Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed adenocarcinoma of the prostate

- Presence of clinically and/or radiologically documented disease (target or
non-target)

- Metastatic or locally recurrent disease for which no curative therapy exists AND for
which systemic chemotherapy is indicated due to progression, meeting the following
criteria:

- At least two rises in PSA over a reference value OR the development of new
metastatic lesions with a stable or rising PSA

- First rising PSA must be taken at least 1 week after the reference value

- Third or subsequent PSA must show further increase confirming progression
within 2 weeks prior to study enrollment

- PSA progression must be documented after discontinuation of peripheral
antiandrogens (4 weeks for flutamide and 6 weeks for
bicalutamide/nilutamide) for patients with documented evidence of
progression while receiving peripheral antiandrogens

- Medically or surgically castrated by androgen ablation

- Castrate level of testosterone (< 1.7 nmol/L) must be present for patients
undergoing medical androgen ablation

- Received prior hormone therapy

- Must have hormone-refractory disease

- Therapy with luteinizing hormone-releasing hormone (LHRH) agonist must continue
for patients already receiving this treatment at the time of enrollment

- Patients who discontinued LHRH agonist must restart therapy (if not surgically
castrated) and the castrate level of testosterone must be present

- PSA ≥ 5 ng/mL

- Primary or metastatic tumor tissue available

- No documented CNS metastases

PATIENT CHARACTERISTICS:

- ECOG performance status 0-1

- Life expectancy ≥ 12 weeks

- Absolute granulocyte count ≥ 1.5 x 10^9/L

- Platelet count ≥ 100 x 10^9/L

- AST and ALT ≤ 2.5 times upper limit of normal (ULN)

- Bilirubin normal

- Serum creatinine normal

- Potassium normal

- Calcium normal

- Fertile patients must use effective contraception

- QTc ≤ 450 msec

- LVEF ≥ 50% by Echo or MUGA scan

- Troponin I or T ≤ ULN

- Able to take oral medication

- No preexisting uncontrolled cardiac condition

- No prior myocardial infarction

- No history of other malignancies, except adequately treated nonmelanoma skin cancer
or other solid tumors curatively treated with no evidence of disease for ≥ 5 years

- No gastrointestinal abnormalities (e.g., bowel obstruction or previous gastric
resection) that would lead to inadequate absorption of HDAC Inhibitor SB939

- No known HIV positivity or hepatitis B or C infections

- No chronic medical condition or comorbidity that may increase the risks associated
with study participation/study drug administration or may interfere with the
interpretation of study results, including any of the following:

- Pulmonary disease

- Active infection

- Psychiatric condition

- Laboratory abnormality

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- At least 4 weeks since prior antiandrogens (6 weeks for bicalutamide)

- At least 4 weeks since prior external-beam radiotherapy

- Exceptions may be made for low-dose, non-myelosuppressive radiotherapy

- At least 28 days since other prior investigational therapy or anticancer therapy

- At least 14 days since prior major surgery and wound healing has occurred

- No more than 1 prior chemotherapy regimen allowed and recovered from significant
toxicity

- No prior strontium

- No prior HDAC inhibitors

- No current agents (dysrhythmic drugs) with a known risk of Torsades de Pointes

- No other concurrent cytotoxic therapy or radiotherapy

- No other concurrent investigational therapy