A Study of the Safety, Pharmacokinetics, and Pharmacodynamics of MTRX1011A in Patients With Rheumatoid Arthritis

Inclusion Criteria:

1. SAD Stage

   • RA diagnosed according to the ACR
   • For patients taking anti-rheumatic therapies, receipt of a stable regimen prior to randomization
   • Previous treatment with biologic agents, including anti-TNF agents, permitted but discontinued for an appropriate washout period

2. MAD Stage (same as above with the addition of the following)

   • Failure of at least one biologic agent, defined as lack of or loss of response or intolerance
   • Active disease defined by swollen and tender count

Exclusion Criteria:

• Significant systemic involvement of RA, including vasculitis, pulmonary fibrosis, or Felty's syndrome
• Malignancy, or prior malignancy, other than non-melanoma skin cancer or cervical carcinoma in situ that has been resected
• History of treatment with any T cell-directed therapy