Body Mass Index Does Not Impact Clinical Efficacy of Ustekinumab in Crohn’s Disease: A Post Hoc Analysis of the IM-UNITI Trial

Abstract

Abstract Background This post hoc analysis aimed to evaluate the impact of BMI on the efficacy of ustekinumab in the IM-UNITI study. Methods The relationship between body mass index (BMI) and efficacy of ustekinumab was evaluated using data from a 44-week maintenance study of ustekinumab in Crohn’s disease (IM-UNITI, NCT01369355, YODA #2019–4105). The primary endpoints of interest were clinical remission (CR), defined as Crohn’s disease activity index <150 and corticosteroid-free CR at week 44. Patients were stratified into the following subgroups according to their BMI at study entry: underweight <18.5 kg/m2, normal 18.5 to 25 kg/m2, overweight 25 to <30 kg/m2, and obese ≥30 kg/m2. The χ 2 test of linear trend was conducted for comparisons of frequencies between the 3 cohorts. Multivariate regression analyses evaluated possible association between BMI and efficacy outcomes of CR and corticosteroid-free CR, with adjustment for variables found significant on univariate analyses. Results are presented as odds ratios with 95% confidence intervals. Data were analyzed using Stata/IC 15. Results A total of 254 patients treated with ustekinumab were included in this analysis. At week 44 of IM-UNITI, rates of CR did not differ among those whose BMI was underweight (67.9%%; 19 of 28 patients), normal (51.3%; 60 of 117), overweight (45.1%; 32 of 71), or obese (55.3%; 21 of 38; P = 0.89). Multivariate logistic analysis did not find BMI to be a significant predictor of CR when adjusted for covariates. Ustekinumab drug level at week 44 was significantly lower in obese patients (median level 2.98 mcg/mL; interquartile range [IQR], 2.86) compared with patients who were overweight (4.84 mcg/mL; IQR, 3.51; P = 0.021) or had underweight or normal BMI (4.43 mcg/m;, IQR, 2.82; P = 0.014). Conclusions Although BMI impacts ustekinumab drug levels, there was no impact of BMI on clinical efficacy. Further studies of the pharmacodynamic effects of ustekinumab in patients with high BMI are needed.