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

BACKGROUND AND OBJECTIVES: The 52-week, randomized, double blind, non-inferiority, 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) vs patients switched to CT-P13 at week 52 (switch group).

PRIMARY OUTCOME: 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, 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 non-inferiority 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. This article is protected by copyright. All rights reserved.