Imaging Properties of PET Radiotracer [18F]3F-PHPG in Patients With Neuroendocrine Tumors

An Exploratory Study of 3-[18F]Fluoro-para-hydroxyphenethylguanidine ([18F]3F-PHPG) in Patients With Neuroendocrine Tumors

The goal of this exploratory study is to test whether [18F]3F-PHPG can be used reliably to map the locations of tumors in patients with neuroendocrine tumors. If so, the results of this study will be used to support further development of [18F]3F-PHPG as a clinical tool for neuroendocrine tumor localization and staging.

Subjects enrolled in this study will be recruited from the population of adult patients with neuroendocrine tumors, including pheochromocytoma and paraganglioma, being treated at the University of Michigan Hospital. The primary objective of the study is to obtain basic information on the biodistribution and pharmacokinetics of [18F]3F-PHPG in cancer patients with neuroendocrine tumors. The secondary objective of the study is to compare the diagnostic performance of [18F]3F-PHPG in cancer patients with neuroendocrine tumors with the FDA approved radiopharmaceuticals [123I]metaiodobenzylguanidine ([123I]MIBG) and [68Ga]DOTA-TATE in the same patients. A group of approximately 12 of the subjects scanned with [18F]3F-PHPG will be recruited to undergo a whole-body [123I]MIBG scan using planar scintigraphy with a gamma camera, following the standard clinical protocol used at the University of Michigan. In addition, a single SPECT/CT scan of the primary neuroendocrine tumor will be acquired after the whole-body scan to provide a tomographic image for comparison with the positron emission tomography (PET) image acquired using [18F]3F-PHPG. Several subjects enrolled on this study will undergo [68Ga]DOTA-TATE scans off-study, as part of routine clinical management. Existing [68Ga]DOTA-TATE scans will be obtained from consenting subjects' medical records. This is an exploratory study and thus all statistical data analyses will be exploratory in nature.

All subjects (30 anticipated) will receive a PET/CT scan using the novel radiotracer [18F]3F-PHPG as an imaging agent. Within 60 days after the [18F]3F-PHPG PET/CT scan, approximately 12 of the subjects will also receive an FDA approved radiotracer [123I]MIBG one day prior to whole-body planar scintigraphy and SPECT/CT scans. The [123I]MIBG scans are standard clinical imaging procedures.

FDA approved radiotracer [123I]MIBG prior to whole-body planar scintigraphy and SPECT/CT scan (standard clinical imaging procedures).

Whole-body PET/CT scan performed at two time-points: 1.5 hours and 3 hours after IV injection of [18F]3F-PHPG

Whole-body scan using planar scintigraphy with a gamma camera performed the day after IV injection of [123I]MIBG

The maximum standardized uptake value (SUVmax) of [18F]3F-PHPG in neoplastic lesions will be quantified from the PET images using region-of-interest (ROI) analysis.

Changes in the measured tissue concentrations (kBq/cc) of [18F]3F-PHPG in neoplastic lesions and abdominal organs from the two acquired PET images (acquired at 90 min and 180 min after tracer injection).

Inclusion Criteria: Current neuroendocrine tumor diagnosis Able to lie flat for 60 minutes Provision of informed consent Exclusion Criteria: Pregnancy or lactation Claustrophobia Inability to lie flat for 60 minutes Currently taking medications that may alter PET scans of neuroendocrine tumors with these tracers, including any of the following: Tricyclic antidepressants, which inhibit the norepinephrine transporter: desipramine, amitriptyline, imipramine Cold medications containing the sympathomimetic amines: phenylephrine, phenylpropanolamine, pseudoephedrine Nasal decongestants (some use phenylephrine as the active agent) Cocaine (which inhibits the norepinephrine transporter) Tetrabenazine (Xenazine), which inhibits the VMAT2 transporter Monoamine oxidase inhibitors (MAOI) Some antihypertensive drugs: reserpine, labetalol, α-methyldopa, clonidine