In this study, 45 patients with locally advanced ErbB2 over-expressing breast cancer, received lapatinib before surgery, initially as a single agent for the first six weeks, followed by a combination of lapatinib plus weekly trastuzumab and three-weekly docetaxel for 12 weeks. Biopsies were taken at time of diagnosis and after six weeks of lapatinib, and assessed for tumourigenic cells.
Results showed significant tumor regression (median decrease of -60.8%, p=0.001) in primary tumors after only six weeks of single agent lapatinib. Unlike treatment with chemotherapy, lapatinib decreased tumorigenic breast cancer stem cells from 10.6% to 4.7%. The pathologic complete response rate following combination treatment (lapatinib plus trastuzumab and docetaxel) was 63%.
Steven Stein, vice president, Oncology Medicine Development Centre, GlaxoSmithKline, said: “For example, stem cell research may bring us closer towards understanding why, in some women, breast cancer can return after lying dormant for many years following full remission. We are encouraged by the data from this study and are committed to further investigations.”