letrozole + pertuzumab + trastuzumab

This is a combination regimen consisting of letrozole, pertuzumab, and trastuzumab. Letrozole is an aromatase inhibitor that suppresses estrogen production, while pertuzumab and trastuzumab are monoclonal antibodies targeting the human epidermal growth factor receptor 2 (HER2). This combination targets both the HER2 pathway and estrogen receptor signaling in hormone receptor–positive, HER2-positive breast cancer. The regimen has been studied as a first-line treatment for metastatic or locally advanced breast cancer (M/LABC) that is both HER2-positive and hormone receptor–positive. Clinical trials such as PERTAIN have shown that adding pertuzumab to trastuzumab plus an aromatase inhibitor (letrozole or anastrozole) significantly improves progression-free survival compared to trastuzumab plus AI alone[1][6]. The approach leverages dual blockade of HER2 along with endocrine therapy to overcome resistance mechanisms between these pathways.

Brand names

PerjetaHerceptinFemara

Other names

Pertuzumab-trastuzumab plus letrozole