12 EMERALD Trial Analysis of Patient-Reported Outcomes (PROs) in Patients (pts) With ER+/HER2- Advanced or Metastatic Breast Cancer (mBC) Comparing Oral Elacestrant vs Standard-of-Care (SoC) Endocrine Therapy

12 EMERALD Trial Analysis of Patient-Reported Outcomes (PROs) in Patients (pts) With ER+/HER2- Advanced or Metastatic Breast
Cancer (mBC) Comparing Oral Elacestrant vs Standard-of-Care (SoC) Endocrine Therapy

Background

Endocrine therapy (ET) plus a CDK4/6 inhibitor is the mainstay for the management of estrogen receptor–positive (ER+)/HER2-negative (HER–) metastatic breast cancer (mBC) as first-line (1L) therapy; however, tumors eventually develop resistance to ET. ESR1 mutations represent a type of acquired resistance in up to 40% of patients that predominantly occurs after ET, particularly aromatase inhibitors, reducing the efficacy of available regimens. In the EMERALD trial (NCT03778931), single-agent elacestrant was associated with significantly prolonged PFS and a manageable safety profile vs standard-of-care (SOC) ET in patients with ER+/HER2–, ESR1-mutated advanced/mBC, leading to the first oral selective estrogen receptor degrader approved. Patients receiving elacestrant demonstrated a median progression-free survival (PFS) of 3.8 months vs 1.9 months with SOC ET (Bidard, 2022). Patients who had received 12 months or more of prior CDK4/6 inhibitors experienced a median PFS of 8.6 months with elacestrant vs 1.9 months with SOC ET (SABCS, 2022). Patient-reported outcomes (PROs) measuring quality of life (QOL) are reported here.

Methods

Patients enrolled on EMERALD completed 3 PRO tools at prespecified time points: the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), the PRO version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE), and the EuroQoL 5 Dimension 5 Level (EQ-5D-5L).

Results

The ratio of PRO tools completed vs PRO tools expected was 80% to 90% through cycle 4 and approximately 70% at cycle 6, likely due to the clinical study period overlapping with the COVID-19 period. QOL was maintained between treatment groups (elacestrant vs SOC) in the EMERALD trial. No differences were observed between all patients and those with ESR1-mutated tumors. The EORTC-QLQ-C30 scores showed no differences for functional, symptom, and QOL domains. The PRO-CTCAE results showed no clinically meaningful differences in adverse effects of interest, such as nausea, vomiting, fatigue, joint and muscle pain, and hot flashes. The EQ-5D-5L scores were comparable across treatment groups for mobility, self-care, and usual activities.

Conclusions

This analysis confirms that QOL was maintained between treatment groups in the EMERALD trial, including those patients with ESR1-mutated tumors. These results provide additional evidence that oral elacestrant is clinically meaningful while maintaining QOL in this patient population with limited therapeutic options.