Study of Human Placenta-derived Cells (PDA001) to Evaluate the Safety and Effectiveness for Patients With Active Rheumatoid Arthritis

Dose escalation study: Subjects will be assigned to 1 of 2 treatment groups (1 unit or 4 units vs. vehicle control) based on the order in which they enroll in the study. Intravenous infusion will be administered on days 0 and 7. Nonresponders will be unblinded after 12 weeks of study. Non- responders on vehicle control will be re-dosed with the active PDA001 dose assigned at baseline (2 infusions, 7 days apart). Nonresponders taking active PDA001 will enter the safety follow-up portion of the study. Responders at 12 weeks will continue in the safety and efficacy follow-up portion of the study until 12 months of study. Responders will be treated for RA flare between 3-9 months of study with the active PDA001 dose assigned at baseline (2 infusions, 7 days apart).

"Cohort Dose Level 1: 4 units vehicle controlled placebp infused on Day 0 and Day 7~Cohort Dose Level 2: 4 units vehicle controlled placebo infused on Day 0 and Day 7"