Landmark Lapatinib Data Published

Aphase III study reporting that lapatinib (Tykerb) plus capecitabine (Xeloda) is superior to capecitabine alone in women with HER2-positive advanced breast cancer who had progressed following prior therapy, including trastuzumab (Herceptin), was published recently in the New England Journal of Medicine (355:2733-2743, 2006). The study authors concluded that given its distinct mechanism of action and activity as a small-molecule dual-receptor tyrosine kinase inhibitor, lapatinib should be investigated for use in the earlier treatment of HER2-positive breast cancer. Lapatinib is an investigational medicinal product and has not been approved for marketing by any regulatory body.

"Patients with advanced or metastatic HER2-positive breast cancer have limited options once their cancer has progressed on trastuzumab and standard initial chemotherapy regimens," said lead investigator Charles Geyer, MD, director of breast medical oncology at Allegheny General Hospital, Pittsburgh. "There has been a clear need for alternative treatments to help women with metastatic breast cancer in this advanced setting. Lapatinib combined with capecitabine has demonstrated superior efficacy over capecitabine alone in this group of patients, and we look forward to it being made available to women suffering from this devastating disease."

Adverse Events

Study results demonstrate combination treatment with lapatinib was not associated with an increase in either serious toxicity or rates of discontinuation related to adverse events, compared to capecitabine treatment alone. The most common adverse events were diarrhea, hand-foot syndrome, and rash distinct from hand-foot syndrome.

Metastatic breast cancer is the leading cause of cancer deaths in women globally, resulting in more than 400,000 deaths each year. Women with HER2-positive breast cancer are at a greater risk of disease progression and death compared to women with tumors that do not overexpress HER2. Metastatic breast cancer eventually develops resistance to trastuzumab.