Many reports indicate that a high-serum trough level of anti-tumor necrosis factor (TNF) agents is required for sustained remission in patients with Crohn's disease The pharmacokinetics of anti-TNF agents in inflamed intestinal tissue, however, is not well investigated. We investigated the association between the tissue concentration of anti-TNF agents and long-term disease outcome.
This was a prospective single-center study that enrolled 25 patients with Crohn's disease who were administered infliximab or adalimumab. All participants underwent endoscopy 2 weeks after administration of the anti-TNF agents, and biopsy samples were obtained from both inflamed and noninflamed intestinal tissue. Tissue concentrations of anti-TNF agents were evaluated and the correlation with serum trough levels was compared. The relation between the tissue drug concentration and clinical course over 24 months was also investigated.
Concentrations of anti-TNF agents were significantly higher in inflamed tissue than in noninflamed tissue. Patients with high-serum trough concentrations of anti-TNF agents had significantly higher drug levels in the noninflamed tissue than those with low-serum trough concentrations, but no difference in the levels was detected in the inflamed tissue. Patients with high-drug levels in the noninflamed tissue had a significantly higher sustained response rate than patients with low-drug levels.
Concentrations of anti-TNF agents in the noninflamed tissue can reflect sustained remission and may be a useful biomarker for monitoring therapeutic intensity in patients with Crohn's disease treated with anti-TNF agents (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/IBD/B623).