FDA Approves Tykerb in Conjunction with Femara as Additional Breast Cancer Treatment

On January 29, 2010, the U.S. Food and Drug Administration approved the concurrent use of the oral drugs Tykerb (lapatinib) and Femara (letrozole) in the treatment of metastatic breast cancer in postmenopausal women. The drug combination has been approved as a therapy for hormone positive and HER2-positive advanced breast cancer.

HER2 is a protein receptor that aids in cell development by transmitting signals that prompt cells to grow and multiply. In women with HER2-positive breast cancer, cancer cells overexpress this receptor, resulting in a disease that is particularly aggressive and subject to quick progression. Approximately one in every four women with breast cancer has tumors that contain cells with an unusually high number of HER2 genes.

Tykerb works by inhibiting the HER2 receptor, while Femara inhibits the growth effects of estrogen on cancer cells. In clinical trials, women with HER2-positive breast cancer who took Tykerb in combination with Femara lived 35 weeks without a progression of the disease compared to only 13 weeks in patients who received Femara alone.

Tykerb was originally approved to treat advanced breast cancer when used alongside a chemotherapy drug called Xeloda in 2007. This combination was only used after patients had undergone treatment with other chemotherapy medications.

The FDA’s new approval for the combined use of Tykerb and Femara represents an additional treatment option for breast cancer patients that may postpone the need for more invasive chemotherapy. The combination of Tykerb and Femara is an exclusively oral treatment and was most commonly associated with the side effects of diarrhea, fatigue, nausea and rash in clinical trials.