Long-term effectiveness and safety of infliximab-biosimilar: A multicenter Phoenix retrospective cohort study.

Background: Infliximab (IFX) effectively treats patients with inflammatory bowel disease (IBD). IFX-biosimilar (IFX-BS) has the same amino acid sequence as that of the IFX originator, and its increasing use is expected to reduce national healthcare costs. Long-term efficacy and safety of IFX-BS in patients with Crohn's disease (CD) and ulcerative colitis (UC) have not been completely investigated.

Methods: We conducted a retrospective, multicenter observational study of patients with IBD who received IFX-BS treatment at three hospitals between October 2016 and April 2022. Clinical data were collected from electronic medical records and evaluated for achieving clinical remission (CR) using Crohn's disease activity index (CDAI) and partial Mayo (pMayo) score, persistency of long-term IFX-BS administration, and clinical response rate in the bio-naïve and bio-failure groups.

Results: A total of 117 patients with IBD (90 CD and 27 UC) were included. The study findings indicated that both bio-naïve and bio-failure groups of patients with UC showed similar effectiveness of IFX-BS. The treatment persistence rate in patients with CD was significantly higher in the bio-naïve (P = 0.042) and switch (P = 0.010) groups than in the bio-failure group. In the former two groups, the treatment persistence rate was high at two years after administration (more than 80%). In patients with UC, the findings indicated higher treatment persistence rate in the switch group than in the bio-naïve group. Univariable and multivariable analyses for treatment persistence rate showed that the albumin level at the initial IFX-BS administration and groups (bio-naïve, bio-failure and switch) were effective factors for patients with CD. Adverse events were reported in 18 patients (15.4%).

Conclusion: The present study demonstrates the long-term effectiveness and safety of IFX-BS. In addition to the favorable remission induction in the bio-naïve and bio-failure groups, we demonstrated remission maintenance and treatment persistence rates beyond two years. Albumin level and groups were associated with better treatment persistence in patients with CD.