BACKGROUND Effective medical therapies are lacking for the treatment of neurofibromatosis type 1– related plexiform neurofibromas, which are characterized by elevated RAS–mitogen-activated protein kinase (MAPK) signaling. METHODS We conducted a phase 1 trial of selumetinib (AZD6244 or ARRY-142886), an oral selective inhibitor of MAPK kinase (MEK) 1 and 2, in children who had neurofibromatosis type 1 and inoperable plexiform neurofibromas to determine the maximum tolerated dose and to evaluate plasma pharmacokinetics. Selumetinib was administered twice daily at a dose of 20 to 30 mg per square meter of body-surface area on a continuous dosing schedule (in 28-day cycles). We also tested selumetinib using a mouse model of neurofibromatosis type 1–related neurofibroma. Response to treatment (i.e., an increase or decrease from baseline in the volume of plexiform neurofibromas) was monitored by using volumetric magnetic resonance imaging analysis to measure the change in size of the plexiform neurofibroma. RESULTS A total of 24 children (median age, 10.9 years; range, 3.0 to 18.5) with a median tumor volume of 1205 ml (range, 29 to 8744) received selumetinib. Patients were able to receive selumetinib on a long-term basis; the median number of cycles was 30 (range, 6 to 56). The maximum tolerated dose was 25 mg per square meter (approximately 60% of the recommended adult dose). The most common toxic effects associated with selumetinib included acneiform rash, gastrointestinal effects, and asymptomatic creatine kinase elevation. The results of pharmacokinetic evaluations of selumetinib among the children in this trial were similar to those published for adults. Treatment with selumetinib resulted in confirmed partial responses (tumor volume decreases from baseline of ≥20%) in 17 of the 24 children (71%) and decreases from baseline in neurofibroma volume in 12 of 18 mice (67%). Disease progression (tumor volume increase from baseline of ≥20%) has not been observed to date. Anecdotal evidence of decreases in tumor-related pain, disfigurement, and functional impairment was observed. CONCLUSIONS Our early-phase data suggested that children with neurofibromatosis type 1 and inoperable plexiform neurofibromas benefited from long-term dose-adjusted treatment with selumetinib without having excess toxic effects. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01362803.)

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A B S T R A C T PurposeAtypical teratoid rhabdoid tumor (ATRT) of the CNS is a highly malignant neoplasm primarily affecting young children, with a historic median survival ranging from 6 to 11 months. Based on a previous pilot series, a prospective multi-institutional trial was conducted for patients with newly diagnosed CNS ATRT. Patients and MethodsTreatment was divided into five phases: preirradiation, chemoradiation, consolidation, maintenance, and continuation therapy. Intrathecal chemotherapy was administered, alternating intralumbar and intraventricular routes. Radiation therapy (RT) was prescribed, either focal (54 Gy) or craniospinal (36 Gy, plus primary boost), depending on age and extent of disease at diagnosis. ResultsBetween 2004 and 2006, 25 patients were enrolled; 20 were eligible for evaluation. Median age at diagnosis was 26 months (range, 2.4 months to 19.5 years). Gross total resection of the primary tumor was achieved in 11 patients. Fourteen patients had M0 disease at diagnosis, one patient had M2 disease, and five patients had M3 disease. Fifteen patients received radiation therapy: 11 focal and four craniospinal. Significant toxicities, in addition to the expected, included radiation recall (n ϭ 2) and transverse myelitis (n ϭ 1). There was one toxic death. Of the 12 patients who were assessable for chemotherapeutic response (pre-RT), the objective response rate was 58%. The objective response rate observed after RT was 38%. The 2-year progression-free and overall survival rates are 53% Ϯ 13% and 70% Ϯ 10%, respectively. Median overall survival has not yet been reached. ConclusionThis intensive multimodality regimen has resulted in a significant improvement in time to progression and overall survival for patients with this previously poor-prognosis tumor.

Authors' Contributions 1.JF -Substantial contributions to acquisition, analysis and interpretation of data, drafting the work, final approval of the version to be published and agreement to be accountable for all aspects of the work. 2.AO -Substantial contributions to the conception and design of the work, analysis and interpretation of data, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 3.TP -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 4.SW -Substantial contributions to the conception and design of the work, analysis and interpretation of data, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 5.AL -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 6.NL -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 7.AB -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 8.RP -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 9.LK -Substantial revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 10.SG -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 11.IP -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 12.IQ -Substantial contributions to revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable for all aspects of the work. 13.RJ -Substantial contributions to the conception and design of the work, revising it critically for important intellectual content, final approval of the version to be published and agreement to be accountable ...

Optic pathway gliomas (OPGs) occur in 15%-20% of children with neurofibromatosis type 1 (NF1); up to half become symptomatic. There is little information regarding ophthalmologic outcomes after chemotherapy. A retrospective multicenter study was undertaken to evaluate visual outcomes following chemotherapy for NF1-associated OPG, to identify risks for visual loss, and to ascertain indications for treatment. Subjects included children undergoing initial treatment for OPGs with chemotherapy between January 1997 and December 2007. Of 115 subjects, visual acuity (VA) decline and tumor progression were the primary reasons to initiate treatment, although there were significant differences in the pattern of indications cited among the institutions. Eighty-eight subjects and 168 eyes were evaluable for VA outcome. At completion of chemotherapy, VA improved (32% of subjects), remained stable (40%), or declined (28%). Tumor location was the most consistent prognostic factor for poor VA outcome. There was poor correlation between radiographic and VA outcomes. Although visual outcomes for NF1-associated OPG are not optimal, approximately one-third of children regain some vision with treatment. Since radiographic outcomes do not predict visual outcomes, their use as the primary measure of treatment success is in question. The lack of consensus regarding the indications for treatment underlines the need for better standardization of care. Future clinical trials for OPG require standardized visual assessment methods and clear definitions of visual outcomes.

Velocity measurements in a 51 mm diameter turbulent jet are presented. The measurement programme is conducted in two parts. The first part is devoted to the validation of laser velocimeter (LV) data. This consists of comparative measurements with the LV and a hot-wire anemometer. The second part consists of a survey of the jet flow field at Mach 0·28, 0·90, and 1·37 under ambient temperature conditions. Radial and centre-line distributions of the axial and radial, mean and fluctuating velocities are obtained. The distributions indicate a decrease in the spreading rate of the mixing layer with increasing Mach number and a corresponding lengthening of the potential core. The results further indicate that these two parameters vary with the square of the jet Mach number. Radial distributions collapse when plotted in terms of ση*, where σ = 10.7/(1 - 0.273 MJ2) and η* = (r − r0·5)/x. This is true for distributions in planes located as far downstream as two potential core lengths. The collapsed data of mean velocity can be approximated by a Görtler error function profile: \[ U/U_J = 0.5[1-{\rm erf}(\sigma\eta^{*})]. \] Centre-line distributions at various Mach numbers also collapse if plotted in terms of x/xc, xc being the potential core length. A general equation for the collapsed data of mean velocity is given by: U/UJ = 1 - exp{1.35/(1 - x/xc)}, for the range of Mach numbers 0·3-1·4, where xc = 4.2 + 1.1 MJ2.

Pediatric low-grade gliomas encompass a heterogeneous set of tumors of different histologies. Cerebellar pilocytic astrocytomas occur most frequently followed by supratentorial diffuse fibrillary astrocytomas. Recent research has implicated activation of the RAS/RAF/MEK pathway in tumorigenesis of these tumors. Surgery is the mainstay of therapy. Overall survival rates for patients whose tumors are completely resected are 90% or greater, 10 years from diagnosis. Conversely, most optic pathway/hypothalamic, deep midline, and brain stem gliomas have minimal potential for resection; these tumors can be difficult to treat and deserve special attention. Combination chemotherapy is currently recommended as front-line adjuvant treatment for progressive or recurrent tumors. Second-line radiotherapy can also improve overall survival but is associated with more frequent and significant neurocognitive, endocrine, and other long-term toxicities.Keywords low-grade; glioma; astrocytoma; pilocytic; fibrillary Pediatric low-grade gliomas are a heterogeneous set of tumors. They encompass tumors of astrocytic, oligodendroglial, and mixed glial-neuronal histology. Although their clinical behavior can vary, the majority of low-grade gliomas are indolent and do not undergo malignant transformation. Case reports have even described spontaneous regression of some tumors. 1,2 This is in contrast to adult low-grade gliomas that have a more aggressive phenotype. One reason for the differences between the 2 populations may be the different frequencies of histological subtypes. Pilocytic astrocytomas infrequently occur in adults but are the leading histology in children. Conversely, diffuse gemistocytic astrocytomas, which have been associated with an increased tendency toward malignant progression, are rarely found in children. 3 Low-grade gliomas are estimated to account for anywhere from 30% to 50% of central nervous system tumors in children. [4][5][6] Discussion of gliomas can be confusing as it is a descriptive and not a pathological term. Tumors are classified according to the World Health Organization (WHO) criteria, most recently published in 2007, which describes their histological features and also provides a grading or "malignancy scale." 3 Low-grade gliomas encompass grade 1 and grade 2 tumors (Table 1). 3 Grading is based on a number of factors including presence of necrosis, giant cells, mitosis, endothelial proliferation, hyperchromatic nuclei, and pleomorphic cells. These findings can be subjective, and retrospective studies have documented significant Pediatric low-grade gliomas can be difficult to categorize as they can occur anywhere in the central nervous system and comprise multiple different tumor histologies. Historically, the cerebellum is the most prevalent location, and cerebellar low-grade gliomas account for 15% to 25% of all pediatric central nervous system tumors. They are followed by hemispheric (cerebral) gliomas (10%-15%), gliomas of the deep midline structures (10%-15%), optic pathway gliomas (5%)...

Sorafenib produced unexpected and unprecedented acceleration of tumor growth in children with PLGA, irrespective of NF1 or tumor BRAF status. In vitro studies with sorafenib indicate that this effect is likely related to paradoxical ERK activation. Close monitoring for early tumor progression should be included in trials of novel agents that modulate signal transduction.