Wednesday, Feb 6, 2002

Phase III Tracleer (bosentan) Study in Chronic Heart Failure Does Not Meet Primary Efficacy Objective

Long-term data confirms safety profile observed in earlier Pulmonary Arterial Hypertension trials

Allschwil, Switzerland and South San Francisco, Calif. -- February 6, 2002 --

Actelion Ltd (SWX New Market: ATLN) and Genentech, Inc. (NYSE: DNA) today announced the Phase III ENABLE program evaluating endothelin receptor antagonist Tracleer™ (bosentan) in 1,613 patients with severe chronic heart failure (CHF NYHA Class IIIb/IV) did not reach statistical significance in the two pre-defined primary endpoints: risk reduction in time to death or hospitalization due to CHF, and improvement in clinical status at nine months of treatment.

Isaac Kobrin, Head of Clinical Development at Actelion, commented: "Though we did not see efficacy in CHF for Tracleer, the ENABLE trial did importantly generate long-term data about safety in patients receiving Tracleer for up to 30 months, confirming the same safety profile as observed in earlier clinical trials. This is an important finding for Tracleer's first approved indication, Pulmonary Arterial Hypertension. We are encouraged by this safety finding in a larger patient population and will further evaluate the use of Tracleer in other indications. Actelion is in the process of preparing new clinical trial programs for Tracleer."

Under an agreement concluded in December 2000, in certain circumstances Genentech has opportunity to become a co-promotion partner for Tracleer. An option was exercisable if the ENABLE study reached statistical significance for the primary endpoints. Based on the ENABLE results, Genentech cannot exercise this option but can explore other opportunities under the current agreement.

The full findings of the ENABLE trial, including subgroup analyses, will be presented at the American College of Cardiology meeting, March 17-21, in Atlanta.

Tracleer is currently available in the United States as a treatment for pulmonary arterial hypertension. The drug was approved for this indication by the U.S. Food and Drug Administration on November 20, 2001, and is currently marketed by Actelion Pharmaceuticals US. The drug is also available in Canada and currently under regulatory review in the European Union, Switzerland and Australia.

Genentech, Inc.

Genentech, Inc., is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant unmet medical needs. Fifteen of the currently approved products of biotechnology are based on or stem from Genentech science. Genentech markets ten products directly in the United States. The company has headquarters in South San Francisco, California and is traded on the New York Stock Exchange under the symbol DNA.

Actelion Ltd

Actelion Ltd is a biopharmaceutical company headquartered in Allschwil/Basel Switzerland and has a substantial US operation based in South San Francisco. Actelion 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).

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