A Dose Response Study to Evaluate the Efficacy and Safety of Oral AP1189 Administered in Disease-Modifying Anti-Rheumatic Drug (DMARD) naïve Participants Participants With Early Rheumatoid Arthritis

Exclusion Criteria23

• Functional class IV of Global Functional Status in RA, as defined by the ACR Classification.
• Rheumatic autoimmune disease other than RA, i.e. systemic lupus erythematosus, mixed connective tissue disease, scleroderma, polymyositis, or significant systemic involvement secondary to RA.
• Current inflammatory joint disease other than RA.
• Non-inflammatory type of musculoskeletal condition that in the Investigator's opinion is symptomatic and/or severe enough to interfere with the subject's primary diagnosis of RA or the evaluation of the effect of the study drug.
• Gastrointestinal diseases known to interfere with the absorption or excretion of medications.
• Severe, progressive, or uncontrolled renal, hepatic, hematologic, gastrointestinal, metabolic, endocrine, pulmonary, cardiac or neurologic disease.
• Malignancy active during the 12 months preceding the Screening Visit.
• Acute hepatitis, chronic hepatitis, or detection of any unexplained elevation of serum ALT or AST greater than 1.5-fold ULN, at least twice in the 6 months before the Screening Visit) or HIV infection.
• History of alcohol or drug abuse during the 12 months preceding the Screening Visit.
• Vaccination with live vaccines during the 6 weeks preceding the Screening Visit.
• Haemoglobin \<9 g/dL or Haematocrit \<30% at the Screening Visit
• White blood cell (WBC) count \<3.0 x 109/L at the Screening Visit.
• Absolute neutrophil count \<1.2 x 109/L at the Screening Visit.
• Platelet count \<100 x 109/L at the Screening Visit.
• Serum alkaline-phosphatase, or gamma-glutamyl-transferase greater than 3-fold ULN; alanine aminotransferase, or aspartate aminotransferase, or total bilirubin greater than 2-fold ULN At the Screening Visit.
• Estimated creatinine clearance less than 45 mL/min/1.73 m2 (MDRD) at the Screening Visit.
• lead electrocardiogram (ECG) with abnormal clinically significant findings, as judged by the Investigator, at the Screening Visit.
• Positive QuantiFERON-in-Tube test (QFG-IT).
• Use of hydroxychloroquine during the 30 weeks preceding the Screening Visit.
• Treatment with any systemic or intraarticular corticosteroid within 6 weeks before the Screening Visit.
• Intermittent use of nonsteroidal anti-inflammatory drugs (NSAIDs). Use of NSAIDs is allowed if used in a stable dose regimen for at least 4 weeks prior to the Screening Visit.
• Use of other investigational drugs/treatments, or enrolment in a clinical trial during the 6 months preceding the Screening Visit.
• Any other clinically relevant disease and condition that, in the opinion of the Investigator, may jeopardize efficacy or safety assessments or may compromise the subject's safety during trial participation.