Is Proactive Therapeutic Drug Monitoring Ready for the Spotlight in Inflammatory Bowel Disease? Follow the Data.

As a plethora of data emerges on therapeutic drug monitoring (TDM) of biologics in inflammatory bowel disease, guidance on its application is needed. In this literature review and consensus statement, the authors recommend reactive TDM for all biologics, summarize concentration targets, and provide guidance on TDM in various scenarios. Proactive TDM with tumor necrosis factor-antagonist monotherapy is recommended as an alternative to the combination of tumor necrosis factor-antagonists with immunomodulators. Although observational data support this approach, randomized controlled trials do not. We argue that there is considerable work left to be performed before embracing proactive TDM as an equivalent alternative to combination therapy in inflammatory bowel disease.