Bevacizumab for Symptomatic Vestibular Schwannoma in Neurofibromatosis Type 2 (NF2)

People who have neurofibromatosis type 2 (NF2) can have tumors that grow on the auditory nerves and cause hearing loss. These tumors are called vestibular schwannomas (VSs), or acoustic neuromas. People with NF2 can also get schwannomas in other parts of their body, as well as tumors called meningiomas and ependymomas. Because VSs can cause hearing loss, many people with NF2 will have treatment to preserve their hearing. This treatment usually involves surgery. Because surgery has risks and is not able to help everyone with VSs, other methods of treatment are being explored. One area of exploration is looking to see if there is a drug that can be taken that might prevent the VSs from growing larger and causing hearing loss or brainstem compression. This study is exploring whether a drug that is approved by the FDA and is currently used to treat other tumors might also work to treat VSs. Based on people who have taken this drug to treat VSs already, there is some reason to think that it might be helpful to certain people with NF2. People enrolled in this study will receive the drug one time every three weeks for one year by infusion. This study will follow subjects over the course of the year that the person is taking the drug and for six months after the drug is stopped. This study is recruiting people who have NF2 and are currently having symptoms of tinnitus, dizziness, and/or hearing loss from their VSs. If you have NF2 and are currently having symptoms caused by your VSs, you may be eligible to participate.

PRIMARY OBJECTIVES: I. The primary objective of this study is to determine the activity of bevacizumab for treatment of symptomatic vestibular schwannomas (VS) defined as progressive hearing loss in patients with neurofibromatosis type 2 (NF2) based on objective hearing response. SECONDARY OJBECTIVES: I. Determine the safety and tolerability of bevacizumab in this patient population on an every three week dosing schedule of 7.5mg/kg for 12 months of therapy. II. Assess the rate of radiographic response (\>= 20% reduction in volume). III. Determine the growth rate of VS using volumetric MRI analysis in comparison to 1-dimensional and 2-dimensional measurements. IV. Assess changes in function of the auditory system during bevacizumab treatment. V. Assess the vascular permeability (Ktrans), relative cerebral blood volume/flow, mean transit time, and mean vessel diameter from perfusion-weighted MRI. VI. Assess the change in circulating endothelial cells, circulating progenitor cells, and plasma angiogenic proteins in subjects receiving bevacizumab treatment. VII. Observe the impact of bevacizumab on non-VS tumors in patients with NF2 via whole body MRI. VIII. Explore hearing related QOL measures throughout treatment. IX. Explore the effect of treatment with bevacizumab on auditory function using distortion product optoacoustic emissions (DPOAE) (to be evaluated at NCI only). OUTLINE: Patients receive bevacizumab intravenously (IV) over 30-90 minutes once every 3 weeks. Courses repeat every 6 weeks for up to 48 weeks in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 3 and 6 months.