11/15/2024
 
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- 39% of participants with low baseline Hepatitis B surface antigen (HBsAg) achieved HBsAg loss with tobevibart + elebsiran, and 46% with tobevibart + elebsiran + pegylated interferon alfa -
 
- No new safety concerns were identified, and treatment-emergent adverse events were generally mild to moderate -
 
< - Late-breaking oral presentation of MARCH Part B study results at the American Association for the Study of Liver Diseases (AASLD) The Liver Meeting® -
 
- Key functional cure data from 24-week follow-up expected in Q2 2025 -
 
SAN FRANCISCO--(BUSINESS WIRE)-- Vir Biotechnology, Inc. (Nasdaq: VIR) today announced end-of-treatment data from Part B of the MARCH Phase 2 clinical study evaluating combinations of tobevibart and elebsiran, with or without pegylated interferon alfa (PEG-IFNα), in participants with chronic hepatitis B. The study demonstrated promising rates of hepatitis B surface antigen (HBsAg) loss (seroclearance) in participants with low baseline HBsAg (<1000 IU/mL) in both combination regimens. The efficacy and safety profile support continued development to evaluate the potential to achieve a functional cure. Detailed data will be presented in a late-breaking oral presentation at the American Association for the Study of Liver Diseases (AASLD) The Liver Meeting ® , in San Diego, CA, on November 18 at 5:00 p.m. PT. Vir Biotechnology will host an investor conference call on November 19, at 5.15 a.m. PT / 8.15 a.m. ET.
 
Chronic hepatitis B (CHB) is a long-lasting, inflammatory liver disease caused by the hepatitis B virus (HBV) 1 . The World Health Organization estimates that 254 million people live with CHB, and an estimated 1.1 million yearly deaths are associated with the disease 2 . Complications from CHB may include liver cirrhosis, liver failure and liver cancer 3 . Although CHB can be treated, there is no cure 1 .
 
Participants in the trial received tobevibart and elebsiran alone (doublet regimen) or in combination with PEG-IFNα (triplet regimen). This analysis includes data from 51 participants in the doublet regimen arm and 27 participants in the triplet regimen arm at the end of treatment. Tobevibart was administered at 300 mg every 4 weeks; elebsiran, at 200 mg every 4 weeks; and PEG-IFNα at 180 µg weekly. Study primary endpoints include HBsAg seroclearance (defined as HBsAg below the lower limit of quantification) and treatment-emergent adverse events (TEAEs) at end of treatment. Secondary endpoints include anti-HBs seroconversion (defined as development of anti-HBs≥10 mIU/mL) at end of treatment.
 
The doublet and triplet regimens resulted in HBsAg loss at the end of treatment in 39% (7/18) and 46% (5/11) of participants with baseline HBsAg<1,000 IU/mL, respectively. The proportion of participants with varying baseline HBsAg levels who achieved HBsAg loss at end of treatment was 16% (8/51) for the doublet and 22% (6/27) for the triplet regimen. The doublet regimen resulted in 50% (4/8) of participants who had achieved HBsAg loss also achieving anti-HBs seroconversion. All participants with HBsAg loss at the end of treatment who received the triplet regimen achieved anti-HBs seroconversion (100%, 6/6). Participants with HBsAg seroclearance at end of treatment who meet eligibility criteria will discontinue treatment. Functional cure assessment will occur 24 weeks after treatment discontinuation.
 
"People living with chronic hepatitis B must settle for life-long treatments that don't eliminate the risk of disease progression to liver cancer," said Edward J. Gane, M.D., Professor of Medicine at the University of Auckland, New Zealand and Chief Hepatologist, Transplant Physician and Deputy Director of the New Zealand Liver Transplant Unit at Auckland City Hospital. "These latest data at end of treatment are encouraging as they suggest that tobevibart in combination with elebsiran could be key components for a hepatitis B functional cure. I look forward to the further results from this study anticipated next year."
 
The safety and tolerability profile of tobevibart and elebsiran was consistent with prior studies, with no new safety concerns identified. TEAEs were generally mild or moderate. "At Vir Biotechnology our ambition is to develop a functional cure for chronic hepatitis B following a finite treatment regimen. The MARCH data suggests that tobevibart and elebsiran can clear HBsAg and re-ignite the immune system, producing antibodies to potentially keep the virus under control," said Mark Eisner, M.D., M.P.H., Executive Vice President and Chief Medical Officer, Vir Biotechnology. "We are encouraged by these results and eagerly anticipate the functional cure data in 2025, as it will be decisive for the next steps of clinical development."
 
The data will be presented in the oral presentation Tobevibart (VIR-3434) and elebsiran (VIR-2218) with or without pegylated interferon alfa-2a for the treatment of chronic HBV infection: end of treatment results after 48 weeks of therapy (MARCH study) by Edward Gane, M.D., during a late breaking parallel session at AASLD The Liver Meeting® on November 18 at 5:00 pm PT.