Efficacy and Safety Study of TAS5315 Compared With Placebo in Participants With Rheumatoid Arthritis.

Exclusion Criteria

• •Have been treated with conventional synthetic disease-modifying anti-rheumatic drug, except for MTX, within 28 days prior to randomization
• •Have an inadequate response to biologic disease-modifying anti-rheumatic drug or Have been treated with 2 biologic treatment
• •Have been treated with Janus Kinase inhibitors or other Bruton's Tyrosine Kinase inhibitors
• •Have a positive result for hepatitis B surface antigen/antibody, hepatitis B core antibody, hepatitis C virus antibody or human immunodeficiency virus antigen/antibody at screening
• •Have been treated with Oral steroids at dose above 10 mg/day of prednisone or prednisone equivalents
• •Have a diagnosis of Felty's syndrome
• •Have a positive result of the QuantiFERON®-tuberculosis (TB) Gold test or a T-spot ®-TB test at screening
• •Have a positive result of β-D-glucan at screening