In this clinical study, the safety and tolerability of GNbAC1 as a treatment for MS patients will be evaluated in healthy male volunteers.

The monoclonal antibody, GNbAC1, targets the envelope protein (Env) of the human endogenous retrovirus (HERV), also called multiple sclerosis associated retrovirus (MSRV), which is considered as a critical factor in the development of multiple sclerosis.

This study will assess the pharmacokinetics, safety and tolerability of GNbAC1 following single ascending doses (6, 18, and 36 mg/kg) administered via IV infusion.

Inclusion Criteria:

• Healthy male subjects as determined by past medical history, physical examination, vital signs, ECG and laboratory tests at Screening and confirmed at Day -1 who have signed the informed consent.
• Aged from 18 to 55 years, both inclusive.

Exclusion Criteria:

• History of serious adverse reactions or hypersensitivity to any drug.
• Presence or history of any allergy requiring acute or chronic treatment (seasonal allergic rhinitis that requires no treatment may be tolerated).
• Need of any prescription medication within 15 days prior to the administration of the study drug and/or non-prescription medication within 7 days prior to the administration of the study drug or anticipated need for any concomitant medication during the study.
• Participation in a clinical trial during the previous 3 months, i.e. from completion of the previous trial to the planned first administration of the current trial.

NOTE: Other protocol-defined Inclusion/Exclusion criteria may apply.