bluuebunny/crossref_metadata_2025 huggingface dataset:
DIPG-17. BIOPSY-PROVEN DIFFUSE MIDLINE GLIOMA IN ADOLESCENTS AND YOUNG ADULTS
Authors: Tanaka Shota , Takayanagi Shunsaku , Shinya Yuki , Kawashima Mariko , Shin Masahiro , Nakatomi Hirofumi , Saito Nobuhito
Published: December 2020

INTRODUCTION

Diffuse midline glioma (DMG) mostly affects young children. The newly-introduced disease entity DMG, H3K27M-mutant uniformly portends poor prognosis, and therefore that in the pons is usually treated based upon radiological diagnosis without histological confirmation. DMG is rarer in adolescents and young adults (AYA), and remains poorly characterized. In this study, we sought to investigate the clinical, pathological, and molecular profiles of DMG in AYA generation.

METHODS

Patients of age between 16 and 39 undergoing biopsy at the University of Tokyo Hospital between 2003 and 2019 were included in the study. Clinical data and images were retrospectively reviewed. Genetic analyses were performed in cases with abundant tissues.

RESULTS

Ten patients included 8 brainstem and 2 thalamic DMG. The median age was 25 years (range, 19–38). Pathological diagnosis was DMG, H3K27M-mutant in 3 patients, glioblastoma, IDH-mutant in 1, anaplastic astrocytoma, IDH-wildtype in 4, diffuse astrocytoma, IDH-mutant in 1, and diffuse astrocytoma, IDH-wildtype in 1. Genetic analyses detected H3F3A-K27M mutation in 2, HIST1H3B-K27M mutation in 1, IDH1-R132H mutation in 1, and IDH1-R132S mutation in 1. With a median follow-up of 23 months (range, 2–61), only 3 patients died 29–61 months after diagnosis, and the remaining 7 patients survived for 2–59 months. Neither IDH1 mutation nor H3K27M mutation was associated with survival in this series.

CONCLUSION

Survival of AYA patients with DMG was seemingly variable with some long survivors. H3K27M mutation was present in a subset of patients. A further study is warranted to correlate molecular profile with clinical pictures including patient survival.
DIPG-22. DISSECTING THE ONCOGENIC ROLE OF FOXR2 IN DIFFUSE INTRINSIC PONTINE GLIOMA
Authors: Tsai Jessica W , Patel Smruti K , Bear Heather , Dubois Frank , Khadka Prasidda , Lu Sophie , Gonzalez Elizabeth , Ligon Keith , Bandopadhayay Pratiti , Phoenix Timothy N
Published: December 2020

BACKGROUND

Diffuse intrinsic pontine gliomas (DIPGs) pose particular challenges for treatment. We recently completed a genomic analysis of close to 200 DIPGs and high-grade gliomas. We identified that nearly 10% of all DIPGs have increased expression of the fork head domain transcription factor FOXR2. We hypothesize that FOXR2 accelerates gliomagenesis in histone mutant DIPGs and represents a previously unexplored therapeutic target.

METHODS

To determine whether FOXR2 is sufficient to mediate gliomagenesis, we applied an integrative genomics approach using both in vitro and in vivo DIPG models: mouse neural stem cell models expressing FOXR2, in vivo mouse models using in utero brainstem electroporation, patient-derived DIPG cell lines, and RNA sequencing analysis of human and mouse tumors expressing FOXR2.

RESULTS

Our data shows that FOXR2 indeed is an oncogene that rapidly accelerates gliomagenesis using an in vivo brainstem in utero electroporation model of DIPG. In human tumors, increased FOXR2 expression is mutually exclusive with MYC amplification suggesting functional redundancy. In vivo, FOXR2 results in large brainstem gliomas and rapid neurologic decline of animals. Transcriptional profiling of these tumors demonstrates activation of MYC signaling pathways. In vitro, we have further identified patient-derived cell lines with increased expression of FOXR2.

CONCLUSION

FOXR2 is sufficient to enhance gliomagenesis and represents a previously understudied therapeutic target for patients with the devastating disease DIPG.
DIPG-25. KETOGENIC DIET IN DIFFUSE INTRINSIC PONTINE GLIOMA IN CHILDREN: A RETROSPECTIVE STUDY INVESTIGATING THE FEASIBILITY
Authors: Perez Alexandre , Nathan Janak , El-Ayadi Moatasem , Korff Christian , Ansari Marc , von Bueren André
Published: December 2020

PURPOSE

Diffuse Intrinsic Pontine Glioma (DIPG) is one of the most devastating diseases amongst children with cancer, thus novel strategies are urgently needed. We aimed to retrospectively evaluate the feasibility of the carbohydrate restricted ketogenic diet (KD) in DIPG patients.

METHODS

Searches of MEDLINE and Embase identified four publications meeting the inclusion criteria (diagnosis of DIPG and exposition to a KD ≥ 3 months). One additional case was identified by contact with experts. The minimal feasibility criteria were defined as the ability to use the KD for ≥ 3 months. Individual patient data were extracted from the publications or obtained from investigators.

RESULTS

Five patients (males, n=3; median age 4.4 years; range, 2.5–17 years) met the inclusion criteria (one patient – identified and not included - was on KD < 3 months due to disease progression). Further feasibility analyses showed a duration of the KD of ≥ 3 months and less than 7 months (n=2), > 7 months and less than 1 year (n= 2), and two years (n=1), respectively.

CONCLUSION

These results – based on a small patient population – suggest that the KD appears to be a feasible treatment option for children with DIPG. The potential duration of the KD is limited by the aggressive clinical behavior of DIPG. The safety analysis is currently being retrospectively assessed. These data should encourage further studies on a larger scale; ideally assessing the impact of the KD in DIPG patients in a randomized controlled trial.
DIPG-26. THERAPEUTIC EFFECTS OF RADIOTHERAPY WITH CONCOMITANT AND ADJUVANT TEMOZOLOMIDE VERSUS RADIOTHERAPY WITH CONCOMITANT TEMOZOLOMIDE ALONE IN CHILDREN WITH DIPG: A SINGLE-CENTER EXPERIENCE WITH 82 CASES
Authors: Lai Mingyao , Li Juan , Hu Qingjun , Zhou Jiangfen , Li Shaoqun , Wen Lei , Zhou Zhaoming , Zhou Cheng , Wang Lichao , Shan Changguo , Zhang Yangqiong , Luo Rishun , Cai Linbo
Published: December 2020

OBJECTIVE

To retrospectively analyze the therapeutic effects of radiotherapy with concomitant and adjuvant temozolomide versus radiotherapy with concomitant temozolomide alone for pediatric diffuse intrinsic pontine glioma (DIPG), and to evaluate the value of temozolomide in the treatment of pediatric DIPG.

METHODS

The clinical data of children with confirmed DIPG in Guangdong Sanjiu Brain Hospital between January 1, 2010 and December 30, 2019 were collected. The inclusive criteria included (1) receiving a total radiotherapy dose of 54 Gy in 27 fractions, (2) treated with concomitant temozolomide chemotherapy, and (3) with or without adjuvant temozolomide chemotherapy.

RESULTS

A total of 82 pediatric patients were eligible for the study, with a median age of 7 years (range 2–16 years). The median follow-up was 8.6 months (range 2–28 months) and the median survival time was 9.4 months. The median survival time of 66 patients treated with radiotherapy with concomitant and adjuvant temozolomide was 9.8 months, longer than 7.5 months of the other 16 patients treated with radiotherapy with concomitant temozolomide alone, with statistical differences (P=0.010). Moreover, bevacizumab and nimotuzumab didn’t bring survival benefits to patients with disease recurrence or progression. Hematological toxicity (Grade IV) was not found.

CONCLUSION

Radiotherapy with concomitant and adjuvant temozolomide prolongs the survival time of children with DIPG.
DIPG-37. PREDICTING OUTCOME IN CHILDHOOD DIFFUSE MIDLINE GLIOMAS USING MAGNETIC RESONANCE IMAGING BASED TEXTURE ANALYSIS
Authors: Szychot Elwira , Youssef Adam , Ganeshan Balaji , Endozo Raymond , Hyare Harpreet , Gains Jenny , Shankar Ananth , Mankad Kshitij
Published: December 2020

BACKGROUND

Diffuse midline gliomas (DMG) are aggressive brain tumours with 10% overall survival (OS) at 18 months. Predicting OS will help refine treatment strategy in this patient group. MRI based texture analysis (MRTA) is a novel technique that provides objective information about spatial arrangement of MRI signal intensity and has potential as an imaging biomarker. OBJECTIVES: To investigate MRTA in predicting OS in childhood DMG.

METHODS

Retrospective study of patients diagnosed with DMG, based on radiological features, treated at our institution 2007–2017. MRIs were accomplished at diagnosis and 6 weeks after radiotherapy (54Gy in 30 fractions). MRTA, performed using TexRAD software, on T2W sequence and Apparent Diffusion Coefficient (ADC) maps encapsulated tumour in the largest single axial plane. MRTA comprised filtration-histogram technique using statistical and histogram metrics for quantification of texture. Kaplan-Meier analysis determined association of MRI texture parameters with OS.

RESULTS

32 children 2–14 years (median 7 years) were included. MRTA was undertaken on T2W (n=32) and ADC (n=22). MRTA on T2W was better at prognosticating than on ADC maps. Children with homogenous tumour texture, at medium scale on baseline T2W MRI, had worse prognosis (mean p=0.0098, SD p=0.0115, entropy p=0.0422, mean of positive pixels (MPP) p=0.0051, kurtosis p=0.0374). MPP was the most significant texture parameter. Median survival in this group as identified by MRTA (medium texture, MPP) was 7.5 months versus 17.5 months.

CONCLUSIONS

DMG with more homogeneous texture on diagnostic MRI is associated with worse prognosis. MPP texture parameter is the most predictive of OS in childhood DMG.
DIPG-41. DISSECTING THE MECHANISTIC BASIS FOR ACVR1 AND PIK3CA MUTATION CO-OCCURRENCE IN DIFFUSE MIDLINE GLIOMAS USING GENETICALLY ENGINEERED MOUSE MODELS
Authors: Wu Annette , Mak Tak , Fortin Jerome
Published: December 2020

Diffuse midline gliomas (DMGs) are aggressive childhood brain tumors with a dismal prognosis. Most of these tumors carry K27M mutations in histone H3-encoding genes, particularly H3F3A and HIST1H3B. In addition, activating mutations in ACVR1 and PIK3CA co-occur in a subset of DMGs. To understand how these lesions drive the development of DMGs, we generated genetically engineered mouse models in which Acvr1G328V, Hist1h3bK27M, and Pik3caH1047R are targeted to the OLIG2-expressing cell lineage. Animals carrying Acvr1G328V and Pik3caH1047R, with (“AHPO”) or without (“APO”) Hist1h3bK27M, developed high-grade diffuse gliomas involving midline and forebrain regions. Neither Acvr1G328V nor Pik3caH1047R drove tumorigenesis by themselves, but Acvr1G328V was sufficient to cause oligodendroglial differentiation arrest, pointing to a role in the earliest stages of gliomas formation. Transcriptomic analyses of AHPO and APO tumors indicated a predominantly proneural and oligodendrocyte precursor-like gene expression signature, consistent with the corresponding human pathology. Genes encoding transcription factors (TFs) with dual roles in controlling glial and neuronal differentiation were upregulated in tumors. Some of these genes were mildly induced by Acvr1G328V alone. Functional experiments using CRISPR/Cas9-mediated gene editing in patient-derived cell lines confirmed a role for some of these TFs in controlling DMG cell fitness. Overall, our results suggest that Pik3caH1047R consolidates Acvr1G328V-induced glial differentiation arrest to drive DMG development and progression.
DIPG-52. PHASE I CLINICAL TRIAL OF ONC201 IN PEDIATRIC H3 K27M-MUTANT GLIOMA OR NEWLY DIAGNOSED DIPG
Authors: Gardner Sharon , Tarapore Rohinton , Allen Jeffrey , Zaky Wafik , Odia Yazmin , Hall Matthew , Daghistani Doured , Khatib Ziad , Koschmann Carl , Aguilera Dolly , MacDonald Tobey , Fouladi Maryam , McGovern Susan , Kline Cassie , Vitanza Nicholas , Lu Guangrong , Merdinger Krystal , Oster Wolfgang , Allen Joshua , Khatua Soumen
Published: December 2020

H3 K27M-mutant gliomas often manifest as midline gliomas, have a dismal prognosis, and have no effective treatments. ONC201 efficacy has been shown in high-grade glioma preclinical models and durable responses with single agent ONC201 have been reported in adults with recurrent H3 K27M-mutant gliomas. These observations led to a Phase I pediatric clinical trial of ONC201 dosed by body weight. This multi-center, open-label, 3 + 3 dose-escalation and dose-expansion clinical trial (NCT03416530) for H3 K27M-mutant glioma or non-biopsied DIPG has 6 arms: arms A and E determine the RP2D in pediatric post-radiation (recurrent or not-recurrent) H3 K27M-mutant glioma patients with ONC201 administered as an oral capsule as well as a liquid formulation, respectively. Both arms have completed accrual. The study is currently enrolling newly diagnosed DIPG patients to determine the RP2D for ONC201 in combination with radiation (arm B). Dedicated assessment of intratumoral ONC201 concentrations in midline gliomas patients (arm C) and the effects of ONC201 in H3K27M DNA levels in circulating CSF (arm D) are currently enrolling patients. ONC201 as a single agent in patients with progressive H3K27M mutant tumors following irradiation (excluding DIPG/spinal cord tumors) was recently opened (arm F). Once the RP2D is confirmed, there is a dose-expansion cohort to confirm the safety, radiographic efficacy and survival with ONC201. The primary endpoints of arms A, B, and E have been established with the RP2D of 625mg scaled by body weight as a capsule or liquid formulation administered alone or in combination with radiation without incidence of dose-limiting toxicity.
DIPG-57. TRANSCRIPTOMIC AND PROTEOMIC ANALYSES OF DIPG RESPONSE TO ONC201
Authors: Sridharan Sreepradha , Harmanci Arif , Sharma Ajay , Lai Yanlai , Kennis Bridget , Dobson Tara , Swaminathan Jyothishmathi , Haltom Amanda , Khatua Soumen , Tarapore Rohinton , Allen Joshua , Cheng Donghang , Zaky Wafik , Gopalakrishnan Vidya
Published: December 2020

Diffuse Intrinsic Pontine Glioma (DIPG) is an incurable pediatric brain tumor. Current standard of care has shown no improvements in survival. Here, we report our study of ONC201, a first-in-class small molecule developed by Oncoceutics, Inc., against a panel of DIPG cells in vitro and in mouse orthotopic models. ONC201 inhibits signaling through dopamine receptor D2 (DRD2), a G protein-coupled receptor (GPCR). MTT assays revealed a delayed but more robust response to ONC201, as measured by IC50 values, in DIPGs with histone H3.3-K27M expression compared to cells expressing wildtype (WT) or K27M mutant histone H3.1. Interestingly, transcriptomic profiling identified an association of this response delay with an elevation of genes controlling the cellular unfolded protein response, lysosomal and vacuole organization, and a decline in nucleic acid biosynthetic genes. These cells were also more committed to neuronal and oligodendrocytic lineage specification. By contrast, WT-H3 DIPGs that survived ONC201 treatment were stem-like and exhibited altered expression of genes controlling cell proliferation and apoptosis induction, respectively. Single cell proteomics validated the increase in anti-apoptotic proteins in these cells. Intraperitoneal administration of ONC201 for 7-weeks in mice bearing pontine xenografts of histone H3.1-K27M mutant DIPGs, caused a complete blockade of tumor growth relative to untreated controls. However, identical treatment of animals with forebrain tumors resulted only in a partial reduction in tumor burden, suggesting that the tumor microenvironment may be involved in the differential effect. These data indicate that tumor intrinsic and extrinsic factors may contribute to the response of DIPG tumors to ONC201.
DIPG-72. LONG-TERM SURVIVAL OF A CLASSIC DIFFUSE INTRINSIC PONTINE GLIOMA TREATED WITH NIMOTUZUMAB
Authors: Epelman Sidnei , Ramaswamy Vijay , Gorender Ethel , Sakamoto Luis Henrique
Published: December 2020

BACKGROUND

Long-term survival in diffuse intrinsic pontine glioma is rare, and typically associated with atypical imaging and/or atypical clinical course. Although most patients harbor hotspot mutations in H3.1/3-K27M, a proportion of patients have alternate mutations, despite a typical clinicoradiological course. Herein we describe a long-term survivor with a classical presentation, treated with nimotuzumab, highlighting the challenges associated with such cases. CASE REPORT: A 5 year old male, diagnose in 2012 with a 10 day history multiple cranial neuropathies and a right hemiparesis. Cranial MRI revealed a poorly delimited diffuse pontine tumor and secondary hydrocephalus. Tumor biopsy was not performed due to the classic clinical presentation, and he received 54Gy/30 of radiation plus concomitant weekly nimotuzumab 150mg/m2. Initial tumor dimensions were 43x31x28mm. Nimotuzumab 150mg/m2 was continued every 2 weeks. Image assessment at week 12 of treatment revealed 16.9% volume increase, 4 weeks after radiotherapy completion. Nevertheless, subsequent neuroimaging at 24th, 36th, 60th, 96th and 108th weeks of nimotuzumab therapy showed a sustained and progressive tumor cytoreduction of 47.5%, 59%, 62.2%, 63.8% and 67%, respectively, when compared with post-radiotherapy dimensions. Currently, the patient is 13y old, good school performance, no neurologic disabilities. The last MRI at 394 weeks of nimotuzumab revealed dimensions of 21x19x14mm which corresponds to 70% of reduction compared with initial volume.

CONCLUSIONS

Our case of progressive cytoreduction over two years of a classic DIPG, diagnosed in the era prior to the discovery of the K27M mutation, highlights the challenges associated with long-term survival of this devastating entity.
DIPG-78. REVERTANCE OF THE H3K27M MUTATION RESCUES CHROMATIN MARKS NECESSARY FOR ONCOGENESIS IN DIFFUSE MIDLINE GLIOMA
Authors: Nesvick Cody , Day Charles , Zhang Liang , Hinchcliffe Edward , Daniels David
Published: December 2020

Diffuse midline glioma (DMG) is a lethal brain tumor that typically occurs in children. Numerous studies have demonstrated the central role of the H3K27M mutation and secondary loss of H3K27 trimethylation (H3K27me3) in DMG tumorigenesis. Understanding how the H3K27M mutation alters the epigenetic landscape of the cell is necessary for revealing molecular targets that are critical to tumorigenesis. To investigate the epigenetic effects of H3K27M mutation in DMG, we developed revertant DMG cell lines with the mutant methionine residue reverted to wildtype (i.e., M27K). Revertant cells were analyzed for epigenetic changes and phenotypic differences in vitro and in vivo. H3M27K DMG cells grew in culture but displayed diminished proliferative capacity. H3M27K cells demonstrated total loss of H3K27M expression and restored trimethylation of H3K27 and H3K4. Furthermore, consistent with the hypothesis that the H3K27M mutation impacts H3 phosphorylation via expression of Aurora Kinase during mitosis, H3M27K cells demonstrated reduced expression of both Aurora Kinase A and phosphorylation of H3 serine residues 10 and 28. In line with the critical role of H3S10 phosphorylation in chromatin segregation, H3M27K cells also demonstrated restored chromosome segregation compared to H3K27M cells. In vivo data will be discussed. Revertance of the H3K27M mutation reduces tumorigenesis in DMG tumors. Isogenic H3M27K cells display reversal of key epigenetic changes associated with oncogenesis in DMG. The revertant H3M27K DMG model is a useful tool to investigate the downstream epigenetic reprogramming specific to H3K27M mutation in these tumors.
DIPG-83. USING COPPER CHELATING AGENTS TO TARGET RECEPTOR TYROSINE KINASE SIGNALLING IN DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)
Authors: Michniewicz Filip , Saletta Federica , Rouen Jourdin , Ziegler David , Vittorio Orazio
Published: December 2020

DIPG is a universally fatal pediatric brain cancer. Receptor tyrosine kinase (RTK) pathway alterations are among the defining characteristics in many patients. Copper is a transition metal essential for cellular signaling, known to impact PI3K/AKT and MAPK/ERK pathways. Copper chelating agents are clinically approved for use in children with Wilson’s Disease, documented to reduce brain copper levels and are cited as potential cancer therapeutics. Due to copper’s wide cellular integration, we propose that targeting copper in DIPG through use of copper chelators is a viable therapeutic strategy and are strong candidates for combination therapy. Cytotoxicity assays performed in a panel of DIPG cell lines using copper chelator tetraethylenepentamine (TEPA) demonstrated a millimolar range of efficacy. To identify copper integrated pathways, western blots were performed on DIPG cell lines dosed with sub-lethal copper concentrations, which increased phosphorylated expression of AKT, ERK1/2, ERK5 and STAT3. Conversely, western blots performed after TEPA treatment demonstrated reduced phosphorylated expression of all these proteins compared to controls. Western blots investigating TEPA in combination with Everolimus and Trametinib demonstrated synergistic targeting of these proteins. Our results indicate that adding copper in the culture media initiated two RTK-mediated downstream signal transductions, including AKT and ERK and additionally STAT signaling. The use of copper chelator TEPA affected copper homeostasis and reduced DIPG cell proliferation. Our study proposes copper plays an important role in RTK-mediated signaling promoting DIPG proliferation. This implies that reducing copper with clinically available chelation agents can represent a potential anti-cancer treatment for DIPG.
EPCT-12. PNOC015: PHASE 1 STUDY OF MTX110 (AQUEOUS PANOBINOSTAT) DELIVERED BY CONVECTION ENHANCED DELIVERY (CED) IN CHILDREN WITH NEWLY DIAGNOSED DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG) PREVIOUSLY TREATED WITH RADIATION THERAPY
Authors: Mueller Sabine , Kline Cassie , Villanueva-Meyer Javier , Hoffman Carly , Raber Shannon , Bonner Erin , Nazarian Javad , Lundy Shannon , Molinaro Annette M , Prados Michael , Filbin Mariella , Gupta Nalin
Published: December 2020

OBJECTIVE

To determine safety and distribution of MTX110 delivered by CED in newly diagnosed DIPG patients.

METHODS

DIPG patients (3–21 years) were enrolled after radiation. CED of MTX110 combined with gadoteridol was completed based on dose levels (DL) (30–90 µM with volumes ranging from 3 cc (single dose) to 2 consecutive doses of 6 cc; total number of DL=7). Catheter position was chosen to maximize tumor coverage. Distribution of infusate was monitored with real-time MR imaging. Repeat CED was performed every 4–8 weeks if tolerated. Quality of life (QOL) assessments using PedsQL Generic Core and Brain Tumor modules were obtained at baseline (n=5), 3-months (n=3), and end of therapy (n=2). Single-cell RNA sequencing and analysis of histone modifications was performed to assess pharmacodynamic effects on DIPG cells.

RESULTS

Between May 2018-Dec 2019, 6 patients were enrolled (median age 8 years, range 5–21). Dose limiting toxicities included: grade 3 gait disturbance (DL7; cycle 1); grade 3 muscle weakness/vagus nerve disorder (DL5; cycle 4) and grade 2 intolerable dysphagia (DL7; cycle 4). Twelve CED procedures were completed at DL7 and repeated cycles ranged from 2 to 7. Infusion to distribution volume ratio was approximately 1:3.5. There were no significant changes in self-reported QOL. Parent ratings of patients’ worry (p = 0.04) and overall QOL (p = 0.03) significantly decreased at 3-months.

CONCLUSION

Repeat CED of MTX110 at the highest dose is tolerable. Tissue concentrations are likely to be substantially higher compared to oral dosing. Pharmacodynamic effects will be presented.
EPCT-13. CMV PP65 RNA-PULSED DENDRITIC CELL VACCINES FOR PEDIATRIC GLIOBLASTOMA AND MEDULLOBLASTOMA: PHASE I TRIAL RESULTS
Authors: Landi Daniel , Archer Gary , Driscoll Timothy , Lipp Eric , Archambault Bridget , Thompson Eric , Flahiff Charlene , Jaggers Denise , Hahn Kathleen , Healy Patrick , Ramirez Luis , Herndon James , Schroeder Kristin , Sampson John , Ashley David
Published: December 2020

BACKGROUND

Recurrent medulloblastoma and malignant glioma are lethal tumors that are virtually incurable. The cytomegalovirus (CMV) antigen pp65 is ubiquitously expressed on medulloblastoma and malignant glioma but not on healthy brain. We evaluated autologous CMV pp65 RNA-pulsed dendritic cell (DC) vaccines in children and young adults in a phase I trial.

METHODS

Circulating monocytes were harvested using leukapheresis, differentiated into DCs, matured, and pulsed with pp65 RNA using electroporation. DCs were packaged into vaccines (2x107DC/vaccine) and administered intradermally following tetanus-diphtheria toxoid site preconditioning every 2 weeks x3, then monthly. The primary objectives of the study were to establish the feasibility of generating at least 3 vaccines and safety. An exploratory objective was to evaluate the ability of vaccination to create and enhance patient pp65-specific T cell responses.

RESULTS

Eleven patients were enrolled with medulloblastoma (n=3) or glioblastoma (n=8). Ages ranged from 9–30 years old (mean 15.5y). Ten of 11 patients (91%) generated at least 3 vaccines (mean 6.2). Eight patients received at least 3 vaccines. To date, 4 patients have received all generated vaccines without progression, 4 patients have progressed, and 2 patients are still receiving vaccines. There have not been any severe adverse events probably or definitely related to vaccines. More mature data will be presented at ISPNO.

CONCLUSIONS

Leukapheresis and monocyte differentiation is a feasible strategy for generating adequate DCs for active immunization in children with malignant brain tumors. CMV pp65 RNA-pulsed DCs are well-tolerated and immunogenic. Efficacy endpoints will be evaluated in a subsequent phase II trial.
EPCT-17. A PHASE I AND SURGICAL STUDY OF RIBOCICLIB AND EVEROLIMUS IN CHILDREN WITH RECURRENT OR REFRACTORY MALIGNANT BRAIN TUMORS: PEDIATRIC BRAIN TUMOR CONSORTIUM INTERIM REPORT
Authors: DeWire Mariko , Fuller Christine , Campagne Olivia , Lin Tong , Pan Haitao , Young-Pussaint Tina , Baxter Patricia , Hwang Eugene , Bukowinski Andrew , Dorris Kathleen , Hoffman Lindsey , Waanders Angela , Karajannis Matthias , Steward Clinton , Onar-Thomas Arzu , Dunkel Ira , Fouladi Maryam
Published: December 2020

Genomic aberrations in the cell cycle and PI3K pathway are commonly observed in recurrent childhood brain tumors. Dual inhibition of CDK4/6 (ribociclib) and mTOR (everolimus) has strong biologic rationale, non-overlapping single-agent toxicities, and adult clinical experience. The maximum tolerated dosage (MTD) and/or recommended phase two dose (RP2D) of ribociclib and everolimus was determined in the Phase I study and ribociclib concentrations were characterized in plasma and tumor in children undergoing neurosurgical procedures. Following resection, eligible patients were enrolled in the Phase I study according to a rolling 6 design and received ribociclib and everolimus once daily for 21 days and 28 days, respectively. Patients undergoing surgery received ribociclib at the pediatric RP2D (350 mg/m2/day) for 7–10 days pre-operatively. Pharmacokinetic samples were collected on both cohorts and analyzed in nine patients on phase I study. Sixteen eligible patients enrolled on phase I study (median age 10.3 years; range: 3.9–20.4) and 5 patients were enrolled on the surgical cohort (median age 11.4 years; range: 7.2–17.1). Six patients enrolled at dose level 1 without dose limiting toxicities (DLT). Two of the three patients at dose level 2 experienced DLT (grade 3 hypertension and grade 4 ALT). The most common grade 3/4 toxicities were lymphopenia, neutropenia, and leucopenia. Everolimus concentrations following administration of everolimus alone were lower than those following drug combination, suggesting an impact of ribociclib on everolimus pharmacokinetics. The MTD/RP2D of ribociclib and everolimus in recurrent CNS tumors is 120 mg/m2 and 1.2 mg/ m2 daily for 21 days and 28 days, respectively.
EPEN-01. MULTIDISCIPLINARY TREATMENT IN EPENDYMOMA
Authors: Hirokawa Daisuke
Published: December 2020

BACKGROUND

In intracranial ependymoma, the effectiveness of chemotherapy and radiation therapy is unclear, and the degree of tumor removal contributes to the improvement of life prognosis.

METHODS

We examined ependymoma cases treated in our institution from July 1998 to March 2017.

RESULTS

There were 18 boys and 7 girls. The average age at the time of surgery is 5.3±3.6 years. The pathological diagnosis was Grade II for 8 cases and Grade III for 17 cases. Genetic analysis was performed in 16/25 cases (64%). Of the infratentorial cases, 10/11 cases (90.1%) were PFA and PFB were one case. Of the supratentorial cases, 3/5 cases (60%) were positive for RELA fusion. As chemotherapy, 19 patients were VCR + VP-16 + CDDP + CPA. Irradiation was performed in all cases, local irradiation (50.4–55.8Gy) in 22 cases (88%), and craniospinal irradiation in 2 cases (8%). The 7-year OS was 74.6±9% and the 7-year PFS was 59.7±10.5%. Grade III showed a short OS (p = 0.053). GTR and NTR were obtained in the first excision in 14 cases (56%), and OS and PFS were not significantly different from those in the STR group (p = 0.219, p = 0.248). GTR and NTR including 2nd-look surgery were obtained in 18 cases (72%), and significant improvement of OS was observed compared with STR group (p = 0.02).

CONCLUSION

Even if it is not GTR or NTR at the first operation, improvement of OS is expected by total excision after chemotherapy.
EPEN-17. FAVORABLE OUTCOME TO INTENSIVE CHEMOTHERAPY WITHOUT IRRADIATION IN INFANTILE METASTATIC EPENDYMOMA WITH A NOVEL MOLECULAR PROFILE: A CASE REPORT
Authors: de Faria Flavia W , Schieffer Kathleen M , Pierson Christopher , Boué Daniel , Zumberge Nicholas , Rusin Jerome , LaHaye Stephanie , Miller Katherine E , Koboldt Daniel C , Lichtenberg Tara , Leraas Kristen , Brennan Patrick , Kelly Benjamin , White Peter , Magrini Vincent , Wilson Richard K , Mardis Elaine R , Osorio Diana S , Leonard Jeffrey , Finlay Jonathan L
Published: December 2020

Metastatic disease at initial presentation of intracranial ependymoma is an uncommon occurrence with only rare reports of survival and is reportedly more prevalent in the youngest of children. Clinical and molecular characteristics associated with metastatic presentation, their prognostic implications, as well as optimal treatment options for such patients, have not been identified. CASE REPORT: A seven months old child presented with posterior fossa anaplastic ependymoma; following sub-total resection of primary tumor, a spine MRI revealed leptomeningeal dissemination along the cervical spinal cord and nerve roots of the cauda equina. The patient was successfully treated with five cycles of intensive induction chemotherapy (as per Head Start with high-dose methotrexate) followed by three sequential cycles of marrow-ablative chemotherapy and autologous hematopoietic progenitor cell rescue (AuHPCR) without irradiation; he is currently without evidence of the disease now 60 months following initial diagnosis. MOLECULAR/GENOMIC RESULTS: The patient was enrolled on a patient-centric comprehensive molecular profiling protocol, which included paired tumor-normal whole-exome sequencing, RNA sequencing of the disease-involved tissue, and DNA methylation classification. The genomic profile of the tumor was relatively unremarkable, revealing only a terminal gain of chromosome 3p and a terminal deletion of chromosome 22q, suggestive of an unbalanced translocation. Using RNA sequencing, we identified a novel SPECC1L-RAF1 gene fusion. The tumor harbors unique transcriptomic and DNA methylation profiles, failing to discretely classify with well-established ependymoma subgroups. CONCLUSION: Use of genomic profiling techniques provides meaningful information for disease characterization allowing for further expansion of the molecular spectrum associated with malignant disease.
EPEN-21. IMPAIRED NEURONAL-GLIAL FATE SPECIFICATION IN PEDIATRIC EPENDYMOMA REVEALED BY SINGLE-CELL RNA-SEQ
Authors: Englinger Bernhard , Gojo Johannes , Jiang Li , Hübner Jens M , Shaw McKenzie L , Hack Olivia A , Madlener Sibylle , Kirchhofer Dominik , Liu Ilon , Pyrdol Jason , Hovestadt Volker , Mazzola Emanuele , Mathewson Nathan D , Trissal Maria , Lötsch Daniela , Berger Walter , Dorfer Christian , Haberler Christine , Halfmann Angela , Mayr Lisa , Peyrl Andreas , Geyeregger Rene , Pajtler Kristian W , Milde Till , Geduldig Jack E , Pelton Kristine , Czech Thomas , Ashenberg Orr , Wucherpfennig Kai W , Rozenblatt-Rosen Orit , Alexandrescu Sanda , Ligon Keith L , Pfister Stefan M , Regev Aviv , Slavc Irene , Suva Mario L , Kool Marcel , Filbin Mariella
Published: December 2020

Ependymoma represents a heterogeneous disease affecting the entire neuraxis. Extensive molecular profiling efforts have identified molecular ependymoma subgroups based on DNA methylation. However, the intratumoral heterogeneity and developmental origins of these groups are only partially understood, and effective treatments are still lacking for about 50% of patients with high-risk tumors. We interrogated the cellular architecture of ependymoma using single cell/nucleus RNA-sequencing to analyze 24 tumor specimens across major molecular subgroups and anatomic locations. We additionally analyzed ten patient-derived ependymoma cell models and two patient-derived xenografts (PDXs). Interestingly, we identified an analogous cellular hierarchy across all ependymoma groups, originating from undifferentiated neural stem cell-like populations towards different degrees of impaired differentiation states comprising neuronal precursor-like, astro-glial-like, and ependymal-like tumor cells. While prognostically favorable ependymoma groups predominantly harbored differentiated cell populations, aggressive groups were enriched for undifferentiated subpopulations. Projection of transcriptomic signatures onto an independent bulk RNA-seq cohort stratified patient survival even within known molecular groups, thus refining the prognostic power of DNA methylation-based profiling. Furthermore, we identified novel potentially druggable targets including IGF- and FGF-signaling within poorly prognostic transcriptional programs. Ependymoma-derived cell models/PDXs widely recapitulated the transcriptional programs identified within fresh tumors and are leveraged to validate identified target genes in functional follow-up analyses. Taken together, our analyses reveal a developmental hierarchy and transcriptomic context underlying the biologically and clinically distinct behavior of ependymoma groups. The newly characterized cellular states and underlying regulatory networks could serve as basis for future therapeutic target identification and reveal biomarkers for clinical trials.
EPEN-24. SIOP EPENDYMOMA II: CENTRAL EPENDYMOMA MANAGEMENT ADVISORY GROUP – THE UK EXPERIENCE
Authors: Macarthur Donald C , Mallucci Conor , Kamaly-Asl Ian , Goodden John , Storer Lisa C D , Chapman Rebecca J , Kilday J-P , English Martin , Jaspan Tim , Chattopadhyay Arpita , Dineen Rob A , Avula Shivaram , Stivaros Stavros , Grundy Richard
Published: December 2020

Paediatric Ependymoma is the second most common malignant brain tumour of childhood with approximately 50% of cases recurring. It has been described as a “surgical” disease since patients who have undergone a gross total surgical resection (GTR) have a better prognosis than those who have a subtotal resection (STR). Analysis of the UKCCSG/SIOP 1992 04 clinical trial has shown that only 49% of cases had a GTR, with 5-year survival rates for STR of 22–47% and GTR of 67–80%. As part of the SIOP II Ependymoma trial the UK established a panel of experts in the treatment of Ependymoma from Neuro-oncology, Neuro-radiology and Neuro-surgery. Meeting weekly, cases are discussed to provide a consensus on radiological review, ensuring central pathological review, trial stratification and whether further surgery should be advocated on any particular case. Evaluation of the first 68 UK patients has shown a GTR in 47/68 (69%) of patients and STR in 21/68 (31%) of patients. Following discussion at EMAG it was felt that 9/21 (43%) STR patients could be offered early second look surgery. Following this 2nd look surgery the number of cases with a GTR increased to 56/68 (82%). There has been a clear increase in the number of patients for whom a GTR has been achieved following discussion at EMAG and prior to them moving forwards with their oncological treatment. This can only have beneficial effects in decreasing their risk of tumour recurrence or CSF dissemination and also in reducing the target volume for radiotherapy.
EPEN-25. EXCEPTIONAL CLINICAL AND IMAGING RESPONSE TO TRK-INHIBITION IN A PATIENT WITH SUPRATENTORIAL EPENDYMOMA HARBORING NTRK2 GENE FUSION
Authors: Mangum Ross , Reuther Jacquelyn , Adesina Adekunle , Kukreja Marcia , Curry Daniel , Malbari Fatema , Chintagumpala Murali , Muzny Donna M , Fisher Kevin , Roy Angshumoy , Bertrand Kelsey C , Mack Stephen C , Plon Sharon E , Parsons D Williams , Lin Frank Y
Published: December 2020

BACKGROUND

Patients with metastatic pediatric ependymoma have limited therapeutic options and poor outcomes. Approximately ¾ of supratentorial ependymomas are driven by C11ORF95-RELA fusions, and the remaining by a heterogeneous group of fusion events. We present a six year-old male diagnosed with supratentorial ependymoma with leptomeningeal carcinomatosis harboring an NTRK2-fusion. Local and distant multifocal, intracranial and intraspinal tumor recurrence occurred seven months following gross total resection of the primary lesion and proton beam craniospinal irradiation.

METHODS

DNA and RNA from FFPE tumor were used for targeted sequencing using an 81-gene fusion panel and 124-gene mutation panel. Separately, capture transcriptome sequencing, exome sequencing, and copy number array were performed as part of the Texas KidsCanSeq study, an NHGRI/NCI-funded Clinical Sequencing Evidence-Generating Research (CSER) consortium project. All sequencing was carried out in CLIA-certified laboratories.

RESULTS

An in-frame fusion between 5’ exons 1–3 of KANK1 and 3’ exons 16–21 of NTRK2, predicted to retain the kinase domain, was identified. At tumor recurrence, therapy was initiated with Larotrectinib, an FDA-approved pan-TRK inhibitor. Clinical improvement in cognitive speed, motor strength, and coordination was observed at two weeks with significant tumor response on MRI at two and four months.

CONCLUSION

TRK gene fusions have not previously been reported in ependymoma. Further tumor characterization by methylation profiling is underway and will be of diagnostic interest given the apparent discordance between tumor histology and molecular findings. This case highlights the potential impact of clinical genomic analysis for children with CNS tumors.
EPEN-31. SINGLE-CELL RNAseq OF CHILDHOOD EPENDYMOMA REVEALS DISTINCT NEOPLASTIC CELL SUBPOPULATIONS THAT IMPACT ETIOLOGY, MOLECULAR CLASSIFICATION AND OUTCOME
Authors: Donson Andrew , Gillen Austin , Kent Riemondy , Gilani Ahmed , Venkataraman Sujatha , Sanford Bridget , Griesinger Andrea , Amani Vladimir , Hankinson Todd , Handler Michael , Hesselberth Jay , Vibhakar Rajeev , Foreman Nicholas
Published: December 2020

Ependymoma (EPN) is a brain tumor commonly presenting in childhood that remains fatal in the majority of children. Intra-tumoral cellular heterogeneity in bulk-tumor samples significantly confounds our understanding of EPN biology, impeding development of effective therapy. We therefore used single-cell RNA sequencing to catalog cellular heterogeneity of 26 childhood EPN, predominantly from ST-RELA, PFA1 and PFA2 subgroups. ST-RELA and PFA subgroups clustered separately, with ST-RELA clustering largely according to individual sample-of-origin. PFA1 and PFA2 subgroup EPNs cells were intermixed and revealed 4 major subpopulations – 2 with characteristics of ependymal differentiation (transporter and ciliated phenotype subpopulations), an undifferentiated subpopulation and a mesenchymal phenotype. Pseudotime analysis showed the undifferentiated progenitor subpopulation either differentiating into ependymal differentiation subpopulations or transitioning into the mesenchymal subpopulation. Histological analysis revealed that undifferentiated and mesenchymal subpopulations cells colocalized to perinecrotic/perivascular zones, the putative ependymoma stem cell niche. Deconvolution of PFA bulk transcriptome data showed that undifferentiated and mesenchymal subpopulations were associated with a poor prognosis; whereas the ciliated ependymal cell-differentiated subpopulation was associated with a good prognosis. In conflict with current distinct classification paradigms, the ratio of mesenchymal and ciliated subpopulations determined bulk-tumor subgroups assignment to PFA1 and PFA2 respectively. This atlas of EPN cellular heterogeneity provides an important advance in our understanding of EPN biology, identifying high-risk associated subpopulations for therapeutic targeting.
EPEN-33. PHARMACOGENOMICS REVEALS SYNERGISTIC INHIBITION OF ERBB2 AND PI3K SIGNALING AS A THERAPEUTIC STRATEGY FOR EPENDYMOMA
Authors: Pauck David , Paisana Eunice , Cascão Rita , Sarikaya-Seiwert Sevgi , Marquardt Viktoria , Picard Daniel , Bartl Jasmin , Blümel Lena , Maue Mara , Dimitriadis Christian , Taban Kübra , Fischer Ute , Steiger Hans Jakob , Faria Cláudia , Reifenberger Guido , Borkhardt Arndt , Beez Thomas , Remke Marc
Published: December 2020

Subgroups of ependymoma, especially RELA fusion-positive and posterior fossa type A tumors, are associated with poor prognosis. Curative therapeutic strategies have not yet been identified. We set up a high-throughput drug screening (HTS) pipeline to evaluate clinically established compounds (n=196) in primary ependymoma cultures (n=12). As culturing ependymoma is challenging, assay miniaturization to 1536-well microplates emerged as a key feature to process HTS despite smallest cell numbers. DNA methylation profiling showed that entity and subgroup affiliation from primary diagnosis was maintained in primary cultures, as assessed through molecular neuropathology 2.0 based classification (MNP 2.0, Capper, D. et al., Nature, 2018). A comparison of HTS data of ependymoma and other pediatric brain tumor models (n=48) revealed a remarkable chemoresistance in vitro. However, we identified Neratinib, an irreversible ERBB2 inhibitor, as the most prominent candidate which was preferentially active in a subset of the investigated ependymoma cultures (n=5). Combinatory treatment with Copanlisib, a PI3K inhibitor, was able to overcome resistance to single agent treatment using Neratinib in established cell lines of ependymoma (n=3) and 2/4 primary cultures for which combinatory treatment could be tested. Finally, we validated efficacy of Neratinib combined with Copanlisib in mice bearing ependymoma xenografts which revealed significantly reduced tumor size compared to vehicle-treated animals. In summary, our study demonstrates that HTS may reveal targeted therapies for pediatric brain tumors. Specifically, we found a synergistic interaction of Neratinib and Copanlisib for treatment of ependymoma, thereby providing a novel therapeutic approach in an otherwise largely chemoresistant entity.
EPEN-35. PERITONEAL CARCINOMATOSIS OF ANAPLASTIC EPENDYMOMA: FIRST REPORTED CASE
Authors: Schwartz Jonathan , Weinmann Dena , Guerin Julia , Eckel Laurence , Gesina Keating , Daniels David
Published: December 2020

Peritoneal Carcinomatosis of anaplastic ependymoma is not a previously reported entity. The authors report on a child with multiple successfully treated brain and spine disease occurrences who subsequently develops carcinomatosis of the abdomen and no evidence of CNS recurrence. Ependymoma accounts for up to 10% of childhood CNS tumors diagnosed in the United States with a median age of 51–71 months. Typical locations are based on age. Disease is typically treated with surgical resection followed by radiation. The role of chemotherapy has not been proven but currently being examined with open clinical trials. We will describe patient’s presentations, clinical treatment and recurrence with subsequent treatment and outcome at time of meeting.
EPEN-49. RESPONSE OF RECURRENT EPENDYMOMA TO MEMMAT BASED METRONOMIC ANTIANGIOGENIC COMBINATION THERAPY UTILIZING TAPERED BEVACIZUMAB AND MAINTENANCE THERAPY WITH CELECOXIB AND FENOFIBRATE
Authors: Gillan Eileen
Published: December 2020

Recurrent ependymomas have a dismal prognosis (2 year survival rates 29% OS and 23% EFS) and are relatively resistant to conventional chemotherapy. We previously reported five relapsed ependymoma patients treated with a MEMMAT based metronomic antiangiogenic combination therapy. All patients are currently alive, including four patients who were multiply relapsed with at least three recurrences. These four patients received between 44–52 weeks of therapy with minimal toxicity. Three had recurrent disease within an average of 44 months (median 42 months) after discontinuation of therapy. One patient who received the following tapering bevacizumab schedule: q3 weeks x 3, q4 weeks x 4 and q5 weeks x 5 followed by maintenance therapy with fenofibrate and celecoxib is in complete remission 12 months post treatment. This regimen was well tolerated with good quality of life in this patient population. Our results suggest that the chosen anti-angiogenic drug combination prolonged the time to progression in these multiply relapsed patients and thus may be particularly beneficial for patients with recurrent ependymoma. Tapered bevacizumab and maintenance therapy with celecoxib and fenofibrate may be modifications worth further investigation for prolonged disease free survival in relapsed ependymoma patients.
EPEN-52. METABOLIC REGULATION OF THE EPIGENOME DRIVES LETHAL INFANTILE EPENDYMOMA
Authors: Kumar Sachin , Michealraj Antony , Kim Leo , Rich Jeremy , Taylor Michael
Published: December 2020

PFA ependymomas are a lethal glial malignancy of the hindbrain found in infants and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed to be a largely epigenetically driven entity, defined by hypomethylation at the histone 3 lysine 27 residue. Unfortunately, an almost complete lack of model systems has limited the discovery of novel PFA therapies. In this study, we have identified that the PFA hypoxic microenvironment controls the availability of specific metabolites, resulting in diminished H3K27 trimethylation and increased H3K27 acetylation in vitro and in vivo. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. Furthermore, perturbation of key metabolic pathways is sufficient to inhibit growth of PFA primary cultures in vitro. Although PFA tumors exhibit a low basal level of H3K27me3, inhibition of H3K27 methylation paradoxically demonstrates significant and specific activity against PFA. Thus, we propose a “Goldilocks Model” of metabolic-epigenetic regulation in PFA ependymoma, whereby increased or decreased H3K27 trimethylation results in cell death. Mapping of PFA ependymoma tumours suggests a cell of origin arising in the first trimester of human development where there is a known hypoxic microenvironment. Therefore, targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.