A controlled double blind study of azathioprine in the management of Crohn's disease. Double-blind withdrawal trial of azathioprine as maintenance treatment for Crohn's disease. A randomized, double-blind, controlled withdrawal trial in Crohn's disease patients in long-term remission on azathioprine. A controlled trial of azathioprine in Crohn's disease. National Cooperative Crohn's Disease Study: results of drug treatment. Postoperative maintenance of Crohn's disease remission with 6-mercaptopurine, mesalamine, or placebo: a 2-year trial. Controlled trial of azathioprine in Crohn's disease.
While immunosuppressive agents are used widely in the management of Crohn's disease, their efficacy has not been well established in randomised controlled trials. This study was designed to examine whether azathioprine increases remission rate when used in conjunction with a diminishing dose regimen of prednisolone over a period of 12 weeks. It further examined whether azathioprine offers any therapeutic advantage over placebo in the maintenance of remission in Crohn's disease over a period of 15 months. Sixty three patients with active Crohn's disease were treated with a 12 weeks diminishing dose of prednisolone and at the same time entered into a randomised, double blind 15 month trial of either azathioprine (2.5 mg/kg) or placebo. Remission rates between the two groups were compared at 12 weeks and at 15 months. There was no significant difference in the proportion of patients who had achieved and maintained remission by week 12 but at 15 months there was a highly significant difference in the proportion of patients in remission (42% receiving azathioprine v 7% receiving placebo), p = 0.001. Using life tables this beneficial effect was reflected as the difference in the median number of days on the trial (p = 0.02). There were significantly greater decreases over the trial period in the median erythrocyte sedimentation rate, C reactive protein, and leucocyte count in the azathioprine group. There were no cases of severe bone marrow suppression or clinical pancreatitis. In conclusion, azathioprine offers a therapeutic advantage over placebo in the maintenance of remission in Crohn's disease. 51 patients with Crohn's disease who were in good health while taking azathiprine, 2 mg/kg body-weight/day, for at least six months were allocated either to a group in which azathioprine was continued or to one in which a control tablet was substituted. The trial lasted one year unless relapse recurred earlier. The cumulative probability of relapse was nil at six months and 5% (+/-5 S.D.) at a year among those on azathioprine, compared with 25% (+/-9 S.D.) at six months and 41% (+/-11 S.D.) at a year among those in the control group (P less than 0.01). 1 patient in whom azathioprine was continued died of pancytopenia in the fourth month of the trial. Azathioprine is potentially toxic but appears to reduce the relapse-rate in Crohn's disease. An open study reported that patients with Crohn's disease in remission who have taken azathioprine for longer than 3.5 years are at low risk of relapse when azathioprine is discontinued. To confirm this observation, we performed a multicenter, double-blind, noninferiority withdrawal study.
                Patients who were in clinical remission on azathioprine for > or = 42 months were randomized to continue azathioprine or to receive an equivalent placebo for 18 months. The primary end point was clinical relapse at 18 months.
                Forty patients were randomly assigned to receive azathioprine and 43 to receive placebo. Characteristics of patients at entry were similar in the 2 study groups. At 18 months, 3 patients had a relapse in the azathioprine group, and 9 had a relapse in the placebo group. Kaplan-Meier estimates of the relapse rate at 18 months were 8% +/- 4% and 21% +/- 6%, respectively. The hypothesis that placebo was inferior to azathioprine was not rejected (P = .195). Among the baseline variables, C-reactive protein level > 20 mg/L, time without steroids < 50 months, and hemoglobin level < 12 g/dL were found to be predictive of relapse in the multivariate analysis.
                This study shows that azathioprine withdrawal is not equivalent to continued therapy with azathioprine for maintenance of remission in patients with Crohn's disease who have been in remission on azathioprine for > or = 3.5 years. Thus, azathioprine maintenance therapy should be continued beyond 3.5 years. To determine the efficacy of azathioprine in the treatment of Crohn's disease, a 26-week double-blind trial was performed. 20 patients with Crohn's disease, requiring at least 10 mg of prednisone/day over the 3 months prior to entering the study were randomized into placebo (10 patients) and major criterion of success in the trial. There were 7 relapses in the placebo group (5 patients) and 2 relapses in the azathioprine group (2 patients). Complications including fistulae were not affected by the medications. The mean reduction in steriod dosage in the azathioprine group at the end of the trial (-15.5 mg) was greater than in the placebo group (-6.1 mg). These results suggest that azathioprine may permit reduction or discontinuation of steroids without the worsening of symptoms in some patients who appear to require steroids for control of their symptoms. The clinical features of this "AZA-responsive subgroup" remain to be defined. The response of active and quiescent Crohn's disease to prednisone, sulfasalazine, or azathioprine has been studied in 569 patients in a placebo-controlled, randomized, multicenter cooperative trial. The response of active symptomatic disease to prednisone or sulfasalazine was significantly better than to placebo. Response to azathioprine was better than to placebo, but the difference did not reach conventional levels of statistical significance. Patients with colonic involvement were especially responsive to sulfasalazine, and those with small bowel involvement were especially responsive to prednisone. Patients' drug therapy immediately before entry to the study significantly affected subsequent response. For patients with quiescent disease, none of the drugs was superior to placebo in prophylaxis against flare-up or recurrence. There is less than a 5% risk that a clinically significant prophylactic effect of any of the drug regimens was missed. No therapy has been shown to reliably prevent the evolution of postoperative recurrence of Crohn's disease. The aim of the current trial was to compare 6-mercaptopurine (6-MP) and mesalamine with placebo for the prevention of clinical, endoscopic, and radiographic recurrence of Crohn's disease after resection and ileocolic anastomosis.
                Five centers randomized 131 patients to receive 6-MP (50 mg), mesalamine (3 g), or placebo daily in a double-blind, double-dummy trial. Patients had clinical assessments at 7 weeks and then every 3 months; colonoscopy at 6, 12, and 24 months; and small bowel series at 12 and 24 months. End points were clinical, endoscopic, and radiographic recurrence rates at 24 months.
                Clinical recurrence rates (intent to treat) by life-table analysis at 24 months were 50% (95% confidence interval [CI], 34%-68%), 58% (95% CI, 41%-75%), and 77% (95% CI, 61%-91%) in patients receiving 6-MP, mesalamine, and placebo, respectively. Endoscopic recurrence rates were 43% (95% CI, 28%-63%), 63% (95% CI, 47%-79%), and 64% (95% CI, 46%-81%), and radiographic recurrence rates were 33% (95% CI, 19%-54%), 46% (95% CI, 29%-66%), and 49% (95% CI, 30%-72%), respectively. 6-MP was more effective than placebo ( P < 0.05) at preventing clinical and endoscopic recurrence over 2 years. Patient withdrawals resulted in 69% of the study population evaluable for the clinical recurrence end point.
                6-MP, 50 mg daily, was more effective than placebo at preventing postoperative recurrence of Crohn's disease and should be considered as a maintenance therapy after ileocolic resection. nan
Azathioprine and 6-mercaptopurine are more effective than placebo for maintenance of remission in Crohn's disease. Higher response rates were obtained with azathioprine than 6-mercaptopurine. However, the one study evaluating 6-mercaptopurine used a relatively low dose of the drug. Future studies should look at the effect of higher doses of 6-mercaptopurine. There is weak evidence for a steroid sparing effect with azathioprine treatment.