FDA Grants Breakthrough Designation to Spark Therapeutics' Hemophilia B Drug

Spark Therapeutics and Pfizer announced that the U.S. Food and Drug Administration (FDA) has granted breakthrough therapy designation to SPK-9001, the lead investigational candidate in the companies’ SPK-FIX program, in development for the treatment of hemophilia B. SPK-9001, a novel bio-engineered adeno-associated virus (AAV) capsid expressing a codon-optimized, high-activity human factor IX variant, is being investigated in an ongoing Phase 1/2 trial as a potential one-time therapy.

Breakthrough therapy designation is intended to expedite the development and FDA review of drugs to treat a serious or life-threatening disease or condition. The designation requires preliminary clinical evidence that the investigational therapy may offer substantial improvement over existing therapies on at least one clinically significant endpoint.

In addition to SPK-9001, Spark Therapeutics previously received breakthrough therapy designation for voretigene neparvovec, which is being developed for the potential treatment of inherited retinal disease (IRD) caused by mutations in the RPE65 gene.

“We are extremely pleased to have been granted breakthrough therapy designation for SPK-9001, which has shown early promise in achieving our goal of eliminating the need for regular infusions to control and prevent bleeding episodes in patients with hemophilia B through a potentially one-time, intravenous administration of a highly optimized gene therapy,” said Jeffrey D. Marrazzo, chief executive officer of Spark Therapeutics. “Together with Pfizer, we look forward to working closely with the FDA to bring SPK-9001 to patients as quickly and responsibly as possible.”