Safety and Efficacy Extension Study of Daclizumab High Yield Process (DAC HYP) (BIIB019) in Participants Who Have Completed Study 205MS202 (NCT00870740) to Treat Relapsing Remitting Multiple Sclerosis

This study will provide participants who complete Study 205MS202 (NCT00870740) with the option to receive continued open-label Daclizumab High Yield Process (DAC HYP) monotherapy and to evaluate the long-term safety, efficacy, and immunogenicity of DAC HYP monotherapy in participants with relapsing remitting multiple sclerosis (RRMS). Approximately 60 to 100 participants will be enrolled into an optional open-label, 16-week autoinjector substudy at a selected subset of sites which will run concurrently during the main study, and will evaluate the systemic exposure and local tolerability of subcutaneous administration of DAC HYP by autoinjector. The 2013-2014 trivalent influenza vaccine will be offered to all eligible participants as an optional substudy to assess the effect of DAC-HYP treatment on the immune response to vaccination,