Treatment success will be defined as a complete response to therapy at the end of eight weeks. Complete response (remission) will be defined as a reduction of the CDAI score to below 150 points with a reduction of at least 70 points from baseline. Partial response (improvement) will be analyzed as a secondary outcome measure and will be defined as a reduction of the CDAI score by 70 points or more but with a final value of 150 points or greater. Patients who experience a persistent rise in their CDAI scores of 100 points or more on two consecutive visits or a rise in their CDAI score to 400 points or more at any visit will be considered to be treatment failures and will be withdrawn from the study.