Atypical and anaplastic meningiomas treated with bevacizumab

Atypical and anaplastic (WHO Grades II and III) meningiomas are aggressive tumors, and patients often progress despite surgery and radiation. There is no known effective chemotherapeutic option for these patients. Meningiomas have a high expression of vascular endothelial growth factor receptor (VEGFR). We sought to retrospectively study the activity of bevacizumab, which is an anti-angiogenic agent targeting the VEGF pathway in these tumors. This is a retrospective review of WHO Grade II and III meningiomas treated at four institutions, selecting only those patients who received bevacizumab. We analyzed radiographic response according to standard RANO criteria, progression-free survival (PFS) and overall survival from the initiation of bevacizumab therapy using Kaplan-Meier statistics. We identified 15 patients across four institutions who carried a diagnosis of atypical or anaplastic meningioma and were treated with bevacizumab. Best radiographic response was stable disease. MR perfusion studies showed decreased tumor blood volume in one patient. Three patients developed non-fatal intratumoral hemorrhage. Median PFS was 26 weeks (95 % CI, 10-29 weeks). Six month PFS rate was 43.8 % (95 % CI, 15.7-69.1 %). Bevacizumab was well-tolerated in our patients, and may be considered in patients who have exhausted radiation and surgical options. Prospective studies are required to define the safety and efficacy of bevacizumab in atypical and anaplastic meningiomas.