Etanercept is a dimeric genetic recombinant glycoprotein consisting of Fc domain of human Immunoglobulin G1 and the extracellular domain of human tumor necrosis factor (TNF) receptor type II. Etanercept exerts therapeutic effects on inflammatory diseases such as rheumatoid arthritis and juvenile idiopathic arthritis by neutralizing biological activities of TNFα/Lymphotoxin (LT) α. Mochida Pharmaceutical and LG Chem have developed syringe, pen, and vial products of Etanercept BS (biosimilar) as the first biosimilar of Enbrel in Japan. The active ingredient of those products "Etanercept biosimilar 1" has the identical primary structure to that of Enbrel. The development of the Etanercept BS, including evaluations of quality attributes, nonclinical and clinical studies was performed in accordance with "Policies on Assurance of Quality, Safety and Efficacy of Biosimilars". The quality attributes of Etanercept BS were similar to those of Enbrel, and the binding affinities to TNFα/LTα, TNFα neutralizing activity, nonclinical pharmacokinetics and toxicological profiles of Etanercept BS were comparable to Enbrel. Additionally, the pharmacokinetic profile and efficacy of Etanercept BS were equivalent to those of Enbrel and there was no clinically significant difference in safety profiles between them in Phase I and Phase III clinical studies. The marketing approval application of the Etanercept BS with the same indications as Enbrel filed by Mochida Pharmaceutical was approved in January 2018 and the products will be launched by Ayumi Pharmaceutical in the near future. The Etanercept BS, which is as highly effective as Enbrel is expected to make beneficial therapies more easily accessible to patients.