A Study to Evaluate Efficacy, Safety, and Tolerability of 6-Week Extended Interval Dosing of Natalizumab (BG00002) in Participants With Relapsing-Remitting Multiple Sclerosis (RRMS) Switching From Treatment With 4-Week Natalizumab Standard Interval Dosing (SID) in Relation to Continued SID Treatment

Key Inclusion Criteria:

- Ability of the participant to understand the purpose and risks of the study and
provide signed and dated informed consent and authorization to use confidential health
information in accordance with national and local participant privacy regulations.

- Diagnosis of relapsing remitting multiple sclerosis (RRMS) according to the McDonald
criteria [Thompson 2018].

- Treatment with natalizumab as disease-modifying monotherapy for RRMS that is
consistent with the approved dosing for a minimum of 12 months prior to randomization.
The participant must have received at least 11 doses of natalizumab in the 12 months
prior to randomization with no missed doses in the 3 months prior to randomization.

- Expanded Disability Status Scale (EDSS) <=5.5 at screening.

- No relapses in the last 12 months prior to randomization, as determined by the
enrolling Investigator.

Key Exclusion Criteria:

- Primary and secondary progressive multiple sclerosis (MS).

- MRI positive for Gd-enhancing lesions at screening.

- Participants for whom MRI is contraindicated (e.g., have a contraindicated pacemaker
or other contraindicated implanted metal device, have suffered, or are at risk for,
side effects from Gd, or have claustrophobia that cannot be medically managed).

- History of any clinically significant (as determined by the Investigator) cardiac,
endocrinologic, hematologic, hepatic, immunologic, metabolic (including diabetes),
urologic, pulmonary, neurologic (except for RRMS), dermatologic, psychiatric, renal,
or other major disease that would preclude participation in a clinical study, in the
opinion of the Investigator.

- Presence of anti-natalizumab antibodies at screening. NOTE: Other protocol defined
Inclusion/Exclusion criteria may apply