FDA Approves Gene Therapy for Pediatric Patients With Sanfilippo Syndrome Type A

The Food and Drug Administration approved rebisufligene etisparvovec-hopf on Sept. 17, marking the first FDA-approved treatment for pediatric patients with mucopolysaccharidosis type IIIA (MPS IIIA), also known as Sanfilippo syndrome type A.

Rebisufligene etisparvovec-hopf uses a modified, non-infectious adeno-associated virus (AAV) serotype 9 vector to deliver a working copy of the SGSH gene into the patient’s cells. This enables the body’s cells to produce sulfamidase, the enzyme that is missing or deficient in MPS IIIA, allowing heparan sulfate to be properly broken down in lysosomes and reducing its harmful buildup throughout the body and brain.

FDA based the approval on an open-label, single-arm, multicenter clinical study that evaluated cognitive function in pediatric patients with MPS IIIA. Children aged 2 to 5 years who received the therapy maintained or improved cognitive function compared with an untreated historical control cohort.

The most common adverse reactions included increased increased liver enzymes (AST), nausea and vomiting, fever, decreased appetite, decreased white blood cell and platelet counts, and increased amylase. FDA also identified risks of thrombotic microangiopathy and potential long-term tumor development associated with genome integration.

Rebisufligene etisparvovec-hopf received Orphan Drug, Fast Track and Breakthrough Therapy designations.