FDA Extends Review of Hemophilia A Gene Therapy

The FDA has extended the review of BioMarin Pharmaceutical’s biologics license application (BLA) for Roctavian (valoctocogene roxaparvovec) gene therapy for adults with severe hemophilia A. The new PDUFA target action date is June 30, 2023

Hemophilia A is a genetic disease caused by the deficiency of clotting factor VIII. It is the most common type of hemophilia and occurs much more frequently in males; incidence is estimated at 1 in 4,000-5,000 male births.

BioMarin’s gene therapy uses an adeno-associated virus vector to deliver a functional gene to the cells in the liver that is designed to enable the body to produce Factor VIII on its own without the need for continued hemophilia prophylaxis.

The FDA determined that the company’s submission of the three-year data analysis from the ongoing phase 3 GENEr8-1 study is a major amendment due because of the amount of additional data. The company had anticipated that extra time would be needed for review when it resubmitted its BLA in October 2022 following a complete response letter issued on Aug. 18, 2020.

“The three-year data enhance our application and further reinforce our belief that Roctavian has the potential to fundamentally transform care for people with hemophilia A,” Hank Fuchs, M.D., president of Worldwide Research and Development of BioMarin, said in a press release.

Results of a phase 3 trial with 134 patients were released in January 2023, and found that mean annualized bleed rate was reduced by 80% and Factor VIII usage was reduced by 94% in year three. At the end of year 3, 92% of patients remained off prophylaxis.To date, a single dose of Roctavian has been well tolerated with no delayed-onset treatment related adverse events. In year 3, no new treatment-related serious adverse events or Grade 3 events attributed to Roctavian or corticosteroid use emerged.

The company is also conducting a phase 3, single arm, open-label study to evaluate the efficacy and safety of Roctavian with prophylactic corticosteroids in people with severe hemophilia A. Also ongoing is a phase 1/2 study in people with severe hemophilia A with pre-existing AAV5 antibodies and a phase 1/2 study in people with severe hemophilia A with active or prior Factor VIII inhibitors.