• 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.