99mTc-PSMA-I&S Biodistribution in Patients With Prostate Cancer

99mTc-PSMA-I&Amp;S in Patients With Prostate Cancer: An Exploratory Biodistribution Study With Histopathology Validation

This exploratory study conducted under the RDRC program studies the biodistribution of 99mTc-PSMA-I&S in patients with prostate cancer who undergo pelvic lymph node dissection. Prostate specific membrane antigen (PSMA)-targeted radio-guided surgery uses the preoperative intravenous administration of a PSMA-ligand called PSMA-imaging and surgery (I&S) labeled with the gamma-emitter radioisotope Technetium-99m (99mTc). Giving 99mTc-PSMA-I&S may detect PSMA-expressing lymph nodes during surgery using a gamma probe and may help guide doctors to detect prostate cancer that has spread to the lymph nodes.

PRIMARY OBJECTIVE:

I. To define the biodistribution of 99mTc-based PSMA imaging and surgery agent (99mTc-PSMA-I&S) in normal and malignant tissues of patients with prostate cancer (PCa) with histopathology validation, when available.

SECONDARY OBJECTIVES:

I. To correlate the 99mTc-PSMA-I&S accumulation within tumor lesions observed by in-vivo single-photon emission computed tomography (SPECT), ex-vivo gamma measurements and level of prostate-specific membrane antigen (PSMA) expression quantified by histopathology, when available.

II. To define the best time-point for radio-guided surgery (RGS) with the highest tumor-to-background ratio following 99mTc-PSMA-I&S administration.

OUTLINE:

The first 5 patients receive an initial dose of 99mTc-PSMA-I&S intravenously (IV) followed by 5 SPECT/CT scans at 3-5, 5-20, 17-21, 25-29, and 40-46 hours later. These 5 patients then receive a second dose of 99mTc-PSMA-I&S IV and then undergo standard of care surgery. All subsequent patients receive one dose of 99mTc-PSMA-I&S IV before surgery.

Inclusion Criteria:

• Men with PCa (primary or recurrent disease)
• Men who received a 68Ga-PSMA-11 positron emission tomography (PET)/computed tomography (CT) for staging or restaging
• Men with evidence of lymph nodes (LNs)-positive disease on 68Ga-PSMA-11 PET/CT
• Men who are scheduled for pelvic LN dissection (PLND)
• Men who can provide oral and written informed consent
• Men who can comply with study procedures

Exclusion Criteria:

• Patients who started any PCa treatment between study enrollment and surgery
• Technically inaccessible nodal location