Predictors of relapse following infliximab de‐escalation in patients with inflammatory bowel disease: the value of a strategy based on therapeutic drug monitoring

Summary Background There are limited data concerning infliximab drug monitoring during de‐escalation of the treatment of inflammatory bowel disease (IBD). Aim To define the rate and the predictors of relapse following infliximab de‐escalation in IBD patients in remission. Methods All IBD patients at a single referral centre in clinical and biological remission and in whom the dose of infliximab had been de‐escalated were included. Patients in remission with a high trough level of infliximab (>7 mg/L) were considered to be trough level‐based de‐escalation patients. The data were retrieved from a prospective IBD database. Actuarial analysis was performed for statistical purposes. Results A total of 146 de‐escalations were performed in 96 patients (Crohn's disease/ulcerative colitis: 68%/32%); 54 (37%) were based on clinical remission only, and 92 (63%) were based on clinical remission associated with a trough level above 7 mg/L. The cumulative probabilities of relapse following infliximab de‐escalation were 16% and 47% at 1 and 2 years, respectively. Ulcerative colitis was associated with an increased risk of relapse (HR = 3.2, P = 0.005). Conversely, combination therapy at infliximab initiation (HR = 0.39, P = 0.0110) and trough level‐based de‐escalation were associated with decreased risk of relapse (HR = 0.45, P = 0.024). Trough levels before and after de‐escalation were well correlated; a decrease by half was observed following a 2‐week interval increase or a half‐dose decrease. Conclusion The use of trough levels to assess the feasibility of dose de‐escalation seems to be a prerequisite for decreasing the risk of relapse.