A Study to Evaluate Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of Multiple Doses of Natalizumab (BG00002) Administered Subcutaneously to Japanese Participants With Relapsing-Remitting Multiple Sclerosis

Key Inclusion Criteria:

• Must have had a diagnosis of RRMS, as defined by the revised 2017 McDonald'scriteria. All other possible neurologic diagnoses must have been reasonably excludedby means of laboratory and/or imaging studies, in the opinion of the investigator.

• Must have had an EDSS score between 0.0 and 5.5, inclusive.

• Must have had screening MRI or documentation of an MRI within the participant'smedical record within 12 months of the screening visit that revealed 3 or more T2hyperintense lesions consistent with MS.

• Was born in Japan, and biological parents and grandparents were of Japanese origin.

Key Exclusion Criteria:

• Evidence of current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)infection within 14 days prior to Screening, between screening and baseline visit,or at baseline visit, including but not limited to a fever (temperature > 37.5degrees Celsius [°C]), new and persistent cough, breathlessness, or loss of tasteand/or smell.

• Have close contact within 14 days prior to Day 1 with a SARS-CoV-2 positiveindividual.

• Diagnosis of primary progressive MS or secondary progressive MS.

• An MS exacerbation (relapse) within 30 days prior to enrolment or, in the opinion ofthe investigator, the participant not having stabilized from a previous relapseprior to enrolment (Day 1).

• The participant is unable to have a brain MRI scan (e.g., a participant with a metalclip to repair a cerebral aneurysm).

• Previous exposure to natalizumab.

Note: Other protocol specified Inclusion/Exclusion criteria may apply.