Histologic correlates of "Choroidal abnormalities" in Neurofibromatosis type 1 (NF1).

Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as "choroidal abnormalities", choroidal "hyperpigmented spots" and "retinal vascular abnormalities" have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.

Preclinical evaluation of the third-generation, bi-steric mechanistic target of rapamycin complex 1-selective inhibitor RMC-6272 in NF2-deficient models.

Background: NF2-associated meningiomas are progressive, highly morbid, and nonresponsive to chemotherapies, highlighting the need for improved treatments. We have established aberrant activation of the mechanistic target of rapamycin (mTOR) signaling in NF2-deficient tumors, leading to clinical trials with first- and second-generation mTOR inhibitors. However, results have been mixed, showing stabilized tumor growth without shrinkage offset by adverse side effects. To address these limitations, here we explored the potential of third-generation, bi-steric mTOR complex 1 (mTORC1) inhibitors using the preclinical tool compound RMC-6272. Methods: Employing human NF2-deficient meningioma lines, we compared mTOR inhibitors rapamycin (first-generation), INK128 (second-generation), and RMC-6272 (third-generation) using in vitro dose-response testing, cell-cycle analysis, and immunoblotting. Furthermore, the efficacy of RMC-6272 was assessed in NF2-null 3D-spheroid meningioma models, and its in vivo potential was evaluated in 2 orthotopic meningioma mouse models. Results: Treatment of meningioma cells revealed that, unlike rapamycin, RMC-6272 demonstrated superior growth inhibitory effects, cell-cycle arrest, and complete inhibition of phosphorylated 4E-BP1 (mTORC1 readout). Moreover, RMC-6272 had a longer retention time than INK128 and inhibited the expression of several eIF4E-sensitive targets on the protein level. RMC-6272 treatment of NF2 spheroids showed significant shrinkage in size as well as reduced proliferation. Furthermore, in vivo studies in mice revealed effective blockage of meningioma growth by RMC-6272, compared with vehicle controls. Conclusions: Our study in preclinical models of NF2 supports possible future clinical evaluation of third-generation, investigational mTORC1 inhibitors, such as RMC-5552, as a potential treatment strategy for NF2.

Perspectives of adolescents with neurofibromatosis 1 and cutaneous neurofibromas: Implications for clinical trials.

BACKGROUND/AIMS: More than 99% of individuals with neurofibromatosis 1 develop cutaneous neurofibromas, benign nerve sheath tumors that manifest as nodules on the skin. These cutaneous neurofibromas emerge with age, appearing most commonly in adolescence. Nevertheless, few data have been published on how adolescents with neurofibromatosis 1 feel about cutaneous neurofibromas. The purpose of this study was to assess the perspectives of adolescents with neurofibromatosis 1 and their caregivers regarding cutaneous neurofibroma morbidity, treatment options, and acceptable risks-benefits of treatment. METHODS: An online survey was distributed through the world's largest NF registry. Eligibility criteria included self-reported neurofibromatosis 1 diagnosis, adolescent child ages 12-17 years, ≥1 cutaneous neurofibroma, and ability to read English. The survey was designed to collect details about the adolescent's cutaneous neurofibromas, views on morbidity related to cutaneous neurofibromas, social and emotional impact of cutaneous neurofibromas, communication regarding cutaneous neurofibromas, and views regarding current and potential future cutaneous neurofibroma treatment. RESULTS: Survey respondents included 28 adolescents and 32 caregivers. Adolescents reported having several negative feelings about cutaneous neurofibromas, particularly feeling worried about the potential progression of their cutaneous neurofibromas (50%). Pruritus (34%), location (34%), appearance (31%), and number (31%) were the most bothersome cutaneous neurofibroma features. Topical medication (77%-96%), followed by oral medication (54%-93%), was the most preferred treatment modality. Adolescents and caregivers most often replied that cutaneous neurofibroma treatment should be initiated when cutaneous neurofibromas become bothersome. The majority of respondents were willing to treat cutaneous neurofibromas for at least 1 year (64%-75%). Adolescent and caregivers were least willing to risk pain (72%-78%) and nausea/vomiting (59%-81%) as a cutaneous neurofibroma treatment side effect. CONCLUSIONS: These data indicate that adolescents with neurofibromatosis 1 are negatively impacted by their cutaneous neurofibromas, and that both adolescents and their caregivers would be willing to try longer-term experimental treatments.

Potential endpoints for assessment of bone health in persons with neurofibromatosis type 1.

Neurofibromatosis type 1 is a genetic syndrome characterized by a wide variety of tumor and non-tumor manifestations. Bone-related issues, such as scoliosis, tibial dysplasia, and low bone mineral density, are a significant source of morbidity for this population with limited treatment options. Some of the challenges to developing such treatments include the lack of consensus regarding the optimal methods to assess bone health in neurofibromatosis type 1 and limited data regarding the natural history of these manifestations. In this review, the Functional Committee of the Response Evaluation in Neurofibromatosis and Schwannomatosis International Collaboration: (1) presents the available techniques for measuring overall bone health and metabolism in persons with neurofibromatosis type 1, (2) reviews data for use of each of these measures in the neurofibromatosis type 1 population, and (3) describes the strengths and limitations for each method as they might be used in clinical trials targeting neurofibromatosis type 1 bone manifestations. The Response Evaluation in Neurofibromatosis and Schwannomatosis International Collaboration supports the development of a prospective, longitudinal natural history study focusing on the bone-related manifestations and relevant biomarkers of neurofibromatosis type 1. In addition, we suggest that the neurofibromatosis type 1 research community consider adding the less burdensome measurements of bone health as exploratory endpoints in ongoing or planned clinical trials for other neurofibromatosis type 1 manifestations to expand knowledge in the field.

A core outcome domain set to assess cutaneous neurofibromas related to neurofibromatosis type 1 in clinical trials.

BACKGROUND: Cutaneous neurofibromas (cNF) are considered one of the highest burdens of neurofibromatosis type 1 (NF1). To date, no medical treatment can cure cNF or prevent their development. In that context, there is an urgent need to prepare and standardize the methodology of future trials targeting cNF. OBJECTIVES: The objective was to develop a core outcome domain set suitable for all clinical trials targeting NF1-associated cNF. METHODS: The validated approach of this work consisted of a three-phase methodology: (i) generating the domains [systematic literature review (SLR) and qualitative studies]; (ii) agreeing (three-round international e-Delphi consensus process and working groups); and (iii) voting. RESULTS: (i) The SLR and the qualitative studies (three types of focus groups and a French e-survey with 234 participants) resulted in a preliminary list of 31 candidate items and their corresponding definitions. (ii) A total of 229 individuals from 29 countries participated in the first round of the e-Delphi process: 71 patients, relatives or representatives (31.0%), 130 healthcare professionals (HCPs, 56.8%) and 28 researchers, representatives of a drug regulatory authority, industry or pharmaceutical company representatives or journal editors (12.2%). The overall participation rate was 74%. After round 2, five candidate items were excluded. Between rounds 2 and 3, international workshops were held to better understand the disagreements among stakeholders. This phase led to the identification of 19 items as outcome subdomains. (iii) The items were fused to create four outcome domains ('clinical assessment', 'daily life impact', 'patient satisfaction' and 'perception of health') and prioritized. The seven items that did not reach consensus were marked for the research agenda. The final core outcome domain set reached 100% of the votes of the steering committee members. CONCLUSIONS: Although numerous outcomes can be explored in studies related to cNF in NF1, the present study offers four outcome domains that should be reported in all trial studies, agreed on by international patients, relatives and representatives of patients; HCPs; researchers, representatives of drug regulatory authorities or pharmaceutical companies and journal editors. The next step will include the development of a set of core outcome measurement instruments to further standardize how these outcomes should be assessed.

Gene-targeted therapy for neurofibromatosis and schwannomatosis: The path to clinical trials.

Numerous successful gene-targeted therapies are arising for the treatment of a variety of rare diseases. At the same time, current treatment options for neurofibromatosis 1 and schwannomatosis are limited and do not directly address loss of gene/protein function. In addition, treatments have mostly focused on symptomatic tumors, but have failed to address multisystem involvement in these conditions. Gene-targeted therapies hold promise to address these limitations. However, despite intense interest over decades, multiple preclinical and clinical issues need to be resolved before they become a reality. The optimal approaches to gene-, mRNA-, or protein restoration and to delivery to the appropriate cell types remain elusive. Preclinical models that recapitulate manifestations of neurofibromatosis 1 and schwannomatosis need to be refined. The development of validated assays for measuring neurofibromin and merlin activity in animal and human tissues will be critical for early-stage trials, as will the selection of appropriate patients, based on their individual genotypes and risk/benefit balance. Once the safety of gene-targeted therapy for symptomatic tumors has been established, the possibility of addressing a wide range of symptoms, including non-tumor manifestations, should be explored. As preclinical efforts are underway, it will be essential to educate both clinicians and those affected by neurofibromatosis 1/schwannomatosis about the risks and benefits of gene-targeted therapy for these conditions.

Development of a MEK inhibitor, NFX-179, as a chemoprevention agent for squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer. Although cSCC contributes to substantial morbidity and mortality in high-risk individuals, deployment of otherwise effective chemoprevention of cSCC is limited by toxicities. Our systematic computational drug repurposing screen predicted that selumetinib, a MAPK (mitogen-activated protein kinase) kinase inhibitor (MEKi), would reverse transcriptional signatures associated with cSCC development, consistent with our genomic analysis implicating MEK as a chemoprevention target. Although systemic MEKi suppresses the formation of cSCC in mice, systemic MEKi can cause severe adverse effects. Here, we report the development of a metabolically labile MEKi, NFX-179, designed to potently and selectively suppress the MAPK pathway in the skin before rapid metabolism in the systemic circulation. NFX-179 was identified on the basis of its biochemical and cellular potency, selectivity, and rapid metabolism upon systemic absorption. In our ultraviolet-induced cSCC mouse model, topical application of NFX-179 gel reduced the formation of new cSCCs by an average of 60% at doses of 0.1% and greater at 28 days. We further confirmed the localized nature of these effects in an additional split-mouse randomized controlled study where suppression of cSCC was observed only in drug-treated areas. No toxicities were observed. NFX-179 inhibits the growth of human SCC cell lines in a dose-dependent manner, and topical NFX-179 application penetrates human skin and inhibits MAPK signaling in human cSCC explants. Together, our data provide a compelling rationale for using topical MEK inhibition through the application of NFX-179 gel as an effective strategy for cSCC chemoprevention.

Association of MTHFR Polymorphisms With Leukoencephalopathy Risk in Patients With Primary CNS Lymphoma Treated With Methotrexate-Based Regimens.

OBJECTIVES: The folate antagonist high-dose methotrexate (HD-MTX) is integral to induction chemotherapy for primary CNS lymphoma (PCNSL); however, it can be associated with leukoencephalopathy. Methylenetetrahydrofolate reductase (MTHFR) is involved in intracellular folate depletion. We assessed whether MTHFR polymorphisms affect the risk of leukoencephalopathy. METHODS: We retrospectively searched our database at the Massachusetts General Hospital for newly diagnosed PCNSL treated with HD-MTX (without radiotherapy nor intrathecal chemotherapy). RESULTS: Among 68 patients with PCNSL, MTHFR polymorphisms were found in 60 individuals (88.2%) including a 677C→T genotype, a 1298A→C genotype, or a combined 677C→T/1298A→C genotype. Neither MTX clearance nor response to induction therapy was affected by specific genotypes, and complete response was achieved in 72.1% of patients by HD-MTX-based induction. However, the 1298A→C genotype was associated with increased frequency and severity of leukoencephalopathy over time (odds ratio 4.0, CI 1.5-11.4). Such genotype predicted treatment-induced leukoencephalopathy with a sensitivity of 71.0% and a specificity of 62.2% (area under the curve 0.67, CI 0.5-0.8; p = 0.019). While progression-free survival did not differ in genotype-based subgroups, overall survival was lower for the 1298A→C genotype. DISCUSSION: The MTHFR 1298A→C genotype may serve to identify patients with PCNSL at elevated risk of HD-MTX-induced leukoencephalopathy. This seems to translate into reduced survival, potentially due to decreased functional status.

Neurotoxicity and management of primary and secondary central nervous system lymphoma after adoptive immunotherapy with CD19-directed chimeric antigen receptor T-cells.

BACKGROUND: Chimeric antigen receptor (CAR) T-cells targeting CD19 have been established as a leading engineered T-cell therapy for B-cell lymphomas; however, data for patients with central nervous system (CNS) involvement are limited. METHODS: We retrospectively report on CNS-specific toxicities, management, and CNS response of 45 consecutive CAR T-cell transfusions for patients with active CNS lymphoma at the Massachusetts General Hospital over a 5-year period. RESULTS: Our cohort includes 17 patients with primary CNS lymphoma (PCNSL; 1 patient with 2 CAR T-cell transfusions) and 27 patients with secondary CNS lymphoma (SCNSL). Mild ICANS (grade 1-2) was observed after 19/45 transfusions (42.2%) and severe immune effector cell-associated neurotoxicity syndrome (ICANS) (grade 3-4) after 7/45 transfusions (15.6%). A larger increase in C-reactive protein (CRP) levels and higher rates of ICANS were detected in SCNSL. Early fever and baseline C-reactive protein levels were associated with ICANS occurrence. CNS response was seen in 31 cases (68.9%), including a complete response of CNS disease in 18 cases (40.0%) which lasted for a median of 11.4 ±â€…4.5 months. Dexamethasone dose at time of lymphodepletion (but not at or after CAR T-cell transfusion) was associated with an increased risk for CNS progression (hazard ratios [HR] per mg/d: 1.16, P = .031). If bridging therapy was warranted, the use of ibrutinib translated into favorable CNS-progression-free survival (5 vs. 1 month, HR 0.28, CI 0.1-0.7; P = .010). CONCLUSIONS: CAR T-cells exhibit promising antitumor effects and a favorable safety profile in CNS lymphoma. Further evaluation of the role of bridging regimens and corticosteroids is warranted.

Effect of Mind-Body Skills Training on Quality of Life for Geographically Diverse Adults With Neurofibromatosis: A Fully Remote Randomized Clinical Trial.

Importance: Neurofibromatoses (NF; NF1, NF2, and schwannomatosis) are hereditary tumor predisposition syndromes with a risk for poor quality of life (QOL) and no evidence-based treatments. Objective: To compare a mind-body skills training program, the Relaxation Response Resiliency Program for NF (3RP-NF), with a health education program (Health Enhancement Program for NF; HEP-NF) for improvement of quality of life among adults with NF. Design, Setting, and Participants: This single-blind, remote randomized clinical trial randomly assigned 228 English-speaking adults with NF from around the world on a 1:1 basis, stratified by NF type, between October 1, 2017, and January 31, 2021, with the last follow-up February 28, 2022. Interventions: Eight 90-minute group virtual sessions of 3RP-NF or HEP-NF. Main Outcomes and Measures: Outcomes were collected at baseline, after treatment, and at 6-month and 1-year follow-up. The primary outcomes were physical health and psychological domain scores of the World Health Organization Quality of Life Brief Version (WHOQOL-BREF). Secondary outcomes were the social relationships and environment domain scores of the WHOQOL-BREF. Scores are reported as transformed domain scores (range, 0-100, with higher scores indicating higher QOL). Analysis was performed on an intention-to-treat basis. Results: Of 371 participants who underwent screening, 228 were randomized (mean [SD] age, 42.7 [14.5] years; 170 women [75%]), and 217 attended 6 or more of 8 sessions and provided posttest data. Participants in both programs improved from baseline to after treatment in primary outcomes of physical health QOL score (3RP-NF, 5.1; 95% CI, 3.2-7.0; P < .001; HEP-NF, 6.4; 95% CI, 4.6-8.3; P < .001) and psychological QOL score (3RP-NF, 8.5; 95% CI, 6.4-10.7; P < .001; HEP-NF, 9.2; 95% CI, 7.1-11.2; P < .001). Participants in the 3RP-NF group showed sustained improvements after treatment to 12 months; posttreatment improvements for the HEP-NF group diminished (between-group difference for physical health QOL score, 4.9; 95% CI, 2.1-7.7; P = .001; effect size [ES] = 0.3; and psychological QOL score, 3.7; 95% CI, 0.2-7.6; P = .06; ES = 0.2). Results were similar for secondary outcomes of social relationships and environmental QOL. There were significant between-group differences from baseline to 12 months in favor of the 3RP-NF for physical health QOL score (3.6; 95% CI, 0.5-6.6; P = .02; ES = 0.2), social relationships QOL score (6.9; 95% CI, 1.2-12.7; P = .02; ES = 0.3), and environmental QOL score (3.5; 95% CI, 0.4-6.5; P = .02; ES = 0.2). Conclusions and Relevance: In this randomized clinical trial of 3RP-NF vs HEP-NF, benefits from 3RP-NF and HEP-NF were comparable after treatment, but at 12 months from baseline, 3RP-NF was superior to HEP-NF on all primary and secondary outcomes. Results support the implementation of 3RP-NF in routine care. Trial Registration: ClinicalTrials.gov Identifier: NCT03406208.

Prospective phase II trial of the dual mTORC1/2 inhibitor vistusertib for progressive or symptomatic meningiomas in persons with neurofibromatosis 2.

Background: Meningiomas occur in 80% of persons with neurofibromatosis 2 (NF2) and cause significant mortality and morbidity, yet there are no effective medical treatments. NF2-deficient tumors have constitutive activation of mammalian/mechanistic target of rapamycin (mTOR), and treatment with mTORC1 inhibitors results in growth arrest in a minority of tumors, with paradoxical activation of the mTORC2/AKT pathway. We studied the effect of vistusertib, a dual mTORC1/mTORC2 inhibitor, in NF2 patients with progressive or symptomatic meningiomas. Methods: Vistusertib was administered orally at 125 mg twice daily for 2 consecutive days each week. The primary endpoint was the imaging response in the target meningioma, defined as a volume decrease of 20% compared with the baseline. Secondary endpoints included toxicity, imaging response of nontarget tumors, quality of life, and genetic biomarkers. Results: Eighteen participants (13 female), median age of 41 (range, 18-61) years, were enrolled. In target meningiomas, the best response was partial response (PR) in 1/18 tumors (6%) and stable disease (SD) in 17/18 tumors (94%). For all measured intracranial meningiomas and vestibular schwannomas, the best imaging response was PR in 6/59 tumors (10%) and SD in 53 (90%). Treatment-related grade 3/4 adverse events occurred in 14 (78%) participants, and 9 participants discontinued treatment due to side effects. Conclusions: Although the study did not meet the primary endpoint, vistusertib treatment was associated with high rates of SD in progressive NF2-related tumors. However, this dosing regimen for vistusertib was poorly tolerated. Future studies of dual mTORC inhibitors for NF2 should focus on optimizing tolerability and evaluating the relevance of tumor stability in participants.

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.

Proton Radiotherapy for Vestibular Schwannomas in Patients with NF2-Related Schwannomatosis: A Case Series.

(1) Background: This study aimed to evaluate the efficacy and treatment-related toxicity of proton radiotherapy (PRT) for vestibular schwannoma (VS) in patients with neurofibromatosis type 2-related schwannomatosis (NF2). (2) Methods: Consecutive NF2 patients treated with PRT for VS between 2004 and 2016 were retrospectively evaluated, focusing on tumor volume, facial and trigeminal nerve function, hearing, tinnitus, vestibular symptoms, and the need for salvage therapy after PRT. (3) Results: Eight patients were included (median age 36 years, 50% female). Median follow-up was 71 months. Five (63%) patients received fractionated PRT and three (38%) received PRT radiosurgery for VS. Six patients (75%) received prior VS surgery; three also received bevacizumab. Six patients (75%) did not require salvage therapy after PRT. Two patients (25%) with residual hearing lost it after PRT, and six had already lost ipsilateral hearing prior to PRT. Tumor and treatment-related morbidity could be evaluated in six patients. Following PRT, conditions that occurred or worsened were: facial paresis in five (83%), trigeminal hypoesthesia in two (33%), tinnitus in two (33%), and vestibular symptoms in four patients (67%). (4) Conclusion: After PRT for VS, the majority of the NF2 patients in the cohort did not require additional therapy. Tumor and/or treatment-related cranial nerve deficits were common. This is at least partly explained by the use of PRT as a salvage treatment after surgery or bevacizumab, in the majority of cases. There remains the further opportunity to elucidate the efficacy and toxicity of proton radiotherapy as a primary treatment.

Co-Targeting IL-6 and EGFR signaling for the treatment of schwannomatosis and associated pain.

Patients with Schwannomatosis (SWN) overwhelmingly present with intractable, debilitating chronic pain. There are no effective therapies to treat SWN. The drivers of pain response and tumor progression in SWN are not clear. The pain is not proportionally linked to tumor size and is not always relieved by tumor resection, suggesting that mechanisms other than mechanical nerve compression exist to cause pain. SWN research is limited by the lack of clinically-relevant models. Here, we established novel patient-derived xenograft (PDX) models, dorsal root ganglia (DRG) imaging model, and combined with single-cell resolution intravital imaging and RNASeq, we discovered: i) schwannomas on the peripheral nerve cause macrophage influx into the DRG, via secreting HMGB1 to directly stimulate DRG neurons to express CCL2, the key macrophage chemokine, ii) once recruited, macrophages cause pain response via overproduction of IL-6, iii) IL-6 blockade in a therapeutic setting significantly reduces pain but has modest efficacy on tumor growth, iv) EGF signaling is a potential driver of schwannoma growth and escape mechanism from anti-IL6 treatment, and v) combined IL-6 and EGFR blockade simultaneously controlled pain and tumor growth in SWN models. Our findings prompted the initiation of phase II clinical trial ( NCT05684692 ) for pain relief in patients with SWN.

Proteasomal pathway inhibition as a potential therapy for NF2-associated meningioma and schwannoma.

BACKGROUND: Neurofibromatosis 2 (NF2) is an inherited disorder caused by bi-allelic inactivation of the NF2 tumor suppressor gene. NF2-associated tumors, including schwannoma and meningioma, are resistant to chemotherapy, often recurring despite surgery and/or radiation, and have generally shown cytostatic response to signal transduction pathway inhibitors, highlighting the need for improved cytotoxic therapies. METHODS: Leveraging data from our previous high-throughput drug screening in NF2 preclinical models, we identified a class of compounds targeting the ubiquitin-proteasome pathway (UPP), and undertook studies using candidate UPP inhibitors, ixazomib/MLN9708, pevonedistat/MLN4924, and TAK-243/MLN7243. Employing human primary and immortalized meningioma (MN) cell lines, CRISPR-modified Schwann cells (SCs), and mouse Nf2-/- SCs, we performed dose response testing, flow cytometry-based Annexin V and cell cycle analyses, and RNA-sequencing to identify potential underlying mechanisms of apoptosis. In vivo efficacy was also assessed in orthotopic NF2-deficient meningioma and schwannoma tumor models. RESULTS: Testing of three UPP inhibitors demonstrated potent reduction in cell viability and induction of apoptosis for ixazomib or TAK-243, but not pevonedistat. In vitro analyses revealed that ixazomib or TAK-243 downregulates expression of c-KIT and PDGFRα, as well as the E3 ubiquitin ligase SKP2 while upregulating genes associated with endoplasmic reticulum stress-mediated activation of the unfolded protein response (UPR). In vivo treatment of mouse models revealed delayed tumor growth, suggesting a therapeutic potential. CONCLUSIONS: This study demonstrates the efficacy of proteasomal pathway inhibitors in meningioma and schwannoma preclinical models and lays the groundwork for use of these drugs as a promising novel treatment strategy for NF2 patients.

COVID-19 in people with neurofibromatosis 1, neurofibromatosis 2, or schwannomatosis.

PURPOSE: People with pre-existing conditions may be more susceptible to severe COVID-19 when infected by SARS-CoV-2. The relative risk and severity of SARS-CoV-2 infection in people with rare diseases such as neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), or schwannomatosis (SWN) is unknown. METHODS: We investigated the proportions of people with NF1, NF2, or SWN in the National COVID Cohort Collaborative (N3C) electronic health record data set who had a positive test result for SARS-CoV-2 or COVID-19. RESULTS: The cohort sizes in N3C were 2501 (NF1), 665 (NF2), and 762 (SWN). We compared these with N3C cohorts of patients with other rare diseases (98-9844 individuals) and the general non-NF population of 5.6 million. The site- and age-adjusted proportion of people with NF1, NF2, or SWN who had a positive test result for SARS-CoV-2 or COVID-19 (collectively termed positive cases) was not significantly higher than in individuals without NF or other selected rare diseases. There were no severe outcomes reported in the NF2 or SWN cohorts. The proportion of patients experiencing severe outcomes was no greater for people with NF1 than in cohorts with other rare diseases or the general population. CONCLUSION: Having NF1, NF2, or SWN does not appear to increase the risk of being SARS-CoV-2 positive or of being a patient with COVID-19 or of developing severe complications from SARS-CoV-2.

Ten-Year Follow-up of Internal Neurofibroma Growth Behavior in Adult Patients With Neurofibromatosis Type 1 Using Whole-Body MRI.

BACKGROUND AND OBJECTIVES: Internal neurofibromas, including plexiform neurofibromas (PNF), can cause significant morbidity in patients with neurofibromatosis type 1 (NF1). PNF growth is most pronounced in children and young adults, with more rapid growth thought to occur in a subset of PNF termed distinct nodular lesions (DNL). Growth behavior of internal neurofibromas and DNL in older adults is not well documented; yet knowledge thereof is important for patient risk stratification and clinical trial design. The primary objective of this study was to evaluate the long-term growth behavior of internal neurofibromas in adults with NF1. Secondary objectives were to correlate tumor growth behavior with patient-specific, tumor-specific, and patient-reported variables. METHODS: In this prospective cohort study, internal neurofibromas were identified on coronal short TI inversion recovery sequences on baseline and follow-up whole-body MRIs (WBMRIs). Tumor growth and shrinkage were defined as a volume change ≥20%. The association between tumor growth and patient-specific (baseline age, sex, and genotype), tumor-specific (morphology, location, DNL presence on baseline WBMRI, and maximum standardized uptake value on baseline PET imaging), and patient-reported variables (endogenous and exogenous hormone exposure, pain intensity, and quality of life) was assessed using the Spearman correlation coefficient and Kruskal-Wallis test. RESULTS: Of 106 patients with a baseline WBMRI obtained as part of a previous research study, 44 had a follow-up WBMRI. Three additional patients with WBMRIs acquired for clinical care were included, generating 47 adults for this study. The median age during baseline WBMRI was 42 years (range 18-70). The median time between WBMRIs was 10.4 years. Among 324 internal neurofibromas, 62.8% (56% of PNF and 62.1% of DNL) shrank spontaneously without treatment and 17.1% (17.9% of PNF and 13.8% of DNL) grew. Growth patterns were heterogeneous within participants. Patient-specific, tumor-specific, and patient-reported variables (including endogenous and exogenous hormone exposure) were not strong predictors of tumor growth. DISCUSSION: Internal neurofibroma growth behavior in older adults differs fundamentally from that in children and young adults, with most tumors, including DNL, demonstrating spontaneous shrinkage. Better growth models are needed to understand factors that influence tumor growth. These results will inform clinical trial design for internal neurofibromas.

Design of a randomized, placebo-controlled, phase 2 study evaluating the safety and efficacy of tanezumab for treatment of schwannomatosis-related pain.

BACKGROUND: Schwannomatosis (SWN) is a rare tumor suppressor syndrome that predisposes affected individuals to develop multiple schwannomas and, less often, meningiomas. The most common symptom is chronic, severe pain. No medications are broadly effective in treating SWN-associated pain. The clinical trial described in this manuscript is a phase 2, randomized, double-blind, placebo-controlled study investigating the safety and efficacy of tanezumab - a humanized monoclonal antibody that inhibits nerve growth factor - for treatment of SWN-related pain. As the first therapeutic trial for SWN-related pain, it also aims to evaluate trial endpoints, understand recruitment patterns, and improve clinical trial design in this rare disease. AIMS: The primary objective of this trial is to assess the analgesic efficacy of subcutaneous tanezumab 10 mg in subjects with SWN who continue pre-existing pain therapy (excluding non-steroidal anti-inflammatory drugs). The secondary objective is to assess safety in this population. Exploratory objectives include assessment of pain features, quality of life, and predictive biomarkers. METHODS: The study is comprised of four periods (pre-treatment, double-blind treatment, single-arm treatment, safety follow-up) across 10 months with a delayed-start trial design to allow all participants to receive tanezumab. Forty-six participants will be enrolled and randomized 1:1 to receive either tanezumab or placebo subcutaneously in the double-blind treatment period; all participants receive tanezumab during the single-arm treatment period. CONCLUSIONS: This study is the first therapeutic trial for SWN patients and targets a biological driver of SWN-related pain. It aims to establish a model for future pain studies in SWN and other rare diseases. CLINICAL TRIAL REGISTRATION: NCT04163419 on ClinicalTrials.gov.

Gene replacement therapy in a schwannoma mouse model of neurofibromatosis type 2.

Loss of function of the neurofibromatosis type 2 (NF2) tumor suppressor gene leads to the formation of schwannomas, meningiomas, and ependymomas, comprising ∼50% of all sporadic cases of primary nervous system tumors. NF2 syndrome is an autosomal dominant condition, with bi-allelic inactivation of germline and somatic alleles resulting in loss of function of the encoded protein merlin and activation of mammalian target of rapamycin (mTOR) pathway signaling in NF2-deficient cells. Here we describe a gene replacement approach through direct intratumoral injection of an adeno-associated virus vector expressing merlin in a novel human schwannoma model in nude mice. In culture, the introduction of an AAV1 vector encoding merlin into CRISPR-modified human NF2-null arachnoidal cells (ACs) or Schwann cells (SCs) was associated with decreased size and mTORC1 pathway activation consistent with restored merlin activity. In vivo, a single injection of AAV1-merlin directly into human NF2-null SC-derived tumors growing in the sciatic nerve of nude mice led to regression of tumors over a 10-week period, associated with a decrease in dividing cells and an increase in apoptosis, in comparison with vehicle. These studies establish that merlin re-expression via gene replacement in NF2-null schwannomas is sufficient to cause tumor regression, thereby potentially providing an effective treatment for NF2.