FDA Approves First Gene Therapy for Severe Hemophilia A

FRIDAY, June 30, 2023 (HealthDay News) -- The U.S. Food and Drug Administration on Thursday approved a costly single-dose gene therapy for patients with severe hemophilia A. The treatment, Roctavian (valoctocogene roxaparvovec), will cost $2.9 million for a single infusion, the Associated Press reported.

Drug maker BioMarin Pharmaceutical Inc. told the AP that the drug's astronomical price tag reflects "the possibility of freedom from years" of infusions with other medications. Those infusions typically run about $800,000 each year for patients, the AP said.

How frequent and severe bleeding episodes are depends on the amount of factor VIII (FVIII) protein a person produces. In about 60 percent of cases, people with severe hemophilia A have less than 1 percent of FVIII in their blood. Before now, treatment has involved FVIII replacement therapy or an antibody-based medication, the FDA said.

Roctavian is a viral vector that carries the gene for FVIII. It reduces the risk of uncontrolled bleeding by delivering the gene into the liver, to increase blood levels of FVIII.

The approval was based on a multinational study which determined the drug's safety and effectiveness in adult men ages 18 to 70 who had previously had FVIII replacement therapy. A total of 112 patients were followed for at least three years. Those treated in the study had far fewer bleeding incidents. Their mean annualized bleeding rate dropped from 5.4 times each year to 2.6. Most of those who received Roctavian also took corticosteroids to suppress their immune system. The FDA noted that treatment response may decrease over time.

Adverse reactions seen in the study included mild changes in liver function, headache, nausea, vomiting, fatigue, abdominal pain, and infusion-related reactions. The treatment is not without risks. The FDA recommends close monitoring for infusion-related reactions and elevated liver enzymes. An increase in FVIII activity could potentially increase the risk of blood clots, the FDA noted. The product also carries a potential cancer risk.

Approval of Roctavian was granted to BioMarin.

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