A significant proportion of patients with initial response to Inflximab (IFX), subsequently lose response (LOR). Multicentre paediatric studies report LOR in 33% to 50% with 3–5 year follow-up. Our retrospective study examined durability of response and predictors of LOR.
From our IBD database of 185 children with CD, 65 received IFX maintenance therapy for luminal or fistulising Crohn's disease between January, 2006 and April, 2013. 47 with luminal CD ≥ 1 year follow-up after commencing IFX were included. We evaluated variables associated with response and describe outcomes on those remaining on IFX at four time points; before IFX, after induction, at 1 year and at the last follow-up. Response was divided into sustained primary, recovered, durable (combined sustained primary and recovered) and complete LOR (discontinuation from LOR or intolerance).
Overall, 28/47 (60%) children sustained primary response over a median duration of 2.83 years (1.6–4.4, IQR). 19/47 (40%) developed LOR (including 2 intolerant) at a median of 11 months (9–19, IQR). Of 17 with LOR, 7 were successfully re-induced giving durable response (35/47, 74%); 6 failed dose intensification needing surgery (n = 2), second anti-TNF (n = 2) or both (n = 2). 4 had surgery without dose intensification.
LOR was associated with low BMI at diagnosis, lower height Z scores prior to induction, elevated CRP following induction (p = 0.007) and failure to use concomitant IM (p = 0.02).
The cumulative probability of durable response to IFX in luminal CD was 83%, 74% and 70% after 1, 2, and 3 years on IFX maintenance therapy.