This invention provides a method of predicting clinical responsiveness to laquinimod therapy in a subject afflicted with multiple sclerosis or presenting a clinically isolated syndrome comprising evaluating expression of a biomarker in the subject. This invention also provides a method of treating said subject comprising determining whether the subject is a laquinimod-responder by evaluating expression of a biomarker. Also provided is laquinimod or a pharmaceutical composition comprising laquinimod for use in treating said subject, and a therapeutic package for use in dispensing to said subject, wherein the subject has been identified as a laquinimod-responder or expression of a biomarker in the subject is up-regulated or suppressed.