Background Biosimilar biologic disease modifying anti-rheumatic drug (bsDMARD) are supposed to offer a real economic advantage for these diseases for the same health benefit. While the administration of a biosimilar to a new patient is widely accepted, the switch from a biologic originator DMARD (boDMARD) to its biosimilar remains questioned.
Objectives This study aimed to assess the safety and efficacy of switching from an IV anti-TNF boDMARD to its bsDMARD in patients with rheumatic arthritis, spondyloarthritis, psoriatic arthritis, juvenile arthrtitis and uveitis.
Methods Prospective real-life study in the rheumatology unit of La Pitié-Salpêtrière Hospital, from February 2016 to December 2016. Patients initially treated with the boDMARD infliximab (RemicadeÒ), all switched to infliximab bsDMARD (InflectraÒ) after patient's information by a rheumatology nurse. The dose and administration schedule remained unchanged at the switch. Our primary endpoint was infliximab maintenance rate. Secondary endpoints were evolution of disease activity, as well as evolution of both infliximab trough levels and anti-drug antibody (ADA) serum levels before and after the switch. In addition, safety events were also monitored.
Results We identified 89 patients – spondyloarthritis (61%), rheumatic arthritis (27%), psoriatic arthritis (11%), juvenile arthritis and uveitis (1%) – in rheumatology who have been switched to boDMARD infliximab to its bsDMARD. Clinical assessment was based on DAS28 (peripheral joint involvement) or BASDAI (axial involvement) scores. 93% of patients remained treated with infliximab: 6 patients (7%) stopped the treatment due to a loss of efficacy. As shown in Figure 1, there is no significant change in disease activity before and after having switched patients to infliximab biosimilar.The ADAdosage were detected in 10 patients, 7 with high titer (>200ng/mL) and 3 with moderate titer (between 50 and 200 ng/mL). It was significantly correlated with low trough levels of IFX (<0,3μg/mL). Among them, 6 (4 with high titer; 2 with moderate titer) also had a poor clinical response before switch (refractory patients). 4 ADA-positive patients (3 with high titer; 1 with moderate titer) were still good clinical responders.
Conclusions The interchangeability of infliximab boDMARD to its bsDMARD does not rise any efficacy and safety concern in our experience. The role of drug and ADA monitoring during the switch remains to be further explored.
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Disclosure of Interest None declared