Oral CF101 Tablets and Methotrexate Treatment in Rheumatoid Arthritis Patients

Inclusion Criteria: * Males and females ages 18-75 years * Meet the criteria of the American College of Rheumatology for RA (Arnett FC et al. Arthritis Rheum 1988;31:315-324; refer to Appendix 1. diagnostic criteria for Rheumatoid Arthritis) * Not bed- or wheelchair-bound * Active RA, as indicated by the presence of (a) \>=6 swollen joints (28 joint count); AND (b) \>=6 tender joints (28 joint count); AND either: (c) Westergren ESR of \>=28 mm/hour; OR (d) CRP level above the upper limit of normal for the central reference laboratory * Treatment with weekly oral or parenteral methotrexate for \>=6 months prior to baseline * Methotrexate route of administration has been unchanged for \>=2 months prior to baseline * Dose of methotrexate has been stable at 15-25 mg/week for \>=2 months, and is expected to remain stable throughout the study; the stable dose of methotrexate may alternatively be 10-12.5 mg/week if documented toxicity has precluded a higher dose * If taking hydroxychloroquine or chloroquine, administration duration has been for \>=3 months and dose has been stable for \>=2 months prior to baseline * If taking a nonsteroidal anti-inflammatory agent (NSAID), dose has been stable for at least 1 month prior to baseline, and will remain unchanged during protocol participation * If taking an oral corticosteroid, dose is \<10 mg/day prednisone or equivalent, has been stable for at least 1 month prior to the stabilization period, and will remain stable through the stabilization and entire treatment and follow-up period * Negative screening serum pregnancy test for female patients of childbearing potential * Females of childbearing potential must utilize, throughout the course of the trial, 2 methods of contraception deemed adequate by the Investigator (for example, oral contraceptive pills plus a barrier method) Exclusion Criteria: * Receipt of any of the following for at least a 1 month stabilization period prior to dosing: sulfasalazine, oral or injectable gold, azathioprine, minocycline, penicillamine, anakinra * Receipt of etanercept for at least a 6 week period prior to dosing * Receipt of cyclosporine, infliximab or adalimumab for at least a 2 month period prior to dosing * Receipt of leflunomide for at least a 2 month period prior to screening, unless patient has undergone cholestyramine washout at least 1 month prior to dosing * Receipt of cyclophosphamide for at least a 6 month period prior to dosing * Receipt of rituximab at any previous time * Participation in a previous trial CF101 trial * Use of oral corticosteroids \>10 mg of prednisone, or equivalent, per day * Change in NSAID dose level for 1 month prior to dosing * Change in oral corticosteroid dose level during the 1 month prior to, or during, the stabilization period vChange in hydroxychloroquine or chloroquine dose level during the 2 months prior to, or during, the stabilization period * Receipt of parenteral or intra-articular corticosteroids during the 1 month prior to, or during, the stabilization period * Significant cardiac arrhythmia or conduction block, congestive heart failure, or any other evidence of clinically significant heart disease; other clinically significant findings on screening electrocardiogram (ECG) * Hemoglobin level \<9.0 gm/dL at the screening visit * Platelet count \<125,000/mm3 at the screening visit * White blood cell count \<3000/mm3 at the screening visit * Serum creatinine level outside the central laboratory's normal limits at the screening visit * Liver aminotransferase (ALT and/or AST) levels greater than 1.25 times the central laboratory's upper limit of normal at the screening visit * Significant acute or chronic medical or psychiatric illness that, in the judgment of the Investigator, could compromise patient safety, limit the patient's ability to complete the study, and/or compromise the objectives of the study