Elacestrant in Patients With ER+ HER2- ESR1-mutated Locally Advanced or Metastatic Breast Cancer (ELENI)

Elacestrant in Patients With ER+ HER2- ESR1-mutated Locally Advanced or Metastatic Breast Cancer: a Multicenter, National, Prospective Non-interventional Study

The objective of this non-interventional study (NIS) is to evaluate prevalence of ESR1 mutation after endocrine therapy in the palliative setting, quality of life, tolerability, and safety and to describe treatment detail and adverse event (AE) management in postmenopausal women with locally advanced and/or metastatic ER+ HER2- ESR1-mutated breast cancer and second line treatment with elacestrant according to SmPC (Summary of product characteristics) in a real-world setting.

Study Overview

• Status: Not yet recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Drug: Standard of care (Investigator Choice); Drug: Elacestrant

• Study Type: Observational
• Enrollment (Estimated): 500

Contacts and Locations

• Study Contact: Name: Laura Serrer; Phone Number: +49761152420; Email: eleni@iomedico.com

Study Locations

• Germany
  • Paderborn, Germany, 33098
    • St. Louise Frauen- und Kinderklinik
    • Contact: Michael P Lux; Phone Number: +49 5251864121; Email: M.Lux@vincenz.de
  • Ravensburg, Germany, 88212
    • Gemeinschaftspraxis für Hämatologie und Onkologie
    • Contact: Thomas Decker; Phone Number: +49 751 366197-0; Email: thomas.decker@onkonet.eu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Postmenopausal women with locally advanced and/or metastatic estrogen receptor-positive (ER+) human epidermal growth factor receptor 2-negative (HER2)- breast cancer with disease progression on endocrine therapy and cyclin-dependent kinase inhibitor (CDKi) and intention for second line (2L) treatment with elacestrant according to summary of product characteristics (SmPC).

Description

Inclusion Criteria:

• Signed and dated informed consent form
• Postmenopausal women
• Age ≥18 years
• Eastern Cooperative Oncology Group Performance Status (ECOG) < 2
• Locally advanced and/or metastatic ER+ HER2- breast cancer
• Histologically proven ER positivity (defined as ≥1% staining by immunohistochemistry (IHC))
• Histologically proven HER2 negativity (defined as a IHC0 or IHC1+ score by IHC or a negative result by in situ hybridization (ISH), optionally combined with a IHC2+ score)
• Disease progression following first line ET + CDKi
• No more than one prior ET line in the advanced/metastatic setting and intention for 2nd-line treatment with elacestrant according to current elacestrant SmPC as assessed by the treating physician (ESR1 testing can be done after inclusion)
• For patients with proven ESR1mut: Study inclusion the latest 2 weeks after start of elacestrant treatment

Exclusion Criteria

• Prior chemotherapy in the advanced/metastatic setting
• Contraindications according to elacestrant SmPC, except for ESR1 test result for patients included prior to ESR1 testing.
• Participation in an interventional clinical trial within 30 days prior to enrolment or simultaneous participation in an interventional clinical trial (except follow-up phase)

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
ESR1 wildtype; Patients with a ESR1 wildtype tumor	Drug: Standard of care (Investigator Choice); Treatment decision of investigator
ESR1 mutated; Patients with a ESR1 mutated tumor	Drug: Elacestrant; According to the Summary of Product Characteristics (SmPC); Other Names: Orserdu®

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in EORTC global health scale	Change from baseline quality of life (QoL) over time for the global health scale of the EORTC QLQ- C30 questionnaire The EORTC QLQ- C30 global health scale ranges from 0 to 100, with higher scores indicating better quality of life.	From Time of enrollment until month 11

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assess parameters of physicians' treatment decision making using a questionnaire	Frequency of distinct parameters affecting therapy choice; questionnaire completed by treating physician.	Baseline
Time to deterioration in global health scale (EORTC QLQ-C30)	Time to deterioration in global health scale of EORTC QLQ-C30 The EORTC QLQ- C30 global health scale ranges from 0 to 100, with higher scores indicating better quality of life.	From Time of enrollment until month 11
Time to deterioration in functional scores (EORTC QLQ-C30)	Time to deterioration in functional scores of EORTC QLQ-C30. The EORTC QLQ- C30 functional score ranges from 0 to 100, with higher scores indicating better quality of life.	From Time of enrollment until month 11
Time to deterioration in symptom scores (EORTC QLQ-C30)	Time to deterioration in symptom scores of EORTC QLQ-C30 The EORTC QLQ- C30 symptom score ranges from 0 to 100, with lower scores indicating better quality of life.	From Time of enrollment until month 11
Change from baseline in functional and symptom scores	Change from baseline in functional and symptom scores of EORTC QLQ-C30 The EORTC QLQ- C30 functional and symptom scores ranges from 0 to 100, with higher scores indicating better quality of life (for functional scores), and lower indication better quality of life for symptom scores.	From Time of enrolment until up to 11 months after enrolment.
Change from baseline in visual analogue scale (VAS)	Change from baseline in EQ-5D-5L visual analogue scale (VAS); The EQ-5D-5L VAS ranges from 0 to 100, with higher scores indicating better quality of life.	From Time of enrollment until month 11.
Change from baseline in index value	Change from baseline in EQ-5D-5L Index Value The EQ-5D-5L index value ranges from -0.661 to 1, with higher scores indicating better quality of life.	From Time of enrollment until month 11.
Change from baseline in all scales of EQ-5D-5L	Change from baseline in all scales of EQ-5D-5L The scales of EQ-5D-5L range from 1 to 5, with lower scores indicating better quality of life.	From Time of enrollment until month 11.
Prevalence of ESR1 mutation	Assess prevalence of ESR1mut in patients intended for elacestrant treatment as well as the testing methodology and results for ESR1 mutations.	Baseline
Drug safety: Frequency	Frequency of specific (serious) adverse drug reactions ((S)ADRs) (nausea, vomiting, decreased appetite)	From time of treatment start until 30 days after end of elacestrant treatment
Drug safety: Incidence of adverse events	Incidence of (serious) adverse events ((S)AEs), (serious) adverse drug reactions ((S)ADRs)	From time of treatment start until 30 days after end of elacestrant treatment
Drug safety: Change from baseline in AST (Aspartate Aminotransferase)	Change from baseline in AST	From time of treatment start until 30 days after end of elacestrant treatment (max. 24 months)
Drug safety: Change from baseline in ALT (Alanine Aminotransferase)	Change from baseline in ALT	From time of treatment start until 30 days after end of elacestrant treatment (max. 24 months)
Drug safety: Change from baseline in bilirubin	Change from baseline in bilirubin	From time of treatment start until 30 days after end of elacestrant treatment (max. 24 months)
Patients and disease characteristics: Age	Assess patients characteristics in patients with intention for treatment with elacestrant: Age (descriptive statistics, categorical (</≥ 65))	Baseline
Patients and disease characteristics: Body mass index (BMI)	Assess patients characteristics in patients with intention for treatment with elacestrant: BMI (descriptive statistics, categorical (underweight, normal weight, overweight, obese))	Baseline
Patients and disease characteristics: ECOG Performance status	Assess patients characteristics in patients with intention for treatment with elacestrant: ECOG Performance status	Baseline
Patients and disease characteristics: CCI (Charlson score and contributing diseases)	Assess patients characteristics in patients with intention for treatment with elacestrant: CCI (Charlson score and contributing diseases)	Baseline
Patients and disease characteristics: Time since diagnosis	Assess disease characteristics in patients with intention for treatment with elacestrant: Time since diagnosis (descriptive statistics)	Baseline
Patients and disease characteristics: TNM staging	Assess disease characteristics in patients with intention for treatment with elacestrant: TNM staging (including AJCC) at initial diagnosis	Baseline
Patients and disease characteristics: Metastatic sites	Assess disease characteristics in patients with intention for treatment with elacestrant: • Metastatic sites at inclusion	Baseline
Patients and disease characteristics: Tumor Grading	Assess disease characteristics in patients with intention for treatment with elacestrant: Tumor Grading at initial diagnosis and inclusion	Baseline
Patients and disease characteristics: HR and HER2 status	Assess disease characteristics in patients with intention for treatment with elacestrant: HR status and HER2 status at initial diagnosis and at inclusion	Baseline
Patients and disease characteristics: Prior adjuvant chemotherapy	Assess disease characteristics in patients with intention for treatment with elacestrant: Prior adjuvant chemotherapy	Baseline
Patients and disease characteristics: Prior adjuvant endocrine therapy	Assess disease characteristics in patients with intention for treatment with elacestrant: Prior adjuvant endocrine therapy	Baseline
Patients and disease characteristics: prior CDKi/endocrine therapy in the palliative setting	Assess disease characteristics in patients with intention for treatment with elacestrant: Type and duration of prior CDKi/endocrine therapy in the palliative setting (descriptive statistics, categorical ≤6 months / >6 months; ≤12 months / >12 months)	Baseline
Patients and disease characteristics: Disease site	Assess disease characteristics in patients with intention for treatment with elacestrant: Disease site (bone-only / visceral / non-visceral (not bone-only)) at inclusion	At time of enrollment
Patients and disease characteristics: concomitant diseases	Assess disease characteristics in patients with intention for treatment with elacestrant: concomitant diseases	Baseline
Use of concomitant medication	Assess the use of concomitant medication during treatment with elacestrant.	max. 24 months; from the patient-specific study start to end of study (during elacestrant treatment)
Frequency of first subsequent systemic antineoplastic therapy for ESR1wt patients and ESR1mut patients without elacestrant treatment	Assess second-line treatments for all patients by ESR1 status (Frequency of first subsequent systemic antineoplastic therapy for ESR1wt patients and ESR1mut patients without elacestrant treatment (refers to first treatment received starting from second line)	max. 24 months; at patient patient-specific start of treatment
Details on treatment with elacestrant: reason for end of treatment	Assess reason for end of treatment (treatment with elacestrant)	max. 24 months; from the patient-specific study start to end of study (during elacestrant treatment)
Details on treatment with elacestrant: dose intensity	Assess dose intensity (treatment with elacestrant) as prescribed by the treating physician	max. 24 months; from the patient-specific study start to end of study (during elacestrant treatment)
Details on treatment with elacestrant: frequency and type of dose modification	Assess Frequency and type of dose modifications (dose reductions, interruptions) compared to SmPC of elacestrant.	max. 24 months; from the patient-specific study start to end of study (during elacestrant treatment)
Details on treatment with elacestrant: reasons for dose modifications and interruptions	Assess reasons for dose modifications and interruptions (elacestrant treatment)	max. 24 months; from the patient-specific study start to end of study (during elacestrant treatment)
Treatments following elacestrant therapy: Type of first subsequent systemic antineoplastic therapy	Details on treatments following elacestrant therapy (Type of first subsequent systemic antineoplastic therapy)	max. 24 months; from the patient-specific end of elacestrant treatment until end of study
Treatments following elacestrant therapy: Frequency of first subsequent systemic antineoplastic therapy	Details on treatments following elacestrant therapy:Frequency of first subsequent systemic antineoplastic therapy for ESR1mut patients (refers to first treatment received after Elacestrant so starting from third line)	max. 24 months; from the patient-specific end of elacestrant treatment until end of study

Collaborators and Investigators

• Sponsor: iOMEDICO AG
• Collaborators: Berlin Chemie AG
• Investigators: Principal Investigator: Thomas Decker, Professor, Gemeinschaftspraxis für Hämatologie und Onkologie GbR Ravensburg; Principal Investigator: Michael Patrick Lux, Professor, St. Louise Frauen- und Kinderklinik Paderborn

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): July 1, 2029

Study Registration Dates

• First Submitted: December 2, 2025
• First Submitted That Met QC Criteria: April 29, 2026
• First Posted (Actual): May 4, 2026

Study Record Updates

• Last Update Posted (Actual): May 4, 2026
• Last Update Submitted That Met QC Criteria: April 29, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Quality of life; advanced breast cancer; Elacestrant; ESR1 Mutation; Orserdu
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; Health Services Administration; Health Care Quality, Access, and Evaluation; Quality of Health Care; Quality Indicators, Health Care; Standard of Care; elacestrant
• Other Study ID Numbers: IOM-090506

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO