Inclusion Criteria:

- All patients must have a histologic diagnosis of adenocarcinoma of the prostate stage
D2 that is unresponsive or refractory to hormone therapy; patients must have
metastatic prostate cancer deemed to be hormone refractory by one or more of the
following (despite androgen deprivation and anti-androgen withdrawal when
applicable):

- Progression or unidimensionally measurable disease assessed within 28 days prior
to initial administration of drug

- Progression of evaluable but not measurable disease assessed within 28 days
prior to initial administration of drug for PSA evaluation and within 42 days
for imaging studies (e.g. bone scans)

- Rising PSA, defined as at least two consecutive rises in PSA to be documented
over a reference value; the first rising PSA should be taken at least 7 days
after the reference value; a third confirmatory PSA measure should be greater
than the second measure, and it must be obtained at least 7 days after the 2nd
measure; if this is not the case, a fourth PSA is required to be taken and be
greater than the second measure

- All patients must have pre-study PSA within 28 days prior to initial administration
of drug

- Patients who have measurable disease must have mad x-rays, scans or physical
examinations used for tumor measurement completed within 28 days prior to initial
administration of drug; patients must have non-measurable disease within 28 days (for
PSA level) or 42 days (for imaging studies) prior to initial administration of drug;
soft tissue disease that has been radiated within the two months prior to
registration is not assessable as measurable disease; soft tissue disease that has
been radiated two or more months prior to registration is assessable as measurable
disease provided that the lesion has progressed following radiation; as the biology
of previously irradiated tumor may be different from non-irradiated tumors, patients
must have at least one measurable lesion outside the previously irradiated region in
order to be considered to have measurable disease

- Patients must have bone metastases as documented by x-ray, bone scan, MRI, or biopsy

- Patients must agree to have serum and urine samples taken approximately every eight
weeks and submitted for correlative studies

- All patients must have had a CT scan of the abdomen and pelvis within 28 days prior
to initial administration of drug; bone scans must be performed within 42 days of
initial drug administration

- Patients must have been surgically or medically castrated; if the method of
castration was LHRH agonists (leuprolide or goserelin), then the patient must be
willing to continue the use of LHRH agonists

- If the patient has been treated with non-steroidal anti-androgens (flutamide,
bicalutamide or nilutamide) or other hormonal treatment (such as ketoconazole), these
agents must have been stopped at least 28 days prior to enrollment for flutamide or
ketoconazole, and at least 42 days prior to enrollment for bicalutamide or
nilutamide; and the patients must have demonstrated progression of disease since the
agents were suspended

- Prior radiation therapy is allowed; at least 21 days must have elapsed since the
completion of radiation therapy, and the patient must have recovered from the side
effects of the radiation; if the patient has received strontium 89 or samarium 153,
at least three months must have elapsed since completion of therapy, and the patient
must have recovered from side effects of therapy, and the AGC and platelets must meet
the parameters specified

- No more than one prior chemotherapy regimen is allowed; at least 3 weeks must have
elapsed since the completion of the chemotherapy, and the patient must have recovered
from the side effects of the therapy

- Patients must have a Karnofsky performance status of 60-100%

- Platelet count of >= 100,000/uL

- Serum bilirubin =< the institutional upper limit of normal

- SGOT and SGPT =< 2 x institutional upper limit of normal

- Serum creatinine =< 1.5 mg/dl or a calculated creatinine clearance of >= 60mL/min

- No other chemotherapeutic agents, biological response modifiers, radiation therapy,
corticosteroid or hormonal concomitant therapy (other than continuing LHRH treatment)
may be given during protocol treatment; bisphosphonates may not be given during
protocol treatment except under the circumstances outlined; no unconventional therapy
(e.g. St. John's Wort, PC-SPES, or any other herbal remedies taken for the purpose of
treating prostate cancer) may be given during protocol treatment

- Patients must not be planning to begin bisphosphonates; patients already receiving
bisphosphonates may continue and are eligible provided that they have progressive
disease documented while on bisphosphonate therapy

- Patients with a history of brain metastases, or who currently have treated or
untreated brain metastases, are not eligible

- Patients must have recovered from major infections and/or surgical procedures and, in
the opinion of the investigator, not have significant active concurrent other medical
illness precluding protocol treatment

- Men of reproductive potential must agree to use an effective contraceptive method

- No prior malignancy is allowed except for the following: adequately treated basal
cell or squamous cell skin cancer, in situ carcinoma of any site, 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

- All patients must be informed of the investigational nature of this study and must
sign and give written informed consent in accordance with institutional and federal
guidelines

Exclusion Criteria:

- AGC >= 1,500/uL