No Negative Effect on Disease Activity Seen in Switching Patients to Biosimilar Infliximab From Originator Drug

Patients who switched from originator infliximab to biosimilar infliximab showed no negative effect on disease, according to a recent study published in the Annals of the Rheumatic Diseases.

“To our knowledge, this is the first study of a large-scale, non-medical switching in routine care with prospective data collection,” Bente Glintborg, MD, from the Center for Rheumatology and Spine Diseases and Center of Head and Orthopedics at Rigshospitalet in Glostrup, Denmark, and colleagues wrote in their study.

“Similar results of largely unchanged disease activity after the switch have been reported in smaller observational studies of <40 patients with inflammatory arthritis and inflammatory bowel disease, whereas few have reported negative outcomes.”

Dr Glintborg and colleagues used observational data from 403 patients with rheumatoid arthritis (RA), 120 patients with psoriatic arthritis (PsA), and 279 patients with axial spondyloarthritis (AxSpA) from the Danish DANBIO registry to examine disease activity after a nonmedical, nationwide switch from originator infliximab (INX, Remicade) to biosimilar infliximab (CT-P13, Remsima).

The researchers measured disease activity 3 months before and after the switch, using change in 28-Joint Disease Activity Score in patients with RA and PsA, as well as the Ankylosing Spondylitis Disease Activity Score for patients with AxSpA.

Patients were an average age of 55 years (interquartile range, 44-66 years), followed for average of 413 days (interquartile range, 339-442 days) after the switch to CT-P13, and had prior INX treatment for an average duration of 6.8 years (range, 4.3-9.5 years). Dr Glintborg and colleagues measured retention rates using a historic cohort of INX patients: a flare was recorded if the 28-Joint Disease Activity Score was ≥1.2 points, or if the Ankylosing Spondylitis Disease Activity Score was ≥1.3 points.

The researchers found a similar disease duration the 3 months before and after the switch to CT-P13, with patients who switched to CT-P13 having a crude 1-year retention rate of 84.1% (95% CI, 81.3%-86.5%) compared with 86.2% in the historic INX cohort (95% CI, 84.0%-88.0%; P =.22). After performing a Cox proportional hazards regression analysis, Dr Glintborg and colleagues found the CT-P14 group had an adjusted retention rate of 83.4% (95% CI, 80.8%-86.2%) compared with 86.8% (95% CI, 84.8%-88.8%; P =.03) in the historic INX group.

Overall, 132 patients withdrew from the study; of these, 54% withdrew because of the medication having no effect (n=71), and 28% withdrew because of adverse events (n=37). The researchers noted patients taking INX for <5 years tended to have better retention when switching to CT-P13.

Summary & Clinical Applicability

“This study of a large cohort of real-life patients contributes important knowledge of postmarketing effectiveness of non-medical switching,” Dr Glintborg and colleagues wrote. “The availability of historic DANBIO data enabled us to use the patients as their own controls regarding fluctuations in disease activity before and after the switch, and to identify a historic INX cohort for comparison of retention rates.”

Limitations & Disclosures

The researchers noted that the observational nature of the study led to incomplete data.

Glintborg reports competing interests from AbbVie, Hansen reports competing interests from Roche, and Loft, and Hetland reports competing interests from AbbVie, BMS, MSD, Pfizer, Roche and UCB.

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Reference

Glintborg B, Sørensen IJ, Loft AG, et al. A nationwide non-medical switch from originator infliximab to biosimilar CT-P13 in 802 patients with inflammatory arthritis: 1-year clinical outcomes from the DANBIO registry [published online May 4, 2017]. Ann Rheum Dis. doi:10.1136/annrheumdis-2016-210742