Hearing and facial function outcomes for neurofibromatosis 2 clinical trials

Objectives: Vestibular schwannomas are the hallmark of neurofibromatosis 2 (NF2), occurring in > 95% of patients. These tumors develop on the vestibulocochlear nerve and are associated with significant morbidity due to hearing loss, tinnitus, imbalance, facial weakness, and risk of early mortality from brainstem compression. Although hearing loss and facial weakness have been identified as important functional outcomes for patients with NF2, there is a lack of consensus regarding appropriate endpoints in clinical trials. Methods: The functional outcomes group reviewed existing endpoints for hearing and facial function and developed consensus recommendations for response evaluation in NF2 clinical trials. Results: For hearing endpoints, the functional group endorsed the use of maximum word recognition score as a primary endpoint, with the 95% critical difference as primary hearing outcomes. The group recommended use of the scaled measurement of improvement in lip excursion (SMILE) system for studies of facial function. Conclusions: These recommendations are intended to provide researchers with a common set of endpoints for use in clinical trials of patients with NF2. The use of common endpoints should improve the quality of clinical trials and foster comparison among studies for hearing loss and facial weakness.