Safety and Efficacy of Orally Administered Laquinimod Versus Placebo for Treatment of Relapsing Remitting Multiple Sclerosis (RRMS)

Inclusion Criteria: 1. Subjects must have a confirmed and documented MS diagnosis as defined by the Revised McDonald criteria \[Ann Neurol 2005: 58:840-846\], with a relapsing-remitting disease course. 2. Subjects must be ambulatory with converted Kurtzke EDSS score of 0-5.5. 3. Subjects must be in a stable neurological condition and free of corticosteroid treatment \[intravenous (iv), intramuscular (im) and/or per os (po)\] 30 days prior to screening (month -1). 4. Subjects must have had experienced one of the following: * At least one documented relapse in the 12 months prior to screening * At least two documented relapses in the 24 months prior to screening * One documented relapse between 12 and 24 months prior to screening with at least one documented T1-Gd enhancing lesion in an MRI performed within 12 months prior to screening. 5. Subjects must be between 18 and 55 years of age, inclusive. 6. Subjects must have disease duration of at least 6 months (from the first symptom) prior to screening. 7. Women of child-bearing potential must practice an acceptable method of birth control \[acceptable methods of birth control in this study include: surgical sterilization, intrauterine devices, oral contraceptive, contraceptive patch, long-acting injectable contraceptive, partner's vasectomy or double-barrier method (condom or diaphragm with spermicide). 8. Subjects must be able to sign and date a written informed consent prior to entering the study 9. Subjects must be willing and able to comply with the protocol requirements for the duration of the study. Exclusion Criteria: 1. Subjects with progressive forms of MS 2. An onset of relapse, unstable neurological condition or any treatment with corticosteroids \[intravenous (iv), intramuscular (im) and/or per os (po)\] or ACTH between month -1 (screening) and 0 (baseline). 3. Use of experimental or investigational drugs, and/or participation in drug clinical studies within the 6 months prior to screening. 4. Use of immunosuppressive including Mitoxantrone (Novantrone®) or cytotoxic agents within 6 months prior to the screening visit. 5. Previous use of either of the following: natalizumab (Tysabri®), cladribine, laquinimod. 6. Previous treatment with glatiramer acetate (Copaxone®) Interferon-β (either 1a or 1b) or IVIG within 2 months prior to screening visit. 7. Systemic corticosteroid treatment of ≥30 consecutive days duration within 2 months prior to screening visit. 8. Previous total body irradiation or total lymphoid irradiation. 9. Previous stem cell treatment, autologous bone marrow transplantation or allogenic bone marrow transplantation. 10. A known history of tuberculosis. 11. Acute infection two weeks prior to baseline visit. 12. Major trauma or surgery two weeks prior to baseline 13. A history of vascular thrombosis (excluding catheter-site superficial venous thrombophlebitis). 14. A carrier state of factor V Leiden mutation (either homo- or heterozygous) as disclosed at screening. 15. Positive screening test for Hepatitis B surface antigen, Hepatitis C antibody, or HIV antibody as disclosed at screening visit. 16. Use of potent inhibitors of CYP3A4 within 2 weeks prior to baseline visit (1 month for fluoxetine) see detailed list in Appendix 5 17. Use of amiodarone within 2 years prior to screening visit. 18. Pregnancy or breastfeeding. 19. Subjects with a clinically significant or unstable medical or surgical condition that would preclude safe and complete study participation, as determined by medical history, physical examinations, ECG, laboratory tests or chest X-ray. Such conditions may include: * A cardiovascular or pulmonary disorder that cannot be well-controlled by standard treatment permitted by the study protocol. * A gastrointestinal disorder that may affect the absorption of study medication. * Renal or metabolic diseases. * Any form of chronic liver disease, including known non-alcoholic steatohepatitis. * A ≥2xULN serum elevation of either of the following at screening: ALT, AST or direct bilirubin * A QTC interval (obtained from either 2 ECG recordings at screening or from the mean value calculated from 3 measurements at baseline visit) which is \>450msec. * A family history of Long- QT syndrome. * A history of drug and/or alcohol abuse. * Major psychiatric disorder. 20. A known history of sensitivity to Gd. 21. Inability to successfully undergo MRI scanning. 22. Known drug hypersensitivity that would preclude administration of laquinimod, such as hypersensitivity to: mannitol, meglumine or sodium stearyl fumarate. Exclusion Criteria: 1. Subjects who suffer from any form of progressive MS. 2. Any condition which the investigator feels may interfere with participation in the study. 3. Subjects with a clinically significant or unstable medical or surgical condition that would preclude safe and complete study participation, 4. Subjects who received any investigational medication, immunosuppressives or cytotoxic agents within 6 months prior to screening 5. Previous treatment with immunomodulators within two months prior to screening 6. Pregnancy or breastfeeding.