RecruitingEarly Phase 1NCT04174352

FES Imaging to Optimize Tamoxifen for Metastatic Breast Cancer

A Pilot Study of FES Imaging to Optimize Tamoxifen Dose for Metastatic Breast Cancer Patients With ESR1 Mutations

Sponsor

University of Wisconsin, Madison

Enrollment

12 participants

Start Date

Oct 20, 2020

Study Type

INTERVENTIONAL

Conditions

ER+ Breast Cancer ESR1 Gene Mutation

Summary

Despite broad advancements in endocrine therapy for ERα+ breast cancer, resistance ultimately develops. A common driver of resistance are known ESR1 mutations that lead to constitutively active receptor signaling and transcriptional regulation that is always "turned on" despite the absence of estrogen. Patients with ESR1 mutations are expected to have decreased binding affinity for tamoxifen and thus may be underdosed on standard therapy. \[18F\]-fluoroestradiol Positron Emission Tomography/Computed tomography (FES-PET/CT) imaging is a novel functional imaging technique that can non-invasively measure ERα expression and inhibition in metastatic ERα+ breast cancer. The proposed a pilot study uses FES-PET/CT imaging to measure ERα blockade to determine the optimal dose of tamoxifen in patients with ESR1 mutations.

Eligibility

Min Age: 19 Years

Plain Language Summary

Simplified for easier understanding

This study is using a special PET scan (FES-PET) to see how well hormone receptors in breast cancer are functioning, in order to help decide whether tamoxifen is a good treatment choice for patients with metastatic breast cancer and a specific gene mutation (ESR1). **You may be eligible if...** - You have metastatic or inoperable breast cancer - Your tumor is estrogen receptor-positive (ER+ ≥ 10%) - You have an ESR1 mutation identified through a certified lab test - Your cancer is HER2-negative - You have measurable disease on imaging **You may NOT be eligible if...** - Your cancer is HER2-positive - You are unable to have a PET scan - You have had prior tamoxifen therapy for metastatic disease - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.

This summary was AI-generated to explain the trial in plain language. It is not medical advice. Always discuss eligibility with your doctor before enrolling in a clinical trial.

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Interventions

DRUGTamoxifen

estrogen modulator

DIAGNOSTIC_TESTFES PET/CT

Radiolabeled estrogen \[18F\]-fluoroestradiol (FES) in combination with Positron Emission Tomography / Computed Tomography is a molecular imaging technique for measuring pharmacodynamic effects of endocrine therapy. The injected dose of 18F-FES will be 6 mCi (185 MBq) ± 20% with a specific activity greater than 170 Ci/mmol at the time of injection for an activity dose of 6 mCi. Participant will receive baseline imaging and repeat imaging after 3-4 weeks to evaluate for FES blockade as assigned dose level.