deaths (OS)progression or deaths (PFS)RFS/DFS

la/mBC - HR-positive - 1st line (L1) breast cancer - HR positive la/mBC - HR positive la/mBC - HR-positive - 1st line (L1)

versus letrozole
lapatinib plus letrozole vs. letrozole 2 - certainty unassessablestatistically conclusive-13%-

la/mBC - HR positive - L1 - PIK3CA mutant breast cancer - HR positive la/mBC - HR positive la/mBC - HR-positive - 1st line (L1) la/mBC - HR positive - L1 - PIK3CA mutant