Efficacy, safety and immunogenicity of the biosimilar etanercept compared to the reference formulation original etanercept in patients with rheumatoid arthritis: An open-label, randomized, comparative, multicenter study.

BACKGROUND: The objective of this phase III clinical randomized trial was to establish the therapeutic equivalence of biosimilar etanercept (bio-etanercept) with original etanercept (O-etanercept) for patients diagnosed with rheumatoid arthritis. METHODS: The study (NCT04079374) enrolled patients with moderate to high disease activity rheumatoid arthritis. Enrolled patients were randomized 1:1 into 2 treatment groups, 1 receiving bio-etanercept (study drug) and the other receiving O-etanercept (comparator) at a dose of 25mg twice weekly, for 24 weeks. The primary efficacy endpoint was the number of patients with an ACR20 response after 24 weeks of treatment. Safety (adverse reaction/adverse event) and immunogenicity of both drugs were evaluated. RESULTS: Among 156 patients (79 in the bio-etanercept group and 77 in the O-etanercept group) who completed 24-week treatment and 4-week follow-up, 82.3% (65 patients) and 90.9% (70 patients) achieved an ACR20 response in the bio-etanercept and O-etanercept groups, respectively. There was no significant difference between the 2 groups (P = .16). No significant differences in the occurrence of adverse reactions/adverse events were found between the 2 groups regardless of severity (P = .63 for mild, P = .43 for moderate and P > .99 for severe). The development of antibodies in the bio-etanercept group was observed in 4 (5.1%; visit 6), 4 (5.0%; visit 9), and 3 (3.8%; visit 11) patients, and in 5 (6.4%), 5 (6.5%), and 3 (4.1%) patients in the O-etanercept group. The differences between the 2 groups were not significant (P > .99). CONCLUSIONS: This study showed that bio-etanercept was equivalent to the reference formulation.