Effect of obesity on vedolizumab response in inflammatory bowel disease

BACKGROUND: Vedolizumab is used in inflammatory bowel disease (IBD), administered as a non-weight-based fixed dose. A higher body mass index (BMI) is associated with lower serum vedolizumab levels, but it is unclear whether it is associated with an unfavorable response to vedolizumab. We examined the relationship between BMI and the need for dose escalation, and the overall response to vedolizumab in IBD patients. METHODS: This was a single-center, retrospective study of IBD patients who received vedolizumab between 1(st) July 2014 and 1(st) September 2020. The primary outcome was need for vedolizumab dose escalation or discontinuation. Secondary outcomes were steroid-free clinical remission (SFCR), endoscopic remission, and normal serum C-reactive protein (CRP). Outcomes were compared between patients with BMI <30 kg/m(2) (non-obese) or ≥30 kg/m(>2) (obese). RESULTS: 190 patients were included, with a median follow-up time of 21 months. Median age was 37 years, 50.5% were male, and median BMI was 24.8 kg/m(2) (75.3% of patients had BMI <30 kg/m(2)). Vedolizumab was dose-escalated in 48.9% of the obese group vs. 42% of the non-obese group (P=0.4). Vedolizumab was discontinued in 31.9% of the obese group vs. 53.2% of the non-obese group (P=0.01). The rate of CRP normalization was significantly lower in the obese group (46.2% vs. 66%, P=0.03). SFCR and endoscopic remission rates were not significantly different between the groups. CONCLUSIONS: Obesity was not associated with higher rates of vedolizumab dose escalation. However, it was associated with lower rates of vedolizumab discontinuation and CRP normalization, but not SFCR or endoscopic remission.