Supplementary Material for: Case Report – Secukinumab (interleukin-17 inhibitor) and Ulcerative Colitis Flare: the double-edged sword

Secukinumab is an interleukin (IL)-17A inhibitor approved for psoriatic arthritis (PsA) and ankylosing spondylitis (AS). It´s use has been reported to be associated with inflammatory bowel disease (IBD) flare and new onset. We report a case of a 56-year-old woman with longstanding ulcerative colitis (UC) in remission, who developed a severe UC flare after initiating secukinumab for refractory PsA. She presented with extensive ulcerations, systemic inflammation needing hospitalization and change of treatment to risankizumab. This case highlights the emerging evidence of IL-17A blockade in IBD, potentially leading to adverse events, and adds to the growing body of evidence regarding the management of such complications with novel therapeutic approaches in severe cases. Physicians should be aware of this possibility when using IL-17A blockade in patients with pre-existing IBD..