GlaxoSmithKline (GSK) announced the submission of two simultaneous regulatory applications to expand the use of Tyverb/Tykerb (lapatinib). If authorised, lapatinib could be used as a first-line therapy regimen combined with anti-hormonal therapy for patients with hormone-sensitive, metastatic (or advanced) breast cancer in Europe and the United States.

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. Approximately 70 per cent of all breast cancer cases are HR+.

"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."

Lapatinib is an oral small-molecule inhibitor of the HER2/ErbB2 tyrosine kinase receptor.