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NCT Number: NCT06067503

Biomarkers to Detect Endocrine Therapy Resistance

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.

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Key information

Conditions

Metastatic Cancer Adenocarcinoma Breast Cancer Breast Diseases Breast Neoplasms Carcinoma Carcinoma, Lobular Lobular Breast Carcinoma Neoplasm Metastasis Neoplasms Neoplasms by Histologic Type Neoplasms by Site Neoplasms, Ductal, Lobular, and Medullary Neoplasms, Glandular and Epithelial Neoplastic Cells, Circulating Neoplastic Processes Pathologic Processes Pathological Conditions, Signs and Symptoms Skin Diseases Skin and Connective Tissue Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

UW Carbone Cancer Center

Madison, Wisconsin, 53792, United States

Location status: Recruiting

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Willing to provide informed consent
  • Individuals at least 18 years of age
  • 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
  • Adequate organ function as indicated by standard laboratory tests (CBC, liver function tests or CMP) allowing for systemic breast cancer treatment per treating oncologist
  • Patients with evaluable bone-only disease that is lytic or mixed lytic-sclerotic are eligible
  • Willing to comply with all study procedures and be available for the duration of the study
  • 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

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

Treatment and study plan

18F-fluorofuranylnorprogesterone

Drug

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

Liquid Biopsy

Device

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)

Positron Emission Tomography/Computed Tomography

Device

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

Other names: PET/CT

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

    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.

  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

    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.

  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

Study contacts

Contact information is provided by the study sponsor or research team.

Cancer Connect

CONTACT

[email protected]

800-622-8922

Sponsors and collaborators

Lead sponsor

University of Wisconsin, Madison

Other

Registry information

Official study title

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

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Oct 5, 2023
Registry last updated
Apr 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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