RATIONALE: Drugs used in chemotherapy, such as fluorouracil, work in different ways to stop tumor cells from dividing so they stop growing or die. Suramin may increase the effectiveness of fluorouracil by making tumor cells more sensitive to the drug.

PURPOSE: This phase I/II trial is studying the side effects and best dose of fluorouracil and the chemosensitizer suramin and to see how well they work in treating patients with metastatic renal cell (kidney) cancer.

OBJECTIVES: Phase I

Primary

• Determine the dose of suramin and fluorouracil that would result in plasma concentrations of suramin between 10-50 μM in patients with metastatic renal cell cancer.

Secondary

• Determine the preliminary efficacy of this regimen in these patients.
• Determine the pharmacokinetics of low-dose suramin in these patients. Phase II

Primary

• Determine the objective response rate (complete response and partial response) in patients treated with this regimen.

Secondary

• Determine the time to tumor progression and progress rate at 3 and 6 months in patients treated with this regimen.

OUTLINE: This is a dose-escalation phase I study followed by a phase II study.

• Phase I: Patients receive suramin IV over 30 minutes and fluorouracil IV on days 1, 8, 15, 22, 29, and 36.

Cohorts of 3-6 patients receive escalating doses suramin and fluorouracil until the dose level allowing 10-50 μM of suramin into the patient's blood is determined without 2 or more of 6 patients experiencing dose-limiting toxicity.

• Phase II: Patients receive suramin and fluorouracil (at the dose level determined in phase I) as in phase I.

In both phases, courses repeat every 8 weeks for up to 1 year in the absence of disease progression or unacceptable toxicity.

Patients are followed for survival.

PROJECTED ACCRUAL: A total of 36 patients will be accrued for this study.

• Drug: fluorouracil
• Drug: suramin

DISEASE CHARACTERISTICS:

• Histologically confirmed renal cell cancer

  • Metastatic disease

• Measurable or evaluable disease

  • Measurable disease required for phase II
• No untreated CNS metastasis or CNS metastases progressing ≤ 4 weeks after prior radiotherapy

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-1

Life expectancy

• At least 12 weeks

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 9.0 g/dL

Hepatic

• AST ≤ 2.5 times upper limit of normal (ULN)
• Alkaline phosphatase ≤ 5 times ULN
• Bilirubin ≤ 1.5 mg/dL

Renal

• Creatinine ≤ 1.8 mg/dL
• Calcium ≤ ULN
• No untreated hypercalcemia

Cardiovascular

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

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must be surgically sterile or use effective contraception
• No uncontrolled diabetes mellitus
• No known severe hypersensitivity to suramin
• No other concurrent uncontrolled illness
• No active or ongoing infection
• No active autoimmune disease
• No neuropathy ≥ grade 2
• No psychiatric illness or social situation that would preclude study compliance
• No other malignancy within the past 5 years except basal cell skin cancer, carcinoma in situ of the cervix, or localized prostate cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent filgrastim (G-CSF)

Chemotherapy

• No more than 2 prior chemotherapy regimens for renal cell cancer (phase II only)

Endocrine therapy

• No concurrent corticosteroid dose more than physiologic replacement levels

Radiotherapy

• See Disease Characteristics
• At least 4 weeks since prior radiotherapy
• No concurrent radiotherapy

Surgery

• Recovered from prior oncologic or other major surgery
• At least 4 weeks since prior major surgery
• No concurrent surgery

Other

• Recovered from all prior anticancer therapy other than alopecia (chronic toxicity < grade 2)
• At least 4 weeks since prior systemic therapy
• More than 30 days since prior investigational drugs
• Concurrent bisphosphonates allowed