Long-term results with azathioprine therapy in patients with corticosteroid-dependent Crohn's disease: Open-label prospective study

Background: A substantial number of patients with Crohn's disease (CD) become dependent on steroids after induction therapy. Treatment with azathioprine (AZA) may be beneficial in such patients. The present open-label study evaluated the long-term safety and efficacy of AZA in steroid-dependent CD patients. Methods: Adult patients with steroid-dependent CD were enrolled for AZA therapy over a 7-year period. The average dose of AZA was 2.0-3.0 mg/kg per day, adjusted according to clinical response and occurrence of adverse effects. Steroid therapy was tapered off according to a predefined schedule. Long-term outcome and adverse reactions were evaluated. Results: Sixty-nine patients were prospectively included. Steroid-free remission was achieved in 68-81% of patients, partial response in 14.5-27.3% and failure to respond to AZA in 4-15.9% over the initial 48 months. However, the rate of wean from steroid therapy decreased to 53-60% while the rate of failure increased from 6.7% to 17.6% after this period. A breakthrough of symptoms during continuous AZA therapy was common, particularly after 48 months on AZA. The mean leukocyte count at the end of 12 months of therapy was significantly lower in patients who achieved complete response on AZA than in the non-responders (5197 +/- 1250 cells/mm(3) vs 8340 +/- 1310 cells/mm(3), respectively; P < 0.01). Azathioprine was relatively well-tolerated and the incidence of serious adverse effects was small. Conclusions: Azathioprine was relatively safe and moderately effective for long-term maintenance of steroid-free clinical remission in corticosteroid-dependent CD patients. Patients were more successfully weaned from prednisone treatment, and clinical remission was more often maintained during the first 48 months of AZA therapy. A significant decrease in the white blood cell count at the end of 12 months on AZA was the single factor associated with weaning from steroid dependence.