Eligible patients will be screened and enrolled prior to completion of post-surgical chemoradiation. Final eligibility to remain on study for safety endpoint will occur after completion of chemoradiation and prior to initiation of adjuvant TMZ regimen. Immediately post-chemoradiation and prior to initiation of cycle 1 of adjuvant TMZ, all patients will receive 500 µg of PEP-CMV vaccine weekly for a total of 3 vaccines starting 1-3 days after chemoradiation is complete. Prior to initiation of TMZ cycle 1, patients will be randomized to one of three arms (1:1:1) to receive (1) standard TMZ (200 mg/m^2/day x 5 days) with vaccination on Day 6-8 of each monthly TMZ cycle, (2) standard TMZ (200 mg/m^2/day x 5 days) with vaccination on Day 22-24 of each monthly TMZ cycle, or (3) dose-intensified TMZ (100 mg/m^2/day x 21 days) with vaccination on day 22-24 of each monthly TMZ cycle. Each cohort will have 20 patients. Up to 150 patients will be consented in order to obtain 60 evaluable patients.~The primary safety assessment for dose-limiting toxicity (DLT) will be determined one week after the third weekly vaccine. A DLT will be defined as any irreversible Grade 3 toxicity, any Grade 4 toxicity, or any life threatening-event not attributable to concomitant medication, co-morbid event, or disease progression. Initially 6 patients will be accrued to the study (2 per arm) after which accrual will be suspended to review the toxicity experienced by these patients during the first 3 weekly vaccinations. If 0 or 1 of these patients experience DLT, accrual of the remaining patients will commence. Otherwise, modifications of the protocol will be considered before accruing additional patients.~The prevalence of DLT occurring during the initial 3 weekly vaccinations or the vaccinations administered concurrently with temozolomide will be continuously monitored. If more than 25% of accrued patients experience DLT, then accrual will be suspended and reported toxicity will be carefully reviewed to determine if modifications to the protocol treatment should occur. Peptide vaccinations employing GM-CSF and Montanide ISA-51 as adjuvants have generally been well tolerated in human patients in numerous phase I-III trials.~Treatment Plan: One week after the 3rd weekly vaccination, cycles of TMZ will begin. The start of all subsequent cycles will be scheduled every 4 weeks after the first daily dose of the preceding cycle. During monthly TMZ cycles, vaccinations will occur on day 6-8 or day 22-24 of each cycle, depending on randomization arm. All vaccines will be given i.d. approximately 10cm below the inguinal ligament bilaterally. A target of six cycles with maximum of twelve cycles of TMZ may be given if the patient demonstrates continued improvement on MRI scan, decreased corticosteroid requirement, improvement in performance status, or improvement in neurologic function at the discretion of the treating neuro-oncologist. Vaccines will continue monthly after TMZ cycles until tumor progression or death.~Patients will be imaged with contrast-enhanced MRI pre & post-surgical resection (prior to initiation of chemoradiation), post-chemoradiation and prior to TMZ cycle 1, prior to TMZ cycle 4, 7 (if administered), and 10 (if administered). MRI imaging every 3 months during post-chemoradiation is preferable, but every 2 months is allowed at the discretion of the treating neuro-oncologist. MRI imaging will be conducted every 3 months after completion of TMZ for 1 year, and then every 6 months thereafter, or at frequency indicated by clinical presentation. The modified Response Assessment in Neuro-Oncology (RANO) criteria will be used for assessment of pseudoprogression and patients demonstrating definitive progression will be removed from study. Any patient removed for definitive tumor progression prior to receiving third vaccine and post vaccination immune monitoring blood draw will be replaced for safety and immunologic endpoints. Clinical endpoint comparisons will be made amongst patients successfully randomized to adjuvant TMZ treatment arms.~Blood for immune monitoring will be obtained prior to vaccines 1-4, 7 and 13, and at tumor progression. Patients seen by the Duke neuro-oncology team between these vaccine visits may have blood drawn for immune monitoring at the discretion of the study team.~As part of standard care for these patients, upon tumor progression, participants may undergo stereotactic biopsy or resection. As this is not a research procedure, consent will be obtained separately. Patients that have this procedure done here at Duke University Health System, may be approached to participate in the Duke Brain Tumor Center Biorepository study. Tissue obtained from patients who consented to the Duke Brain Tumor Center Biorepository will be used to assess immunologic cell infiltration, antigen expression, and biomarkers for immunologic response.
Eligible adult patients with new diagnosis of gliobastoma are enrolled to receive 3 weekly vaccinations of the study drug PEP-CMV 1-3 days following standard of care chemoradiation. Patients will then be randomized to one of three arms: 1). standard temozolomide (TMZ)(200mg/m^2 for 5 days) with vaccine on day 6-8 of each monthly TMZ cycle. 2). standard TMZ (200mg/m^2 for 5 days) with vaccine on day 22-24 of each monthly TMZ cycle. 3). dose-intensified TMZ (100 mg./m^2 for 21 days) with vaccine on day 22-24 of each monthly cycle. All vaccines will be given intradermally (i.d.) and will be given with monthly TMZ cycles and continue after TMZ cycles until progression or death.