Abstract
BACKGROUND AND AIMS: The role of therapeutic drug monitoring (TDM) 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 and endoscopic remission.
METHODS: Following 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 clinical remission (CR) and endoscopic remission (ER). Pooled mean differences (MDs) were estimated using random-effects models with restricted maximum likelihood estimation; heterogeneity was quantified using I2 statistic.
RESULTS: Twenty-three studies (6,753 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% CI 2.75-6.98; p < 0.0001; I2 = 0.0%). Higher concentrations were also associated with CR in UC (MD 3.18 μg/mL; p = 0.025) and CD (MD 3.08 μg/mL; p < 0.0001), although these clinical-remission estimates were statistically heterogeneous; no association was observed for ER in CD (MD 1.40 μg/mL; p = 0.453). Pooled remission-associated concentrations were presented descriptively and supported maintenance targets of ≥13-15 μg/mL in UC and ≥10-12 μg/mL in CD.
CONCLUSIONS: Higher VDZ trough concentrations were associated with remission, most robustly for endoscopic remission 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 TDM can be recommended.
