Pediatric Patients Research Articles

Safety of pediatric cardiac catheterisation procedures performed in rural India in a catheterisation lab setup for adult work

Introduction: The congenital heart disease (CHD) makes the largest group of congenital defects children are born with. The conservative estimate points towards 1% prevalence of CHD among the newborn. In India, each year approximately 2.4 lakh children are born with CHD, which is largest in the world. There are very centres offering paediatric cardiology services in India and they are unevenly distributed. Because of this, a lot of paediatric patients with CHD get treated at an adult cardiology facility, not always equipped with proper setup to handle complexities associated with paediatric cardiology work. The study aims to assess the safety and complications associated with paediatric cardiology catheterization-based procedures in a Cath lab is primarily used for adult cardiology work.Methods: The current study is a retrospective review of pediatric cardiac cath-lab-based procedures performed between April 2018 and March 2021.Results: During the study, 110 pediatric patients underwent 110 cath-lab-based procedures. A total of 20 procedures were performed as an emergency, and 90 were performed as planned procedures. Out of 110 procedures performed, 86.4% were completed without complications. Minor complications were observed in 9.1% of the procedure. Major complications were seen in 3 patients, and two patients died.Conclusion: The analysis shows that the complications associated with pediatric cardiac procedures performed on rural-based cath-lab oriented toward adult cardiology work are comparable to those of other large-volume pediatric cardiac centres.

Health‐Related Quality of Life Among Discharged Patients With Hemophagocytic Lymphohistiocytosis: A Follow‐Up Study

ABSTRACTPurposeEvaluating the post‐discharge health‐related quality of life (HRQoL) in hemophagocytic lymphohistiocytosis (HLH) and exploring its influencing factors.Patients and MethodsThe study was conducted at a regional pediatric medical center and involved pediatric patients diagnosed with HLH between July 2017 and July 2022. Healthy children of the same age and sex were included as the control group. The HRQoL and its associated factors in pediatric patients were assessed using the PedsQL 4.0 Parent Proxy Report and a general information survey.ResultsIn the first year following diagnosis, psychological health and overall score in HLH patients were worse than those of the control group. However, scores for emotional functioning, school functioning, physical health, psychosocial health, and overall scores in the HLH group increased over the years since diagnosis. By the 5‐year post diagnosis, there were no significant differences between the HLH group and the control group in social functioning, school functioning, physical health, psychosocial health, and overall scores (p > 0.05). Generalized linear model analysis revealed that HLH patients who underwent transplantation have worse social functioning, physical health, overall score, while HLH patients with HLH recurrence have worse social functioning, psychosocial health, overall score (p < 0.05).ConclusionThe HRQoL of HLH patients is compromised after discharge; however, it progressively returns to levels comparable to those of healthy cohorts over time since diagnosis. Transplantation, and HLH recurrence are identified as factors affecting the HRQoL in HLH patients.

NCOG-43. THE APPLICATION OF INDUCTION CHEMOTHERAPY COMBINED WITH RADIOTHERAPY IN YOUNG ADULTS WITH CNS GERM CELL TUMORS

Abstract BACKGROUND Central nervous system (CNS) germ cell tumors are rare brain neoplasms, accounting for approximately 0.3-0.5% of all CNS tumors. A combination of radiotherapy and chemotherapy is the standard of care (SOC) in pediatric patients. However, there is no SOC for young adult or adult patients. This study evaluates a regimen of induction chemotherapy followed by radiation in treating young adults with CNS germ cell tumors. METHOD Nine young adult patients diagnosed with pure CNS germinomas were identified in our institution. They underwent a treatment regimen of induction chemotherapies that were planned for four cycles and consisted of bleomycin (three doses per cycle), cisplatin (five doses per cycle) and etoposide (five doses per cycle) followed with whole brain and/or ventricular radiotherapy. The patients’ overall survival (OS), neurological function (including cognition), and adverse events (AE) were analyzed. RESULT Among the nine patients (seven males and two females), the median age is 20 years (range: 17-33 years). They received bleomycin, cisplatin and etoposide (median: two cycles, range: 1-4), and subsequent radiotherapy with plans based on tumor location by radiation oncologists, with a median radiotherapy dose of 45 Gy (range: 36-50.4). Seven patients had a complete response after chemotherapy. The median OS is 53 months (range: 39-121). There is no identifiable cognitive impairment by neurological exam. All patients experienced at least one, reversible, grade 3 AE of myelosuppression. All patients return to their normal baseline including employment. Results of neuropsychological evaluation and all AEs will be presented at the conference. CONCLUSION Induction chemotherapy followed by radiotherapy is potentially safe and effective with manageable and reversible side effects from chemotherapy without cognitive and functional impairment in the nine young adult patients with CNS germ cell tumors. A prospective study of this approach in a clinical trial setting is warranted.

Pharmacological management of pediatric metabolic dysfunction‐associated steatotic liver disease

AbstractPediatric obesity, characterized by a body mass index (BMI) at or above the 95th percentile for age, affects a substantial number of children and adolescents worldwide. Metabolic dysfunction‐associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease, represents a prominent hepatic manifestation of obesity and metabolic syndrome, emerging as the most prevalent hepatic disorder among pediatric patients and a significant contributor to liver transplantation in adults. The escalating prevalence of pediatric MASLD mirrors the alarming rise in childhood obesity rates over recent decades. While lifestyle modifications focusing on dietary changes and increased physical activity constitute the cornerstone of MASLD management, achieving and maintaining significant weight reduction remains challenging. Moreover, disease progression often persists despite standard‐of‐care interventions, warranting exploration into alternative therapeutic strategies. Pharmacological interventions, particularly, glucagon‐like peptide‐1 receptor agonists (GLP‐1RA), have shown promise in addressing pediatric obesity and its associated comorbidities, including MASLD. Recent studies have demonstrated the efficacy of GLP‐1RA in inducing weight loss and improving liver enzyme levels, suggesting a potential role in halting disease progression, and reducing the risk of major adverse liver outcomes. This review provides a comprehensive overview of the current pharmacotherapy landscape for pediatric MASLD, with a focus on novel agents such as GLP‐1RA. Furthermore, the manuscript proposes a practical algorithm to assist in integrating GLP‐1RA into the clinical management of pediatric patients with obesity and MASLD. Despite promising results, further research is warranted to elucidate the long‐term efficacy and safety of GLP‐1RA in pediatric populations.

Myocardial Strain Assessment for Early Duchenne Muscular Dystrophy Diagnosis in Pediatric Patients Using Cardiac MRI

Assessing myocardial strain remains challenging, particularly in the pediatric population, due to the smaller heart sizes, higher heart rates, and variability in strain parameters compared to adult populations. This study aimed to investigate the utility of myocardial strain measurements using cardiac magnetic resonance-feature tracking (CMR-FT) for early diagnosis of Duchenne muscular dystrophy (DMD) in pediatric patients. Twenty-eight DMD patients and 20 healthy controls were involved in this study. Global circumferential, longitudinal, and radial strain (GCS, GLS, and GRS) were measured for the left ventricle (LV) using CMR-FT. Segmental strain values only of the inferolateral and anterolateral LV segments in DMD patients without late gadolinium enhancement (LGE) and DMD patients with LGE were compared to the healthy controls. Strain measurements using CMR-FT in DMD patients were considerably lower than those of healthy controls, with all p-values lower than 0.001. DMD patients without LGE showed decreased inferolateral and anterolateral segmental values only relative to healthy controls. The same behavior was maintained for the LV geometry. Multivariable linear regression demonstrated that the end-systole (ES) wall thicknesses and thickening were associated with decreased GCS and GLS. CMR-FT is crucial in detecting cardiac abnormalities in patients with DMD. It represents an innovative imaging biomarker that can detect initial myocardial alterations in DMD cardiomyopathy without relying on gadolinium.

NCOG-07. SAFETY OF ONC201 TREATMENT IN PATIENTS WITH PREVIOUSLY TREATED H3 K27M-MUTANT GLIOMA: RESULTS FROM ONC028, AN ONGOING COMPASSIONATE USE PROGRAM

Abstract PURPOSE H3 K27M-mutant diffuse midline glioma (DMG) has a poor prognosis, with a median overall survival of 1 year and no proven treatments beyond radiotherapy. ONC201 (dordaviprone), a first-in-class imipridone, previously demonstrated durable responses in patients with recurrent H3 K27M-mutant DMG. The present analysis reports safety data from ONC028, a compassionate use program (CUP) for patients with previously treated H3 K27M-mutant glioma. METHODS ONC028 is an expanded access program that provides ONC201 monotherapy to patients with H3 K27M-mutant glioma. Eligible patients are adults or pediatric patients with H3 K27M-mutant glioma, prior therapy including at least radiation, and adequate organ function. Patients must be ineligible for enrollment in other ongoing clinical studies evaluating ONC201. ONC201 is administered orally once weekly at 625 mg or dose-equivalent based on body weight for pediatric patients. MRIs are performed every two 28-day cycles for the initial 12 months, thereafter every 2-3 cycles. Treatment continues until disease progression, unacceptable adverse events (AEs), or withdrawal of consent. Treatment may continue post-progression at the discretion of the treating physician. Bevacizumab use for radiation necrosis or symptom management is acceptable. AEs are assessed by NCI CTCAE v5.0 criteria. RESULTS The 422 enrolled patients include 191 adults (45.2%) and 231 children (54.7%); 87.1% had a performance score ≥60 and the most common tumor location was the pons (57.3%). Any-causality Grade ≥3 AEs have been reported in 200 patients (47.4%). Grade ≥3 treatment-related AEs (TR-AEs) were reported in 19 (4.5%) patients; the commonest was decreased lymphocyte count, occurring in 3 (0.7%) patients. Any-causality serious AEs (SAE) were reported in 43.1% (n=182) patients. There were 10 (2.4%) patients with reports of treatment-related SAEs, the commonest were ascites, nausea, vomiting, and seizure, each occurring in 2 patients (0.2%). CONCLUSIONS ONC028 provides expanded access to ONC201 treatment for patients with previously treated H3 K27M-mutant glioma who are ineligible for enrollment in ongoing trials of ONC201. ONC201 treatment remains well-tolerated.

EXTH-11. PEDIATRIC GLIOMA IMMUNE PROFILING IDENTIFIES TIM3 AS A THERAPEUTIC TARGET IN BRAF-FUSION PILOCYTIC ASTROCYTOMA

Abstract Despite being the leading cause of childhood mortality, pediatric gliomas have been relatively understudied. Repurposing of adult brain tumor immunotherapies in pediatric patients has not been successful, highlighting the need for pediatric-specific immunotherapies. Pilocytic astrocytomas (PA) are the most common pediatric glioma. While surgical resection of PA is the first-line treatment, the ten-year progression-free survival rate for patients with residual tumors is <50%. Notably, some PAs undergo spontaneous regression after partial resection, suggesting potential baseline tumor immunoreactivity. Whole transcriptome sequencing performed on a commercial platform of pediatric gliomas (n=250) showed that MAPK-driven gliomas have higher interferon signatures compared to other molecular subgroups. Single-cell sequencing identified a unique activated and cytotoxic microglia population designated MG-Act in BRAF-fused MAPK-activated PA (n=13; p < 0.05), but not in pediatric high-grade gliomas (n=5) or normal brain (n=3). TIM3 was expressed on the luminal side of endothelial cells and MG-Act, but not in the surrounding normal brain based on sequential multiplex imaging. Flow cytometry showed that TIM3 intensity is upregulated on immune cells in the PA tumor microenvironment (TME) relative to matched peripheral blood immune cells (n=6; p < 0.01). Anti-TIM3 reprogrammed fresh ex vivo immune cells from the TME of human PAs (n=3) to a pro-inflammatory cytotoxic phenotype. In a genetically engineered murine model of MAPK-driven low-grade gliomas, median survival (MS) was 252 days in mice treated with anti-TIM3 (n=21; p<0.01) relative to IgG control (MS: 110 days; n=20) or anti-PD-1 (MS: 134 days; n=20). The therapeutic activity of anti-TIM3 was abrogated in the CX3CR1 microglia knockout background. ScRNA sequencing data during the therapeutic window of anti-TIM3 in wild-type mice demonstrated enrichment of the MG-Act population within low-grade gliomas at two different longitudinal time points but not in IgG-treated controls. Together, these data indicate that anti-TIM3 should be considered for clinical trials in pediatric low-grade MAPK-driven gliomas.

Eltrombopag for Treatment of Thrombocytopenia After Autologous Stem Cell Transplantation in Children: Single Center Experience

Introduction: Thrombocytopenia is a common clinical problem in cancer patients undergoing high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HSCT). It can occur as prolonged isolated thrombocytopenia (PIT) or secondary failure of platelet recovery (SFPR) and may cause potentially fatal bleeding. However, data on the treatment of post-transplant thrombocytopenia is still lacking. Methods: We reported our practices involving 15 pediatric patients who received eltrombopag (ELT) treatment for PIT and SFPR after autologous HSCT. Results: The overall response was 78.5% (11/14), with 1 patient excluded due to noncompliance. The 12 surviving patients' median follow up was 699 days (range: 167 to 2250 d). Conclusions: Our study indicates the efficacy and safety of ELT for treating PIT and SFPR after autologous HSCT in pediatric patients. However, more studies are needed to confirm these findings in children.

NIMG-70. COMPARISON OF VOLUMETRIC AND CROSS-SECTIONAL MEASUREMENTS IN DIFFUSE MIDLINE GLIOMAS: RETHINKING RESPONSE ASSESSMENT

Abstract BACKGROUND The Response Assessment in Pediatric Neuro-Oncology (RAPNO) criteria, which are based on bidimensional or cross-sectional product (CP) measurements of tumor size, are the standard for assessing treatment response in diffuse midline glioma (DMG). This study aims to investigate the correlation between CP and volumetric measurements in progressive disease (PD) and compare their prognostic impact in pediatric patients with DMG. METHODS We retrospectively reviewed clinical and imaging data from 27 subjects with newly diagnosed DMG, encompassing 16 subjects from the PNOC003 and PNOC007 clinical trials and 11 subjects from the Children’s Hospital of Philadelphia. Tumors were segmented using a pretrained pediatric-specific autosegmentation model followed by manual revisions. Tumor volume and CP measurements were automatically derived from the outlined tumor. Cox regression analysis was used to compare the performance of CP and volumetric measurements in predicting overall survival (OS). The correlation between CP and volumetric thresholds for PD was assessed by linear regression. Comparison of survival of patients classified as PD versus non-PD by CP and volumetric measurements at 7 months post-baseline scan was performed using log-rank analysis. RESULTS Cox regression analysis demonstrated that volumetric measurements were significantly associated with OS (p=0.04), whereas CP measurements were not a significant predictor (p=0.07). An approximate 55% increase in segmented volume corresponded to a 25% increase in CP, which is the definition of PD according to RAPNO criteria (R2 = 0.71). At 7 months, volumetric classification of PD more accurately predicted survival than the CP method (p=0.06 for volumetric vs 0.14 for CP). CONCLUSION Our study showed that volumetric measurements are better predictors of survival compared to bidimensional measurements. We are extending this analysis to a larger sample size, examining survival at additional time points, and incorporating other factors influencing OS, such as treatment approaches.

NCMP-29. BRAIN LESIONS IN A TEEN WITH NEWLY DIAGNOSED T-CELL ALL AND SARS-COV-2 INFECTION

Abstract T-cell Lymphoblastic Leukemia (T-cell ALL) accounts for up to 15% of all newly diagnosed cases of acute lymphoblastic leukemia in pediatric patients (0-18 years old). Patients are at risk of opportunistic infections during induction therapy with up to 2% developing blood stream infections when their absolute neutrophil count is above 1,500. We report a case of a 15-year-old female with High-Risk T-cell ALL, CNS1 (negative CNS disease), presenting with three days of headaches, photophobia, and non-neutropenic fever. She completed induction chemotherapy one week earlier with vincristine, daunorubicin, calaspargase and a 28-day course of dexamethasone. On physical exam, she had no focal deficits or changes in sensation or strength. CBC was notable for a white blood cell count: 7500, hemoglobin: 8.6, platelets: 328,000 and ANC (Absolute Neutrophil Count): 4700. The patient was also COVID positive on admission. A contrast enhanced MRI brain demonstrated multiple diffusion restricting and peripherally enhancing lesions, concerning for intracranial abscesses. Neurosurgery performed a burr hole craniotomy and aspirated 5 mL of purulent drainage, the culture of which grew Aspergillus fumigatus complex. The patient was started empirically on Voriconazole, in addition to broad spectrum antibiotic coverage pending culture results, due to excellent CNS penetration and proven superiority to amphotericin-based therapy for invasive aspergillosis. Micafungin was added due to CT chest demonstrating nodular infiltrates, suggesting primary pulmonary aspergillosis with CNS dissemination. The patient improved symptomatically without further sequelae. Patients with COVID-19 on prolonged courses of corticosteroids are at higher risk of developing fungal co-infections regardless of neutrophil count. While pulmonary aspergillosis is the most common location of a COVID-19 aspergillus coinfection, there have been documented reports of intracranial micro-abscesses. Contrast-enhanced brain MRI should be obtained in any patient with a recent history of COVID-19 presenting with new neurological symptoms, especially in a patient with a recent history of corticosteroids.

CTNI-74. SONODYNAMIC THERAPY (SDT) USING INTRAVENOUS 5-AMINOLEVULINIC ACID WITH NON-ABLATIVE FOCUSED ULTRASOUND FOR THE TREATMENT OF DIFFUSE INTRINSIC PONTINE GLIOMAS IN PEDIATRICS: INITIAL SAFETY AND OUTCOMES THE MULTICENTER SDT-201 TRIAL

Abstract Diffuse intrinsic pontine glioma (DIPG) is the leading cause of mortality amongst pediatric neuro-oncologic diseases. Sonodynamic therapy with non-ablative MR-guided focused ultrasound (MRgFUS) is being investigated in multiple clinical trials. We describe safety outcomes and initial efficacy of SDT with 5-ALA for the treatment of pediatric patients with DIPG. Twelve patients with DIPG were treated from August 2022-April 2024 as part of a dose-escalation protocol with SDT in a multicenter Phase 1/2 clinical trial (NCT05123534). MRgFUS was combined with the prodrug SONALA-001 (5-ALA iv) to activate its metabolite, protoporphyrin IX, and thereby induce apoptosis within tumor cells. Treatment is delivered every 4 weeks for up to 12 treatments. Patient ages ranged from 3-23 years and 60% were male. Twelve patients underwent a total of 45 SDT treatments (range 2-9). When enrolled, median tumor volume was 1,337 cm3 (range, 310-2078 cm3) and duration since diagnosis was 5 months. SONALA-001 doses tested were 5 mg/kg and 10 mg/kg. Delivered ultrasonic acoustic energy ranged from 190-444 joules/cm3. After 6 months of median follow-up (range 2-18), 2 partial responses occurred, and 9 of 12 patients had stable or improved baseline symptoms (Lansky Status), including improved mobility and diplopia. One adverse clinical event included a small non-operative epidural hematoma secondary to a stereotactic frame pin. There have been no grade 3 or worse treatment-related adverse events or dose-limiting toxicities. Ten patients are alive a median of 11 months after diagnosis; 2 have deceased; 4 have discontinued treatment. Maximum percent tumor volume changes throughout treatment ranged from a -68% reduction to over 100% enlargement. Preliminary analysis of twelve pediatric patients treated with SDT for DIPG demonstrates acceptable safety outcomes and promising clinical results. Additional patient enrollment and longer follow-up times are required to determine efficacy.

INNV-18. FOCUS ON CURRENT AND EMERGING TREATMENT OPTIONS FOR GLIOMA: A COMPREHENSIVE REVIEW

Abstract This comprehensive review delves into the current updates and challenges associated with the management of low-grade gliomas (LGG), the predominant primary tumors in the central nervous system. With a general incidence rate of 5.81 per 100000, gliomas pose a significant global concern, necessitating advancements in treatment techniques to reduce mortality and morbidity. This review places a particular focus on immunotherapies, discussing promising agents such as Zotiraciclib and Lerapolturev. Zotiraciclib, a CDK9 inhibitor, has demonstrated efficacy in glioblastoma treatment in preclinical and clinical studies, showing its potential as a therapeutic breakthrough. Lerapolturev, a viral immunotherapy, induces inflammation in glioblastoma and displays positive outcomes in both adult and pediatric patients. Exploration of immunotherapy extends to Pembrolizumab, Nivolumab, and Entrectinib, revealing the challenges and variabilities in patient responses. Despite promising preclinical data, the monoclonal antibody Depatuxizumab has proven ineffective in glioblastoma treatment, emphasizing the critical need to understand resistance mechanisms. The review also covers the success of radiation therapy in pediatric LGG, with evolving techniques, such as proton therapy, showing potential improvements in patient quality of life. Surgical treatment is discussed in the context of achieving a balance between preserving the patient’s quality of life and attaining gross total resection, with the extent of surgical resection significantly influencing the survival outcomes. In addition to advancements in cancer vaccine development, this review highlights the evolving landscape of LGG treatment, emphasizing a shift toward personalized and targeted therapies. Ongoing research is essential for refining strategies and enhancing outcomes in the management of LGG.

Short Bowel Syndrome Is Not a Contraindication for Kidney Transplantation

ABSTRACTBackgroundShort bowel syndrome (SBS) is a malabsorptive condition that develops as a result of massive resection of the small intestine and causes morbidities such as chronic diarrhea, dehydration attacks, parenteral nutrition (PN) dependence, and recurrent infections. Kidney transplantation in this patient group may be complicated by aforementioned morbidities, as well as the absorption problems of immunosuppressive drugs.MethodsWe report the first pediatric patient (18‐month‐old male) with SBS secondary to volvulus who underwent a successful living related kidney transplantation with a primary diagnosis of autosomal recessive polycystic kidney disease and had a successful 4‐year follow‐up without intestinal transplantation.ResultsTacrolimus, mycophenolate mofetil (MMF), and prednisolone were administered for maintenance of immunosuppression after transplantation. The patient reached therapeutic trough levels of tacrolimus with usual doses. The 4‐year renal survival was excellent without a clinical evidence of rejection, despite long‐term necessity of PN and intravenous fluids.ConclusionsKidney transplantation should not be avoided in patients with SBS solely because of concerns about the effectiveness of immunosuppressive therapy. Prednisolone, tacrolimus, and MMF combination was effective in our case, and these drugs can be considered as first‐line agents in these patients.

Effects of obtaining plain radiographs in pediatric patients with radial head subluxation

Effects of obtaining plain radiographs in pediatric patients with radial head subluxation

SURG-40. PEDIATRIC LOWER GRADE GLIOMA SURGERY IN THE ERA OF GENOMIC MEDICINE

Abstract INTRODUCTION In the 2021 WHO Brain Tumor Classification, pediatric-type gliomas are distinctly categorized from their adult counterparts. The continual evolution of cancer genomics has significantly broadened the spectrum of available treatment options. Here we would like to consider surgery for pediatric low-grade gliomas. METHODS We retrospectively analyzed 41 cases of low-grade gliomas or glioneuronal tumors in pediatric patients who underwent surgery at our institute from 2002 to 2023. We discussed surgical strategies based on molecular classification. RESULTS Among the cases, there were 34 gliomas and 7 glioneuronal tumors. According to the new WHO classification, they corresponded to 1) Adult-type diffuse gliomas, 2) Pediatric-type diffuse low-grade gliomas, 3) Circumscribed astrocytic tumors, or 4) Glioneuronal and neuronal tumors. Cases without molecular diagnosis were also considered in light of the new WHO classification. Among molecularly diagnosed astrocytomas involving the cerebral hemisphere, brain stem, spinal cord, there were no cases of 1), and 2) 3) were the main cases. It is important in surgical selection to note that these cases generally have a more favorable prognosis compared to the adult type and have usefulness in diagnosing MAPK pathway abnormalities leading to the selection of molecularly targeted drugs. 3) includes pilocytic astrocytoma, subependymal giant cell astrocytoma, and pleomorphic xanthoastrocytoma. Among these, in the treatment of pilocytic astrocytoma of the visual tract and hypothalamus, biopsy is essential for molecular diagnosis and therapeutic agent selection. 4) is mainly an epilepsy-related tumor. While their removal contributes to genetic diagnosis and epileptic seizure control, total removal may not always be deemed necessary. CONCLUSION Based on the new WHO classification, a reevaluation of treatment strategies for pediatric brain tumors is necessary.

CNSC-68. SEX DIFFERENCES IN GLYCINE BIOSYNTHESIS DRIVE RESPONSES TO COMBINED NUTRIENT DEPRIVATION AND PHARMACOLOGICAL INHIBITION IN PEDIATRIC HGG

Abstract In children and adults, high-grade gliomas (HGGs) are the most common and deadly primary brain malignancies. Generally, male HGGs occur at higher incidence and demonstrate more rapid proliferation, resulting in shorter overall male survival. Obscurity of molecular mechanisms driving this phenomenon prevents implementation of clinically effective treatments. Recently, a positive correlation between HGG cellular proliferation and metabolic reprogramming toward glycine biosynthesis was identified. By analyzing pediatric and adult HGG patient data, we discovered significantly worse outcomes unique to pediatric males bearing upregulation of serine and glycine biosynthesis transcripts. Previously, we have identified differential flux of glucose into serine and glycine biosynthesis drives sex differences in lung cancer. Therefore, we sought to confirm and target this paradigm in our NF1-/- DNp53 model of HGG. By performing metabolic tracing with [13C]-labeled glucose in male and female cells, we identified higher enrichment of [13C]-labeled serine and glycine in male cells relative to female cells. Through Western blotting, we identify male-specific upregulation of serine and glycine biosynthetic pathway enzymes in transformed cells, supporting our labelling results. Next, we sought to determine if inhibition of de-novo serine and glycine biosynthesis was similarly sex-biased. Utilizing serine-and-glycine-deprived media conditions, we identified a male-biased decrease in proliferation following pharmacological inhibition of de-novo serine and glycine biosynthesis. More precisely, in the absence of exogenous glycine, we discovered that inhibition of de-novo synthesis of glycine from serine drove male-specific decreases in proliferation. Additionally, we identified that transformed female cell robustness against inhibition of glycine biosynthesis is driven by the uptake of exogenous nucleotide precursors. These data confirm that sex differences in de-novo glycine biosynthesis drive sex differences in HGG cellular proliferation. As well, our work suggests that dietary restriction of serine and glycine, in-combination with pharmacological inhibition of de-novo glycine biosynthesis, represents a novel treatment paradigm.

INNV-13. OPHTHALMOLOGICAL COMPLICATIONS IN NF-1 PATIENTS RECEIVING MEK INHIBITORS: MD ANDERSON CANCER CENTER EXPERIENCE

Abstract BACKGROUND MEK inhibitors (MEKi) are a novel therapy for plexiform neurofibromas and optic gliomas in Neurofibromatosis type 1 (NF1). Potential ophthalmic complications are MEKi-induced retinopathy (MEKAR) requiring regular ophthalmologic assessments. We assess the importance of screening and ocular adverse events (OAE) in pediatric NF1 patients receiving MEKi. METHODS We reviewed 45 NF1 patients with baseline and follow-up examinations before and post MEKi treatment initiation. Evaluations included comprehensive eye examination, visual acuity, dilated fundoscopic examination, optical coherence tomography (OCT) of the macula and nerve fiber layer, and Humphrey visual field testing. RESULTS Twenty-six (62% male) of 45 patients were included. Median age at treatment was 15 (range 2-23) years. Plexiform neurofibromas were the most common indication for MEKi (n=22). Selumetinib was the most common MEKi (n=19, 77%), then trametinib (n=6, 23%), and mirdametinib (n=1, 4%). Only two patients had to switch to different MEKi. Patients were followed for a mean of 413-days after treatment initiation (range 103-1122 days) for an average of 3.85 ophthalmology exams per patient. No retinopathy was observed at each of the 3–6 month follow-ups. Around 15% of patients experienced dry eye symptoms with none requiring artificial tears for management. Seven patients had pre-existing optic neuropathy. No dose adjustments were needed due to OAEs. One patient’s visual acuity decreased temporarily but returned to baseline and the patient remains on MEKi. CONCLUSIONS Regular ophthalmologic assessments are crucial for NF1 patients undergoing MEKi treatment. Consensus guidelines on frequency of ophthalmologic screening during MEKi treatment are not well reported. In our cohort no patients had MEKAR at regular 3–6 month follow ups. In addition to baseline screening, future larger cohort studies are needed to confirm if decreasing the frequency of retinal exams is safe while on MEKi to inform future clinical screening guidelines for NF1 patients on MEKi.

Exploring Sex-Based Neuropsychological Outcomes in Pediatric Brain Cancer Survivors: A Pilot Study

Background: The increasing survival rates among pediatric cancer patients underscore the critical need to understand the long-term psychosocial impacts of cancer treatments, such as cisplatin and carboplatin. While these treatments are lifesaving, they may pose risks to neurodevelopmental processes. Despite the substantial body of research highlighting cognitive impairments associated with cancer treatments, there remains a gap in understanding how these effects differ by sex. As sex differences could inform tailored interventions and support mechanisms for affected individuals, this pilot study aimed to examine the sex differences in neuropsychological outcomes in patients treated for brain cancer with cisplatin and/or carboplatin. Methods: Our study employed rigorous/structured neuropsychological assessments to evaluate executive functions in pediatric cancer survivors treated with cisplatin and/or carboplatin. We utilized the BRIEF and TOL tests to assess the key domains of executive function, including inhibitory control, cognitive flexibility, and problem-solving abilities. Additionally, psychosocial factors were evaluated using the Resiliency Scale to measure resilience and the PAT test to assess family psychosocial risk. Results: In our cohort of 17 patients, significant sex differences emerged, where males outperformed females in areas such as inhibitory control, impulse regulation, and strategic planning. Conclusions: These findings highlight the complexity of cognitive outcomes in pediatric cancer survivors. Understanding sex-specific differences is essential for developing tailored interventions that optimize cognitive and psychosocial outcomes. Future research should focus on larger cohorts and longitudinal studies to validate these findings and guide targeted interventions to improve survivorship outcomes.

DISP-03. HEALTH DISPARITIES IN NEURO-ONCOLOGY

Abstract Significant disparities in diagnosis, research, and treatment exist in neuro-oncology. Patients who identify as racial or ethnic minorities, sexual or gender minorities, elderly, rural, or have low socioeconomic status are more likely to have adverse outcomes. Using PubMed and expert opinion, we summarized the existing literature on health disparities in neuro-oncology. We categorized disparities based on primary central nervous system tumors (CNS), secondary CNS tumors, pediatric neuro-oncology, clinical trial enrollment and diversity, and financial toxicity. For patients with primary CNS tumors, we found that marginalized groups faced delays in diagnosis, lower rates of resection, and lower rates of postoperative radiation. For secondary CNS tumors, marginalized groups had lower rates of indicated cancer screening, less access to genetic testing, less access to advanced imaging, and lower rates of stereotactic radiosurgery and targeted therapies. Pediatric neuro-oncology patients had differences in morbidity and mortality based on socioeconomic status and race and faced substantial delays in diagnosis. Financial toxicity, the side effects of the high financial cost of a cancer diagnosis, disproportionately affects marginalized populations. This may be further exacerbated by the use of long-term medications such as IDH inhibitors. There is also unequal representation of diverse populations in neuro-oncology clinical trials. Compared to other cancer subspecialties, there is less available data on disparities, however, the types of disparities such as delays in diagnosis and outcomes are similar. Notably, there are not many interventions focused on mitigating these disparities. There needs to be additional research on health disparities in neuro-oncology, including both descriptions of existing disparities, but also on methods and interventions to address these disparities.

TMOD-11. ADVANCED MRI ANALYSIS TO ASSESS CHEMO-RADIATION RESPONSE IN PEDIATRIC EPENDYMOMA MODELS

Abstract Pediatric Ependymoma (EPN) is an aggressive brain tumor for which the benefits of chemo-radiation (CR) therapy have yet to be established. Our team has previously reported behavior patterns of EPN, including high tumor cellularity, cytological anaplasia, high mitotic index, tumor necrosis, and the presence of inflammatory cells such as M2-type macrophages. Recently, we have established advanced MRI protocols and computational algorithms for cell- and vessel-size imaging. The goal of this study is to develop advanced MRI analysis for CR response biomarkers (including tumor size, cell- and vessel-size correlates, and texture analysis) in mice with patient-derived xenografts (PDX) of pediatric EPN. Female severely immune deficient (SCID) mice were used for intracranial orthotopical inoculation of disaggregated tumors from pediatric EPN patients. All multi-parametric MRI sequences (fast spin echo, FLAIR, diffusion weighted, quantitative T2- and r2*-maps) were acquired on a Bruker 9.4 Tesla MRI scanner prior to CR, followed by 2 days and 2 weeks after CR treatment. All radiation treatment was performed using an animal image-guided precision XRAD irradiator (2Gyx5days), using MRI and CT guided EPN localization with added 30 mg/kg 5-fluoracil. All MRI analysis was performed using Bruker ParaVision software and MATLAB based modeling. The sensitivity of T2w-MRI scans was 0.2 mm for the smallest tumor detected; the median tumor volume at baseline was 2.5 mm3. Untreated mice showed rapid progression of tumor growth from small to intermediate to large EPN. The increased tumor sizes in untreated EPN were characterized by low ADC, highly elevated blood vessel density and large tumor cell size. A significant decrease in vessel size density and an increase in inflammatory cells were seen as soon as 2 days after CR therapy. The late response (2 weeks post CR) is characterized by increased ADC values and decreased cell size, resulting in significantly decreased tumor volumes.