The variation to the EU marketing authorisation and the supplemental New Drug Application (sNDA) were submitted respectively to the European Medicines Agency (EMEA) and to the U.S. Food and Drug Administration (FDA) for the combination of lapatinibplus an aromatase inhibitor based on the recent study, EGF30008. This study evaluated lapatinib in combination with letrozole in women with hormone receptor positive (HR+) metastatic breast cancer that may or may not also overexpress the HER2+/ErbB2+ receptor.

These data were presented at the San Antonio Breast Cancer Symposium in December 2008.

Breast cancer tumours which initially respond to anti-hormonal therapy such as letrozole can become resistant to treatment, leading to disease progression and ultimately, patient death.[1] Approximately 70 percent of all breast cancer cases are HR+[2].

"Lapatinib with a hormone therapy is a biologically-rational targeted treatment, since the combination attacks two specific receptors that drive the cancer growth," said Debasish Roychowdhury, MD, Head, Medicines Development, GSK Oncology. "If authorised, the combination could provide a cytotoxic chemotherapy-free option for these patients and we look forward to working with regulatory agencies to advance the availability of this regimen as a new, oral option for patients in first-line breast cancer."

About Tyverb/Tykerb(lapatinib)
Lapatinib is an oral small-molecule inhibitor of the HER2/ErbB2 tyrosine kinase receptor. Stimulation of HER2/ErbB2 is associated with cell proliferation and with multiple processes involved in tumour progression and metastases. Overexpression of these receptors has been reported in a variety of human tumours and is associated with poor prognosis and reduced overall survival.

Lapatinib, in combination with capecitabine, is authorised in 74 countries. On March 13, 2007, the U.S. FDA approved lapatinib in combination with capecitabine for the treatment of patients with advanced or metastatic breast cancer whose tumours overexpress HER2/ErbB2 and who have received prior therapy including an anthracycline, a taxane, and trastuzumab. On June 10, 2008, the European Commission granted a conditional marketing authorisation for lapatinib in all 27 European Union (EU) member states. Other countries in which lapatinib is authorised for marketing include Australia, India, Brazil, Russia, Switzerland, Turkey, South Korea, Taiwan and others around the world. Registration dossiers for lapatinib have been filed in Canada, China, Japan, Mexico and a number of countries in Latin America, Middle East, Africa and Asia Pacific.

GSK in Oncology
GSK Oncology is dedicated to producing innovations in cancer that will make profound differences in the lives of patients. Through GSK's revolutionary 'bench to bedside' approach, we are transforming the way treatments are discovered and developed, resulting in one of the most robust pipelines in the oncology sector. Our worldwide research in oncology includes collaborations with more than 160 cancer centres. GSK is closing in on cancer from all sides with a new generation of patient-focused cancer treatments in prevention, supportive care, chemotherapy and targeted therapies.

GlaxoSmithKline - one of the world’s leading research-based pharmaceutical and healthcare companies - is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For further information please visit www.gsk.com.

TYKERB® is a registered trademark of the GlaxoSmithKline group of companies in the United States and the countries outside of Europe.

TYVERB® is a registered trademark of the GlaxoSmithKline group of companies in European Union.

References
[1] Prat, A and Baselga, J. The role of hormonal therapy in the management of hormonal-receptor-positive breast cancer with co-expression of HER2. Nature Clinical Practice Oncology. 2008;5:531-542
[2] Bedard PE, Freedman OC, Howell A et al. Overcoming endocrine resistance in breast cancer – are signal transduction inhibitors the answer. Breast Cancer Res Treat. 2008 108:307-317