CAR T cell therapy for pediatric central nervous system tumors: a review of the literature and current North American trials.

Central nervous system (CNS) tumors are the leading cause of cancer-related death in children. Typical therapy for CNS tumors in children involves a combination of surgery, radiation, and chemotherapy. While upfront therapy is effective for many high-grade tumors, therapy at the time of relapse remains limited. Furthermore, for diffuse intrinsic pontine glioma (DIPG) and diffuse midline glioma (DMG), there are currently no curative therapies. Chimeric antigen receptor T (CAR T) cell therapy is a promising novel treatment avenue for these tumors. Here, we review the preclinical evidence for CAR T cell use in pediatric brain tumors, the preliminary clinical experience of CNS CAR T cell trials, toxicity associated with systemic and locoregional CAR T cell therapy for CNS tumors, challenges in disease response evaluation with CAR T cell therapy, and the knowledge gained from correlative biologic studies from these trials in the pediatric and young adult population.

Detection of tumor-derived cell-free DNA in cerebrospinal fluid using a clinically validated targeted sequencing panel for pediatric brain tumors.

PURPOSE: Clinical sequencing of tumor DNA is necessary to render an integrated diagnosis and select therapy for children with primary central nervous system (CNS) tumors, but neurosurgical biopsy is not without risk. In this study, we describe cell-free DNA (cfDNA) in blood and cerebrospinal fluid (CSF) as sources for "liquid biopsy" in pediatric brain tumors. METHODS: CSF samples were collected by lumbar puncture, ventriculostomy, or surgery from pediatric patients with CNS tumors. Following extraction, CSF-derived cfDNA was sequenced using UW-OncoPlex™, a clinically validated next-generation sequencing platform. CSF-derived cfDNA results and paired plasma and tumor samples concordance was also evaluated. RESULTS: Seventeen CSF samples were obtained from 15 pediatric patients with primary CNS tumors. Tumor types included medulloblastoma (n = 7), atypical teratoid/rhabdoid tumor (n = 2), diffuse midline glioma with H3 K27 alteration (n = 4), pilocytic astrocytoma (n = 1), and pleomorphic xanthoastrocytoma (n = 1). CSF-derived cfDNA was detected in 9/17 (53%) of samples, and sufficient for sequencing in 8/10 (80%) of extracted samples. All somatic mutations and copy-number variants were also detected in matched tumor tissue, and tumor-derived cfDNA was absent in plasma samples and controls. Tumor-derived cfDNA alterations were detected in the absence of cytological evidence of malignant cells in as little as 200 µl of CSF. Several clinically relevant alterations, including a KIAA1549::BRAF fusion were detected. CONCLUSIONS: Clinically relevant genomic alterations are detectable using CSF-derived cfDNA across a range of pediatric brain tumors. Next-generation sequencing platforms are capable of producing a high yield of DNA alterations with 100% concordance rate with tissue analysis.

A Hemorrhagic Brain Mass in a Child With Encephalocraniocutaneous Lipomatosis.

Encephalocraniocutaneous lipomatosis (ECCL) is a rare genetic condition with well-described skin, ocular, and central nervous system findings. Several case reports have been documented demonstrating the presence of low-grade gliomas in patients with ECCL and the association with certain FGFR1 mutations. We report on a case of diffuse low-grade glioma, mitogen activated protein kinase pathway altered in a patient with ECCL, who was found to have a distinct FGFR1 mutation.

Impact of Time to Diagnosis on Morbidity and Survival in Children With Malignant Central Nervous System Tumors.

OBJECTIVE: The aim was to determine the impact of time to diagnosis (TTD) on morbidity and mortality and to identify factors associated with overall survival (OS) in pediatric patients with malignant central nervous system (CNS) tumors. METHODS: This is a retrospective review of all malignant CNS tumors presenting to 2 tertiary care pediatric hospitals from 2000 to 2019. Cox proportional hazard model analysis outcomes included TTD and OS as well as morbidity; stratified by tumor category, age, relapse, and presence of metastatic disease. RESULTS: There were 197 children with malignant CNS tumors (mean age 8.7 y, 61% male). Tumors included medulloblastoma (N=58, 29.4%), ependymoma (N=27, 13.7%), high-grade glioma (N=42, 21.3%), germ cell tumors (N=47, 23.9%), and other embryonal tumors (N=23, 11.7%). Median TTD from symptom onset was 62 (interquartile range: 26.5 to 237.5 d) and 28% had metastatic disease. Three-year progression free survival was 55% and 3-year OS was 73.1%. Increased OS was associated with increased TTD (parameter estimate 0.12; confidence interval [CI]: 0.019-7.06; P =0.019), high-grade glioma (hazard ratio [HR]: 2.46; CI [1.03-5.86]; P =0.042), other embryonal tumor (HR: 2.84; CI [1.06-7.56]; P =0.037), relapse (HR: 10.14; CI: 4.52-22.70; P <0.001) and metastatic disease (HR: 3.25; CI: 1.51-6.96; P =0.002). Vision change (HR: 0.58; CI: 0.313-1.06; P =0.078), hearing loss (HR: 0.71; CI: 0.35-1.42; P =0.355), and cognitive impairment (HR: 0.73; CI: 0.45-1.19; P =0.205) were not associated with TTD in this model. CONCLUSIONS: Increased median TTD is associated with higher OS in pediatric patients treated for malignant CNS tumors. Tumor biology and treatment modality are more important factors than TTD for predicting morbidity and long-term outcomes in pediatric patients with CNS tumors.

Outcomes of a radiation sparing approach in medulloblastoma by subgroup in young children: an institutional review.

OBJECTIVE: To describe disease outcomes including overall survival and relapse patterns by subgroup in young pediatric patients treated for medulloblastoma with a radiation-sparing approach. METHODS: Retrospective analysis of clinical outcomes includes treatment, relapse, and salvage therapy and late effects in children treated for medulloblastoma with a radiation-sparing approach at British Columbia Children's Hospital (BCCH) between 2000 and 2020. RESULTS: There were 30 patients (median age 2.8 years, 60% male) treated for medulloblastoma with a radiation-sparing approach at BCCH. Subgroups included Sonic Hedgehog (SHH) (n = 14), group 3 (n = 7), group 4 (n = 6), and indeterminate status (n = 3). Three- and 5-year event-free survival (EFS) were 49.0% (30.2-65.4%) and 42.0% (24.2-58.9%) and overall survival (OS) 66.0% (95% CI 46.0-80.1%) and 62.5% (95% CI 42.5 and 77.2%), respectively, with a median follow-up of 9.5 years. Relapse occurred in 12/25 patients following a complete response, of whom six (group 4: n = 4; group 3: n = 1; unknown: n = 1) were successfully salvaged with craniospinal axis (CSA) RT and remain alive at a median follow-up of 7 years. Disease/treatment-related morbidity included endocrinopathies (n = 8), hearing loss n = 16), and neurocognitive abnormalities (n = 9). CONCLUSIONS: This radiation sparing treatment approach for young patients with medulloblastoma resulted in a durable cure in most patients with SHH subgroup medulloblastoma. In those patients with groups 3 and 4 medulloblastoma, relapse rates were high; however, most group 4 patients were salvaged with RT.

Growth hormone after CNS tumor diagnosis: the fundamentals, fears, facts, and future directions.

Growth hormone deficiency (GHD) may occur in pediatric patients with central nervous system (CNS) tumors at initial tumor presentation or later as treatment-related sequelae. While it is well recognized that growth hormone (GH) has beneficial effects on growth and endocrinopathies, there's often hesitancy by clinicians to initiate GH therapy for GHD after CNS tumor diagnosis due to the perceived increased risk of tumor recurrence. The available data is described here and based on this review, there is no evidence of increased risk of tumor recurrence or secondary malignancy in patients treated with GH after CNS tumor diagnosis. Further understanding of tumor biology and presence of downstream GH targets including insulin-like growth factor-1 (IGF-1) and insulin receptor activity is still needed.

Complete resolution of alopecia totalis following chemotherapy for B-cell acute lymphoblastic leukemia.

Alopecia totalis (AT) is a cosmetically debilitating chronic disease characterized by non-scarring hair loss of the entire scalp. The clinical course of AT is highly unpredictable, and effective durable treatment options are limited. The resolution of alopecia has been reported post-autologous and allogeneic hematopoietic stem cell transplantation; however, no cases of AT remission following chemotherapy alone have been described. Herein, we present a case of complete remission of AT following chemotherapy for B-cell acute lymphoblastic leukemia in a pediatric patient.

Multi-institutional analysis of treatment modalities in basal ganglia and thalamic germinoma.

BACKGROUND: Central nervous system (CNS) germinomas are treatment-sensitive tumors with excellent survival outcomes. Current treatment strategies combine chemotherapy with radiotherapy (RT) in order to reduce the field and dose of RT. Germinomas originating in the basal ganglia/thalamus (BGTGs) have proven challenging to treat given their rarity and poorly defined imaging characteristics. Craniospinal (CSI), whole brain (WBI), whole ventricle (WVI), and focal RT have all been utilized; however, the best treatment strategy remains unclear. METHODS: Retrospective multi-institutional analysis has been conducted across 18 institutions in four countries. RESULTS: For 43 cases of nonmetastatic BGTGs, the 5- and 10-year event-free survivals (EFS) were 85.8% and 81.0%, respectively, while the 5- and 10-year overall survivals (OS) were 100% and 95.5%, respectively (one patient fatality from unrelated cause). Median RT doses were as follows: CSI: 2250 cGy/cGy(RBE) (1980-2400); WBI: 2340 cGy/cGy(RBE) (1800-3000); WVI: 2340 cGy/cGy(RBE) (1800-2550); focal: 3600 cGy (3060-5400). Thirty-eight patients (90.5%) received chemotherapy. There was no statistically significant difference in the EFS based on initial field extent (p = .84). Nevertheless, no relapses were reported in patients who received CSI or WBI. Chemotherapy alone had significantly inferior EFS compared to combined therapy (p = .0092), but patients were salvageable with RT. CONCLUSION: Patients with BGTGs have excellent outcomes and RT proved to be an integral component of the treatment plan. This group of patients should be included in future prospective clinical trials and the best RT field should be investigated further.

Association between in-line filtration and Type I hypersensitivity reactions in pediatric oncology patients receiving intravenous etoposide.

The objective of this study was to describe hypersensitivity reactions with and without the use of in-line filters during intravenous etoposide therapy in pediatric oncology patients. This was a retrospective review of all patients treated in the Division of Oncology/Hematology/Bone Marrow Transplant at British Columbia Children's Hospital with intravenous etoposide between December 1, 2013 and February 1, 2018. Hypersensitivity reactions and anaphylaxis associated with etoposide infusions were compared over time, including 12 months prior to, 27 months during the use of, and for 12 months after the discontinuation of in-line filtration. There were 192 patients (median age 6.0 (IQR 2.8-13.0) years treated with etoposide and 486 etoposide infusions including 137 (28%) before, 261 (54%) during and 88 (18%) after use of in-line filters at our center. Twenty-six of 486 (5%) and 13/486 (3%) of infusions resulted in a type I hypersensitivity reaction and anaphylaxis, respectively. There were 2/137 (1%), 36/261 (14%) and 1/88 (1%) infusion reactions prior to, during and after in-line filter use, respectively. Infusion reactions during the in-line filter period were higher than during the pre-filter (Z = 3.978; p < 0.001) and post-filter (Z = 3.335; p < 0.001) periods of the study. These data suggest that the use of in-line filtration may be associated with increased frequency of hypersensitivity reactions to etoposide in pediatric cancer patients.

Clinical Impact and Cost Efficacy of Newborn Screening for Congenital Adrenal Hyperplasia.

OBJECTIVES: To evaluate the clinical impact of a congenital adrenal hyperplasia (CAH) newborn screening program and incremental costs relative to benefits in screened vs unscreened infants. We hypothesized that screening would lead to clinical benefits and would be cost effective. STUDY DESIGN: This was an ambispective cohort study at British Columbia Children's Hospital, including infants diagnosed with CAH from 1988-2008 and 2010-2018. Data were collected retrospectively (unscreened cohort) and prospectively (screened cohort). Outcome measures included hospitalization, medical transport, and resuscitation requirements. The economic analysis was performed using a public payer perspective. RESULTS: Forty unscreened and 17 screened infants were diagnosed with CAH (47% vs 53% male). Median days to positive screen was 6 and age at diagnosis was 5 days (range, 0-30 days) and 6 days (range, 0-13 days) in unscreened and screened populations, respectively. In unscreened newborns, 55% required transport to a tertiary care hospital, 85% required hospitalization, and 35% required a fluid bolus compared with 29%, 29%, and 12% in screened infants, respectively. The cost of care was $33 770 per case in unscreened vs $17 726 in screened newborns. In the screened cohort, the incremental cost-effectiveness ratio was $290 in the best case analysis and $4786 in the base case analysis, per hospital day avoided. CONCLUSIONS: Compared with unscreened newborns, those screened for CAH were less likely to require medical transport and had shorter hospital stays. Screening led to a decrease in hospitalization costs. Although screening did not result in cost savings, it was assessed to be cost effective considering the clinical benefits and incremental cost-effectiveness ratio.

Ifosfamide, gemcitabine, and vinorelbine is an effective salvage regimen with excellent stem cell mobilization in relapsed or refractory pediatric Hodgkin lymphoma.

We describe 12 pediatric patients (8-16 years) with primary refractory (N = 6) or first relapse (N = 6) Hodgkin lymphoma (HL) treated with ifosfamide, gemcitabine, and vinorelbine (IGEV). The overall response rate to IGEV was 100%, with seven (58%) complete responses (CR) and five (42%) partial responses. Successful CD34+ stem cell mobilization was achieved in all patients. Following subsequent autologous stem cell transplantation, 10 patients (83%) achieved CR. At a median follow-up of 71 months, 11 patients had no evidence of disease. Five-year second event-free survival and overall survival were 83% ± 11.0% and 90.0% ± 9.5%, respectively. IGEV is an effective salvage regimen for children with relapsed/refractory HL.

The TLR9 agonist (GNKG168) induces a unique immune activation pattern in vivo in children with minimal residual disease positive acute leukemia: Results of the TACL T2009-008 phase I study.

Background: Preclinical studies show that TLR9 agonists can eradicate leukemia by induction of immune responses in vivo against AML and ALL. These studies demonstrated that TLR9 agonists induce an immediate NK response followed by adaptive T and B cells responses resulting in long term anti-leukemia immunity. Methods: The Therapeutic Advances in Childhood Leukemia and Lymphoma Phase I consortium performed a pilot study on 3 patients with MRD positive acute leukemia after an initial remission on conventional chemotherapy (TACL T2009-008) with the TLR 9 agonist (GNKG168). To guide future trial development, we evaluated the impact of GNKG168 by Nanostring on the expression 608 genes before and 8 days after initiation of GNKG168 therapy. Results: Twenty-three out of 578 markers on the nanostring panel showed significant difference (p ≤ 0.05). We focused on 8 markers that had the greatest differences with p < 0.01. Two genes were increased, promyelocytic leukemia protein (PML) and H-RAS, and 6 were decreased, Single Ig and TIR Domain containing (SIGIRR, IL1R8), interleukin 1 receptor 1 (IL1RL1, ST2), C-C Motif chemokine receptor 8 (CCR8), interleukin 7 R (IL7R), cluster of differentiation 8B (CD8B), and cluster of differentiation 3 (CD3D). Tumor inhibitory pathways were downregulated including the SIGIRR (IL1R8), important in IL-37 signaling and NK cell inhibition. TLR9 can induce IL-33, which is known to downregulate ST2 (IL1RL1) a receptor for IL-33. Conclusion: GNKG168 therapy is associated with immunologic changes in pediatric leukemia patients. Further work with a larger sample size is required to assess the impact of these changes on disease treatment and persistence of leukemia remission.

Adherence to a pediatric diabetic ketoacidosis protocol in children presenting to a tertiary care hospital.

OBJECTIVE: To review adherence to a provincial diabetic ketoacidosis (DKA) protocol and to assess factors associated with intravenous fluid administration and the length time on an insulin infusion. METHODS: A retrospective chart review was conducted of all DKA admissions to British Columbia Children's Hospital (BCCH) during September 2008 to December 2013. Data collection included diabetes history, estimation of dehydration, insulin and fluid infusion rates, and frequency of laboratory investigations. Markers of adherence included appropriate use of a fluid bolus, normal saline and insulin infusion time, fluid intake and outputs, and the frequency of blood work during the insulin infusion. A log-linear regression model was fitted to assess the factors associated with insulin infusion duration. RESULTS: Of 157 children (median [interquartile range] age: 10.6 years [5.0, 13.8]) hospitalized for DKA, 45% (n = 70) were male, 55% (n = 86) were transferred from other hospitals, and 26% (n = 40) were admitted to intensive care unit. Thirty-five percent of subjects estimated to have mild or moderate dehydration received fluid boluses. In the adjusted analysis, the average duration on DKA protocol was 39% (95% confidence interval [CI]: 12%, 67%) longer for children admitted with severe dehydration (compared to those with mild dehydration). CONCLUSIONS: Health care providers' adherence to the BCCH DKA protocol is poor. More severe dehydration at presentation is associated with longer duration of insulin infusion. Further knowledge translation initiatives focused on accurate estimation of volume depletion to ensure appropriate initial fluid resuscitation-as well as careful monitoring during DKA hospitalization-are important, especially in community centers.

Increased Risk of Obesity and Metabolic Dysregulation Following 12 Months of Second-Generation Antipsychotic Treatment in Children: A Prospective Cohort Study.

OBJECTIVE: To determine the risk of developing obesity and related metabolic complications in children following long-term treatment with risperidone or quetiapine. METHODS: This was a 1-year naturalistic longitudinal study conducted between February 2009 and March 2012. A total of 130 children aged 2 to 18 years without prior exposure to second-generation antipsychotics (SGAs) were enrolled at initiation of treatment with either risperidone or quetiapine. Metabolic parameters were measured at baseline and months 6 and 12. Data of 37 participants (20 treated with risperidone and 17 treated with quetiapine) who completed 12-month monitoring were used in the analysis. RESULTS: After 1 year of SGA treatment, mean weight increased significantly by 10.8 kg (95% CI 7.9 kg to 13.7 kg) for risperidone and 9.7 kg (95% CI 6.5 kg to 12.8 kg) for quetiapine. Body mass index z score also increased significantly in both groups (P < 0.001). There was a high incidence of children becoming overweight or obese (6/15 [40.0%] for risperidone-treated and 7/14 [50.0%] for quetiapine-treated). The mean levels of fasting glucose (for risperidone-treated) and ratio of total cholesterol to high-density lipoprotein cholesterol (for quetiapine-treated) increased significantly by 0.23 mmol/L (95% CI 0.03 mmol/L to 0.42 mmol/L) and 0.48 mmol/L (95% CI 0.15 mmol/L to 0.80 mmol/L), respectively. CONCLUSION: Children treated with risperidone or quetiapine are at a significant risk for developing obesity, elevated waist circumference, and dyslipidemia during 12 months of treatment. These data emphasize the importance of regular monitoring for early identification and treatment of metabolic side effects.

Cerebrospinal fluid liquid biopsy by low-pass whole genome sequencing for clinical disease monitoring in pediatric embryonal tumors.

Background: Liquid biopsy assays that detect cell-free DNA (cfDNA) in cerebrospinal fluid (CSF) are a promising tool for disease monitoring in pediatric patients with primary central nervous system (CNS) tumors. As a compliment to tissue-derived molecular analyses, CSF liquid biopsy has the potential to transform risk stratification, prognostication, and precision medicine approaches. Methods: In this pilot study, we evaluated a clinical pipeline to determine feasibility and sensitivity of low-pass whole genome sequencing (LP-WGS) of CSF-derived cfDNA from patients with CNS embryonal tumors. Thirty-two longitudinal CSF samples collected from 17 patients with molecularly characterized medulloblastoma (12), embryonal tumor with multilayered rosettes (2), CNS embryonal tumor, not elsewhere classified (NEC) (2), and atypical teratoid/rhabdoid tumor (1) were analyzed. Results: Adequate CSF-derived cfDNA for LP-WGS analysis was obtained in 94% of samples (30/32). Copy number variants compatible with neoplasia were detected in 90% (27/30) and included key alterations, such as isodicentric ch17, monosomy 6, and MYCN amplification, among others. Compared to tissue specimens, LP-WGS detected additional aberrations in CSF not previously identified in corresponding primary tumor specimens, suggesting a more comprehensive profile of tumor heterogeneity or evolution of cfDNA profiles over time. Among the 12 CSF samples obtained at initial staging, only 2 (17%) were cytologically positive, compared to 11 (92%) that were copy number positive by LP-WGS. Conclusions: LP-WGS of CSF-derived cfDNA is feasible using a clinical platform, with greater sensitivity for tumor detection compared to conventional CSF cytologic analysis at initial staging. Large prospective studies are needed to further evaluate LP-WGS as a predictive biomarker.

Somatic Versus Germline: A Case Series of Three Children With ATM-Mutated Medulloblastoma.

Somatic versus Germline-A Case Series of Three Children with ATM- mutated Medulloblastoma.

Locoregional CAR T Cells for the Treatment of CNS Tumors in Children: Investigational Drug Service Pharmacy Activities.

BACKGROUND: A major obstacle in translating the therapeutic potential of chimeric antigen receptor (CAR) T cells to children with central nervous system (CNS) tumors is the blood-brain barrier. To overcome this limitation, preclinical and clinical studies have supported the use of repeated, locoregional intracranial CAR T-cell delivery. However, there is limited literature available describing the process for the involvement of an investigational drug service (IDS) pharmacy, particularly in the setting of a children's hospital with outpatient dosing for CNS tumors. OBJECTIVES: To describe Seattle Children's Hospital's experience in clinically producing CAR T cells and the implementation of IDS pharmacy practices used to deliver more than 300 intracranial CAR T-cell doses to children, as well as to share how we refined the processing techniques from CAR T-cell generation to the thawing of fractionated doses for intracranial delivery. METHODS: Autologous CD4+ and CD8+ T cells were collected and transduced to express HER2, EGFR, or B7-H3-specific CAR T cells. Cryopreserved CAR T cells were thawed by the IDS pharmacy before intracranial delivery to patients with recurrent/refractory CNS tumors or with diffuse intrinsic pontine glioma/diffuse midline glioma. RESULTS: The use of a thaw-and-dilute procedure for cryopreserved individual CAR T-cell doses provides reliable viability and is more efficient than typical thaw-and-wash protocols. Cell viability with the thaw-and-dilute protocol was approximately 75% and was always within 10% of the viability assessed at cryopreservation. Cell viability was preserved through 6 hours after thawing, which exceeded the 1-hour time frame from thawing to infusion. CONCLUSION: As the field of adoptive immunotherapy grows and continues to bring hope to patients with fatal CNS malignancies, it is critical to focus on improving the preparatory steps for CAR T-cell delivery.