EFFICACY, SAFETY AND PHARMACOKINETIC DATA OF SWITCHING FROM INTRAVENOUS TO SUBCUTANEOUS INFLIXIMAB IN INACTIVE INFLAMMATORY BOWEL DISEASE PATIENTS. REAL-LIFE EVIDENCE FROM ENEIDA REGISTRY.

Background
Switching from originator to biosimilar infliximab (IFX) is effective and safe. However, data on multiple switching are scarce. The Edinburgh IBD unit has undertaken three switch programmes: (1) Remicade to CT-P13 (2016), (2) CT-P13 to SB2 (2020), and (3) SB2 to CT-P13 (2021). The primary endpoint of this study was to assess CT-P13 persistence following switch from SB2. Secondary endpoints included persistence stratified by the number of biosimilar switches (single, double and triple), effectiveness and safety.
Methods
We performed a prospective, observational, cohort study. All adult IBD patients on IFX biosimilar SB2 underwent an elective switch to CT-P13. Patients were reviewed in a virtual biologic clinic with protocol driven collection of clinical disease activity, CRP, faecal calprotectin (FC), IFX trough / antibody levels, and drug survival.
Results
297 patients (CD n=196 [66%], UC/IBDU n=101, [34%]) were switched. This was the third, second and first IFX switch for 67 /297 (22.5%), 138 /297 (46.5%) and 92 /297 (31%) of the cohort respectively. Patients who underwent multiple IFX biosimilar switches had longer disease duration (p=0.0001) and IFX duration (p=0.0001) and were less often on combination therapy with an immunomodulator (p=0.0001).
90.6% of patients remained on IFX during a median follow-up of 7.5 months [6.8-8.1] (figure 1). The number of switches was not independently associated with IFX persistence after adjusting for confounders (table 1). Clinical (p=0.77), biochemical (CRP ≤5mg/mL; p=0.75) and faecal biomarker (FC<250µg/g; p=0.63) remission were comparable at baseline, week 12 and week 24.
Conclusion
Multiple successive switches from IFX originator to biosimilars are effective and safe in patients with IBD, irrespective of the number of IFX switches.

Recently, a subcutaneous formulation of biosimilar infliximab (CT-P13) (SC-IFX) has been approved for inflammatory bowel disease (IBD). Aim: to evaluate efficacy, safety, pharmacokinetics and patient experience following a switching to SC-IFX in patients who are in clinical remission on IV-IFX maintenance treatment. Methods: Multicentre, descriptive, and observational study including Crohn’s disease (CD) and ulcerative colitis (UC) patients who were going to be changed from IV-IFX to SC-IFX on the ENEIDA registry (a large, prospectively maintained database of the Spanish Working Group in IBD–GETECCU). All patients were on clinical and biological remission at least 24 weeks before changing. Demographic and disease data, clinical activity (Harvey-Bradshaw index for CD and mayo index for UC), analytical data (C reactive protein (CRP) and fecal calprotectin (FC), as well as trough levels were collected at baseline, at 12 and 24 weeks. Results:
One hundred and fifty-five patients were included: 54 UC (35%) and 91 (65%) CD; 44% women and 56% men; age 45.5 years (32-55). IV-IFX was mainly administered due to active disease (72%) and perianal disease (7%) and during 32 months [range 14-56]. Pre-switch, 78 (50.3%) were on 8-weekly dosing of IV-IFX, 77 (49.7%) were with intensification dose and the half (50.3%) were on concomitant immunomodulatory therapy. SC-IFX was mainly switching by COVID-19 pandemic (60%), to increase through levels (15%) or patient request (25%). The majority of patients (140, 90%) remained with standard dose, 8 (5%) required dose intensification (120 mg weekly in 4 and 240 mg every 2 weeks in 4) and 7 (4.5%) had successful de-escalation (120 mg every 3 weeks in 4 and 120 mg every 4 weeks in 3). Clinical indices, CRP levels and FC remained unchanged (Figure). Median SC-IFX levels significantly increased from baseline of 4.5 μg/dl [range 2.6-9.2] to 14 μg/dl [range 9.5-16.2] at 12 weeks and 13.2 μg/dl [range 10.4-19.7] at 24 weeks No factors (immunossupresor, body mass index, disease location) were associated with the increase of IFX trough levels. During 24 weeks of follow-up, 16 of the 78 (20.5%) patients stopped immunosuppressant treatment. The adverse events were recorded in 9 patients (5.8%), 4 (2.6%) were hospitalized and 4 (2.6%) had surgery (one of them for perianal disease). Nine patients (5.8%) stopped SC-IFX (1 primary failure, 2 loss of response, 4 adverse events, 1 voluntarily, and 1 surgery). Conclusion: The switch from IV to SC IFX maintains clinical remission safely in IBD, offers higher drug levels and a good patient acceptance. However, the significance of higher drug levels with SC-IFX requires further exploration.