Inclusion Criteria:

• All patients must have had prior pathologic confirmation of tumor histology, anaplastic glioma (AG) [anaplastic astrocytomas (AA), anaplastic oligodendrogliomas (AO) or anaplastic oligoastrocytomas (AOA)] and have supratentorial gliomas
• Patients must have shown unequivocal evidence for tumor recurrence or progression by magnetic resonance imaging (MRI) or computed tomography (CT) scan with contrast
• The recurrence to be treated needs to be the 1st or 2nd recurrence of the AG
• If a patient has had surgery prior to enrolling on study, an enhanced MRI or CT scan should be done within 96 hours prior to surgery or at least 4-6 weeks after surgery

• Patients having undergone recent resection of recurrent or progressive tumor will be eligible as long as all of the following conditions apply:

  • They are > 2 weeks from surgery
  • They have recovered from the effects of surgery
  • Evaluable or measurable disease following resection of recurrent tumor is mandated for eligibility into the study
  • To best assess the extent of residual disease post-operatively, an enhanced CT/MRI should be done no later than 96 hours after surgery or it will need to be done 4-6 weeks post-operatively; if the 96 hour scan is more than 2 weeks from registration, the scan needs to be repeated
• A baseline scan should be performed within 10 days prior to registration and on a steroid dosage that has been stable for at least 5 days otherwise a new baseline MR/CT is required; the same type of scan, i.e., MRI or CT must be used throughout the period of protocol treatment for tumor measurement
• Patients must have failed prior external beam radiation therapy; a positron emission tomography (PET) or thallium single photon emission computed tomography (SPECT), MR spectroscopy and MR Perfusion, or surgical documentation may be done at the discretion of the treating physician if there is a question of radiation changes/necrosis versus progressive disease

• Stereotactic radiosurgery (SRS):

  • Patients must have confirmation of true progressive disease rather than radiation necrosis based upon either PET or Thallium SPECT, MR spectroscopy and MR perfusion or surgical documentation of disease
  • At least 12 weeks between completion of SRS and initiation of bendamustine
• Interstitial brachytherapy: patients must have confirmation of true progressive disease rather than radiation necrosis based upon either PET or Thallium SPECT, MR spectroscopy and MR perfusion or surgical documentation of disease
• Patients must have had at least one prior chemotherapy regimen that included temozolomide and no more than one prior salvage chemotherapy
• Patients must have recovered from the toxic effects of prior therapy: 4 weeks from prior cytotoxic therapy and/or at least 2 weeks from vincristine, 6 weeks from nitrosoureas, 3 weeks from procarbazine administration, and 1 week for non-cytotoxic agents, e.g., interferon, tamoxifen, thalidomide, cis-retinoic acid, etc. (radiosensitizer does not count), 4 weeks for experimental biologic agents (epidermal growth factor receptor [EGFR] inhibitors, etc) and 7 weeks from Gliadel implantation
• All patients must sign an informed consent indicating that they are aware of the investigational nature of this study; patients must sign an authorization for the release of their protected health information
• Patients must have a life expectancy > 11 weeks
• Patients must have a Karnofsky performance status of > 60
• White blood cells (WBC) >= 3,000/ul
• Absolute neutrophil count (ANC) >= 1,500/mm^3
• Platelet count >= 80,000/mm^3
• Hemoglobin >= 9 mg/dl (NOTE: Eligibility level for hemoglobin may be reached by transfusion)
• Absolute lymphocyte count > 200/mm^3
• Serum glutamic oxaloacetic transaminase (SGOT)/serum glutamic pyruvic transaminase (SGPT) < 3 times upper limit of normal (ULN)
• Bilirubin < 1.5 times ULN
• Serum creatinine < 1.5 mg/dL
• Calculated Creatinine, glomerular filtration rate (GFR) >= 30 cc/minute

Exclusion Criteria:

• Patients must not have any significant medical illnesses that in the investigator's opinion cannot be adequately controlled with appropriate therapy or would compromise the patient's ability to tolerate this therapy
• Known human immunodeficiency virus (HIV)-positive patients receiving combination anti-retroviral therapy are excluded from the study because of possible pharmacokinetic interactions; HIV testing is not required for study participation
• Patients with a history of any other cancer (except non-melanoma skin cancer or carcinoma in-situ of the cervix), unless in complete remission and off of all therapy for that disease for a minimum of 3 years are ineligible
• Patients must not be pregnant or breast feeding and must practice adequate contraception
• Patients can only be on non-enzyme inducing anti-convulsants; if they are on an enzyme inducing anti-convulsant, they may be converted to a non-enzyme inducing anticonvulsants
• Patients cannot be taking any cytochrome P450 CYP1A2 pathway inhibiting or inducing agents (except proton pump inhibitors which are allowed) including cimetidine, antidepressants, antibiotics and all others
• Known sensitivity to bendamustine
• Known sensitivity to mannitol