Combination of Palbociclib and Endocrine Therapy in Hormone Receptor-Positive and Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer With or Without Brain Metastases.

Palbociclib plus endocrine therapy in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer was effective and well-tolerated, even in patients with brain metastases. More benefits were observed in frontline therapy, chemotherapy-naive, and endocrine therapy-sensitive patients with fewer metastatic sites.