Bevacizumab Treatment for Vestibular Schwannoma in a Patient with Neurofibromatosis Type 2: Hearing Improvement and Tumor Shrinkage

Bevacizumab Treatment for Patients with NF2-Related Schwannomatosis: A Single Center Experience

(1) Background: NF2-related schwannomatosis, characterized by the development of bilateral vestibular schwannomas, often necessitates varied treatment approaches. Bevacizumab, though widely utilized, demonstrates variable effectiveness on hearing and tumor growth. At the same time, (serious) adverse events have been frequently reported. (2) Methods: A single center retrospective study was conducted, on NF2-related schwannomatosis patients treated with bevacizumab from 2013 to 2023, with the aim to assess treatment-related and clinical outcomes. Outcomes of interest comprised hearing, radiologic response, symptoms, and adverse events. (3) Results: Seventeen patients received 7.5 mg/kg bevacizumab for 7.1 months. Following treatment, 40% of the patients experienced hearing improvement, 53%, stable hearing, and 7%, hearing loss. Vestibular schwannoma regression occurred in 31%, and 69% remained stable. Further symptomatic improvement was reported by 41%, stable symptoms by 47%, and worsened symptoms by 12%. Treatment discontinuation due to adverse events was observed in 29% of cases. Hypertension (82%) and fatigue (29%) were most frequently reported, with no occurrences of grade 4/5 toxicities. (4) Conclusion: Supporting previous studies, bevacizumab demonstrated positive effects on hearing, tumor control, and symptoms in NF2-related schwannomatosis, albeit with common adverse events. Therefore, careful consideration of an appropriate management strategy is warranted.

Multicenter, prospective, phase II study of maintenance bevacizumab for children and adults with NF2-related schwannomatosis and progressive vestibular schwannoma

BACKGROUND

Prospective data on maintenance therapy with bevacizumab for persons with NF2-related schwannomatosis (NF2-SWN) is lacking. In this prospective multicenter phase II study, we evaluated the efficacy, safety, and tolerability of bevacizumab for maintenance therapy in children and adults with NF2-SWN and hearing loss due to vestibular schwannomas (VS).

METHODS

Following induction therapy, participants received bevacizumab 5 mg/kg every 3 weeks for 18 months. Participants were monitored for changes in hearing, tumor size, and quality of life (QOL), and for adverse events. Hearing loss was defined as a statistically significant decline in word recognition score (WRS) or pure-tone average compared to the study baseline; tumor growth was defined as >20% increase in volume compared to baseline.

RESULTS

Twenty participants with NF2-SWN (median age 23.5 years; range, 12.5-62.5 years) with hearing loss in the target ear (median WRS 70%, range 2%-94%) received maintenance bevacizumab. Freedom from hearing loss in the target ear was 95% after 48 weeks, 89% after 72 weeks, and 70% after 98 weeks. Freedom from tumor growth in the target VS was 94% after 48 weeks, 89% after 72 weeks, and 89% after 98 weeks. NF2-related QOL remained stable for 98 weeks whereas tinnitus-related distress decreased. Maintenance bevacizumab was well tolerated, with 3 participants (15%) discontinuing treatment due to adverse events.

CONCLUSIONS

Maintenance bevacizumab (5 mg/kg every 3 weeks) is associated with high rates of hearing and tumor stability during 18 months of follow-up. No new unexpected adverse events related to bevacizumab were identified in this population.

Withdrawal of bevacizumab is associated with rebound growth of vestibular schwannomas in neurofibromatosis type 2-related schwannomatosis patients

Background

Neurofibromatosis type 2 (NF2)-related schwannomatosis is an autosomal dominant tumor-predisposition syndrome characterized by bilateral vestibular schwannomas (VS). In patients with VS associated with NF2, vascular endothelial growth factor A inhibitor, bevacizumab, is a systemic treatment option. The aim of this study is to retrospectively evaluate NF2 patient responses to bevacizumab on VS growth and symptom progression.

Methods

This is a retrospective analysis of patients seen at the Mayo Clinic Rochester Multidisciplinary NF2 Clinic.

Results

Out of 76 patients with NF2 evaluated between 2020 and 2022, we identified 19 that received treatment with bevacizumab. Thirteen of these patients discontinued bevacizumab after median treatment duration of 12.2 months. The remaining 6 patients are currently receiving bevacizumab treatment for a median duration of 9.4 months as of March, 2023. Fifteen patients had evaluable brain MRI data, which demonstrated partial responses in 5 patients, stable disease in 8, and progression in 2. Within 6 months of bevacizumab discontinuation, 5 patients had rebound growth of their VS greater than 20% from their previous tumor volume, while 3 did not. Three patients with rebound growth went on to have surgery or irradiation for VS management.

Conclusions

Our single-institution experience confirms prior studies that bevacizumab can control progression of VS and symptoms associated with VS growth. However, we note that there is the potential for rapid VS growth following bevacizumab discontinuation, for which we propose heightened surveillance imaging and symptom monitoring for at least 6 months upon stopping anti-VEGF therapy.

Rationale and Design of BeatNF2 Trial: A Clinical Trial to Assess the Efficacy and Safety of Bevacizumab in Patients with Neurofibromatosis Type 2 Related Vestibular Schwannoma

Simple Summary

Neurofibromatosis type 2 (NF2) is a rare genetic hereditary disease characterized by multiple central nervous system tumors, most frequently bilateral vestibular schwannomas (VSs). No chemotherapeutic agents are available for clinical use, and surgery and radiotherapy are the only therapeutic options available now. Still, neither treatment option alleviates hearing loss in patients with NF2 and VS; they may even exacerbate it. However, bevacizumab has been reported to be effective in suppressing the tumor’s growth and has shown unprecedented efficacy in improving hearing. We describe a new ongoing and novel clinical trial, BeatNF2, a randomized, double-blinded, placebo-controlled, multicenter trial to assess bevacizumab’s efficacy and safety in patients with NF2. The study’s primary endpoint is improved hearing function 24 weeks after the beginning of the treatment protocol.

Abstract

Neurofibromatosis type 2 (NF2) causes bilateral vestibular schwannomas (VSs), leading to deafness. VS is treated by surgery or radiation, but neither treatments prevent hearing loss. Bevacizumab was found to be effective in suppressing the tumor’s growth and may help to improve hearing. We are conducting a randomized, double-blind, multicenter clinical trial to verify the efficacy and safety of bevacizumab in NF2-related VS. The primary objective is to evaluate the efficacy of bevacizumab in improving hearing in the affected ear. One of the secondary objectives is to evaluate bevacizumab’s efficacy in rechallenge treatment in relapsed cases. Sixty patients will randomly receive either bevacizumab or a placebo and will be clinically observed for 48 weeks in the initial intervention phase. In the first half (24 weeks), they will receive either 5 mg/kg of bevacizumab or a placebo drug. In the second half, all patients will receive 5 mg/kg of bevacizumab. If hearing function deteriorated in a patient who had shown improvement during the first phase, a rechallenge dose with bevacizumab would be offered.

Multicenter, Prospective, Phase II and Biomarker Study of High-Dose Bevacizumab as Induction Therapy in Patients With Neurofibromatosis Type 2 and Progressive Vestibular Schwannoma

PURPOSE

Bevacizumab treatment at 7.5 mg/kg every 3 weeks results in improved hearing in approximately 35%-40% of patients with neurofibromatosis type 2 (NF2) and progressive vestibular schwannomas (VSs). However, the optimal dose is unknown. In this multicenter phase II and biomarker study, we evaluated the efficacy and safety of high-dose bevacizumab in pediatric and adult patients with NF2 with progressive VS.

PATIENTS AND METHODS

Bevacizumab was given for 6 months at 10 mg/kg every 2 weeks, followed by 18 months at 5 mg/kg every 3 weeks. The primary end point was hearing response defined by word recognition score (WRS) at 6 months. Secondary end points included toxicity, radiographic response, quality of life (QOL), and plasma biomarkers.

RESULTS

Twenty-two participants with NF2 (median age, 23 years) with progressive hearing loss in the target ear (median baseline WRS, 53%) were enrolled. Nine (41%) of 22 participants achieved a hearing response at 6 months (1 of 7 children and 8 of 15 adults; P = .08). Radiographic response was seen in 7 (32%) of 22 patients with VS at 6 months (7 of 15 adults and 0 of 7 children; P = .05). Common mild to moderate adverse events included hypertension, fatigue, headache, and irregular menstruation. Improvement in NF2-related QOL and reduction in tinnitus-related distress were reported in 30% and 60% of participants, respectively. Paradoxically, high-dose bevacizumab treatment was not associated with a significant decrease in free vascular endothelial growth factor but was associated with increased carbonic anhydrase IX, hepatocyte growth factor, placental growth factor, stromal cell-derived factor 1α, and basic fibroblast growth factor concentrations in plasma.

CONCLUSION

High-dose bevacizumab seems to be no more effective than standard-dose bevacizumab for treatment of patients with NF2 with hearing loss. In contrast to adults, pediatric participants did not experience tumor shrinkage. However, adult and pediatric participants reported similar improvement in QOL during induction. Novel approaches using bevacizumab should be considered for children with NF2.

Meningioangiomatosis: A review of the variable manifestations and complex pathophysiology

Meningioangiomatosis (MA) is a rare, complex and heterogeneous disease of meningovascular proliferation that is found primarily in the leptomeninges and cerebral cortex but can involve subcortical white matter and other brain regions such as the cerebellum and deep gray matter. MA may be found in pediatric or adult populations and may be sporadic or neurofibromatosis-associated. The presentation of MA is highly variable: it may be associated with other neurological diseases; clinically presents on a spectrum from asymptomatic to seizures or focal deficits; radiologically presents with multifocal, tumor-like, or cystic lesions, or may appear normal; and pathologically may have cellular or vascular predominance. In this article, we review the various manifestations of MA including neurofibromatosis-associated MA, multifocal MA, cystic MA, and MA associated with meningioma, other brain tumors, focal cortical dysplasia, neurodegenerative changes, and post-radiation changes. The treatment of MA is also reviewed. While the pathogenesis of MA remains elusive, we discuss the proposed theories such as developmental, dysplastic, hamartomatous or reactive ethology in given variants. It is important for physicians to be aware of MA as more research on this complex entity is needed and timely diagnosis may benefit outcomes in patients with MA.

Giant intercostal nerve schwannoma in a patient with neurofibromatosis type 2

PURPOSE

To describe a case of giant intercostal nerve schwannoma successfully resected in a patient with neurofibromatosis type 2.

METHODS

A 44-year-old woman, with a history of neurofibromatosis type 2, presented with chest discomfort and mild dyspnea. She had undergone a recent resection of a large frontal parasagittal benign meningioma. Radiologic examinations showed a large lesion (9×12×9 cm) of the left hemithorax causing a complete atelectasis of left upper lobe. Bronchoscopy did not show any endobronchial alterations, apart from an ab estriseco compression of the left upper bronchial tree. A transthoracic needle biopsy was then performed and microscopic examination revealed a mesenchymal tumor composed of spindle-like cells.

RESULTS

A video-assisted thoracoscopic surgery procedure was proposed. The tumor mass appeared to be tenaciously adherent to the parietal pleura in its anterolateral aspect, confirming the radiologic appearance. No invasion of the lung parenchyma or parietal pleural metastases were visible. Therefore, a left posterolateral thoracotomy at the fifth intercostal space was performed and a macroscopic complete resection was carried out. The recovery was uneventful and the patient was discharged on postoperative day 5. The histologic examination revealed a moderate cellular proliferation of spindle-shaped and oval to polygonal cells with frequent Verocay bodies; mitotic figures were rare. The tumor cells were strongly S-100 positive. The microscopic features were consistent with benign intercostal schwannoma. Eight years later, the patient is disease-free and asymptomatic.

CONCLUSIONS

An unusual case of giant intercostal nerve schwannoma successfully resected in a patient with neurofibromatosis type 2 is described.

Variables affecting evaluation and publication of oncology case reports: a systematic analysis

BACKGROUND

Studies on factors affecting editorial decisions of scientific journals are scarce. In this study, we focused on case reports submitted to oncology journals and analyzed whether their nature or other relevant variables affected the chances of their acceptance.

METHODS

We analyzed case reports submitted to 2 oncology journals: Tumori Journal and The International Journal of Biological Markers, and split them into 3 predefined groups: those (a) describing rare or unusual presentation of diseases, (b) describing the side effects of an intervention or (c) describing the success of a novel intervention. Publication status was retrospectively retrieved from the submission system, and acceptance rates were calculated taking into account other variables including geographic location of corresponding author.

RESULTS

A total of 326 case reports were suitable for analysis. The acceptance rate was 35.4% for group (a), 27.9% for group (b), 19.6% for group (c) (p = 0.01). After correcting for other variables, the odds ratio (OR) of being accepted for group (c) was 0.58 (95% CI, 0.33-1.00) compared with the other groups combined. There was a highly significant difference of acceptance rates between manuscripts with authors coming from developed vs. developing countries that remained significant (OR = 5.94; 95% CI, 3.05-10.09) after correcting for multiple variables.

CONCLUSIONS

The nature of a case report in oncology may affect acceptance rate, with case reports describing successful approaches or side effects of treatment being accepted with a higher frequency then case reports describing a rare clinical or diagnostic scenario. Also, works coming from developed countries are accepted significantly more frequently than case reports coming from developing countries.