Palbociclib with trastuzumab with or without pertuzumab and endocrine therapy for HR+/HER2+ metastatic breast cancer

Palbociclib in combination with trastuzumab with or without pertuzumab and endocrine therapy is currently in clinical development for use as a maintenance therapy for patients with hormone receptor positive (HR+) and human epidermal growth factor receptor 2 positive (HER2+) metastatic breast cancer who have had prior treatment. Breast cancer occurs when abnormal cells in the breast begin to grow and uncontrollably divide, and eventually form a growth (tumour). Metastatic breast cancer is cancer that has spread beyond the breast to other parts of the body, and usually cannot be treated with surgery. HR+/HER+ breast cancer is a particularly aggressive subtype of breast cancer. Affected patients often experience disease progression after standard treatment.