A new study published in Inflammatory Bowel Diseases investigated the association between tissue concentration of anti-tumor necrosis factor (anti-TNF) agents and long-term disease outcome of Crohns Disease. This prospective single-center study enrolled 25 patients with Crohns disease who were administered infliximab or adalimumab, and underwent endoscopy 2 weeks thereafter. The results revealed that concentrations of anti-TNF agents were significantly higher in inflamed tissue than in non-inflamed tissue. In addition, patients with high-serum trough concentrations of anti-TNF agents had significantly higher drug levels in the non-inflamed tissue than those with low-serum trough concentrations. However, no difference in the levels was detected in the inflamed tissue. On the other hand, patients with high-drug levels in the non-inflamed tissue had a notably higher sustained response rate than patients with low-drug levels. Thus, it was concluded that concentrations of anti-TNF agents in non-inflamed tissue can reflect sustained remission and may be a useful biomarker for monitoring therapeutic intensity in patients with Crohns disease treated with anti-TNF agents.1Reference1. Yoshihara T, Shinzaki S, Kawai S et al. Tissue Drug Concentrations of Anti-tumor Necrosis Factor Agents Are Associated with the Long-term Outcome of Patients with Crohnʼs Disease. Inflammatory Bowel Diseases. 2017:1. doi:10.1097/mib.0000000000001260.