Eficácia e segurança da azatioprina no tratamento de longo prazo de pacientes com colite ulcerativa córtico-dependente

Abstract

Ulcerative colitis (UC) is a lifelong, immune-mediated inflammatory condition of the colonic mucosa, which is characterized by a relapsing and remitting course. Corticosteroids remain one of the most effective therapies for inducing remission in patients with moderate-to-severe UC. Nonetheless, corticosteroids are not used in maintenance therapy, mainly because undesirable side effects outweigh the possible benefits. Furthermore, approximately 25% of the patients is unable to support its withdrawal without relapsing, suggesting that the need to start steroid therapy in UC is associated with a dismal long-term prognosis. Thus, corticosteroid dependence in patients with UC is a pivotal clinical problem and maintenance of steroid-free remission is an important current evolving treatment goal. Patients with steroid dependent UC are usually given a choice between colectomy or stepped-up medical treatment, which traditionally involves prescription of an immunosuppressive drug. Azathioprine (AZA) therapy has found widespread use for this setting in clinical practice. However, studies assessing the efficacy of azathioprine in steroid-dependent ulcerative colitis (SD-UC) are scarce. The purpose of this trial was to explore the efficacy and safety of AZA in maintaining long-term steroid-free remission in SD-UC patients and the factors associated to sustained response. 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. 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-ASA use. Only disease duration <36 months was associated to off-steroids remission (P=0.02, OR 3.12 95% CI 1.89-7.64). The AZA benefit-risk profile was favorable. 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. This appears to sustain until 36 months.