Background: The infliximab biosimilar CT-P13 is EMA and FDA approved, based on data extrapolated from phase III studies in rheumatoid arthritis and ankylosing spondylitis patients. Anti-tumor necrosis factor (TNF) naive IBD patients frequently start CT-P13 in current daily practice but the switch from Remicade® to CT-P13 is less common due to limited data on long-term clinical outcomes. Therefore, we aimed to prospectively investigate long-term efficacy, safety, pharmacokinetic profile and immunogenicity following an elective switch from Remicade® to CT-P13 in IBD patients.
Methods: We performed a single-centre prospective observational cohort study. All Remicade®-treated IBD patients were actively switched to CT-P13 regardless of disease activity. Primary endpoint was change in disease activity scores at week 52 compared to week 0 as measured by Harvey-Bradshaw Index (HBI) for Crohn's disease (CD) and Simple Clinical Colitis Activity Index (SCCAI) for ulcerative colitis (UC) and IBD unclassified (IBD-U). C-reactive protein (CRP), fecal calprotectin (FCP), infliximab trough levels and antidrug antibodies to infliximab (ADA) were measured at week 0, 16 and 52. Adverse events and reasons for discontinuation were documented during follow-up.
Results: Eighty-three patients were included, 57 CD, 24 UC, 2 IBD-U (28 male, median age 36, range 18–79) and 68 patients completed 1-year follow-up. Median change in disease activity was 0 (HBI, range −9 to +15, n=49) for CD and 0 (SCCAI, range −4 to +4, n=19) for UC/IBD-U (Figure 1). FCP and CRP levels did not significantly change during follow-up. CT-P13 dosing was adjusted in 20/68 (29%) of the patients and the proportion of trough levels within the “therapeutic range” 3.0–7.0 ng/ml was 40% at baseline and 48% at week 52. In total 7 patients demonstrated detectable ADA during follow-up, 5/7 ADA titers were already detectable at baseline. Fifteen out of 83 patients (18%) discontinued CT-P13 during follow-up for reasons of clinical remission (n=3), loss of response (n=5) including 3/5 demonstrating detectable ADA, arthralgia (n=3), skin rash and itching (n=2) and migration to another hospital (n=2).
Conclusions: Eighty-two percent of the patients continued CT-P13 through 52 weeks after switching from Remicade®. Disease activity scores and inflammatory markers remained unchanged during follow-up and no CT-P13-related serious adverse events occurred. These 1-year data suggest that switching to CT-P13 in Remicade®-treated IBD patients is feasible.