The company said it anticipates filing a request with the agency for formal dispute resolution "in the near term" on the issue of whether Encysive submitted sufficient data with the FDA to prove its potential drug Thelin is effective for treating pulmonary arterial hypertension.

Encysive said it had a preliminary meeting with officials from the agency regarding the status of the company's marketing application for Thelin, a meeting that included Encysive regulatory officials and a lead investigator of the firm's STRIDE-2 clinical trial, Robyn Barst, professor of pediatrics at Columbia University College of Physicians and Surgeons, and director of the NewYork-Presbyterian Hospital Pulmonary Hypertension Center.

Encysive filed for approval of Thelin in February 2005 and received an approvable letter from the FDA June 15 notifying the company of its decision that "Encysive's clinical development program for Thelin did not demonstrate significant evidence of efficacy needed for approval."