Most patients had had a median of three previous cancer therapy regimens (range: 1.00, 7.00) prior to alpelisib, which included prior cytotoxic therapy (eribulin, taxane, capecitabine, gemcitabine, platinum, anthracycline), targeted agents (CDK4/6 inhibitors, everolimus, olaparib), and hormonal agents (AI, selective estrogen receptor degrader or down-regulator (SERD) (Table 2). Here, ESR1 is linked to cancer.