A Study to Investigate the Safety, Tolerability and Pharmacokinetics of Multiple Doses of MT-8554 in Female Subjects Experiencing Vasomotor Symptoms

Inclusion Criteria: * Subjects must meet one of the following criteria:Woman aged ≥18 years with histologically proven non-metastatic breast cancer (Stages I, II or III) and without evidence of disease / Woman aged ≥40 years who are post-menopausal / Woman aged ≥40 years who are peri-menopausal * Subjects who have ≥7 Vasomotor Symptoms per day on average * A body weight of ≥45 kg Exclusion Criteria: * Participation in more than three clinical studies involving administration of an unlicensed Investigational Medicinal Product in the previous year, or any study within 12 weeks * Clinically significant endocrine, thyroid, hepatic, respiratory, gastro-intestinal, renal, cardiovascular disease, or history of any significant psychiatric/psychotic illness disorder * Clinically relevant abnormal medical history, physical findings or laboratory values