Dutch biotechnology company Crucell N.V. (Euronext, NASDAQ: CRXL; Swiss Exchange: CRX) has today announced that it has decided to suspend further clinical development of Aerugen®, its vaccine candidate for the prevention of Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients.

The decision follows the results of a double-blind, randomized, placebo-controlled phase III trial involving 476 patients from 46 centers in four European countries. In the phase III clinical study, patients without P. aeruginosa colonization were vaccinated with Aerugen® or a placebo vaccine. The primary endpoint of the study was the prevention of colonization with one or more of the serotypes of P. aeruginosa in the candidate vaccine.

The result of this phase III study failed to confirm the efficacy results indicated in the earlier clinical study. Based on these results, the Company has decided to suspend further clinical development of the candidate vaccine. Safety results of the phase III study were in line with previous findings and did not show any clinically relevant safety issue.

Crucell said that discontinuation of this clinical development program does not impact the Company's revenue forecast for 2006, nor its earlier stated goal to achieve cash break-even in 2007.

About Cystic Fibrosis
CF is a life-threatening disease caused by a defective gene that leads to altered body fluid secretion by certain glands. Abnormally thick, sticky mucus develops, clogging the lungs and potentially resulting in fatal lung infections. Approximately 80% of CF patients become chronically colonized with P. aeruginosa in the lungs by the age of 18, resulting in an average life-expectancy of 33 years. In 80% of these cases, the bacteria are the cause of mortality.