Therapy with Lapatinib: Current Status in Women with Advanced Breast Cancer

HER-2 overexpression occurs in 20-30% of women with breast cancer and is associated with poor prognosis and reduced overall survival. The small molecule lapatinib is an orally administered dual receptor tyrosine kinase inhibitor of HER-1 and HER-2. Preclinical in vitro and in vivo models as well as early clinical trials provided evidence that lapatinib is active against breast cancer. Women with advanced or metastatic HER-2-positive breast cancer have limited therapeutic options once their disease has progressed on trastuzumab and standard initial chemotherapy regimens. There has been a clear need for alternative treatments in this advanced setting. In a recently published phase III trial, lapatinib combined with capecitabine has demonstrated superior efficacy over capecitabine alone in this group of patients, with a median time to tumor progression of 8.4 months in the combination therapy group versus 4.4 months in the monotherapy arm. This improvement was achieved without an increase in serious toxic effects or symptomatic cardiac events.