Serum Ustekinumab Concentrations Are Associated With Improved Outcomes With the Magnetic Resonance Index of Activity for Crohn's Disease.

Higher ustekinumab concentrations were associated with improved radiologic (Simplified Magnetic Resonance Index of Activity for Crohn's Disease) and stringent biomarker (calprotectin) outcomes. The high concentration needed for these novel endpoints validates previous studies using the same assay.