Vaccine Therapy with or without Sargramostim in Treating Patients with Metastatic Prostate Cancer

Inclusion Criteria

• Patients with a histologic diagnosis of adenocarcinoma of the prostate
• Patients must have metastatic prostate cancer (clinical stage D1 or D2 disease), with previously documented lymph node, soft tissue and/or bone metastases by radiographic imaging (including computed tomography [CT] [or magnetic resonance imaging (MRI)] of abdomen and pelvis and bone scintigraphy); patients in situations in which there is a reasonable clinical suspicion of a second primary tumor (or other non-prostate cancer reason for radiographic abnormalities) are not eligible unless metastatic disease is histologically confirmed to be prostate cancer
• Patients must have started androgen deprivation therapy (bilateral orchiectomy versus luteinizing hormone-releasing hormone [LHRH] agonist, and with or without androgen antagonist) at least one month (4 weeks) prior to enrollment and no more than six months (24 weeks) prior to enrollment; patients must continue the androgen deprivation therapy throughout the study period, and patients are not permitted to change the type of androgen deprivation therapy (e.g. by adding an androgen antagonist) during the course of investigational therapy
• Patients must have a serum testosterone < 50 ng/dL demonstrated within 1 month of study entry
• Patients must either not be a candidate for docetaxel chemotherapy for newly diagnosed metastatic prostate cancer, as determined by their treating oncologist, or have declined this therapy
• Patients must have evidence of response to androgen deprivation as defined by a documented decline in serum PSA values from pre-androgen deprivation treatment baseline and without evidence of PSA progression while on androgen deprivation (defined by Prostate Cancer Working Group 2 [PCWG2] criteria as a 25% increase in serum PSA and an absolute increase of 2 ng/mL over nadir)
• Patients with a prior history of a second malignancy are eligible provided they have been treated with curative intent and have been free of disease greater than three years; there will be no exclusion for patients with a history of basal cell carcinoma, squamous cell skin cancer, or other in situ carcinoma that has been adequately treated
• Patients who are sexually active must use a reliable form of contraception while on study and for 4 weeks after the last immunization
• Eastern Cooperative Oncology Group (ECOG) performance score < 2
• White blood count (WBC) >= 3000/mm^3
• Hematocrit >= 30%
• Platelet count >= 100,000/mm^3
• Serum creatinine =< 1.6 mg/dl or a calculated creatinine clearance >= 60 cc/min
• Serum bilirubin =< 2.0 mg/dl
• Patients must be informed of the experimental nature of the study and its potential risks and must sign an Institutional Review Board (IRB)-approved written informed consent form indicating such an understanding

Exclusion Criteria

• Small cell or other (non-adenocarcinoma) variant prostate cancer histology
• Patients cannot have evidence of immunosuppression or have been treated with immunosuppressive therapy, such as chemotherapy, chronic treatment dose corticosteroids (greater than the equivalent of 10 mg prednisone per day), or radiation therapy to > 30% of the bone marrow, within 6 months of the first vaccination; treatment or salvage radiation therapy encompassing =< 30% of bone marrow must have been completed 4 weeks prior to the first vaccination
• Seropositive for human immunodeficiency virus (HIV), hepatitis B (HBV) or hepatitis C (HCV) per patient history
• Patients previously treated with neoadjuvant and/or adjuvant androgen deprivation (e.g. with radiation therapy) prior to the 6-month eligibility period are allowed, assuming they did not meet criteria for progression (defined by PCWG2 criteria as a 25% increase in serum PSA and an absolute increase of 2 ng/mL over nadir) while on treatment
• Patients must not be concurrently taking other medications or supplements with known hormonal effects (other than LHRH agonists or non-steroidal antiandrogen), including prostate cancer (PC)-SPES, megestrol acetate, finasteride, ketoconazole, estradiol, or saw palmetto; all other medications with possible anti-cancer effects must be discussed with the protocol principal investigator prior to study entry
• Patients previously treated with herbal supplements, or other potential or experimental therapies for prostate cancer (apart from LHRH agonists and antiandrogens), must have been discontinued these treatments and completed at least a one-month washout prior to first vaccination
• Patients must not have plans to receive concomitant chemotherapy, other biological or immune therapies, or radiation therapy for the treatment of prostate cancer during the period of study treatment
• Patients must not have known psychological or sociological conditions, addictive disorders or family problems, which would preclude compliance with the protocol
• Patients must not have known allergic reactions to GM-CSF or the tetanus vaccine
• Prior treatment with another experimental anti-tumor vaccine is permissible
• Patients with unstable or severe intercurrent medical conditions or laboratory abnormalities that would impart, in the judgment of the protocol principal investigator, excess risk associated with study participation or study agent administration
• Unwilling to undergo two leukapheresis procedures; if patients are unable to undergo the leukapheresis procedures, then a 200-cc blood draw (green heparinized tubes) is permitted in place of the leukapheresis
• Patients with medical conditions precluding leukapheresis
• Patients cannot have concurrent enrollment on other phase I, II, or III investigational treatment studies for the treatment of prostate cancer