 The purpose of this study is to determine if high-dose cyclophosphamide followed by a maintenance dose of glatiramer acetate is safe in patients with relapsing remitting multiple sclerosis MS. The investigators hypothesize that institution of glatiramer acetate treatment following high-dose cyclophosphamide treatment will extend the period of disease free activity and further reduce the disability in patients with relapsing remitting multiple sclerosis. The investigators plan to investigate the properties of glatiramer acetate against the recurrence of MS disease activity following high dose cyclophosphamide induced cessation detectable autoimmunity. The investigators hypothesize that glatiramer acetate, given in the phase of immune reconstitution after high-dose cyclophosphamide, may bias the immune system to a more tolerated state, thus leading to more stable and potentially permanent remissions. 