Efficacy and Safety Study of MCI-186 for Treatment of Amyotrophic Lateral Sclerosis (ALS)

Inclusion Criteria: * Patients who are defined as "definite ALS," "probable ALS" or "probable-laboratory-supported ALS," met diagnostic criteria revised EL Escorial for Airlie House. * Patients who can eat a meal, excrete, or move with oneself alone, and do not need assistance in everyday life. * Patients of less than 3 years after the onset of ALS. * Patients whose progress of the condition during 12 weeks before administration meet other requirements. Exclusion Criteria: * Patients judged to be inadequate to participate in this study by their physician, because those patients' general condition deteriorated to the point that they need to be hospitalized for severe hepatic disease, severe heart disease, severe renal disease and so on, or they need to be administered antibiotics to infection. * Patients who complain the difficulty in breathing caused by deteriorating the respiratory function. * Patients with such complications as Parkinson's disease, schizophrenia, dementia, renal failure, or other severe complication, and patients who have the anamnesis of hypersensitivity to edaravone. * Pregnant, lactating, and probably pregnant patients, and patients who want to become pregnant, and patients who can not agree to contraception. * Patients who have participated in other trials within 12 weeks before consent, or who are participating in other clinical trials at present. * In addition to the above exclusion criteria, patients judged to be inadequate to participate in this study by their physician.