Fidanacogene elaparvovec (BEQVEZ®) is the second gene therapy approved in Europe for the treatment of severe and moderate haemophilia B, which received conditional marketing authorisation from the European Commission on 24 July 2024. The medication, distributed by Pfizer, is classified as an "Advanced Therapy Medicinal Product" (ATMP). The approval covers the treatment of adults with no history of factor IX inhibitors and no detectable antibodies against AAVRh74var.

Fidanacogene elaparvovec demonstrated a 71% reduction in the annual bleeding rate compared to previous FIX prophylaxis therapy in a single-arm Phase 3 study (BENEGENE-2, n=45). The effect was maintained for up to 48 months. Side effects occurred in 84% of treated patients, with 16% experiencing serious reactions. The most common side effect was elevated aminotransferase levels (53%). Since the therapy is administered only once intravenously, surveyed patients express optimism about the reduced treatment burden and improved quality of life that may result from a simplified therapy form and treatment freedom. Given the existing uncertainties regarding long-term efficacy and potential side effects, it is recommended that patients receive the infusion in specialised centres with subsequent monitoring in local facilities. In addition, mandatory follow-up of all treated patients is considered necessary.

In Austria, 130 patients were reported by the Austrian Haemophilia Society (ÖHR) in 2024. Of these, 22.3% were affected by moderate haemophilia and 24.6% by severe haemophilia. According to clinical experts' assessment, nine patients would be eligible for the therapy with increasing uptake over three years (Year 1: 20%, Year 2: 30%, Year 3: 50%).