Inclusion Criteria:

- Must provide independent consent or must demonstrate willingness to participate in
the study and to adhere to dose and visit schedules.

- 18 years of age or older (of either sex, and of any race)

- Histologic diagnosis of GBM or gliosarcoma with an unequivocal progression by MRI or
CT scan

- Must have received standard combined modality therapy as first-line treatment
consisting of RT plus concomitant temozolomide followed by adjuvant temozolomide (at
least 2 cycles of adjuvant temozolomide)

- Gadolinium MRI or contrast CT scan must be obtained within 14 days prior to
registration, and must be on a steroid dose that has been stable for at least 5 days.

- Karnofsky Performance status of 60 or greater

- Life expectancy of at least 8 weeks

- Recovered from the toxic effects of prior therapy, and 21 days must have elapsed
since prior treatment with temozolomide

o If a patient has residual toxicity from any previous treatment, toxicity must be ≤
Grade 1

- Laboratory tests within parameters outlined in the protocol

- Female subjects of childbearing potential & male subjects with female partner of
childbearing potential must agree to use a medically accepted method of contraception
or be surgically sterilized prior to Screening, while receiving protocol-specified
medication, and for 30 days after stopping the study medication

- Negative pregnancy test within 48 hours prior to dosing with the study drug (for
female subjects of childbearing potential)

- Free of any clinically relevant disease that would, in the Principal Investigator's
opinion, interfere with the conduct of the study or study evaluations

- Must be able to adhere to the dosing and visit schedules, and agree to record
medication times, concomitant medications, and adverse events (AEs) accurately and
consistently in a daily diary

- Unstained slides (at least 15 of 10 micron thickness, or 20 when < 10 micron
thickness)or 1 tissue block must be available from the original diagnostic
biopsy/surgery or from the biopsy/surgery recurrence

- Participants who have undergone recent resection of recurrent or progressive tumor
will be eligible provided at least 2 weeks has elapsed since surgery, and subjects
have recovered from surgical-related trauma

- Residual disease following resection of recurrent GBM or gliosarcoma is not mandated
for eligibility into the study.

Exclusion Criteria:

- Participant has received a dosing schedule of temozolomide other than 75 mg/m2/day
for 42 days during RT followed by adjuvant temozolomide at a dose of 150-200
mg/m2/day for 5 days of a 28-day schedule (standard dose adjustments for toxicity are
allowed)

- Any other anti-tumor agent other than standard surgical resection, RT and
temozolomide prior to enrollment or during the study period

- Received treatment with BCNU (Gliadel) wafers or GliaSite

- Progressed prior to receiving at least 2 cycles of adjuvant temozolomide

- Pregnant or intending to become pregnant during the study

- In a situation or condition that, in the opinion of the Investigator, may interfere
with optimal participation in the study

- Participating in any other clinical study in which an investigational drug is
prescribed

- Allergic to or has sensitivity to the study drug or its excipients

- History of any other cancer (except non-melanoma skin cancer or carcinoma in situ of
the cervix), unless he/she is in complete remission and has not received treatment
for that particular disease for the past 3 or more years