A Pharmacokinetic (PK) Study of Natalizumab (Tysabri) at Steady State

Exclusion Criteria

• •History of, or abnormal laboratory results indicative of, any clinically significant cardiac, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, gastrointestinal, dermatologic, psychiatric, and renal, or other major disease, as determined by the Investigator.
• •Positive result for antibodies to Tysabri at any prior evaluation.
• •Treatment with an investigational product or approved therapy for investigational use within 6 months prior to the start of PK sample collection or during the course of this study. Concurrent participation in an observational study (e.g., Tysabri Global Observational Program in Safety \[TYGRIS\]) is permitted.
• •Pre-scheduled for any elective procedure or medical treatment during the study period.
• •History of drug or alcohol abuse (as defined by the Investigator) within 2 years prior to the Screening Visit.
• •Female subjects who are breastfeeding, pregnant, or planning to become pregnant while on study.
• •Alcohol use within 24 hours prior to the Baseline Visit.
• •Inability or unwillingness to comply with study requirements, including the presence of any condition (e.g., physical, mental, social) that is likely to affect the subject's ability to comply with the study protocol.
• •Other unspecified reasons that, in the opinion of the Investigator or Biogen Idec, make the subject unsuitable for enrollment.