Inclusion Criteria:

- Histologically proven diagnosis of glioblastoma or gliosarcoma (WHO grade IV)

- GBM must have unmethylated MGMT as determined by central laboratory

- Diagnosis of GBM must be made by biopsy or surgical excision, either partial or
complete; as long as there is sufficient tissue to determine MGMT status

- No prior chemotherapy or radiation for brain tumor

- Must be able to tolerate brain MRIs.

*A diagnostic contrast-enhanced MRI must be performed postoperatively within 42 days
prior to study registration.

- KPS >60.

- Age > 18

- Life expectancy of at least 3 months.

- Absolute neutrophil count > 1500/mm3, Platelets > 100,000/mm,

- Creatinine < 2 x ULN

- ALT or AST < 3 x upper limit of normal (ULN) and total bilirubin < 1.5x ULN.

- Patients with a prior history of low grade glioma who did not receive prior radiation
or chemotherapy with transformation to grade IV brain tumor are eligible.

- Women must be non-lactating, and surgically sterile, post-menopausal or have a
negative serum pregnancy test and agree to use adequate birth control. Males must
agree to use adequate birth control.

- Voluntary, signed informed consent.

Exclusion Criteria:

- Acute infection or other medical condition that would impair study treatment

- No other active invasive malignancy unless disease free for at least 3 years.

- Prior temozolomide or PPX.

- Prior use of Gliadel wafers or any other intratumoral or intracavitary treatment are
not permitted.

- Prior radiotherapy to the head or neck (except for T1 glottic cancer), resulting in
overlap of radiation fields.

- No diffuse leptomeningeal disease, or gliomatosis cerebri.

- Use of any other experimental chemotherapy drug within the 60 days prior to
randomization and during the trial. (Use of a non-chemotherapy investigational agent
must be approved by the Brown University Oncology Group)