A Study to Compare Efficacy, Pharmacokinetics, Safety and Immunogenicity of MB04 [proposed Etanercept Biosimilar] to Enbrel® [EU-sourced] in Rheumatoid Arthritis

The study will randomize approximately 458 patients aged between 18 and 75 years with active Rheumatoid Arthritis despite methotrexate therapy.

All patients shall receive methotrexate for ≥12 weeks and on a stable dose (10 to 25 mg/week) for ≥8 weeks prior to randomization, and folic acid (≥5 mg/week) from 4 weeks prior to screening until the end of the treatment period (Week 36).

Screening evaluations will be completed within 28 days prior to randomization. There will be 2 periods in the study: Main Treatment period and Transition period.

During the Main Treatment Period, eligible patients will be randomized, at a 1:1 ratio, to administer a 50 mg weekly dose of MB04 or EU- sourced Enbrel® subcutaneously (SC) using an Interactive Response System (IRT). After completing Week 24 assessment, patients will continue to receive the study treatment up to Week 36. Those patients who were originally assigned to EU-sourced Enbrel® will be randomized, at a 1:1 ratio, to receive either MB04 or EU-sourced Enbrel® SC, while patients originally assigned to MB04 will continue with the same treatment until Week 36.

After treatment discontinuation, patients will undergo a Safety follow-up period for 4 weeks, up to week 40.