Long-term safety tracking for gene therapy in bleeding disorders

This is a follow-up study for people with hemophilia A or B who previously received either giroctocogene fitelparvovec or fidanacogene elaparvovec—experimental gene therapy treatments designed to help their bodies produce clotting factors naturally. Researchers want to understand how safe and effective these treatments remain over the long term by continuing to monitor participants who received them in earlier studies.

Gene therapies for bleeding disorders are relatively new, so doctors need to gather long-term information about how well this medication works over months and years, and whether any new safety concerns emerge with time.