A Phase 1 Study of AZD9833 in Japanese Women With ER Positive, HER2 Negative Advanced Breast Cancer

Objectives: Primary objective: To investigate the safety and tolerability of AZD9833 in Japanese women with ER+ HER2- advanced breast cancer Secondary objective: To assess the anti-tumor activity and efficacy of AZD9833 Exploratory objectives: To investigate AZD9833 activity in tumor cells Overall design: This is a Phase 1, open-label study designed to evaluate the safety, tolerability, pharmacokinetics, and anti-tumor activity of AZD9833 in Japanese women with endocrineresistant ER+ HER2- breast cancer that is not amenable to treatment with curative intent. Eligible patients will receive AZD9833. In cohort 1 (for tolerability evaluation), a minimum of 3 to maximum 6 evaluable patients will be enrolled. For cohort 2, if paired biopsy after administration of the study drug becomes inoperable during administration of the study drug, additional subjects can be added to obtain an evaluable biopsy sample. In cohort 2 (for exploratory research), eligible patients will receive AZD9833 once daily and at least 6 to maximum 12 patients will be enrolled. In cohort 2, paired biopsy sample will be collected from at least 6 and maximum 12 patients. If paired biopsy after administration of the study drug becomes inoperable during administration of the study drug, additional subjects can be added to obtain an evaluable biopsy sample. Number of Subjects: Maximum 18 evaluable subjects will be enrolled in this study.