As knowledge of the overactive immune response becomes clearer, the treatment of inflammatory bowel disease (IBD) continues to evolve rapidly from the use of anti-inflammatory agents to the use of immunomodulatory agents. A wide variety of medications have been shown to be effective in both uncontrolled and controlled trials in either or both ulcerative colitis and Crohn’s disease.1 These include 6-mercaptopurine (6-MP), azathioprine, methotrexate, cyclosporine,2 tacrolimus, interleukin 10, ISIS 2302, and infliximab (a monoclonal antibody against tumour necrosis factor α).

In this issue (see page 625) a randomised trial reports that treatment with mycofenolate mofetil (MMF) plus steroids was as effective as the combination of azathioprine plus steroids in obtaining a clinical response in chronic active Crohn’s disease. The study further suggests that onset of remission was more rapid in those patients with highly active disease and that there were few adverse side effects.

6-Mercaptopurine and its parent drug azathioprine are currently the agents of choice for the treatment of Crohn’s disease (and in my experience, for ulcerative colitis as well). Several enzyme systems convert 6-MP to either inactive metabolites or to the 6-thioguanine nucleotides which are purine antagonists and inhibit synthesis of …