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RecruitingNCT06067503Updated Aug 25, 2026

Biomarkers to Detect Endocrine Therapy Resistance

A Phase 2 interventional study of 18F-fluorofuranylnorprogesterone and Liquid Biopsy in Metastatic Cancer, Breast Cancer and Lobular Breast Carcinoma, sponsored by University of Wisconsin, Madison. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-25.

Sponsored by University of Wisconsin, Madison · Phase 2, Interventional, and Diagnostic

From the registry’s dates

  • Started Apr 2024; still recruiting 2 years 6 months later.
Phase
Phase 2
Study type
Interventional
Enrollment
8
Allocation
Not applicable
Ages
18 Years and older
Sex
All
01

Study 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.

02

Conditions studied

  • Metastatic Cancer
  • Breast Cancer
  • Lobular Breast Carcinoma

Keywords

  • Endocrine Therapy Resistance
  • circulating tumor cell
  • liquid biopsy
03

In context

Neoplasm Metastasis

4,040 studies on the registry are indexed under Neoplasm Metastasis; 886 are open to participants now.

This study's planned enrollment of 8 is below the median of 50 across 3,268 interventional studies indexed under Neoplasm Metastasis.

Browse Neoplasm Metastasis studies →

Lead sponsor

University of Wisconsin, Madison is the lead sponsor of 1,188 studies on the registry; 181 are open to participants now.

Of its 157 completed or terminated interventional studies of FDA-regulated products, 118 (75%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Willing to provide
  2. Individuals at least 18 years of age
  3. Have -proven ER/PR-positive (defined as ER ≥1 percent and PR ≥1 percent by IHC) and -negative advanced or 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 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

Exclusion Criteria:

  1. Patients with active
  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
Terms in these criteria, in plain language(6)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Biopsy and archival tissue

A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.

Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.

HER2

HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.

In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

RECIST

The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.

“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

05

Study design

Phase
Phase 2
Primary purpose
Diagnostic
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
8 participants (estimated)

Study arms

  • Experimental
    Participants with ER/PR+ metastatic lobular breast cancer (LBC)

    Drug: 18F-fluorofuranylnorprogesterone · Device: Liquid Biopsy · Device: Positron Emission Tomography/Computed Tomography

Interventions

  • Drug18F-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.

    Also known as: FFNP

  • DeviceLiquid 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

    Also known as: Circulating Tumor Cells (CTC)

  • DevicePositron Emission Tomography/Computed Tomography

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

    Also known as: PET/CT

06

What researchers measure

Primary outcomes

  1. Number of Participants who have decreased FFNP uptake on PET/CT in response to endocrine therapy

    Time frame: baseline, 4 weeks

  2. Number of Participants who have decrease in circulating tumor cell estrogen signaling in response to endocrine therapy

    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.

    Time frame: baseline, 4 weeks

  3. Number of Participants who have a decrease in concentration of Circulating Tumor DNA in response to endocrine therapy

    Time frame: baseline, 4 weeks

Secondary outcomes

  1. Progression Free Survival (PFS) for 6 months

    Time frame: up to 6 months

  2. Correlation coefficients

    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.

    Time frame: up to 6 months

  3. 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

07

Study locations

1 of 1 sites recruiting
08

References and documents

Individual participant data

Plan to share: Yes — 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)

Time frame: up to 7 years after the completion of the primary endpoint

Access criteria: UWCCC Cancer Connect: clinicaltrials@cancer.wisc.edu

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Aug 25, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT06067503
Responsible party
Sponsor
First posted
Oct 5, 2023
Start date
Apr 30, 2024
Primary completion
Dec 2026 (estimated)
Completion
Dec 2026 (estimated)
Last update
Aug 25, 2026

Study contacts

Cancer Connect
Contact
clinicaltrials@cancer.wisc.edu
800-622-8922
Marina Sharifi, MD, PHD
principal investigator · UW Carbone Cancer Center

Oversight

FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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