Thursday, Apr 19, 2001

Phase III Clinical Trial of Veletri for the Treatment of Acute Heart Failure Symptoms Does Not Meet Primary Efficacy Objective

Pivotal trial in AHF symptoms does not show benefit in dyspnea, while earlier Phase III hemodynamic trial showed statistically significant results

Allschwil, Switzerland and South San Francisco, Calif. -- April 19, 2001 --

Actelion Ltd (SWX New Market: ATLN) and Genentech, Inc. (NYSE: DNA) announced today that RITZ-1, the second pivotal Phase III clinical trial of Veletri™ (tezosentan) – an intravenous dual endothelin receptor antagonist – did not meet its primary objective of significantly improving symptoms (dyspnea, or shortness of breath) associated with acute heart failure (AHF).

"The preliminary results of RITZ-1 are in contrast with the results of the first Veletri pivotal study (RITZ-2) that showed highly significant improvements in hemodynamics, and an improvement in dyspnea," said Isaac Kobrin, MD, head of clinical development for Actelion. "Genentech and Actelion will work together to analyze the complete RITZ database and to discuss further actions for the development of Veletri," said Hal V. Barron, MD, Genentech's senior director of Cardiopulmonary Research.

RITZ-1 (Randomized Intravenous TeZosentan), with 675 patients enrolled, is the second of two pivotal studies in the RITZ Phase III clinical trial program. The trial was designed to evaluate the ability of 50mg/hr of Veletri plus standard treatment to reduce the clinical symptoms of AHF, based on the patient's assessment of dyspnea in the absence of hemodynamic evaluation. Secondary endpoints, including time to death or worsening of heart failure, did not reach statistical significance.

"The results of RITZ-1 highlight the challenges of demonstrating clinical improvements with new therapeutic agents in patients with acute heart failure beyond those observed with objective central hemodynamic monitoring," Dr. Kobrin added.

Designed in tandem with RITZ-1, the 292-patient RITZ-2 study evaluated Veletri's ability to improve hemodynamics (blood flow from and to the heart) in patients with AHF. RITZ-2 achieved its primary endpoint, with a statistically significant improvement in cardiac index (the amount of blood pumped by the heart per minute/body surface area). Genentech and Actelion signed a U.S. co-promotion agreement for Veletri in February 2000.

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. Tracleer™ (bosentan) and Veletri, 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, Alzheimer's 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.

# # #