Characteristics and outcomes of rheumatoid arthritis patients who started biosimilar infliximab.

To compare the characteristics of rheumatoid arthritis (RA) patients receiving either biosimilar or originator infliximab and to identify the effectiveness and safety of biosimilar infliximab in RA patients in real-world practice. RA patients who started either biosimilar or originator infliximab were selected using the prospective biologic disease-modifying anti-rheumatic drugs (DMARDs) registry: BIOlogics Pharmacoepidemiologic StudY (BIOPSY). Baseline characteristics of the two groups were compared, and short-term treatment outcomes, including DAS28-ESR and HAQ-DI scores, were compared after initiation of biosimilar or originator infliximab. The drug retention rates of the two groups were also compared. A total of 100 RA patients, 55 biosimilar, and 45 originator infliximab users were included in this analysis. Baseline characteristics of age, disease duration, and previous or current medications were similar in the two groups. Baseline DAS28-ESR was higher in the originator infliximab group (6.3 ± 1.1 vs. 5.8 ± 1.1, p = 0.02). The early DAS28-ESR remission rates observed 7.9 ± 1.8 months after starting biosimilar and originator infliximab were 15.0 and 25.0%, respectively (p = 0.47). The change in HAQ-DI did not differ between the two groups (0.4 ± 0.7 vs. 0.4 ± 0.8, p = 0.94). Patients treated with biosimilar infliximab in clinical practice had lower disease activity at the start of treatment than those receiving originator infliximab. Biosimilar infliximab was well-tolerated, safe, and of similar clinical effectiveness to originator infliximab. Larger number of patient and longer follow-up data will be needed to confirm the effectiveness and safety of biosimilar infliximab in clinical practice.