Introduction

Vedolizumab (VDZ) is a monoclonal antibody approved for use in both Crohn’s Disease (CD) and Ulcerative Colitis (UC). Some patients treated with VDZ have suboptimal disease response to induction and 8-weekly maintenance dosing. Dose intensification (DI) by shortening the dosing interval is a strategy used to improve response to treatment. This study aims to identify factors associated with DI in an Asian cohort of IBD patients.

Aims & Methods

This was a retrospective cohort study performed in a single tertiary center in Singapore. Patients who received VDZ between Sept 2016 to Sept 2022 were identified from a prospectively maintained registry. Patient demographics, disease phenotype, treatment history and biochemical parameters were retrieved. Factors predictive of requiring DI were analysed. Statistical analysis was performed using SPSS v23.0.

Results

A total of 69 IBD patients who received VDZ were identified. Mean age was 57.1 years (SD=20.1). Males made up 63.1% of the cohort, with 3 patients (4.6%) being active smokers. Thirty-nine patients (60.0%) had prior exposure to immunomodulators, 32 patients (49.2%) had prior anti-tumour necrosis factor-alpha inhibitor exposure, 5 patients (7.7%) had prior ustekinumab exposure. None of the patients had prior exposure to small molecules.
A total of 4 patients (6.2%) had prior exposure to 2 biologic agents, 30 patients (45.2%) had prior exposure to 1 biologic agent, and 31 patients (47.7%) were biologic-naïve. Disease duration prior to VDZ use was 8.4 years (SD=8.0). VDZ treatment duration was 24.4 months (SD=19.2).
A total of 25 patients (10 CD, 15 UC) underwent DI. Time from induction to DI was 384.4 days (SD=301.2). Gender, active smoking status, age of diagnosis, previous treatment or biologic exposure, higher pre-induction C-reactive protein and stool calprotectin did not predict for need for DI. (Figure 1)
Four patients achieved clinical remission post induction but subsequently required DI. Fourteen patients underwent DI to Q6W dosing and 11 patients received Q4W dosing. Patient demographics are shown in Figure 2a.
Outcomes of DI at 52-weeks post DI is shown in Figure 2b. Eight patients (32.0%) achieved treatment endpoints of corticosteroid-free remission (n=2), biochemical remission (n=2) and endoscopic remission (n=4). Mean duration on VDZ with DI in CD was 9.9months (SD=9.1), and 35.9months (SD=19.9) in UC.
Ten patients were switched to another biologic. Five (2 UC, 3 CD) patients required surgery despite DI. One patient had recurrent Clostridium difficile infections while on VDZ. There were no other complications or hospitalizations associated with DI.

Conclusion

This is the first VDZ DI study in Asia. One third of patients who receive VDZ required DI, of which a third achieved remission by week 52. Some Asian patients with IBD may require DI to achieve remission.