FDA Approves First Gene Therapy for Pediatric Patients with Sanfilippo Syndrome Type A

The U.S. Food and Drug Administration has granted approval for Fayuvi (rebisufligene etisparvovec-hopf) as the first treatment for pediatric patients with mucopolysaccharidosis type IIIA, also known as Sanfilippo syndrome type A. The condition is a rare inherited disorder that causes progressive damage to the brain and nervous system, leading to a loss of developmental abilities over time.

Fayuvi is administered as a one-time intravenous infusion. It uses a modified adeno-associated virus to deliver a working copy of the SGSH gene into cells, enabling the body to produce the missing sulfamidase enzyme and reduce the harmful buildup of heparan sulfate. The approval was based on a clinical study where treated patients maintained or improved cognitive function compared to untreated historical controls.

Common adverse reactions include increased liver enzymes, nausea, vomiting, fever, decreased appetite, reduced white blood cell and platelet counts, and increased amylase. Important safety warnings include the risk of thrombotic microangiopathy and a potential long-term risk of tumor development from genomic integration. Patients must receive corticosteroid treatment starting prior to the infusion and continuing for at least eight weeks.