Efficacy of Sustained Combination Therapy for at Least 6 Months with Thiopurines and Infliximab in Patients with Ulcerative Colitis in Clinical Remission: A Retrospective Multicenter French Experience

Background and Aims: Long-term benefits of combination therapy (combotherapy) with infliximab (IFX) and azathioprine (AZA) have been less studied in ulcerative colitis (UC) than in Crohn's disease. The aim of the present study was to determine UC disease activity in patients who received at least 6 months of combotherapy, and whether cotreatment for more than 6 months was useful in these patients. Methods: A retrospective multicenter study was conducted in seven French academic centers from January 2010 to September 2012, including all UC patients having received at least 6 months of combotherapy in prolonged remission off steroids. During the follow-up period, which was divided into trimesters, scheduled IFX was continued as maintenance and AZA could be withdrawn. Assessment of UC activity by trimester was based on the following events: disease relapse defined by clinical relapse requiring a change of treatment, IFX failure, and colectomy. Results: Eighty-two patients were included (mean age 38 years; male: female ratio 1: 1) and followed up for a median of 22.3 +/- 14.0 months. Comparing 393 trimesters of combotherapy with 282 trimesters of IFX alone, fewer clinical relapses were observed with combotherapy (p = 0.049). Similar results were observed for IFX failure (p = 0.048). No difference was observed for colectomy. Duration of combotherapy longer than 9 months was inversely associated with clinical relapse (hazard ratio = 0.32 [95% confidence interval 0.15-0.70]). Conclusions: UC patients treated with combotherapy should maintain IFX and AZA for at least 9 months. Further studies are required to determine the optimal duration of combotherapy before stopping AZA in this situation.