Mesalamine in Crohn disease

Dr John Marshall is a professor and director in the Division of Gastroenterology at McMaster University and editor in chief of the Journal of the Canadian Association of Gastroenterology.

What is the role of mesalamine (international nonproprietary name mesalazine) in the management of Crohn disease? Can it be used as the only maintenance drug, or rather should it be a part of combination treatment?

John Marshall, MD, MSc: 5-aminosalicylic acid (5-ASA) has a long history in our management of inflammatory bowel disease. If you think back historically, this was a derivative of sulfasalazine, which is a dimer of sulfapyridine and 5-ASA. It was 40 years ago that we realized, somewhat fortuitously, the efficacy of 5-ASA for treatment of inflammatory bowel disease.

However, in Crohn disease I think the evidence is a bit difficult to interpret. In the 1970s, we did have the large National Cooperative Crohn’s Disease Study that showed efficacy for sulfasalazine in treating Crohn disease as an induction and early maintenance agent, which is useful, but when you look at the 5-ASA products and their efficacy in Crohn disease, it is much more difficult to show efficacy.

In fact, in the Cochrane review that looked at 5-ASA as a maintenance therapy in Crohn disease, we had an odds ratio of 1.0. It is a poor result showing no efficacy as a maintenance therapy. That is, I think, frustrating for clinicians because 5-ASA is a very easy therapy to give, very well tolerated, and relatively inexpensive, so of course it is still fairly commonly used in Crohn disease. I think there may be a subset of patients who respond to 5-ASA.

I will point out that a large trial is underway in Canada called the STATIC trial, which is randomizing patients who are doing well on 5-ASA—they either continue or stop, and those are patients with Crohn disease—so maybe we will identify a subset that responds. But if you look critically at the evidence, there is really no sign that 5-ASA is effective for Crohn disease. There may be a role for sulfasalazine and if you go back to those old trials that may be a subset of patients with mild colonic distribution of Crohn disease, but otherwise it is a therapy we do not use.