Inclusion Criteria:  The subject is at least 18 years of age The subject has the ability to understand the purposes and risks of the study and to have signed a written informed consent form approved by the investigator's IRB/Ethics Committee The subject has histologically confirmed glioblastoma The subject has progression following standard combined modality treatment with radiation and temozolomide chemotherapy The subject has an ECOG (Eastern Cooperative Oncology Group) performance status ≤ 2 The subject has a life expectancy of at least 3 months The subject has acceptable liver function: Bilirubin ≤ 1.5 times upper limit of normal AST (aspartate aminotransferase) (SGOT) and ALT (alanine transaminase 0 (SGPT) ≤ 3.0 times upper limit of normal (ULN) The subject has acceptable renal function: Serum creatinine ≤ULN The subject has acceptable hematologic status (without hematologic support): ANC (absolute neutrophil count) ≥1500 cells/uL Platelet count ≥100,000/uL Hemoglobin ≥9.0 g/dL All women of childbearing potential (not surgically sterilized or at least 1 year post-menopausal) must have a negative serum pregnancy test. Additionally, male and female subjects must agree to use effective means of contraception (surgical sterilization or the use or barrier contraception with either a condom or diaphragm in conjunction with spermicidal gel or an IUD) with their partner from entry into the study through 6 months after the last dose.  Exclusion Criteria:  The subject is receiving warfarin (or other coumarin derivatives) and is unable to switch to low molecular weight heparin (LMWH) before the first dose of study drug. The subject has evidence of acute intracranial or intratumoral hemorrhage either by MRI or computerized tomography (CT) scan. Subjects with resolving hemorrhage changes, punctate hemorrhage, or hemosiderin are eligible. The subject is unable to undergo MRI scan (eg, has pacemaker). The subject has received enzyme-inducing anti-epileptic agents within 14 days of study drug (eg, carbamazepine, phenytoin, phenobarbital, primidone). The subject has not recovered to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v5.0 Grade ≤ 1 from AEs (except alopecia, anemia and lymphopenia) due to surgery, antineoplastic agents, investigational drugs, or other medications that were administered prior to study drug. The subject has evidence of wound dehiscence. The subject is pregnant or breast-feeding. The subject has a history of cardiac disease, including arrhythmia, conduction abnormality, congenital prolonged QT syndrome, myocardial infarction, unstable angina pectoris or congestive heart failure. A prolonged QTc rhythm noted during initial ECG >480 ms. The subject has serious intercurrent illness, such as: Hypertension (two or more blood pressure [BP] readings performed at screening of > 150 mmHg systolic or > 100 mmHg diastolic) despite optimal treatment Non-healing wound, ulcer, or bone fracture Untreated hypothyroidism Unhealed rectal or peri-rectal abscess Uncontrolled active infection Stroke, or transient ischemic attack within 6 months The subject has received any of the following prior anticancer therapy: Non-standard radiation therapy such as brachytherapy, systemic radioisotope therapy (RIT), or intra-operative radiotherapy (IORT). Note: stereotactic radiosurgery (SRS) is allowed Non-bevacizumab systemic therapy (including investigational agents and small-molecule kinase inhibitors) or non-cytotoxic hormonal therapy (eg, tamoxifen) within 7 days or 5 half-lives, whichever is shorter, prior to first dose of study drug Biologic agents (antibodies, immune modulators, vaccines, cytokines) within 21 days prior to first dose of study drug Nitrosoureas or mitomycin C within 42 days, or metronomic/protracted low-dose chemotherapy within 14 days, or other cytotoxic chemotherapy within 28 days, prior to first dose of study drug Prior treatment with carmustine wafers Any history of mood disorders, psychosis or past suicide attempts Current use of SSRI (selective serotonin reuptake inhibitor), SNRI (serotonin and norepinephrine reuptake inhibitors), MAO (Monoamine oxidase) inhibitor, tramadol or trazodone; or use of these agents within 14 days of expected start of imipramine hydrochloride therapy