[18F]FTT Positron Emission Tomography for the Measurement of PARP Tumor Expression in Patients With Metastatic Breast Cancer

[18F]FTT Positron Emission Tomography (PET) in Patients With Metastatic Breast Cancer

This clinical trial studies how well fluorine F 18 fluorthanatrace ([18F]FTT) positron emission tomography (PET) works in imaging patients with breast cancer that has spread from where it first started (primary site) to other places in the body (metastatic) who are receiving standard of care (SOC) poly (ADP-ribose) polymerase (PARP) inhibitors with or without immune checkpoint inhibitors (ICI) to be able to detect clinical response to PARP inhibitor ± ICI treatment. [18F]FTT is a radiotracer that targets and binds to PARP1 which can potentially be used for the imaging of PARP1 expression using PET. Once administered, [18F]FTT targets and binds to PARP1. Upon PET, PARP1-expressing tumor cells can be visualized. PET is an established imaging technique that utilizes small amounts of radioactivity attached to very minimal amounts of tracer, in the case, [18F]FTT. Because some cancers take up [18F]FTT it can be seen with PET. PARP inhibitors work as a targeted therapy by blocking an enzyme involved in repairing cell damage. It may cause tumor cells to die. ICI may help the body's immune system attack the cancer and may interfere with the ability of tumor cells to grow and spread. Combining [18F]FTT with a PET scan may help detect tumor cells better in patients with metastatic breast cancer who are receiving standard of care PARP inhibitors with our without ICI treatment.

Study Overview

• Status: Recruiting
• Conditions: Anatomic Stage IV Breast Cancer AJCC v8; Metastatic Breast Carcinoma
• Intervention / Treatment: Other: Fludeoxyglucose F-18; Procedure: Computed Tomography; Procedure: Positron Emission Tomography; Radiation: Fluorine F 18 Fluorthanatrace; Other: Electronic Health Record Review; Other: Best Practice; Procedure: Biopsy of Breast; Drug: Immune Checkpoint Inhibitor; Drug: Poly (ADP-Ribose) Polymerase Inhibitor; Procedure: Positron Emission Tomography

Detailed Description

OUTLINE: Patients are assigned to 1 of 2 arms.

Arm I: Patients receive [18F]FTT intravenously (IV) and undergo PET scan 60-75 minutes later on day 1 of initiating SOC PARP inhibitor ± ICI therapy and again at 12 weeks. At least 1-7 days later, patients undergo SOC FDG PET/computed tomography (CT) and follow up scans at 12 weeks and 6 months. Patients may also undergo tissue biopsy during screening and during follow up.

Arm II: Patients receive [18F]FTT IV and undergo PET scan 60-75 minutes later on day 1 of initiating SOC PARP inhibitor ± ICI therapy. At least 1-7 days later, patients undergo SOC FDG PET/CT and follow up scans at 12 weeks and 6 months. Patients may also undergo tissue biopsy during screening.

After initial [18F]FTT PET imaging, patients are followed-up to 6 months or until disease progression.

• Study Type: Interventional
• Enrollment (Estimated): 22
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: Jennifer Specht, MD; Phone Number: 206-606-6889; Email: jspecht@uw.edu

Study Locations

• United States
  • Washington
    • Seattle, Washington, United States, 98109
      • Recruiting
      • Fred Hutch/University of Washington Cancer Consortium
      • Principal Investigator: Jennifer Specht, MD
      • Contact: Jennifer Specht, MD; Phone Number: 206-606-6889; Email: jspecht@uw.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients must have histologically confirmed invasive breast cancer with metastatic disease
• Patients must be candidates for treatment with PARP inhibitor as a single agent or for PARP inhibitor in combination with an ICI per treating physician discretion
• Patients must have evaluable disease or at least one measurable lesion that can be assessed at baseline by CT (or magnetic resonance imaging [MRI]) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
• Age >= 18 years
• Karnofsky performance status (KPS) >= 50% or Eastern Cooperative Oncology Group (ECOG) performance status 0-2
• Archival tissue (formalin-fixed paraffin-embedded [FFPE]) from at least one metastatic site biopsy should be available prior to study enrollment; if archival tissue is not available, then a metastatic site biopsy will be required during the study screening period
• Patient must be willing to proceed with an on-treatment biopsy of metastatic site if an on-treatment [18F]FTT PET will be performed (at 12 ± 4 weeks after starting PARP inhibitor ± ICI treatment)
• For women of childbearing potential, a negative serum pregnancy test is required within 7 days prior to [18F]FTT PET imaging on day 1. For women who obtain on-treatment (12-week) [18F]FTT imaging, a negative serum pregnancy test will be required within 7 days prior to [18F]FTT PET imaging
• Men and women of reproductive potential need to agree to employ two highly effective and acceptable forms of contraception throughout their participation in the study
• Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations
• Ability to understand and the willingness to sign a written informed consent document. Informed consent must be provided prior to any study specific procedures

Exclusion Criteria:

• Patients with prior myelodysplastic syndrome or acute myeloid leukemia due to rare risk associated with PARP inhibitor therapy
• Pregnant or breastfeeding women
• Patient with a known hypersensitivity to the proposed PARP inhibitor product
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
• Patients unable to swallow orally administered medication and patients with gastrointestinal disorders likely to interfere with absorption of PARP inhibitor therapy (per investigator's discretion)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm I ([18F]FTT PET, FDG PET/CT, PARP inhibitor, ICI); Patients receive [18F]FTT IV and undergo PET scan 60-75 minutes later on day 1 of initiating SOC PARP inhibitor ± ICI therapy and again at 12 weeks. At least 1-7 days later, patients undergo SOC FDG PET/CT and follow up scans at 12 weeks and 6 months. Patients may also undergo tissue biopsy during screening and during follow up.	Other: Fludeoxyglucose F-18; Given FDG; Other Names: 18FDG; FDG; fludeoxyglucose F 18; Fludeoxyglucose (18F); Fludeoxyglucose F18; Fluorine-18 2-Fluoro-2-deoxy-D-Glucose; Fluorodeoxyglucose F18; Procedure: Computed Tomography; Undergo FDG PET/CT; Other Names: CT; CAT; CAT Scan; Computed Axial Tomography; Computerized Axial Tomography; Computerized Tomography; CT Scan; tomography; Computerized axial tomography (procedure); Computerized Tomography (CT) scan; Procedure: Positron Emission Tomography; Undergo FDG PET/CT; Other Names: Medical Imaging, Positron Emission Tomography; PET; PET Scan; Positron Emission Tomography Scan; Positron-Emission Tomography; Positron emission tomography (procedure); Radiation: Fluorine F 18 Fluorthanatrace; Given IV; Other Names: [18F]FluorThanatrace; [18F]FTT; FLUORTHANATRACE F-18; Other: Electronic Health Record Review; Ancillary studies; Other: Best Practice; Receive of standard care; Other Names: standard of care; standard therapy; Procedure: Biopsy of Breast; Undergo breast biopsy; Other Names: Breast Biopsy; Drug: Immune Checkpoint Inhibitor; Receive ICI treatment; Other Names: ICI; Drug: Poly (ADP-Ribose) Polymerase Inhibitor; Receive PARP inhibitor treatment; Other Names: PARP Inhibitor; Poly(ADP-Ribose) Polymerase Inhibitor; Procedure: Positron Emission Tomography; Undergo [18F]FTT PET; Other Names: Medical Imaging, Positron Emission Tomography; PET; PET Scan; Positron Emission Tomography Scan; Positron-Emission Tomography; Positron emission tomography (procedure)
Active Comparator: Arm II ([18F]FTT PET, FDG PET/CT, PARP inhibitor, ICI); Patients receive [18F]FTT IV and undergo PET scan 60-75 minutes later on day 1 of initiating SOC PARP inhibitor ± ICI therapy. At least 1-7 days later, patients undergo SOC FDG PET/CT and follow up scans at 12 weeks and 6 months. Patients may also undergo tissue biopsy during screening.	Other: Fludeoxyglucose F-18; Given FDG; Other Names: 18FDG; FDG; fludeoxyglucose F 18; Fludeoxyglucose (18F); Fludeoxyglucose F18; Fluorine-18 2-Fluoro-2-deoxy-D-Glucose; Fluorodeoxyglucose F18; Procedure: Computed Tomography; Undergo FDG PET/CT; Other Names: CT; CAT; CAT Scan; Computed Axial Tomography; Computerized Axial Tomography; Computerized Tomography; CT Scan; tomography; Computerized axial tomography (procedure); Computerized Tomography (CT) scan; Procedure: Positron Emission Tomography; Undergo FDG PET/CT; Other Names: Medical Imaging, Positron Emission Tomography; PET; PET Scan; Positron Emission Tomography Scan; Positron-Emission Tomography; Positron emission tomography (procedure); Radiation: Fluorine F 18 Fluorthanatrace; Given IV; Other Names: [18F]FluorThanatrace; [18F]FTT; FLUORTHANATRACE F-18; Other: Electronic Health Record Review; Ancillary studies; Other: Best Practice; Receive of standard care; Other Names: standard of care; standard therapy; Procedure: Biopsy of Breast; Undergo breast biopsy; Other Names: Breast Biopsy; Drug: Immune Checkpoint Inhibitor; Receive ICI treatment; Other Names: ICI; Drug: Poly (ADP-Ribose) Polymerase Inhibitor; Receive PARP inhibitor treatment; Other Names: PARP Inhibitor; Poly(ADP-Ribose) Polymerase Inhibitor; Procedure: Positron Emission Tomography; Undergo [18F]FTT PET; Other Names: Medical Imaging, Positron Emission Tomography; PET; PET Scan; Positron Emission Tomography Scan; Positron-Emission Tomography; Positron emission tomography (procedure)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall response rate (ORR)	Will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria on poly (ADP-ribose) polymerase (PARP) inhibitor ± immune checkpoint inhibitor (ICI) treatment. Will use a boxplot to illustrate the difference of standard uptake value (SUV)max and SUVmean between responders and non-responders.	Baseline up to 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ORR	Will be assessed using RECIST 1.1 criteria on PARP inhibitor ± ICI treatment. Will use the nonparametric method Wilcoxon Rank Sum test to evaluate the difference of the changes of SUVmax and/or SUVmean between responders and non-responders.	Baseline up to 6 months

Collaborators and Investigators

• Sponsor: University of Washington
• Collaborators: Breast Cancer Research Foundation
• Investigators: Principal Investigator: Jennifer Specht, MD, Fred Hutch/University of Washington Cancer Consortium

Study record dates

Study Major Dates

• Study Start (Actual): February 26, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2030

Study Registration Dates

• First Submitted: July 8, 2024
• First Submitted That Met QC Criteria: July 8, 2024
• First Posted (Actual): July 16, 2024

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 15, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; Antineoplastic Agents, Immunological; Antineoplastic Agents; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Health Services Administration; Health Care Quality, Access, and Evaluation; Investigative Techniques; Pharmacologic Actions; Chemical Actions and Uses; Therapeutic Uses; Quality of Health Care; Carbohydrates; Quality Indicators, Health Care; Chemistry Techniques, Analytical; Spectrum Analysis; Deoxyglucose; Deoxy Sugars; Guidelines as Topic; Quality Assurance, Health Care; Immune Checkpoint Inhibitors; Poly(ADP-ribose) Polymerase Inhibitors; Fluorodeoxyglucose F18; Standard of Care; Magnetic Resonance Spectroscopy; Practice Guidelines as Topic
• Other Study ID Numbers: RG1124440; NCI-2024-04929 (Registry Identifier: CTRP (Clinical Trial Reporting Program)); FHIRB0020495 (Other Identifier: Fred Hutch/University of Washington Cancer Consortium)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No