Venous Thromboembolism Prevention in Outpatients With Glioma

This study is testing a blood-thinning medication (apixaban) to prevent dangerous blood clots in the legs or lungs in people who have been diagnosed with a high-grade brain tumor called glioma and are receiving radiation and chemotherapy. **You may be eligible if...** - You are 18 or older - You have been diagnosed with a high-grade glioma (WHO grade 4, such as glioblastoma) confirmed by biopsy or surgery - You are planning to receive radiation therapy and chemotherapy - Your blood counts and kidney function are within acceptable ranges - You are reasonably functional (Karnofsky score 60–100) **You may NOT be eligible if...** - You have had a blood clot (deep vein thrombosis, pulmonary embolism, or brain vein clot) in the past 6 months - You are currently on other blood thinners - You are pregnant - You have had significant recent bleeding, brain bleeding, or major surgery within 48 hours - You have an allergy to apixaban or are on medications that interact with it Talk to your doctor to see if this trial is right for you.