A Danish study reports that switching from the originator drug infliximab (Remicade) to biosimilar CT-P13 (Inflectra/Remsima) does not appear to have had a negative effect on inflammatory arthritis disease activity in over 800 patients after 1 year of follow up. The study was published in the May 4, 2017 issue of Annals of the Rheumatic Diseases.
These results concur with findings presented at the Digestive Disease Week 2017 in Chicago last week.
The switch from Remicade to Inflectra was initiated by a Danish national guideline that all patients treated with infliximab should switch to the biosimilar for economic (not medical) reasons by May 2015. Patients and physicians had no say in the matter. In January 2017, the FDA issued a draft guidance about biosimilar interchangeability that recommended these kinds of switching studies be done to address safety and efficacy concerns around biosimilars.
The patients had rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (AxSpA) and were enrolled in the DANBIO rheumatic disease registry. Disease activities 3 months before and after the medication switch and changes over time were calculated.
A total of 802 patients (403 RA, 120 PsA, and 279 AxSpA; 51% women; median age 55) were switched from Remicade to Inflectra. The average treatment duration with the originator drug, prior to the switch to the biosimilar, was 6.8 years (range, 4.3 to 9.5 years). Follow up was 413 days, during which 16% stopped taking the biosimilar, mostly because of lack of effect or adverse events.
Bente Glintborg, MD, of the Rigshospitalet in Glostrup, and colleagues write that disease activities were similar 3 months before and following the switch from Remicade to the biosimilar infliximab. The absolute retention rates were 83.4% for the biosimilar and 86.8% for Remicade (P = .03), an absolute difference of 3.4%. Flare rate, defined as a change in 28 Joint Disease Activity Score greater than or equal to 1.2 (RA/PsA) or Ankylosing Spondylitis Disease Activity Score greater than or equal to 1.3, were also similar.
“To our knowledge, this is the first study of large-scale, nonmedical switching in routine care with prospective data collection,” the authors write. The availability of historic DANBIO disease registry data allowed the researchers to use the patients as their own controls with respect to fluctuations in disease activity before and after the switch, and to identify a historic infliximab cohort for comparison of retention rates. Patients whose previous infliximab treatment was longer than 5 years had a greater biosimilar retention rate. Retention rates for the biosimilar across diagnoses were comparable, though slightly lower for RA patients.
The study authors noted that the difference between 1-year retention rates for the biosimilar could be slightly lower than the originator drug because of a so-called “nocebo effect,” that is, negative expectations toward the drug or residual confounding.
The study was funded in part by a research grant from AbbVie.