A recent retrospective study (E Dreesen et al Clin Gastroenterol Hepatol 2018; 16: 1937-46) with 179 consecutive patients (66 with ulcerative colitis, and 113 with Crohn’s disease) found that vedolizumab (VDZ) trough concentrations were correlated with response.
- VDZ trough >30 mcg/mL at week 2, >24 mcg/mL at week 6, and >14 mcg/mL during maintenance were associated with effectiveness endpoints including endoscopic healing, physician global assessment and biochemical response (based on CRP).
- Median VDZ trough levels during induction were 27.7 mcg/mL at week 2, 27.4 mcg/mL at week 6. With standard dosing, the maintenance VDZ trough was 13.5 mcg/mL at week 14
- Higher BMI and more severe disease, based on CRP, albumin, and/or hemoglobin, were associated with lower VDZ trough levels and lower probability of mucosal healing (P<.05).
Interestingly, in the discussion the authors note that VDZ troughs above 3 mcg/mL completely saturate α4β7 intergrin. This physiologic phenomenon is hard to reconcile with data showing better response with higher VDZ levels. The authors note that “at present, there are not enough data in our study to support the role for TDM to guide clinical decision-making on dose escalation for vedolizumab.”
My take: This study implies that VDZ levels may help predict response but are not necessarily helpful in determining whether dose escalation is warranted.
Related blog posts: