Therapeutic Drug Monitoring of Vedolizumab Levels During Maintenance in Inflammatory Bowel Disease (MOVE-IBD)

Therapeutic drug monitoring (TDM) of non anti-TNF biologics is not well established in clinical practice. We aimed to clarify the association between VTL and remission in our cohort of maintenance vedolizumab patients using objective markers of disease activity to see if this could aid in decision making.

A retrospective cross-sectional cohort study was performed on 83 consecutive moderate-severe inflammatory bowel disease (IBD) patients. VTL measurement immediately prior to infusion was paired with clinical and objective markers of disease activity. Objective disease assessment was undertaken using fecal calprotectin, magnetic resonance imaging, intestinal ultrasound, or sigmoidoscopy/colonoscopy.

Eighty-three patients on maintenance vedolizumab were evaluated (59% UC and 41% CD). The median age at diagnosis was 40 years. Median trough vedolizumab levels were comparable in patients who achieved steroid-free clinical remission (12.65 μg/mL vs. 8.89 μg/mL p = 0.771) or objective remission (15.22 μg/mL vs. 8.89 μg/mL p = 0.073) versus those who had not. Quartile analysis (Q1: < 6.9 μg/mL, Q2: 6.9-12.2 μg/mL, Q3: 12.2-18.6 μg/mL, and Q4: > 18 ug/mL) showed no difference between quartiles of vedolizumab levels and clinical or objective remission (p = 0.65).

Vedolizumab trough levels were not associated with clinical or objective remission during maintenance therapy, and in our real-world cohort, do not appear to be a clinically relevant target for TDM.