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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., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: AMG and LJK have served as unpaid advisors for AstraZeneca/Alexion; AMG has been an unpaid advisor for SpringWorks Therapeutics. DAS has been a paid consultant for Alexion. HS is CEO of Infixion Bioscience, Inc., a pharmaceutical R&D company targeting NF1.

Purpose: Neurofibromatosis type 2 (NF2) and schwannomatosis (SWN) are genetically distinct tumor predisposition syndromes with overlapping phenotypes. We sought to update the diagnostic criteria for NF2 and SWN by incorporating recent advances in genetics, ophthalmology, neuropathology, and neuroimaging., Methods: We used a multistep process, beginning with a Delphi method involving global disease experts and subsequently involving non-neurofibromatosis clinical experts, patients, and foundations/patient advocacy groups., Results: We reached consensus on the minimal clinical and genetic criteria for diagnosing NF2 and SWN. These criteria incorporate mosaic forms of these conditions. In addition, we recommend updated nomenclature for these disorders to emphasize their phenotypic overlap and to minimize misdiagnosis with neurofibromatosis type 1., Conclusion: The updated criteria for NF2 and SWN incorporate clinical features and genetic testing, with a focus on using molecular data to differentiate the 2 conditions. It is likely that continued refinement of these new criteria will be necessary as investigators study the diagnostic properties of the revised criteria and identify new genes associated with SWN. In the revised nomenclature, the term "neurofibromatosis 2" has been retired to improve diagnostic specificity., Competing Interests: Conflict of Interest R.A.A., C.O.H., and K.A.R declare no conflicts of interest. D.B.-V. is a scientific advisor for AstraZeneca, L.P. and receives grant support from the Department of Defense and SpringWorks Therapeutics. J.B. is a member of the Children’s Tumor Foundation Medical Advisory Committee and the Clinical Care Advisory Board. D.G.E. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board-Europe and has received consultancy fees from AstraZeneca, SpringWorks Therapeutics, and Recursion. R.F. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board-Europe and is a medical advisor for AstraZeneca. M.J.F. is a member of the Children’s Tumor Foundation Medical Advisory Committee. J.M.F. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board. M.G. receives grant support from NF2 Therapeutics, Inc and is a consultant for Puma Biotechnology. D.H.G. declares no conflicts of interest. M.K. is a paid consultant for Regeneron Pharmaceuticals. S.M.H. declares no conflicts of interest. H.K.-S. declares no conflicts of interest. B.R.K is a member of the Children’s Tumor Foundation Medical Advisory Committee (Chair) and is on the medical advisory boards of Genome Medicine and iNfixion Bioscience. E.L. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board-Europe. V.-F.M. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board-Europe. M.M. declares no conflicts of interest. L.P. declares no conflicts of interest. L.M. directed the Medical Genomics Laboratory at University of Alabama, Birmingham, which specializes in genetic testing for all forms of the neurofibromatosis, until April 2021. P.P. is employed by the Children’s Tumor Foundation. S.R.P is a member of the Children’s Tumor Foundation Clinical Care Advisory Board (Chair, United States) and Europe; is cofounder of NFlection Therapeutics, Inc and NF2 Therapeutics, Inc; and is a consultant for Akouos, AstraZeneca, and SonALASense. V.R. declares no conflicts of interest. E.S. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board and receives Department of Defense funding as a site for NF Clinical Trials Consortium. M.J.S declares no conflicts of interest. A.S.-R. declares no conflicts of interest. D.A.S. is a consultant for Alexion Pharmaceuticals, Inc. N.J.U is a member of the Children’s Tumor Foundation Clinical Care Advisory Board, serves on the board of Neurofibromatosis Northeast, and received a consultant fee from Astra Zeneca. D.V. is a member of the Children’s Tumor Foundation Medical Advisory Committee and Clinical Care Advisory Board, is a member of the AstraZeneca speaker’s bureau, and is on the Sanofi-Genzyme—MPS Board of Advisors. K.W. declares no conflicts of interest. P.W. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board-Europe (Chair). K.Y. is a member of the Children’s Tumor Foundation Clinical Care Advisory Board, received a consultant fee from AstraZeneca, is on the Scientific Advisory Board for iNFixion Bioscience, is member of the Programmatic Review Committee for the Department of Defense, Congressionally Directed Medical Research Program, and Neurofibromatosis Research Program., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To assess imaging utilization practices across clinical specialists in neurofibromatosis type 1 (NF1) for the evaluation of symptomatic and asymptomatic children and adults with or without plexiform neurofibromas (PN)., Methods: An institutional review board-exempt survey was administered to medical practitioners caring for individuals with NF1 at the Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) meeting in September 2019. The survey included questions on respondent demographic data (9 questions), type of imaging obtained for asymptomatic (4 questions) and symptomatic (4 questions) people with and without PN, and utilization of diffusion-weighted imaging (2 questions)., Results: Thirty practitioners participated in the survey. Most were academic neuro-oncologists at high-volume (>10 patients/week) NF1 centers. Of 30 respondents, 26 had access to whole-body MRI (WB-MRI). The most common approach to an asymptomatic person without PN was no imaging (adults: 57% [17/30]; children: 50% [15/30]), followed by a screening WB-MRI (adults: 20% [6/30]; children: 26.7% [8/30]). The most common approach to a person with symptoms or known PN was regional MRI (adults: 90% [27/30]; children: 93% [28/30]), followed by WB-MRI (adults: 20% [6/30]; children: 36.7% [11/30]). WB-MRI was most often obtained to evaluate a symptomatic child with PN (37% [11/30])., Conclusions: More than 90% of practitioners indicated they would obtain a regional MRI in a symptomatic patient without known or visible PN. Otherwise, there was little consensus on imaging practices. Given the high prevalence of PN and risk of malignant conversion in this patient population, there is a need to define imaging-based guidelines for optimal clinical care and the design of future clinical trials., (© 2021 American Academy of Neurology.)

Neurofibromatosis type 1 and type 2, affecting both children and adults, often results in devastating complications. The rapid unravelling of the genetic underpinnings of these unique disorders has led to the development of novel therapies, especially molecular-targeted therapies. To facilitate clinical trial development, the Neurofibromatosis Clinical Trial Consortium (NFCTC) was established in 2006 by the Department of Defense. Over the past decade, the Consortium has successfully completed studies for children and adults with neurofibromatosis type 1 and plexiform neurofibromas, neurocognitive challenges, low-grade gliomas, and malignant peripheral nerve sheath tumors. In addition, a study for children and adults with neurofibromatosis type 2 and acoustic schwannomas is near completion. The NFCTC has now been expanded to 19 sites in the United Stated and Australia. Mechanisms have been put in place to work closely with other consortia, foundations, and industry to expeditiously translate preclinical discoveries into clinical trials.

Objective: Neurofibromatosis (NF)-related benign tumors such as plexiform neurofibromas (PN) and vestibular schwannomas (VS) can cause substantial morbidity. Clinical trials directed at these tumors have become available. Due to differences in disease manifestations and the natural history of NF-related tumors, response criteria used for solid cancers (1-dimensional/RECIST [Response Evaluation Criteria in Solid Tumors] and bidimensional/World Health Organization) have limited applicability. No standardized response criteria for benign NF tumors exist. The goal of the Tumor Measurement Working Group of the REiNS (Response Evaluation in Neurofibromatosis and Schwannomatosis) committee is to propose consensus guidelines for the evaluation of imaging response in clinical trials for NF tumors., Methods: Currently used imaging endpoints, designs of NF clinical trials, and knowledge of the natural history of NF-related tumors, in particular PN and VS, were reviewed. Consensus recommendations for response evaluation for future studies were developed based on this review and the expertise of group members., Results: MRI with volumetric analysis is recommended to sensitively and reproducibly evaluate changes in tumor size in clinical trials. Volumetric analysis requires adherence to specific imaging recommendations. A 20% volume change was chosen to indicate a decrease or increase in tumor size. Use of these criteria in future trials will enable meaningful comparison of results across studies., Conclusions: The proposed imaging response evaluation guidelines, along with validated clinical outcome measures, will maximize the ability to identify potentially active agents for patients with NF and benign tumors.

The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration was established with the goal to develop consensus recommendations for the use of endpoints in neurofibromatosis (NF) clinical trials. This supplement includes the first series of REiNS recommendations for the use of patient-reported, functional, and visual outcomes, and for the evaluation of imaging response in NF clinical trials. Recommendations for neurocognitive outcome measures, the use of whole-body MRI in NF, the evaluation of potential biomarkers of disease, and the comprehensive evaluation of functional and patient-reported outcomes in NF are in development. The REiNS recommendations are made based on current knowledge. Experience with the use of the recommended endpoints in clinical trials, development of new tools and technologies, new knowledge of the natural history of NF, and advances in the methods used to analyze endpoints will likely lead to modifications of the currently proposed guidelines, which will be shared with the NF research community through the REiNS Web site www.reinscollaboration.org. Due to the clinical complexity of NF, there is a need to seek expertise from multiple medical disciplines, regulatory agencies, and industry to develop trial endpoints and designs, which will lead to the identification and approval of effective treatments for NF tumor and nontumor manifestations. The REiNS Collaboration welcomes anyone interested in providing his or her expertise toward this effort.

The neurofibromatoses (NF)--including neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2), and schwannomatosis--are related tumor-suppressor syndromes characterized by a predisposition to multiple tumor types and other disease manifestations, which often result in functional disability, reduced quality of life, pain, and, in some cases, malignancy. With increasing knowledge of the biology and pathogenesis of NF, clinical trials with targeted agents directed at NF tumors have become available. Most clinical trials for patients with NF have used designs and endpoints similar to oncology trials. However, differences in the disease manifestations and natural history of NF (compared to cancers) require the development of new designs and endpoints to perform meaningful NF clinical trials. The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration was established in 2011 at the Children's Tumor Foundation meeting to achieve consensus within the NF community about the design of future clinical trials, with a specific emphasis on endpoints. The REiNS Collaboration includes 7 working groups that focus on imaging of tumor response; functional, visual, patient-reported, and neurocognitive outcomes; whole-body MRI; and disease biomarkers. This supplement includes the first series of recommendations by the REiNS Collaboration. The hope is that these recommendations will be used by members of the group and by researchers outside of the REiNS International Collaboration to standardize the measurement of outcomes and thus improve clinical trials for patients with NF. Ultimately, we plan to engage industry partners and national regulatory agencies in this process to facilitate the approval of drugs for patients with NF.