This is a multicenter, randomized, double-blind phase2 study to evaluate the safety and investigate the efficacy of YRA-1909 in Patients with Rheumatoid Arthritis who are on a stable dose of Methotrexate(MTX) and who have an inadequate response to MTX(MTX-IR).

Inclusion Criteria:

• 19 Years to 80 Years
• Subjects with onset RA classified by ACR/EULAR 2010 revised classification criteria at least 12 weeks prior to screening
• Subjects meet the ACR 1992 Revised Criteria for the Classification of Global Functional Status in RA Class I, II or, III at screening

Exclusion Criteria:

• Subjects meet the ACR 1992 Revised Criteria for the Classification of Global Functional Status in RA Class Ⅳ at screening

• Any of the following laboratory values at screening:

  1. Patients with severe liver impairment (AST or ALT > 2 times the upper limit of normal)
  2. Patients with renal disease,immunodeficiency disease and peptic ulcer
  3. Patients with pleural effusion and ascites