Standard Dose Bevacizumab Versus Low Dose Bevacizumab Plus Lomustine (CCNU) for Recurrent Glioblastoma Multiforme (GBM)

The Study Drugs: Bevacizumab is designed to prevent or slow down the growth of cancer cells by blocking the growth of blood vessels. Lomustine is designed to damage the DNA (genetic material of cells) of tumor cells, which may cause the tumor cells to die. Study Groups: If you are found to be eligible to take part in this study, you will be randomly assigned (as in the flip of a coin) to 1 of 2 groups. You will have an equal chance of being in either group. * If you are in Group 1, you will receive a higher dose of bevacizumab. * If you are in Group 2, you will receive lomustine and a lower dose of bevacizumab Study Drug Administration: Each treatment cycle is 42 days. If you are in Group 1: On Days 1, 15, and 29 of every cycle, you will receive bevacizumab by vein over 90 minutes. If you are in Group 2: * On Days 1 and 22 of every cycle, you will receive bevacizumab by vein over 90 minutes. * On Day 3 of every cycle, you will take lomustine by mouth 1 time a day. You should take lomustine at bedtime 1 hour before or 2 hours after your last meal of the day with 1 cup (about 8 ounces) of water. Study Visits: If you are in Group 1 or 2, every 6 weeks: * You will be asked about any drugs you may be taking and if you have had any side effects. * You will have a physical exam, including measurement of your vital signs and weight. * You will have a neurological exam. * Your performance status will be recorded. * You will have an MRI scan. * If you are on anti-seizure drugs, blood (about 1 teaspoon) will be drawn to measure the amount of anti-seizure drugs in your blood. If you are in Group 1: * During Weeks 1-6, blood (about 3 teaspoons) drawn for routine tests 1 time a week. * After Week 6, blood (about 3 teaspoons) will be drawn for routine tests every 2 weeks. * On Weeks 2, 4, and 6, and then every 6 weeks after that, urine will be collected to check your kidney function. If you are in Group 2: * During Weeks 1-6, blood (about 3 teaspoons) drawn for routine tests 1 time a week. * After Week 6, blood (about 3 teaspoons) will be drawn for routine tests every 3 weeks. * On Weeks 3 and 6, and then every 6 weeks after that, urine will be collected to check your kidney function. Length of Study: You may stay on study treatment of lomustine and/or bevacizumab for up to 1 1/2 years. After that, you may continue taking bevacizumab for as long as the study doctor thinks it is in your best interest. You will be taken off study early if the disease gets worse or you experience intolerable side effects. End of Study Treatment Visit: After you are off study treatment, you will have an end of study treatment visit. At this visit, you may have some or all of the following tests and procedures performed: * You will be asked about any drugs you may be taking and if you have had any side effects. * You will have physical exam, including measurement of your vital signs and weight. * Blood (about 3 teaspoons) will be drawn for routine tests. * You will have a neurological exam. * Your performance status will be recorded. Long-Term Follow-up: After the end of study treatment visit, the study staff will call you every 3 months to check how you are doing. Each phone call will take about 5 minutes. This is an investigational study. Bevacizumab and lomustine are FDA approved drugs and commercially available for the treatment of brain tumors. The use of these drugs in this combination is investigational. Up to 102 participants will take part in this study. All will be enrolled at MD Anderson.