Four-Timepoint Multi-tracer PET Imaging to Characterize Metastatic prOstate Cancer Heterogeneity

NCT07302763 | Recruiting DMC

• 1 other identifier: 2025-7376
• Study Type: interventional
• Target: 45
• Locations: 1 country
• Sites: 1

Brief Summary

Imaging modalities currently used in the clinics do not image cancer, but the effect ofncancer on bone (bone scan) or on the anatomy (CT-scan). Bone scan and CT-scan are therefore named conventional imaging (CI) modalities. Positron Emission Tomography (PET) is an imaging technique that uses tracers to measure cancer activity in each lesion and is therefore quantitative. Usually, treatment changes in metastatic prostate cancers are based on the appearance of new lesions on CI, named metastases. Prostate cancer metastases have been shown to be clonal, which means that there are several cancers within each patient, potentially with divergent behaviors under therapy. In other words, some metastases might be resistant to a systemic therapy like chemotherapy, while others might be sensitive. The study proposes here to use molecular imaging by positron emission tomography to image and quantify the activity of prostate cancer cells in each metastasis before start, after 3 months and after progression during systemic therapy. Each metastasis will then be measured to assess whether there is an increase (resistance) or a decrease (response) in prostate cancer cell activity. The analysis will determine how many metastases progress or remain stable when new metastases appear on conventional imaging (polyclonal resistance), as well as the impact of a change in therapy on metastases that were previously stable when cancer progressed elsewhere. In addition, the genes expressed in responding and non-responding metastases will be analyzed to identify gene expression patterns associated with resistance and/or response. Overall, this study aims to characterize metastatic prostate cancer clonal resistance mechanisms using serial PET molecular imaging and imaging-guided genomics.

Conditions

mCRPC (Metastatic Castration-resistant Prostate Cancer)

Keywords

oncology; molecular imaging tracers

Outcome Measures

Primary Outcomes (2)

• Determine the change in prevalence of IIH of mCRPC undergoing consecutive lines of systemic therapy.

  Percentage of patients that show heterogeneous FDG and PSMA tracer uptakes between at least two metastases at baseline and at each progression following consecutive lines1 of study systemic therapies.

  At Baseline and at the date of first and second documented progression, assessed up to 60 months

• Determine intrapatient intermetastasis therapeutic heterogeneous response (IIHR) in mCRPC patients.

  Percentage of patients that show opposite FDG and/or PSMA tracer uptake and/or ratio responses between two metastases after first and second study systemic therapy.

  At the date of first and second documented progression, assessed up to 60 months

Secondary Outcomes (2)

• Evaluate the impact of systemic treatment change on progressing and non-progressing FDG or PSMA PET lesions under last treatment.

  At the date of first and second documented progression, assessed up to 60 months

• Correlate histopathology of biopsies to imaging phenotypes.

  At the date of first and second documented progression, assessed up to 60 months

Other Outcomes (1)

• Link radiomic, and genomic features of single-timepoint and sequential multitracer PET imaging with clinical outcomes. Characterize the biological features of FDG positive/DOTATATE any/PSMA negative lesions (poor prognosis) vs PSMA positive/FDG any/DO

  At the date of randomization, then 3 months after randomizaton and at the date of first and second documented progression, assessed up to 60 months

Study Arms (1)

PET with FDG, PSMA and DOTATATE

EXPERIMENTAL

Diagnostic Test: PET Tracer

Interventions

PET Tracer DIAGNOSTIC_TEST

Multi-tracer PET imaging to characterize metastatic prOstate Cancer heterogeneity

PET with FDG, PSMA and DOTATATE

Eligibility Criteria

• Age: 18 Years+
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Assign male at birth, any gender ≥ 18 years old;
• Histologically or cytologically proven adenocarcinoma of the prostate;
• Metastatic disease documented by at least 3 metastatic active lesions\*, \*\* on whole body bone scan and/or measurable soft tissue on CT-scan (lymph nodes and visceral lesions);
• CRPC \& post-androgen receptor pathway inhibitor (ARPI) defined by progression under continuous castration (measured serum testosterone ≤50 ng/dL \[1.73 nM\]) AND an ARPI (darolutamide, apalutamide, enzalutamide or abiraterone acetate);
• Eligible for taxane chemotherapy or PSMA-radioligand therapy (before imaging); 6-Able and willing to provide signed informed consent and to comply with protocol requirements.
• Metastatic lesions on imaging are defined either: ≥ 10 mm on CT scan or caliper (for lymph nodes, see below), ≥ 20 mm on chest X-ray, lymph node ≥ 10 mm or having grown by ≥ 5 mm from baseline CT, any metastasis described on bone scan counts as a lesion. Of note: A bone lesion that has been treated by radiation is excluded from the lesions counted in the criterion of ≥ 3 lesions.
• The reference imaging (scan with 3 metastases) confirming eligibility must be done either: 1) after biochemical progression on treatment OR 2) ≥ 90 days after last treatment has begun if imaging was performed while patient was still responding (to avoid disappearance of metastasis due to response).

You may not qualify if:

• \. Another non-cutaneous malignancy or melanoma diagnosed in the past 5 years; 2. Currently under a randomized controlled trial with unknown allocation; 3-Any disease or condition limiting the patient's capacity to execute the study procedures, based on the investigators' opinion;

Sponsors & Collaborators

• Frederic Pouliot: lead

Study Sites (1)

CHU de Québec-Université Laval

Québec, Quebec, G1J1Z4, Canada

RECRUITING

MeSH Terms

Conditions

Neoplasms

Study Officials

• Frédéric Pouliot, MD, PhD

  CHU de Québec-Université Laval

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Marie-Christine Dubé, PhD

CONTACT

418-525-4444; marie-christine.dube@crchudequebec.ulaval.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: November 17, 2025
• First Posted: December 24, 2025
• Study Start: November 4, 2025
• Primary Completion (Estimated): December 31, 2029
• Study Completion (Estimated): December 31, 2030
• Last Updated: December 24, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)