Safingol and Cisplatin in Treating Patients With Locally Advanced or Metastatic Solid Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed solid tumor * Locally advanced or metastatic disease * Refractory to standard therapy OR not amenable to standard therapy * No known CNS metastasis or CNS primary PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Karnofsky 70-100% Life expectancy * At least 12 weeks Hematopoietic * Neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * WBC count ≥ 3,500/mm\^3 * Hemoglobin ≥ 9.5 g/dL * Haptoglobin ≥ 30 mg/dL * No concurrent hemolysis or history of non-drug-induced hemolysis (e.g., spherocytosis) Hepatic * AST and ALT ≤ 2.5 times upper limit of normal * Bilirubin ≤ 1.5 mg/dL * PT and PTT normal Renal * Creatinine ≤ 1.5 mg/dL Cardiovascular * No cardiac arrhythmias * No congestive heart failure * No myocardial infarction within the past 6 months Other * Not pregnant * Negative pregnancy test * No nursing during and for at least 2 months after study participation * Fertile patients must use effective contraception during and for at least 2 months after study participation * HIV negative * No mental incapacity that would preclude giving informed consent * No moderate-to-severe high-frequency hearing loss * No persistent severe (grade 2) drug-induced peripheral neuropathy * No known allergy to cisplatin or any other platinum-containing compound * No serious or uncontrolled infection * No other medical condition or reason that would preclude study participation PRIOR CONCURRENT THERAPY: Biologic therapy * At least 4 weeks since prior immunotherapy Chemotherapy * Prior cisplatin allowed * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas and mitomycin) Endocrine therapy * Not specified Radiotherapy * At least 4 weeks since prior radiotherapy Surgery * Not specified Other * Recovered from all prior therapy * No concurrent vitamins, antioxidants, herbal preparations, or supplements * Concurrent single tablet multivitamin allowed * No other concurrent investigational medications