Effect of bevacizumab on intracranial meningiomas in patients with neurofibromatosis type 2 - a retrospective case series.

Purpose: The hallmark of neurofibromatosis type 2 (NF2) is bilateral vestibular schwannomas (VS). Approximately 80% of NF2 patients also have intracranial meningiomas. Vascular endothelial growth factor (VEGF) is expressed in both NF2-related and sporadic occurring meningiomas and anti-VEGF therapy (bevacizumab) may, therefore, be beneficial in NF2-related meningiomas. The purpose of the study was to report the effect of bevacizumab on meningiomas in NF2 patients.

Materials And Methods: We retrospectively reviewed the effect of bevacizumab on the cross-sectional area (CSA) of 14 intracranial meningiomas in 7 NF2 patients. Bevacizumab 10 mg/kg was administered intravenously every two weeks for six months and 15 mg/kg every three weeks thereafter. Patients were evaluated according to the modified Macdonald criteria with repeated magnetic resonance (MR) scans.

Results: The median duration of therapy was 27 months (range 16-34) and 42 MR scans (median 8, range 4-11) were reviewed. The median annual change in meningioma CSA prior to bevacizumab was 2% (range -4%-+76%). During treatment, a decrease in meningioma CSA was observed in 5 of 14 meningiomas (36%) in 5 of 7 patients (71%). The median decrease in CSA was -10% (range -3%--25%). One meningioma (7%) progressed and the remaining (93%) had stable disease.

Conclusions: Bevacizumab may slow or reverse the growth of some NF-related meningiomas. However, we have previously reported a fatal case of intracerebral hemorrhage following bevacizumab in NF2 patients, wherefore, this effect needs to be balanced carefully against the risk of side effects.