Descriptive: A 24-month multicentre, observational, prospective cohort study. Population: IBD Patients under stable clinical and biological remission Study treatments: Patients who will be proposed to switch, or who have just switched, from the intravenous originator Remicade® or one of its biosimilars to the subcutaneous infliximab Remsima®SC as part of routine care. All consecutive patients in IBD centers participating in the study will be proposed to participate in the study during their regular outpatients' visits.

Objectives:The primary objective of PEREM study is to determine the rate of persistence of subcutaneous infliximab at 48 weeks after switching from IV infliximab to subcutaneous infliximab Remsima®SC.

Number of patients: 400 patients in approximatively 40 sites in France Recrutment period: The trial duration for each patient will be 2 years Main Endpoint:The primary endpoint is to assess the rate of persistence of subcutaneous infliximab at month 12 after switching from IV infliximab to SC infliximab Remsima®SC.

Secondary Endpoint:

• Percentage of patients on steroid free clinical remission at week 96 after switch. Steroid-free Clinical Remission (CR) is defined as a Harvey Bradshaw Index (HBI) score≤4 CD patients and a Partial Mayo Score (PMS) ≤2 with each sub-score of 1 or less for UC. When HBI scoring will be infeasible (stoma, pouch), evaluation of clinical remission will be estimated by stoma emptying count and/or by the physician global assessment (Sturm 2019) Patients having discontinued subcutaneous infliximab Remsima®SC therapy whatever the reason during the 24 months of follow-up as well as patients referred to disease-related surgery and patients lost to follow-up before month 24 will be considered as failure to subcutaneous infliximab Remsima®SC therapy (intention to treat analysis) and will be classified in the group of patients having failed to maintain steroid free clinical remission under infliximab Remsima®SC during the whole study period.
• Percentage of patient Reported Outcomes PRO2 rates at inclusion, months 3, 6, 12 and 24
• Percentage of biological remission rates (FC <250 μg/g, CRP <5 mg/L) at inclusion, month 3, 6, 12 and 24.
• Percentage of clinical relapse free rates at inclusion, month 3, 6, 12 and 24
• Percentage of loss of response rates at inclusion, month 3, 6, 12 and 24
• Percentage of clinical response and remission at inclusion, month 3, 6, 12 and 24
• Mean change from baseline in HBI or PMS, and mean change from baseline in CRP and fecal calprotectin
• Proportion of patients with positive antibodies (IFX, ANA) comparing therapy with intravenous or one of its biosimilars original and subcutaneous infliximab Remsima®SC
• Measure adherence to subcutaneous infliximab Remsima® switch based on pharmacy data during the follow-up with Medication Possession Ratio (MPR ).
• Twelve-month cumulative surgery rates
• Hospitalization rate at month 24
• Cumulative infection rate at month 24
• Cumulative SC reactions at month 24
• Discontinuation of subcutaneous infliximab therapy cumulative rates at month 24
• Incidence of specific anti-drug antibodies detected during the study

Inclusion Criteria:

• • Male or female subjects who are more than 18 years of age, on the day of signing informed consent.

  • Patient affiliated to the health insurance system.
  • Documented diagnosis of CD or UC established based on standard clinical, endoscopic, and histological criteria.
  • CD or UC remission defined per clinical assessment as a Harvey Bradshaw Index (HBI) score ≤4 for CD patients and a Partial Mayo Score (PMS) ≤2 with each sub-score of 1 or less for UC and/or according to ECCO classification within previous 6 months.
  • Currently treated with IV infliximab: originator or biosimilars.
  • Patients agreeing to switch from IV to SC formulation or who have already switched since maximum 3 months.
  • Receiving or not the concomitant following drugs (but must remain on stable dose for 12 weeks):

• Oral 5-aminosalicylates (5ASA) compounds or rectal formulations of 5ASA provided the dose to be stable at least 4 weeks before switching.

• Azathioprine, 6-MP or methotrexate provided the dose has been stable for 4 weeks prior to inclusion (dose must remain stable for 10 weeks after switching).

  • Each patient is required to provide written informed consent to be included in the study.

Exclusion Criteria:

• Current use of vedolizumab or ustekinumab
• Current use of JAK inhibitors or S1P modulators
• Current use of steroids or within the last three months for IBD
• Treatment with any investigational agent in the past 30 days or five half-lives prior to the inclusion visit
• Current CD abscess
• Active clinically significant infection or HIV, Hep B, Hep C, untreated tuberculosis
• Female subjects with pregnancy or breastfeeding

Age ≥ 18 ans, CD patients (HBI ≤4) or UC patients (PMS ≤2) with established diagnosis > 6 months treated with Infliximab IV, agreeing to switch from IV to SC formulation or who have just switched to subcutaneous infliximab Remsima®SC as part of routine care