.S. where bulevirtide is not available or other regions where its access is limited. ECLIPSE 2 is a Phase 3 trial that will evaluate the efficacy and safety of switching to tobevibart and elebsiran in people with CHD who have not achieved viral suppression with bulevirtide therapy. ECLIPSE 1 and 2 are designed to provide the registrational efficacy and safety data needed for potential submission to global regulatory agencies. ECLIPSE 3 is a Phase 2b head-to-head trial to evaluate tobevibart and elebsiran compared with bulevirtide in bulevirtide-naïve patients, and it is designed to provide important supportive data to help establish access and reimbursement in key markets. ECLIPSE 1 plans to enroll 120 participants in the U.S. or other regions where bulevirtide use is limited. Participants will be randomized 2:1 to receive either tobevibart in combination with elebsiran or deferred treatment. During the deferred treatment period, participants will receive only nucleoside reverse transcriptase inhibitors (NRTIs). After the initial delay period, participants will be switched to the combination therapy of tobevibart and elebsiran. The composite primary endpoint measures HDV RNA at the lower limit of quantification target not detected or HDV RNA TND (defined as HDV RNA < 0 IU/mL) and ALT normalization at Week 48, compared to the deferred treatment group at the end of their deferred treatment period. About Tobevibart and Elebsiran Tobevibart is an investigational broadly neutralizing monoclonal antibody targeting the hepatitis B surface antigen (HBsAg). It is designed to inhibit the entry of hepatitis B and hepatitis delta viruses into hepatocytes and to reduce the level of circulating viral and subviral particles in the blood. Tobevibart was identified using Vir Biotechnology’s proprietary monoclonal antibody discovery platform. The Fc domain has been engineered to increase immune engagement and clearance of HBsAg immune complexes and incorporates Xencor’s Xtend™ technology to extend half-life. Tobevibart is administered subcutaneously, and it is currently in clinical development for the treatment of patients with chronic hepatitis delta and patients with chronic hepatitis B. Elebsiran is an investigational hepatitis B virus-targeting small interfering ribonucleic acid (siRNA) discovered by Alnylam Pharmaceuticals, Inc. It is designed to degrade hepatitis B virus RNA transcripts and limit the production of hepatitis B surface antigen. Current data indicates that it has the potential to have direct antiviral activity against hepatitis B virus and hepatitis delta virus. Elebsiran is administered subcutaneously, and it is currently in clinical development for the treatment of patients with chronic hepatitis delta and patients with chronic hepatitis B. About Vir Biotechnology, Inc. Vir Biotechnology, Inc., is a clinical-stage biopharmaceutical company focused on powering the immune system to transform lives by discovering and developing medicines for serious infectious diseases and cancer. Its clinical-stage portfolio includes infectious disease programs for chronic hepatitis delta and chronic hepatitis B infections and multiple dual-masked T-cell engagers across validated targets in solid tumor indications. Vir Biotechnology also has a preclinical portfolio of programs across a range of infectious diseases and oncologic malignancies. Vir Biotechnology routinely posts information that may be important to investors on its website. References: 1 NIH National Institute of Diabetes and Digestive and Kidney Diseases Hepatitis D – NIDDK (nih.gov) , accessed February 2025 2 WHO Hepatitis Delta Factsheet – Hepatitis D (who.int) , accessed February 2025 3 CDC What is Hepatitis D – FAQ | CDC , accessed February 2025 SOURCE: Vir Biotechnology

SAN FRANCISCO--( BUSINESS WIRE )--Vir Biotechnology, Inc. (Nasdaq: VIR) today announced that tobevibart and elebsiran have received U.S. Food and Drug Administration (FDA) Breakthrough Therapy designation and European Medicines Agency (EMA) Priority Medicines (PRIME) designation for the treatment of chronic hepatitis delta (CHD). The designations are supported by compelling positive safety and efficacy data from the Phase 2 SOLSTICE trial, from which the Company recently presented new data at AASLD The Liver Meeting ® in San Diego, U.S. Vir Biotechnology’s Phase 3 ECLIPSE registrational program evaluating tobevibart and elebsiran in CHD will commence in the first half of 2025. CHD is a chronic, progressive liver disease caused by the hepatitis delta virus 1 and is the most severe form of chronic viral hepatitis 2 . CHD increases the risk of liver cancer and accelerates progression to cirrhosis and liver failure, which often occurs within 5 years of infection 3 . There is no approved treatment in the U.S., and options are limited in the European Union and globally. “ Chronic hepatitis delta has devastating effects on liver and overall health, yet people living with this condition are still waiting for highly effective therapeutic options,” said Mark Eisner, M.D., M.P.H., Executive Vice President and Chief Medical Officer, Vir Biotechnology. “ The Phase 2 SOLSTICE trial data suggests that tobevibart and elebsiran can rapidly and deeply suppress the hepatitis delta virus, driving it to undetectable levels. Receiving FDA Breakthrough Therapy and European PRIME designations recognizes this combination’s potential to transform the lives of people living with CHD. We look forward to advancing the Phase 3 ECLIPSE program as quickly as possible.” FDA Breakthrough Therapy designation aims to expedite the development and regulatory reviews of investigational therapies for serious conditions that demonstrate promising preliminary clinical evidence and potential improvement over existing therapies. EMA PRIME designation is granted to investigational medicines that target conditions with unmet medical needs for which no treatment option exists, or where they can offer a major therapeutic advantage over existing treatments. It fosters early exchange with the EMA to facilitate robust data collection, high-quality marketing authorization applications and expedited evaluations so that medicines can reach patients earlier. These designations follow FDA Fast Track designation and EMA Committee for Orphan Medicinal Products (COMP) positive opinion on orphan drug designation received earlier this year. About the Phase 2 SOLSTICE Trial SOLSTICE is a Phase 2 study to evaluate the safety, tolerability, and efficacy of tobevibart, alone or in combination with elebsiran, in patients with chronic hepatitis delta. This Phase 2 study is a multi-center, open-label, randomized study. Primary endpoints include proportion of participants with undetectable hepatitis delta virus (HDV) RNA (defined as HDV RNA equal or greater than 2 log 10 decrease from baseline or below limit of detection) up to week 24, alanine aminotransferase (ALT) normalization (defined as ALT below upper limit of normal) up to week 24, and treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs) up to 118 weeks. Secondary endpoints include proportion of participants with undetectable HDV RNA and different timepoints and up to 192 weeks. More information about this trial can be found at clinicaltrials.gov (NCT05461170). About Tobevibart and Elebsiran Tobevibart is an investigational broadly neutralizing monoclonal antibody targeting the hepatitis B surface antigen. It is designed to inhibit the entry of hepatitis B and hepatitis delta viruses into hepatocytes, and to reduce the level of circulating viral and subviral particles in the blood. Tobevibart, which incorporates Xencor’s Xtend™ and other Fc technologies, has been engineered to have an extended half-life and was identified using Vir Biotechnology’s proprietary monoclonal antibody discovery platform. Tobevibart is administered subcutaneously, and it is currently in clinical development for the treatment of patients with chronic hepatitis B and patients with chronic hepatitis delta. Elebsiran is an investigational hepatitis B virus-targeting small interfering ribonucleic acid (siRNA) designed to degrade hepatitis B virus RNA transcripts and limit the production of hepatitis B surface antigen. Current data indicates that it has the potential to have direct antiviral activity against hepatitis B virus and hepatitis delta virus. Elebsiran is administered subcutaneously, and it is currently in clinical development for the treatment of patients with chronic hepatitis B and patients with chronic hepatitis delta. It is the first asset in Vir Biotechnology’s collaboration with Alnylam Pharmaceuticals, Inc. to enter clinical studies. About Vir Biotechnology, Inc. Vir Biotechnology, Inc. is a clinical-stage biopharmaceutical company focused on powering the immune system to transform lives by discovering and developing medicines for serious infectious diseases and cancer. Its clinical-stage portfolio includes infectious disease programs for chronic hepatitis delta and chronic hepatitis B infections and multiple double-masked T-cell engagers across validated targets in solid tumor indications. Vir Biotechnology also has a preclinical portfolio of programs across a range of infectious diseases and oncologic malignancies. Vir Biotechnology routinely posts information that may be important to investors on its website. References: 1 NIH National Institute of Diabetes and Digestive and Kidney Diseases Hepatitis D - NIDDK (nih.gov) , accessed September 2024. 2 WHO Hepatitis Delta Factsheet - Hepatitis D (who.int) , accessed September 2024. 3 CDC What is Hepatitis D - FAQ | CDC . Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “plan,” “potential,” “aim,” “expect,” “anticipate,” “promising” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Vir Biotechnology’s expectations and assumptions as of the date of this press release. Forward-looking statements contained in this press release include, but are not limited to, statements regarding Vir Biotechnology’s strategy and plans, the potential clinical effects of tobevibart and elebsiran, the potential benefits, safety and efficacy of tobevibart and elebsiran, the timing, nature and significance of data from Vir Biotechnology’s multiple ongoing trials evaluating tobevibart and elebsiran, Vir Biotechnology’s plans and expectations for its CHD and CHB programs, and risks and uncertainties associated with drug development and commercialization. Many factors may cause differences between current expectations and actual results, including unexpected safety or efficacy data or results observed during clinical trials or in data readouts; the occurrence of adverse safety events; risks of unexpected costs, delays or other unexpected hurdles; difficulties in collaborating with other companies; successful development and/or commercialization of alternative product candidates by Vir Biotechnology’s competitors; changes in expected or existing competition; delays in or disruptions to Vir Biotechnology’s business or clinical trials due to geopolitical changes or other external factors; and unexpected litigation or other disputes. Drug development and commercialization involve a high degree of risk, and only a small number of research and development programs result in commercialization of a product. Results in early-stage clinical trials may not be indicative of full results or results from later stage or larger scale clinical trials and do not ensure regulatory approval. You should not place undue reliance on these statements, or the scientific data presented. Other factors that may cause actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Vir Biotechnology’s filings with the U.S. Securities and Exchange Commission, including the section titled “Risk Factors” contained therein. Except as required by law, Vir Biotechnology assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.