FDA issues BioMarin complete response letter for Duchenne muscular dystrophy drug Kyndrisa

BioMarin Pharmaceutical announced Thursday that the FDA issued a complete response letter related to the company's filing for the Duchenne muscular dystrophy (DMD) treatment Kyndrisa (drisapersen). BioMarin said it is reviewing the letter and will work with the agency to determine the appropriate next steps.

"FDA has concluded that the standard of substantial evidence of effectiveness has not been met," BioMarin indicated. Company spokewoman, Debra Charlesworth said that although specific details have not been provided, the agency asked BioMarin to conduct another trial before the drug could be reconsidered for approval.

Last November, FDA staff concluded that clinical data backing BioMarin's submission of Kyndrisa did not warrant approval. An FDA advisory panel later voted 15-2 that a Phase III study of Kyndrisa failed to uncover a significant improvement in the distance walked in six minutes, weakening the findings from two earlier studies. BioMarin disclosed last month that the FDA had delayed issuing a final determination on whether to approve the drug.

RBC Capital Markets analyst Michael Yee remarked that the rejection was not a surprise. "Investors nearly fully expected a rejection of drisapersen," Yee said, adding "the stock should bounce back now that this is out of the way and we can move on to the next pipeline catalysts."

The drugmaker noted that it will continue ongoing extension studies of Kyndrisa in addition to ongoing clinical trials for other experimental exon-skipping oligonucleotides, namely BMN 044, BMN 045 and BMN 053.

Meanwhile, an FDA advisory panel is expected to review Sarepta Therapeutics' experimental DMD drug eteplirsen, which was granted rare paediatric disease designation by the agency, later this month, with a final decision on whether to approve the drug anticipated in February. Additionally, PTC Therapeutics initiated a rolling submission of the DMD drug Translarna (ataluren), which has been granted conditional approval in Europe for nonsense mutation DMD, in the US in December 2014. Last October, the company announced Phase III results showing that Translarna failed to achieve significance on the study’s primary endpoint.(For related analysis, read ViewPoints: PTC's failed Translarna study could turn out to be a big success.)

For further analysis, see ViewPoints: BioMarin's rough ride at an FDA AdComm may be good news for Sarepta, PTC Therapeutics.

An application for marketing approval of Kyndrisa is also under review in Europe. with BioMarin expecting a final decision from the European Commission by the second half of this year.

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