P753 Vedolizumab trough levels during induction in IBD patients: A longitudinal observational retrospective study

Abstract

BackgroundVedolizumab (VDZ) is effective for the treatment of ulcerative colitis (UC) or Crohn’s disease (CD). Few real-world experience data are available on the relevance of measuring trough levels (TLs) early on to predict loss of response in patients treated with VDZ. Our objective was to evaluate VDZ TLs early on at inductionMethodsIn total, 86 IBD patients (45 CD, 32 UC, 9 IBD unclassified) have been treated with VDZ. 400 samples were prospectively collected from September 2015 to August 2017 and measured retrospectively by Ridascreen VDZ ELISA in parallel with clinical, biological and endoscopic data. Induction analyses include second and third infusion; optional dose at week 10 not included. Treatment failure was defined by the need to optimise VDZ and/or to swap because of active disease. Sustained response was defined by clinical response without need of optimisation. Statistical analyses were performed using the Student t-test. Results were expressed as mean ± standard error.Results34% of patients (n = 29/86) stopped VDZ because of treatment failure during maintenance. The mean duration of VDZ treatment is shorter in patients experiencing treatment failure (145 days25 days) than patients with sustained response (263 days ± 27, p = 0.004). At the third infusion (week 6), the sustained response group had higher TLs (38.1 mg/ml ± 4.7) than the failure group (24.7 mg/ml ± 3.1) (p = 0.03) (Figure 1).Figure 1.View largeDownload slideSustained Response and Treatment Failure groups at third induction (week 6)Figure 1.View largeDownload slideSustained Response and Treatment Failure groups at third induction (week 6)but not at the second infusion (week 2) (36.3 mg/ml ± 2.35 vs. 29.7 mg/ml ± 2.94, p = 0.65). At induction, patients previously treated with anti-TNF had significant lower TLs (30.4 mg/ml ± 1.75) compared with anti-TNF naïve patients (35.5 mg/ml ± 2.3, p = 0.04) (Figure 2)Figure 2.View largeDownload slideAnti-TNF naïve and Anti-TNF previously exposed groups (week 2 and 6, optional dose at week 10 not included)Figure 2.View largeDownload slideAnti-TNF naïve and Anti-TNF previously exposed groups (week 2 and 6, optional dose at week 10 not included)There was significant more VDZ failure in patients previously treated with anti-TNF compared with anti-TNF naïve patients (24/63VS2/23, p = 0.008). Finally, 31% of the cohort (n = 27/86) had combo therapy with immunomodulators (IMM) but no difference was observed in terms of TLs at induction (29.9 mg/ml ± 2.7g with IMM vs. 31.7 mg/ml ± 1.7 without IMM, p = 0.5). There was not more VDZ failure without IMM than with IMM (18/59 VS. 11/27, p = 0.46)ConclusionsThis study suggests that patients who lose response to VDZ during maintenance have lower VDZ TLs at induction. VDZ TLs at week 6 (3nd infusion) seem to be the most indicative time point. The presence of IMM does not seem to impact TLs at induction or to generate a reduction of VDZ failure