Therapeutic drug monitoring in inflammatory bowel disease

PURPOSE OF REVIEW: This review provides an updated overview on the role of therapeutic drug monitoring (TDM) of biological therapies in IBD. We examine the data behind TDM for the anti-tumor necrosis factor (anti-TNF) agents, vedolizumab and ustekinumab, in patients with inflammatory bowel disease (IBD). In addition, we discuss reactive vs. proactive TDM. RECENT FINDINGS: There is a positive correlation between biologic drug concentrations and favorable therapeutic outcomes in IBD, although the majority of data refer to anti-TNF therapy. Reactive TDM has rationalized the management of patients with IBD with loss of response to biological therapy. Moreover, reactive TDM of infliximab has been proven to be more cost-effective when compared to empiric dose optimization. Preliminary data suggest that proactive TDM of infliximab and adalimumab applied in patients with clinical response/remission is associated with better therapeutic outcomes compared to standard of care (empiric treatment and/or reactive TDM). SUMMARY: For all biologics in IBD, there is a positive correlation between drug concentrations and favorable therapeutic outcomes. Reactive TDM is the new standard of care for optimizing biologic therapies in IBD, while recent data suggest an important role of proactive TDM for optimizing anti-TNF therapy in IBD.