Liefferinckx C, et al. - Via retrospectively identifying patients switching from infliximab to vedolizumab, researchers analyzed the impact of two different wash-out periods [defined as the time between the discontinuation of one biologic and the initiation of a second biologic] on the pharmacokinetics of vedolizumab and infliximab. According to wash-out period, the population was divided into two groups: <6 weeks or >6 weeks. There were a total of 71 patients with inflammatory bowel disease. The presence of residual infliximab does not appear to influence the pharmacokinetics of vedolizumab. No differences in efficacy were observed, suggesting that prior switching from infliximab to vedolizumab may not be taken into account for the wash-out period. No significant safety differences were observed, but a higher number of infections in the event of a shorter wash-out period suggests that other safety-dedicated studies are needed. Overall, the investigators suggested that when switching infliximab to vedolizumab, clinicians may not need to be concerned about the impact of the wash-out period on second-line biologic pharmacokinetics.