Introduction: YLB113 is a biosimilar of the reference product (RP), etanercept, under development for treatment of patients with moderate-to-severe rheumatoid arthritis (RA) and other approved indications. A phase 3 study was conducted in Europe, Japan, and India to compare the efficacy, safety, and immunogenicity of YLB113 with the RP over a treatment period of 52 weeks.
Methods:Overall, 528 patients with moderateto-severe RA receiving concomitant methotrexate were randomized to receive a once-weekly, subcutaneous dose of 50 mg YLB113 or the RP. The primary endpoint was ACR20 response rate at week 24, with similarity confirmed if the 95% confidence interval (CI) for YLB113 and the RP was within the range of -15 to 15%. Safety and immunogenicity endpoints were assessed to week 52. Results: Based on the European analysis, in the full analysis set, ACR20 response at week 24 was 83.3% and 88.5% for YLB113 and the RP, respectively. Responses were within the predefined clinical equivalence margin. The sensitivity analysis in the per protocol set revealed a similar proportion of subjects exhibiting ACR20 response at week 24 between groups, with a difference of -5.1% (95% CI -11.07 to 0.81).