Inclusion Criteria:

- Patient has prostate cancer that is getting worse after treatment with
hormone-blocking therapies such as orchiectomy (removal of a testicle), prostate
cancer treatment pills (Casodex, Eulexin, Nilandrone, bicalutamide, flutamide,
nilutamide), or hormone shots (Lupron, Eligard, leuprolide, Zoladex, gosserelin)

- 18 years of age or older

- At least one dose/cycle of chemotherapy drugs (docetaxel, Taxotere, estramustine,
Emcyt, mitoxantrone, Novantrone, etc.)

- Normal kidney and liver function, and normal blood counts

- Able to swallow pills

- Use a valid form of birth control while taking the study drug and for at least 4
weeks afterwards

Exclusion Criteria:

- Chemotherapy in the last 4 weeks

- Radiation therapy in the past six weeks

- Quadramet (samarium 153) therapy (a drug used to relieve bone pain) in the past two
months, or Metastron (strontium-89), another drug used to relieve bone pain, ever

- Treatment with any tyrosine kinase inhibitor (a type of therapy that controls
cancerous cell growth). Investigational chemotherapy drugs must have been taken at
least six weeks ago, and investigational vaccines at least six months ago.

- Any other cancer, other than prostate cancer, that required chemotherapy, hormone
therapy, or radiation therapy in the past five years

- Uncontrolled heart failure, heart attack, or chest pains within the previous six
months

- History of unstable heart rhythms

- Medicines known to cause heart rhythm disturbances, including quinidine,
procainamide, disopyramide, amiodarone, sotalol, ibutilide, dofetilide, erythromycin,
clarithromycin, chlorpromazine, haloperidol, mesoridazine, thioridazine, pimozide,
cisapride, bepridil, droperidol, methadone, arsenic, chloroquine, domperidone,
halofantrine, levomethadyl, pentamidine, sparfloxacin, and lidoflazine. There are
restrictions or limitations to use of other medicines as well, such as anticoagulants
(drugs that stop blood from clotting), intravenous bisphosphonates (bone-hardening
medicines), and anti-acid agents such as omeprazole, lansoprazole, cimetidine,
ranitidine, and other H2 blockers/proton pump inhibitors. Patients may not take St.
John's Wort while on study.

- History of abnormal bleeding, such as hemophilia, von Willebrand's disease, or are
using full-dose anticoagulants (substances that stop the blood from clotting).
Patients may not have had any stomach or intestinal bleeding in the past three
months.

- Untreated brain cancer, or untreated prostate cancer causing spinal cord compression

- May not drink Grapefruit Juice during this study