Fitzy and others,
Unfortunately I haven't seen the full study. The reference popped up when I was doing a search for something else and I posted it thinking it might be of interest. I'll add an update at a later date whenever I have had a chance to take a look (I don't have easy access to this particular journal). As near as I can judge from the abstract (with the reservation that abstracts can be very misleading), it seems as if they may have started a small study, seen a trend toward improvement associated with use of Pentasa, and decided to increase the size of the study by enrolling additional patients to see if the trend reached statistical significance. But with a larger study population, it appears that the trend turned out to be simply a chance finding (which can occur, particularly with small study populations), and Pentasa was not superior to the placebo.
As to why it seems to help some people with Crohn's, who knows. Perhaps it works better for people whose disease is more similar to ulcerative colitis, since that is the FDA-approved indication for the drug and presumably it was proven more effective than placebo for people with UC. Regarding the speculation raised in the thread that attacks on Pentasa have been spurred by desire to stimulate sales of the biologic drugs, I don't think that works out from a chronological standpoint. The debate about whether the 5-ASA drugs are useful for Crohn's, not just ulcerative colitis, has been going on for years, as has the research attempting to settle the matter one way or the other. Excluding the present study from 2009, I know of 11 placebo-controlled studies of Pentasa. All but one were published between 1992 and 1997 (most in the early 90s), with remaining study published in 2000. The first biologic drug for Crohn's, Remicade, wasn't approved until 1998. I apologize if I upset anyone by posting the abstract, I just find it interesting to keep an eye on new research about Crohn's.