Inclusion Criteria:
- Male or female participants between the ages of 18 and 70 years.
- Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures.
- Diagnosis of RA and meeting the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for RA with a Total Score ≥6/10.
- The participant has active disease at both Screening and Randomization, as defined by both: ≥6 joints tender or painful on motion, AND ≥6 joints swollen; and fulfills 1 of the following 2 criteria: High sensitivity C reactive protein (hsCRP) >7 mg/L at Screening (Visit 1) as performed by the central laboratory OR Erythrocyte sedimentation rate (ESR) (Westergren method) >28 mm h.
Exclusion Criteria:
- Other acute or chronic medical or psychiatric condition including recent (within the past year) or active suicidal ideation or behavior or laboratory abnormality that may increase the risk associated with study participation or IP administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study.
- Participants with a known immunodeficiency disorder or a first degree relative with a hereditary immunodeficiency.
- Participants with any active or latent infections.
- Participants with positive hepatitis B surface antigen (HBsAg).
- Participants with positive HCV Ab tests will be reflex tested for HCV ribonucleic acid (HCV RNA).
- Any history of either untreated or inadequately treated latent or active tuberculosis (TB) infection, current treatment for active or latent TB infection or evidence of currently active TB,
- History of a major organ transplant (eg, heart, lung, kidney and liver) or hematopoietic stem cell/marrow transplant.
- History of severe allergic or anaphylactoid reaction to kinase inhibitors, or corticosteroid preparations.
- Known history of diverticulitis or symptomatic diverticulosis, perineal abscess or fistulae.
- Participants with malignancy or history of malignancy (including lymphoma, leukemia, or lymphoproliferative disease).
- Pre-existing chronic autoimmune disease (eg, inflammatory bowel disease, systemic lupus erythematosus, moderate-severe atopic dermatitis, dermatomyositis) other than RA. Secondary Sjogren's Syndrome (due to RA) may be included.
- Participants with fibromyalgia will be excluded.
- Previous treatment with total lymphoid irradiation.
- Participants with an oral, tympanic, or temporal temperature of 38°C (100.4°F) or higher at baseline.
- Participants may not receive any live/attenuated vaccine from 30 days prior to randomization during the course of the study, or for 30 days after the last dose of study medication. Participants who have current routine household contact with children who have received varicella or oral polio vaccine within 2 months of first study dose are also excluded.
- History of any lymphoproliferative disorder.
- Have hearing loss with progression over the previous 5 years, sudden hearing loss, or middle or inner ear disease.
- History of any prior deep vein thrombosis (DVT) or pulmonary embolism [PE].
- Recent (within 6 months of screening) myocardial infarction, coronary revascularization, or percutaneous angioplasty with or without placement of a coronary artery stent; acute coronary syndrome; chronic uncompensated heart failure or New York Heart Association Functional Class III or IV; left ventricular assist devices; implanted defibrillators.
- Current severe chronic renal insufficiency or renal failure as defined by persistent (on repeated measurements) eGFR <60 mL/min per 1.73 m2 based on the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) calculation.
- Any known coagulopathy or hypercoagulant syndrome.
- Presence of any of the following laboratory abnormalities at screening or within the 3 months prior to first study dose:
Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels ≥1.5 x the upper limit of normal (ULN); Participants with a history of Gilbert's syndrome may have a direct bilirubin measured and would be eligible for this study provided the direct bilirubin is ≤ ULN and other liver function assessments are normal; Absolute neutrophil count of <1.5 x 109/L (<1500/mm3). Participants with cyclic (benign ethnic) neutropenia will be excluded; Absolute lymphocyte count of <0.5 x 109/L (<500/mm3); Absolute white blood cell (WBC) count of <3.0 x 109/L (<3000/mm3); Hemoglobin <9.0 g/dL (90 g/L); Platelet count ≤100 x 109/L (100,000 cells/mm3) or ≥1000 x 109/L (1,000,000 cells/mm3); Thrombocytopenia, as defined by a platelet count <100 x 109/L (<100,000/mm3) at screening visit or within the 3 months prior to first study dose. [Screening laboratory tests with abnormal results may be repeated once to confirm abnormal results. If results return to normal protocol acceptable limits within the 4-week screening period, the participant may enter the study].
- Grade 3 or greater laboratory abnormality based on the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 toxicity scale, except for the following that are allowed: Grade 3 prothrombin time (PT) secondary to warfarin treatment; Grade 3 partial thromboplastin time (PTT) due to lupus anticoagulant and not related to liver disease or anti-coagulant therapy.
- Participants previously treated with a biologic DMARD (except for up to 25% of participants who may have been treated with 1, and only 1 prior TNF inhibitor) or any other recent DMARD treatment (eg, a JAK inhibitor), or participants currently treated with any other prohibited medications will be excluded.
- Prior use of tofacitinib or other JAK inhibitor in the context of a clinical trial is excluded. Concomitant use of tofacitinib (other than as prescribed by the randomization scheme) or other JAK inhibitor is prohibited.
- Participants who have previously been treated with other, non-TNFa inhibiting biologic DMARDs [including, abatacept (Orencia®), tocilizumab (Actemra®), Sarilumab (Kevzara®), anakinra (Kineret®), rituximab (Rituxan®) or other selective B lymphocyte depleting agents, or other lymphocyte depleting agents/therapies (such as alemtuzab [CamPath®], natalizumab (Tysabri®), alkylating agents [eg, cyclophosphamide or chlorambucil], total lymphoid irradiation) are excluded from participation in the study.
- Previous administration with an investigational drug within 30 days (or as determined by the local requirement) or 5 half-lives preceding the first dose of IP used in this study (whichever is longer).
- Any 12-lead electrocardiogram (ECG) performed prior to randomization that demonstrates clinically relevant abnormalities that may affect participant safety or interpretation of study results.