The FDA has approved Ultragenyx Pharma’s gene therapy Fayuvi as the first treatment for Sanfilippo syndrome type A, a rare neurodegenerative disease. The therapy, priced at $3.9 million, offers hope to children with this condition, also known as MPS IIIA. Fayuvi (rebisufligene etisparvovec; formerly UX111) is a one-shot treatment designed to halt the progression of this devastating disease, which typically reduces the average lifespan to around 15 years.
Fayuvi, or rebisufligene etisparvovec, is a one-time treatment that addresses the root cause of MPS IIIA. The disease is caused by a defect in the SGSH gene, leading to a deficiency of the sulfamidase enzyme. This deficiency results in the abnormal accumulation of heparan sulfate in the body and brain, causing cognitive and developmental decline. An intravenous infusion of Fayuvi delivers a functional copy of the SGSH gene to patient cells via a viral vector, preventing this harmful buildup.
In clinical trials, children aged two to five who received Fayuvi showed maintained or improved cognitive function compared to an untreated historical control cohort. The therapy’s approval follows a previous rejection by the FDA last year, which requested additional manufacturing data. This approval is a sign of the perseverance of the Sanfilippo community, researchers, and industry partners.
Read Also: FDA Pilot Aims to Accelerate U.S. Drug Trials
Ultragenyx justifies the high price tag by noting that the lifetime cost of caring for a child with MPS IIIA can reach $8 million. The company aims to make Fayuvi available through treatment centers within the next 30 to 60 days. Chief Executive Emil Kakkis emphasized the urgency of making this therapy accessible, highlighting the company’s commitment to working with treatment centers and payers to support families.
Fayuvi is Ultragenyx’s second approved gene therapy, following Genglycos (pariglasgene brecaparvovec) for glycogen storage disease type Ia (GSDIa), which was cleared by the FDA in August and priced at $2.7 million. With an estimated 3,000 to 5,000 patients affected by MPS IIIA in the developed world, Fayuvi’s approval offers a new path forward for families facing this devastating disease.
