Gallium 68 Pentixafor in Patients With Neuroendocrine Tumors

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.

Inclusion Criteria:

1. Age ≥ 18 years

2. Histological diagnosis of neuroendocrine tumor (NET).

3. 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.

4. 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.

5. Results of CXCR4 immunohistochemistry or slides from biopsy of primary tumor or
metastatic lesions available for study analysis.

6. Participation in the Iowa Neuroendocrine Tumor Registry.

Exclusion Criteria:

1. 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.

2. Physical limitation that would limit compliance with the study requirements

3. 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.

4. Planned administration of any NET therapy between scan 1 and 2, except for
Somatostatin analog.