Risankizumab for Refractory Perianal Fistulizing Crohn's Disease

Crohn's disease is an inflammatory bowel disease characterized by relapses and remissions, causing lesions throughout the digestive tract and accompanied by diarrhea, abdominal pain, and nutritional disorders. In Japan particularly, the incidence of anal lesions is high, with approximately half of patients developing fistulas or abscesses, significantly impairing quality of life (QOL). For perianal fistulizing Crohn's disease (PFCD), combined treatment with surgical intervention (e.g., seton placement) and medical therapy centered on anti-TNF agents is standard. However, challenges remain regarding efficacy rates and evaluation criteria. Novel therapies such as stem cell therapy, JAK inhibitors, and IL-23 inhibitors are gaining attention. This study using risankizumab aims to be the first in Japan to comprehensively evaluate the therapeutic efficacy of PFCD using both clinical and MRI assessments, thereby contributing to future treatment standardization and guideline development.