Background: Data on the value of therapeutic drug monitoring of infliximab (IFX) to predict mucosal healing (MH) in inflammatory bowel diseases (IBD) are scarce.
Methods: All consecutive patients with IBD receiving ongoing IFX (5 mg/kg) treatment and developing secondary failure to IFX were enrolled in a prospective study between June 2010 and May 2011. IFX trough levels, antibodies to IFX concentrations, C-reactive protein levels, and fecal calprotectin were measured before IFX optimization and at week 8. A proctosigmoidoscopy was performed on the day of first IFX optimization and at week 8 in all patients with ulcerative colitis (UC). MH was defined by fecal calprotectin <250 μg/g stools in Crohn's disease (CD) and by an endoscopic Mayo score of 0 or 1 in UC.
Results: This study included 52 patients with IBD: 34 patients with CD (mean Crohn's Disease Activity Index, 300; mean C-reactive protein, 28 ± 10 mg/L; mean fecal calprotectin, 705 ± 300 μg/g) and 18 patients with UC (mean Simple Clinical Colitis Activity Index, 7; mean Mayo endoscopic score, 3). After IFX dose intensification, half of CD and UC patients achieved MH. Increase in IFX trough levels (called “delta IFX” in micrograms per milliliter) was associated with MH in both CD and UC (P = 0.001). A delta IFX >0.5 μg/mL was associated with MH (sensitivity [se], 0.88; specificity [sp], 0.77; P = 0.0001, area under the receiver operating characteristic curve, 0.89). On multivariate analysis, the only factor associated with MH after IFX optimization was a delta IFX >0.5 µg/mL (likelihood ratio = 2.02; 95% confidence interval, 1.01–4.08; P = 0.048) in patients with IBD.
Conclusions: Therapeutic drug monitoring of IFX strongly predicts the likelihood of achieving MH following IFX dose intensification in both CD and UC.
Article first published online 5 September 2013
*Immunology and Immunomonitoring Department, Laboratoire d’Immunologie et d’Immunomonitoring, CHU de Saint-Etienne, Saint-Étienne, France;
†Service de Gastrologie-Entérologie-Hépatologie, CHU de Saint-Etienne, Saint-Étienne, France;
‡Service de Rhumatologie, CHU de Saint-Etienne, Saint-Étienne, France; and
§Service de Gastroenterologie, CHU Nancy, Nancy, France.
Reprints: Xavier Roblin, MD, PhD, Department of Gastroenterology, CHU de Saint-Etienne, 42023 Saint-Etienne, France (e-mail: firstname.lastname@example.org).
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.ibdjournal.org).
L. Peyrin-Biroulet, lecture and consulting fees from Merck; X. Roblin, lecture and consulting fees from Merck and Theradiag. The other authors have no conflicts of interest to disclose.
Received July 09, 2013
Accepted July 30, 2013