Treatment With Radiolabeled Monoclonal Antibody HuJ591-GS (177Lu-J591) in Patients With Metastatic Prostate Cancer

To determine the clinical activity of 177Lu -J591 for the treatment of patients with
metastatic, androgen-independent prostate cancer.

Patients will receive a single dose of J591 (total antibody of 20 mg) consisting of antibody
chelated with 177Lu at a dose of 65 or 70 mCi/m2 with a specific activity of 12-15 mCi/mg
plus non-radiolabeled antibody.

Inclusion Criteria:

- Histologic diagnosis of prostate adenocarcinoma.

- Metastatic prostate cancer progressive on imaging studies and/or rising PSA despite
adequate medical or surgical castration therapy.

- Progressed following discontinuation of anti-androgen therapy, if received.

- Serum testosterone < 50 ng/ml

Exclusion Criteria:

- Use of corticosteroids and/or adrenal hormone inhibitors within 4 weeks of treatment.

- Use of PC-SPES within 4 weeks of treatment.

- Use of red blood cell or platelet transfusions within 4 weeks of treatment.

- Use of hematopoietic growth factors within 4 weeks of treatment.

- Prior cytotoxic chemotherapy and/or radiation therapy within 4 weeks of treatment.

- Bone scan demonstrating confluent lesions involving both axial and appendicular
skeleton.

- Prior radiation therapy encompassing >25% of skeleton.

- Prior treatment with 89Strontium or 153Samarium containing compounds (e.g. Metastron®,
Quadramet®).

- Active angina pectoris or NY Heart Association Class III-IV.

- History of deep vein thrombophlebitis and/or pulmonary embolus within 3 months of
study entry.

- Other serious illness(es) involving the cardiac, respiratory, CNS, renal, hepatic or
hematological organ systems which might preclude completion of this study or interfere
with determination of causality of any adverse effects experienced in this study.

- Prior monoclonal antibody therapy with the exception of ProstaScint®

- Prior investigational therapy (medications or devices) within 6 weeks of treatment.

- Known history of HIV