ERBB2 and breast cancer: However, recently the randomized RIGHT Choice phase II trial showed longer PFS (primary endpoint) with first-line ribociclib plus ET vs a chemotherapy doublet in pre- or perimenopausal patients with hormone receptor-positive HER2-negative (HER2-) advanced breast cancer with aggressive clinical features (rapidly progressing or highly symptomatic disease, including life-threatening visceral crisis) (37).