(Corrects spelling of name in paragraphs 3 and 4 to De Kerpel from Dekerpel)
* Drug being developed to treat Duchenne muscular dystrophy
* Company to submit U.S. marketing application later this year
* Approval expected by 2015 at the earliest - analyst
By Natalie Grover
June 3 Prosensa Holding NV said the U.S. Food and Drug Administration had outlined an accelerated regulatory approval path for its most advanced drug, aimed at treating a muscle disorder.
The Netherlands-based company said on Tuesday it planned to conduct two more studies, and file for U.S. marketing approval later this year. Prosensa said it would file for European approval in the near future.
Like Sarepta Therapeutics Inc's eteplirsen, Prosensa's drug to treat Duchenne muscular dystrophy (DMD) will probably win U.S. approval in 2015 at the earliest, leaving each with about half of the market, said Jan De Kerpel, an analyst at KBC Securities in Brussels.
De Kerpel expects the drug to generate peak global sales of 1 billion euros ($1.36 billion) by the end of the decade, and estimates it will cost about 200,000 euros a year per patient.
Prosensa's treatment will likely fare better than Sarepta's in Europe as it holds a patent advantage in the region, he said.
The company's shares were down about 0.6 percent in mid-morning trading after rising as much as 3.9 percent.
Drisapersen, like eteplirsen, is designed to enhance the production of a protein called dystrophin, the lack of which causes DMD.
DMD drugs-in-development have received encouraging signals from regulators in recent months.
The FDA indicated an alternate path for approval to Sarepta's eteplirsen in April, while European regulators recommended conditional approval for PTC Therapeutics Inc's Translarna last month.
Prosensa said in January it would pursue the development of drisapersen despite its failure in a late-stage trial, after additional data showed its use could slow disease's progression.
Earlier that month, partner GlaxoSmithKline Plc returned the rights to the drug to Prosensa, terminating a 2009 collaboration deal to develop it.
Accelerated approval is usually granted to drugs for serious diseases with no treatment options, based on data from initial trials. However, a company still needs to conduct larger trials to bolster its initial findings.
DMD is a degenerative disorder that hampers muscle movement. It affects one in 3,600 newborn boys, who usually succumb to the disease by the age of 30.
Prosensa's shares were trading at $10.56 on the Nasdaq in mid-morning trading on the Nasdaq. ($1 = 0.7349 Euros) (Reporting by Natalie Grover in Bangalore; Editing by Joyjeet Das and Kirti Pandey)