Overall survival (OS) with first-line palbociclib plus letrozole (PAL plus LET) versus placebo plus letrozole (PBO plus LET) in women with estrogen receptor positive/human epidermal growth factor receptor 2-negative advanced breast cancer (ER+/HER2−ABC): Analyses from PALOMA-2 - Finn, RS; Rugo, HS; Dieras, VC (J Clin Oncol, 2022)