Inclusion Criteria

Subjects must meet all of the following criteria to be enrolled in this study.

1. Male aged 18 years or older

2. Signed written informed consent and willingness to comply with protocol requirements

3. Histologic diagnosis of prostate cancer by validated history and/or biopsy of the
prostate or of a metastatic lesion.

4. Evidence of metastatic disease as documented by an abnormal bone scan and CT scan or
MRI plus:

- Castration/anti androgen therapy naïve/sensitive:

1. Gleason Score ≥ 7 and PSA ≥ 2.0 ng/mL with history of prostatectomy or
primary radiation therapy of the prostate gland and prior undetectable PSA
or; PSA > 10.0 ng/mL if intact prostate, or

2. Gleason score ≤ 6 and PSA is ≥ 20 ng/mL, or

3. Gleason Score ≥ 8 and any doubling of PSA, or PSA > 0.5 ng/mL, or

4. Clinical Stage 3 and Gleason Score ≥ 8

If on anti androgen therapy, must have initiated therapy at least 4 weeks prior to
treatment.

- Castration/anti androgen therapy resistant:

1. Patients must have current or historical evidence of disease progression
concomitant with surgical (orchiectomy) or medical castration (LHRH
analogue); anti androgen withdrawal (4 weeks for flutamide and 6 weeks for
nilutamide or bicalutamide) is necessary only for patients on anti
androgens who have demonstrated a > 3 month duration of beneficial response
to anti androgens; progression is demonstrated by any of the following:

I. PSA progression: 2 serial rising PSA determinations at least 14 days apart over
the PSA nadir, with the last measurement ≥ 2 ng/mL

II. Progression of measurable disease, or progression of non measurable disease as
defined by:

i. Soft tissue disease: The appearance of one or more new lesions, and/or unequivocal
worsening of non measurable disease when compared to imaging studies acquired during
castration therapy or against the precastration studies if there was no response, or
ii. Bone disease: Appearance of two or more new areas of abnormal uptake on bone scan
when compared to imaging studies acquired during castration therapy or against the
pre castration studies if there was no response.

III. Increased uptake of pre existing lesions on bone scan does not constitute
progression.

IV. Testosterone ≤ 50 ng/dL achieved via medical or surgical castration.

5. Male subjects who are fertile agree to use an acceptable form of birth control,
defined as abstinence, barrier or other acceptable, effective contraceptive method
throughout the study period. A second form of barrier birth control must be utilized
if a subject's partner is using oral contraception until at least seven days after
the last injection.

6. Karnofsky performance is ≥ 50

7. Adequate hematologic, renal and liver function:

- WBC ≥ 2.0×103/mm3 (ANC > 1.0 x 103 mm3)

- Platelet count ≥ 75×103/mm3

- Hemoglobin ≥ 9.0 g/dL

- Creatinine ≤ 2.5 mg/dL

- Total bilirubin ≤ 2x ULN

- AST, ALT ≤ 5x ULN

Exclusion Criteria:

1. Karnofsky performance status of < 50

2. Subject has received a permanent prostate brachytherapy implant within the last 3
months for 103Pd implants or 12 months for 125I implants

3. Subject was administered a diagnostic radioisotope within 5 physical half lives of
that radioisotope prior to study enrollment

4. Subject has received an investigational compound and/or medical device or has been
part of an investigational study within the past 30 days before enrollment into this
study

5. Any treatment with radiopharmaceuticals, e.g. Strontium 89 and Samarium 153 within 6
months prior to enrollment

6. Ketoconazole or anti androgens (flutamide, nilutamide, bicalutamide) within 4 weeks
prior to enrollment. Patients who demonstrate an antiandrogen withdrawal response,
defined as a > 25% drop in PSA within 4 weeks (flutamide) or 6 weeks (nilutamide,
bicalutamide) of stopping a non steroidal anti androgen, are not eligible until the
PSA rises above the nadir observed after anti androgen withdrawal

7. Initiation of bisphosphonate therapy within 28 days prior to enrollment. Patients
taking bisphosphonates should not have their dosing regimen altered unless medically
warranted in the interval between baseline scans and end of study

8. Subject has any medical condition or other circumstances which, in the opinion of the
Investigator, would significantly decrease the chances of obtaining reliable data,
achieving study objectives, or completing the study and/or post dose follow up
examinations

9. Subject is determined by the Investigator to be clinically unsuitable for the study

10. If the subject has had any other malignancies within the past year, other than basal
or squamous cell carcinoma of the skin, diagnosis and location must be defined or be
defined as clinically controlled or treated to complete response