Gene Therapy with Fidanacogene Elaparvovec in Adults with Hemophilia B.
Background Fidanacogene elaparvovec, an adeno-associated virus (AAV) gene-therapy vector for hemophilia B containing a high-activity human factor IX variant (FIX-R338L/FIX-Padua), was associated with sustained factor IX activity in a phase 1-2a study. Methods We conducted a phase 3 open-label study of fidanacogene elaparvovec at a dose of 5×1011 vector genome copies per kilogram of body weight. Me