Dr. Tolaney on Remaining Questions With CDK4/6 Inhibitors in HR+/HER2- Breast Cancer

Sara M. Tolaney, MD, MPH, associate director of the Susan F. Smith Center for Women’s Cancers; director of Clinical Trials, Breast Oncology; senior physician at Dana-Farber Cancer Institute, and assistant professor of medicine at Harvard Medical School, discusses remaining questions with CDK4/6 inhibitors in hormone receptor (HR)—positive, HER2-negative metastatic breast cancer.

One major questions with CDK4/6 inhibitors that has arisen is whether there are major differences in outcomes between patients who receive chemotherapy compared with those who receive endocrine therapy plus CDK4/6 inhibition. Some data from the Young-PEARL trial were presented at the 2019 ASCO Annual Meeting and offered some insight, says Tolaney.

In the phase 2 trial, investigators enrolled premenopausal patients with HR-positive, HER2-negative metastatic breast cancer who progressed on prior tamoxifen. These patients were randomized to receive either aromatase inhibition and palbociclib (Ibrance) or capecitabine. At a median follow-up of 14 months, the median progression-free survival was 19.0 months in the endocrine with palbociclib arm versus 11.3 months in the capecitabine arm. The trial demonstrated that CDK4/6 inhibition is a very effective approach for this patient population and is likely superior to chemotherapy, concludes Tolaney.