In the double-blind, placebo-controlled, Phase 3 DEFINE study in patients with relapsing–remitting multiple sclerosis, oral BG-12 (dimethyl fumarate) significantly reduced the proportion of patients relapsed (primary endpoint), the annualized relapse rate (ARR), and confirmed disability progression (secondary endpoints) at two years compared with placebo. We investigated the efficacy of BG-12 240 mg twice daily (BID) and three times daily (TID) in patient subgroups stratified according to baseline demographic and disease characteristics including gender, age, relapse history, McDonald criteria, treatment history, expanded disability status scale score, T2 lesion volume, and gadolinium-enhancing lesions. The clinical efficacy of BG-12 was generally consistent across patient subgroups and reflected positive findings in the overall DEFINE study population. Treatment with BG-12 BID and TID reduced the proportion of patients relapsed and the ARR at two years compared with placebo in all patient subgroups. Reductions in the risk of relapse with BG-12 BID vs. placebo ranged from 68 % [hazard ratio 0.32 (95 % confidence interval (CI) 0.16–0.62)] to 26 % [0.74 (0.51–1.09)] and from 66 % [0.34 (0.23–0.50)] to 25 % [0.75 (0.42–1.36)] with BG-12 TID vs. placebo. BG-12 also reduced the risk of disability progression at two years compared with placebo in most subgroups of patients treated with the BID dosing regimen and in all subgroups treated with the TID regimen. These analyses indicate that treatment with BG-12 is consistently effective across a wide spectrum of patients with relapsing–remitting multiple sclerosis with varied demographic and disease characteristics.