Dr. Edith Perez on BOLERO-1 Results in HER2-Positive Breast Cancer

Edith Perez, MD, the deputy director at large for the Mayo Clinic Cancer Center, compares the results of the BOLERO-1 and BOLERO-3 trials.

The BOLERO-1 trial randomized 719 patients with locally advanced or metastatic HER2-positive breast cancer in a 2:1 ratio to either everolimus with paclitaxel and trastuzumab, or placebo plus paclitaxel and trastuzumab. Perez says the results of this trial were disappointing because the addition of everolimus to chemotherapy did not improve outcomes for patients eligible to receive first-line therapy.

However, results from the BOLERO-3 trial had a different outcome. The BOLERO-3 trial analyzed patients with HER2-positive, trastuzumab-resistant, advanced breast cancer treated with daily everolimus plus weekly trastuzumab and vinorelbine, to placebo plus trastuzumab plus vinorelbine. In this trial, everolimus improved progression-free survival (PFS).

Perez advises that everolimus does have significant toxicities. Now that there is data showing positive results with trastuzumab plus pertuzumab in overall survival (OS) and PFS in the frontline setting, she predicts it would be difficult for everolimus to develop a similar role.