Biomarker · Hormone receptor

Estrogen receptor (ER)

Estrogen receptor protein expression measured by immunohistochemistry on tumor tissue; used as a predictive marker for endocrine therapy and as part of breast cancer subtyping.

CI-BIO-00000002ESR1 graph →NCIt C15492

Also calledER · ER-positive · ESR1 expression · estrogen receptor alpha

Derived

Associated cancers (1)

Cancers mapped in ACCEPTED CIViC predictive, prognostic or diagnostic items whose variant (molecular markers) or gene (gene-level markers) is in this biomarker's scope. Counts by type and native level; each row links to the cancer's evidence tab.

Computedrule biomarker-links-v1

Cancer	Items	Predictive	Prognostic	Diagnostic	Levels A / B / C / D / E
Malignant Breast Neoplasm	14	14	—	—	1 / 2 / 1 / 10 / 0

Derived

Drugs with predictive evidence (7)

Therapies named in in-scope PREDICTIVE CIViC items, plus targets of PREDICTS_RESPONSE_TO knowledge edges from in-scope variants. Sensitivity and resistance are counted separately and never merged into a verdict.

Computedrule biomarker-links-v1

Drug	CIViC items	Sensitivity	Resistance	Best level	Edges (S / R)	Cancer context
FulvestrantSmall Molecule	6	5	1	B	5 / 1	Malignant Breast Neoplasm
Hormone Therapy	5	—	5	D	0 / 5	Malignant Breast Neoplasm
TamoxifenSmall Molecule

Curated evidence

Predictive evidence items (15)

ACCEPTED CIViC predictive items in scope, grouped by molecular profile and therapy with native level, direction and cancer context. 50 per page.

civicCuratedShowing 1–15 of 15 evidence items · levels, directions and significance as curated at the source; each row links to its CIViC record.

Therapy	Cancer	Type	Level	Direction · significance	Rating (1–5)	Status	Evidence	Source
ESR1 Mutation1
Elacestrant

Regulatory

Approvals mentioning the linked drugs (186)

Approval records of the derived drug set, plus records whose indication text names this biomarker. Each record names its authority, jurisdiction, indication text and status — a drug approved in one jurisdiction for one indication is not 'approved' in general, and an approval listed here is not necessarily restricted to this biomarker.

Computedrule biomarker-links-v1

openfda

Clinical trials

Active trials (177)

Trials with an active ClinicalTrials.gov status, an intervention mapped to a derived drug and a condition mapped to an associated cancer. 87 recruiting · 47 active phase 3 · 688 in any status. Most recently updated first, 50 per page.

Computedrule biomarker-links-v1

clinicaltrialsPublishedShowing 1–50 of 177 active studies · status and phase as posted by the registrant; each row links to the study record.

NCT	Title	Status	Phase	Enrollment (n)	Sponsor	Countries	Last update	Source
NCT05646862	A Study Evaluating the Efficacy and Safety of Inavolisib Plus Fulvestrant Compared With Alpelisib Plus Fulvestrant in Participants With HR-Positive, HER2-Negative, PIK3CA Mutated, Locally Advanced or Metastatic Breast Cancer Post CDK4/6i and Endocrine Combination Therapy

Literature

Linked publications (6)

Publications linked to the scope gene(s) through PubMed entity edges; 25 per page, newest first.

pubmedPublishedShowing 1–6 of 6 publications · bibliographic data as recorded by PubMed; abstracts are not reproduced.

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 · 2022 · PMID 35584336 · validated civic_curation pubmed
The cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with letrozole versus letrozole alone as first-line treatment of oestrogen receptor-positive, HER2-negative, advanced breast cancer (PALOMA-1/TRIO-18): a randomised phase 2 study.
· Lancet Oncol · 2015 · PMID 25524798 · validated civic_curation pubmed
The Genetic Landscape and Clonal Evolution of Breast Cancer Resistance to Palbociclib plus Fulvestrant in the PALOMA-3 Trial.
· Cancer Discov · 2018 · PMID 30206110 · validated civic_curation pubmed

ESR1 Mutation + PIK3CA Mutation + RB1 MutationPIK3CA RB1 ESR11
Fulvestrant + PalbociclibCombination	Malignant Breast Neoplasm	Predictive	B	Supports Resistance	3	accepted	EID12045 In this phase III trial (PALOMA-3), patients with ER+, HER2- advanced breast cancer were treated with CDK4/6 inhibitors. Patients were randomized to receive palbociclib plus fulvestrant (P+F) or place… (full text at CIViC) PMID 30206110 · O'Leary et al., 2018 · Open in CIViC	civic

ESR1 Mutation + PIK3CA Mutation + RB1 MutationPIK3CA RB1 ESR11

Drug	Jurisdiction · authority	Cancer	Indication	Status	Approval date	Source
Abemaciclib	US FDA	Malignant Breast Neoplasm	in combination with an aromatase inhibitor as initial endocrine-based therapy for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer.	approved	Sep 28, 2017	openfda
Abemaciclib	US FDA	Malignant Breast Neoplasm	in combination with endocrine therapy (tamoxifen or an aromatase inhibitor) for the adjuvant treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive, early breast cancer at high risk of recurrence.	approved	Sep 28, 2017	openfda
Abemaciclib	US FDA	Malignant Breast Neoplasm	in combination with fulvestrant for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer with disease progression following endocrine therapy.	approved	Sep 28, 2017	openfda
Alpelisib	EU EMA	Malignant Breast Neoplasm	Piqray is indicated in combination with fulvestrant for the treatment of postmenopausal women, and men, with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, locally advanced or metastatic breast cancer with a PIK3CA mutation after disease progression following endocrine therapy as monotherapy (see section 5.1).	approved	Jul 27, 2020	ema
Alpelisib	US FDA	Malignant Breast Neoplasm	PIQRAY is indicated in combination with fulvestrant for the treatment of adults with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, advanced or metastatic breast cancer as detected by an FDA-approved test following progression on or after an endocrine-based regimen. PIQRAY is a kinase inhibitor indicated in combination with fulvestrant for the treatment of adults with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, advanced or metastatic breast cancer as detected by an FDA-approved test following progression on or after an endocrine-based regimen.	approved	May 24, 2019	openfda
Anastrozole	US FDA	Malignant Breast Neoplasm	Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer	approved	Dec 27, 1995	openfda
Anastrozole	US FDA	Malignant Breast Neoplasm	First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor-unknown locally advanced or metastatic breast cancer	approved	Dec 27, 1995	openfda
Camizestrant	EU EMA	—	Etcamah in combination with a CDK4/6 inhibitor (palbociclib, ribociclib, or abemaciclib) is indicated for the treatment of adult patients with ER-positive, HER2-negative, locally advanced or metastatic breast cancer upon detection of ESR1‑mutation and without disease progression during first-line endocrine therapy in combination with a CDK4/6 inhibitor (for biomarker based patient-selection, see section 4.2 and 5.1).	approved	Jul 20, 2026	ema
Capivasertib	US FDA	Malignant Breast Neoplasm	HR positive, HER2 negative locally advanced or metastatic breast cancer • in combination with fulvestrant for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, locally advanced or metastatic breast cancer with one or more PIK3CA/AKT1/PTEN -alterations as detected by an FDA-authorized test following progression on at least one endocrine-based regimen in the metastatic setting or recurrence on or within 12 months of completing adjuvant therapy.	approved	Nov 16, 2023	openfda
Datopotamab Deruxtecan	EU EMA	Malignant Breast Neoplasm	Breast cancerDatroway as monotherapy is indicated for the treatment of adult patients with unresectable or metastatic hormone receptor (HR)-positive, HER2-negative breast cancer who have received endocrine therapy and at least one line of chemotherapy in the advanced setting.	approved	Apr 4, 2025	ema
Datopotamab Deruxtecan	US FDA	Malignant Breast Neoplasm	adult patients with unresectable or metastatic, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative (IHC 0, IHC 1+ or IHC 2+/ISH-) breast cancer who have received prior endocrine-based therapy and chemotherapy for unresectable or metastatic disease.	approved	Jan 17, 2025	openfda
Elacestrant	EU EMA	Malignant Breast Neoplasm	Orserdu monotherapy is indicated for the treatment of postmenopausal women, and men, with estrogen receptor (ER) 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 CDK 4/6 inhibitor.	approved	Sep 15, 2023	ema
Elacestrant	US FDA	Malignant Breast Neoplasm	ORSERDU is indicated for the treatment of postmenopausal women or adult men with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)‑negative, ESR1 -mutated advanced or metastatic breast cancer, as detected by an FDA-authorized test [see Dosage and Administration ( 2.1 )] , with disease progression following at least one line of endocrine therapy. ORSERDU is an estrogen receptor antagonist indicated for: treatment of postmenopausal women or adult men, with ER-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 ( 1 )	approved	Jan 27, 2023	openfda
Everolimus	US FDA	Malignant Breast Neoplasm	Postmenopausal women with advanced hormone receptor-positive, HER2-negative breast cancer in combination with exemestane after failure of treatment with letrozole or anastrozole.	approved	Aug 29, 2012	openfda
Everolimus	US FDA	Malignant Breast Neoplasm	Postmenopausal women with advanced hormone receptor-positive, HER2-negative breast cancer in combination with exemestane after failure of treatment with letrozole or anastrozole.	approved	Mar 30, 2009	openfda
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02558971) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approvedsource: Marketed	Sep 30, 2025	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTABLE (DIN 02530635) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approvedsource: Marketed	Sep 12, 2024	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02536293) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approvedsource: Marketed	Dec 18, 2023	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02486792) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	withdrawnsource: Cancelled Post Marketsince Nov 1, 2024	Mar 2, 2022	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02468549) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	withdrawnsource: Cancelled Post Marketsince Mar 31, 2025	Apr 27, 2020	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02483610) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approvedsource: Marketed	Feb 1, 2019	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as TEVA-FULVESTRANT INJECTION (DIN 02460130) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approvedsource: Marketed	Jan 15, 2019	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FASLODEX (DIN 02248624) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approvedsource: Marketed	Jun 14, 2004	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as APO-FULVESTRANT (DIN 02486350) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approved	—	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as ACT FULVESTRANT (DIN 02463075) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	withdrawnsource: Cancelled Pre Marketsince Apr 23, 2020	—	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02536668) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approved	—	health-canada-dpd
Fulvestrant	CA Health Canada	—	Marketed in Canada as FULVESTRANT INJECTION (DIN 02533111) under ATC L02BA03 FULVESTRANT. Indications are not published in the Drug Product Database — see the Health Canada Product Monograph.	approved	—	health-canada-dpd
Fulvestrant	EU EMA	Malignant Breast Neoplasm	Fulvestrant is indicated for the treatment of estrogen receptor positive, locally advanced or metastatic breast cancer in postmenopausal women: not previously treated with endocrine therapy, or with disease relapse on or after adjuvant anti-estrogen therapy, or disease progression on antiestrogen therapy.	approved	Jan 8, 2018	ema
Fulvestrant	EU EMA	Malignant Breast Neoplasm	Faslodex is indicated as monotherapy for the treatment of estrogen receptor positive, locally advanced or metastatic breast cancer in postmenopausal women: not previously treated with endocrine therapy, or with disease relapse on or after adjuvant antiestrogen therapy, or disease progression on antiestrogen therapy. in combination with palbociclib for the treatment of hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative locally advanced or metastatic breast cancer in women who have received prior endocrine therapy. In pre- or perimenopausal women, the combination treatment with palbociclib should be combined with a luteinizing hormone releasing hormone (LHRH) agonist.	approved	Mar 9, 2004	ema
Fulvestrant	US FDA	—	Efficacy supplement 2021-05-12 (see label)	approved	May 12, 2021	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2020-07-28 (see label)	approved	Jul 28, 2020	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2020-05-13 (see label)	approved	May 13, 2020	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2019-11-21 (see label)	approved	Nov 21, 2019	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	Monotherapy CLIGAVYX is indicated for the treatment of: Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer in postmenopausal women not previously treated with endocrine therapy, or HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy. Combination Therapy CLIGAVYX is indicated for the treatment of: HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib as initial endocrine based therapy or following disease progression on endocrine therapy. HR-positive, HER2-negative advanced or metastatic breast cancer in combination with palbociclib or abemaciclib in women with disease progression after endocrine therapy. CLIGAVYX is an estrogen receptor antagonist indicated for the treatment of: Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer in postmenopausal women not previously treated with endocrine therapy. ( 1 ) HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy. ( 1 ) HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib, as initial endocrine based therapy or following disease progression on endocrine therapy. ( 1 ) HR-positive, HER2-negative advanced or metastatic breast cancer in combination with palbociclib or abemaciclib in women with disease progression after endocrine therapy. ( 1 )	approved	Aug 19, 2019	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	Fulvestrant Injection is an estrogen receptor antagonist indicated for the treatment of: Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer in postmenopausal women not previously treated with endocrine therapy. ( 1 ) HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy. ( 1 ) HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib, as initial endocrine based therapy or following disease progression on endocrine therapy. ( 1 ) HR-positive, HER2-negative advanced or metastatic breast cancer in combination with palbociclib or abemaciclib in women with disease progression after endocrine therapy. ( 1 ) Monotherapy Fulvestrant Injection is indicated for the treatment of: Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer in postmenopausal women not previously treated with endocrine therapy, or HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy. Combination Therapy Fulvestrant Injection is indicated for the treatment of: HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib as initial endocrine based therapy or following disease progression on endocrine therapy. HR-positive, HER2-negative advanced or metastatic breast cancer in combination with palbociclib or abemaciclib in women with disease progression after endocrine therapy.	approved	May 20, 2019	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2019-03-11 (see label)	approved	Mar 11, 2019	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2018-07-05 (see label)	approved	Jul 5, 2018	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2017-11-14 (see label)	approved	Nov 14, 2017	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2017-08-25 (see label)	approved	Aug 25, 2017	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2016-03-02 (see label)	approved	Mar 2, 2016	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2012-11-09 (see label)	approved	Nov 9, 2012	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2011-05-17 (see label)	approved	May 17, 2011	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2010-09-09 (see label)	approved	Sep 9, 2010	openfda
Fulvestrant	US FDA	—	Efficacy supplement 2003-12-24 (see label)	approved	Dec 24, 2003	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	HR-positive, HER2-negative advanced or metastatic breast cancer in combination with palbociclib or abemaciclib in women with disease progression after endocrine therapy. FASLODEX is an estrogen receptor antagonist indicated for the treatment of:	approved	Apr 25, 2002	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer in postmenopausal women not previously treated with endocrine therapy, or	approved	Apr 25, 2002	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy. Combination Therapy FASLODEX is indicated for the treatment of:	approved	Apr 25, 2002	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib as initial endocrine based therapy or following disease progression on endocrine therapy.	approved	Apr 25, 2002	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	HR-positive advanced breast cancer in postmenopausal women with disease progression following endocrine therapy. (1)	approved	Apr 25, 2002	openfda
Fulvestrant	US FDA	Malignant Breast Neoplasm	HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women in combination with ribociclib, as initial endocrine based therapy or following disease progression on endocrine therapy. (1)	approved	Apr 25, 2002	openfda