Expanding Oral Therapy Options for ER+ Advanced Breast Cancer

The development of new oral selective estrogen-receptor degraders (SERDs) has increased the treatment options for metastatic ER+/HER2− breast cancer. Imlunestrant is a brain-penetrant SERD shown to have clinical activity in endocrine-refractory tumors, including those that develop ESR1 mutations. It is not yet FDA approved.

In the industry-sponsored, open-label, phase 3 EMBER-3 trial, 874 patients with ER+/HER2− metastatic breast cancer were randomized to standard of care endocrine therapy (SOC; fulvestrant or exemestane), imlunestrant monotherapy, or imlunestrant plus abemaciclib. Eligible patients had disease progression during or within 12 months after neoadjuvant or adjuvant treatment with an aromatase inhibitor (with or without a CDK4/6…