6-Mercaptopurine is effective in Crohn's disease without concomitant steroids

Background: 6-Mercaptopurine (6-MP) has shown efficacy in the treatment of Crohn's disease when used in conjunction with corticosteroids. Sparse literature to date suggests that 6-MP is effective when used without steroids. We therefore studied the efficacy of 6-MP in corticosteroid-naive Crohn's patients. Methods: We conducted a retrospective chart review of 24 patients who were treated with 6-MP but had never received any form of steroid treatment at any time. 6-MP efficacy was assessed with serial modified Harvey-Bradshaw scores. In addition to overall response, data were also analyzed according to the indication for treating with 6-MP (disease activity, fistulae, or both). The time to relapse and the treatments required were also analyzed. Results: Overall, remission or significant improvement was seen in 20 patients (83% of original group). Seven patients (29%) achieved complete remission; another 13 patients (54%) demonstrated significant clinical improvement. By indication, 89% of patients treated for activity, 50% of patients treated for activity and fistula, and 100% of patients treated for fistula alone showed response. Drug effect required a median of 5.7 months to occur (for all patients: range, 1.7-37.9 months). Thirteen of the twenty patients who improved or remitted on 6-MP eventually relapsed, usually due to stopping 6-MP, at a median of 13.8 months (range, 0.9-57.8). Relapse was less frequent if patients continued 6-MP. Treatment of relapses required only antibiotics, and/or restarting 6-MP (or increasing the dose) in most patients. Conclusions: 6-MP is an effective medication for use in steroid-naive patients and is likely to be effective in patients who have received steroids in the past but are not currently receiving them. Relapses occur despite continued therapy, but are often easily treated, and do not require initiating steroids.