Does Adding a Targeted Agent Improve Neoadjuvant Endocrine Therapy for Breast Cancer?

For clinical response, palbociclib plus letrozole was not superior to endocrine therapy alone.

Neoadjuvant endocrine therapy for breast cancer is less common in the U.S. than in Europe; still, this approach might merit reconsideration, particularly as more is understood about the sensitivity of luminal cancers to chemotherapy. Furthermore, as cyclin-dependent kinase 4/6 (CDK4/6) inhibitors such as palbociclib have been shown to enhance the activity of aromatase inhibitors and fulvestrant in advanced disease, preoperative partnering of these targeted agents with endocrine therapy is attractive. In the phase II PALLET study, investigators randomized 307 postmenopausal women with estrogen receptor–positive early breast cancer to one of four groups:

Letrozole (2.5 mg daily) for 14 weeks
Letrozole for 2 weeks followed by palbociclib (125 mg…

Reviewing Author

William J. Gradishar, MD

Disclosures

Consultant/Advisory BoardLilly; AstraZeneca; Gilead

Grant/Research SupportBreast Cancer Research Foundation

Editorial BoardsClinical Breast Cancer; Oncology; Annals of Surgery; Breast Cancer Research and Treatment

Leadership Positions in Professional SocietiesNational Comprehensive Cancer Network (Chair, Breast Cancer Panel); American Board of Internal Medicine (Medical Oncology Board)