Shares of Encysive took a beating this morning as investors digested the news from late Friday that the FDA required more clinical data on its experimental drug for pulmonary arterial hypertension before it could be approved. Its stock plunged 46 percent in early trading today. Encysive has been racing to gain regulatory approval of a new drug for PAH. Encysive CEO Bruce Given said that the company hoped it could satisfy the FDA's concerns outlined in its "approvable letter" without additional clinical work. Talks with the FDA to clarify the issue are being planned. Encysive's Thelin works by regulating blood vessels.
Investors were clearly worried that the delay would allow Encysive's competitors to steal a march in the approval process. Myogen's ambrisentan is in a second pivotal trial for PAH and shares of Switzerland's Actelion rose at the prospect that Tracleer would continue without a new competitor for an uncertain period.
- read the AP report for more information