Could NOR-SWITCH EXTENSION Data Allay Concerns About Switching in IBD?

The NOR-SWITCH trial—a 52-week, double-blind, noninferiority trial that has become the basis on which the case for switching patients to biosimilars has been made—demonstrated that switching from reference infliximab to biosimilar infliximab (CT-P13) was noninferior to continued treatment with the reference product in terms of efficacy, safety, and immunogenicity.

However, the study was not powered to demonstrate noninferiority of the biosimilar in the individual disease states, including Crohn disease (CD), ulcerative colitis (UC), rheumatoid arthritis, psoriatic arthritis, and psoriasis. In recent months, those who are skeptical about switching patients to biosimilars have highlighted this fact, and some clinicians have asked whether the extrapolation of indications is reasonable.

Last week, at the European Crohn’s and Colitis Organisation’s 13th annual congress in Vienna, Austria, researchers presented data from the NOR-SWITCH EXTENSION trial—a 26-week open label extension trial—concerning the inflammatory bowel disease (IBD) subgroup.

The extension assessed the safety of uninterrupted treatment with biosimilar inflixmab through week 78 compared with switching from the reference product to the biosimilar at week 52. The primary endpoint of the extension was overall disease worsening during follow-up.

In total, 380 of 438 patients who completed the main trial entered the extension, and overall disease worsening occurred in 16.8% in the CT-P13 maintenance group and 11.6% in the switch group. The 95% confidence interval (CI) of the adjusted difference was within the pre-specified 15% noninferiority margin. The incidence of adverse events, presence of anti-drug antibodies, and patient-reported outcome measures were also comparable between the 2 groups.

Disease worsening occurred in 20.6% and 12.1% of the maintenance group and the switch group, respectively, among patients with CD, and 15.4% and 2.9% in the maintenance group and the switch group, respectively, among patients with UC. The researchers report that these findings were also within the pre-specified noninferiority margin.

Changes from baseline to the study’s end in both CD and UC showed similarity between the maintenance and switch arms with respect to the Harvey Bradshaw Index, Partial Mayo score, C-reactive protein, and fecal calprotectin.

The authors concluded that the open-label extension did not show any difference between patients who remained on CT-P13 versus those who switched from the reference product to the biosimilar, and that the exploratory subgroup analyses of patients with CD and UC showed similarity between the groups in terms of efficacy, safety, and immunogenicity.

Reference

Jørgensen KK, Goll GL, Sexton J, et al. Long-term efficacy and safety of biosimilar infliximab (CT-P13) after switching from originator infliximab: explorative subgroup analyses in IBD from the NOR-SWITCH EXTENSION trial. Presented at the 13th Congress of the European Crohn’s and Colitis Organisation, February 14 to 17, 2018; Vienna, Austria. Abstract P483. https://www.ecco-ibd.eu/publications/congress-abstract-s/abstracts-2018/item/p483-long-term-efficacy-and-safety-of-biosimilar-infliximab-ct-p13-after-switching-from-originator-infliximab-explorative-subgroup-analyses-in-ibd-from-the-nor-switch-extension-trial.html