Inclusion Criteria:

1. Male or female patients 18 to 70 years
2. Histologically proven glioblastoma, WHO grade IV
3. Evidence of tumor recurrence or progression by MRI at least 3 months after radiation treatment
4. Prior radiation treatment with 60 Gy in 2-Gy fractions; concurrent daily temozolomide 75 mg/m2 daily for 42 days (max. 49 days); adjuvant temozolomide 150 - 200mg/m2 for 5 days during each 28-day cycle (max. 6 cycles)
5. Patient should have received a minimum of 2 cycles of adjuvant chemotherapy with temozolomide after concomitant regime of temozolomide and Radiotherapy
6. Patient had recovered from the effects of surgery
7. Karnofsky Performance Status of ≥70
8. Mini-Mental State Examination score >25
9. Adequate hepatic function: AST <52 U/l, ALT <50 U/l, AP ≤129 U/l
10. Adequate hematological values: neutrophils ≥1.5 x 109/l, thrombocytes ≥100 x 109/l
11. Adequate renal function: clearance <110 μmol/l
12. Written informed consent before entering the study

Exclusion Criteria:

1. Other severe underlying diseases
2. Significant renal, hepatic or bone marrow impairment
3. Pregnant women, women who are breast feeding, and women of childbearing potential who are not using chemical or mechanical contraception (prescription oral contraceptives, abstinence, condoms with spermicide, surgical sterilization, diaphragm with spermicide, or intrauterine device) or have a positive pregnancy test
4. Known Acquired Immune Deficiency Syndrome (AIDS)
5. Known hypersensitivity to temozolomide, dacarbazine or thalidomide (or any of the excipients)
6. Any concomitant drugs contraindicated for use with temozolomide (according to the product information in the Swiss drug compendium) and thalidomide (investigator's brochure, international product information).
7. Concurrent treatment with other experimental drugs or other anti-cancer therapy; treatment within a clinical trial within 30 days prior to trial entry