Safety and Efficacy of MK-8457 and Methotrexate (MTX) in Patients With Active Rheumatoid Arthritis Despite MTX Therapy (MK-8457-008 AM6)

Country-Specific Amendments: Amendments 1, 2, and 4 (Brazil); Amendments 5 and 6 (Japan)

Inclusion Criteria:

- Diagnosis of rheumatoid arthritis for at least 6 months prior to screening

- Active rheumatoid arthritis as defined by the presence of >= 6 swollen joints (of 66
count) and >= 6 tender joints (of 68 joint count)

- C-reactive protein blood level >0.9 mg/dL

- Anti-citrullinated protein antibody positive and/or rheumatoid factor positive at
screening

- American College of Rheumatology Functional Class I, II, or III

- Received methotrexate for a minimum of 3 months prior to screening with a regionally
appropriate stable weekly dose for at least 4 weeks prior to screening

- If using oral corticosteroids, the participant must be on a stable dose of 10 mg
prednisone

- No history of either untreated, latent, or active tuberculosis prior to baseline

- Participants of reproductive potential must agree to remain abstinent or use 2
acceptable methods of birth control

Exclusion Criteria:

- Presence of inflammatory disease other than rheumatoid arthritis, including but not
limited to psoriatic arthritis, ankylosing spondylitis, systemic lupus erythematosus,
or Lyme disease

- Positive hepatitis B surface antigen or hepatitis C test result or the presence of
HIV infection

- Human immunodeficiency virus positive

- User of recreational or illicit drugs or has had a history (within the previous 2
years) of drug or alcohol abuse or dependence

- Females of childbearing potential who are pregnant, intend to become pregnant, or are
lactating