A Multicenter Study to Assess the Effect of Plasma Exchange in Accelerating the Clearance of Natalizumab in Subjects With Multiple Sclerosis (MS)

Inclusion Criteria:

considered by the Investigator to be free of signs and symptoms suggestive of any serious opportunistic infection
willing to discontinue and remain free from concomitant immunosuppressive or immunomodulatory treatment (including interferon beta and glatiramer acetate) for the duration of the study
willing and able to comply with the site's plasma exchange protocol which may require hospitalization or daily visits

Exclusion Criteria:

considered by the Investigator to be immunocompromised
history of, or available abnormal laboratory results indicative of any major disease that would preclude the administration of a recombinant humanized antibody immunomodulating agent for the duration of the study.
condition(s) considered to be contraindication(s) for plasma exchange, including but not limited to bleeding diathesis, hypotension, or vascular access limitations