[18F]FTT PET to image PARP expression in metastatic breast cancer
Official title: [18F]FTT Positron Emission Tomography (PET) in Patients With Metastatic Breast Cancer
Run by University of Washington · NCT06502691 · Data updated 2026-11-12
This test tries to see if an [18F]FTT PET scan can show PARP levels and help detect whether PARP inhibitor treatment (with or without immunotherapy) is working for people with metastatic breast cancer.
Quick facts
| Phase | Phase1; Phase2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 22 (estimated) |
| Sponsor | University of Washington Academic / other |
| Locations | 1 site (Seattle, Washington) |
| Status | Recruiting |
| Started | February 26, 2026 |
| Main results expected | December 31, 2027 |
| Study ends | December 31, 2030 |
| Registry record updated | May 19, 2026 |
| Trial ID | NCT06502691 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults (≥18) with histologically confirmed metastatic (stage IV) breast cancer who are starting PARP inhibitor therapy (alone or with an immune checkpoint inhibitor), have at least one measurable lesion, and can provide archival or new metastatic tissue are ideal candidates.
✕Probably not a fit
Patients who are not receiving PARP inhibitors, who lack measurable metastatic disease, or who cannot undergo PET imaging or required biopsies are unlikely to benefit from this protocol.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This interventional phase 1/2 protocol uses the radiotracer [18F]FTT with PET imaging to visualize PARP1 expression in patients with metastatic (stage IV) breast cancer who are starting standard-of-care PARP inhibitors with or without immune checkpoint inhibitors. Participants undergo an [18F]FTT PET on day 1 of therapy (60–75 minutes after tracer injection) and some return for repeat imaging at 12 weeks, with parallel standard-of-care FDG PET/CT performed within 1–7 days and at follow-up time points including 12 weeks and 6 months. Tissue biopsy of a metastatic site is required if archival metastatic tissue is not available and on-treatment biopsies may be obtained per protocol. Patients are followed for up to 6 months or until disease progression to compare [18F]FTT uptake with clinical response and FDG imaging.
Why it matters
Potential benefit: If successful, this imaging approach could provide a noninvasive way to visualize tumor PARP expression and detect early response to PARP inhibitor therapy, helping guide treatment decisions.
How similar studies have gone: Early-phase and preclinical studies have shown that [18F]FTT can image PARP expression, but larger clinical validation for predicting response to PARP inhibitors remains limited.
Who can join: the full rules
Show full inclusion / exclusion criteria
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)
Where it's running
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Fred Hutch/University of Washington Cancer Consortium
Seattle, Washington, United States Recruiting
Study contacts
- Principal investigator: Jennifer Specht, MD — Fred Hutch/University of Washington Cancer Consortium
- Study coordinator: Jennifer Specht, MD
- Email: jspecht@uw.edu
- Phone: 206-606-6889
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.