Research summary
June 2006
Research shows experimental drug lapatinib (Tykerb®) slows the spread of HER-2 positive breast cancer in women with advanced disease
Summary
Clinical trial results have shown the experimental drug lapatinib (Tykerb®) slows the spread of advanced breast cancer when used in combination with chemotherapy.
The results of the international trial involving 392 women with advanced breast cancer, including some Australian women, were presented at the American Society for Clinical Oncology (ASCO) Annual Meeting in Atlanta. All the women involved in the trial had previously been treated with Herceptin® to slow the spread of HER-2 positive breast cancer but Herceptin® had stopped working for them.
The trial showed that when given in combination with chemotherapy, lapatinib slows the development of the cancer, nearly doubling the length of time patients live without the disease before it progressed to other parts of their body.
The lapatinib was taken daily as a pill. It works by blocking two receptors, which are associated with tumour growth and the spread of cancer. Herceptin® only blocks one of these receptors.
The researchers stopped the trial early because of the significant results. Further details of the results and any side effects are not yet available as there is no published data from the trial at this time.
National Breast Cancer Centre comment
The National Breast Cancer Centre welcomes this new research into targeted therapies to improve outcomes for women with advanced (metastatic) breast cancer. Such therapies improve not only life expectancy but also quality of life for women with breast cancer. These are important results as they provide hope for an improved outlook for women with advanced breast cancer.
The trial results for lapatinib apply only to women with HER-2 positive advanced breast cancer. ‘HER-2 positive’ means these women have a particular protein called ‘HER-2’ on their cancer cells. Approximately 20 to 25 per cent of women diagnosed with breast cancer each year have HER-2 positive breast cancer – a more aggressive form of the disease.
Advanced or metastatic breast cancer means the cancer cells have spread from the breast to other areas of the body, such as the bones or the lungs. About 15 per cent of women with breast cancer in Australia have advanced or metastatic disease at diagnosis.
Herceptin® is a targeted breast cancer therapy currently approved for use in Australia in the treatment of women with advanced breast cancer who are HER-2 positive.
Early trial results indicate lapatinib may be an alternative treatment option for women with advanced HER-2 positive breast cancer, for whom Herceptin® is not effective. However, while lapatinib has been shown to slow the spread of cancer it does not stop the spread of the disease.
Lapatinib has not yet been submitted to Australian regulatory authorities for approval for use. It is only available in Australia through clinical trials at this stage. For more information about involvement in clinical trials, talk to your medical oncologist.
While these early results are encouraging, the National Breast Cancer Centre will await the full trial data, including safety data, and the results of further trials.