A Trial of One-week on/One-week Off Temozolomide Versus Continuous Dose-Intense Temozolomide in Patients With Glioblastoma Multiforme at First Relapse

Inclusion Criteria: 1. Participants must have histopathologically-confirmed, supratentorial, glioblastoma. 2. Participants must have received first-line treatment regimen consisting of RT plus concomitant temozolomide followed by adjuvant temozolomide. 3. Participants must be first recurrence or progression of glioblastoma after first-line treatment regimen. 4. Participants must have demonstration of recurrent disease on MRI following prior therapy. 5. Participants must have bi-dimensionally measurable disease with a minimum measurement of 1 cm in one dimension on MRI performed within 14 days prior to first treatment. If receiving corticosteroids, participants must be on a stable or decreasing dose of corticosteroids for at least 5 days prior to baseline MRI. 6. Participants must have developed progressive disease after receiving prior therapy and must have an interval of at least 12 weeks from the completion of radiation and concomitant temozolomide therapy to study entry (unless progressive tumor growth is outside the radiation field or there is histopathological confirmation of recurrent tumor) 7. Age 18-75 years old. 8. Life expectancy of at least 12 weeks. 9. Karnofsky performance status at least 60 10. Participants must be able to adhere to the dosing and visit schedules, and agree to record medication times, concomitant medications, and adverse events (AEs) accurately and consistently in a daily diary. 11. 20 paraffinsections of glioblastoma tissue must be available. 12. Participants must have normal organ and marrow function as defined below: leukocytes \>4.0×10\^9/L，platelets \>100×10\^9/L，Hemoglobin \> 10 g/dl，Serum creatinine\< 1.5-fold upper normal range，AST and ALT \<2-fold upper normal range, Alkaline phosphatase \< 3-fold upper normal range. 13. Female and male subjects of childbearing potential must agree to use a medically accepted method of adequate contraception. Exclusion Criteria: 1. Treatment with any chemotherapy other than temozolomide prior to enrollment. 2. Progressive or recurrent glioblastoma documented by MRI earlier than 12 weeks after completion of radiotherapy. 3. History of any other cancer. 4. HIV infection. 5. Women who are pregnant or breast feeding.