Background: Studies assessing the efficacy of azathioprine (AZA) in steroid-dependent ulcerative colitis (SD-UC) are scarce. The purpose of this trial was to explore the efficacy of AZA in maintaining steroid-free remission in SD-UC patients and the factors associated with sustained response.
Methods: In this observational cohort study, 42 subjects with SD-UC were recruited for AZA therapy during a 3-year period. AZA was adjusted for a target dose of 2-3 mg/kg/day. Steroid therapy was tapered off following a standardized regimen. The primary endpoint was the annual rate of steroid-free response to AZA. Secondary endpoints included clinical recurrence, yearly steroid dose, and safety of treatment.
Results: On an intention-to-treat basis, the proportion of patients remaining in steroid-free remission at 12, 24, and 36 months was 0.55, 0.52, and 0.45, respectively. A significant decrease in the flare-ups rate and in requirement for steroids were observed during 3 years on AZA compared with the previous year (P = 0.000 for both). Patients with and without sustained response were comparable according to demographics, extent of disease, dose of AZA, steroids, and 5-aminosalicylate (5-ASA) use. Only disease duration <36 months was associated with off-steroids remission (P = 0.02, odds ratio [OR] 3.12, 95% confidence interval [CI] 1.89-7.64). The AZA benefit-risk profile was favorable.
Conclusions: In this open-label observational trial AZA showed sustained efficacy for maintenance of clinical remission off steroids and steroid sparing through 3 years of therapy in SD-UC. Patients with earlier UC are those who most probably will have sustained steroid-free remission at the end of 12 months while on AZA.