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