DISEASE CHARACTERISTICS:

• Histologically confirmed malignancy that is metastatic or unresectable and for which no effective standard curative or palliative therapy exists

• Brain metastases allowed provided both of the following criteria are met:

  • Received treatment for the brain metastases
  • Stable for ≥ 6 months without steroids or antiseizure medications

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2 OR
• Karnofsky 50-100%

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 times upper limit of normal (ULN) (≤ 3 mg/dL for patients with Gilbert's syndrome)
• AST/ALT no greater than 2.5 times ULN
• Albumin at least 75% of lower limit of normal

Renal:

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

Cardiovascular:

• Cardiac ejection fraction normal by MUGA
• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• Adequate oral intake
• No weight loss of more than 10% of actual body weight within the past 2 months
• No history of allergic reaction to compounds of similar chemical or biological composition to study drug
• No other uncontrolled illness
• No ongoing or active infection
• No seizure disorder
• No psychiatric illness or social situation that would preclude study compliance
• No acute or chronic gastrointestinal conditions (e.g., peptic ulcer or colitis) within the past 2 months that would interfere with drug tolerance or absorption
• Willing and able to self-administer and document doses of MS-275

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 4 weeks since prior anticancer vaccine therapy and recovered
• No concurrent immunotherapy

Chemotherapy:

• At least 4 weeks since prior anticancer chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered
• At least 8 weeks since prior UCN-01 and recovered
• No concurrent chemotherapy

Endocrine therapy:

• At least 4 weeks since prior anticancer hormonal therapy (except gonadotropin-releasing hormone [GnRH] agonists) and recovered

• Concurrent corticosteroids for physiological replacement, as antiemetic therapy, or for an ongoing condition allowed

  • Must be on a stable dose during the past 4 weeks
• No concurrent anticancer hormonal therapy except GnRH agonists for noncastrated patients with prostate cancer

Radiotherapy:

• At least 4 weeks since prior anticancer radiotherapy and recovered

• No concurrent radiotherapy

  • Concurrent localized radiotherapy to a single lesion allowed if the patient achieves at least a partial response

Surgery:

• At least 3 weeks since prior major surgery

Other:

• No other concurrent investigational or commercial antineoplastic therapies