Study Evaluating the Safety and Tolerability of L-377202

Inclusion Criteria: * Patient is at least an 18-year-old male and has histologically documented, progressive carcinoma of the prostate which is refractory to hormonal manipulation. Progressive disease may be documented by new lesions on bone scan, increase in radiologically measurable disease, or an increase in PSA (at least 50% increase from nadir confirmed twice and measured at least 2 weeks apart.) * An appropriate interval of time has passed since alteration of any hormonal therapy (e.g., 4 weeks for steroids, LHRH agonists, flutamide or megestrol acetate and 6 weeks for nilutamide and bicalutamide). * Patient has a serum PSA of 20 ng/mL or higher. * Patient has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. * Patients has a life expectancy of \>3 months. * Patient understands and agrees to participate in the study by providing written informed consent. Exclusion Criteria: * Patient is mentally or legally incapacitated at the time of the study or has a history (less than 5 years prior to entry) of drug or alcohol abuse or is currently a user (including "recreational use") of any illicit drugs. * Patient has known HIV or a known HIV-related malignancy. * Patient has participated in another study (including FDA approved drugs for a non-FDA approved indication) of an investigational agent within the last 4 weeks. * Patient requires treatment or is anticipated to require treatment with Cyclosporine, Phenobarbital, phenytoin, or streptozocin. * Patient has received tumor directed immunologic therapy, radiation therapy, surgery, or chemotherapy within 4 weeks of the study. However, patients who are receiving thyroid replacement therapy may be included. For mitomycin or nitrosourea, there must be a 6-week treatment free interval. * Patient has received strontium treatment within 12 weeks prior to treatment. * Patient is anticipated to require immunologic therapy, radiation therapy, surgery, or chemotherapy during the study. * Patient has received high-dose chemotherapy with stem cell rescue. * Patient has a history of significant cardiac dysrhythmias (Grade 3 or higher excluding atrial fibrillation). * Patient has recently had (within 6 months) a myocardial infarction, unstable angina, or congestive heart failure. * Patient has an abnormal PT (INR) or a PTT (\>1.2 times normal). Low-dose warfarin (1 to 2 mg P.O. q.d.) or heparin (the equivalent of 5000 IU SQ b.i.d.) administered to maintain catheter patency is acceptable. Patients administered higher doses of anticoagulants may be considered on an individual basis pending discussion between the clinical monitor and investigator. Such patients will require more intensive monitoring of PT (INR) and aPTT (at least every other day). * Patient has an absolute neutrophil count \<1500/mm3 or platelet count \<100,000/mm3 or hemoglobin \<9 gm/dL, bilirubin \>1.5 times normal or ALT or AST \>2.5 times normal or creatinine \>1.5 times normal. * Patient has an active infection. * Patient has an active (edema, progressive disease, or clinical neurologic symptoms) metastatic CNS lesion. * Patient has received the equivalent of \>180 mg/m2 of doxorubicin or \>40 mg/m2 mitoxantrone. * Patient has left ventricular ejection fraction (LVEF) \<45%. * Patient has received radiation to \>25% of his total bone marrow.