cA2 in Crohn's disease

A fair amount of press has recently been seen about a new cure for Crohn's disease. Unfortunately, this was very poor reporting. The drug that has garnered all this attention was called cA2, and now is named Infliximab.This drug is an antibody that binds an immune chemical called TNF-alpha.Antibodies are large proteins that can only be administered intravenously.The reports at the Digestive disease week meeting in San Francisco lastMay (May 1996) basically showed that in patients with severe Crohn's disease,65% percent had an excellent response to administration of cA2. Patientswith Ulcerative colitis were not helped. Patients relapsed as the drugwore off.

Thus, while not a cure, cA2 will probably be an important drug in the treatmentof Crohn's disease. It will probably find its role in the treatment ofpatients with Crohn's who are hospitalized for a severe flare. In thesepatients, the drug will probably allow faster control of the inflammation.The patients will still be treated with steroids, but the cA2 will allowfaster discharge. Interestingly, a lot of patients getting the drug at this time are patients who have been maintained as an outpatient who havebeen doing poorly with chronic fistulas or inflammation that has nevercome under control.

One aspect which has cause a lot of excitement in the scientific communityabout this drug is that it is one of the first success stories for immunologyresearch predicting clinical results. TNF-alpha is an early player in theimmune response, so blocking it should be effective. However, studies ofUlcerative Colitis patients showed that they do not have elevated levelsof TNF-alpha, while Crohn's patients do. Thus, the effectiveness of cA2in Crohn's but not in UC confirmed the immune studies in those patients.The research into what causes the lack of response in 35% of the Crohn'spatients will be interesting to follow.

Stephen Holland, M.D.
Section of Clinical Pharmacology
University of Illinois College of Medicine at Peoria

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