Inclusion Criteria:

- Both of the following criteria must be satisfied:

1. Patients with newly-diagnosed pathologically-confirmed WHO Grade 3 or Grade 4
glioma (anaplastic astrocytoma, glioblastoma multiforme, gliosarcoma, anaplastic
oligodendroglioma, and anaplastic mixed glioma). Tumour histology is based on
local pathology review only;

2. Patients 18 years of age or older at time of randomization

Exclusion Criteria:

- If one or more of the following criteria are satisfied, the patient is not eligible
for the study:

1. The presence of acute or chronic DVT demonstrated by duplex ultrasonography
(DUS) or venography. (Note: a screening DUS is not required for study entry);

2. Inability to commence study drug within four weeks of original surgery or
biopsy;

3. Serious hemorrhage requiring hospitalization, transfusion, or surgical
intervention within four weeks of potential study entry;

4. Presence of a coagulopathy (e.g. INR >1.5 or platelet count < 100x109/L);

5. Symptomatic intracranial or intratumoural bleeding. (Note: post-operative
imaging of the brain is not required for study entry. Asymptomatic “routine”
post-operative blood products in a post-surgical cavity are not an exclusion;

6. Known acute (symptomatic or actively bleeding) gastroduodenal ulcer;

7. Familial bleeding diathesis;

8. Requiring long term anticoagulants for other reasons (e.g., mechanical heart
valves, atrial fibrillation);

9. Uncontrolled hypertension despite antihypertensive therapy;

10. Significant renal failure (dependent on dialysis or creatinine of greater than
three times upper limit of normal control);

11. Prior history of documented DVT or PE;

12. Allergy to anticoagulants (UFH, LMWH) including immune-mediated heparin-induced
thrombocytopenia;

13. Pregnant or of childbearing potential and not using adequate contraception;

14. Geographically inaccessible for follow-up;

15. Having an expected life span of less than 6 months;

16. Body weight < 40 kg.