Eribulin Mesylate in Treating Patients With Metastatic Prostate Cancer That Did Not Respond to Hormone Therapy

PRIMARY OBJECTIVES: I. Determine the number of patients with a \> 50% decrease in prostate-specific antigen (PSA) of at least 4 weeks duration in patients with hormone-refractory metastatic prostate cancer treated with E7389 (eribulin mesylate). SECONDARY OBJECTIVES: I. Estimate the measurable disease response in patients with measurable disease. II. Determine the duration of PSA and measurable disease response. III. Characterize the safety and tolerability of E7389 in these patients. OUTLINE: This study enrolled 3 cohorts of patients based on the number of prior chemotherapy regimens received. The 3 cohorts are chemonaive stratum, prior-taxane stratum, and two-prior-chemotherapy stratum. Patients receive eribulin mesylate intravenously (IV) over 5 minutes on days 1 and 8. Courses repeat every 21 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed periodically for 5 years.