Background: The biosimilar infliximab (IFX) can reduce healthcare costs when patients are switched from the reference to the biosimilar IFX; however this switch has raised concerns about potential immunogenicity. The objective of the SECURE study was to demonstrate that the IFX serum concentrations of the biosimilar IFX were non-inferior to the IFX concentrations of the reference 16 weeks after switch in subjects with rheumatoid arthritis, ulcerative colitis and Crohn's disease (CD) in stable remission for >30 weeks. This abstract presents the preliminary results of CD patients only.
Methods: In this prospective, open-label, interventional, non-inferiority, multicentre, phase IV trial, adult CD patients in clinical remission >30 weeks (Harvey Bradshaw Index; HBI ≤4) were switched from the reference IFX to the biosimilar IFX at stable doses. Patients were followed for 16 weeks after switch (2 infusions at 8 week interval). The primary endpoint was the serum IFX trough level concentration measured by a bridging enzyme-linked immunosorbent assay (ELISA) 16 weeks after switch (non-inferiority margin of 15%). Secondary endpoints included antibodies to IFX (ATI), clinical disease activity (HBI score), C-reactive protein (CRP), fecal calprotectin and quality of life (EQ-5D score) 16 weeks after switch compared to reference IFX.
Results: In total 61 CD patients were enrolled in 9 centers and 44 patients were included in the per protocol analysis (PP); 17 patients were excluded due to violation of eligibility criteria (4), not compliant with the study protocol (5), early termination of the study (3) and missing IFX serum samples (5). Mean age of the patients was 42±16 years (50% male) and mean duration on IFX treatment 4.9±3.8 years. The LS mean serum IFX concentration (90% CI) was 2.97 (2.78–3.18) for the reference IFX and 3.25 (3.04–3.48) 16 weeks after switch, with an IFX ratio of 109.6% (99.7%-120.6%) demonstrating non-inferiority of the biosimilar IFX to the reference IFX. One patient developed ATI's after 2 infusions. At the end of the study 38 (86%) patients were still in remission (HBI ≤4). The CRP, fecal calprotectin and EQ-5D were not significantly different for the biosimilar at week 16 compared to the reference IFX. In the enrolled population (61 patients) 2 SAEs (3.2%) were reported (both perianal abscess). The adverse event profile was not changed compared to the reference IFX.
Conclusions: This prospective, interventional study demonstrated that the IFX serum concentration of the biosimilar IFX was non-inferior to the IFX concentration of reference IFX 16 weeks after switching in patients with CD. Efficacy and tolerability were also similar.