Gallium 68 Pentixafor in Patients With Neuroendocrine Tumors

Study Overview
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Brief Summary
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This study will evaluate how Gallium-68 Pentixafor is distributed in neuroendocrine tumor patients and if that distribution is consistent through repeated scans. This is an RDRC study - as such, the images obtained for this study cannot be used clinically or shared with treating oncologists.

Detailed Description
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High grade neuroendocrine tumors often do not express somatostatin (sstr) receptors but often express the CXCR4 receptor. The CXCR4 receptor is a marker of poorly differentiated cells. Pentixafor is a peptide that targets these CXCR4 receptors. By combining it with gallium-68, a radionuclide, pentixafor can then be evaluated as an imaging agent to detect high-grade neuroendocrine tumors. [68Ga]Pentixafor is a radio-labelled imaging agent used for positron emission tomography (PET). The dose is small, known as a tracer dose. It is designed to capture information about the body and how the body is working without interfering or causing an effect. The goal of this study is to evaluate how the [68Ga]Pentixafor is distributed through the body after injection and how it is taken up by the organs of the body. The study will also examine if the imaging is reproducible to determine if the PET images show the same uptake of the study drug across different scans. This study is an RDRC study - the equivalent to a phase 0 study. The [68Ga]Pentixafor has not been shown to target tumors; specificity and sensitivity have not been established. For this reason, images obtained for this study cannot be used clinically or shared with treating oncologists.

Official Title
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Biodistribution of Ga-68 Pentixafor in Patients With Neuroendocrine Tumors

Conditions
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Neuroendocrine Tumors

Intervention / Treatment
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* Drug: [68Ga]Pentixafor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Histological diagnosis of neuroendocrine tumor (NET). Had a prior 68Ga DOTATATE PET/CT scan (NetSpot) and a CT or MRI with or without contrast performed within 3 months before signing the consent, without interval treatment other than a somatostatin analog. CT or MRI must demonstrate at least one lesion (primary or metastatic) present 1.5 cm or larger in any dimension on cross-sectional imaging (CT or MRI) obtained within 3 months of study enrollment. Results of CXCR4 immunohistochemistry or slides from biopsy of primary tumor or metastatic lesions available for study analysis. Participation in the Iowa Neuroendocrine Tumor Registry. Exclusion Criteria: Uncontrolled intercurrent illness including, but not limited to ongoing or active infection requiring hospitalization, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. Physical limitation that would limit compliance with the study requirements Pregnant or lactating women. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. A negative pregnancy test will be required for all female subjects with child bearing potential. Planned administration of any NET therapy between scan 1 and 2, except for Somatostatin analog.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: [68Ga]Pentixafor PET scan<br>4 mCi (range 3-5 mCi) of [68Ga]Pentixafor is administered intravenously over 1 minute using an infusion pump. PET imaging is performed from time of infusion for about 90 minutes. Approximately 12 blood samples (  1 tsp) will be taken for pharmacokinetic analysis. | Drug: [68Ga]Pentixafor<br>* 68Ga Pentixafor is a radiolabeled cyclic pentapeptide with high affinity for CXCR4 receptor<br>* Other names: (68Ga)pentixafor;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determine biodistribution (pharmacokinetic parameters) of [68Ga]Pentixafor in patients with neuroendocrine tumors (NETs) | Biodistribution will be assessed through the radiotracer parameters standardized uptake value (SUV) and K-influx obtained from PET scan and blood samples.These values provide a pharmacokinetic profile of the investigational drug's biodistribution in the body. | Within 1 month of [68Ga]Pentixafor scan | 
| Determine the repeatability of [68Ga]Pentixafor uptake in known neuroendocrine tumor lesions | Determine the difference, in any, of the biodistribution values between scans 1 and 2, for subjects who undergo 2 [68Ga]Pentixafor scans. | Within 1 month of the second [68Ga]Pentixafor scan | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compare standardized uptake values of [68Ga]Pentixafor and [68Ga]DOTATATE in known neuroendocrine tumor lesions | The standardized uptake value (SUV) of known neuroendocrine tumors for the investigational agent [68Ga]Pentixafor will be compared to the SUV for [68Ga]DOTATATE (NetSpot). | Within 6 months of [68Ga]Pentixafor scan | 
| Correlate the uptake of [68Ga]Pentixafor and [68Ga]DOTATATE (NetSpot) in known neuroendocrine tumor lesions with expression of receptors (CXCR4 and SSTR2) in biopsy tissue samples. | The standardized uptake value (SUV) of the gallium PET tracers ( [68Ga]Pentixafor and/or [68Ga]DOTATATE) will be compared to the receptor expression score (H-score) | Within 6 months of [68Ga]Pentixafor scan | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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68Ga-pentixafor, (68Ga)pentixafor, Gallium Radioisotopes, CXCR4