Monday, Feb 12, 2001

Phase III Trial of Intravenous Endothelin Receptor Antagonist Tezosentan for Acute Heart Failure Shows Positive Hemodynamic Results

Allschwil, Switerland and South San Francisco, Calif. -- February 12, 2001 --

Actelion Ltd (SWX New Market: ATLN) and Genentech, Inc. (NYSE: DNA) announced today that tezosentan - an intravenous dual endothelin receptor antagonist - demonstrated positive hemodynamic results in a pivotal clinical study of 292 patients suffering from acute heart failure (AHF). AHF is a life-threatening condition where the ability of the heart to pump enough blood to meet the body's metabolic needs is rapidly and seriously impaired.Detailed results of RITZ (Randomized Intravenous TeZosentan) 2 will be presented during the annual meeting of the American College of Cardiology (ACC), Orlando, FL, at the late-breaking clinical trials session on Tuesday, March 20, 2001.

RITZ 2 is the first of two pivotal studies that comprise the tezosentan Phase III clinical trial program; the second is RITZ 1, a 670-patient study evaluating tezosentan's ability to alleviate the symptoms of AHF, including dyspnea (shortness of breath). RITZ 4 and 5 complete the program as supportive studies.

"We are pleased with the results of the RITZ 2 pivotal Phase III trial - the first of our four studies. However, we must remember that the full benefit-risk ratio can only be assessed at the end of the complete program," said Isaac Kobrin, MD, Head of Clinical Development for Actelion.

"We are encouraged by the initial findings of RITZ 2, which show positive changes in cardiac hemodynamics among this difficult to treat patient population," said Hal V. Barron, MD, Genentech's senior director, Cardiopulmonary Research. "We look forward to learning more about tezosentan as the complete Phase III data profile emerges later in the year."

Last February, Genentech and Actelion signed an agreement to develop and co-promote tezosentan for the treatment of AHF, and to co-promote Genentechis new single bolus thrombolytic TNKaseTM (Tenecteplase). In December 2000, the companies announced the signing of a second agreement for the development and co-promotion of Actelionis oral endothelin receptor antagonist TracleerTM (bosentan) for pulmonary hypertension and congestive heart failure for which Actelion leads the development efforts and commercialization.

It is estimated that nearly one million people in the U.S. are hospitalized each year with acute heart failure, a medical emergency usually requiring rapid relief of symptoms and improvement of hemodynamics (blood circulation). AHF can occur as a decompensation of chronic heart failure, as an acute complication of heart attack, and following cardiac surgery.

Typically, AHF patients present with an increase of existing symptoms such as dyspnea, edema and fatigue, as well as signs of poor blood flow. In some cases, the onset of AHF is abrupt, with rapid fluid build-up in the lungs (pulmonary edema), which can impair breathing so drastically that the patient requires intubation and a ventilator for assisted breathing. In other cases, AHF can lead to cardiogenic shock, an abrupt disruption of blood flow that can follow a massive heart attack or surgery.

Actelion Ltd, a biopharmaceutical company headquartered in Allschwil, Switzerland, is the global leader in creative science related to the endothelium -- the single layer of cells separating every blood vessel from the blood stream. Actelion concentrates on developing and bringing innovative drugs to patients. Tracleero and tezosentan, its two flagship drugs, are in late stage development for several cardiovascular disorders, including chronic and acute heart failure as well as pulmonary arterial hypertension. In addition, Actelion is conducting drug discovery programs in cardiovascular diseases, malaria, Alzheimeris disease and cancer. Actelion is quoted on the Swiss Stock Exchange (SWX New Market: ATLN).

Genentech, Inc., is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant unmet medical needs. Fourteen of the currently approved biotechnology products stem from Genentech science. Genentech markets nine biotechnology 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.

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