Bevacizumab treatment for symptomatic spinal ependymomas in neurofibromatosis type 2.

Abstract

Neurofibromatosis type 2 (NF2) is a tumor suppressor syndrome associated with vestibular schwannomas, meningiomas, and spinal ependymomas. There have been anecdotal reports of radiographic response of spinal ependymomas in NF2 patients being treated for progressive vestibular schwannomas with bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF). The aim of this study was to review the clinical effects of bevacizumab treatment for symptomatic, NF2-associated ependymomas We conducted a retrospective review of all patients with NF2 treated with bevacizumab for symptomatic ependymoma at three NF2 specialty centers. Tumor size was evaluated by linear measurements; radiographic response was defined as >20% reduction in tumor size. We also performed immunohistochemical evaluation of NF2-associated symptomatic ependymomas from five patients, including two from this clinical series. Eight patients with NF2 and symptomatic ependymoma were treated with bevacizumab. All patients had subjective clinical improvement with bevacizumab, although only five of eight patients evaluated had radiographic response. All tumors expressed VEGF-R2. Four of five evaluated ependymomas expressed VEGF-R1; one without VEGF-R1 expression was from a patient who showed clinical but not radiographic response. Treatment using bevacizumab improved symptoms related to NF2-associated ependymomas, often without concurrent radiographic response. This treatment effect may be related to VEGF-R1 expression in NF2-associated ependymoma.