Aloxi for Prevention of Chemotherapy Induced Nausea and Vomiting in Malignant Glioma Patients Receiving Irinotecan With Bevacizumab

1. Primary Objective: * To determine the efficacy and tolerability of palonosetron and dexamethasone in preventing acute CINV in brain tumor patients during the first 24 hours of receiving Irinotecan /Bevacizumab regimens. 2. Secondary Objective * To determine the safety and tolerability of palonosetron in brain tumor patients. * To determine the effects of glucocorticoid and anticonvulsants on the efficacy of palonosetron. * To determine the efficacy of palonosetron and dexamethasone in preventing delayed CINV in brain tumor patients during days 2-5. * To determine if patients receiving palonosetron have less fatigue than baseline.