-Patients will be treated with bevacizumab by intravenous injection at a dose of 10mg/kg and irinotecan at a dose of 125 mg/m^2 for patients on non-enzyme-inducing anti-epileptic drugs (NEIAED) and 340 mg/m^2 for patients on enzyme-inducing anti-epileptic drugs (EIAED) every two weeks on a 4-week cycle.