Vir Biotech Gets EMA Positive Opinion on Orphan Drug Status for Tobevibart and Elebsiran in Chronic Hepatitis Delta

Vir Biotechnology, Inc. has reported that the European Medicines Agency Committee for Orphan Medicinal Products (COMP) has given a favorable opinion on the application for orphan drug designation for two investigational treatments, tobevibart and elebsiran, aimed at combating chronic hepatitis delta (CHD). This decision is backed by positive preliminary data from the Phase 2 SOLSTICE trial. Vir Biotechnology is set to present 24-week data from this trial at The Liver Meeting® hosted by the American Association for the Study of Liver Diseases (AASLD) in San Diego.

Chronic hepatitis delta (CHD) is a severe liver disease driven by the hepatitis delta virus (HDV) and is considered the most aggressive form of chronic viral hepatitis. Patients often progress to severe liver complications such as cirrhosis and liver failure within five years of infection. There are currently no approved treatments for this condition in the United States, and global treatment options remain limited.

Mark Eisner, M.D., M.P.H., Executive Vice President and Chief Medical Officer of Vir Biotechnology, highlighted the critical necessity for new therapeutic solutions given the severe risks posed by CHD, including the potential for liver cancer and death. Eisner emphasized that the positive opinion from COMP on the combined use of tobevibart and elebsiran indicates the potential of this treatment approach to fill a significant gap in CHD care.

The European Commission will now assess COMP's positive opinion to potentially grant orphan drug designation to tobevibart and elebsiran. This designation is reserved for treatments targeting rare, life-threatening, or chronically debilitating conditions with no satisfactory treatment options, or where the treatment can offer significant benefits to those affected. Benefits of this designation in the EU include access to specific scientific advice, fee reductions, and a decade of market exclusivity post-approval.

Additionally, in June 2024, the U.S. Food and Drug Administration (FDA) granted fast track designation for the combination of tobevibart and elebsiran for CHD treatment. This designation is intended to expedite the development and review process for drugs treating serious conditions with unmet medical needs.

The Phase 2 SOLSTICE trial is a multi-center, open-label, randomized study evaluating the safety, tolerability, and effectiveness of tobevibart alone or combined with elebsiran in CHD patients. Key endpoints include the proportion of participants with undetectable HDV RNA by week 24, normalization of alanine aminotransferase (ALT) levels by week 24, as well as monitoring treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs) over 118 weeks. Secondary endpoints include the proportion of participants with undetectable HDV RNA at various time points up to 192 weeks.

Tobevibart is an investigational monoclonal antibody targeting the hepatitis B surface antigen, designed to block the entry of hepatitis B and delta viruses into liver cells and reduce viral particles in the bloodstream. Tobevibart, incorporating technologies from Xencor, is engineered for an extended half-life and is administered subcutaneously. It is currently being developed for both chronic hepatitis B and chronic hepatitis delta patients.

Elebsiran, also investigational, is a small interfering ribonucleic acid (siRNA) targeting hepatitis B virus RNA transcripts to limit the production of the hepatitis B surface antigen. Early data suggest it may have direct antiviral activity against both hepatitis B virus and hepatitis delta virus. Administered subcutaneously, elebsiran represents the first asset in Vir Biotechnology's collaboration with Alnylam Pharmaceuticals, Inc. to enter clinical trials.

Vir Biotechnology, Inc. is a clinical-stage biopharmaceutical company dedicated to harnessing the immune system to address serious infectious diseases and cancer. Its clinical portfolio includes programs targeting chronic hepatitis delta and B infections, as well as several validated targets in solid tumor indications. The company also maintains a preclinical portfolio spanning various infectious diseases and oncologic malignancies.