LAPATINIB IN BREAST CANCER – THE PREDICTIVE SIGNIFICANCE OF HER1 (EGFR), HER2, PTEN AND PIK3CA GENES AND LAPATINIB PLASMA LEVEL ASSESSMENT

therapy/Biological therapy/Metastatic breast cancer/Lapatinib plasma level Background. Breast cancer treatment trends are currently based on tailored therapies using tumor and patient biomarkers. Lapatinib is the first dual inhibitor of HER1 (EGFR, ErbB1) and HER2 (ErbB2, Neu) tyrosine kinases to be used in clinical practice. However, only HER2 is currently used for therapy indications and new predictors for the treatment with lapatinib are sought. Methods and results. This minireview focuses on lapatinib and its role in breast cancer treatment. Preclinical and clinical studies as well as pharmacological characteristics are briefly reviewed while the focus is on efficacy assessment including predictive factors for therapy outcome. Conclusion. Lapatinib (Tykerb/Tyverb) was Food and Drug Administration (FDA) approved in 2007 for use in combination with capecitabine for the treatment of HER2-positive advanced or metastatic breast cancer in patients who had received previous treatment (including anthracycline, taxane and trastuzumab containing regimens) and in 2010 for use in combination with letrozole for postmenopausal women with hormonal receptor positive and HER2-positive metastatic breast cancer. In contrast to trastuzumab (Herceptin), lapatinib is orally administered and it target