Elacestrant Monotherapy in ER+/HER2- Advanced Breast Cancer with ESR1 Mutation (Japanese Participants)

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a multicenter, open-label Phase 2 bridging study evaluating the efficacy and safety of elacestrant as a single agent in Japanese post-menopausal women and men with ESR1-mutant, ER+/HER2- advanced or metastatic breast cancer. Participants must have progressed on or afterCDK4/6 inhibitor therapy in combination with fulvestrant or an aromatase inhibitor. The trial uses Guardant360 to confirm ESR1 mutation status before enrollment and will enroll patients who have limited prior lines of endocrine therapy. Lead sponsor is Stemline Therapeutics, with participating sites in Chiba and Fukuoka, Japan. Primary goals focus on response and safety in this specific genetic and geographic subset.

Why it matters

Who can join: the full rules

Key Inclusion Criteria:

* Must have a histologically or cytologically 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
* Female participants must be post-menopausal (as defined by the protocol)
* Must have ER+ and HER2- tumor status confirmed per local laboratory testing
* Participants must be ESR1-mutant positive determined via testing with the Guardant360 Companion Diagnostic panel test prior to enrollment
* Must have disease progression during or within 28 days of completion of prior treatment with a CDK4/6 inhibitor in combination with either fulvestrant or an aromatase inhibitor (this counts as a line of prior endocrine therapy) for metastatic breast cancer

Key Exclusion Criteria:

* Prior treatment with: elacestrant or investigational or approved selective estrogen receptor degrader or ER antagonist; antibody-drug conjugate therapy for advanced/metastatic breast cancer; anti-cancer or investigational drug treatment
* Radiation therapy within 14 days (28 days for brain lesions) before the first dose of study drug
* Intact uterus with a history of endometrial intraepithelial neoplasia (atypical endometrial hyperplasia or higher-grade lesion)
* Diagnosis of any other malignancy within 5 years before enrollment, except for adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or second primary breast cancer

Note: Other protocol-defined inclusion/exclusion criteria may apply.

Where it's running

• Chiba Cancer Center
  Chiba, Japan Recruiting
• Kyushu University Hospital
  Fukuoka, Japan Recruiting
• National Hospital Organization - Kyushu Medical Center
  Fukuoka, Japan Recruiting
• Kansai Medical University Hospital
  Hirakata, Japan Recruiting
• Hiroshima University Hospital
  Hiroshima, Japan Recruiting
• Saitama Cancer Center
  Ina, Japan Recruiting

Study contacts

• Study coordinator: Stemline Trials
• Email: clinicaltrials@menarinistemline.com
• Phone: 1-877-332-7961

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.