Inclusion Criteria:

        Patients must meet all of the following inclusion criteria to be eligible for participation
        in this study:

          -  Surgical or biopsy-proven diagnosis of WHO grade 3 AA.

          -  First AA tumor progression or recurrence ≤ 6 months prior to randomization based on
             MRI using T2 hyperintesity, gadolinium (Gd)-contrast enhancement, or both. To avoid
             enrollment of patients with glioblastoma, patients with Gd-contrast enhancing tumors
             will be eligible if there is no necrosis seen on MRI and any of the following criteria
             is true:

               1. Gd-contrast lesion margins are not clearly defined,

               2. Gd-contrast lesions are only measurable in one dimension,

               3. Gd-contrast lesion has two perpendicular diameters less than 10 mm,

               4. Gd-contrast lesion has two perpendicular diameters greater than 10 mm but less
                  than 20 mm and lesion does not demonstrate central necrosis,

               5. Recent histopathological confirmation of WHO grade 3 AA

          -  Received EBRT and temozolomide chemotherapy prior to first tumor progression or
             recurrence of WHO Grade 3 AA.

          -  Completion of EBRT ≥ 6 months prior to randomization.

          -  A patient whose AA tumor has progressed or recurred and has had another surgical
             resection prior to randomization will be eligible if a) pathology review confirms AA,
             and b) post-surgical MRI demonstrates measurable tumor on T2 FLAIR.

          -  Karnofsky Performance Status (KPS) score of ≥ 70.

        Exclusion Criteria:

        Patients who meet any of the following exclusion criteria are not eligible for study
        participation:

          -  MRI defining progression is consistent with a diagnosis of glioblastoma or radiation
             necrosis.

          -  Patients who are considered to be refractory to EBRT and temozolomide but who have not
             progressed.

          -  Prior systemic therapy for recurrence of AA.

          -  Presence of extracranial or leptomeningeal disease.

          -  Prior lomustine use.

          -  Any other clinical condition or prior therapy that, in the opinion of the
             Investigator, would make the patient unsuitable for the study.

          -  Pregnant or breastfeeding.