everolimus + lapatinib + letrozole

This is a combination therapy consisting of three small-molecule drugs—everolimus (an mTOR inhibitor), lapatinib (a dual tyrosine kinase inhibitor targeting HER2 and EGFR), and letrozole (an aromatase inhibitor). The regimen is under investigation for the treatment of hormone receptor-positive, HER2-positive advanced or metastatic breast cancer. Everolimus inhibits the mammalian target of rapamycin (mTOR) pathway to suppress tumor cell growth and proliferation. Lapatinib blocks both HER2/neu (ERBB2) and epidermal growth factor receptor (EGFR/ERBB1) signaling pathways to inhibit tumor cell proliferation. Letrozole reduces estrogen production by inhibiting aromatase, thereby limiting hormone-driven cancer cell growth. This triple combination aims to overcome resistance mechanisms in heavily pretreated breast cancers by simultaneously targeting multiple oncogenic pathways[1][3][8].