Identifying Lesions of the Corpus Callosum in Patients With Neurofibromatosis Type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is a multisystemic autosomal dominant disorder that includes intracranial lesions such as unidentified bright objects (UBOs)-areas of increased T2 signal on magnetic resonance imaging (MRI)-and tumors known as gliomas. The presence of these lesions in the corpus callosum (CC) has not been previously studied in a large cohort.

METHODS

We reviewed medical records of 681 patients (aged three months to 86 years) followed at our institution from 2000 to 2023 with NF1 and one or more brain MRI. Patients with lesions in the CC were identified, and RAPNO/RANO criteria were used to determine changes in size over time, where a change of 25% in the product of perpendicular measurements indicates growth or shrinkage.

RESULTS

Forty-seven patients had CC UBOs, most of which were in the splenium (66.0%). Seventeen patients had CC gliomas (10% of those with any glioma), two of whom had two gliomas. Seventeen of 19 gliomas were in the splenium. Over follow-up, eight of 19 remained stable, three shrunk, and eight grew. The mean percentage change in the product of the dimensions was 311.5% (ranging from -46.7% to 2566.6%). Of the eight lesions that grew, one required treatment.

CONCLUSIONS

There is a 6.9% and 2.5% prevalence of CC UBOs and gliomas, respectively, in our cohort of patients with NF1. Most lesions are present in the splenium, and although some gliomas demonstrate significant growth, they rarely require treatment. This work is the largest series of CC lesions in NF1 and adds to the growing data to inform appropriate follow-up.

Endoglin, a Novel Biomarker and Therapeutical Target to Prevent Malignant Peripheral Nerve Sheath Tumor Growth and Metastasis

PURPOSE

Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive soft-tissue sarcomas that lack effective treatments, underscoring the urgent need to uncover novel mediators of MPNST pathogenesis that may serve as potential therapeutic targets. Tumor angiogenesis is considered a critical event in MPNST transformation and progression. Here, we have investigated whether endoglin (ENG), a TGFβ coreceptor with a crucial role in angiogenesis, could be a novel therapeutic target in MPNSTs.

EXPERIMENTAL DESIGN

ENG expression was evaluated in human peripheral nerve sheath tumor tissues and plasma samples. Effects of tumor cell-specific ENG expression on gene expression, signaling pathway activation and in vivo MPNST growth and metastasis, were investigated. The efficacy of ENG targeting in monotherapy or in combination with MEK inhibition was analyzed in xenograft models.

RESULTS

ENG expression was found to be upregulated in both human MPNST tumor tissues and plasma-circulating small extracellular vesicles. We demonstrated that ENG modulates Smad1/5 and MAPK/ERK pathway activation and pro-angiogenic and pro-metastatic gene expression in MPNST cells and plays an active role in tumor growth and metastasis in vivo. Targeting with ENG-neutralizing antibodies (TRC105/M1043) decreased MPNST growth and metastasis in xenograft models by reducing tumor cell proliferation and angiogenesis. Moreover, combination of anti-ENG therapy with MEK inhibition effectively reduced tumor cell growth and angiogenesis.

CONCLUSIONS

Our data unveil a tumor-promoting function of ENG in MPNSTs and support the use of this protein as a novel biomarker and a promising therapeutic target for this disease.

CTNI-65. INTUITT-NF2, AN ADAPTIVE PLATFORM-BASKET TRIAL FOR NEUROFIBROMATOSIS 2 PATIENTS WITH PROGRESSIVE TUMORS: INTERIM RESULTS OF THE BRIGATINIB TREATMENT ARM

Neurofibromatosis type 2 (NF2) predisposes affected individuals to vestibular schwannomas (VS), non-vestibular schwannomas (NVS), meningiomas, and ependymomas. We developed an adaptive platform-basket trial to screen multiple drugs against any type of progressive NF2-related tumor. We report the interim analysis of the first treatment arm with brigatinib, an ALK inhibitor that inhibits multiple tyrosine kinases. We conducted a multicenter, phase II, open-label study for subjects ≥12 years old with NF2 and progressive target tumors (baskets: VS, NVS, meningioma, or ependymoma). Up to 5 non-target tumors were followed in each participant. In stage 1, 20 participants (minimum of 2 participants per basket) were treated with brigatinib 180 mg daily. Tumor response was evaluated by MRI every 3 months in year 1 and every 6 months thereafter. Radiographic response (RR) was defined as ≥20% decrease in target tumor volume from baseline. The primary outcome was RR rate. Per protocol, the brigatinib arm would be discontinued if no target tumor achieved a RR at interim analysis. Twenty subjects (median age=25 years, 7 pediatric, 12 females) were treated. Target tumors included 10 VS, 3 NVS, 5 meningiomas, and 2 ependymomas; non-target tumors included 18 VS, 36 NVS, and 14 meningiomas. RR rate for target and non-target tumors was 5% and 22%, respectively. By tumor basket, RR was 28% for meningioma, 26% for non-VS, 4% for VS, and 0% for ependymomas. Annualized tumor growth rates decreased for VS, NVS, and meningioma during treatment. Brigatinib was well tolerated with one dose reduction and one discontinuation due to grade 2 diarrhea. Brigatinib treatment was associated with RR in meningiomas, VS, and NVS. In stage 2, the study will enroll 20 participants in the two most promising baskets (meningioma and NVS). This novel design provides unique ability to assess treatments for hereditary syndromes with multiple primary tumors.

MEK inhibitors for neurofibromatosis type 1 manifestations: Clinical evidence and consensus

The wide variety of clinical manifestations of the genetic syndrome neurofibromatosis type 1 (NF1) are driven by overactivation of the RAS pathway. Mitogen-activated protein kinase kinase inhibitors (MEKi) block downstream targets of RAS. The recent regulatory approvals of the MEKi selumetinib for inoperable symptomatic plexiform neurofibromas in children with NF1 have made it the first medical therapy approved for this indication in the United States, the European Union, and elsewhere. Several recently published and ongoing clinical trials have demonstrated that MEKi may have potential benefits for a variety of other NF1 manifestations, and there is broad interest in the field regarding the appropriate clinical use of these agents. In this review, we present the current evidence regarding the use of existing MEKi for a variety of NF1-related manifestations, including tumor (neurofibromas, malignant peripheral nerve sheath tumors, low-grade glioma, and juvenile myelomonocytic leukemia) and non-tumor (bone, pain, and neurocognitive) manifestations. We discuss the potential utility of MEKi in related genetic conditions characterized by overactivation of the RAS pathway (RASopathies). In addition, we review practical treatment considerations for the use of MEKi as well as provide consensus recommendations regarding their clinical use from a panel of experts.

Management of neurofibromatosis type 1-associated plexiform neurofibromas

Plexiform Neurofibromas (PN) are a common manifestation of the genetic disorder neurofibromatosis type 1 (NF1). These benign nerve sheath tumors often cause significant morbidity, with treatment options limited historically to surgery. There have been tremendous advances over the past two decades in our understanding of PN, and the recent regulatory approvals of the MEK inhibitor selumetinib are reshaping the landscape for PN management. At present, there is no agreed upon PN definition, diagnostic evaluation, surveillance strategy, or clear indications for when to initiate treatment and selection of treatment modality. In this review, we address these questions via consensus recommendations from a panel of multidisciplinary NF1 experts.

CLRM-16 PATIENT-FOCUSED DRUG DEVELOPMENT IN NEURO-ONCOLOGY: A PILOT STUDY OF QUALITATIVE PATIENT INTERVIEWS EMBEDDED WITHIN A NEUROFIBROMATOSIS 2 CLINICAL TRIAL

BACKGROUND

The Food and Drug Administration recently issued guidance on conducting qualitative research to support patient-focused drug development. In prior FDA submissions, qualitative data has been critical to demonstrate the content validity of and meaningfulness of change in quantitative trial endpoints. Qualitative patient interviews embedded within neuro-oncology trials can supplement traditional quantitative measures by providing nuanced information on patients’ treatment priorities, benefit/risk assessments, and quality of life.

METHODS

We interviewed people with neurofibromatosis 2 (NF2) in stage one of the brigatinib arm of a multicenter, phase II, adaptive platform-basket trial for progressive NF2-related tumors (NCT04374305). Transcripts were coded by two analysts using a hybrid inductive/deductive framework; cross-cutting themes were generated using the Framework Method.

RESULTS

16/20 trial enrollees participated in interviews May 2021-March 2022. The radiographic response rate (volume shrinkage ≥20% from baseline) at 6 months for target and non-target tumors was 5% and 22%, respectively. However, most participants rated their change in overall status as minimally (10/16) or much (3/16) improved. Several participants acknowledged their tumor size had not changed significantly but felt tumor stability was an improvement over previously accelerated growth rates; this importantly allowed them to avoid or postpone future surgery. Participants also valued prevention of symptomatic decline, minimal impact of side effects on social roles and activities, the convenience of oral medication, and the sense of hope and agency gained from participating in a trial.

CONCLUSIONS

Virtual, in-depth qualitative interviews were feasible across multiple sites and provided unique information on NF2 patients’ conceptualization of clinical benefit. Qualitative interviews embedded within neuro-oncology trials can reveal 1) whether trial design and choice of outcome measures align with patient priorities; 2) whether and how new treatments improve patients’ quality of life; and 3) what degree of change in quantitative measures such as radiographic progression are clinically meaningful.

Management and surgical outcomes of dystrophic scoliosis in neurofibromatosis type 1: a systematic review

OBJECTIVE

Neurofibromatosis type 1 (NF1) dystrophic scoliosis is an early-onset, rapidly progressive multiplanar deformity. There are few studies on the surgical management of this patient population. Specifically, perioperative morbidity, instrument-related complications, and quality-of-life outcomes associated with surgical management have not been systematically evaluated. In this study, the authors aimed to perform a systematic review on the natural history, management options, and surgical outcomes in patients who underwent NF1 dystrophic scoliosis surgery.

METHODS

A PubMed search for articles with “neurofibromatosis” and either “dystrophic” or “scoliosis” in the title or abstract was performed. Articles with 10 or more patients undergoing surgery for NF1 dystrophic scoliosis were included. Data regarding indications, treatment details, morbidity, and outcomes were summarized and analyzed with descriptive statistics.

RESULTS

A total of 310 articles were identified, 48 of which were selected for full-text review; 30 studies describing 761 patients met the inclusion criteria. The mean age ranged from 7 to 22 years, and 99.7% of patients were younger than 18 years. The mean preoperative coronal Cobb angle was 75.2°, and the average correction achieved was 40.3°. The mean clinical follow-up in each study was at least 2 years (range 2.2–19 years). All patients underwent surgery with the intent of deformity correction. The scoliosis regions addressed were thoracic curves (69.6%) and thoracolumbar (11.1%) and lumbar (14.3%) regions. The authors reported on a variety of approaches: posterior-only, combined anterior-posterior, and growth-friendly surgery. For fixation techniques, 42.5% of patients were treated with hybrid constructs, 51.5% with pedicle screw–only constructs, and 6.0% with hook-based constructs. Only 0.9% of patients underwent a vertebral column resection. The nonneurological complication rate was 14.0%, primarily dural tears and wound infections. The immediate postoperative neurological deficit rate was 2.1%, and the permanent neurological deficit rate was 1.2%. Ultimately, 21.5% required revision surgery, most commonly for implant-related complications. Loss of correction in both the sagittal and coronal planes commonly occurred at follow-up. Five papers supplied validated patient-reported outcome measures, showing improvement in the mental health, self-image, and activity domains.

CONCLUSIONS

Data on the surgical outcomes of dystrophic scoliosis correction are heterogeneous and sparse. The perioperative complication rate appears to be high, although reported rates of neurological deficits appear to be lower than clinically observed and may be underreported. The incidence of implant-related failures requiring revision surgery is high. There is a great need for multicenter prospective studies of this complex type of deformity.

Awareness and agreement with neurofibromatosis care guidelines among U.S. neurofibromatosis specialists

Introduction

The neurofibromatoses (NF) are a group of rare, genetic diseases sharing a predisposition to develop multiple benign nervous system tumors. Given the wide range of NF symptoms and medical specialties involved in NF care, we sought to evaluate the level of awareness of, and agreement with, published NF clinical guidelines among NF specialists in the United States.

Methods

An anonymous, cross-sectional, online survey was distributed to U.S.-based NF clinicians. Respondents self-reported demographics, practice characteristics, awareness of seven NF guideline publications, and level of agreement with up to 40 individual recommendations using a 5-point Likert scale. We calculated the proportion of recommendations that each clinician rated “strongly agree”, and assessed for differences in guideline awareness and agreement by respondent characteristics.

Results

Sixty-three clinicians (49% female; 80% academic practice) across > 8 medical specialties completed the survey. Awareness of each guideline publication ranged from 53%-79% of respondents; specialists had higher awareness of publications endorsed by their medical professional organization (p < 0.05). The proportion of respondents who “strongly agree” with individual recommendations ranged from 17%-83%; for 16 guidelines, less than 50% of respondents “strongly agree”. There were no significant differences in overall agreement with recommendations based on clinicians’ gender, race, specialty, years in practice, practice type (academic/private practice/other), practice location (urban/suburban/rural), or involvement in NF research (p > 0.05 for all).

Conclusions

We identified wide variability in both awareness of, and agreement with, published NF care guidelines among NF experts. Future quality improvement efforts should focus on evidence-based, consensus-driven methods to update and disseminate guidelines across this multi-specialty group of providers. Patients and caregivers should also be consulted to proactively anticipate barriers to accessing and implementing guideline-driven care. These recommendations for improving guideline knowledge and adoption may also be useful for other rare diseases requiring multi-specialty care coordination.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02196-x.

Reliability of Handheld Dynamometry to Measure Focal Muscle Weakness in Neurofibromatosis Types 1 and 2

OBJECTIVE

To determine a suitable outcome measure for assessing muscle strength in neurofibromatosis (NF) type 1 and NF2 clinical trials, we evaluated the intraobserver reliability of handheld dynamometry (HHD) and developed consensus recommendations for its use in NF clinical trials.

METHODS

Patients ≥5 years of age with weakness in at least 1 muscle group by manual muscle testing (MMT) were eligible. Maximal isometric muscle strength of a weak muscle group and the biceps of the dominant arm was measured by HHD. An average of 3 repetitions per session was used as an observation, and 3 sessions with rest period between each were performed on the same day by a single observer. Intrasession and intersession intraclass correlation coefficients (ICCs) and coefficients of variation (CVs) were calculated to assess reliability and measurement error.

RESULTS

Twenty patients with NF1 and 13 with NF2 were enrolled; median age was 12 years (interquartile range [IQR] 9-17 years) and 29 years (IQR 22-38 years), respectively. By MMT, weak muscle strength ranged from 2-/5 to 4+/5. Biceps strength was 5/5 in all patients. Intersession ICCs for the weak muscles were 0.98 and 0.99 in the NF1 and NF2 cohorts, respectively, and for biceps were 0.97 and 0.97, respectively. The median CVs for average session strength were 5.4% (IQR 2.6%-7.3%) and 2.9% (IQR 2.0%-6.2%) for weak muscles and biceps, respectively.

CONCLUSION

HHD performed by a trained examiner with a well-defined protocol is a reliable technique to measure muscle strength in NF1 and NF2. Recommendations for strength testing in NF1 and NF2 trials are provided.

Slowing late infantile Batten disease by direct brain parenchymal administration of a rh.10 adeno-associated virus expressing CLN2

Late infantile Batten disease (CLN2 disease) is an autosomal recessive, neurodegenerative lysosomal storage disease caused by mutations in the CLN2 gene encoding tripeptidyl peptidase 1 (TPP1). We tested intraparenchymal delivery of AAVrh.10hCLN2, a nonhuman serotype rh.10 adeno-associated virus vector encoding human CLN2, in a nonrandomized trial consisting of two arms assessed over 18 months: AAVrh.10hCLN2-treated cohort of 8 children with mild to moderate disease and an untreated, Weill Cornell natural history cohort consisting of 12 children. The treated cohort was also compared to an untreated European natural history cohort of CLN2 disease. The vector was administered through six burr holes directly to 12 sites in the brain without immunosuppression. In an additional safety assessment under a separate protocol, five children with severe CLN2 disease were treated with AAVrh.10hCLN2. The therapy was associated with a variety of expected adverse events, none causing long-term disability. Induction of systemic anti-AAVrh.10 immunity was mild. After therapy, the treated cohort had a 1.3- to 2.6-fold increase in cerebral spinal fluid TPP1. There was a slower loss of gray matter volume in four of seven children by MRI and a 42.4 and 47.5% reduction in the rate of decline of motor and language function, compared to Weill Cornell natural history cohort (P < 0.04) and European natural history cohort (P < 0.0001), respectively. Intraparenchymal brain administration of AAVrh.10hCLN2 slowed the progression of disease in children with CLN2 disease. However, improvements in vector design and delivery strategies will be necessary to halt disease progression using gene therapy.

The Use of MEK Inhibitors in Neurofibromatosis Type 1-Associated Tumors and Management of Toxicities

Early-phase clinical trials using oral inhibitors of MEK, the mitogen-activated protein kinase kinase, have demonstrated benefit for patients with neurofibromatosis type 1 (NF1)-associated tumors, particularly progressive low-grade gliomas and plexiform neurofibromas. Given this potential of MEK inhibition as an effective medical therapy, the use of targeted agents in the NF1 population is likely to increase substantially. For clinicians with limited experience prescribing MEK inhibitors, concern about managing these treatments may be a barrier to use. In this manuscript, the Clinical Care Advisory Board of the Children's Tumor Foundation reviews the published experience with MEK inhibitors in NF1 and outlines recommendations for side-effect management, as well as monitoring guidelines. These recommendations can serve as a beginning framework for NF providers seeking to provide the most effective treatments for their patients. IMPLICATIONS FOR PRACTICE: Neurofibromatosis type 1 (NF1) clinical care is on the cusp of a transformative shift. With the success of recent clinical trials using MEK inhibitors, an increasing number of NF1 patients are being treated with MEK inhibitors for both plexiform neurofibromas and low-grade gliomas. The use of MEK inhibitors is likely to increase substantially in NF1. Given these changes, the Clinical Care Advisory Board of the Children's Tumor Foundation has identified a need within the NF1 clinical community for guidance for the safe and effective use of MEK inhibitors for NF1-related tumors. This article provides a review of the published experience of MEK inhibitors in NF1 and provides recommendations for monitoring and management of side effects.

The MEK inhibitor selumetinib reduces spinal neurofibroma burden in patients with NF1 and plexiform neurofibromas

BACKGROUND

Spinal neurofibromas (SNFs) in neurofibromatosis type 1 (NF1) can cause progressive spinal cord compression and neurological dysfunction. The MEK inhibitor selumetinib shrinks the majority of plexiform neurofibromas (PNs) in patients with NF1. We assessed the effect of selumetinib on SNF.

METHODS

Pediatric and adult patients with NF1 and inoperable PN participating in phase 2 studies of selumetinib for PN were included in this analysis if they had SNF and serial spine magnetic resonance imaging (MRI). Selumetinib was administered orally at the recommended dose of 25 mg/m2/dose twice daily (max 50 mg b.i.d.; 1 cycle = 28 days). We qualitatively assessed the effect of selumetinib on SNF-related spinal canal distortion, cerebrospinal fluid distribution, and spinal cord deformity on MRI.

RESULTS

Twenty-four patients (18 male), median age 16.9 years (range, 6.2-60.3), had SNF, 22 of which were associated with the same nerves as the target PN assessed on the clinical trial. Twenty patients had spinal cord deformity. Twenty-three patients completed at least 12 treatment cycles to date. Eighteen patients showed subtle to a marked improvement in SNF burden, 5 remained stable, and no worsening was observed during treatment.

CONCLUSIONS

This is the first study describing the effect of selumetinib on SNF. Of 24 patients, 18 exhibited some improvement of SNF burden on imaging. These findings suggest that selumetinib may prevent the worsening of cord compression, potentially reducing the need for surgical interventions in select patients or benefitting patients who do not have a surgical option. Prospective evaluation of the clinical benefit of selumetinib for SNF is warranted.

Comparison of hybrid 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging and positron emission tomography/computed tomography for evaluation of peripheral nerve sheath tumors in patients with neurofibromatosis type 1

Rapidly enlarging, painful plexiform neurofibromas (PN) in neurofibromatosis type 1 (NF1) patients are at higher risk for harboring a malignant peripheral nerve sheath tumor (MPNST). Fludeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has been used to support more invasive diagnostic and therapeutic interventions. However, PET/CT imparts an untoward radiation hazard to this population with tumor suppressor gene impairment. The use of FDG PET coupled with magnetic resonance imaging (MRI) rather than CT is a safer alternative but its relative diagnostic sensitivity requires verification. Ten patients (6 females, 4 males, mean age 27 years, range 8–54) with NF1 and progressive PN were accrued from our institutional NF Clinic. Indications for PET scanning included increasing pain and/or progressive disability associated with an enlarging PN on serial MRIs. Following a clinically indicated whole-body FDG PET/CT, a contemporaneous PET/MRI was obtained using residual FDG activity with an average time interval of 3–4 h FDG-avid lesions were assessed for both maximum standardized uptake value (SUVmax) from PET/CT and SUVmax from PET/MR and correlation was made between the two parameters. 26 FDG avid lesions were detected on both PET/CT and PET/MR with an accuracy of 100%. SUVmax values ranged from 1.4–10.8 for PET/CT and from 0.2-5.9 for PET/MRI. SUVmax values from both modalities demonstrated positive correlation (r = 0.45, P < 0.001). PET/MRI radiation dose was significantly lower (53.35% ± 14.37% [P = 0.006]). In conclusion, PET/MRI is a feasible alternative to PET/CT in patients with NF1 when screening for the potential occurrence of MPNST. Reduction in radiation exposure approaches 50% compared to PET/CT.

Creation of an international registry to support discovery in schwannomatosis

Schwannomatosis is a tumor suppressor syndrome that causes multiple tumors along peripheral nerves. Formal diagnostic criteria were first published in 2005. Variability in clinical presentation and a relative lack of awareness of the syndrome have contributed to difficulty recognizing affected individuals and accurately describing the natural history of the disorder. Many critical questions such as the mutations underlying schwannomatosis, genotype-phenotype correlations, inheritance patterns, pathologic diagnosis of schwannomatosis-associated schwannomas, tumor burden in schwannomatosis, the incidence of malignancy, and the effectiveness of current, or new treatments remain unanswered. A well-curated registry of schwannomatosis patients is needed to facilitate research in field. An international consortium of clinicians and scientists across multiple disciplines with expertise in schwannomatosis was established and charged with the task of designing and populating a schwannomatosis patient registry. The International Schwannomatosis Registry (ISR) was built around key data points that allow confirmation of the diagnosis and identification of potential research subjects to advance research to further the knowledge base for schwannomatosis. A registry with 389 participants enrolled to date has been established. Twenty-three additional subjects are pending review. A formal process has been established for scientific investigators to propose research projects, identify eligible subjects, and seek collaborators from ISR sites. Research collaborations have been created using the information collected by the registry and are currently being conducted. The ISR is a platform from which multiple research endeavors can be launched, facilitating connections between affected individuals interested in participating in research and researchers actively investigating a variety of aspects of schwannomatosis. © 2016 Wiley Periodicals, Inc.

Brain Region-Specific Degeneration with Disease Progression in Late Infantile Neuronal Ceroid Lipofuscinosis (CLN2 Disease)

BACKGROUND AND PURPOSE

Late infantile neuronal ceroid lipofuscinosis (CLN2 disease) is a uniformly fatal lysosomal storage disease resulting from mutations in the CLN2 gene. Our hypothesis was that regional analysis of cortical brain degeneration may identify brain regions that are affected earliest and most severely by the disease.

MATERIALS AND METHODS

Fifty-two high-resolution 3T MR imaging datasets were prospectively acquired on 38 subjects with CLN2. A retrospective cohort of 52 disease-free children served as a control population. The FreeSurfer software suite was used for calculation of cortical thickness.

RESULTS

An increased rate of global cortical thinning in CLN2 versus control subjects was the primary finding in this study. Three distinct patterns were observed across brain regions. In the first, subjects with CLN2 exhibited differing rates of cortical thinning versus age. This was true in 22 and 26 of 34 regions in the left and right hemispheres, respectively, and was also clearly discernable when considering brain lobes as a whole and Brodmann regions. The second pattern exhibited a difference in thickness from healthy controls but with no discernable change with age (9 left hemispheres, 5 right hemispheres). In the third pattern, there was no difference in either the rate of cortical thinning or the mean cortical thickness between groups (3 left hemispheres, 3 right hemispheres).

CONCLUSIONS

This study demonstrates that CLN2 causes differential rates of degeneration across the brain. Anatomic and functional regions that degenerate sooner and more severely than others compared with those in healthy controls may offer targets for directed therapies. The information gained may also provide neurobiologic insights regarding the mechanisms underlying disease progression.

Efficacy of local polymer-based and systemic delivery of the anti-glutamatergic agents riluzole and memantine in rat glioma models

OBJECT

The poor outcome of malignant gliomas is largely due to local invasiveness. Previous studies suggest that gliomas secrete excess glutamate and destroy surrounding normal peritumoral brain by means of excitotoxic mechanisms. In this study the authors assessed the effect on survival of 2 glutamate modulators (riluzole and memantine) in rodent glioma models.

METHODS

In an in vitro growth inhibition assay, F98 and 9L cells were exposed to riluzole and memantine. Mouse cerebellar organotypic cultures were implanted with F98 glioma cells and treated with radiation, radiation + riluzole, or vehicle and assessed for tumor growth. Safety and tolerability of intracranially implanted riluzole and memantine CPP:SA polymers were tested in F344 rats. The efficacy of these drugs was tested against the 9L model and riluzole was further tested with and without radiation therapy (RT).

RESULTS

In vitro assays showed effective growth inhibition of both drugs on F98 and 9L cell lines. F98 organotypic cultures showed reduced growth of tumors treated with radiation and riluzole in comparison with untreated cultures or cultures treated with radiation or riluzole alone. Three separate efficacy experiments all showed that localized delivery of riluzole or memantine is efficacious against the 9L gliosarcoma tumor in vivo. Systemic riluzole monotherapy was ineffective; however, riluzole given with RT resulted in improved survival.

CONCLUSIONS

Riluzole and memantine can be safely and effectively delivered intracranially via polymer in rat glioma models. Both drugs demonstrate efficacy against the 9L gliosarcoma and F98 glioma in vitro and in vivo. Although systemic riluzole proved ineffective in increasing survival, riluzole acted synergistically with radiation and increased survival compared with RT or riluzole alone.

Incidental parenchymal magnetic resonance imaging findings in the brains of patients with neurofibromatosis type 2

PURPOSE

Whereas T2 hyperintensities known as NF-associated bright spots are well described in patients with neurofibromatosis type I (NF-1), there is a paucity of data on incidental findings in patients with neurofibromatosis type II (NF-2). We aim to characterize unexplained imaging findings in the brains of patients with NF-2.

MATERIALS AND METHODS

This study is retrospective, HIPAA-compliant and approved by the institutional review board. 34 patients with NF-2 underwent brain magnetic resonance imaging (MRI) between January 2000 and December 2012. T2 and T1-weighted imaging characteristics, diffusion weighted imaging (DWI) characteristics, and enhancement patterns were analyzed by visual inspection. Clinical information at time of imaging was available for all patients. Neuropathologic data was available for one patient.

RESULTS

We found unexplained T2 hyperintensities present on initial imaging in 23/34 patients (67%). Of the 23 patients with unexplained MRI findings, 15 (65%) had wedge-shaped T2 hyperintensities in the subcortical white matter extending to the cortex suggestive of a cortical dysplasia. 3 additional cases (17%) had a lesion within the cerebellum suggestive of a neuronal migration anomaly. In one patient where the MRI was suggestive of focal cortical dysplasia, histopathologic analysis revealed dysplastic glial foci without other alterations of cortical architecture or other cytologic abnormalities.

CONCLUSION

Unexplained T2 hyperintensities occur frequently in patients with NF-2. While they may not be the NF-2 equivalent of NF-associated bright spots seen in NF-1, some of these T2 hyperintensities in patients with NF-2 may represent underlying disorders of neuronal migration. Further studies are needed to validate our findings.

Spectrum of ocular manifestations in CLN2-associated batten (Jansky-Bielschowsky) disease correlate with advancing age and deteriorating neurological function

Background

Late infantile neuronal ceroid lipofuscinosis (LINCL), one form of Batten’s disease is a progressive neurodegenerative disorder resulting from a CLN2 gene mutation. The spectrum of ophthalmic manifestations of LINCL and the relationship with neurological function has not been previously described.

Methods

Patients underwent ophthalmic evaluations, including anterior segment and dilated exams, optical coherence tomography, fluorescein and indocyanine green angiography. Patients were also assessed with the LINCL Neurological Severity Scale. Ophthalmic findings were categorized into one of five severity scores, and the association of the extent of ocular disease with neurological function was assessed.

Results

Fifty eyes of 25 patients were included. The mean age at the time of exam was 4.9 years (range 2.5 to 8.1). The mean ophthalmic severity score was 2.6 (range 1 to 5). The mean neurological severity score was 6.1 (range 2 to 11). Significantly more severe ophthalmic manifestations were observed among older patients (p<0.005) and patients with more severe neurological findings (p<0.03). A direct correlation was found between the Ophthalmic Severity Scale and the Weill Cornell Neurological Scale (p<0.002). A direct association was also found between age and the ophthalmic manifestations (p<0.0002), with older children having more severe ophthalmic manifestations.

Conclusions

Ophthalmic manifestations of LINCL correlate closely with the degree of neurological function and the age of the patient. The newly established LINCL Ophthalmic Scale may serve as an objective marker of LINCL severity and disease progression, and may be valuable in the evaluation of novel therapeutic strategies for LINCL, including gene therapy.

Vascular distribution of glioblastoma multiforme at diagnosis

Treatment of high-grade gliomas with selective intra-arterial (IA) administration of chemotherapies has been proposed, and utilized as a therapeutic modality. This approach offers the conceptual benefit of providing maximal delivery of the agent to the tumor bed, while potentially reducing systemic exposure to the agent. This retrospective study was designed to determine the vascular distribution of glioblastoma multiforme (GBM) at the time of diagnosis in an effort to determine what proportion of patients would likely be candidates for this approach. The preoperative MRI scans of 50 patients with GBM were analyzed and compared to published normative data of intracranial vascular distribution. Vascular distribution was determined by analyzing post-gadolinium axial and coronal T1 images, axial T2 images, and axial T2 images with an additional 1 cm margin (T2 + 1 cm) added in all dimensions. T1 analysis demonstrated 60% of tumors in a single vascular distribution. T2 analysis of these tumors reduced that number to 34%. When the T2 + 1 cm margin was utilized, only 6% of tumors were in a single vascular distribution. 66% of tumors were limited to the anterior circulation on T1 imaging but only 34% on T2 + 1 cm imaging. 30% of tumors were also within the distribution of the anterior choroidal artery. These findings suggest that the use of selective IA administration of agents is necessarily limited to a fraction of presenting patients or will require administration via multiple cerebral arteries.

Long-term expression and safety of administration of AAVrh.10hCLN2 to the brain of rats and nonhuman primates for the treatment of late infantile neuronal ceroid lipofuscinosis

Late infantile neuronal ceroid lipofuscinosis (LINCL), a fatal, lysosomal storage disorder caused by mutations in the CLN2 gene, results in a deficiency of tripeptidyl-peptidase I (TPP-I) activity in neurons. Our prior studies showed that delivery of the human CLN2 cDNA directly to the CNS, using an adeno-associated virus serotype 2 (AAV2) vector, is safe in children with LINCL. As a second-generation strategy, we have demonstrated that AAVrh.10hCLN2, a rhesus-derived AAV vector, mediates wide distribution of TPP-I through the CNS in a murine model. This study tests the hypothesis that direct administration of AAVrh.10hCLN2 to the CNS of rats and nonhuman primates at doses scalable to humans has an acceptable safety profile and mediates significant CLN2 expression in the CNS. A dose of 10(11) genome copies (GC) was administered bilaterally to the striatum of Sprague Dawley rats with sacrifice at 7 and 90 days with no significant impact except for mild vector-related histopathological changes at the site of vector administration. A dose of 1.8×10(12) GC of AAVrh.10hCLN2 was administered to the CNS of 8 African green monkeys. The vector-treated monkeys did not differ from controls in any safety parameter except for mild to moderate white matter edema and inflammation localized to the administration sites of the vector. There were no clinical sequelae to these localized findings. TPP-I activity was >2 SD over background in 31.7±8.1% of brain at 90 days. These findings establish the dose and safety profile for human clinical studies for the treatment of LINCL with AAVrh.10hCLN2.

Assessment of disease severity in late infantile neuronal ceroid lipofuscinosis using multiparametric MR imaging

BACKGROUND AND PURPOSE

LINCL is a uniformly fatal lysosomal storage disease resulting from mutations in the CLN2 gene that encodes for tripeptidyl peptidase 1, a lysosomal enzyme necessary for the degradation of products of cellular metabolism. With the goal of developing quantitative noninvasive imaging biomarkers sensitive to disease progression, we evaluated a 5-component MR imaging metric and tested its correlation with a clinically derived disease-severity score.

MATERIALS AND METHODS

MR imaging parameters were measured across the brain, including quantitative measures of the ADC, FA, nuclear spin-spin relaxation times (T2), volume percentage of CSF (%CSF), and NAA/Cr ratios. Thirty MR imaging datasets were prospectively acquired from 23 subjects with LINCL (2.5-8.4 years of age; 8 male/15 female). Whole-brain histograms were created, and the mode and mean values of the histograms were used to characterize disease severity.

RESULTS

Correlation of single MR imaging parameters against the clinical disease-severity scale yielded linear regressions with R2 ranging from 0.25 to 0.70. Combinations of the 5 biomarkers were evaluated by using PCA. The best combination included ADC, %CSF, and NAA/Cr (R2=0.76, P<.001).

CONCLUSIONS

The multiparametric disease-severity score obtained from the combination of ADC, %CSF, and NAA/Cr whole-brain MR imaging techniques provided a robust measure of disease severity, which may be useful in clinical therapeutic trials of LINCL in which an objective assessment of therapeutic response is desired.

Consensus recommendations to accelerate clinical trials for neurofibromatosis type 2

PURPOSE

Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disorder associated primarily with bilateral schwannomas seen on the superior vestibular branches of the eighth cranial nerves. Significant morbidity can result from surgical treatment of these tumors. Meningiomas, ependymomas, and other benign central nervous system tumors are also common in NF2. The lack of effective treatments for NF2 marks an unmet medical need.

EXPERIMENTAL DESIGN

Here, we provide recommendations from a workshop, cochaired by Drs. D. Gareth Evans and Marco Giovannini, of 36 international researchers, physicians, representatives of the biotechnology industry, and patient advocates on how to accelerate progress toward NF2 clinical trials.

RESULTS

Workshop participants reached a consensus that, based on current knowledge, the time is right to plan and implement NF2 clinical trials. Obstacles impeding NF2 clinical trials and how to address them were discussed, as well as the candidate therapeutic pipeline for NF2.

CONCLUSIONS

Both phase 0 and phase II NF2 trials are near-term options for NF2 clinical trials. The number of NF2 patients in the population remains limited, and successful recruitment will require ongoing collaboration efforts between NF2 clinics.

A neurologic presentation of familial hemophagocytic lymphohistiocytosis which mimicked septic emboli to the brain

Familial hemophagocytic lymphohistiocytosis is an inherited deficiency of natural killer cell function and excessive cytokine activity, which predominantly presents in early childhood. The initial symptoms of familial hemophagocytic lymphohistiocytosis are often nonspecific but may be predominantly neurologic. The case presented here describes an 18-month-old boy who initially presented with fever, encephalopathy, and hemiparesis. He had innumerable brain lesions visualized on magnetic resonance imaging scans. An infectious etiology was excluded, and brain, liver, and bone marrow biopsies were nonspecific but consistent with hemophagocytic lymphohistiocytosis. Cells were sent for flow cytometry perforin analysis, which demonstrated defective natural killer cell function. A diagnosis of familial hemophagocytic lymphohistiocytosis was confirmed by mutation analysis and decreased expression of the perforin gene, in the patient and immediate family members. These results showed the patient to be a compound heterozygote for perforin mutations. His case illustrates the potential for a fulminant neurological presentation of familial hemophagocytic lymphohistiocytosis with widespread lesions in the brain.

Neurofibromatosis types 1 and 2

BACKGROUND

Neurofibromatosis types 1 and 2 (NF1 and NF2) are autosomal dominant neurocutaneous disorders with some similarities and many differences. They are frequently discussed together and often confused for one another by clinicians. Both disorders have widely variable presentations and degrees of severity. A thorough understanding of these complex disorders is essential for proper medical management, anticipatory care, and patient education.

REVIEW SUMMARY

In this article, the clinical features, genetics, pathogenesis, and management of neurofibromatosis types 1 and 2 are reviewed and compared.

CONCLUSIONS

NF1 and NF2 are complex genetic disorders with numerous manifestations and wide phenotypic variability. The complex nature of these disorders requires coordinated multidisciplinary care.

Inverse correlation between cerebral blood flow measured by continuous arterial spin-labeling (CASL) MRI and neurocognitive function in children with sickle cell anemia (SCA)

Overt stroke, clinically "silent" cerebral infarct, and neurocognitive impairment are frequent complications of sickle cell anemia (SCA). Current imaging techniques have limited sensitivity and specificity to identify children at risk for neurocognitive impairment. We prospectively evaluated 24 children with SCA with a neurologic exam, complete blood count, transcranial Doppler ultrasound (TCD), measurement of intelligence quotient (IQ), and magnetic resonance imaging (MRI) with measurement of cerebral blood flow (CBF) using continuous arterial spin-labeling (CASL) MRI. Average CBF to gray matter was 112 +/- 36 mL/100 g/min. We identified a strong inverse relationship between performance IQ and CBF (-1.5 points per 10 mL/100 g/min increase in CBF, P = .013). Elevated steady-state white blood cell count (> or = 14 x 10(9)/L [14,000/microL]) was associated with lower full scale IQ (86 +/- 9 vs 99 +/- 10, P = .005). CASL MRI may identify children with neurocognitive impairment, before damage is evident by structural MRI or TCD.

Panuveitis in association with pseudotumor cerebri

We report a case of an 11-year-old girl with bilateral panuveitis in association with pseudotumor cerebri. The patient underwent complete ophthalmologic, neurologic, and laboratory evaluations and was treated with therapy for pseudotumor cerebri. The patient met the diagnostic criteria for pseudotumor cerebri and also had panuveitis. Symptoms and findings of pseudotumor cerebri and panuveitis improved significantly after combination therapy of oral acetazolamide and weight reduction. The index case illustrates that pseudotumor cerebri can be associated with panuveitis. Therapy for pseudotumor cerebri might also help with the resolution of uveitis.

The life span of new neurons in a song control nucleus of the adult canary brain depends on time of year when these cells are born

The number of high vocal center (HVC) neurons labeled in adult male canaries by systemic injections of [3H]thymidine depended on season and survival time. This was true for HVC neurons projecting to the robust nucleus of the archistriatum and for other HVC neurons that could not be retrogradely filled from the robust nucleus of the archistriatum. Birds injected in October and killed 40 days later had twice as many labeled HVC neurons as birds injected in May and killed 40 days later. However, this difference became much larger (5 times) when the birds were allowed to survive for 4 months. Whereas more than half of the spring-born neurons disappeared between 40 days and 4 months, there was no reduction in the number of fall-born neurons present at the 4-month survival point. We infer that seasonal variables affect the life span of HVC neurons born in adulthood.

Offense produced by chemical stimulation of the anterior hypothalamus of the rat

Offense behavior, including bite-and-kick attack, was obtained by microinjections of picrotoxin into the anterior hypothalamus of the rat. This is the first time that it has been possible to obtain offense by chemical stimulation of the brain, and the localization is more precise than that obtained with electrical stimulation. Mounting behavior and mounting by the opponent were also obtained from the anterior hypothalamus, the former corresponding to results obtained by previous studies using electrical stimulation. Other behaviors obtained from the hypothalamus included locomotion and circling, social and self-grooming, upright posture and boxing, digging, feeding, and leaping.