Biomarkers to Detect Endocrine Therapy Resistance

April 6, 2026 updated by: University of Wisconsin, Madison

Integrating Minimally Invasive Biomarkers of Estrogen Signaling to Detect Endocrine Therapy Resistance in Metastatic Invasive Lobular Breast Cancer

This pilot observational study is being done to identify possible biomarkers of response to endocrine therapy in patients with ER/PR+ metastatic lobular breast cancer (LBC) starting new endocrine therapy. 18F-fluorofuranylnorprogesterone Positron Emission Tomography/Computed Tomography (FFNP-PET/CT) and liquid biopsies will be performed at baseline and after 4 weeks of treatment. Baseline levels and dynamic on-treatment changes in estrogen signaling as measured by FFNP-PET/CT and circulating tumor cell (CTC) liquid biopsy will be correlated with clinical response to endocrine therapy and progression-free survival in the above cohort of patients.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

8

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Wisconsin
      • Madison, Wisconsin, United States, 53792
        • Recruiting
        • UW Carbone Cancer Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Willing to provide informed consent
  2. Individuals at least 18 years of age
  3. Have biopsy-proven ER/PR-positive (defined as ER ≥1 percent and PR ≥1 percent by IHC) and HER2-negative advanced or metastatic LBC starting new standard of care endocrine therapy
  4. Adequate organ function as indicated by standard laboratory tests (CBC, liver function tests or CMP) allowing for systemic breast cancer treatment per treating oncologist
  5. Patients with evaluable bone-only disease that is lytic or mixed lytic-sclerotic are eligible
  6. Willing to comply with all study procedures and be available for the duration of the study
  7. Disease may be measurable by RECIST 1.1 criteria or non-measurable. Lesion size must be at least 1cm. If only bone lesions present, they should be lytic or mixed lytic-sclerotic. If only liver lesions present, patient is not eligible.

Exclusion Criteria:

  1. Patients with active brain metastases
  2. Patients with liver-only disease are not eligible due to high background liver activity related to the radiopharmaceutical's hepatobiliary route of elimination
  3. Unable to lie flat during or tolerate PET/CT
  4. Patients with a history of allergic reaction attributable to compounds of similar chemical or biologic composition to FFNP
  5. Presence of liver failure as judged by patient's treating physician
  6. Individuals who are pregnant, lactating, or planning on becoming pregnant during the study
  7. Not suitable for study participation due to other reasons at the discretion of the investigators
  8. Patients with progesterone-receptor negative disease defined as PR <1 percent by IHC

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Participants with ER/PR+ metastatic lobular breast cancer (LBC)
Drug: 18F-fluorofuranylnorprogesterone
The dose of the investigational imaging agent, FFNP, is approximately 7 millicurie (mCi) (259 megabecquerels (MBq)), IV slow infusion over approximately two minutes followed by saline flush.
Other Names:
  • FFNP
Device: Positron Emission Tomography/Computed Tomography
FFNP drug in combination with PET/CT scans to image participant
Other Names:
  • PET/CT
Device: Liquid Biopsy
20ml of whole blood will be collected into two Ethylenediaminetetraacetic acid (EDTA) tubes at each timepoint, CTCs are isolated using the microfluidic Versatile Exclusion-based Rare Sample Analysis (VERSA) platform that integrates CTC capture with RNA extraction on a single chip using Exclusion-Based Sample Preparation (ESP) technology
Other Names:
  • Circulating Tumor Cells (CTC)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants who have decreased FFNP uptake on PET/CT in response to endocrine therapy
Time Frame: baseline, 4 weeks
baseline, 4 weeks
Number of Participants who have decrease in circulating tumor cell estrogen signaling in response to endocrine therapy
Time Frame: baseline, 4 weeks
Baseline level and on-treatment CTC ESR1 and estrogen regulated gene expression will be evaluated as well as endocrine-resistance associated mutations including ESR1 (though rare in this patient population) and PGR.
baseline, 4 weeks
Number of Participants who have a decrease in concentration of Circulating Tumor DNA in response to endocrine therapy
Time Frame: baseline, 4 weeks
baseline, 4 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Progression Free Survival (PFS) for 6 months
Time Frame: up to 6 months
up to 6 months
Correlation coefficients
Time Frame: up to 6 months
Correlate baseline levels and dynamic on treatment changes in estrogen signaling as measured by FFNP-PET/CT and CTC liquid biopsy with clinical response to endocrine therapy and progression-free survival in patients with ER/PR+ metastatic LBC.
up to 6 months
Adverse Events within 24 hours of FFNP infusion
Time Frame: a 24 hour period up to 7 days pre-treatment, a 24 hour period 4 weeks after the first infusion
a 24 hour period up to 7 days pre-treatment, a 24 hour period 4 weeks after the first infusion

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Wisconsin, Madison

Investigators

  • Principal Investigator: Marina Sharifi, MD, PHD, UW Carbone Cancer Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 30, 2024

Primary Completion (Estimated)

August 1, 2026

Study Completion (Estimated)

August 1, 2026

Study Registration Dates

First Submitted

September 19, 2023

First Submitted That Met QC Criteria

September 27, 2023

First Posted (Actual)

October 5, 2023

Study Record Updates

Last Update Posted (Actual)

April 13, 2026

Last Update Submitted That Met QC Criteria

April 6, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2023-1103
  • SMPH/MEDICINE/HEM-ONC (Other Identifier: UW Madison)
  • UW23076 (Other Identifier: OnCore ID)
  • Protocol Version 10/2/2023 (Other Identifier: UW Madison)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data from this study may be requested from other researchers up to 7 years after the completion of the primary endpoint by contacting the University of Wisconsin Carbone Cancer Center (UWCCC)

IPD Sharing Time Frame

up to 7 years after the completion of the primary endpoint

IPD Sharing Access Criteria

UWCCC Cancer Connect: clinicaltrials@cancer.wisc.edu

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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