Actelion Ltd. operates as a holding company with interests in developing, producing and marketing pharmaceutical drugs. It is a biopharmaceutical company, which focuses on the drug discovery, development, registration, production and commercialization of innovative drugs for diseases with significant unmet medical needs. Its portfolio of PAH treatments covers the spectrum of disease, from WHO Functional Class (FC) II through to FC IV, with oral, inhaled and intravenous medications. It has treatments for specialist diseases, including Type 1 Gaucher disease, Niemann-Pick type C disease, digital ulcers in patients suffering from systemic sclerosis and mycosis fungoides in patients with cutaneous T-cell lymphoma. The company products include Tracleer (bosentan), Zavesca (miglustat), Ventavis (iloprost), Veletri (epoprostenol for injection), Valchlor and Opsumit (macitentan). The company was founded by Jean-Paul Clozel, Martine Clozel, Walter Fischli, AndrÃ© J. Mueller, and Thomas Widmann on December 17, 1997 and is headquartered in Allschwil, Switzerland.