Dr. Baselga Discusses the BOLERO Breast Cancer Trials

José Baselga, MD, PhD, a professor in the Department of Medicine at Harvard Medical School and chief of Hematology/Oncology at Massachusetts General Hospital, describes the 3 phase III BOLERO trials investigating everolimus (Afinitor), a mammalian target of rapamycin inhibitor, in various stages of breast cancer.

• BOLERO-1 is still recruiting patients; it seeks to add first-line everolimus to trastuzumab (Herceptin) and paclitaxel in women with HER2-positive locally advanced or metastatic breast cancer.
• BOLERO-2 demonstrated the efficacy of adding everolimus to exemestane in women with aromatase inhibitor resistant, hormone receptor-positive, metastatic breast cancer. It successfully extended the time to disease progression by 4.2 months (HR, 0.44).
• BOLERO-3, which is still recruiting patients, will combine everolimus with trastuzumab and vinorelbine for post-menopausal HER2-positive breast cancer that is resistant to trastuzumab.

If the results from the BOLERO-1 and 3 trials are as positive as BOLERO-2 they will demonstrate the efficacy of everolimus in HER2-positive breast cancer, in both the first-line and refractory setting. BOLERO-2 was a second-line trial; Baselga feels a follow up study should include the first-line and adjuvant setting.

The findings of the BOLERO-2 trial go far beyond the patient population in the study. This research opens up the entire field of mTOR/PI3K-targeted therapies in multiple tumor types.