Temozolomide (TMZ) is the chemotherapy drug approved by the FDA to increase survival in glioblastoma (GBM) patients beyond surgical resection and radiation therapy alone. Give its activity in astrocytomas, TMZ is commonly used in grade III anaplastic astrocytoma (AA) as well. Both grade III AA and grade IV GBM are high grade gliomas (HGG). The short half-life of this drug and known oscillations in DNA damage repair make it an ideal candidate for chronotherapy.