DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed adenocarcinoma of the prostate

• Biochemical recurrence

  • Rising prostate-specific antigen (PSA) of at least 2.0 ng/mL following a nadir after local curative therapy (radical prostatectomy and/or pelvic radiotherapy)

    • Rising PSA must be confirmed by 2 consecutive increases measured at least 2 weeks apart
• No evidence of local or distant relapse by physical exam or radiography

• No clinical or radiographic evidence of metastatic disease by all of the following:

  • CT scan or MRI of the pelvis
  • Bone scan
  • Posterior, anterior, and lateral x-ray

PATIENT CHARACTERISTICS:

Age

• Over 18

Performance status

• Karnofsky 60-100%

Life expectancy

• More than 3 months

Hematopoietic

• WBC at least 3,000/mm^3
• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic

• Bilirubin no greater than 1.5 mg/dL
• AST and ALT no greater than 2.5 times upper limit of normal

Renal

• Creatinine normal OR
• Creatinine clearance at least 60 mL/min

Cardiovascular

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other

• Fertile patients must use effective contraception
• No history of allergic reactions attributed to compounds of similar chemical or biological composition to perifosine
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ, or adequately treated stage I or II cancer currently in complete remission
• No ongoing or active infection
• No other concurrent uncontrolled illness
• No psychiatric illness or social situation that would preclude study compliance

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 6 months since prior vaccine therapy
• No concurrent biological response modifiers

Chemotherapy

• No prior cytotoxic chemotherapy
• No other concurrent chemotherapy

Endocrine therapy

• Prior adjuvant or neoadjuvant hormonal therapy allowed provided treatment duration was no longer than 9 months*
• At least 1 year since prior neoadjuvant or adjuvant androgen deprivation therapy*
• No concurrent corticosteroids
• No concurrent hormonal therapy NOTE: *No rising PSA at the time therapy was discontinued

Radiotherapy

• See Disease Characteristics
• No concurrent radiotherapy

Surgery

• See Disease Characteristics

Other

• No other concurrent investigational agents
• No other concurrent anticancer agents or therapies (investigational or commercial)
• No concurrent complementary or alternative therapy (e.g., Hypericum perforatum [St. John's Wort], PC-SPES, or any other herbal remedy for the treatment of prostate cancer)
• No concurrent combination antiretroviral therapy for HIV-positive patients