Pooled data from 5 randomized phase 3 trials of patients with moderately to severely active ulcerative colitis (UC) support the sensitivity and specificity of fecal calprotectin (FC) in predicting endoscopic improvement across race, ethnicity, and sex, according to a research team led by Christina Ha, MD, in a e-poster presentation at Digestive Disease Week 2022 in San Diego, California.

However, the authors noted, “these results demonstrate heterogeneity in related numeric cutoffs. Differential influences of disease biology versus social determinants of health upon FC interpretation remain unclear.”

FC is widely used as a key biomarker in the clinical management of patients with inflammatory bowel disease (IBD). The objective of this study was to determine how FC performed in predicting endoscopic improvement, measured by Mayo endoscopic score (MES), among 2000 patients aged 18 to 80 years old, according to ethnic, racial, and sex subgroups.

The researchers analyzed pooled data from the induction and maintenance populations of the phase 3 HIBISCUS I & II, HICKORY, LAUREL and GARDENIA trials of etrolizumab in UC. The participants included had at least one available MES and FC assessed by a central laboratory central laboratory (BÜHLMANN fCAL® ELISA) measured during the same week.

A total of 1779 patients who completed the induction trials and 352 who finished the maintenance phase fulfilled criteria for inclusion in the analysis. The majority were non-Hispanic/non-Latino, White, and male.

“In univariate analyses at the end of induction, the sensitivity and specificity of FC to predict MES ≤ 1 were consistent among all groups, with a minimum of 70% sensitivity and specificity observed,” the authors wrote. “Following maintenance, these data were variable, though the number of patients was comparatively small at this timepoint. Induction and maintenance FC cut-off values were similar for the entire cohort, but these results were mainly driven by Caucasians. FC cut-offs were generally mixed when comparing subgroups during induction and maintenance, though Hispanics consistently demonstrated higher cutoff values when compared with the entire cohort.”

The investigators concluded, “These data underscore the importance of considering a precision approach to the use of FC in the care of patients with UC, as well as the need for greater racial and ethnic diversity in clinical trials to support an understanding of inflammatory bowel disease in underrepresented patient groups.”

—Rebecca Mashaw

Ha C, Oh Y, Reiss W, Yang W, Yoo B, Reilly NR. Race, ethnicity, and sex-related heterogeneity in fecal calprotectin prediction of endoscopic activity in ulcerative colitis. Presented at: Digestive Disease Week; May 21, 2022. San Diego, CA.