TBA (22W173)

Correlation between Vedolizumab Levels and Clinical, Endoscopic and Histological Remission in Patients with Inflammatory Bowel Disease

Author(s)

S. Samodee, V. Madhu, S. Bennett, A. Keogh, E. Slattery

Department(s)/Institutions

Department of Gastroenterology, University Hospital Galway

Introduction

Data from clinical trials and real-world cohorts suggest an exposure-efficacy relationship of vedolizumab in patients with inflammatory bowel disease (IBD). Therapeutic drug monitoring is a useful tool to optimise management of IBD but its role in patients on vedolizumab is less clear compared to anti-TNF drugs such as infliximab.

Aims/Background

This study aimed to assess objective disease markers and vedolizumab drug levels to determine whether an exposure-response relationship exists.

Method

A database with 60 eligible IBD patients who were maintained on vedolizumab since 2014 was used. The most recent vedolizumab level (which did not form part of the clinical management of these patients), clinical, endoscopic and histological findings were obtained using local electronic systems. SPSS software was used to perform data analysis. Dose optimisation was not driven by drug levels; only clinical symptoms/response.

Results

Of 60 patients, 32(53.3%) were female and 28(46.7%) were male. Median age was 47. 44(73.3%) of patients had UC and 15(25%) had CD. Vedolizumab levels ranged from 2.8 to 48.7μg/ml. 26.7% of patients were on escalated vedolizumab dosing; 7(11.7%) on 6-weekly dosing and 9(15%) on 4-weekly dosing with 60% of these patients having achieved clinical remission and 63.6%(n=11) with inactive/mild active inflammation on histology. There was moderate correlation found between dosing intervals and vedolizumab levels(r=.38) and vedolizumab dosing and clinical symptoms(r=.44). There was no correlation between vedolizumab levels and clinical symptoms (r=.21) or between vedolizumab levels and histologic findings (r=.08) suggesting that drug levels do not correlate with clinical or histological outcomes. These findings were similar for endoscopic outcomes (r=-.19). While most patients on vedolizumab were in clinical remission, 8.3% (n=48) patients had mild symptoms,2% had moderate symptoms and 2% had a severe flare. These patients were all on escalated dosing regimens of vedolizumab; 3(50%) on 6-weekly and 3(50%) on 4-weekly dosing. 5 of these 6 patients had trough levels ranging from 4.3 to 36.1μg/ml.

Conclusions

This study suggests that there is no correlation between vedolizumab levels and clinical, endoscopic and histological outcomes in IBD patients. However, dosing intervals were found to be positively correlated with both vedolizumab levels and clinical symptoms. Further work on the role of drug monitoring in vedolizumab is required.