18F-FDG PET and Osimertinib in Evaluating Glucose Utilization in Patients with EGFR Activated Recurrent Glioblastoma

Inclusion Criteria: * Patients must be able to provide written informed consent * Patients must have histologically proven World Health Organization (WHO) grade IV glioblastoma who have supratentorial contrast enhancing progressive or recurrent tumor by MRI imaging following standard or experimental treatment. * Patients must have measurable contrast enhancing disease with a measurement of at least 1 x 1 x 1 cm using MRI contrast imaging * Patients must have recovered from severe toxicity of prior therapy. The following intervals from previous treatments are required to be eligible: * 12 weeks from the completion of radiation * 6 weeks from a nitrosourea chemotherapy * 3 weeks from a non-nitrosourea chemotherapy * 4 weeks from any Food and Drug Administration (FDA) approved agents * 5 half-lives or 4 weeks, whichever is greater, from any investigational (not FDA-approved) agents * 4 weeks from the last treatment with bevacizumab * 2 weeks from administration of a non-cytotoxic, FDA-approved agent other than bevacizumab (e.g., hydroxychloroquine, etc.) * Patient tumor sample must have evidence of EGFR activation as determined by EGFR amplification and/or EGFR mutations by fluorescent in situ hybridization (FISH) or sequencing approaches * Patient tumor sample must not have p53 mutation * Note: Patients will be enrolled based on the documented EGFR/p53 status from the previous assays completed locally. If post enrollment evaluation of the archival tissue reve…