Induction of remission in a patient with metastatic breast cancer refractory to trastuzumab and chemotherapy following treatment with gefitinib ('Iressa', ZD1839).

Despite new therapies and several treatment options, metastatic breast cancer (MBC) remains incurable. One reason for the low median survival rate may be intense cross-talk between growth factor receptors such as the epidermal growth factor receptor (EGFR/HER1) and the HER2 growth factor receptor. This report describes the case history of a patient with MBC whose disease had progressed despite surgery, radiotherapy and four different chemotherapy regimens, including trastuzumab (a monoclonal antibody that specifically blocks HER2) combined with docetaxel. However, treatment with 500 mg/day gefitinib ('Iressa', ZD1839), an EGFR tyrosine kinase inhibitor, and trastuzumab (2 mg/kg/week) caused a rapid and sustained regression of breast cancer metastases in skin and lymph nodes. Thus, for patients with MBC whose tumors co-express EGFR and HER2, gefitinib in combination with trastuzumab may prevent receptor cross-talk, improving the outcome of MBC.