New-onset inflammatory bowel diseases among IL-17 inhibitor-treated patients: results from the case–control MISSIL study

Objectives To describe new-onset IBD (new IBD) in patients treated with IL-17 inhibitors (IL-17i), to assess their incidence and to identify their risk factors in real life. Methods A French national registry (MISSIL) aimed to report all cases of new IBD in patients treated with IL-17i from January 2016 to December 2019. Using the estimated number of patients treated by IL-17 in France during the study period, the annual incidence rates of new IBD was reported in IL-17i-treated patients. A case–control study was performed with two controls per new IBD case matched by gender, age and underlying inflammatory disease. Results Thirty-one cases of new IBD under IL-17i were collected: 27 patients treated for spondyloarthritis and four patients for psoriasis. All were observed with secukinumab (SEK). The median time to onset of new IBD symptoms was 4.0 (1.5–7.5) months. SEK was discontinued in all patients. The evolution was favourable with complete resolution (17/31), improvement (7/31) or stabilization (5/31). Two patients died: one due to a massive myocardial infarction and one due to post-colectomy complications. The incidence of new IBD decreased from 0.69/100 patient-years [PY] (7/1010) in 2016 to 0.08/100 PY (6/7951) in 2019. No previous treatment with etanercept (odds ratio [OR] = 0.33, 95% CI: 0.14–0.80, P = 0.014) and low number of previous biologic therapies (OR = 0.67, 95% CI: 0.47, 0.94, P = 0.021) were significantly associated with new IBD. Conclusion The incidence of new IBD was low and decreased from 2016 to 2019. The outcome was favourable in 24 out of 31 patients, but two patients died.