Effectiveness of an Infliximab Biosimilar vs. Originator in Inflammatory Bowel Diseases: A Noninferiority Nationwide Study From the epi-IIRN.

Goals: Definitively prove noninferiority of biosimilar infliximab to originator.

Background: The advent of biosimilar agents has made biological medications for inflammatory bowel diseases (IBD) more affordable and widely available. We conducted a noninferiority assessment of the effectiveness of the infliximab biosimilar agent CT-P13 versus the original for treatment of IBD in a nationwide analysis.

Study: We used the Epidemiology Group of the Israeli Inflammatory Bowel Disease Research Nucleus Cohort (epi-IIRN), including data on patients with IBD from all Health Maintenance Organizations (HMO) and conducted a noninferiority analysis of infliximab originator and biosimilar CT-P13 based on time from induction of treatment until failure. Treatment failure was defined as steroid dependency, need for IBD-related surgery, or treatment change to an alternative biological. The groups were matched using a propensity score of 0.15 caliper based on sex, ethnicity, district, socio-economic status, age at diagnosis, disease activity, time until biological treatment, prior biological treatments, surgeries, and hospitalizations.

Results: We compared 564 patients treated with infliximab originator matched to 564 treated with CT-P13. The results proved noninferiority in all parameters, with a margin of d=10% or smaller over 5 years (P<0.05). In time to failure, noninferiority was demonstrated with a d=1% (P=0.0004). Noninferiority was also demonstrated in time to steroid dependency (d=5%, P=0.005), surgery (d=1%, P=0.0006), and transfer to alternative biological drug (d=1%, P<0.001). Subanalyses for Crohn's disease and ulcerative colitis separately yielded similar results.

Conclusions: This study demonstrated noninferiority of infliximab biosimilar CT-P13 in comparison to the original in long-term management of IBD.