A PHASE I STUDY OF COMBINED RADIATION RESPONSE MODIFIERS EMPLOYING HYDROXYUREA AND PENTOXIFYLLINE FOR TREATMENT OF GLIOBLASTOMA

OBJECTIVES: I. Determine the maximum tolerated dose of pentoxifylline administered with hydroxyurea during a course of cranial radiotherapy in patients with glioblastoma multiforme. II. Determine the toxicity of this regimen in these patients. III. Measure PTX levels in plasma and CSF in order to assess whether therapeutic drug exposures (e.g., 0.4-2.0 mM/24 hours) can be achieved with an acceptable level of toxicity. IV. Assess the local control of glioblastoma in patients treated with this regimen. V. Determine the response of surrounding normal brain in patients treated with this regimen. VI. Determine the survival of patients treated with this regimen.

OUTLINE: This is a dose escalation study of pentoxifylline (PTX). Patients receive hydroxyurea (HU) and PTX IV continuously 5 days a week concurrently with cranial radiotherapy twice daily, 5 days a week, for 4 weeks in the absence of disease progression or unacceptable toxicity. The first cohort of 3 patients is treated with radiotherapy and HU alone. Subsequent cohorts of 3-6 patients receive HU and radiotherapy plus escalating doses of PTX until the maximum tolerated dose of PTX is determined or serum or CSF drug concentrations reach 0.4-2.0 mM in 6 consecutive patients with acceptable toxicity. The MTD is defined as the dose immediately preceding that at which 2 of 6 patients experience dose-limiting toxicity. Patients are followed at 1 week, at 1 and 3 months, every 3 months for 2 years, and then every 4 months for 5 years.

PROJECTED ACCRUAL: A maximum of 24-34 patients will be accrued for this study.