RegulationBreakthrough Therapy (United States), Fast Track (United States), Orphan Drug (European Union), PRIME (European Union), Breakthrough Therapy (China)

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Clinical Trials associated with Elebsiran

NCT07142811

/ RecruitingPhase 2

A Phase 2b Randomized, Open-Label Study to Evaluate the Efficacy and Safety of Tobevibart+Elebsiran Combination Therapy Versus Bulevirtide in Participants With Chronic HDV Infection (ECLIPSE 3)

A Study to Evaluate Tobevibart+Elebsiran versus Bulevirtide in Chronic HDV Infection

Start Date05 Aug 2025

Sponsor / Collaborator

Vir Biotechnology, Inc.

NCT07128550

/ RecruitingPhase 3

A Phase 3 Randomized, Open-Label Study to Evaluate the Efficacy and Safety of Tobevibart+Elebsiran Combination Therapy in Participants With Chronic HDV Infection Not Virologically Suppressed With Bulevirtide (ECLIPSE 2)

This is a multicenter, open label, randomized Phase 3 clinical study to evaluate tobevibart + elebsiran in participants with Chronic HDV Infection not virologically suppressed with bulevirtide

Start Date30 Jul 2025

Sponsor / Collaborator

Vir Biotechnology, Inc.

ACTRN12625000416493

/ Not yet recruitingPhase 3

A Phase 3 Randomized, Open-Label Study to Evaluate the Efficacy and Safety of Tobevibart+Elebsiran Combination Therapy in Participants with Chronic HDV Infection (ECLIPSE 1)

Start Date29 May 2025

Sponsor / Collaborator

Vir Biotechnology, Inc.

100 Clinical Results associated with Elebsiran

100 Translational Medicine associated with Elebsiran

100 Patents (Medical) associated with Elebsiran

Literatures (Medical) associated with Elebsiran

01 Jul 2025·GASTROENTEROLOGY

The Impact of Hepatitis B Surface Antigen Reduction via Small Interfering RNA Treatment on Natural and Vaccine (BRII-179)-Induced Hepatitis B Virus-Specific Humoral and Cellular Immune Responses

Article

Author: Tan, Ying ; Ma, Haiyan ; Lee, Ariel ; Bertoletti, Antonio ; Chen, Jieliang ; Wang, Bing ; Zhu, Chong ; Douglas, Mark W ; Lai-Hung Wong, Grace ; Li, Dong ; Chen, Xiaofei ; Ji, Yun ; Yuen, Man-Fung ; Lv, Jianxiang ; Zhu, Qing ; Le Bert, Nina

BACKGROUND & AIMS:

The impact of hepatitis B surface antigen (HBsAg) reduction from small interfering RNA (siRNA) treatments on hepatitis B virus (HBV)-specific immunity of individuals with chronic hepatitis B (CHB) has not been adequately analyzed in humans. We conducted a phase 2a study treating CHB participants with nine 4-weekly doses of HBV-targeted siRNA elebsiran (BRII-835), either alone (n = 10) or in combination with a virus-like particle-based therapeutic vaccine (BRII-179) containing Pre-S1, Pre-S2, and S antigens, coadministered with (n = 39) or without (n = 41) interferon alfa.

METHODS:

We analyzed longitudinally for 72 weeks virologic, clinical, and immunologic parameters, including HBsAg, alanine aminotransferase, hepatitis B surface antibody (anti-HBs), the neutralizing activity of representative sera, and frequency and cytokine secretion ability of T cells specific for Pre-S1, Pre-S2, and S both directly ex vivo and after in vitro expansion.

RESULTS:

Combination therapy with elebsiran and BRII-179 was well tolerated. Although no sustained HBsAg seroclearance or notable difference in mean HBsAg reduction at the group level was observed, we detected marked heterogeneity in immunologic responses among groups. HBsAg reduction mediated by siRNA alone was associated with minimal HBV-specific immune response recovery. In contrast, combination of elebsiran with BRII-179 induced a significant modification of immune responses demonstrated by anti-HBs antibody production and an expansion of interleukin 2-producing helper T cells specific for Pre-S1/Pre-S2 antigens only. Importantly, anti-HBs antibodies persisted at ≥100 IU/L in ∼40% of the participants for at least 32 weeks after combined treatment. Moreover, the neutralizing ability of the anti-HBs-positive sera was associated with HBsAg reduction.

CONCLUSIONS:

siRNA-induced HBsAg reduction may contribute to the persistence and efficacy of the humoral arm of HBV-specific adaptive immunity in CHB participants receiving the therapeutic vaccine BRII-179.

CLINICALTRIALS:

gov number: NCT04749368.

01 Jun 2025·JHEP Reports

Therapy with murinized tobevibart and elebsiran is efficacious in a liver-chimeric mouse model of HDV infection

Article

Author: Terrell, Ashley N ; Lempp, Florian A ; Zhou, Jiayi ; Puschnik, Andreas S ; Corti, Davide ; Rocha, Evelyn ; Kaiser, Hannah ; Purcell, Lisa A

Background & Aims:

Chronic hepatitis delta virus (HDV) infection represents the most severe form of viral hepatitis. HDV is a satellite virus of hepatitis B virus (HBV) and depends on the hepatitis B surface antigen (HBsAg) for envelopment and viral entry. Tobevibart (VIR-3434) is an investigational monoclonal antibody targeting the antigenic loop of HBsAg. Elebsiran (VIR-2218) is an investigational RNAi therapeutic targeting a highly conserved region within the HBV genome. The aim of this study was to investigate the antiviral effect of tobevibart and elebsiran on HDV infection in preclinical models.

Methods:

In vitro antiviral activity was determined in an HBV/HDV coinfection model in primary human hepatocytes (PHHs) or Huh7-NTCP cells. The in vivo efficacy of a murinized version of tobevibart alone or in combination with elebsiran was evaluated in HBV/HDV-coinfected liver-chimeric mice.

Results:

Elebsiran treatment reduced levels of secreted HBsAg and infectious HDV with picomolar potency. Tobevibart exhibited pan-genotypic neutralizing activity against all tested HDV genotypes with EC₅₀ ranging from 1.1 to 4.6 ng/ml. Combination treatment with tobevibart and elebsiran reduced infectious HDV levels in HBV/HDV-coinfected PHHs in an additive manner. In vivo, compared to vehicle, treatment with elebsiran, murinized tobevibart, or their combination significantly decreased HDV RNA serum levels by 0.7 log (p <0.0001), 1.6 log (p = 0.0034) and 2.1 log (p = 0.0002), respectively (measured at day 14 for elebsiran or day 21 for murinized tobevibart and the combination). HBsAg serum levels were reduced by 0.6 log (p <0.0001), 2.0 log (p <0.0001) and 2.8 log (p <0.0001), respectively.

Conclusions:

Tobevibart and elebsiran exert potent antiviral activity as single agents and in combination. The data support the clinical development of tobevibart and elebsiran for the treatment of patients with chronic HDV infection.

Impact and implications:

Chronic hepatitis delta is the most severe form of viral hepatitis and is associated with rapid progression of liver-related diseases and a high risk of hepatocellular carcinoma development. To date, there are only limited treatment options available. Tobevibart and elebsiran are currently being evaluated in clinical trials for the treatment of HDV (phase III) and for the treatment of HBV (phase II). The current study demonstrates that tobevibart and elebsiran are efficacious in preclinical models of HBV/HDV coinfection, supporting their clinical development.

01 Dec 2024·Lancet Gastroenterology & Hepatology

VIR-2218 (elebsiran) plus pegylated interferon-alfa-2a in participants with chronic hepatitis B virus infection: a phase 2 study

Article

Author: Lim, Tien-Huey ; Yuen, Man-Fung ; Gane, Edward ; Cloutier, Daniel ; Yoon, Ki Tae ; Gupta, Sneha V ; Arizpe, Andre ; Lim, Young-Suk ; Mao, Shenghua ; Heo, Jeong ; Thanawala, Vaidehi ; Cathcart, Andrea L ; Tak, Won Young ; Hwang, Carey ; Tangkijvanich, Pisit

BACKGROUND:

Chronic hepatitis B virus (HBV) remains a global concern, with current treatments achieving low rates of HBsAg seroclearance. VIR-2218 (elebsiran), a small interfering RNA agent against HBV transcripts, reduces HBsAg concentrations. We aimed to evaluate the safety and antiviral activity of VIR-2218 with and without pegylated interferon-alpha-2a treatment in participants with chronic HBV.

METHODS:

This open-label, phase 2 study was conducted at 23 sites in six countries (New Zealand, Australia, Hong Kong, Thailand, South Korea, and Malaysia). Adults (aged 18-65 years) with chronic HBV infection without cirrhosis and with HBsAg more than 50 IU/mL and HBV DNA less than 90 IU/mL who were on continued nucleoside or nucleotide reverse transcriptase inhibitor (NRTI) therapy for 2 months or longer were eligible. Participants were enrolled into one of six cohorts to receive VIR-2218 200 mg subcutaneously every 4 weeks, with or without 180 μg subcutaneous pegylated interferon-alfa-2a once per week. Cohort 1 received six doses of VIR-2218 (total 20 weeks); cohort 2 received six doses of VIR-2218 starting at day 1, plus 12 doses of pegylated interferon-alfa-2a starting at week 12 (total 24 weeks); cohort 3 received six doses of VIR-2218 and 24 doses of pegylated interferon-alfa-2a (total 24 weeks); cohort 4 received six doses of VIR-2218 and up to 48 doses of pegylated interferon-alfa-2a (total 48 weeks); cohort 5 received up to 13 doses of VIR-2218 and up to 44 doses of pegylated interferon-alfa-2a (total 48 weeks); and cohort 6 received three doses of VIR-2218 and 12 doses of pegylated interferon-alfa-2a (total 12 weeks). The primary endpoints were the incidence of adverse events and clinical assessments (including results of laboratory tests). Secondary endpoints were the mean maximum reduction of serum HBsAg at any timepoint; the proportion of participants with serum HBsAg seroclearance at any timepoint and for more than 6 months after the end of treatment; and the proportion of participants with anti-HBs seroconversion at any timepoint. For patients who were HBeAg-positive, we also assessed the proportion with HBeAg seroclearance or anti-HBe seroconversion at any timepoint. This study is registered with ClinicalTrials.gov, NCT03672188, and is ongoing.

FINDINGS:

Between July 2, 2020, and Nov 2, 2021, 124 individuals were screened for eligibility, 84 of whom were enrolled (15 in cohort 1, 15 in cohort 2, 18 in cohort 3, 18 in cohort 4, 13 in cohort 5, and five in cohort 6). Participants were predominantly HBeAg-negative, Asian, and male (66 [79%] participants were male and 18 [21%] were female). Most treatment emergent adverse events were grades 1-2. Three (20%) participants in cohort 1, four (27%) in cohort 2, eight (44%) in cohort 3, seven (39%) in cohort 4, six (46%) in cohort 5, and two (40%) in cohort 6 reported treatment-emergent adverse events related to VIR-2218. 12 (80%) participants in cohort 2, 12 (67%) in cohort 3, 14 (78%) in cohort 4, 13 (100%) in cohort 5, and three (60%) in cohort 6 reported treatment-emergent adverse events related to pegylated interferon-alfa-2a. Two (13%) participants in cohort 1 had elevations in alanine aminotransferase, compared with 13 (87%) participants in cohort 2, 15 (83%) in cohort 3, 17 (94%) in cohort 4, 11 (85%) in cohort 5, and three (60%) in cohort 6. The mean maximum change from baseline at any timepoint in HBsAg concentration was -2·0 log₁₀ IU/mL (95% CI -2·1 to -1·8) in cohort 1, -2·2 log₁₀ IU/mL (-2·5 to -1·8) in cohort 2, -2·5 log₁₀ IU/mL (-2·8 to -2·1) in cohort 3, -2·4 log₁₀ IU/mL (-3·1 to -1·8) in cohort 4, -3·0 log₁₀ IU/mL (-3·7 to -2·3) in cohort 5, and -1·7 log₁₀ IU/mL (-2·1 to -1·4) in cohort 6. 11 participants (one in cohort 2, one in cohort 3, five in cohort 4, and four in cohort 5) receiving VIR-2218 plus pegylated interferon-alfa-2a had HBsAg seroclearance at any timepoint. Of these, ten (91%; one in cohort 2, five in cohort 4, and four in cohort 5) had anti-HBs seropositivity. Six participants (one in cohort 2, three in cohort 4, and two in cohort 5) had sustained HBsAg seroclearance through to 24 weeks after the end of treatment. No participants receiving VIR-2218 monotherapy (cohort 1) or VIR-2218 plus pegylated interferon-alfa-2a 12-week regimen (cohort 6) had HBsAg seroclearance. 12 (42%) of 26 participants (one of four in cohort 1, two of six in cohort 2, four of seven in cohort 3, four of six in cohort 4, and one of three in cohort 5) who were HBeAg positive at baseline had HBeAg seroclearance or anti-HBe seroconversion.

INTERPRETATION:

The results of this phase 2 study support further development of VIR-2218 as a potential therapy for patients with chronic HBV infection. Additional clinical trials of VIR-2218 with and without pegylated interferon-alfa-2a in combination with an HBsAg-targeting monoclonal antibody are ongoing.

FUNDING:

Vir Biotechnology.

122

News (Medical) associated with Elebsiran

10 Nov 2025

·www.prnewswire.com

Brii Biosciences Presents Late-Breaking Data from Ongoing Phase 2 ENSURE Study at AASLD 2025, Reinforcing BRII-179's Potential as a Curative Treatment for Chronic Hepatitis B

Cohort 4 follow-up confirms durable hepatitis B surface antigen (HBsAg) loss at 24 weeks post end of treatment (EOT) in BRII-179 anti-HBs responders treated with elebsiran plus pegylated interferon alfa (PEG-IFNα) Data suggest the potential to shorten PEG-IFNα treatment duration for BRII-179 anti-HBs responders showing faster and greater HBsAg reduction DURHAM, N.C. and BEIJING, Nov. 10, 2025 /PRNewswire/ -- 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 24-week post end of treatment (EOT) follow-up results from Cohort 4 of its ongoing Phase 2 ENSURE study. These late-breaking data were presented at the American Association for the Study of Liver Diseases (AASLD) The Liver Meeting®, held in Washington D.C. from November 7-11, 2025, and were simultaneously published in Nature Medicine (link). ENSURE (NCT05970289) is a multicenter, open-label Phase 2 study in the Asia-Pacific region. Cohort 4 evaluates a novel sequential combination treatment strategy for hepatitis B virus (HBV), utilizing Brii Bio's therapeutic vaccine, BRII-179, to prime and enrich patients, with a goal to improve responsiveness to therapies potentially offering a functional cure. Participants previously treated with nine doses of elebsiran and BRII-179 treatment in a prior Phase 2 study BRII-179-835-001 (NCT04749368) were enrolled to this cohort to receive 48 weeks of combination treatment with elebsiran and PEG-IFNα. These participants were categorized as BRII-179 anti-HBs responders or non-responders based on their peak hepatitis B surface antibody (anti-HBs) levels during the prior study (≥10 IU/L or <10 IU/L, respectively). EOT data from Cohort 4 were previously presented at the European Association for the Study of the Liver (EASL) Congress 2025. The newly reported data confirm that the HBsAg loss benefit in the BRII-179 responder group was sustained over time. At EOT, 58% (11/19) HBsAg loss was observed in BRII-179 anti-HBs responders. In anti-HBs non-responders, only 17% (2/12) achieved HBsAg loss. At 24 weeks post EOT, 42% (8/19) of anti-HBs responders maintained HBsAg loss compared to 8% (1/12) of anti-HBs non-responders. 50% (4/8) of anti-HBs responders with sustained HBsAg loss at 24 weeks post EOT had baseline HBsAg levels between 1,514-3,086 IU/mL when enrolled in the previous BRII-179-835-001 study suggesting BRII-179 may elicit anti-HBs responses even in patients with higher baseline surface antigen levels. This supports BRII-179's potential to improve functional cure outcomes and broaden its applicability across diverse patient populations. To further define BRII-179's role in treatment of HBV infection and optimize combination regimens for pivotal studies, Brii Bio is conducting two additional Phase 2b trials. The ENRICH study evaluates the role of BRII-179 in priming HBV-specific immunity and/or identifying immuno-responsive patients with a higher likelihood of achieving functional cure. The ENHANCE study includes two parts: one to evaluate the triple combination of BRII-179, elebsiran and PEG-IFNα given concurrently for 48 weeks, and another exploring a sequential approach of BRII-179 and elebsiran for 24 weeks followed by triple combination for 24 weeks, and a 48-week PEG-IFNα control arm. Both studies are fully enrolled, and EOT data are expected to be presented in 2026. "We are encouraged to see that the difference in HBsAg seroclearance rates observed at EOT was maintained through 24 weeks of follow-up." said David Margolis, MD, Chief Medical Officer of Brii Bio. "These results support BRII-179's potential to deliver more rapid and durable HBsAg loss and potentially enable a shorter treatment duration of PEG-IFNα. We look forward to validating these findings in our ongoing confirmatory studies." Publication Number: 5036 Title: Chronic hepatitis B virus infected participants responding to prior BRII-179 treatment achieved higher rate of sustained hepatitis B virus surface antigen loss on elebsiran plus pegylated interferon alfa: follow-up 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 A total of 31 participants were analyzed, with 19 BRII-179-induced anti-HBs responders and 12 non-responders. Median [range] HBsAg at baseline of this ENSURE study was numerically higher in anti-HBs responders (520 [34-2165] IU/mL) than in non-responders (185 [51-672] IU/mL). At 24 weeks post EOT, a notably higher rate of HBsAg loss was achieved in BRII-179-induced anti-HBs responders (8/19, 42.1%) compared to non-responders (1/12, 8.3%). Although all participants with sustained HBsAg loss had HBsAg < 1,500 IU/mL at baseline of this ENSURE study, 4/8 (50.0%) from anti-HBs responders had baseline HBsAg ranging from 1,514-3,086 IU/mL when enrolled in the previous study, suggesting that BRII-179 may induce anti-HBs responses regardless of baseline HBsAg level. The elebsiran and PEG-IFNα combination was generally safe and well-tolerated. 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 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. In May 2024, the CDE of the NMPA granted elebsiran Breakthrough Therapy Designation. 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 . SOURCE Brii Biosciences Limited 21% more press release views with Request a Demo

Phase 2Clinical ResultBreakthrough TherapyLicense out/in

09 Nov 2025

·endpoints.news

Corrected: Phase 2 data from Vir’s hepatitis D combo regimen underscore market potential

New data from Vir Biotechnology’s chronic hepatitis D treatment reinforce the combo regimen’s promise of keeping viral levels low, as the company’s pivotal trials advance ahead of schedule. Vir said Sunday evening that a monthly injection of tobevibart and elebsiran helped two-thirds of patients achieve and sustain viral levels below detection in a Phase 2 study. The 66% of patients meeting that endpoint, also known as target not detectable (TND), is up from the 41% reported at the 24-week mark. Chief medical officer Mark Eisner described the results in an interview with Endpoints News as “very, very strong antiviral efficacy.” Vir unveiled the results at the American Association for the Study of Liver Diseases annual meeting, and they were also published in the New England Journal of Medicine . Alanine aminotransferase (ALT) levels, another marker of treatment effect, were normalized in 56% of patients by 48 weeks. The share of treated patients who reported both ALT normalization and viral levels below detection — which Vir previously described as a “more stringent composite endpoint” — was 38%. The safety profile of the combo regimen remained strong, with no reported treatment-related adverse events of grade 3 or higher and no treatment-related discontinuations. All of the events were grade 1 or grade 2, generally mild to moderate, and only lasted a brief period, according to Vir. The new data add further fuel behind the company’s rapid advancement of the treatment through pivotal trials. One of the company’s three Phase 3 studies has completed enrollment two months ahead of the company’s “aggressive internal deadline,” Eisner said. That trial, ECLIPSE 1, takes patients who are virulent with hepatitis D and randomizes them to either Vir’s combo or a deferred treatment. A second trial involves patients who have taken Gilead’s bulevirtide for at least six months and randomizes them to either bulevirtide for another 24 weeks or Vir’s treatment. A third and final study is a head-to-head trial of Vir’s combo and bulevirtide in treatment-naïve patients. “Given that we’re seeing 66% TND at 48 weeks in SOLSTICE … we think we have a really good chance of having a positive outcome in that study,” Eisner said of the head-to-head study. When asked why the company was running a head-to-head study before gaining FDA approval, Eisner said it’s meant to make the case to European payers where bulevirtide is already approved. Vir now says that interim results from all three ECLIPSE studies could come in the first quarter of 2027, though Eisner declined to say when Vir may submit data to regulators. Editor’s note: The headline was corrected to reflect that Vir presented new Phase 2 data, not Phase 3.

Phase 2Clinical ResultPhase 3

07 Nov 2025

·www.prnewswire.com

Brii Biosciences Announces Publication of Phase 2 ENSURE Study Results in Nature Medicine

Findings provide scientific insights into the contribution of small interfering RNA (siRNA) and therapeutic vaccination towards the HBV functional cure strategy DURHAM, N.C. and BEIJING, Nov. 7, 2025 /PRNewswire/ -- Brii Biosciences Limited ("Brii Bio," or the "Company," stock code: 2137.HK), a biotechnology company developing therapies to improve patient health across diseases with high unmet medical need, today announced the publication of results from its Phase 2 ENSURE study in the peer-reviewed journal Nature Medicine. The study evaluates the efficacy and safety of an siRNA, elebsiran, in combination with pegylated interferon alfa (PEG-IFNα), compared to PEG-IFNα monotherapy. Furthermore, this study evaluates the potential role of an HBV therapeutic vaccine, BRII-179, in identifying immunologically responsive patients and improving hepatitis B surface antigen (HBsAg) loss rates. The article, titled "Elebsiran and PEG-IFNα for chronic hepatitis B infection: a partially randomized, open-label, phase 2 trial", is now available online [link]. The ENSURE study was conducted in two parts in virally suppressed chronic HBV patients. In Part I (Cohorts 1-3), participants naïve to BRII-179 were randomized to receive 48 weeks of PEG-IFNα alone or in combination with elebsiran (200 mg or 100 mg administered every 4 weeks [Q4W]). In Part II (Cohort 4), participants previously treated with 9 doses of elebsiran and BRII-179 in a completed Phase 2 study (BRII-179-835-001) were categorized as BRII-179 anti-HBs responders or non-responders based on peak hepatitis B surface antibody (anti-HBs) levels (≥10 IU/L or <10 IU/L, respectively), and subsequently received 48 weeks of elebsiran (100 mg Q4W) plus weekly PEG-IFNα in the ENSURE study. Key results from this publication include: Cohorts 1-3: At 24 weeks post-EOT, HBsAg loss was observed in 4 of 19 participants (21.1%) in Cohort 2 (elebsiran 200 mg + PEG-IFNα) and 6 of 18 participants (33.3%) in Cohort 3 (elebsiran 100 mg + PEG-IFNα), compared to 1 of 18 participant (5.6%) in Cohort 1 (PEG-IFNα monotherapy). Cohort 4: At 24 weeks post-EOT, HBsAg loss was observed in 9 of 31 participants (29.0%), with a notably higher response among BRII-179 anti-HBs responders (8/19, 42.1%) compared to non-responders (1/12, 8.3%). BRII-179 anti-HBs responders also achieved more rapid HBsAg reductions and HBsAg seroclearance compared to non-responders. Elebsiran and PEG-IFNα combination therapy was generally safe and well tolerated across all cohorts. The randomized, active-controlled design of Cohorts 1-3 was a gold standard in validating the clinical benefit of elebsiran over PEG-IFNα monotherapy, providing an important benchmark for future development of siRNA towards HBV functional cure. The novel design of Cohort 4 explored a patient response-guided treatment approach for more personalized decision-making, maximizing response rates in those most likely to benefit while avoiding unnecessary and lengthy treatments in others. Other important observations are 1) participants previously treated with BRII-179 and elebsiran experienced faster decline and loss of HBsAg, suggesting that BRII-179 may prime the immune system for improved responsiveness to subsequent curative therapy; 2) 50% (4/8) of anti-HBs responders who achieved sustained HBsAg loss had baseline HBsAg levels exceeding 1,500 IU/mL when enrolled in the previous BRII-179-835-001 study, suggesting that BRII-179 may elicit anti-HBs responses in patients with high baseline HBsAg levels. With its favorable safety profile, BRII-179 could play a unique role in priming and enriching patients regardless of the baseline HBsAg levels, expanding the population eligible for future curative regimens. "The ENSURE study was designed to provide much-needed clarity and to answer critical scientific questions about curative treatment for chronic hepatitis B," said Professor Jidong Jia, lead principal investigator of the ENSURE study, "It is encouraging to see that the 24-week follow-up data remain consistent with the EOT results, substantiating the added clinical benefit of elebsiran and pointing to the potential new roles of BRII-179 in priming and enriching CHB patients for achieving higher cure rates. We look forward to validating these findings in confirmatory studies." 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 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. In May 2024, the CDE of the NMPA granted elebsiran Breakthrough Therapy Designation. 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 . SOURCE Brii Biosciences Limited 21% more press release views with Request a Demo

Clinical ResultPhase 2Breakthrough Therapy

100 Deals associated with Elebsiran

R&D Status

10 top R&D records.

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Indication	Highest Phase	Country/Location	Organization	Date
Hepatitis D, Chronic	Phase 3	United States	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	Canada	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	Germany	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	Moldova	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	New Zealand	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	Pakistan	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	Romania	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	Ukraine	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis D, Chronic	Phase 3	United Kingdom	Vir Biotechnology, Inc.	12 Mar 2025
Hepatitis B, Chronic	Phase 2	United States	Vir Biotechnology, Inc.	03 Jul 2020

Clinical Result

Indication

Phase

Evaluation

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Study	Phase	Population	Analyzed Enrollment	Group	Results	Evaluation	Publication Date


ENSURE (PRNewswire) Manual	Phase 2	Hepatitis B	28	BRII-179 (Cohort 4 + previously responded to BRII-179)	ikkozfxeij(sbnyvovbmi) = ihkymgyxrh fmrdnfteuf (qesdogjjle )	Positive	21 Aug 2025
				BRII-179BRII-179 (Cohort 4 + previously non-responders to BRII-179)	ikkozfxeij(sbnyvovbmi) = lvpmhqkjwl fmrdnfteuf (qesdogjjle )
NCT04856085 (MARCH, Company_Website) Manual	Phase 2	Hepatitis B, Chronic	83	Tobevibart + Elebsiran	cbyalwnyqa(qfvkriuucw) = vktrqoiaoi ammxiqdyuq (rjnyjmpxxm ) View more	Positive	09 May 2025
				Tobevibart + Elebsiran + PEG-IFNα	cbyalwnyqa(qfvkriuucw) = otbpmcusck ammxiqdyuq (rjnyjmpxxm ) View more
NCT05970289 (ENSURE, PipelineReview) Manual	Phase 2	Hepatitis B, Chronic	31	Elebsiran + PEG-IFNα (Cohort 4)	rsegluxlmy(bgjsnhvtsp) = pubekmvffi wljtjtbkwb (poukksdkym )	Positive	31 Mar 2025
				Elebsiran + PEG-IFNα (Cohort 4 + BRII-179 responders)	rsegluxlmy(bgjsnhvtsp) = shqykcqqkw wljtjtbkwb (poukksdkym )
NCT03672188 (Pubmed \| Lancet Gastroenterol Hepatol)	Phase 1/2	Hepatitis B, Chronic	-	VIR-2218 200 mg + Pegylated interferon-alfa-2a	owoggykhnm(qyjwsozdue) = 20% in cohort 1, 27% in cohort 2, 44% in cohort 3, 39% in cohort 4, 46% in cohort 5, 40% in cohort 6 vxnoaxeqhm (zwxbuasjro ) View more	-	01 Dec 2024
NCT05970289 (ENSURE, NEWS) Manual	Phase 2	Hepatitis B	-	Elebsiran 200 mg+PEG-IFNα	atrlcopqmq(fnkivwtuvz) = fkatoesxti gzpusobmwe (nrtneepkyu ) View more	Positive	19 Nov 2024
				Elebsiran 100mg+PEG-IFNα	atrlcopqmq(fnkivwtuvz) = uefctctlbm gzpusobmwe (nrtneepkyu ) View more
NCT04507269 (CTgov)	Phase 2	Hepatitis B, Chronic	21	VIR-2218 (Part 1: VIR-2218 50 mg)	todahafdbz = gtlgwcyrfq dgyuvtlppf (nzfypnspzz, ibgglilijs - pczpecabho) View more	-	26 Aug 2024
				VIR-2218 (Part 1: VIR-2218 100 mg)	todahafdbz = jypwfzoqhd dgyuvtlppf (nzfypnspzz, aafuhirzmh - kqhhonzlft) View more
NCT03672188 \| NCT02826018 (Pubmed \| J Hepatol)	Phase 1/2	Hepatitis B, Chronic	-	VIR-2218	ebwmhnvkjs(zfqfhrwnzl) = eaiqvdsdul rqgozkfvow (petgykwmge )	-	06 Jun 2023
GlobeNewswire Manual	Phase 2	Hepatitis B	-	VIR-2218VIR-2218 (six-dose regimen of VIR-2218)	szlbqfbjkm(mvuhftszsk) = all participants achieving a >1 log10 IU/mL reduction during the trial. faczcvympo (mbtdkvwsgf ) View more	Positive	25 Jun 2022
				VIR-2218VIR-2218 (two-dose regimen of VIR-2218)
EASL2021	Phase 2	Hepatitis B, Chronic	27	VIR-2218 alone	thovuwypoy(hwvnafneft) = Some participants receiving Peg-IFNa and VIR-2218 combination experienced asymptomatic ALT elevations (grade 2 – 3) concurrent with HBsAg decline ( ≥ 1 log 10 IU/ ml). ALT elevations were not associated with functional changes of the liver (bilirubin, PT or INR). No serious AEs have been reported. enwcxahokf (lxmbwjeoyg )	-	23 Jun 2021
				VIR-2218 + Peg-IFNa

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