Research table: Oral selective estrogen receptor degraders (SERDs) for metastatic breast cancer treatment

This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.

Introduction: Selective estrogen receptor degraders (SERDs) are a type of hormone therapy. These anti-estrogen drugs bind to the estrogen receptor in a tumor cell. They cause the receptor to be broken down by the cell.

Some SERDs are in pill form (taken orally).

The oral SERDs elacestrant (Orserdu) and imlunestrant (Inluriyo) are FDA-approved for use in metastatic breast cancer treatment. They can each be used to treat hormone receptor-positive, HER2-negative metastatic breast cancers that have an ESR1 tumor gene mutation and have been treated with hormone therapy in the metastatic setting. (The ESR1 mutation is in the genes of the breast cancer cells, not the genes of the person.)

The American Society of Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCN) recommend all hormone receptor-positive, HER2-negative metastatic breast cancers be tested for ESR1 tumor gene mutations to see if elacestrant or imlunestrant can be used for treatment [1-2].

Learn more about elacestrant and imlunestrant, including their side effects.

Learn about guidelines for the treatment of metastatic breast cancer.

Learn about the strengths and weaknesses of different types of studies.

Study selection criteria: Randomized clinical trials with 100 or more participants with hormone receptor-positive, HER2-negative metastatic breast cancer that had an ESR1 tumor gene mutation.

Study	Study Population (number of participants)	Drug(s) Used	Objective Response Rate-Percent who Responded to Treatment (95% CI)	Overall Survival (95% CI)
Randomized clinical trials
EMBER study [3]	256	Imlunestrant		Overall survival at 18 months: 77%*
		Fulvestrant or exemestane alone		Overall survival at 18 months: 59%*
EMERALD trial [4]	228	Elacestrant	7% NS	Overall survival at 1 year: 83%*
		Fulvestrant, anastrozole, letrozole or exemestane alone	5% NS	Overall survival at 1 year: 74%*

NS = No statistically significant difference between the 2 treatment groups

* Statistically significant difference between the 2 treatment groups.

References

Burstein HJ, DeMichele A, Somerfield MR, Henry NL for the Biomarker Testing and Endocrine and Targeted Therapy in Metastatic Breast Cancer Expert Panels. Testing for ESR1 mutations to guide therapy for hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer: ASCO Guideline Rapid Recommendation Update. J Clin Oncol. 41(18):3423-3425, 2023.
National Comprehensive Cancer Network (NCCN). NCCN Clinical practice guidelines in oncology: Breast cancer V.4.2025. https://www.nccn.org/, 2025.
Jhaveri KL, Neven P, Casalnuovo ML, et al. for the EMBER-3 Study Group. Imlunestrant with or without abemaciclib in advanced breast cancer. N Engl J Med. 392(12):1189-1202, 2025.
Bidard FC, Kaklamani VG, Neven P, et al. Elacestrant (oral selective estrogen receptor degrader) versus standard endocrine therapy for estrogen receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer: results from the randomized phase III EMERALD Trial. J Clin Oncol. 40(28):3246-3256, 2022.

Updated 10/13/25