ILX23-7553 in Treating Patients With Solid Tumors That Have Not Responded to Previous Therapy

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed solid tumor refractory to conventional therapy or for which no standard therapy exists Measurable or evaluable disease PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9.0 g/dL Hepatic: Bilirubin no greater than 2.0 mg/dL (regardless of liver metastases) SGOT/SGPT no greater than 2 times upper limit of normal Renal: Creatinine no greater than 1.5 mg/dL Calcium no greater than 9.5 mg/dL No nephrocalcinosis Cardiovascular: No congestive heart failure No angina or ischemia Other: Ability to swallow or nasogastric or gastrostomy tube present Adequate organ and immune system function No known hypersensitivity to ILX23-7553 or analogues HIV negative No active uncontrolled infection No other severe disease or psychiatric disorder that would preclude study Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks since nitrosoureas or mitomycin) and recovered No concurrent curative antineoplastic drugs Endocrine therapy: Not specified Radiotherapy: At least 4 weeks since prior radiotherapy and recovered No concurrent curative radiotherapy Surgery: At least 4 weeks since prior surgery and recovered Other: At least 30 days since prior investigational agents At least 2 weeks since prior vitamin D, calcium supplementation, or cholestyramine No concurrent vitamin D, calcium supplementation, or cholestyramine No concurrent digoxin No concurrent hypercalcemia therapy (i.e., biphosphonates or insulin)