Infliximab Trough Levels Correlated with Remission in Luminal Crohn Disease

Higher infliximab trough levels were associated with clinical and endoscopic remission in patients with Crohn disease (CD), according to a substudy.

Higher infliximab trough levels were associated with clinical and endoscopic remission in patients with Crohn disease (CD), according to results from a substudy published in Clinical Gastroenterology and Hepatology.

A subset of data from TAILORIX (randomized controlled trial investigating tailored treatment with infliximab for active luminal Crohn disease) was used to study infliximab use in patients with active luminal CD. Researchers assessed baseline disease state and magnetic resonance entrerography (MRE) after 54 weeks of infliximab treatment in 36 individuals (median age 35.7 years, median disease duration 1.5 months) treated at 27 centers in Belgium, France, and the Netherlands. The MaRIA criteria was used to define radiologic response (score 7-11) and remission (score <7).

At 54 weeks, radiologic response was achieved in 36.4% of patients, remission in 30.3%, and endoscopic features of remission in 71%. The investigators observed a correlation between baseline MaRIA scores and CD endoscopic index of severity (κ=0.46; P =.008). This correlation was not observed at the study conclusion (κ=0.06; P =.75).

Infliximab trough levels were correlated with radiologic remission at week 14 (P =.049). An infliximab trough level of 7.8 μg/ml could predict radiologic remission with an area under the curve of 0.74 (75% sensitivity; 86% specificity). Radiologic response was similarly correlative at week 14 (P =.048) and predictive (area under the curve, 0.73; 70% sensitivity; 90% specificity).

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Patients demonstrated continuous pharmacologic evidence of response at an infliximab trough levels above 5.0 μg/ml over the course of the study duration (P =.034). At the study conclusion, the patients who received the highest infliximab trough levels had the highest radiologic response (P =.03) and remission (P =.06) rates.

The limitations of this study included the small sample size and large number of participating centers. Because the 36 patients underwent MRE at 5 centers, the MR equipment used to calculate the MaRIA scores varied, likely introducing inter-rater variability into these results.

The study authors concluded that infliximab exposure was correlated with radiologic remission and response in patients with active luminal CD.

Disclosures: Some authors declared receiving consulting or funding from the pharmaceutical industry. A complete list of disclosures can be found in the original study.

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Bossuyt P, Dreesen E, Rimola J, et al. Infliximab exposure associates with radiologic evidence of healing in patients with Crohn’s disease [published online April 28, 2020]. Clin Gastroenterol Hepatol. doi:10.1016/j.cgh.2020.04.052