Objective: Real-life data regarding Inflammatory Bowel Disease (IBD) evolution after switch from intravenous (IV-IFX) to subcutaneous infliximab (SC-IFX) is necessary. The aim of this prospective multicenter cohort study was to describe the persistence, effectiveness and tolerance of SC-IFX after switch from IV-IFX.

Methods: IBD patients in steroid-free clinical remission for at least 6 months on IV-IFX, were enrolled in a prospective national French cohort when they switched to SC-IFX. Patients were assessed at inclusion and at weeks (W) 12, 24 and 48. Primary endpoint was the persistence of SC-IFX at W48. Secondary endpoints comprised steroid-free clinical remission at W48, IV-IFX switch-back rate, and evolution of infliximab levels during the study period.

Results: Among the 426 patients included (72.4% with Crohn's disease (CD), 27.5% with ulcerative colitis (UC); 45.1% females; median age 37 [29-50] years; median disease duration of 12 years in CD, 13 years in UC), 56% were on IV-IFX standard dosing (5mg/kg 8-weekly) and 16% received combination therapy with an immunomodulator drug at baseline. At W48, SC-IFX persistence was 95.4% (95%CI, 93.3-97.5) and 86.9% of patients were on steroid-free clinical remission. Mean infliximab levels were 8.0μg/mL at inclusion and 18.0 μg/mL at W48 (p<0.0001). Among the 19 (4.5%) patients who stopped SC-IFX, 6 (1.4%) switched back to IV-IFX. There were 222 adverse events reported in 42.4% of patients, 12 led to treatment discontinuation, including six (1.4%) severe adverse events.

Conclusions: In this large multicenter prospective cohort, persistence at one year of SC-IFX was more than 95% of IBD patients switched in remission from IV-IFX, confirming excellent effectiveness and tolerance of SC-IFX.