Actelion Ltd, a biopharmaceutical company, engages in the discovery, development, and commercialization of low molecular weight drugs for various medical needs. Its principal products include Tracleer, an orally available dual endothelin receptor antagonist, approved as a therapy for pulmonary arterial hypertension (PAH), a chronic, life-threatening disorder that severely compromises the functions of the lungs and heart; and Zavesca, in-licensed from Oxford GlycoSciences, an oral medication indicated for the oral treatment of adult patients with mild to moderate type 1 Gaucher disease. The company also offers Ventavis, an inhaled synthetic analogue of prostacyclin that produces potent pulmonary vasodilation and inhibits platelet aggregation. In addition, Actelion evaluates various compounds in various phases of clinical development for treating cardiovascular, cardiopulmonary, immunological, and infectious diseases, as well as metabolic and central nervous system disorders. In addition, it has an exclusive worldwide alliance with Merck & Co, Inc. to discover, develop, and market new classes of renin inhibitors for patients suffering from cardio-renal diseases. Actelion markets Tracleer in the United States, the European Union, Japan, Canada, Australia, and Switzerland. The company was founded in 1997 and is headquartered in Allschwil, Switzerland.