Recruiting
Phase 2

Endocrine Therapy Resistance

Sponsor:

University of Wisconsin, Madison

Code:

NCT06067503

Conditions

Metastatic Cancer

Breast Cancer

Lobular Breast Carcinoma

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

18F-fluorofuranylnorprogesterone

Liquid Biopsy

Positron Emission Tomography/Computed Tomography

Study Details

Brief summary:

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.

Conditions

Metastatic Cancer

Breast Cancer

Lobular Breast Carcinoma

Study ID

NCT06067503

Start date

Apr 30, 2024

Status verified date

Aug, 2026

Completion date

Dec, 2026

Anticipated

Primary completion date

Dec, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

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 Design

Enrollment

8 participants

Anticipated

Intervention Model

Single group

Primary purpose

Diagnostic

Interventions and Outcome Measures

Arms

experimental: Participants with ER/PR+ metastatic lobular breast cancer (LBC)

Interventions

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.

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

Positron Emission Tomography/Computed Tomography

FFNP drug in combination with PET/CT scans to image participant

Primary outcome measure

  • Number of Participants who have decreased FFNP uptake on PET/CT in response to endocrine therapy [ Time Frame: 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 ]
  • Number of Participants who have a decrease in concentration of Circulating Tumor DNA in response to endocrine therapy [ Time Frame: baseline, 4 weeks ]

Central Contacts and Locations

Central contacts

Cancer Connect

800-622-8922clinicaltrials@cancer.wisc.edu

Locations

UW Carbone Cancer Center

Recruiting

Madison, Wisconsin, United States, 53792

More Information

Sponsor

University of Wisconsin, Madison

Last update posted

Aug 25, 2026

Last verified

Aug, 2026

Keywords

  • Endocrine Therapy Resistance
  • circulating tumor cell
  • liquid biopsy

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Wisconsin, Madison on 2026-08-25.