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FES Imaging to Optimize Tamoxifen for Metastatic Breast Cancer

NCT04174352 · Status: RECRUITING · Phase: EARLY_PHASE1 · Type: INTERVENTIONAL · Enrollment: 12

Last updated 2025-12-22

No results posted yet for this study

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.

Conditions

  • ERα+ Breast Cancer
  • ESR1 Gene Mutation

Interventions

DRUG

Tamoxifen

estrogen modulator

DIAGNOSTIC_TEST

FES 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.

Sponsors & Collaborators

  • University of Wisconsin, Madison

    lead OTHER

Principal Investigators

  • Kari Wisinski, MD · University of Wisconsin, Madison

Study Design

Allocation
NA
Purpose
TREATMENT
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
19 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2020-10-20
Primary Completion
2026-12-31
Completion
2027-12-31
FDA Drug
Yes

Countries

  • United States

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT04174352 on ClinicalTrials.gov