Gilead to appeal FDA cystic fibrosis trial demand

LOS ANGELES, Nov 13 (Reuters) - Gilead Sciences Inc (GILD.O) plans to appeal a request by the U.S. Food and Drug Administration for an additional clinical study of the company's experimental cystic fibrosis drug, a spokeswoman said on Thursday.

"Gilead intends to appeal the decision with the FDA on the basis of what we believe is the strength of the efficacy and safety of aztreonam lysine and of its overall clinical profile as outlined in our new drug application," Gilead's Cara Miller said in a emailed statement.

The agency said in September it would not approve the drug unless the company conducted an additional trial. The ruling surprised analysts, who said the request would delay the launch of the drug by as much as two years.

Gilead applied for approval of the drug to treat lung infections associated with cystic fibrosis, a genetic disease in which the body produces a thicker-than-normal mucus that clogs the lungs and other organs.

Gilead said at the time that the agency did not raise any significant concerns regarding the drug's safety.

Prior to the FDA's ruling, analysts at Oppenheimer & Co estimated that sales of the cystic fibrosis treatment would reach $105 million in 2010, rising to $205 million in 2012. (Reporting by Deena Beasley and Toni Clarke; Editing by Andre Grenon)