Inclusion Criteria:

• Patients with vestibular schwannoma and/or meningioma diagnosed by MRI where surgical resection has been selected as treatment
• Patients diagnosed with NF2 must meet Manchester Criteria
• Age > 18 years
• Prior biologic therapy, chemotherapy, surgery or radiation is permitted
• At the time of screening, the patient must have normal organ and marrow function
• Eastern Cooperative Oncology Group/World Health Organization (ECOG/WHO) performance status of 0-1
• Patients must be able to swallow capsules
• Patients or their legal representatives must be able to read, understand and provide informed consent to participate in the trial
• Tumor type will be confirmed by a neuropathologist
• Females of childbearing potential must have a negative serum or urine pregnancy test with a sensitivity of at least 50 mIU/mL prior to starting AR-42
• The patient must be willing to comply with fertility requirements

Exclusion Criteria

• Pregnant women are excluded from this study because the potential for teratogenic or abortifacient effects of AR-42 are not known
• There is an unknown but potential risk for AEs in nursing infants secondary to treatment of the mother with AR-42, breastfeeding should be discontinued if the mother is treated with AR-42
• Pediatric patients are excluded from the phase 0 study as the effects of AR-42 are not known on children and there is no potential direct benefit to them
• Patients with malabsorption or any other condition that in the opinion of the principal investigator could cause difficulty in absorption of drug
• Patients requiring chronic corticosteroids (dose equivalent > 20mg prednisolone)
• Concurrent use of complementary or alternative medicines that in the opinion of the principal investigator would confound the interpretation of toxicities and/or antitumor activity of the study drug
• Patients with a "currently active" second malignancy that, in the opinion of the principal investigator, will interfere with patient participation, increase patient risk, or confound data interpretation
• Patients with a mean QTcB > 450 msec in males and > 470 msec in females
• Patients with long QT syndrome
• Patients who are being treated for an active infection
• Patients receiving the following concomitant medications
  • Any other anti-neoplastic chemotherapy or biologic therapy during the study
  • Concomitant radiotherapy
  • Concomitant HDAC inhibitors (e.g. valproic acid) as class-specific adverse reactions may be additive
  • Use of granulocyte colony-stimulating factors including G-CSF, pegylated G-CSF or GM-CSF should follow ASCO guidelines for patients receiving anti-cancer therapy
  • Drugs associated with QT/QTc prolongation (see Appendix A)
• Patients who are receiving concurrent anti-neoplastic therapy
• Any other medical condition, including mental illness or substance abuse, deemed by the principal investigator to likely interfere with a patient's ability to sign informed consent, cooperate and participate in the study, or interfere with the interpretation of the results
• Patients with significant cardiovascular disease, including a myocardial infarction or unstable angina within 6 months or unstable cardiac arrhythmias are not eligible for the study
• Known HIV infection, as their immunosuppressive conditions may complicate potential pancytopenias seen with HDAC inhibitors and complicate evaluation of drug effect