Controlled High Risk AVONEX® Multiple Sclerosis Prevention Study In Ongoing Neurological Surveillance

The primary objective of this study is to determine the impact of long term AVONEX® treatment on physical status, measured by expanded disability scale score (EDSS), of patients with Multiple Sclerosis (MS) after their first clinical event (clinically isolated syndrome) and Magnetic Resonance Imaging (MRI) consistent with MS.

Secondary objectives are to determine the impact of long term therapy with AVONEX® on the following:

a) MRI parameters- new or enlarging T2 lesions, T2 lesion volume, T1 lesion volume, brain parenchymal fraction (BPF) b) Quality of Life (QoL): Heath Status Questionnaire (SF-36) c) Symbol Digit Modality Test (SDMT)

2. To determine the long term impact of therapy on the following in patients treated at the onset of clinically isolated event (CIS)

EDSS
MRI parameters
SF-36

SDMT

3. To determine early clinical and MRI predictors of disease progression.

Approximately 383 patients participated in CHAMPS, the original AVONEX® placebo trial, will be approached for study participation. The patient population will be divided into two cohorts.

Cohort 1: Patients that participated in CHAMPS and CHAMPIONS 10 will be approached for study participation at approximately twenty-four CHAMPIONS Continuation investigative sites.

Cohort 2: Patients that participated in CHAMPS will be located and approached for study participation. Patient that participated in CHAMPIONS 10 will not be excluded from Cohort 2. Efforts will be made to potentially locate patients through either the original CHAMPS investigative sites, through the Biogen Idec patient services database, and/or a third party (i.e., patient location service vendor) or some combination of the three. .

For both cohorts, public databases may be utilized for patient reported death.