Letter to the Editor: Missing mechanistic data and small inflammatory bowel disease cohorts: Key barriers in ustekinumab switching

This comment discusses the real-world study by Kritzinger et al , published in the recent issue of the World Journal of Gastroenterology , which reports preserved short-term clinical efficacy, stable biomarkers, and high treatment persistence after a mandatory non-medical switch from originator ustekinumab to a biosimilar in inflammatory bowel disease. While acknowledging the novelty and clinical relevance of these findings, the letter highlights two key limitations that constrain their applicab