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Phase 3 Trial of Elacestrant vs. Standard of Care for the Treatment of Patients With ER+ / HER2- Advanced Breast Cancer

Trial Status: Active

This Phase 3 clinical study compares the efficacy and safety of elacestrant to the standard of care (SoC) options of fulvestrant or an aromatase inhibitor (AI) in women and men with breast cancer whose disease has advanced on at least one endocrine therapy including a CDK4 / 6 inhibitor in combination with fulvestrant or an aromatase inhibitor (AI) .

Inclusion Criteria

  • Subjects with proven diagnosis of adenocarcinoma of the breast with evidence of either locally advanced disease not amenable to resection or radiation therapy with curative intent or metastatic disease not amenable to curative therapy.
  • Subjects must be appropriate candidates for endocrine monotherapy
  • Subjects must have measurable disease or, nonmeasurable (evaluable) bone-only disease
  • Female or male subjects age ≥ 18 years; female subjects must be postmenopausal women and male subjects must not allow pregnancy with their sperm (abstain, do not donate sperm, etc).
  • Subjects must have ER+/HER2-tumor status
  • Subjects must have previously received at least one and no more than two lines of endocrine therapy for advanced/metastatic breast cancer and meet additional previous treatment criteria.
  • Subjects must have received prior treatment with a CDK4/6 inhibitor in combination with either fulvestrant or an aromatase inhibitor (AI).
  • Subjects may have received no more than one line of chemotherapy in the advanced/metastatic setting.
  • Subjects must have ctDNA ESR1-mut or ESR1-WT status as determined by central testing before subject is randomized.

Exclusion Criteria

  • Prior treatment with elacestrant, GDC-0810, GDC-0927, GDC-9545, LSZ102, AZD9496, bazedoxifene, or other investigational SERD or investigational ER antagonist.
  • Prior anticancer or investigational drug treatment within the following windows:
  • Fulvestrant treatment < 28 days before first dose of study drug
  • Any endocrine therapy < 14 days before first dose of study drug (with the exception of GnRH agonist therapy in male subjects)
  • Chemotherapy < 21 days before first dose of study drug
  • Any investigational anti-cancer drug therapy < 28 days or five half-lives (whichever is shorter) before the first dose of study drug. Enrollment of subjects whose most recent therapy was an investigational agent should be discussed with the Sponsor
  • Presence of symptomatic visceral disease as defined in protocol.


Los Angeles
UCLA / Jonsson Comprehensive Cancer Center
Contact: Sarah Rosales
Phone: 310-794-7686
USC / Norris Comprehensive Cancer Center
Status: ACTIVE
Contact: Grace M Facio
Phone: 323-409-7027ext3511
University of California Davis Comprehensive Cancer Center
Status: ACTIVE


University of Colorado Hospital
Status: ACTIVE


Moffitt Cancer Center
Status: ACTIVE


Kansas City
University of Kansas Cancer Center
Status: ACTIVE
Contact: Sherri Miller
Phone: 913-945-7658


Massachusetts General Hospital Cancer Center
Status: ACTIVE
Newton-Wellesley Hospital
Status: ACTIVE


Wayne State University / Karmanos Cancer Institute
Status: ACTIVE


Mayo Clinic in Rochester
Status: ACTIVE

New Mexico

University of New Mexico Cancer Center
Status: ACTIVE

New York

Montefiore Medical Center-Weiler Hospital
Status: ACTIVE
New York
Laura and Isaac Perlmutter Cancer Center at NYU Langone
Status: ACTIVE


Case Comprehensive Cancer Center
Status: ACTIVE


OHSU Knight Cancer Institute
Status: ACTIVE


Thomas Jefferson University Hospital
University of Pittsburgh Cancer Institute (UPCI)
Status: ACTIVE

South Carolina

Medical University of South Carolina


San Antonio
Cancer Therapy and Research Center at The UT Health Science Center at San Antonio
Status: ACTIVE
Contact: Sonia Lisa Creighton
Phone: 210-450-1366


University of Virginia Cancer Center
Status: ACTIVE

This is an international, multicenter, randomized, open-label, active-controlled, event-driven, Phase 3 clinical study comparing the efficacy and safety of elacestrant to the SoC options of fulvestrant or an aromatase inhibitor (AI) in postmenopausal women and in men with advanced or metastatic ER+/HER2- breast cancer, either in subjects with tumors that harbor mutations in the ligand binding domain (LBD) of the estrogen receptor 1 (ESR1) gene (ESR1-mut subjects) or in all subjects regardless of ESR1 status (ESR1-mut and ESR1 wild type [ESR1-WT]) and whose disease has relapsed or progressed on at least one and no more than two prior lines of endocrine therapy (with documented progression), which must have included prior CDK4/6 inhibitor therapy in combination with fulvestrant or an aromatase inhibitor (AI) and for whom hormonal monotherapy with one of the SoC drugs (fulvestrant, anastrozole, letrozole, exemestane) is an appropriate treatment option.

Trial Phase Phase III

Trial Type Treatment

Lead Organization
Radius Pharmaceuticals, Inc.

  • Primary ID RAD1901-308
  • Secondary IDs NCI-2019-01456
  • ID NCT03778931