G-CSF After Chemo-radiation in Patients With Glioblastoma

This is an open-label, randomized, phase II clinical study of using G-CSF in patients with newly diagnosed, MGMT-methylated, GBM treated with standard of care radiation with concurrent and adjuvant chemotherapy with temozolomide. The investigators are testing whether G-CSF can reduce the negative side effects from radiation and chemotherapy on brain health. The investigators are specifically testing the effects of G-CSF on brain structure, cognitive function, and general brain health, and the safety and tolerability of G-CSF. Participants will be randomized, stratified by age, in a 1:1 fashion to receive either standard of care chemo-radiation (chemo-RT) in combination with G-CSF, or standard of care chemo-RT without G-CSF. Treatment with G-CSF will be initiated after chemo-RT and be completed after 6 cycles of adjuvant chemotherapy with Temozolomide. This study involves screening for eligibility, standard of care radiation therapy and chemotherapy, study treatment and study visits, and follow-up visits. Participants will be in the study for up to 24 months, including 6 weeks of standard of care chemo-RT, up to 7 months of G-CSF treatment (depending on the number of additional chemotherapy cycles given as a part of standard care) and up to 7 months of active follow-up visits after study treatment ends followed by 12 months of survival follow-up. Up to 60 participants will be enrolled in this study. Granulocyte colony-stimulating factor (G-CSF) is a protein that stimulates bone marrow to produce stem cells and blood cells and release them into the bloodstream. It is known to have anti-inflammatory and neuroprotective properties (slowing or halting the loss of neurons). G-CSF is also called Filgrastim, and brand names include Granix®, Neupogen®, and Zarxio®. In addition to testing the safety and tolerability of G-CSF, the researchers in this study are testing whether or not G-CSF can protect cells in the brain or enhance repair in the brain after chemoradiation and during chemotherapy. The U.S. Food and Drug Administration (FDA) has not approved G-CSF to support brain health and cognitive function. However, G-CSF has been approved for several decades and in patients with any type of cancer who develop neutropenia (low white blood cell counts) following chemotherapy, including in patients with glioblastoma, or in patients following stem cell transplantation with low white cell blood counts. The U.S. Food and Drug Administration (FDA) has approved temozolomide as a treatment option for GBM. Temozolomide is given as standard of care chemotherapy in this study. The radiation therapy used in this study is standard of care and approved by the U.S. Food and Drug Administration (FDA) as a treatment option for GBM.