Abstract
BACKGROUND: Therapeutic drug monitoring involves therapeutic modifications based on the measurement of drug levels and antidrug antibodies. The viability of therapeutic drug monitoring in vedolizumab-treated patients with inflammatory bowel disease remains questioned. MAIN BODY: Accumulating evidence from clinical trials and real-world data suggests that an exposure-efficacy relationship may exist for vedolizumab in inflammatory bowel disease, but results are not as straightforward as they are for anti-tumour necrosis factor-α therapy. Robust target vedolizumab trough levels are currently missing, since available data are heterogenous and prospective, interventional pharmacokinetic-pharmacodynamic studies are lacking. The positioning of vedolizumab drug monitoring in therapeutic algorithms is yet to be defined. CONCLUSION: Therapeutic drug monitoring has the potential to improve the outcome parameters of vedolizumab-treated patients with inflammatory bowel disease. Before the therapeutic drug monitoring of vedolizumab can be implemented in a widespread fashion, prospective studies are needed to evaluate the effect of vedolizumab dose optimisation. These studies should focus on objective disease markers and vedolizumab drug levels, and define thresholds for optimal drug exposure.