Inclusion Criteria:

- Histologically confirmed adenocarcinoma of the prostate

- Radiographically documented metastatic disease

- Surgical or chemical castration

- Prostate-specific antigen >=5 ng/ml

- Androgen-independent disease

- Eastern Cooperative Oncology Group performance status of 0, 1, or 2

- Protocol-defined adequate bone marrow reserve, hepatic and renal function

- Protocol-defined adequate hepatic function

- Agrees to protocol-defined use of effective contraception

Exclusion Criteria:

- Treatment with chemotherapy or radiation therapy that was terminated at least 4 weeks
before study entry

- Treatment with extensive external beam radiation therapy or radionuclide therapy
within 6 weeks of study entry (palliative radiation involving less than 20% of bone
marrow reserves must have been completed at least 4 weeks before study entry)

- Other protocol-defined serious illnesses or medical conditions