In Crohn Disease, BMI Does Not Affect Ustekinumab Efficacy

A patient’s body mass index (BMI) does not affect the efficacy of ustekinumab in Crohn disease (CD), according to results of a new study.

The finding stems from the IM-UNITI study, a post hoc analysis of data from a 44-week maintenance trial of ustekinumab in patients with CD. Based on the patients’ BMI at study entry, the researchers stratified participants into underweight (<18.5 kg/m²), normal weight (18.5 to 25 kg/m²), overweight (25 to <30 kg/m²), and obese (≥30 kg/m²) subgroups.

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Clinical remission was defined as CD activity index less than 150 and corticosteroid-free clinical remission at week 44. Among 254 patients treated with ustekinumab, the rates of clinical remission at week 44 were 67.9% for those with underweight, 51.3% for those with normal weight, 45.1% for those with overweight, and 55.3% for those with obesity. After adjusting for covariates, BMI was not a significant predictor of clinical remission. 

The researchers did find a significantly lower ustekinumab drug level at week 44 among participants with obesity compared with other participants. Patients with obesity had a median ustekinumab level of 2.98 mcg/mL. Meanwhile, the median drug level was 4.84 mcg/mL among patients with overweight and 4.43 mcg/mL among patients with underweight or normal weight. 

“Although BMI impacts ustekinumab drug levels, there was no impact of BMI on clinical efficacy,” the researchers concluded. “Further studies of the pharmacodynamic effects of ustekinumab in patients with high BMI are needed.”

—Jolynn Tumolo

Reference:

Wong ECL, Marshall JK, Reinisch W, Narula N. Body mass index does not impact clinical efficacy of ustekinumab in Crohn’s disease: a post hoc analysis of the IM-UNITI trial. Inflamm Bowel Dis. Published online August 19, 2020. doi:10.1093/ibd/izaa214