Dr. Marcom on Impact of FALCON Trial on HR+ Breast Cancer

Paul Kelly Marcom, MD, associate professor of Medicine, Duke University School of Medicine, Duke Cancer Institute, discusses the impact that the FALCON trial findings have had on the field of hormone receptor (HR)-positive breast cancer.

In the phase III FALCON trial, first-line treatment with fulvestrant (Faslodex) led to significantly better progression-free survival (PFS) versus anastrozole (Arimidex) for patients with HR-positive advanced breast cancer. Results showed that there was a median PFS of 16.6 months with fulvestrant versus 13.8 months with anastrozole. A consistent advantage favoring fulvestrant also emerged from a subgroup analysis. The overall advantage appeared to be driven by a substantial difference in PFS among patients without visceral metastases treated with fulvestrant.

What is fascinating about the FALCON trial, Marcom explains, is that it was a bold attempt to identify patients who are completely endocrine-naïve. These are patients who never received adjuvant endocrine therapy and went on to develop metastatic disease, or never received adjuvant endocrine therapy for another reason.

Additional correlative work will come out in the ensuing years, especially to understand the issues of de novo endocrine resistance versus secondary endocrine resistance, Marcom says. It could be practice changing to have standard frontline therapy include fulvestrant versus an aromatase inhibitor.

Selective estrogen receptor downregulators, he adds, will likely be the go-to agent in combinations with the appropriate targeted therapy.