Background: Vedolizumab, a gut-selective anti-integrin inhibitor is a biologic agent indicated for ulcerative colitis (UC) treatment. We retrospectively investigated whether improvement of serum C-reactive protein (CRP) levels, after the first 3 infusions of vedolizumab (induction phase) predicts responsiveness at 6 months of therapy.
Methods: Adult UC patients followed at a tertiary IBD center and treated with vedolizumab were included. Cumulative rates of clinical remission (CR, partial Mayo score ≤2 with a bleeding subscore 0) and steroid-free clinical remission (SFCR) were assessed at 3 and 6 months. Responses were calculated using nonresponder imputation. Mann-Whitney U-test was used for unpaired samples and Wilcoxon signed-rank test for paired samples to analyze for differences in CRP levels between patients in remission and in no remission at 6 months of continuous vedolizumab treatment.
Results: Fifty-seven UC patients (Table 1) were analyzed. Two thirds had prior anti-TNF treatment exposure and two thirds had pancolitis. All 57 patients completed 3 vedolizumab infusions by week 6 and 49 completed 5 infusions by week 22. Following 3 infusions, CR and SFCR were 37% (21/57) and 30% (17/57) and at 6 months the cumulative rates of CR and SFCR were 49% (28/57) and 44% (25/57) respectively (Table 1). Patients in remission at 6 months had significantly lower baseline median CRP levels compared to those not in remission (3 versus 12 respectively, p=0.005). Low CRP levels at baseline were not associated with steroid use. Only patients in remission at 6 months had a significant reduction of median CRP levels after 3 vedolizumab infusions as compared to median baseline levels (z=3.225, p=0.001, Figure 1). Nine out 36 patients who were non- responders after the induction phase achieved clinical remission at 6 months. Their (n=9) median CRP levels at baseline and after 3 infusions were significantly lower compared to the non-responders (n=27) (3 versus 13; z=2.028, exact p=0.043 and 2 versus 10, z=2.093, exact p=0.035, respectively).
Conclusions: Low baseline CRP levels and further reduction of the levels after the induction phase of vedolizumab treatment are associated with clinical remission at 6 months. A decrease in CRP following vedolizumab induction may be used to predict those patients who will be in clinical remission at 6 months.