FDA approves treatment for rare genetic enzyme disorder

FDA approved Wednesday vestronidase alfa-vjbk (Mepsevii—Ultragenyx Pharmaceutical) for the treatment of pediatric and adult patients with mucopolysaccharidosis type VII (MPS VII). The extremely rare and progressive inherited metabolic condition affects less than 150 patients worldwide.

FDA approved Wednesday vestronidase alfa-vjbk (Mepsevii—Ultragenyx Pharmaceutical) for the treatment of pediatric and adult patients with mucopolysaccharidosis type VII (MPS VII). The extremely rare and progressive inherited metabolic condition affects less than 150 patients worldwide. "This approval underscores the agency's commitment to making treatments available to patients with rare diseases," said Julie Beitz, MD, director of the Office of Drug Evaluation III in FDA's Center for Drug Evaluation and Research. "Prior to today's approval, patients with this rare, inherited condition had no approved treatment options." The safety and efficacy of vestronidase alfa-vjbk were established in clinical trial and expanded access protocols that included a total of 23 patients aged 5 months to 25 years. Participants received treatment with vestronidase alfa-vjbk at doses up to 4 mg/kg once every 2 weeks for up to 164 weeks. Efficacy was measured primarily with the 6-minute walk test in 10 patients who could perform it. After 24 weeks of treatment, the mean difference in distance walked relative to placebo was 18 meters. Further followup for up to 120 weeks suggested continued improvement in 3 patients and stabilization in the rest. The most frequent adverse events reported following treatment with vestronidase alfa-vjbk included infusion site reactions, diarrhea, rash, and anaphylaxis. FDA is requiring manufacturer Ultragenyx to conduct a post-marketing study to assess the long-term safety of vestronidase alfa-vjbk.