A prospective cohort study to assess the relevance of Vedolizumab drug level monitoring in IBD patients

Background:

Vedolizumab drug monitoring strategies in IBD patients have not been investigated systematically so far. Our aim was to evaluate the correlation between vedolizumab trough levels (VTL) and the treatment response in IBD patients.

Methods:

51 patients with therapy-refractory ulcerative colitis (UC) (n = 23), Crohn's disease (CD) (n = 27) or indeterminate colitis (IC) (n = 1) on or starting a therapy with vedolizumab were enrolled. Disease activity indices, total blood count, albumine, ferritin, C-reactive protein (CRP), and anthropometric parameters were assessed over a time period of 6 months (155 VTL, liquid chromatography mass spectrometry (LC-MS/MS).

Results:

Vedolizumab treatment was found to be clinically effective. CD patients with a serum CRP level lower than 5 mg/l exhibited significantly higher VTL than those with elevated CRP levels (34.9 versus 21.7 µg/ml, p = 0.00153). UC patients with hemoglobin levels higher 12 g/dl had significantly higher VTL compared to patients with lower hemoglobin levels (35.4 versus 15.6 µg/ml, p < 0.0005). Statistical analyses indicate a significant association between VTL and treatment efficacy measured by CRP level in CD and hemoglobin level in UC (no effect of concomitant medication on VTL).

Conclusions:

Our data suggest a significant correlation between VTL and clinical response in IBD patients treated with vedolizumab.