Lapatinib plus capecitabine is superior to capecitabine alone in women with HER2-positive advanced breast cancer that has progressed after treatment with regimens that included an anthracycline, a taxane, and trastuzumab. (ClinicalTrials.gov number, NCT00078572 [ClinicalTrials.gov].).

This trial demonstrated that a combined targeted strategy with letrozole and lapatinib significantly enhances PFS and clinical benefit rates in patients with MBC that coexpresses HR and HER2.

The addition of lapatinib to capecitabine provides superior efficacy for women with HER2-positive, advanced breast cancer progressing after treatment with anthracycline-, taxane-, and trastuzumab-based therapy. Biomarker studies could not identify a subgroup of patients who failed to benefit from the addition of lapatinib to capecitabine.

Lapatinib demonstrated clinical activity and was well tolerated as first-line therapy in ErbB2-amplified locally advanced or metastatic breast cancer. This study supports further evaluation of lapatinib in first-line and early-stage ErbB2-overexpressing breast cancer.