A Phase 2 Clinical Study in Subjects With Primary Progressive Multiple Sclerosis to Assess the Efficacy, Safety and Tolerability of Two Oral Doses of Laquinimod Either of 0.6 mg/Day or 1.5mg/Day (Experimental Drug) as Compared to Placebo

Due to serious cardiovascular adverse events, Data Monitoring Committee (DMC) made a recommendation to stop all laquinimod treatment arms above 0.6 mg in the multiple sclerosis (MS) trials; therefore the 1.5 mg treatment arm in the ARPEGGIO study was discontinued as of 01 January 2016. The DMC did not identify any definite cardiovascular risk in the 0.6 mg treatment arm, but felt that long term monitoring for emergence of any potential signal was necessary. Therefore, the 0.6 mg treatment arm was continued while the sponsor closely monitored cardiovascular events in all laquinimod studies. Prior to 01 January 2016, eligible patients were randomized in a 1:1:1 ratio into 1 of the following treatment arms (a total of 286 patients were randomized 1:1:1 prior to 01 January 2016): * Laquinimod 0.6 mg daily * Laquinimod 1.5 mg daily * Daily placebo As of 01 January 2016, following the decision to discontinue the laquinimod 1.5 mg dose arm, additional eligible patients (87 patients) who were enrolled were randomized in a 1:1 ratio into one of the following treatment arms: * Laquinimod 0.6 mg daily * Daily placebo