The Food and Drug Administration has decided against approving the exon 51-skipping antisense oligonucleotide drug drisapersen for forms of Duchenne muscular dystrophy amenable to exon skipping.
The agency’s complete response letter to BioMarin Pharmaceutical, the developer of drisapersen (Kyndrisa), said that the standard of substantial evidence of effectiveness had not been met, according to a written statement from the company on Jan. 14.
In a Nov. 24, 2015, meeting of the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee, panel members generally felt that drisapersen’s efficacy data were not persuasive enough for an approval.
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Drisapersen targets frame-disrupting mutations found in exon 51 of the dystrophin gene, which produces a nonfunctional protein in individuals with a certain form of Duchenne, by restoring expression of the mutated dystrophin gene. There are currently no FDA-approved drugs to treat Duchenne, which affects approximately 1 in every 3,500 to 1 in 5,000 male children, making it the most common fatal genetic disorder diagnosed in childhood.
BioMarin said that extension studies of drisapersen will continue as the company determines the next steps in its new drug application, as will the ongoing clinical trials for other exon-skipping oligonucleotides it is developing. The drug is still under review by the European Medicines Agency.