The study aims to compare the effect of daily oral treatment of laquinimod capsules 0.6 mg with the effect of placebo capsules (capsules that contain no active medication) as well as with the effect of an existing MS injectable drug: Interferon β-1a (Avonex®).

• Drug: laquinimod
• Drug: placebo
• Drug: Interferon β-1a (Avonex®)

• Experimental: 0.6 mg Laquinimod oral once daily
• Placebo Comparator: oral placebo once daily
• Active Comparator: Interferon β-1a (Avonex®) 30 mcg IM once weekly

Inclusion Criteria:

1. Willing and able to give written informed consent
2. Confirmed MS diagnosis as defined by the McDonald criteria
3. R-R MS disease course
4. Subjects must be in a stable neurological condition and free of corticosteroid treatment
5. Women of child-bearing potential must practice a reliable method of birth control
6. Must understand the requirements of the study and agree to comply with the study protocol

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