SELECT

Treatment tested

• Daclizumab

  Interleukin-2 receptor inhibitor

Placebo or sham

• Placebo

Other measures (4)

Key Inclusion Criteria: * Multiple Sclerosis (MS) subjects who have a confirmed diagnosis of relapsing-remitting MS according to McDonald criteria #1-4 and a baseline Expanded Disability Status Scale (EDSS) between 0.0 and 5.0, inclusive, who meet either of the following 2 criteria: * Have experienced at least 1 relapse within the 12 months prior to randomization, with a cranial magnetic resonance imaging (MRI) demonstrating lesion(s) consistent with MS , OR * Show evidence of gadolinium-enhancing lesions of the brain on an MRI performed within the 6 weeks prior to randomization. Key Exclusion Criteria: * Diagnosis of primary progressive, secondary progressive, or progressive relapsing MS * History of malignancy * History of severe allergic or anaphylactic reactions or known drug hypersensitivity * History of abnormal laboratory results based on investigator judgment * History of human immunodeficiency virus (HIV) or other immunodeficient conditions * History of drug or alcohol abuse within the 2 years prior to randomization * An MS relapse that has occurred within the 50 days prior to randomization AND/OR the subject has not stabilized from a previous relapse prior to randomization * Positive screening for active infection with Hepatitis B virus or Hepatitis C virus * Varicella or herpes zoster virus infection or any severe viral infection within 6 weeks before Screening * Exposure to varicella zoster virus within 21 days before Screening. * Abnormal blood tests at Screening: Hemoglobin ≤9.0 g/dL, Platelets ≤100 × 10\^9/L, Lymphocytes ≤1.0 × 10\^9/L, Neutrophils ≤1.5 × 10\^9/L, alanine aminotransferase/serum glutamate pyruvate transaminase (ALT/SGPT), aspartate aminotransferase/serum glutamic oxaloacetic transaminase (AST/SGOT), or gamma-glutamyl-transferase >2 times the upper limit of normal (ULN) and serum creatinine >ULN. NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

The primary objective of this study is to determine whether DAC HYP, when compared to placebo, is effective in reducing the rate of relapses between baseline and Week 52. The secondary objectives are to determine whether DAC HYP is effective in reducing the number of new gadolinium (Gd)-enhancing lesions, reducing the number of new or newly-enlarging T2 hyperintense lesions, reducing the proportion of participants with relapses, and improving quality of life.