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

PRIMARY OBJECTIVES:

I. Define the test - retest variance of tumor fludeoxyglucose (FDG) uptake using double baseline 18F-FDG PET imaging (18 to 54 hours apart) in patients with EGFR activated recurrent glioblastoma.

II. After defining #1, evaluate whether osimertinib can create a statistically significant decrease in glucose utilization as determined using early, post dosing (24-72 hour) FDG-PET imaging in patients with EGFR activated recurrent glioblastoma.

SECONDARY OBJECTIVES:

I. Safety and tolerability of osimertinib in this patient population. II. Determine clinical effect of osimertinib in this patient population, as determined by 6 months progression-free survival.

III. Correlated clinical effect of osimertinib with FDG-PET results in this patient population, to define by receiver operating characteristic (ROC) analysis a clinically meaningful decrease in glucose utilization, which correlates with the clinical effect.

IV. Evaluate pharmacokinetic (PK) in this patient population using spot PK during imaging and at set time points during the study.

OUTLINE:

Within days -28 to -4, patients receive fludeoxyglucose F-18 intravenously (IV) and after 60 minutes undergo PET scan over 15 minutes. After 18-54 hours, patients undergo a second fludeoxyglucose F-18 PET scan. Patients then receive osimertinib orally (PO) once daily (QD) on days -3 to -1 and after 24-72 hours, undergo a third fludeoxyglucose F-18 PET scan. Patients then receive osimertinib PO QD on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 30 days and then every 2 months thereafter.