['Interferon beta (IFNβ) is standard therapy for multiple sclerosis (MS). The efficacy of intramuscular (IM) IFNβ-1a (AVONEX(®)) was assessed in 25 Japanese patients with relapsing-remitting MS (RRMS).', "Patients with RRMS not previously treated with IFNβ or other disease-modifying therapies were included in this 36-week study. The primary outcome was the average total number of gadolinium-enhanced lesions detected on four brain MRI scans during the last 12 weeks of 24 weeks' treatment with IM IFNβ-1a 30 μg once weekly compared with the number during the 12-week pre-treatment period. Lesions were counted by blinded investigators.", 'IM IFNβ-1a significantly decreased the median number of gadolinium-enhanced lesions from 2.5 to 0.3 (p < 0.0001) compared with pre-treatment values. The median number of new gadolinium-enhanced lesions also decreased significantly from 2.0 to 0.3 (p = 0.0002). Serum neopterin was induced in a manner similar to that observed previously in a Caucasian RRMS population. No new adverse events occurred during the study.'] Is intramuscular interferon beta-1a effective in Japanese patients with relapsing-remitting multiple sclerosis : a pre-treatment versus treatment comparison study of gadolinium-enhanced MRI brain lesions?