FDA Gives Orphan Drug Designation for Hemophilia A Gene Therapy

Note: The below is an edited version of a press release by BioMarin Pharmaceutical Inc. The original release can be read in its entirety here.

BioMarin Pharmaceutical Inc. announced on Tuesday, March 1, that BMN 270, an investigational gene therapy for the treatment of patients with hemophilia A, has been granted orphan drug designation by the U.S. Food and Drug Administration (FDA). BioMarin is currently conducting a Phase 1/2 study to evaluate the safety and efficacy of BMN 270 gene therapy in up to 12 patients with severe hemophilia A and will provide a program update in April. BMN 270 is an AAV 5 factor VIII vector, designed to restore factor VIII plasma concentrations, essential for blood clotting in patients with hemophilia A. The FDA Orphan Drug program provides orphan designation to drugs and biologics that are intended for the treatment of rare diseases (those affecting fewer than 200,000 people in the United States).
Study Design
The Phase 1/2 study will evaluate the safety and efficacy of BMN 270 gene therapy in up to 12 patients with severe hemophilia A. The primary endpoints are to assess the safety of a single intravenous administration of a recombinant AAV, human-coagulation Factor VIII vector and to determine the change from baseline of Factor VIII expression level at 16 weeks after infusion. The kinetics, duration and magnitude of AAV-mediated Factor VIII activity in individuals with hemophilia A will be determined and correlated to an appropriate BMN 270 dose. This is a dose escalation study with the goal of observing an increase in Factor VIII levels. Secondary endpoints include assessing the impact of BMN 270 on the frequency of Factor VIII replacement therapy, the number of bleeding episodes requiring treatment and any potential immune responses. Patients will be monitored for safety and durability of effect for 5 years.
About Gene Therapy
Gene therapy is a form of treatment designed to fix a genetic problem by adding a corrected copy of the defective gene. The functional gene is inserted into a vector, containing a small DNA sequence, that acts as a delivery mechanism, providing the ability to deliver the functional gene to cells. The cells can then use the information to build the functional proteins that the body needs, potentially reducing or eliminating the cause of the disease. Currently, gene therapy for the treatment of hemophilia A is available only as part of a clinical trial.