ESR1 mutation

Approved therapies

Approvals in the United States (FDA) and the European Union (EMA), one row per drug, regimen and tumour type. Where we have them, the pivotal trial's results and side effects are shown under each therapy, from the official label. Results from different trials are not directly comparable: patients, earlier treatments and comparators differ.

Companion diagnostic tests

Tests the FDA has approved to select patients for a specific therapy. Other validated tests are often used in practice, especially in Europe.

Drugs in active trials

Targeted drugs, antibody-drug conjugates and immunotherapies in active trials on this page, approved ones first, then by the furthest phase reached. Chemotherapy and supportive medicines are left out. "Not yet classified" means an early drug known only by its code.

11 of 11 drugs shown

Upcoming readouts

Active phase 2 and 3 trials whose primary completion date falls in the next 12 months: the date the main results are due to be collected, according to the sponsor. Results are usually published months later, and these dates often slip.

Companies

Industry sponsors leading active trials, by number of trials. Each square is one trial, shaded by phase.

1. AstraZeneca 1
2. LeonaBio 1
3. Stemline Therapeutics 1
4. Forward Pharmaceuticals 1

Phase 1 Phase 2 Phase 3 Phase 4 No phase

Trials

Matched automatically from registry text, so a few trials may only mention ESR1 mutation rather than require it. Check the quoted criterion, and the registry entry before relying on a match.

9 of 19 trials shown

1. Elacestrant + Everolimus in Patients ER+/HER2-, ESR1mut, Advanced Breast Cancer Progressing to ET and CDK4/6i.

   Recruiting Phase 3 MedSIR Started 2024Primary completion 2027-09 NCT06382948

   everolimuselacestrant FDA EUdexamethasoneAuxiliary Medicinal Product - Luteinizing hormone-releasing hormone (LHRH) analo

   Elacestrant + Everolimus in Patients ER+/HER2-, ESR1mut, Advanced Breast Cancer Progressing to ET and CDK4/6i.

   Advanced Breast Cancer, ER-positive Breast Cancer, HER2-negative Breast Cancer, ESR1 Gene Mutation

2. Evaluation of Lasofoxifene Combined With Abemaciclib Compared With Fulvestrant Combined With Abemaciclib in Locally Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation

   Recruiting Phase 3 LeonaBio Started 2023Primary completion 2027-04 NCT05696626

   lasofoxifeneabemaciclib FDAfulvestrant

   At least 1 or more ESR1 point mutations in the ESR1 ligand binding domain as assessed in cell- free ctDNA obtained from a blood or breast can…

   Metastatic Breast Cancer

3. Phase III Study to Assess AZD9833+ CDK4/6 Inhibitor in HR+/HER2-MBC With Detectable ESR1m Before Progression (SERENA-6)

   Active, not recruiting Phase 3 AstraZeneca Started 2021Primary completion 2025-06 NCT04964934

   camizestrant FDAanastrozoleletrozolepalbociclibabemaciclib FDALuteinizing hormone-releasing hormone (LHRH) agonistribociclib

   Have an ESR1 mutation in their cancer;

   ER-Positive HER2-Negative Breast Cancer

4. PhII Randomized CAPecitabine + ELAcestrant vs. Capecitabine Alone in ER+ Breast Cancer (CAPELA)

   Recruiting Phase 2 Kristina A. Fanucci Started 2026Primary completion 2029-12 NCT07222215

   capecitabineelacestrant FDA EU

   ESR1 mutations that are considered pathogenic are: E380Q, V422del, S436P, L536H, L536P, L536R, Y537C, Y5…

   Estrogen-receptor-positive Breast Cancer, Metastatic Breast Cancer, Breast Cancer, Hormone Receptor Positive Breast Cancer

5. A Phase 2 Bridging Study of Elacestrant Monotherapy in Advanced or Metastatic Breast Cancer

   Recruiting Phase 2 Stemline Therapeutics Started 2026Primary completion 2028-10 NCT07766018

   elacestrant FDA EU

   Participants must be ESR1-mutant positive determined via testing with the Guardant360 Companion Diagnostic panel test prio…

   Breast Cancer

6. Elacestrant vs Elacestrant Plus a CDK4/6 Inhibitor in Patients With ERpositive/HER2-negative Advanced or Metastatic Breast Cancer

   Recruiting Phase 2 Northwestern University Started 2023Primary completion 2028-07 NCT06062498

   elacestrant FDA EUpalbociclibabemaciclib FDAribociclib

   Patients must have a confirmed ESR1 mutation.

   Estrogen-receptor-positive Breast Cancer, HER2/Neu-Negative Breast Cancer, Advanced Breast Cancerv, Metastatic Breast Cancer

7. A Phase I/II Study of FWD1802 in Patients With ER+/HER2- Advanced BC.

   Recruiting Phase 1/2 Forward Pharmaceuticals Started 2023Primary completion 2026-03 NCT06064812

   FWD1802

   Phase II Study: Only subjects with confirmed ESR1 mutations will be enrolled (see Appendix 5 for details).

   Metastatic Breast Cancer, Locally Advanced Breast Cancer, Breast Cancer Stage IV, ER+/HER2- Breast Cancer

8. Immunologic Targeting of ESR1 Receptor for Hormone Receptor Expressing Metastatic Breast Cancer

   Active, not recruiting Phase 1 H. Lee Moffitt Cancer Center and Research Institute Started 2024Primary completion 2026-11 NCT06691035

   elacestrant FDA EUDC1 native/mutated ESR1

   Participants must have Presence of an ESR1 mutation detected via tissue based or blood based (ctDNA) genomic profiling.

   Breast Cancer Metastatic Breast Cancer, HER2-negative Breast Cancer

9. FES Imaging to Optimize Tamoxifen for Metastatic Breast Cancer

   Recruiting Early Phase 1 University of Wisconsin, Madison Started 2020Primary completion 2026-12 NCT04174352

   Tamoxifen

   ESR1 mutation identified using a Clinical Laboratory Improvement Amendments (CLIA) certified assay via …

   ERα+ Breast Cancer, ESR1 Gene Mutation

No trials match these filters.