Once‐daily glatiramer acetate decreases magnetic resonance imaging disease activity in Japanese patients with relapsing–remitting multiple sclerosis

Objective Multiple sclerosis (MS) prevalence, clinical patterns, and treatment responses vary between races and geographical latitudes. Glatiramer acetate (GA; Copaxone) has provided a safe, effective treatment option for relapsing–remitting MS patients in the USA, European nations, and other countries for decades. The objective of the present study was to assess the safety and efficacy of GA in reducing magnetic resonance imaging disease activity in Japanese patients with active relapsing–remitting MS. Methods This phase 2, multicenter, open‐label, single‐arm, 52‐week study measured the effect of GA 20 mg once‐daily on magnetic resonance imaging disease activity. GA efficacy was evaluated through week 36, and safety through week 52. The primary end‐point was change in the mean number of T1‐weighted gadolinium‐enhancing (GdE) lesions from pretreatment (weeks –8, –4 and baseline) to weeks 28, 32 and 36. Secondary end‐points included a change in mean number of new T2‐weighted lesions, GdE lesion and T2 lesion volumes, annualized relapse rate, and Expanded Disability Status Scale scores. Results GA therapy reduced the number of new GdE lesions by 65.66% (95% CI 33.19–82.35%). The number of new T2 lesions and GdE lesion volume were also reduced from pretreatment. The annualized relapse rate was reduced by 42% compared with the 1 year before treatment. Changes in T2 lesion volume and Expanded Disability Status Scale scores were favorable, but less pronounced. Most common adverse events were injection‐site reactions. Conclusions The present study confirmed the well‐established safety, tolerability and efficacy profile of GA in Japanese MS patients. This phase 2, multi‐center, open‐label, 52‐week study confirmed the well‐established GA safety, tolerability and efficacy profile in Japanese MS patients. Patients experienced a 65% reduction in Gd‐enhancing MRI lesions and a 42% reduction in annualized relapse rate from pre‐treatment levels.