ID #903 Bevacizumab treatment for NF2-associated vestibular schwannomas: a single-center experience

Introduction

Neurofibromatosis type 2 (NF2) is a rare genetic disorder characterized by the development of bilateral vestibular schwannomas, frequently associated with progressive hearing loss. Studies have showed the efficacy of the bevacizumab in controlling tumor growth and preserving hearing function, with an acceptable safety profile, leading to its approval for the treatment of NF2. We present our case series of patients with NF2-associated tumors [1] [2] .

Materials and Methods

We treated 9 patients (6 females and 3 males) with clinically and/or genetically confirmed NF2, with or without hearing loss, using intravenous bevacizumab administered every 21–28 days. Median age was 26 years (range 13–35 years). Before each administration blood tests and urine analysis were performed. All patients underwent regular audiological assessments to monitor longitudinally cochlear function.

Results

Pre-treatment, 8 patients showed vestibular schwannomas, while the remaining patient presents intracranial and spinal meningiomatosis. One patient was treated with the combination of bevacizumab and irinotecan (BEVIRI regimen). At baseline, audiometric evaluation was normal in four patients (44.4%), while five patients (55.5%) showed unilateral hearing loss. During bevacizumab, hearing function remained stable in three patients (33.3%); one patient (11.1%) experienced unilateral audiometric worsening. The remaining five patients (55.5%) showed bilateral hearing deterioration. Regarding tolerability, four patients developed proteinuria (44.4%), while one patient present both proteinuria and arterial hypertension. The patient treated with BEVIRI regimen discontinued therapy due to nephrotic-range proteinuria. One patient stopped bevacizumab for progression of disease, while in two patients dose reduction and/or prolongation of the dosing interval was necessary for proteinuria.

Conclusions

Our experience showed that a third of NF2 patients maintained stable hearing function during bevacizumab treatment. Proteinuria and arterial hypertension were the most frequent adverse events; bevacizumab appears to be a safe therapeutic option capable of preserving hearing acuity in some, but not all, NF2 patients.

1. Xing Gao et al.

2. Steffen Rosahl et al.