Palbociclib plus letrozole versus placebo plus letrozole in Asian postmenopausal women with oestrogen receptor–positive/human epidermal growth factor receptor 2–negative advanced breast cancer: Primary results from PALOMA-4

BACKGROUND: The cyclin-dependent kinase 4/6 inhibitor palbociclib has demonstrated efficacy and a manageable safety profile in combination with endocrine therapy in women with oestrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) in international phase 3 trials. The phase 3 PALOMA-4 trial evaluated the efficacy and safety of palbociclib plus letrozole versus placebo plus …