Letter to the Editor
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 7, 2022; 28(13): 1380-1383
Published online Apr 7, 2022. doi: 10.3748/wjg.v28.i13.1380
Therapeutic drug monitoring in inflammatory bowel disease: At the right time in the right place
Brindusa Truta
Brindusa Truta, Internal Medicine, Johns Hopkins University, Baltimore, MD 21210, United States
Author contributions: Truta B performed literature review, analyzed data, wrote the letter.
Conflict-of-interest statement: No conflict of interest to declare.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Brindusa Truta, MD, Assistant Professor, Internal Medicine, Johns Hopkins University, 1830 E Monument Street, Room 426, Baltimore, MD 21210, United States. brindusa_73@yahoo.com
Received: October 30, 2021
Peer-review started: October 30, 2021
First decision: December 12, 2021
Revised: January 17, 2022
Accepted: February 27, 2022
Article in press: February 27, 2022
Published online: April 7, 2022

Therapeutic drug monitoring (TDM) was one of most sought-after objective tools to determine therapeutic efficiency of different biologics and its role in the management of patients with inflammatory bowel disease (IBD) was regarded with great anticipation. But implementation of the TDM in clinical practice was challenged by several factors including uncertainty of the optimal cut-off values, assay variable sensitivity in detecting drug levels and antibodies and, most importantly, individual pharmacokinetics. While reactive TDM was embraced in clinical practice as a useful tool in assessing lack of response to therapy, the utility of proactive TDM in managing IBD therapy is still challenged by the lack of consistency between evidence. Described here, there are four groups of IBD patients for whom proactive TDM has the potential to greatly impact their therapeutic outcomes: Patients with perianal Crohn’s disease, patients with severe ulcerative colitis, pregnant women with IBD and children. As the future of IBD management moves towards personalizing treatment, TDM will be an important decision node in a machine learning based algorithm predicting the best strategy to maximize treatment results while minimizing the loss of response to therapy.

Keywords: Therapeutic drug monitoring, Inflammatory bowel disease, Biologics, Crohn’s disease

Core Tip: While reactive therapeutic drug monitoring (TDM) was embraced in clinical practice as an important tool for assessing lack of response to biologics, existent evidence inconsistently supports the proactive use of TDM in managing inflammatory bowel disease (IBD) therapy. Exceptions are made for patients with severe ulcerative colitis and perianal Crohn’s disease (fistula) for whom TDM has consistently shown to improve clinical outcome, pregnant women with IBD for whom TDM has the potential to play a decisive role in withholding therapy and for children, for whom proactive TDM was found to increase steroid free clinical remission. Future studies are needed to define the real value of TDM in management of IBD.