Study discontinued based on planned interim analysis of the primary endpoint. Not linked to any safety concern.

Primary Objectives:

• To assess the efficacy of vatelizumab compared to placebo as measured by a reduction in new contrast-enhancing lesions (CELs) in relapsing remitting multiple sclerosis (RRMS) patients.
• To evaluate multiple doses of vatelizumab for a dose-response.

Secondary Objectives:

• To evaluate the safety and tolerability of vatelizumab compared to placebo.
• To evaluate the pharmacokinetics (PK) of vatelizumab.

The duration of study per patient will be up to 108 weeks, including a screening period of up to 4 weeks, a treatment period of 12 weeks and a post-treatment safety follow-up period of up to 92 weeks.

Patients completing the 12-week treatment period may enter an optional long-term extension study in which all subjects will receive vatelizumab.

Inclusion criteria:

Diagnosis of relapsing-remitting multiple sclerosis (RRMS). At least 1 documented relapse in the past 12 months. At least 1 contrast-enhancing lesion (CEL) on magnetic resonance imaging (MRI) in the past 12 months and/or at screening.

At least 3 T2 lesions on screening MRI.

Exclusion criteria:

Diagnosis of primary progressive or secondary progressive MS. Expanded disability status scale (EDSS) score >5.5. Relapse within 30 days prior to enrollment. Prior immunosuppressive treatment within protocol-specified time periods. Prior treatment with natalizumab (Tysabri®). History of bleeding/platelet disorders, malignancy, certain infections as defined in the protocol, or any other past or current medical conditions that would adversely affect the patient's participation in the study.

Pregnancy or breast-feeding. Other protocol-defined inclusion/exclusion criteria may apply.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.