96 Elacestrant Real-World Progression-Free Survival of Adult Patients With ER+/HER2–, Advanced Breast Cancer: A Retrospective Analysis Using Insurance Claims in the United States

Publication
Article
Miami Breast Cancer Conference® Abstracts Supplement42nd Annual Miami Breast Cancer Conference® - Abstracts
Volume 39
Issue 4
Pages: 39-40

96 Elacestrant Real-World Progression-Free Survival of Adult Patients With ER+/HER2–, Advanced Breast Cancer: A Retrospective Analysis Using Insurance Claims in the United States

96 Elacestrant Real-World Progression-Free Survival of Adult Patients With ER+/HER2–, Advanced Breast Cancer: A Retrospective Analysis Using Insurance Claims in the United States

Background

Endocrine therapy (ET) plus CDK4/6 inhibitor (CDK4/6i) is the standard-of-care (SOC) for first-line estrogen receptor–positive/HER2-negative (ER+/HER2–) advanced or metastatic breast cancer. Sequential ET monotherapy or combinations are used second line post-ET plus CDK4/6i. Combination regimens in second-line or late metastatic breast cancer can be associated with significant toxicities and high discontinuation rates. ESR1 mutations, a type of acquired resistance, eventually emerge in up to 50% of patients after first-line treatment for ER+/HER2– metastatic breast cancer. In the phase 3 EMERALD trial (NCT03778931), patients with ESR1-mutated tumors had a 45% reduction in risk of progression or death with elacestrant vs SOC ET (median progression-free survival [PFS] 3.8 months vs 1.9 months; HR, 0.55; 95% CI, 0.39-0.77; P = .0005). In patients with 12 months or more prior ET plus CDK4/6i, the median PFS with elacestrant was 8.6 months vs 1.9 months with SOC ET (HR, 0.41; 95% CI, 0.26-0.63). Elacestrant was FDA-approved in January 2023 for the treatment of postmenopausal ER+/HER2– ESR1-mutated metastatic breast cancer with progression after at least one line of ET. Sufficient time has passed since approval to characterize the real-world use of elacestrant in the current treatment landscape. This study aims to describe the real-world PFS of elacestrant overall and in patients with no prior exposure to fulvestrant, only 1 to 2 lines of ET, 3 or more lines of ET, and/or visceral metastases.

Materials and Methods

Adults with diagnosed ER+/HER2– metastatic breast cancer who initiated elacestrant in a real-world setting between January 2023 and May 2024 were identified in the Komodo Research Database. Demographic information described at index date (time of first administration of elacestrant) included metastatic sites identified during the 6-month baseline period prior to index date and prior metastatic breast cancer treatments. Real-world PFS was defined as time from index date until earliest outcome (start of next line of metastatic breast cancer therapy to progression or death). Patients were censored at first occurrence of end of data availability or end of health plan enrollment.

Results

A total of 276 patients treated were evaluated (median age 63 years, 86% visceral metastases, 90% prior CDK4/6i, 61% prior fulvestrant). Real-world PFS was prolonged with elacestrant in patients with prior fulvestrant and in the overall population in all subgroups (Table).

Table. Real-World Median Progression-Free Survival

Table. Real-World Median Progression-Free Survival

Conclusion

In a real-world setting, elacestrant showed a consistent real-world PFS benefit among all patients with ER+/HER2– metastatic breast cancer and across clinically relevant subgroups. The real-world PFS with elacestrant exceeded the overall median PFS in EMERALD and is longer when patients are treated in earlier lines.

Articles in this issue

13 Preliminary Analysis of Change During Treatment of Financial Toxicity and Quality of Life in Breast Cancer Patients
13 Preliminary Analysis of Change During Treatment of Financial Toxicity and Quality of Life in Breast Cancer Patients
15 Utilizing Circulating Tumor Cells to Guide HER2-Directed Therapy in IHC/FISH-Negative HER2+ Metastatic Breast Cancer
15 Utilizing Circulating Tumor Cells to Guide HER2-Directed Therapy in IHC/FISH-Negative HER2+ Metastatic Breast Cancer
16 A Miami Hospital’s Infrastructure to Help Decrease Late-Stage Breast Cancer Diagnosis and Improve Health Equity
16 A Miami Hospital’s Infrastructure to Help Decrease Late-Stage Breast Cancer Diagnosis and Improve Health Equity
17 Salmonella and the Breast: A Literature Review of Salmonella-Induced Breast Abscesses
17 Salmonella and the Breast: A Literature Review of Salmonella-Induced Breast Abscesses
18 Tolerability of First-Line Treatment With Ribociclib for Metastatic Breast Cancer Using 2 Large US Data Sources
18 Tolerability of First-Line Treatment With Ribociclib for Metastatic Breast Cancer Using 2 Large US Data Sources
20 Impact of Ribociclib Dose Reduction on Efficacy in Patients With Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast
20 Impact of Ribociclib Dose Reduction on Efficacy in Patients With Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast
21 Distant Disease-Free Survival Across Key Subgroups From the Phase 3 NATALEE Trial of Ribociclib Plus a Nonsteroidal Aromatase Inhibitor in Patients With HR+/HER2− Early Breast Cancer
21 Distant Disease-Free Survival Across Key Subgroups From the Phase 3 NATALEE Trial of Ribociclib Plus a Nonsteroidal Aromatase Inhibitor in Patients With HR+/HER2− Early Breast Cancer
22 Efficacy and Safety of Ribociclib + Nonsteroidal Aromatase Inhibitor in Younger Patients With HR+/HER2− Early Breast Cancer in NATALEE
22 Efficacy and Safety of Ribociclib + Nonsteroidal Aromatase Inhibitor in Younger Patients With HR+/HER2− Early Breast Cancer in NATALEE
23 Clinical Outcomes in Patients With HR+/HER2− Early Breast Cancer By Prior Systemic Treatment: A Subgroup Analysis of the NATALEE Trial
23 Clinical Outcomes in Patients With HR+/HER2− Early Breast Cancer By Prior Systemic Treatment: A Subgroup Analysis of the NATALEE Trial
TPS 24 Phase Ib Dose-Finding Study of [177Lu]Lu-NeoB + Ribociclib + Fulvestrant in Patients With ER+/HER2− Advanced Breast Cancer With GRPR Expression With Early Relapse FromAdjuvant Endocrine Therapy or Progression on ET + CDK4/6i for ABC
TPS 24 Phase Ib Dose-Finding Study of [177Lu]Lu-NeoB + Ribociclib + Fulvestrant in Patients With ER+/HER2− Advanced Breast Cancer With GRPR Expression With Early Relapse FromAdjuvant Endocrine Therapy or Progression on ET + CDK4/6i for ABC
TPS 25 Phase 1/2 Study of the Novel Radioligand Therapy [177Lu]Lu-NeoB Plus Capecitabine in Patients With ER+/HER2− Advanced Breast Cancer (ABC) With GRPR Expression After Progression on Prior Endocrine Therapy Plus a CDK4/6 Inhibitor for ABC
TPS 25 Phase 1/2 Study of the Novel Radioligand Therapy [177Lu]Lu-NeoB Plus Capecitabine in Patients With ER+/HER2− Advanced Breast Cancer (ABC) With GRPR Expression After Progression on Prior Endocrine Therapy Plus a CDK4/6 Inhibitor for ABC
26 Risk of Recurrence in Real-World NATALEE- and monarchE-Eligible Populations of Patients With HR+/HER2− Early Breast Cancer in an Electronic Health Record-Derived Database
26 Risk of Recurrence in Real-World NATALEE- and monarchE-Eligible Populations of Patients With HR+/HER2− Early Breast Cancer in an Electronic Health Record-Derived Database
27 Elacestrant vs Standard of Care in ER+, HER2- Advanced or Metastatic Breast Cancer With ESR1-Mutated Tumors: ESR1 Allelic Frequencies and Clinical Activity From the Phase 3 EMERALD Trial
27 Elacestrant vs Standard of Care in ER+, HER2- Advanced or Metastatic Breast Cancer With ESR1-Mutated Tumors: ESR1 Allelic Frequencies and Clinical Activity From the Phase 3 EMERALD Trial
TPS 28 ELEGANT: Elacestrant VS Standard Endocrine Therapy in Women and Men With Node-Positive, Estrogen Receptor-Positive, HER2-Negative, Early Breast Cancer With High Risk of Recurrence in a Global, Multicenter, Randomized, Open-Label Phase 3 Study
TPS 28 ELEGANT: Elacestrant VS Standard Endocrine Therapy in Women and Men With Node-Positive, Estrogen Receptor-Positive, HER2-Negative, Early Breast Cancer With High Risk of Recurrence in a Global, Multicenter, Randomized, Open-Label Phase 3 Study
29 A Real-World Exploratory Analysis to Identify Disparities in Breast Cancer Tumor Biopsy Practice at Community Oncology Clinics in the United States
29 A Real-World Exploratory Analysis to Identify Disparities in Breast Cancer Tumor Biopsy Practice at Community Oncology Clinics in the United States

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