Tuesday March 2, 3:53 am Eastern Time
GENEVA, March 2 (Reuters) - Ares-Serono Group said on Tuesday that the U.S. Food and Drug Administration had requested more clinical information and data on Rebif, its interferon beta 1-a drug for treating multiple sclerosis.
The FDA has also made a labelling proposal for both doses of the drug and stated that Rebif may not get U.S. marketing approval amid orphan drug exclusivity for two other medications, Ares-Serono said in a statement. Its shares were down 160 Swiss francs or 6.5 percent to 2,295 around 0835 GMT.
"Serono does not see any difficulty in responding quickly to the FDA request for more information necessary for tentative Rebif approval," Hisham Samra, president of Serono Laboratories, said in the statement. "We have also received a proposal for labelling for both doses which we are in the process of evaluating."
The FDA also informed Ares-Serono in a letter that there were pending orphan exclusivity issues that were separate from the clarifications of Rebif data the agency requested. "The FDA has further stated that Rebif may not be approved for marketing while orphan exclusivity remains in effect for Avonex or Betaseron," it added. Avonex is made by Biogen (Nasdaq:BGEN - news). Betaseron, developed and marketed by Berlex Laboratories, is made by Chiron Corp (Nasdaq:CHIR - news).
"Serono will continue its discussions with the FDA on outstanding orphan drug issues to determine how it can make Rebif available to MS patients as soon as possible," Samra said.
Many analysts have described Rebif as a potential blockbuster for Ares-Serono
so any delay in U.S. approval was seen as negative for the stock.
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