The US Food and Drug Administration has rejected BioMarin's gene therapy for hemophilia A, Reuters reports.
Hemophilia A affects nearly 20,000 people in the US, who lack the factor VIII clotting protein, and BioMarin's Roctavian (valoctocogene roxaparvovec) uses a virus to deliver a working version of the gene encoding the protein to spur patients to produce the clotting factor on their own, the Associated Press adds. Currently, hemophilia A patients undergo infusions of these proteins often, a treatment Reuters says can cost hundreds of thousands of dollars a year. With this therapy, the hope was that patients would be able to avoid or limit the number of infusions they need, the AP adds.
But the FDA told BioMarin it needs to supply more longer-term data, according to Reuters. It adds that BioMarin submitted its application based on data from its three-year Phase 1/2 study and an analysis of interim data from its Phase 3 study, but the FDA noted there were differences between the trials' data that made it difficult to determine how long the treatment would be effective. The agency has asked for the full two-year data from BioMarin's ongoing late-stage study, it adds.
The AP notes there had been questions about whether the drug would be a lifetime fix or a treatment that lasts a few years, especially following rumors that the treatment might cost as much as $3 million per patient, which would make it the most expensive therapy to be approved.