Phase 0 With Expansion Phase Clinical Trial of Quisinostat Plus Radiotherapy in Newly-diagnosed and Recurrent Grade 4 IDH-Wildtype Glioblastomas

Eligible participants (rGBM in Arm A and nGBM in Arm B) will enroll in the Phase 0 study and receive quisinostat prior to a planned resection. Arm A includes a 3+3 design to determine optimal time interval (OTI) of final dose prior to surgery. Further rGBM participants and nGBM participants will enroll at OTI once established. Blood, tumor, and cerebrospinal fluid (CSF) samples will be collected during surgery, and blood and CSF samples will be collected after surgery, to measure the amount of drug that is present in the samples. Participants with tumors demonstrating PK response will continue with therapeutic dosing of quisinostat treatment on Monday, Wednesday, Friday of 5-day cycles after surgery concurrently with their standard of care (SOC) fractionated RT. Participants will continue to receive quisinostat and SOC RT for their physician-directed duration of RT, (2-3 weeks for rGBM and 5-6 weeks form nGBM). The Phase 0 Primary Objective is to evaluate concentration of quisinostat in gadolinium-non-enhancing tumor tissue, and the Expansion Phase Primary Objective is to determine the 6-month progression free survival (PFS6) rate in rGBM participants who had positive PK response in Phase 0. The Phase 0 Secondary Objective is to evaluate concentration of quisinostat in CSF, and the Expansion Phase Secondary Objectives are to monitor safety and tolerability of quisinostat and examine overall survival (OS) in participants.