The objective of this study is to evaluate the safety and efficacy of ONO-4641 in patients with relapsing-remitting multiple sclerosis over a 26-week treatment period.

Inclusion Criteria:

• Adult male or female aged 18-55 years inclusive at screening
• Patients who have a definite diagnosis of relapsing-remitting Multiple Sclerosis

Exclusion Criteria:

• Multiple Sclerosis course other than relapsing-remitting multiple sclerosis
• History of malignancy
• History of clinically significant chronic disease of the immune system (other than Multiple Sclerosis)
• Inability to undergo Gd-enhanced MRI scans
• Diagnosis of diabetes mellitus (type I or type II)