The FDA granted accelerated approval for the use of lapatinib (Tykerb) with letrozole(Drug information on letrozole) (Femara) as a first-line, oral treatment for women with metastatic disease. The combination is now indicated for postmenopausal women with HR-positive breast cancer that overexpresses the HER2 receptor. .
In the U.S. and Europe, between 60% and 70% of all breast cancers are HR-positive and between 25% and 30% overexpress HER2, according to GlaxoSmithKline, the manufacturer of Tykerb. Approval was based on results from a placebo-controlled study of 219 women. Those treated with lapatinib and letrozole experienced a 5.2-month increase in progression-free survival vs treatment with letrozole alone. Adverse reactions included diarrhea, rash, and nausea.