RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die.

PURPOSE: Phase I trial to study the effectiveness of gemcitabine in treating children who have refractory solid tumors.

OBJECTIVES: I. Estimate the maximum tolerated dose of gemcitabine in children and adolescents with refractory solid tumors. II. Assess the toxicity of gemcitabine in this patient population. III. Determine the pharmacokinetic profile of gemcitabine in male and female children and adolescents. IV. Assess the antitumor activity of gemcitabine within a phase I study.

OUTLINE: This is a dose escalation study. Patients receive gemcitabine IV over 30 minutes weekly for 2 weeks. Patients achieving objective response or stable disease after 3 weeks may receive additional courses of therapy every 3 weeks in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of gemcitabine until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose limiting toxicity. Patients are followed at week 4 and then every 6 months until death.

PROJECTED ACCRUAL: Up to 30 patients will be accrued for this study over 18 months.

DISEASE CHARACTERISTICS: Histologically confirmed malignant solid tumor Confirmation made at original diagnosis No bone marrow involvement Refractory to conventional therapy and other therapies of higher priority according to CCG Phase I/II Priority List

PATIENT CHARACTERISTICS: Age: 1 to 21 Performance status: 0-2 Life expectancy: At least 2 months Hematopoietic: Absolute neutrophil count at least 1,000/mm3 Platelet count at least 100,000/mm3 (transfusion independent) Hemoglobin at least 10 g/dL (transfusions allowed) Hepatic: Bilirubin no greater than 1.5 times normal AST less than 2.5 times normal Renal: Creatinine no greater than 1.5 times normal OR Creatinine clearance or radioisotope GFR at least 70 mL/min Other: No seizure disorder Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic: At least 2 weeks since prior cytokine therapy and recovered No prior bone marrow transplantation Chemotherapy: No more than 3 prior combination or single agent chemotherapy regimens At least 3 weeks since prior chemotherapy (6 weeks since nitrosoureas) and recovered Endocrine therapy: Not specified Radiotherapy: Not specified Surgery: Not specified