Active, not recruitingPhase IIFemale onlyEN originalBreast cancerHormone receptor positive (HR+)

(Z)-Endoxifen for the Treatment of Premenopausal Women With ER+/HER2- Breast Cancer

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This is not medical advice. AI-assisted translation — inaccuracies may occur. Always verify the original and consult your oncologist before taking any steps.

This trial is no longer recruiting — here are similar active trials

Matched by cancer type/biomarker, currently recruiting.

The purpose of this study is to investigate the efficacy, safety, and tolerability of camizestrant in combination with ribociclib in patients with ER+ HER2- BC who have not received any other systemic treatment for advanced disease. Participants will be treated within the trial until they discontinue the study treatment for any reason.

RecruitingPhase III🇵🇱 PolandBreast cancerHormone receptor positive (HR+)

The primary objective of the study is to measure efficacy of saruparib (AZD5305) plus camizestrant compared with physician's choice CDK4/6i plus ET in patients with BRCA1, BRCA2, or PALB2m, HR-positive, HER2-negative (defined as IHC 0, 1+, 2+/ ISH non-amplified) advanced breast cancer

This study will evaluate the efficacy and safety of the combination of inavolisib plus a cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) and letrozole versus placebo plus a CDK4/6i and letrozole in the first-line setting in participants with endocrine-sensitive PIK3CA-mutated hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-), advanced breast cancer (ABC).

About the trial

This open-label research study is studying (Z)-endoxifen as a possible treatment for pre-menopausal women with ER+/HER2- breast cancer. (Z)-endoxifen belongs to a group of drugs called selective estrogen receptor modulators or "SERM", which help block estrogen from attaching to cancer cells. This study has two parts: a pharmacokinetic part and a treatment part. The PK part (how the body processes the drug) will enroll about 18 participants. All participants will take (Z)-endoxifen capsules daily. Twelve participants will be randomly assigned (50/50 chance) to take (Z)-endoxifen alone or (Z)-endoxifen with a monthly injection of goserelin a drug that temporarily stops the ovaries from making estrogen. This part will help determine the best dose of (Z)-endoxifen by measuring the drug levels in the blood and how long the body takes to remove it. The Treatment Cohort has been simplified to a single study arm (Z)-endoxifen + goserelin. Up to 20 participants will be enrolled that have a baseline Ki-67 ≤ 10% and 45 participants will be enrolled that have a baseline Ki-67\>10%. A key goal of the study is to see if (Z)-endoxifen can slow down or stop tumor growth as measured by a reduction in Ki-67 levels. Tumor tissue samples will be taken by breast biopsy after about 4 weeks of treatment to check levels of this biomarker. If the tumor shows signs of response, participants can continue treatment for up to 24 weeks or until they have surgery. Study participation is up to 6 months (24 weeks of treatment) followed by surgery and a one-month follow up visit.

Original English text from ClinicalTrials.gov

Who can (and can't) join

✓ Qualifies

  • Kobieta (urodzenie biologiczne jako kobieta)
  • Wiek 18 lat lub więcej
  • Nie w ciąży, nie karmiąca piersią i nie planująca ciąży w następnym roku; zgodna na używanie antykoncepcji przez 9 miesięcy po ostatniej dawce leku
  • Stosowanie co najmniej jednej niezawodnej metody antykoncepcji niezawierającej hormonów przez cały czas badania
  • W wieku przed menopauzą - menstruująca lub ze stężeniem estradiolu we właściwym zakresie
  • Potwierdzony nowotwór piersi dodatni do receptora estradiolu (≥67% lub wynik Allred 6-8)
  • Stan ogólny zdrowia 0-2 wg skali ECOG (może być lekko ograniczona aktywność)
  • Guz T2 lub T3 (średni lub duży) bez przerzutów odległych, z przerzutami maksymalnie w węzłach chłonnych pacjorowych

✗ Disqualifies

  • Nowotwór w obu piersiach jednocześnie lub zapalny nowotwór piersi
  • Wcześniejsza diagnoza lub leczenie raka piersi, lub inny aktywny nowotwór w ostatnich 2 latach (z wyjątkiem leczonych zmian przedrakowych)

Simplified criteria — AI translation

Trial details

Minimum age
18 Years
Last updated (source)
July 8, 2026
Sex
Female only

Therapies / drugs in trial

Locations (14)

Mayo Clinic Arizona

Phoenix, United States

University of Arizona

Tucson, United States

California Research Institute

Los Angeles, United States

Mayo Clinic Florida

Jacksonville, United States

Northwestern University

Chicago, United States

St. Elizabeth Healthcare

Edgewood, United States

Henry Ford Cancer Institute

Detroit, United States

Mayo Clinic Rochester

Rochester, United States

Washington University School of Medicine

St Louis, United States

Avera Cancer Institute

Sioux Falls, United States

Vanderbilt Ingram Cancer Center

Nashville, United States

Baylor University

Houston, United States

Bon Secours Cancer Institute

Midlothian, United States

Fred Hutchinson Cancer Center

Seattle, United States

Share this trial

Data from ClinicalTrials.gov. AI-assisted translation, last sync: 7/1/2026.

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