Background: Infliximab (IFX) is an effective rescue therapy for hospitalized steroid refractory acute ulcerative colitis (ASUC). Treatment response is associated with serum IFX trough levels. Intensified dosing regimens with escalated dose and/or shortened interval are increasingly used to compensate for the higher inflammatory burden and drug clearance. Our study aims to determine if intensified IFX induction regimen improves colectomy-free outcomes and identify predictors of long term outcomes.
Methods: A retrospective review was performed between July 2010 and May 2016 at McGill University hospitals. All hospitalized adult patients who received at least one infusion of IFX as rescue therapy for steroid refractory ASUC were identified through our pharmacy drug database. We compared standard inductions with 5mg/kg vs 10mg/kg as well as shortened induction interval (i.e. completion of induction within 4 weeks). The primary outcome was the colectomy rate at 2 years. Baseline clinical parameters and dosing regimen were explored with regression analysis.
Results: 72 patients (38% female, mean age 41) were identified. 37 patients (51%) received standard 5 mg/kg IFX induction and 35 received 10 mg/kg. 5 patients received shortened induction interval with IFX 10mg/kg. Baseline clinical parameters were well matched among various regimens. The 30-day and 2-year colectomy rate in our cohort was 6.9% and 15.2% respectively. 2-year colectomy-free survival was not significantly different between the standard (86.5%) and escalated (82.9%) dose IFX induction (p=0.388) whereas the shortened induction was associated with lower colectomy-free rate (40% versus standard induction 88.1%, p<0.001). Hemoglobin ≤90 g/L (OR 4.8 [95% CI: 1.2–19.1], p=0.03), albumin <30 g/L (OR 7.9 [95% CI: 1.5–40.1], p=0.01) and a short IFX induction regimen (OR 11.1 [95% CI: 1.6–76.6], p=0.015) were all associated with increased risk of colectomy at 2 years in univariate regression analysis. Albumin <30 g/L remained significant in multivariate modelling (p=0.03).
Conclusions: Use of intensified infliximab rescue therapy did not improve 2-year colectomy-free survival in this cohort. Tailored use in high risk patients such as those with low albumin and hemoglobin may be beneficial although this needs to be validated in prospective clinical trials.