Prosensa to file for US, EU approval of Duchenne muscular dystrophy drug drisapersen

Shares in Prosensa rose as much as 13 percent Tuesday after the drugmaker disclosed that, following positive feedback from the FDA, it plans to file for accelerated approval of drisapersen later this year as a treatment for Duchenne muscular dystrophy (DMD). The company added that it has also been in talks with the European Medicines Agency and intends to file the drug in Europe as well.

As part of its FDA filing strategy, Prosensa said it would initiate two confirmatory post-approval studies of drisapersen, as defined in earlier guidance and which the agency had urged the company to begin as soon as possible. Specifically, the regulator suggested that evidence of drisapersen's clinical benefit might be provided from a historically-controlled trial, as well as a randomised study comparing the therapy to another exon-skipping treatment with a similar mechanism of action and targeting a different exon. Prosensa added that in the third quarter it will also continue with plans to re-dose an initial cohort of patients with DMD who participated in prior trials of its experimental therapy.

CEO Hans Schikan stated that "we could not be more pleased with this favourable outcome and with the regulatory authorities' willingness to advance investigational products for the treatment of DMD." The company regained all rights to drisapersen in January, when GlaxoSmithKline terminated a 2009 collaboration following the drug's failure to significantly improve outcomes in a 6-minute walking distance test versus placebo in a late-stage study. Schikan added that Prosensa has been "preparing for multiple scenarios since acquiring the rights back," as well as "completing our more detailed analysis of the drisapersen dataset."

Commenting on the news of Prosensa's upcoming regulatory filings, KBC Securities analyst Jan De Kerpel noted that drisapersen is likely to win FDA approval in 2015 at the earliest, as should Sarepta Therapeutics' exon-skipping drug candidate eteplirsen, which Sarepta recently said would be submitted for US clearance by the end of the year. De Kerpel predicted the therapies are likely to split the DMD market, with drisapersen generating peak global sales of 1 billion euros ($1.4 billion) by the end of the decade, with an annual cost of 200 000 euros ($272 590) per patient. Moreover, the analyst added that drisapersen may fare better in Europe than eteplirsen because it holds a patent advantage in the region.

Meanwhile, the EMA's Committee for Medicinal Products for Human Use recently backed conditional approval of PTC Therapeutics' experimental DMD therapy Translarna (ataluren), reversing a previous negative opinion on the drug.

To read more Top Story articles, click here.