TBA (23W163)

Analyses Of Peripheral Eosinophil Levels As A Predictor Of Response To Treatment In Patients Receiving Vedolizumab For Inflammatory Bowel Disease

Author(s)

Shane Elwood (1), Laura Neilan (1), Danny Cheriyan (1,2), Aoibhlinn O Toole (1,2), Stephen E Patchett (1,2), Karen Boland (1,2)

Department(s)/Institutions

1. Department of Gastroenterology, Beaumont Hospital, Dublin 9 2. School of Medicine, Royal College of Surgeons in Ireland

Introduction

Vedolizumab is a gut-selective integrin antagonist used for the induction and maintenance of remission in patients with moderate to severe inflammatory bowel disease (IBD). Eosinophils are increasingly implicated in chronic intestinal inflammation. We noted an association between raised serum eosinophil levels and use of vedolizumab therapy.

Aims/Background

To examine a rise in peripheral eosinophil count above the upper limit of normal as a potential predictor of response to treatment in IBD patients receiving vedolizumab.

Method

We retrospectively reviewed the clinical records and blood results of 62 IBD patients on vedolizumab attending Beaumont Hospital. Serum eosinophil levels before and after induction of therapy were documented, where the post treatment eosinophil count was taken as the peak level within the first 24 months of treatment. Chi-Square Test of Independence was used with p-value <0.05 donating statistical significance.

Results

Preliminary data includes 62 patients. 66.1% (n=41) had ulcerative colitis, 30.6% (n=19) Crohn’s disease, 3.2% (n=2) IBDU. 86.4% (n=53) had mucosal response to vedolizumab. Of those who responded to treatment, 40%% (n=21) had an eosinophil count above 0.4x109 /L (0.42-1.1x109 /L) post-induction, p=0.03. Onset of the peak in eosinophil level was variable, ranging between 1- and 16-months after delivery of first dose. The average change in eosinophil level was seen to be higher amongst responders (0.18745) when compared to non-responders (0.09375).

Conclusions

A high eosinophil count following initiation of treatment may be an early predicter of response in patients receiving vedolizumab therapy for IBD. Serum eosinophilia has been reported in natalizumab-treated patients with MS. We are expanding analysis to study this pattern and its potential use as a biomarker of response to anti-integrin therapy.