Bevacizumab treatment for vestibular schwannoma in a patient with neurofibromatosis type 2: hearing improvement and tumor shrinkage
Neurofibromatosis type 2 (NF2) is a dominantly inherited genetic condition that clinically manifests through the appearance of multiple meningiomas, ependymomas and bilateral vestibular schwannomas (acoustic neuromas) which lead to progressive hearing loss. Neovascularization is necessary for tumor growth and is driven by tumor-produced angiogenic factors such as vascular endothelial growth factor (VEGF). Bevacizumab is a humanized monoclonal antibody that neutralizes the activity of VEGF. Recent data have shown that VEGF is produced by schwannoma tumor cells. Bevacizumab treatment in patients with NF2 who were considered poor candidates for surgery and radiation therapy was found to result in clinically meaningful hearing improvement and tumor volume reduction in previous studies. We report the case of a 40-year-old woman with sudden right-sided hearing loss. Magnetic resonance imaging (MRI) revealed multiple meningiomas and neurinomas (C2 and L5 lesions) and a right-sided acoustic neurinoma, confirming the diagnosis of NF2. Bevacizumab was given as infusion every 2 weeks at a dose of 5.0 mg/kg body weight with MRI monitoring every 6 months. After 6 months from the start of therapy the patient reported progressive improvement of hearing response in audiometry, word recognition and face-to-face conversation. MRI evidenced reduction of the volume of the right vestibular schwannoma and the multiple meningiomas as well as attenuation of brain stem compression. At the time of writing the patient is continuing treatment with bevacizumab without adverse events. She has good functional status and quality of life.