Vedolizumab Trough Concentrations and Clinical and Endoscopic Outcomes in Inflammatory Bowel Disease: A Systematic...

The role of therapeutic drug monitoring in optimizing vedolizumab (VDZ) therapy for Crohn's disease (CD) and ulcerative colitis (UC) remains unclear. Prior evidence was limited by small sample size and heterogeneous endpoints. We synthesized the available evidence on the association of VDZ trough concentrations with clinical (CR) and endoscopic remission (ER).

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, we searched the literature from inception to April 2026 for studies reporting VDZ trough concentrations stratified by remission status in CD and UC. Outcomes were CR and ER. Pooled mean differences (MDs) were estimated using random-effects models with restricted maximum likelihood estimation; heterogeneity was quantified using the I² statistic.

Twenty-three studies (6753 patients) met inclusion criteria; 18 contributed to quantitative synthesis. Higher VDZ trough concentrations were strongly associated with ER in UC (MD, 4.86 μg/mL; 95% confidence interval, 2.75-6.98; P < .0001; I² = 0.0%). Higher concentrations were also associated with CR in UC (MD, 3.18 μg/mL; P = .025) and CD (MD, 3.08 μg/mL; P < .0001), although these clinical remission estimates were statistically heterogeneous; no association was observed for ER in CD (MD, 1.40 μg/mL; P = .453). Pooled remission-associated concentrations were presented descriptively and supported maintenance targets of ≥13 to 15 μg/mL in UC and ≥10 to 12 μg/mL in CD.

Higher VDZ trough concentrations were associated with remission, most robustly for ER in UC. As these associations are largely cross-sectional, they may reflect reverse causation rather than a dose-response relationship. Prospective interventional trials are required before proactive therapeutic drug monitoring can be recommended.