Study to Evaluate Efficacy, Safety and Tolerability of JTE-051 in Subjects With Active Rheumatoid Arthritis

Inclusion Criteria:

- A diagnosis of RA prior to the Screening Visit.

- Active disease despite ongoing therapy with up to two non-biologic disease-modifying
anti-rheumatic drugs, including methotrexate at both the Screening and Baseline
Visits.

- Screening hs-CRP ≥1.2 x upper limit of normal (ULN).

Exclusion Criteria:

- Prior/current exposure to biologic and/or kinase inhibitor therapy.

- Known history or presence of polyneuropathy of any cause and no presence of clinically
active compression neuropathy, radiculopathy or plexopathy at the Screening Visit.

- Positive test results for human immunodeficiency (HIV) virus, hepatitis B virus or
hepatitis C (HCV) virus at the Screening Visit.

- Positive drug of abuse and alcohol test results.

- History of a clinically-significant infection that required oral antimicrobial or
antiviral therapy within 8 weeks prior to Day 1.