Delays Progression of Metastatic Breast Cancer

Each year, more than 180,000 U.S. women are diagnosed with breast cancer. Many of these breast cancers will be hormone receptor-positive, meaning that they are stimulated to grow by the circulating female hormones estrogen and/or progesterone.

Treatment of hormone receptor-positive breast cancer often involves hormonal therapies that suppress or block the action of estrogen. These therapies include tamoxifen as well as agents known as aromatase inhibitors. Tamoxifen acts by blocking estrogen receptors, whereas aromatase inhibitors suppress the production of estrogen in postmenopausal women.
Tykerb is a drug that targets two related proteins that often function abnormally in breast cancer cells—HER2 and EGFR. Approximately 20-25% of breast cancers overexpress the HER2 protein; these cancers are referred to as HER2-positive.

Femara is an aromatase inhibitor that has been shown to improve outcomes among postmenopausal women with hormone receptor-positive or hormone receptor-unknown breast cancer.

To evaluate the combination of Tykerb and Femara in the initial treatment of hormone receptor-positive, metastatic breast cancer, researchers conducted a Phase III clinical trial among 1,286 postmenopausal women. A total of 219 of the study participants were HER2-positive.

In the subset of women who were HER2-positive, progression-free survival was 8.2 months among women treated with Femara plus Tykerb compared with 3.0 months among women treated with Femara alone.Among all patients (regardless of HER status), progression-free survival was 11.9 months among women treated with Femara plus Tykerb compared with 10.8 months among patients treated with Femara alone.This study suggests that compared with treatment with Femara alone, the combination of Tykerb and Femara delays cancer progression among women with HER2-positive, hormone receptor-positive, metastatic breast cancer.