Pharmacodynamic Study to Better Understand the Therapeutic Response and Immunomodulatory Effects of Avonex in Multiple Sclerosis (MS) Patients and Healthy Volunteers

Inclusion Criteria: Healthy Control Subjects (Group 1) * Must be in general good health. * Must not have received interferons in the past. All MS Subjects * Clinical or laboratory-supported diagnosis of relapsing remitting MS (McDonald et al, criteria numbers 1-4). * Either on AVONEX® or treatment-naïve. * Have an EDSS score between 0.0 and 5.5, inclusive. Exclusion Criteria: * History of severe allergic or anaphylactic reaction or hypersensitivity to human albumin, to any interferon, to other components of the drug formulation. * History of intolerance to acetaminophen, ibuprofen, naproxen, and aspirin that would preclude the use of at least one of these during the study. * History of any clinically significant (as determined by the investigator) cardiac, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, renal, and/or other major disease. * History of malignancy. * The presence of any significant medical condition or psychiatric illness not due to MS that, in the investigator's opinion, would interfere with therapy * History of uncontrolled seizures within the 3 months prior to enrollment. * History of suicidal ideation or an episode of severe depression within the 3 months prior to enrollment. * Serious local infection (e.g., cellulitis, abscess) or systemic infection (e.g., pneumonia, septicemia) within 8 weeks prior to enrollment. * Positive for human immunodeficiency virus (HIV), hepatitis C antibody (HCV) or positive for hepatitis B surface antigen (HbsAg) at screening. Other inclusion and exclusion criteria apply as per protocol