ERBB2 and breast carcinoma: This approval is based on findings from the MONALEESA-2 study, a double-blind, placebo-controlled, randomized phase 3 trial (NCT01958021) in which first-line therapy with ribociclib + letrozole significantly improved progression-free survival (PFS) compared with placebo + letrozole in patients with HR+/HER2− advanced breast cancer.