Long-term efficacy and safety of biosimilar infliximab (CT-P13) after switching from originator infliximab: open-label extension of the NOR-SWITCH trial

J Intern Med. 2019 Jun;285(6):653-669. doi: 10.1111/joim.12880. Epub 2019 Apr 12.


Background and objectives: The 52-week, randomized, double-blind, noninferiority, government-funded NOR-SWITCH trial demonstrated that switching from infliximab originator to less expensive biosimilar CT-P13 was not inferior to continued treatment with infliximab originator. The NOR-SWITCH extension trial aimed to assess efficacy, safety and immunogenicity in patients on CT-P13 throughout the 78-week study period (maintenance group) versus patients switched to CT-P13 at week 52 (switch group). The primary outcome was disease worsening during follow-up based on disease-specific composite measures.

Methods: Patients were recruited from 24 Norwegian hospitals, 380 of 438 patients who completed the main study: 197 in the maintenance group and 183 in the switch group. In the full analysis set, 127 (33%) had Crohn's disease, 80 (21%) ulcerative colitis, 67 (18%) spondyloarthritis, 55 (15%) rheumatoid arthritis, 20 (5%) psoriatic arthritis and 31 (8%) chronic plaque psoriasis.

Results: Baseline characteristics were similar in the two groups at the time of switching (week 52). Disease worsening occurred in 32 (16.8%) patients in the maintenance group vs. 20 (11.6%) in the switch group (per-protocol set). Adjusted risk difference was 5.9% (95% CI -1.1 to 12.9). Frequency of adverse events, anti-drug antibodies, changes in generic disease variables and disease-specific composite measures were comparable between arms. The study was inadequately powered to detect noninferiority within individual diseases.

Conclusion: The NOR-SWITCH extension showed no difference in safety and efficacy between patients who maintained CT-P13 and patients who switched from originator infliximab to CT-P13, supporting that switching from originator infliximab to CT-P13 is safe and efficacious.

Trial registration: ClinicalTrials.gov NCT02148640.

Keywords: biosimilar; chronic inflammatory disease; drug costs; health economics; infliximab; switching.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antibodies, Monoclonal / adverse effects
  • Antibodies, Monoclonal / therapeutic use*
  • Arthritis / drug therapy*
  • Colitis, Ulcerative / drug therapy*
  • Double-Blind Method
  • Drug Substitution
  • Female
  • Humans
  • Infliximab / therapeutic use*
  • Male
  • Middle Aged
  • Norway
  • Psoriasis / drug therapy*
  • Time Factors
  • Treatment Outcome


  • Antibodies, Monoclonal
  • CT-P13
  • Infliximab

Associated data

  • ClinicalTrials.gov/NCT02148640
  • EudraCT/2014‐002056‐40