68Ga-PSMA-R2 in Patients With Biochemical Relapse (BR) and Metastatic Prostate Cancer (mPCa)

Inclusion Criteria:

1. Males 18 years or older.
2. Signed and dated written informed consent by the subject prior to any study-specific procedures.
3. Histologically confirmed adenocarcinoma of the prostate, defined as follows:

   1. Biochemical recurrence: defined as PSA is ≥0.2 ng/mL after radical prostatectomy or PSA nadir plus 2 ng/mL after radiation therapy with corresponding CT/MRI or bone scan revealing absence of local recurrence or metastatic lesions.

      OR
   2. Metastatic disease: defined as both, castration-sensitive or castration-resistant mPCa (presence of at least 1 metastatic lymph node, visceral metastasis and/or bone metastasis).
   3. At least 2 weeks must have elapsed between last anticancer treatment administration and the administration of the imaging product, 68Ga-PSMA-R2.
4. Prior major surgery must be at least 12 weeks prior to study entry.
5. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2, with a life expectancy ≥6 months.
6. Adequate bone marrow reserve and organ function as demonstrated by complete blood count, and biochemistry in blood and urine at Screening:

   1. Hemoglobin (Hb): \>8 g/dL
   2. Platelet count of \>50.000/mm3
7. Serum creatinine \<1.5\*upper limit normal (ULN) or estimated glomerular filtration rate (eGFR) \>50 mL/min based upon The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.
8. For male subjects with partners of childbearing potential, agreement to use barrier contraceptive method (condom) and to continue its use for 28 days after IP administration.

Exclusion Criteria:

1. Pathological finding consistent with small cell, neuroendocrine carcinoma of the prostate or any other histologies different than adenocarcinoma.
2. Administered a radioisotope =\<10 physical half-lives prior to the day of PET/CT.
3. Current severe urinary incontinence, hydronephrosis, severe voiding dysfunction, or need of indwelling/condom catheters.
4. Uncontrolled pain or incompatibility that results in subject's lack of compliance with imaging procedures.
5. Other known coexisting malignancies except non-melanoma skin or low grade superficial bladder cancer unless definitively treated and proven no evidence of recurrence for 5 years.
6. Subject with known incompatibility to CT scans.
7. Any evidence of severe or uncontrolled systemic or psychiatric diseases, including uncontrolled hypertension and active bleeding diatheses, which in the investigator's opinion makes it undesirable for the subject to participate in the study or which would jeopardize compliance with the protocol, or active infection including human immunodeficiency virus (HIV) and untreated hepatitis B, hepatitis C. Screening for chronic conditions was not required.
8. Subjects who have received any investigational agent within the last 28 days were excluded from participation in this study.
9. Any acute toxicity due to prior chemotherapy and/or radiotherapy that has not resolved according to the Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Studies.
10. Known allergy, hypersensitivity, or intolerance to the IP or its excipients.
11. Subject unlikely to comply with study procedures, restrictions and requirements and judged by the investigator to be unsuitable for study participation.