Pfizer Inc has entered into an agreement to acquire Encysive Pharmaceuticals Inc., a publicly held biopharmaceutical company whose product for the treatment of pulmonary arterial hypertension (PAH) is commercially available in much of the European Union and is approved in other markets.

Pfizer will acquire the rights to THELIN (sitaxsentan sodium), an oral, once-daily endothelin for $195 million. A receptor antagonist (ETRA) for the treatment of PAH, as well as Encysive’s other pipeline candidates.

THELIN has been approved for marketing in the European Union, and is currently available in many EU states, including the United Kingdom, Germany, Ireland, Spain, France, Italy, Belgium, Luxembourg and the Netherlands. THELIN has also been approved in Australia and Canada. In the United States, THELIN has been the subject of three approvable letters from the US Food and Drug Administration.

Pfizer has come with a superior offer and with an in-depth understanding of pulmonary arterial hypertension, our primary therapeutic focus and plans to conduct a pivotal Phase III trial to support registration in the US.  Pfizer has about 1,200 employees in research and development operations in the St. Louis area. Pfizer said the deal would strengthen its portfolio in products treating high blood pressure.