Inclusion Criteria:

Among other criteria, patients must meet the following conditions to be eligible for the
study:

1. Age ≥18 years of age.

2. Histologic diagnosis of glioblastoma (WHO Grade IV).

3. Previous treatment for glioblastoma must include surgery,conventional radiation
therapy and temozolomide (TMZ).

4. First or second relapse of de novo glioblastoma.

5. Screening MRI must be obtained at least 4 weeks after any salvage surgery, and at
least 12 weeks after radiation therapy.

6. KPS of ≥ 70%.

7. Life expectancy > 12 weeks.

8. Documented EGFRvIII positive tumor status by a Sponsor designated laboratory.

9. If applicable, systemic corticosteroid therapy must be at a dose of ≤ 4 mg of
dexamethasone or equivalent per day during the week prior to Day 1.

10. Evaluable disease

Exclusion Criteria:

Among other criteria, patients who meet the following conditions are NOT eligible for the
study:

1. Subjects unable to undergo an MRI with contrast.

2. History, presence, or suspicion of metastatic disease

3. Prior receipt of vaccination against EGFRvIII.

4. Any known contraindications to receipt of study drugs, including known allergy or
hypersensitivity to keyhole limpet hemocyanin (KLH), GM-CSF (sargramostim; LEUKINE®),
polysorbate 80 or yeast derived products, or a history of anaphylactic reactions to
shellfish proteins.

5. Use of non-protein based investigational therapy within 14 days prior to Day 1 or use
of antibody-based investigational therapy within 28 days prior to Day 1.

6. Clinically significant increased intracranial pressure (e.g., impending herniation),
uncontrolled seizures, or requirement for immediate palliative treatment

7. Evidence of recent hemorrhage on screening MRI of the brain

8. Evidence of current drug or alcohol abuse.