O6-Benzylguanine-Mediated Tumor Sensitization With Chemoprotected Autologous Stem Cell in Treating Patients With Malignant Gliomas

PRIMARY OBJECTIVES:

I. Determine the safety and feasibility of infusing autologous granulocyte colony-stimulating
factor (G-CSF) (filgrastim) mobilized stem cells transduced with a Phoenix-gibbon ape
leukemia virus (GALV)-pseudotype vector expressing methylguanine methyltransferase (MGMT)
(P140K).

II. Define the dose of BCNU (carmustine) that results in efficient engraftment of gene
modified cells when given with peripheral blood stem cell support.

SECONDARY OBJECTIVES:

I. Determine the engraftment of gene-modified cells after conditioning with BCNU.

II. Determine the ability to select gene-modified cells in vivo with this regimen.

III. Evaluate the molecular and clonal composition of gene-modified cells after chemotherapy
with temozolomide.

IV. Observe patients for clinical anti-tumor response.

V. Determine the correlation of the level of MGMT (P140K) marking with toxicity, temozolomide
dose achieved, and response.

VI. Characterize the toxicity associated with this regimen.

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

PART I: Within 35 days of surgery, patients undergo 3 dimensional (3D) conformal
intensity-modulated radiation therapy (IMRT) or proton beam radiation therapy daily 5 days
per week for 6 weeks. Patients receive filgrastim subcutaneously (SC) on days -7 to -3 and
begin stem cell collection on the 4th day of filgrastim administration (up to 3 apheresis).
Patients may also receive plerixafor SC on days -5 to -3. The CD34+ stem cells are separated
from the patient's stem cells and they are transduced with Phoenix-RD114 pseudotype vector
(retrovirus). One day after apheresis is completed, patients receive carmustine intravenously
(IV) over 3 hours followed 2 hours later by temozolomide orally (PO). At least twenty-four
hours after completion of carmustine and temozolomide, patients undergo reinfusion of
genetically-modified stem cells.

PART II: Beginning approximately 4 weeks after completion of Phase 1 of the study, patients
receive O6-benzylguanine IV continuously over 48 hours followed by temozolomide PO within 1
hour. Treatment may repeat at least every 28 days for a total of 24 courses in the absence of
disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed every 1-3 months for 2 years,
every 3-6 months for 3 years, and then annually thereafter for 10 years.

Inclusion Criteria:

- Patients with glioblastoma multiforme or gliosarcoma

- The patient or legal guardian must be able to comprehend the informed consent form and
sign prior to patient enrollment

- Karnofsky performance status at time of study entry must be >= 70%

- Life expectancy of >= 3 months

- Patients must agree to undergo repeat clinical neurological examinations and brain
magnetic resonance imaging (MRI) with appropriate contrast after every other cycle of
chemotherapy

- White blood cell (WBC) > 3000/ul

- Absolute neutrophil count (ANC) > 1500/ul

- Platelets > 100,000/ul

- Hemoglobin > 10 gm/100ml

- Total and direct bilirubin < 1.5 times upper limit of laboratory normal

- Serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate
transaminase (SGPT) =< 3 times upper limit of laboratory normal

- Alkaline phosphatase =< 3 times upper limit of laboratory normal

- Blood urea nitrogen (BUN) < 1.5 times upper limit of laboratory normal

- Serum creatinine < 1.5 times upper limit of laboratory normal

- Left ventricular ejection fraction (LVEF) >= 40%, however, subjects with a LVEF in the
range of 40-49% should have cardiology clearance prior to intervention

- MGMT promoter methylation analysis of surgically resected tumor or tumor biopsy must
demonstrate an unmethylated or hypomethylated MGMT promoter status

Exclusion Criteria:

- Patients with cardiac insufficiency and a LVEF of < 40%; history of coronary artery
disease or arrhythmia, which has required or requires ongoing treatment

- Patients with active pulmonary infection and/or pulse oximetry < 90% and a corrected
diffusion capacity of the lung for carbon monoxide (DLCO) < 70% of predicted

- Active systemic infection

- Patients who are human immunodeficiency virus (HIV) positive

- Pregnant or lactating women; a beta-human chorionic gonadotropin (HCG) level will be
obtained from women of childbearing potential; fertile men and women should use
effective contraception

- Previous chemotherapy for any malignancy including temozolomide, dacarbazine (DTIC) or
prior nitrosourea

- Diabetes mellitus

- Bleeding disorder

- Methylated or hypermethylated MGMT promoter status within tumor tissue

- Medical or psychiatric condition which in the opinion of the protocol chairman would
compromise the patient's ability to tolerate this protocol

- Prior interstitial radiotherapy, stereotactic or gamma knife surgery or implanted
BCNU-wafers