elacestrant
Orserdu (elacestrant) is an oral selective estrogen receptor degrader from Stemline. It binds the estrogen receptor and marks it for destruction, and is used in ER-positive, HER2-negative advanced breast cancer with an ESR1 mutation after prior endocrine therapy.
This page is based on FDA prescribing information and the EMA medicine record for elacestrant, cross-checked with DailyMed and MedlinePlus; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
Some breast cancers are machines that run on the estrogen receptor, and ESR1 mutations are like wiring the machine to ignore the off switch. Older medicines block the fuel; elacestrant goes further - it unscrews the switch from the wall and sends it for recycling, so the machine loses its controls entirely.
In simple terms
ER-positive breast cancers grow in response to estrogen acting on the estrogen receptor. After treatment with standard hormone therapies, cancers often develop ESR1 mutations that keep the receptor active on its own. Elacestrant binds the receptor and changes its shape so the cell tags it for destruction. With the receptor removed, the growth signal stops, slowing or shrinking the cancer.
In depth
Elacestrant is an orally bioavailable selective estrogen receptor degrader. It binds ER-alpha with high affinity, induces a conformational change that reduces receptor stability and promotes proteasomal degradation, and suppresses ER-mediated transcription more completely than selective modulators. Activity in ESR1-mutant tumours, where the receptor signals ligand-independently, established it as an option after progression on aromatase inhibitors and CDK4/6 inhibitors.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How elacestrant flags the estrogen receptor for destruction
- Some breast cancers are machines that run on the estrogen receptor, and ESR1 mutations are like wiring the machine to ignore the off switch.
- Elacestrant binds the receptor and changes its shape so the cell tags it for destruction.
- Removing the receptor matters because ESR1 mutations can keep it switched on even when estrogen is blocked.
- With the receptor removed, the growth signal stops, slowing or shrinking the cancer.
Target: Estrogen receptor (ER)
A hormone receptor that drives growth of many breast cancers; mutations in its gene, ESR1, can keep it switched on even when estrogen is blocked, so removing the receptor itself becomes necessary.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- Treatment of postmenopausal women or adult men with estrogen receptor-positive, HER2-negative, ESR1-mutated advanced or metastatic breast cancer, as detected by an FDA-authorized test, with disease progression following at least one line of endocrine therapy
Approved uses in European Union
EMA- As monotherapy, for postmenopausal women and men with estrogen receptor-positive, HER2-negative, locally advanced or metastatic breast cancer with an activating ESR1 mutation who have disease progression following at least one line of endocrine therapy including a CDK4/6 inhibitor
Official sources
The statements on this page trace back to these records.
- Orserdu (elacestrant) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- DailyMed: Orserdu (elacestrant) label
DailyMed, U.S. National Library of Medicine
- U.S. Food and Drug Administration: elacestrant prescribing information
U.S. Food and Drug Administration
- MedlinePlus: elacestrant
MedlinePlus, U.S. National Library of Medicine
- National Cancer Institute: elacestrant hydrochloride
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.