Lasofoxifene and Abemaciclib for ER+/HER2- Metastatic Breast Cancer with ESR1 Mutation

This study is comparing two treatment combinations for locally advanced or metastatic estrogen receptor positive (ER+) / human epidermal growth factor 2 negative (HER2-) breast cancer with an ESR1 mutation. You might be eligible if you are a pre- or postmenopausal woman or man whose cancer has progressed after previous treatment with an AI (aromatase inhibitor) combined with palbociclib or ribociclib. The study is testing if a combination of lasofoxifene and abemaciclib is more effective than fulvestrant and abemaciclib. The main goal is to see how long people live without their cancer growing or spreading (progression-free survival). This study plans to enroll about 600 participants, but its current status is unclear.

Study design
This interventional study is comparing two different drug combinations. It aims to enroll 600 participants.
What's involved
Participants will receive either oral lasofoxifene plus oral abemaciclib, or intramuscular fulvestrant plus oral abemaciclib.
Compensation
Not stated in the trial record.
Follow-up
Progression-free survival will be measured for approximately 3 years.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05696626

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

Recruiting
PHASE3Ages 18+InterventionalTreatment
LeonaBio
~600 participants
Updated 2026-06-22 on ClinicalTrials.gov
What's tested:Lasofoxifene in combination with abemaciclibFulvestrant in combination with abemaciclib

At a glance

Recruiting sites
192 of 224 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Progression free survival (PFS)
Measured over Within approximately 3 years
Metastatic Breast Cancer
224 sites across 41 states
China77
Italy14
France13
Spain13
Israel10
United Kingdom9
Poland8
Romania7
Simon Daggett - Senior Vice President, Clinical Operations
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  • Progression free survival (PFS)Within approximately 3 years

    PFS is defined as the time from the date of randomization \[Visit 0 (Day 1)\] to the earliest date of first documented progression per RECIST 1.1 as determined by BICR or death due to any cause.