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P348. Serum infliximab levels and early mucosal healing in Crohn's disease

J. Tang, X. Gao, M. Zhi, H. Zhou, H. Chen, M. Zhang, Q. Yang, Z. Liang, The Sixth Affiliated Hospital of Sun Yat-sen University, Department of Gastroenterology, Guangzhou, China

Background

Rare data have reported the value of serum infliximab (IFX) levels to predict early mucosal healing (MH) in Crohn's disease (CD). We designed this study to clarify the relationship among serum IFX levels, mucosal healing and clinical outcome in patients with CD after 3 shots of IFX [1,2].

Methods

A total of 15 diagnosed CD patients enrolled. None of them had experience of biological agents. Six of 15 patients received AZA/6-MP combination therapy. Endoscopy was performed at 10thweek after 3 shots of IFX, and mucosal healing was defined as no ulcer or major lesion. Serum infliximab level and anti-IFX antibodies (ATIs) were determined by immunoassays in the meantime.

Results

At week 10, mucosal healingwas found significantly correlated with serum IFX levels (P = 0.02) and hs-CRP (high sensitive C-reactive protein) levels (P = 0.03), but negatively correlated with anti-IFX antibodies (P = 0.08) and ESR (erythrocyte sedimentation rate) (P = 0.06). IFX levels were significantly high in the mucosal healing (MH) group (P = 0.03), while hs-CRP (P = 0.04) and ESR levels (P = 0.05) were significantly high in the non-mucosal healing group.

Receiver operation curve revealed that the optimal cutoff value of IFX levels for identifying mucosal healing was 4.87 mcg/ml (sensitivity 0.88; specificity 0.77, P = 0.03, area under the receiver mucosal healing 0.87).

Combination of thiopurine treatment at the very beginning benefited mucosal healing (P = 0.04), but did not affect serum IFX levels (P = 0.27) and ATI levels (P = 0.30).

Figure 1. Serum infliximab levels in mucosal healing (MH) and nonmucosal healing (NMH) group (P = 0.03).

Figure 2. Receiver operating characteristic (ROC) curve of IFX levels for identification of mucosal healing.

Conclusion

High serum level at induction stage of infliximab may promote mucosal healing. AZA/6-MP combination therapy at the very beginning may benefit early mucosal healing, but not affect serum IFX levels and ATI levels.

1. Stephane Paul, Emilie Del Tedesco, Hubert Marotte, et al. (2013), Therapeutic Drug Monitoring of Infliximab and Mucosal Healing in Inflammatory Bowel Disease: A Prospective Study, Inflammatory Bowel Disease.

2. Filip Baert, Maja Noman, Severine Vermeire, et al. (2003), Influence of Immunogenicity on the Long-Term Efficacy of Infliximab in Crohn's Disease, The New England Journal of Medicine.