Abbreviated Inclusion Criteria:

        To be assessed at study enrollment prior to standard of care chemo-radiation therapy:

          -  Age ≥ 18 years.

          -  Histopathologically proven newly-diagnosed de novo GBM (WHO Grade IV glioma)

          -  The tumor must have a supratentorial component.

          -  Must have undergone definitive surgical resection of tumor with less than
             approximately 3cm x 3cm residual enhancing tumor as product of longest perpendicular
             planes by MRI.

          -  Recovery from the effects of surgery, postoperative infection, and other
             complications.

          -  Diagnostic contrast-enhanced MRI or CT scan of the brain preoperatively and
             postoperatively.

          -  Karnofsky Performance Status of ≥ 70.

          -  Signed informed consent.

          -  For females of childbearing potential, negative serum pregnancy test.

          -  Women of childbearing potential and male participants must be willing to practice
             adequate contraception throughout the study and for at least 24 weeks after the last
             dose of study drug.

        To be assessed prior to initiation of adjuvant TMZ:

          -  Must have completed RT (targeted total dose of 59.4-60.0 Gy over ≤ 7 weeks) and
             concomitant TMZ (targeted dose of 75mg/m2/d for ≤ 49 days) therapy without significant
             toxicity that persisted over 4 weeks.

          -  History & physical with neurologic examination prior to initiation of adjuvant TMZ.

          -  For patients receiving steroids, daily dose must be ≤ 4 mg.

          -  CBC with differential with adequate bone marrow function.

          -  Adequate renal function.

          -  Adequate hepatic function.

        Abbreviated Exclusion Criteria:

        To be verified in order to randomize subject:

          -  Prior invasive malignancy unless disease free for ≥ 3 years.

          -  Metastases detected below the tentorium or beyond the cranial vault and leptomeningeal
             involvement.

          -  Recurrent or multifocal malignant gliomas.

          -  HIV, Hepatitis B, or Hepatitis C seropositive.

          -  Known active infection or immunosuppressive disease.

          -  Prior chemotherapy or radiosensitizers (including Gliadel wafers) for cancers of the
             head and neck region.

          -  Prior radiotherapy to the head or neck, resulting in overlap of radiation fields.

          -  Severe, active co-morbidity.

          -  Pregnancy or women of childbearing potential and men who are sexually active and not
             willing/able to use medically acceptable forms of contraception for the entire study
             period.

          -  Pregnant or lactating women.

          -  Prior allergic reaction to temozolomide, GM-CSF or Td.

          -  Prior history of brachial neuritis or Guillain-Barré syndrome.

          -  Patients treated on any other therapeutic clinical protocols within 30 days prior to
             study entry.

        To be assessed prior to initiation of adjuvant TMZ:

          -  Did not start radiation therapy and temozolomide within 7 weeks of surgery.

          -  Progression of disease as defined by modified RANO criteria.

          -  More than 45 days after completion of radiation therapy and temozolomide