Fidanacogene Elaparvovec: First Approval.

Fidanacogene elaparvovec (PrBEQVEZ™) is an adeno-associated viral (AAV) vector-based gene therapy developed by Spark Therapeutics (a subsidiary of Roche) and Pfizer (under a license from Spark Therapeutics) for the treatment of haemophilia B. In December 2023, fidanacogene elaparvovec received its first approval for the treatment of adults (aged ≥ 18 years) with moderately severe to severe haemophilia B (congenital factor IX deficiency) who are negative for neutralizing antibodies to variant AAV serotype Rh74 (AAVRh74var). Fidanacogene elaparvovec is under regulatory review in the USA and the European Union and clinical studies are ongoing in multiple countries. This article summarizes the milestones in the development of fidanacogene elaparvovec leading to this first approval for moderately severe to severe (factor IX activity ≤ 2%) haemophilia B who are negative for neutralizing antibodies to AAVRh74var.