Prospects For GSK/XenoPort's Horizant Sink After Rejection By FDA

The news that FDA rejected GlaxoSmithKline/XenoPort's NDA for Horizant (gabapentin enacarbil) for restless leg syndrome due to a carcinogenicity signal in rats took Wall Street by surprise and crushed XenoPort, which lost more than half its market value Feb. 18. The companies issued a press release announcing receipt of an FDA "complete response" letter for Horizant after the market closed on Feb. 17