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Study identifier: NCT05696626 Synced from ClinicalTrials.gov · July 30, 2026
● Recruiting

Evaluation of Lasofoxifene Combined With Abemaciclib Compared With Fulvestrant Combined With Abemaciclib in Locally Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation

Condition: Metastatic Breast Cancer  ·  Sponsor: LeonaBio

PhasePhase 3
Planned participants600
Who can joinAll sexes, 18 Years to no upper limit
Healthy volunteersNo

About this study

The goal of this clinical trial is to assess the efficacy, safety and tolerability of the combination of lasofoxifene and abemaciclib compared to fulvestrant and abemaciclib for the treatment of pre- and postmenopausal women and men who have previously received ribociclib or palbociclib-based treatment and have locally advanced or metastatic estrogen receptor positive (ER+)/human epidermal growth factor 2 negative (HER2-) breast cancer with an estrogen receptor 1 (ESR1) mutation. The main question the study aims to answer is: • To compare the efficacy of the combination of lasofoxifene and abemaciclib with that of fulvestrant and abemaciclib Participants will receive either receive 5 mg/d of oral lasofoxifene plus oral abemaciclib 150 mg twice a day or the combination of fulvestrant 500 mg intramuscular (IM) on Days 1, 15, and 29 and then once monthly thereafter plus oral abemaciclib 150 mg twice a day.

This description comes directly from the study's public registry record.

Talk to the study team

Simon Daggett - Senior Vice President, Clinical Operations  ·  (909) 374-3793  ·  clinicaltrials@leonabio.com

Always discuss trial participation with your own doctor first.

Locations (224)

Mayo Clinic - ScottsdaleScottsdale, Arizona, United StatesRecruiting
University of Arizona - Cancer CenterTucson, Arizona, United StatesRecruiting
Providence Medical Foundation - Santa Rosa, CASanta Rosa, California, United StatesRecruiting
Mayo Clinic - JacksonvilleJacksonville, Florida, United StatesRecruiting
Miami Cancer InstituteMiami, Florida, United StatesRecruiting
Miami Cancer Institute PlantationPlantation, Florida, United StatesRecruiting
Emory University School of MedicineAtlanta, Georgia, United StatesRecruiting
Norton Cancer InstituteLouisville, Kentucky, United StatesRecruiting
Johns Hopkins Kimmel Cancer CenterBaltimore, Maryland, United StatesRecruiting
Massachusetts General HospitalBoston, Massachusetts, United StatesRecruiting
Dana-Farber Cancer InstituteBoston, Massachusetts, United StatesRecruiting
Beth Israel Deaconess Medical CenterBoston, Massachusetts, United StatesRecruiting

+ 212 more locations — full list on the registry record.

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Source record: clinicaltrials.gov/study/NCT05696626