Efficacy, safety and immunogenicity of the biosimilar etanercept compared to the reference formulation original...

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.

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.

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).

This study showed that bio-etanercept was equivalent to the reference formulation.