Maintenance Adalimumab Concentrations Are Associated with Biochemical, Endoscopic, and Histologic Remission in Inflammatory Bowel Disease.

BACKGROUND

A treat-to-target therapeutic approach is emerging as the new standard of care for treating inflammatory bowel disease (IBD), Crohn's disease (CD), and ulcerative colitis (UC).

AIMS

We aimed to investigate the association of serum adalimumab concentrations during maintenance therapy with biochemical, endoscopic, and histologic remission in IBD.

METHODS

This retrospective multicenter study included consecutive IBD patients on adalimumab maintenance therapy who had a C-reactive protein (CRP) within 1 week and/or endoscopic evaluation within 12 weeks of therapeutic drug monitoring between July 2013 and December 2016. Biochemical remission was defined as a normal CRP (≤ 5 mg/L). Endoscopic remission was defined as the absence of any ulceration/erosion or a Rutgeerts score of ≤ i1 for patients with an ileocolonic resection for CD and a Mayo endoscopic score of ≤ 1 for UC. Histologic remission was defined as the absence of any sign of active inflammation. Adalimumab concentrations were measured using the homogeneous mobility shift assay.

RESULTS

Ninety-one CRP levels and 72 colonoscopies from 98 IBD patients [CD: n = 72 (73%)] were evaluated. Based on receiver operating characteristic analyses, we identified an adalimumab concentration threshold of 11.8, 12, and 12.2 μg/mL in CD and 10.5, 16.2, and 16.2 μg/mL in UC to stratify patients with or without biochemical, endoscopic, or histologic remission, respectively. Adalimumab concentrations ≥ 12 μg/mL (OR 8; 95% CI 2-31.9; p = 0.003) and ≥ 12.2 μg/mL (OR 9.6; 95% CI 1.7-56.1; p = 0.012) were independently associated with endoscopic and histologic remission in CD, respectively.

CONCLUSIONS

This study demonstrates that higher maintenance adalimumab concentrations are associated with objective therapeutic outcomes in IBD.