TRACLEER PROMISING AS DIGITAL ULCER TREATMENT.

Actelion Ltd. (SWX: ATLN), Allschwil/Basel, Switzerland, has reported preliminary results from RAPIDS-1, evaluating the efficacy and safety of TracleerTM in the treatment of digital ulcerations in scleroderma patients. The primary endpoint of the study, the prevention of new digital ulcers, was achieved. This result was highly statistically significant.

Isaac Kobrin, head of clinical development, said: "I am very pleased with these promising results. We knew already that scleroderma patients benefit from TracleerTM treatment if they suffer from pulmonary arterial hypertension, for which the drug is already approved. Now we have evidence that scleroderma patients suffering from digital ulcers may also benefit from TracleerTM treatment. Moreover, this randomized study has again confirmed the safety and tolerability profile of TracleerTM in the scleroderma patient population."

Actelion will immediately start the process to obtain a second Orphan Drug designation for TracleerTM, this time for digital ulcerations in scleroderma patients. The company will also discuss the full results with authorities worldwide to determine the appropriate procedures for a regulatory filing. Full results of RAPIDS-1 will be submitted for presentation at upcoming scientific meetings, with publication to follow.

TracleerTM, the first orally available dual endothelin receptor antagonist, is already approved and available in major markets worldwide for the treatment of pulmonary arterial hypertension (PAH), a chronic life-threatening condition that severely compromises the function of the lungs and heart. Between 15 to 30 percent of all scleroderma patients develop PAH, the leading cause of mortality in these patients.

TracleerTM in Digital Ulcers - Investigator comments Digital ulcerations are also a common complication of scleroderma, occurring in 25 percent or more of patients. Digital ulcerations are very painful and difficult to heal open sores, occurring on fingers and toes, as a result of the blockage of small blood vessels (obliterative vasculopathy). In severe cases, where gangrene might develop, surgery and even amputation may be required.

The lead investigator of Rapids-1, Carol Black, CBE, MD, Professor of Rheumatology, Royal Free Hospital, London, said: "I am delighted with the results of this study. For the first time in a placebo-controlled study, an oral drug has been shown to prevent new digital ulcers in scleroderma patients. These findings, taken together with the proven efficacy of TracleerTM in pulmonary arterial hypertension, are clearly supportive of the hypothesis that endothelin plays a fundamental role in vasculopathy. In addition, endothelin may also contribute to the pathophysiology of scleroderma itself."

The lead investigator in the United States, Joseph H. Korn, MD, Professor of Medicine and Biochemistry, School of Medicine, Boston University, said: "The finding that TracleerTM prevents the occurrence of new digital ulcers in scleroderma patients is both statistically significant and also clinically relevant. The decrease in digital ulcers means that patients will have less pain and improved function as well as a lower risk of serious finger infection."

The study RAPIDS-1 (RAndomized Placebo-controlled Investigation of Digital ulcers in Scleroderma) was an international, multi-center, double-blind, placebo-controlled clinical trial evaluating the prevention of ischemic digital ulcers in 122 patients with systemic sclerosis (scleroderma). Patients were randomized in a 2:1 allocation to either TracleerTM or placebo for a sixteen-week treatment period. Patients had to either have active digital ulcers at entry into the study or to have a history of digital ulcerations in the preceding twelve months.

Tracleer(tm) today - Approved in Pulmonary arterial hypertension Tracleer(tm), the first orally available dual endothelin receptor antagonist, is currently approved and available in the United States, the European Union (Germany and UK, others to follow), Canada and Switzerland for the treatment of Pulmonary Arterial Hypertension, a chronic life-threatening condition that severely compromises the function of the lungs and heart.

Approximately 100,000 people in Europe and the United States are afflicted with either primary pulmonary arterial hypertension or secondary forms of the disease related to conditions or tissue disorders that affect the lungs, such as scleroderma, lupus, HIV/AIDS, congenital heart disease or the use of certain appetite suppressants.

In clinical trials leading to the marketing approval of the drug, approximately 11 % of PAH patients receiving Tracleer(tm) experienced abnormal but reversible liver enzyme elevations. It is therefore important that patients undergo monthly liver monitoring. Due to the risk of birth defects, women who are pregnant, or woman of childbearing age who do not use a reliable method of contraception, must not take Tracleer(tm).

Actelion Ltd.

Actelion Ltd. is a biopharmaceutical company, with its corporate headquarters in Allschwil/Basel, Switzerland. Actelion's first drug Tracleer(tm), an orally available dual endothelin receptor antagonist, has been approved as a therapy for pulmonary arterial hypertension. Actelion markets Tracleer(tm) through its own subsidiaries in key markets worldwide, including the United States (based in South San Francisco), the European Union as well as Canada and Switzerland. Actelion, founded in late 1997, is a leading player in innovative science related to the endothelium - the single layer of cells separating every blood vessel from the blood stream. Actelion focuses on the discovery, development and marketing of innovative drugs for significant unmet medical needs. Actelion shares are traded on the Swiss Stock Exchange (SWX New Market ATLN).

For more information, call 650 624-6936 or visit http://www.actelion.com.