P453 Comparison of therapeutic effects between groups of thiopurine alone and combination of thiopurine with 5-ASA after remission introduced by oral tacrolimus for patients with severe ulcerative colitis

T. Sato1, K. Kojima2, R. Koshiba2, K. Fujimoto2, M. Kawai2, K. Kamikoduru2, Y. Yokoyama2, T. Miyazaki2, K. Watanabe1, N. Hida2, S. Nakamura2

1Department of Intestinal Inflammation Research, Hyogo College of Medicine, Nishinomiya, Japan, 2Department of Inflammatory Bowel Disease- Division of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan

Background

Although thiopurine is recommended to be used for maintenance after remission, the reliable data of maintenance introduced by tacrolimus is limited for patients with ulcerative colitis (UC). 5-aminosalicylic acid (5-ASA) is reported to induce 6-thioguanine nucleotides (6-TGN) levels higher in patients with inflammatory bowel diseases. However, the data of 5-ASA are few reported among East Asians.

Methods

A retrospective cohort study was conducted evaluating the 70 patients with severe UC who were primary responders to oral tacrolimus from April 2015 to March 2018. Twenty-seven patients were administered maintenance treatment with thiopurine. We evaluated the efficacy of thiopurines with and without 5-ASA in these patients, using ΔMCV, lowest WBC, highest 6TGN between groups of thiopurine alone and thiopurine+ 5-ASA. Kaplan–Meier analysis was used to assess time to relapse between groups of thiopurine and thiopurine+5-ASA.

Results

The median follow-up period was 430 days (interquartile range 207–952 days). The statistical significances were not found in patients background between groups of thiopurine and thiopurine+5-ASA. ΔMCV were significantly greater (p < 0.01), lowest WBC were significantly lower (p = 0.02) in the thiopurines+5-ASA group than in thiopurines alone group. The highest 6-TGN levels tended to be higher in thiopurine+5-ASA group than in thiopurine alone group (p = 0.09). The rate of relapse was significantly higher in the thiopurine alone group than in thiopurines+5-ASA group (p = 0.03). Kaplan–Meier curves confirmed that thiopurine+5-ASA group appeared to protect against relapse (log-rank test, p < 0.01).

Conclusion

Thiopurine+5-ASA induced significantly lower relapse than thiopurine alone after remission introduced by tacrolimus in the patients with severe UC, along with significantly greater the ΔMCV and lower the lowest WBC.