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

Inclusion Criteria:

Subjects must satisfy the following criteria to be enrolled in the study:

1. Diagnosis of RA as defined by the 1987-revised ACR criteria.

2. RA, characterized by at least 6 out of 66 swollen joints and 6 out of 68 tender joints
at Screening and Baseline, and at least 2 of the following: a C reactive protein level
(CRP), greater than the upper limit of normal (ULN) ³ 1 mg/dl, an erythrocyte
sedimentation rate (ESR) of at least 28 mm per hour, or morning stiffness lasting
longer than 45 minutes.

3. Non responsive or intolerant to a minimum of 2 RA therapies which are classified as
DMARDs, biologics, or corticosteroids.

4. Biological medication must be discontinued 30 day prior to the first dose of study
drug, except golimumab and actemra which are 60 days, and infliximab, alefacept and
efalizumab, which must have been discontinued 90 days prior to the first dose of IP.

5. Cytotoxic agents, including but not limited to chlorambucil, cyclophosphamide,
nitrogen mustard, or other alkylating agents must have been discontinued 90 days prior
to the first dose of IP.

6. Subjects must be able to tolerate intravenous infusions in both arms.

7. There should be no change in RA medication dose anticipated during the initial
treatment and re treatment periods and the respective 12 week follow-up period for
each dosing treatment period. The following rules apply for anti-rheumatic medications
taken during the study:

8. DMARDs must have must have been stable for least 90 days prior to dosing with IP.

9. Low -dose corticosteroids are permitted (prednisolone ≤ 10 mg per day or equivalent).
Corticosteroids must have been stable for at least 30 days prior to dosing with IP.

10. DMARDs and corticosteroids must remain stable throughout the initial 3 months of study
and throughout subsequent treatment periods

The presence of any of the following will exclude a subject from enrollment:

1. Prior use of rituximab and other B-cell depleting therapies, abatacept, prior use of
more than 2 biologic therapies.

2. Subject has received an investigational agent in any indication-within 60 days (or 5
half-lives, whichever is longer) prior to treatment with IP.

3. Subject has received previous cell therapy.

4. Serum creatinine concentration > 2.0 mg/dl at screening.

5. Alkaline phosphatase > 2.5x the upper limit of normal at screening.

6. Bilirubin level > 1.5 mg/dL (unless subject has known Gilbert's disease).

7. Untreated chronic infection or treatment of any infection with antibiotics within 4
weeks prior to dosing with IP.

8. Positive HIV test at Screening. Positive Hepatitis B surface antigen at Screening.
Positive Hepatitis C antibody at Screening.

9. Organic heart disease (e.g., congestive heart failure), myocardial infarction within
six (6) months prior to screening or clinically significant findings on ECG at
screening. Clinically significant arrhythmia.

10. Primary or secondary immunodeficiency.