Encysive Pharmaceuticals has announced that the US Food and Drug Administration (FDA) has accepted for review the company's complete response to the July 24, 2006 approvable letter regarding its New Drug Application (NDA) for Thelin (sitaxsentan sodium) 100 mg tablets.

The FDA has designated the review as a class 2 re-submission and issued a new Prescription Drug User Fee Act (PDUFA) target action date of June 15, 2007.

The FDA as a potential new oral treatment is currently evaluating Thelin for patients with pulmonary arterial hypertension (PAH).

The company will work with the FDA to schedule a meeting as soon as possible in an effort to clarify the situation and move the application forward.

Encysive is currently in the process of commercialising Thelin 100 mg in the European Union, following the August 2006 receipt of marketing authorization from the European Commission. To date, Thelin has been launched in the United Kingdom and Germany.