High retention rates after switching between infliximab biosimilars

A Danish observational study revealed that retention rates after biosimilar-to-biosimilar infliximab switch is high among patients with rheumatic diseases in daily practice. Higher retention rates were observed in patients previously treated with the originator biologic.

As Dr Hafsah Nabi (Rigshospitalet, Denmark) pointed out, biosimilars play an important role in rheumatology, especially due to their economic advantage [1]. Evidence for their use is mainly based on randomised controlled trials. “We are missing data across indications in older age and in patients with complex comorbidities,” Dr Nabi said. In addition, data regarding the outcomes after switching from one infliximab biosimilar to a second one is limited.

Denmark is known for its biosimilar success. Since 2015, switches have been mandatory, at the beginning from the original product to a biosimilar, but later from 1 biosimilar to another. In her study, Dr Nabi assessed the effectiveness of switching infliximab biosimilars CT-P13 to GP1111 among patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA). Patients were analysed in 2 cohorts: those who had previously switched from the originator (originator-experienced) and those who were originator-naïve. Data from the DANBIO registry linked with national patient registries were used, the latter to identify comorbidities.

The main outcome measures in the 2 groups were 1-year GP1111 treatment retention and changes in disease activity 4 months before versus 4 months after the switch. The researchers also identified clinical factors at baseline associated with GP1111 treatment withdrawal.

Included were 1,605 patients (685 RA, 314 PsA, and 606 axSpA) with a median disease duration of 9 years, of which 1,171 were originator-naïve. The originator-naïve group tended to be younger, with lower disease duration, but higher disease activity.

One-year retention rates of GP1111 were 92% (95% CI 90-95%) in the originator-experienced and 83% (95% CI 81-85%) in the originator-naïve, respectively. Changes in disease activity 4 months pre- and post-switch were close to zero for all disease activity measures (e.g. Disease Activity Score in 28 joints [DAS28], Ankylosing Spondylitis Disease Activity Score [ASDAS], pain Visual Analogue Scale [VAS]).

Factors associated with higher GP1111 retention rates were being originator-experienced compared to originator-naïve in the fully adjusted cohort (HR=0.36; 95% CI 0.2-0.7) and lower disease activity at baseline.

“Overall, the 1-year retention rates after biosimilar-to biosimilar infliximab switch was high. Moreover, the disease activity remained stable 4 months before and after switch,” Dr Nabi summarised. The fact that retention was higher in originator-experienced patients and in patients with low disease activity suggests that outcomes are predominantly affected by patient- rather than drug-related factors.

 

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   1. Nabi H. Biosimilar-to-Biosimilar Switching in Routine Care – Results on >1,600 Patients with Inflammatory Arthritis in the DANBIO Registry. 1112, ACR Convergence 2022, 10–14 November, Philadelphia, USA.

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Posted on 1 December 202216 February 2024