Vestronidase alfa, sold under brand name Mepsevii, is a drug for the treatment of Sly syndrome. It is a recombinant form of the human enzyme beta-glucuronidase. It was approved in the United States in November 2017, to treat children and adults with an inherited metabolic condition called mucopolysaccharidosis type VII (MPS VII), also known as Sly syndrome. MPS VII is an extremely rare, progressive condition that affects most tissues and organs.The most common side effects after treatment with vestronidase alfa include infusion site reactions, diarrhea, rash (urticaria) and anaphylaxis (sudden, severe allergic reaction).The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication. It was approved for use in the European Union in August 2018. Medical uses
Mepsevii is indicated for the treatment of non-neurological manifestations of Mucopolysaccharidosis VII (MPS VII; Sly syndrome). History
The safety and efficacy of vestronidase alfa were established in a clinical trial and expanded access protocols enrolling a total of 23 participants ranging from five months to 25 years of age. Participants received treatment with vestronidase alfa at doses up to 4 mg/kg once every two weeks for up to 164 weeks. Efficacy was primarily assessed via the six-minute walk test in ten participants who could perform the test. After 24 weeks of treatment, the mean difference in distance walked relative to placebo was 18 meters. Additional follow-up for up to 120 weeks suggested continued improvement in three participants and stabilization in the others. Two participants in the vestronidase alfa development program experienced marked improvement in pulmonary function.
Drug Information Portal. U.S. National Library of Medicine. Clinical trial number NCT02230566 for "A Phase 3 Study of UX003 Recombinant Human Betaglucuronidase (rhGUS) Enzyme Replacement Therapy in Patients With Mucopolysaccharidosis Type 7 (MPS 7)" at ClinicalTrials.gov