Effectiveness of SB4 Transition from Originator Etanercept in Rheumatoid Arthritis and Axial Spondyloarthritis: A Subgroup Analysis from the BENEFIT Study

Objectives: The pan-European BENEFIT study of patients with stable rheumatoid arthritis (RA) or axial spondyloarthritis (axSpA) who transitioned from reference etanercept to SB4 found no clinically meaningful changes in disease control after transition. The analysis aims to illustrate the peculiarities of the Italian cohort of patients compared with the whole population to provide a more real-life approach to the data for the Italian rheumatologists, ruling out possible local confounding factors. Methods: A prospective study for up to 6 months following transition was conducted. Outcome measures of interest include clinical characteristics at time of transition and disease activity scores (Disease Activity Score-28 [DAS28] for RA, Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] for axSpA) over time and safety. Results: One-hundred and eleven subjects (out of the 557 in total enrolled in the study) were derived from 8 Italian sites, including 79 with RA and 32 with axSpA. In both cohorts, the efficacy was maintained at 3 months and 6 months from the transition to the biosimilar with no significant change in mean DAS28 and BASDAI scores: at the end of the 6 months of observation the mean DAS28 and BASDAI was similar to baseline (confidence interval [CI] -0.22, 0.22), while the mean variation of the BASDAI was -0.14. Of note, 100.0% (95% CI 89.1, 100.0) in the axSpA and 90.8% (95% CI 81.5, 95.5) in the RA cohort of patients continued to receive SB4 at month 6 (binary variable with 95% Clopper-Pearson CI). Conclusions: Italian patients with stable RA or axSpA who transitioned from originator Etanercept to SB4 maintained clinical response at 6 months post-transition. Both the cohorts are representative of typical patients with long-standing established diagnoses. Most of the patients transitioned to the same dose regimen of biosimilar as that received for the originator, and the regimen remained unchanged at 6 months, supporting the effectiveness of the transition.