ERBB2 and breast cancer: On September 28, 2017, abemaciclib was approved in combination with fulvestrant for women with HR+/HER2-ABC/MBC with disease progression following endocrine therapy based on the MONARCH 2 trial, which was a randomized, multicenter, double-blind, placebo-controlled phase III trial (https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-abemaciclib-hr-positive-her2-negative-breast-cancer).