Combination Chemotherapy Plus Gene Therapy in Treating Patients With CNS Tumors

OBJECTIVES: I. Determine the toxicity (detection of replication competent retrovirus) associated with CD34+ cells transduced with a retroviral vector expressing human O6-methylguanine DNA methyltransferase in adult and pediatric patients with poor prognosis CNS tumors. II. Determine the safety of genetic modification of cells carried out in the presence (ex vivo) of recombinant fibronectin (FN) fragment utilized to assist in retroviral entry into mammalian cells. III. Determine any evidence of engraftment of cells exposed to FN during retroviral transduction. IV. Determine any evidence of antibodies to FN following infusion of cells exposed to FN during ex vivo retroviral transduction. OUTLINE: Patients with surgically approachable lesions undergo maximal surgical debulking that allows preservation of good neurologic functioning. Harvest: Patients receive filgrastim (G-CSF) subcutaneously or IV beginning 4 days prior to initiation of first leukapheresis and continuing until completion of harvest. Peripheral blood stem cells are harvested and selected for CD34+ cells which are transduced with a fibronectin assisted retroviral vector expressing human O6-methylguanine DNA methyltransferase. Intensification: Patients receive oral lomustine and vincristine IV on day 0 and oral procarbazine on days 1-7. Treatment repeats every 4 weeks for 4 courses in the absence of disease progression or unacceptable toxicity. Patients with newly diagnosed tumors may undergo involved field radiotherapy (IF-RT) after completion of the third course of chemotherapy and may begin the fourth course of chemotherapy after completion of IF-RT. Transplantation: Two-thirds of the transduced CD34+ cells are reinfused on day 9 of the first course of chemotherapy. The remaining portion (one-third) of the transduced CD34+ cells are reinfused on day 9 of the second course of chemotherapy. Untransduced CD34+ cells are reinfused on day 9 of the last 3 courses of chemotherapy. Patients are followed every 3 months for 6 months, every 4 months for 1 year, every 6 months through year 5, and then annually thereafter. PROJECTED ACCRUAL: Approximately 15-20 patients will be accrued for this study within 1 year.