Gallium-68 Citrate PET Used in Prostate Cancer

This is a single center, pilot, cross-sectional imaging study investigating the use of gallium-68 citrate PET in participants with metastatic castration-resistant prostate cancer who are planning to undergo a metastatic tumor biopsy on protocol NCT02432001 (CC#125519).

The study population will consist of participants with metastatic castration-resistant prostate cancer who are undergoing a metastatic tumor biopsy as part of clinical protocol NCT02432001 (CC#125519), with evidence of resistance to androgen signaling inhibition.

Primary Objective:

I. To determine the association between maximum average of standard uptake value (SUVmax-ave) of target metastatic lesions on gallium-68 citrate PET with MYC amplification determined from analysis of circulating tumor DNA.

Secondary Objectives:

I. To determine the accuracy rate, sensitivity, specificity of gallium citrate PET in the detection of metastatic lesions as compared to standard staging scans including cross-sectional imaging of the abdomen/pelvis and whole body bone scan.

II. To determine the optimal dose of gallium-68 citrate and timing of scan post-injection to maximize tumor-to-background signal.

III. To characterize the safety profile of gallium-68 citrate.

Outline:

The study will involve gallium-68 PET scan obtained on a single day, followed by optional tumor biopsy within 6 weeks of gallium scan. There will be optional follow up gallium-68 citrate PET scan to assess response to treatment that will be completed within 12 weeks of baseline gallium citrate PET.

Eligibility Criteria:
Inclusion Criteria:

* Male participants with histologically confirmed prostate cancer
* Participants must have castrate levels of testosterone (\< 50 ng/dL) on Luteinizing hormone-releasing hormone (LHRH) analogue or have had prior bilateral orchiectomy, with evidence of castration-resistant disease by Prostate Cancer Clinical Trials Working Group 2 (PCWG2) criteria
* Age 18 years or older at the time of study entry
* Minimum of at least three discrete metastatic lesions in the bone and/or soft tissue amenable to whole body Positron Emission Tomography (PET) imaging per the judgment of study radiologist

For participants who undergo optional metastatic tumor biopsy following completion of gallium citrate PET:

* Presence of one or more metastases by standard radiographic scans that is safely accessible to tumor biopsy in the judgment of treating clinician and/or Interventional Radiology

Exclusion Criteria:

* Contra-indications to MRI, including permanent pacemaker, implantable device, aneurysm clip, or severe claustrophobia (for participants planning to be imaged on PET/ Magnetic resonance imaging(MRI) scanner)
* Active infection within 14 days of study enrollment

For participants who undergo optional metastatic tumor biopsy following completion of gallium citrate PET:

* History of radiation therapy to the target metastatic lesion selected for tumor biopsy
* Contra-indication to biopsy including uncontrolled bleeding diathesis.
* Platelets \>75,000/μl and prothrombin time (PT) or international normalized ratio (INR) and a partial prothrombin time (PTT) \< 1.5 times the institutional upper limit of normal (ULN) within 14 days prior to biopsy.