HAMBURG, Germany - Actelion Ltd., of Allschwil, Switzerland, reported positive results of its Phase III clinical trial in pulmonary hypertension.

According to the company, treatment with its new compound, Bosentan, an endothelin antagonist, significantly improved hemodynamics and increased the exercise capacity of the patients in a randomized, placebo-controlled, double-blind study involving 32 patients.

The new compound targets the endothelium, a single layer of cells forming an interface between blood and the surrounding tissue maintaining the tone of the blood vessels. The endothelium produces active compounds such as endothelin, one of the most powerful constrictors of blood vessels. An abnormal stimulation of endothelin plays a major role in the progression of several diseases of the heart. (See BioWorld International, March 29, 2000.)

Bosentan also is in Phase III trials in chronic heart failure. - Ludger Wess