This Phase 3 study is intended to provide evidence that CP-690,550 dosed 5 mg BID and 10 mg BID is safe and effective when used in combination with a variety of traditional disease modifying antirheumatic drugs in adult patients with rheumatoid arthritis. It is intended to confirm the benefits of CP-690,550 in improving signs and symptoms and physical function that were observed in the Phase 2 rheumatoid arthritis studies.

• Drug: CP-690,550
  Film coated tablet, 5 mg po BID, 1 year
• Drug: CP-690,550
  Film coated tablet, 10 mg po BID, 1 year
• Drug: Placebo
  Film coated tablet, 1 tablet po BID, 3-6 months

• Active 5 mg: Experimental
  Intervention: Drug: CP-690,550
• Active 10 mg: Experimental
  Intervention: Drug: CP-690,550
• Placebo Sequence 1: Placebo Comparator
  Placebo non-responders advance to 5 mg CP-690,550 at Month 3 visit. All patients in this treatment arm advance to 5 mg CP-690,550 at Month 6 visit.
  Intervention: Drug: Placebo
• Placebo Sequence 2: Placebo Comparator
  Placebo non-responders advance to 10 mg CP-690,550 at Month 3 visit. All patients in this treatment arm advance to 10 mg CP-690,550 at Month 6 visit.
  Intervention: Drug: Placebo

Inclusion Criteria:

• The patient has a diagnosis of Rheumatoid Arthritis based on the American College of Rheumatology (ACR) 1987 Revised Criteria.
• The patient has active disease as defined by both >=4 tender or painful joints on motion and >= 4 joints swollen; and either an erythrocyte sedimentation rate (ESR) > 28 mm or a C-reactive protein (CRP) concentration > 7 mg/dL.
• Patient had an inadequate response to at least one disease modifying antirheumatic drug (traditional or biologic) due to lack of efficacy or toxicity.
• Patient must remain on at least one background traditional disease modifying antirheumatic drug.
• No evidence of inadequately treated latent or active infection with Mycobacterium tuberculosis.

Exclusion Criteria:

• Blood dyscrasias including confirmed: Hemoglobin <9 g/dL or Hematocrit <30%; White blood cell count <3.0 x 109/L; Absolute neutrophil count <1.2 x 109/L; Platelet count <100 x 109/L.
• History of any other rheumatic autoimmune disease other than Sjogren's syndrome.
• No malignancy or history of malignancy.
• History of infection requiring hospitalization, parenteral antimicrobial therapy, or as otherwise judged clinically significant by the investigator, within the 6 months prior to the first dose of study drug.