GlaxoSmithKline (GSK) announced today that the European Medicines Agency (EMA) has granted oral breast cancer treatment Tyverb (lapatinib) a new therapeutic indication. Lapatinib, in combination with an aromatase inhibitor (AI), is now indicated for the treatment of post-menopausal women with hormone receptor (HR)-positive, ErbB2 (HER2) over-expressing metastatic breast cancer and for whom chemotherapy is currently not intended. The patients in the registration study were not previously treated with Herceptin (trastuzumab) or an AI.
Professor of Breast Cancer Medicine, Stephen Johnston, Royal Marsden NHS Foundation Trust & Institute of Cancer Research commented: “Lapatinib plus an AI offers an effective, chemotherapy-free and well-tolerated option for patients with a distinct disease profile. As a first line option for these patients it offers a choice to delay the need for more aggressive and toxic therapies, such as chemotherapy. Importantly as an all-oral treatment option it allows patients to take their medication at home, relieving precious hospital resources.”
Approximately 50% of patients with ErbB2-positive metastatic breast cancer are also HR-positive. This new licensed combination allows clinicians to tailor their approach to treatment, targeting both HR and ErbB2 receptors. The results from the registration trial, EGF30008, showed that there was a significant improvement in progression-free survival (PFS) in patients that over expressed ErbB2 when both ErbB2 and HR receptors were targeted with lapatinib plus Femara (letrozole) (an AI). The randomised phase III trial, involving over 1200 post-menopausal women with HR-positive metastatic breast cancer, demonstrated that ErbB2-positive patients given lapatinib plus letrozole experienced a median 8.2 months of PFS compared with 3 months for those in the letrozole plus placebo group.
The side effects observed in the EGF30008 trial with lapatinib plus letrozole were principally diarrhoea and rash, which were generally grade 1 or 2 in severity and were manageable. Nausea and vomiting also commonly occurred as well as loss of appetite and fatigue. The safety profile of lapatinib was consistent with previously reported results from trials of lapatinib in the metastatic breast cancer population.
Lapatinib is already indicated (in combination with Xeloda [capecitebine]) for patients with ErbB2-positive metastatic breast cancer, pretreated with anthracyclines and taxanes, who have progressed following treatment with trastuzumab in the metastatic setting. However, on the 10th June 2010 NICE ruled against NHS funding for lapatinib in this indication, denying access to 2000 women who would potentially be eligible for treatment.