Five-year Safety Data From ENCORE, a European Observational Safety Registry for Adults With Crohn's Disease Treated With Infliximab [Remicade®] or Conventional Therapy

Background and Aims: The ENCORE registry aimed at comparing the long-term safety of Crohn's disease [CD] treatment with infliximab [Remicade®] and with conventional therapies in real-world clinical practice.

Methods: The 5-year, prospective, observational ENCORE registry followed patients with CD in nine European countries, who received treatment with infliximab, conventional therapies, or switched to infliximab from conventional therapy. Adverse events [AEs] in pre-specified categories and serious AEs were recorded at least every 6 months of the 5-year observation period. Frequency of events was evaluated, and multivariable analyses using follow-up time [Cox proportion hazards model] and exposure time [Poisson regression] were used to identify risk factors for time to AEs in pre-specified categories.

Results: Patients who received infliximab [N = 1541], conventional therapies [N = 1121], or switched to infliximab [N = 298] were followed for medians of 60.4, 55.6, and 42.5 months, respectively. Infliximab median exposure was 18.7 and 19.3 months in the infliximab and switched-to-infliximab groups, respectively. In time-to-event Cox proportion hazards [PH] analyses adjusting for confounders, infliximab [vs conventional therapy] was associated with serious infections (hazard ratio [HR] = 1.64, 95% confidence interval [CI]: 1.17, 2.31] and haematological conditions [HR = 2.91, CI: 1.51, 5.59], and not associated with lymphoproliferative disorders/malignancy [HR = 1.44, CI: 0.86, 2.42] or death [HR = 1.22, CI: 0.63, 2.36]. Prednisone use was associated with higher mortality [HR = 3.58, CI: 1.49, 8.61]. In exposure-adjusted Poisson regression analyses, infliximab was associated with lower mortality (risk ratio [[RR] 0.39, CI: 0.17, 0.88]).

Conclusions: Data from 5-year safety follow-up of patients with CD in the ENCORE registry demonstrate that infliximab [Remicade®] exposure is associated with increased risk of serious infections and haematological conditions, whereas mortality may be decreased.