Bevacizumab treatment can result in
tumor shrinkage of progressive
vestibular schwannomas in some
neurofibromatosis 2 (NF2) patients but its effect on
meningiomas has not been defined. To determine the clinical activity of
bevacizumab against NF2-related
meningiomas, we measured changes in volume of
meningiomas in NF2 patients who received
bevacizumab for treatment of progressive
vestibular schwannomas. A radiographic response was defined as a 20% decrease in
tumor size by volumetric MRI analysis. In addition, we determined the expression pattern of
growth factors associated with
tumor angiogenesis in
paraffin-embedded tissues from 26 unrelated
meningiomas. A total of 48
meningiomas in 15 NF2 patients were included in this study with a median follow up time of 18 months. A volumetric radiographic response was seen in 29% of the
meningiomas (14/48).
Tumor shrinkage was not durable: the median duration of response was 3.7 months and the median time to progression was 15 months. There was no significant correlation between pre-treatment growth rate and
meningioma response in regression models. Tissue analysis showed no correlation between
tumor microvascular density and expression of
VEGF pathway components. This data suggests that, in contrast to
schwannomas, activation of
VEGF pathway is not the primary driver of angiogenesis in
meningiomas. Our results suggest that a minority of NF2-associated
meningiomas shrink during
bevacizumab therapy and that these responses were of short duration. These results are comparable to previous studies of
bevacizumab in sporadic
meningiomas.