Ingrid A. Mayer, MD, co-leader and clinical director, Breast Cancer Research Program Chair, Data and Safety Monitoring Committee, associate professor of Medicine (Hematology/Oncology), medical oncologist, Vanderbilt-Ingram Cancer Center, discusses the use of targeted therapies in estrogen-receptor (ER)-positive breast cancer.

In the early setting, targeted therapies are being incorporated in both the adjuvant and neoadjuvant settings, says Mayer. There are several trials ongoing and being planned utilizing CDK4/6 inhibitors, as well as everolimus. If these trials end up showing a survival advantage, it would revolutionize the way patients with ER-positive breast cancer are treated, she says.

In the metastatic setting, there are also numerous targeted therapies being investigated including CDK4/6 inhibitors, PI3-kinase inhibitors, histone deacetylase inhibitors, EGFR inhibitors, and more. Patient selection is going to be one of the biggest challenges, says Mayer. Instead of large trials, studies may need to be smaller and more specific going forward.