Quantitative Fluorescence Molecular Imaging of Ustekinumab-800CW to Elucidate the Drug Distribution Throughout Inflamed Tissue in Crohn's Disease and Psoriasis.

Crohn's Disease (CD) and psoriasis are chronic inflammatory diseases. Ustekinumab is a humanized monoclonal antibody. Ustekinumab is expensive and primary non-response is high in both CD and psoriasis. Currently, there are no predictors of response to ustekinumab and the actual mechanism of action has not yet been elucidated. To clarify the mechanism of action and gain a better understanding of the high primary non-response rates, the University Medical Center Groningen (UMCG) developed a tracer fluorescently labeling ustekinumab. This study aims to gain insight into ustekinumab distribution and concentrations in the gut. The current study aims to identify the ustekinumab target cells in the inflamed gut mucosa and skin using quantitative fluorescence molecular endoscopy (qFME). By gaining insight into local ustekinumab concentrations, drug distribution, and by discovering target cells, we expect to gain insight into the mechanism of action of ustekinumab.