P666 Neutropenia in inflammatory bowel disease patients on TNF inhibitors: A single-centre, retrospective cohort study

Abstract

Background Tumor necrosis factor-α inhibitors (TNFi) have become the mainstay of treatment in moderate to severe cases of IBD. The haematological safety profile of these agents has been documented in multiple clinical trials and post-marketing registries. Nonetheless, neutropenia has been reported in patients receiving TNFi for IBD and other diseases (Bessissow et al 2012). In this study, we aim to ascertain the relationship between the use of TNFi and the development of neutropenia in IBD patients. Methods This is a retrospective cohort study including all adult IBD patients receiving TNFi at our centre from the year 2007 to 2018. Our primary outcome was the development of any neutropenic episode after starting a TNFi. Neutropenia was defined as circulating absolute neutrophil count (ANC) less than 1500/mm3. For our secondary outcomes, we evaluated the impact of concomitant use of (5-ASA) or an immunomodulator on the risk of developing neutropenia. We also looked at the effect of baseline neutrophil and WBC counts on the subsequent development of neutropenia. Results A total of 292 patients met the inclusion criteria, 11 patients were excluded for not having neutrophil count done. The final analysis included 281 patients. The mean age of patients in this study was 33. Adalimumab was the most frequently prescribed TNFi. Of those included, 96 patients (34.2%) developed at least one episode of neutropenia while on a TNFi. The majority of these episodes (67.7%) were mild with ANC between 1000 and 1500/mm3. There was no significant difference in the age, gender, agent used or type of IBD between those who developed neutropenia and those who did not. On the other hand, baseline neutrophil count and concomitant use of azathioprine and 5-ASA were significant independent predictors of neutropenia after commencing TNFi. (Table 1). Conclusion In this study, mild neutropenia was common amongst IBD patients on TNFi. Patients were more likely to develop neutropenia if they have been on concurrent therapy with an immunomodulator or 5-ASA. Future prospective studies are required to further clarify the significance of neutropenia in IBD patients receiving TNFi.