DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed prostate cancer

  • Metastatic disease
• Measurable and/or bony disease that has progressed despite androgen-deprivation therapy and 1 prior chemotherapy regimen for castrate metastatic disease

• Prostate specific antigen (PSA) progression

  • Must have a minimum PSA ≥ 5 ng/mL
  • At least 2 rises in PSA documented over a reference value (measure 1)
  • First rising PSA (measure 2) must be taken at least 7 days after the reference value
  • Second rising PSA (measure 3) must be taken at least 7 days after measure 2 and be greater than the second measure OR a fourth PSA (measure 4) taken is greater than the second measure

• Testosterone < 50 ng/dL

  • Must continue primary androgen deprivation with a luteinizing hormone-releasing hormone (LHRH) analogue if no prior orchiectomy
• No known brain metastases
• Treated controlled epidural disease allowed

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Life expectancy > 6 months
• WBC ≥ 3,000/mm³
• Absolute neutrophil count ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Creatinine < 2 mg/dL
• Bilirubin normal
• AST/ALT ≤ 2.5 times upper limit of normal
• Fertile patients must use effective contraception
• No New York Heart Association class III or IV heart disease
• No active angina pectoris
• No myocardial infarction within the last 6 months
• No symptomatic congestive heart failure
• No cardiac arrhythmia
• No other significant cardiovascular disease

• Patients who require additional diagnostic testing due to either history or clinical findings must meet the following additional criteria:

  • Ejection fraction > 45% by radionuclide angiocardiography (RNCA)
  • No evidence of ventricular aneurysm or other abnormal wall motion by RNCA
  • No reversible defect by stress thallium test
• No history of allergic reactions attributed to compounds of similar chemical or biologic composition to vorinostat (SAHA)
• No psychiatric illness/social situation that would limit compliance with study requirements
• No ongoing or active infection

• No other "currently active" malignancy other than nonmelanoma skin cancer

  • Patients are not considered to have a "currently active" malignancy if they have completed therapy and have no evidence of disease
• No other uncontrolled intercurrent illness

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• At least 4 weeks since prior major surgery
• At least 4 weeks since prior radiotherapy
• At least 2 weeks since prior valproic acid
• No prior radiopharmaceuticals

• No other concurrent anticancer investigational or commercial agents or therapies, including hormonal agents such as steroids, megestrol, or antiandrogens, or herbal medications

  • LHRH analogue allowed
  • Low-dose megestrol to treat hot flashes allowed

• No concurrent oral anti-androgens

  • A washout period of 4 weeks for flutamide and 6 weeks for bicalutamide or nilutamide is required if a patient has continued on antiandrogen therapy as part of combined androgen deprivation and has never had antiandrogen withdrawal despite progression on combined androgen deprivation
• No concurrent combination antiretroviral therapy for HIV-positive patients