Dr. Bardia on Elacestrant in ER+/HER2– Metastatic Breast Cancer

Aditya Bardia, MD, MPH, attending physician, medical oncology, Massachusetts General Hospital; associate professor, medicine, Harvard Medical School, discusses the use of elacestrant in patients with estrogen receptor (ER)–positive, HER2-negative metastatic breast cancer.

The phase 3 EMERALD trial (NCT03778931) investigated elacestrant, a novel endocrine agent, vs standard-of-care endocrine therapy in the ER-positive, HER2-negative population. EMERALD aimed to identify an endocrine-sensitive disease subgroup that would benefit from elacestrant vs standard endocrine therapy, Bardia says. EMERALD used prior use of CDK4/6 inhibitors as a surrogate marker for endocrine-sensitive disease and found that a longer duration of prior CDK4/6 inhibition was associated with a prolonged median progression-free survival (PFS) benefit from elacestrant, as well as a PFS benefit at 6, 12, and 18 months, Bardia explains.

For example, patients with ESR1-mutant tumors who had received prior CDK4/6 inhibition for at least 12 months experienced a median PFS of 8.61 months with elacestrant vs 1.91 months with standard endocrine therapy, Bardia emphasizes. These data indicate that prior duration of CDK4/6 inhibition is predictive of endocrine-sensitive disease, and that elacestrant provides a PFS benefit for these patients, Bardia concludes.