Hideko Yamauchi^1,2, Tiffany LaFortune^3,4 and Naoto T. Ueno^3,4

¹Department of Breast Surgical Oncology, St. Luke’s International Hospital, Tokyo, Japan. ²Department of Oncology, Moffitt Cancer Center, Tampa, Florida. ³Departments of Breast Medical Oncology, ⁴Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, U.S.A.

Abstract

Lapatinib is an oral dual tyrosine kinase inhibitor against epidermal growth factor receptor (EGFR) and HER-2/neu (HER2). The success of trastuzumab in breast cancer prompted investigations of lapatinib in breast cancer, which revealed that lapatinib has effectiveness similar to that of trastuzumab. Clinical trials showed that lapatinib is effective for patients with HER2-positive breast cancer. Furthermore, lapatinib may be effective in patients with central nervous system metastasis that developed after trastuzumab therapy. Lapatinib may have synergistic effects with trastuzumab or hormonal therapy. There are encouraging preliminary data on the efficacy of lapatinib in patients with inflammatory breast cancer. Ongoing trials may give us exciting data on lapatinib as adjuvant therapy. HER2 positivity is a strong predictor of response to lapatinib, but the predictive value of EGFR positivity is less clear. While cardiac toxic effects have been observed with lapatinib, their incidence and severity are less significant than with trastuzumab. Current data indicate that lapatinib is a promising agent with unique potential benefits in the treatment of metastatic breast cancer.