This is a Phase II study to test the efficacy of exogenously administered GM-CSF in prostate cancer patients who have failed definitive local therapy, and have only serologic (PSA) evidence of progression.

Inclusion Criteria:

• Histologic diagnosis of adenocarcinoma of the prostate; stage T1-T3, N0-N1, M0
• Prior definitive therapy for primary prostate cancer consisting of:external beam radiotherapy;brachytherapy with or without pelvic external beam radiation; or radical prostatectomy with or without adjuvant or salvage radiation therapy
• Therapeutic PSA response to primary therapy below 1.0 ng/ml post radiation therapy or below 0.4 ng/ml for radical prostatectomy
• Patients treated with adjuvant or salvage radiation therapy following radical prostatectomy are eligible provided:Post prostatectomy PSA was never > 6.0 ng/ml, last effective day of androgen deprivation is at least 3 months prior to study entry
• Recurrent PSA level elevation (between 0.4 ng/ml and 6.0 ng/ml) on two determinations at least one week apart.
• No clinical evidence of gross local recurrence or known metastatic disease other than PSA elevation. Transrectal ultrasound and/or biopsy to evaluate local recurrence is not required. All patients will receive a bone scan and CT scan of the abdomen to exclude metastases.
• Estimated life expectancy of at least 6 months.
• ECOG Performance status of 0 or 1.
• Willing and able to give informed consent.

Exclusion Criteria:

• Cryosurgery as definitive therapy of primary tumor.
• Any metastasis.
• No concurrent or prior malignancy is allowed except for the following: adequately treated basal or squamous cell skin cancer, adequately treated Stage I or II cancer from which the patient is currently in complete remission, or any other cancer from which the patient has been disease-free for 5 years.
• Current systemic steroid therapy (inhaled or topical steroids acceptable).
• Prior hormonal therapy for treatment of progressive disease.
• Prior chemotherapy, immunotherapy, or therapy with other experimental agents for prostate cancer.
• Any surgery within the prior 4 weeks.
• Bilirubin and SGOT > 2 x upper limit of normal.
• BUN and serum creatinine > 2.0 times normal.
• No active congestive heart failure.
• If there is a history of clinically significant obstructive airway disease, a DLCO must exceed 50%.
• Active uncontrolled bacterial, viral or fungal infection until these conditions are corrected or controlled.
• Any underlying medical condition which in the principal investigator's opinion will make the administration of GM-CSF hazardous or obscure the interpretation of adverse events.
• PSA > 6.0 ng/ml