A Multi-center Study a Single IV Infusion of Allogeneic MPCs in Patients With Rheumatoid Arthritis and Incomplete Response to at Least One TNFα Inhibitor

Inclusion Criteria: * Males and Females ages 18-80 years old * Active rheumatoid arthritis (RA) disease as per 2010 ACR/EULAR classification criteria for the diagnosis of RA. * Must be positive for rheumatoid factor and/or anti-cyclic citrullinated peptide (anti-CCP3) but without extra-articular disease or functional limitation * Patient with active RA defined as: * ≥ 4 tender joint count (TJC) 28 joint count at screening and * ≥ 4 swollen joint count (SJC) count 28 joint count at screening * ESR ≥ 28 mm/hr or hsCRP \>2.0 mg/L * Patient has been taking MTX for at least 4 months with dose and route of administration stable for at least 8 weeks prior to screening * Patient has had an inadequate response to at least one TNFα inhibitor with last dose at least 6 weeks prior to screening * Use of oral DMARD (sulfasalazine, hydroxychloroquine, chloroquine and leflunomide) is permitted but must be stable for at least 3 months prior to screening Exclusion Criteria: * Pregnant women or women who are breastfeeding. * Other investigational therapy received within 8 weeks or five half-lives (whichever is longer) prior to Screening (except as in exclusion #13). * Known or suspected alcohol or drug abuse within three years preceding Screening. * Autoimmune disease other than RA (such as systemic lupus erythematosus (SLE), mixed connective tissue disease, scleroderma, polymyositis/dermatomyositis, vasculitis) * History of or current inflammatory joint disease other than RA (such as tophaceous gout, reactive arthritis, psoriatic arthritis, ankylosing spondylitis or other spondyloarthropathy, Lyme disease). Patients primarily diagnosed with osteoarthritis are excluded. * Bedridden or confined to a wheelchair or patients with \> 3 arthroplasties due to RA. * History of diagnosed and/or treated malignancy with no evidence of recurrence in past 5 years * Surgical procedures planned to occur during the trial (these patients may be rescreened following completion of and recovery from the surgical procedure). * Use of TNFα inhibitor for treatment of RA at time of screening or within the 6 weeks prior to screening. * Prior use of biologic agent for treatment of RA within 6 weeks prior to screening