Factors affecting the efficacy of cyclosporin A therapy for refractory ulcerative colitis

Background and Aims: Cyclosporin A (CSA), an immunosuppressive agent, is highly efficacious in patients with refractory ulcerative colitis (UC). We retrospectively investigated patients with refractory UC treated with CSA therapy to elucidate the efficacy and the prognostic factors. Methods: Forty‐one patients (26 men and 15 women) were enrolled. The efficacy of CSA was assessed at three time points: short‐ and mid‐term assessments took place 2 weeks and 1 year after CSA administration, respectively, and long‐term assessments at the end of the observation period. Results: The short‐term response rate was 71%. Background analysis revealed risk factors for CSA unresponsiveness: (i) more than 10 000 mg of prednisolone used before CSA treatment; (ii) the presence of circulating (C7‐HRP); and (iii) disease duration more than 4 years. The mid‐term relapse‐free survival rate was 51.0%. The addition of azathioprine (AZA) after CSA treatment significantly suppressed the incidence of relapse at 1 year (72.5% vs 26.7%, P = 0.0237). The overall colectomy‐free survival rate was 46.4%, and the induction of AZA after CSA treatment significantly reduced the colectomy rate (66.7% vs 30.5%, P = 0.0419). Among CSA responders, AZA naïve patients had significant lower‐probabilities for colectomies compared to patients with prior AZA treatment (22.5% vs 56.7%, P = 0.0309). The administration of CSA was discontinued in five cases. Conclusion: Our results revealed factors affecting the efficacy of CSA therapy for patients with refractory UC. AZA is an important agent that maintains disease quiescence once one responds to CSA. However, refractory patients despite AZA treatment are more likely to have consequent colectomies.