The FDA granted orphan drug designation to an investigational gene therapy for patients with hemophilia A, a disease that approximately 1 in 10,000 people are born with.

Hemophilia A, also known as factor VIII (FVIII) deficiency, is a genetic disorder caused by the defective or missing clotting protein FVIII.

The drug, an AAV 5 factor VIII vector called BMN 270, was designed to restore FVIII plasma concentrations, which are essential for creating blood clots in hemophilia A patients.

Currently, BioMarin is conducting a phase 1/2 study to determine the efficacy and safety of BMN 270 in 12 patients with severe hemophilia A.

The primary endpoints for the study are to find the safety of a single intravenous administration of human-coagulation FVIII vector and determine the change from the baseline of FVIII expression level after 16 weeks of infusion. The duration and amount of AAV-mediated FVIII activity will be determined and correlated in a correct BMN 270 dose.

The secondary endpoints will assess the impact of BMN 270 with the amount of bleeding episodes that require treatment and potentially immune responses. These patients will be monitored for 5 years and BioMarin will be providing a study update in April.