The primary objective of the study was to evaluate the immunogenicity of Avonex® (interferon beta-1a) 30 mcg when administered subcutaneously (SC) to interferon-naïve participants with relapsing multiple sclerosis. The secondary objective of this study was to evaluate the safety and tolerability of Avonex® 30 mcg when administered SC to interferon-naïve subjects with relapsing MS.