The initial BG00012 dosage for the extension study (240 mg BID or 240 mg TID) was the same as that used in the Phase 3 Studies 109MS301 (NCT00420212) and 109MS302 (NCT00451451). Subsequent to the initiation of this study, BG00012 was approved in several countries for the treatment of MS at a dose of 240 mg BID. For this reason, all participants continuing in this study will receive the currently marketed dose of 240 mg BID.