Nivolumab with or without ipilimumab in pediatric patients with high-grade CNS malignancies: Safety, efficacy, biomarker, and pharmacokinetics-CheckMate 908.

BACKGROUND: Therapeutic options are limited in pediatric CNS malignancies. CheckMate 908 (NCT03130959) is an open-label, sequential-arm, phase 1b/2 study investigating nivolumab (NIVO) and NIVO + ipilimumab (IPI) in pediatric patients with high-grade CNS malignancies. METHODS: Patients (N = 166) in 5 cohorts received NIVO 3 mg/kg every 2 weeks (Q2W) or NIVO 3 mg/kg + IPI 1 mg/kg every 3 weeks (4 doses) followed by NIVO 3 mg/kg Q2W. Primary endpoints included overall survival (OS; newly diagnosed diffuse intrinsic pontine glioma [DIPG]) and progression-free survival (PFS; other recurrent/progressive or relapsed/resistant CNS cohorts). Secondary endpoints included other efficacy metrics and safety. Exploratory endpoints included pharmacokinetics and biomarker analyses. RESULTS: As of January 13, 2021, median OS (80% CI) was 11.7 (10.3-16.5) and 10.8 (9.1-15.8) months with NIVO and NIVO + IPI, respectively, in newly diagnosed DIPG. Median PFS (80% CI) with NIVO and NIVO + IPI was 1.7 (1.4-2.7) and 1.3 (1.2-1.5) months, respectively, in recurrent/progressive high-grade glioma; 1.4 (1.2-1.4) and 2.8 (1.5-4.5) months in relapsed/resistant medulloblastoma; and 1.4 (1.4-2.6) and 4.6 (1.4-5.4) months in relapsed/resistant ependymoma. In patients with other recurrent/progressive CNS tumors, median PFS (95% CI) was 1.2 (1.1-1.3) and 1.6 (1.3-3.5) months, respectively. Grade 3/4 treatment-related adverse-event rates were 14.1% (NIVO) and 27.2% (NIVO + IPI). NIVO and IPI first-dose trough concentrations were lower in youngest and lowest-weight patients. Baseline tumor programmed death ligand 1 expression was not associated with survival. CONCLUSIONS: NIVO ± IPI did not demonstrate clinical benefit relative to historical data. The overall safety profiles were manageable with no new safety signals.

Accuracy of central neuro-imaging review of DIPG compared with histopathology in the International DIPG Registry.

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG) remains a clinico-radiologic diagnosis without routine tissue acquisition. Reliable imaging distinction between DIPG and other pontine tumors with potentially more favorable prognoses and treatment considerations is essential. METHODS: Cases submitted to the International DIPG registry (IDIPGR) with histopathologic and/or radiologic data were analyzed. Central imaging review was performed on diagnostic brain MRIs (if available) by two neuro-radiologists. Imaging features suggestive of alternative diagnoses included nonpontine origin, <50% pontine involvement, focally exophytic morphology, sharply defined margins, and/or marked diffusion restriction throughout. RESULTS: Among 286 patients with pathology from biopsy and/or autopsy, 23 (8%) had histologic diagnoses inconsistent with DIPG, most commonly nondiffuse low-grade gliomas and embryonal tumors. Among 569 patients with centrally-reviewed diagnostic MRIs, 40 (7%) were classified as non-DIPG, alternative diagnosis suspected. The combined analysis included 151 patients with both histopathology and centrally-reviewed MRI. Of 77 patients with imaging classified as characteristic of DIPG, 76 (99%) had histopathologic diagnoses consistent with DIPG (infiltrating grade II-IV gliomas). Of 57 patients classified as likely DIPG with some unusual imaging features, 55 (96%) had histopathologic diagnoses consistent with DIPG. Of 17 patients with imaging features suggestive of an alternative diagnosis, eight (47%) had histopathologic diagnoses inconsistent with DIPG (remaining patients were excluded due to nonpontine tumor origin). Association between central neuro-imaging review impression and histopathology was significant (p < 0.001), and central neuro-imaging impression was prognostic of overall survival. CONCLUSIONS: The accuracy and important role of central neuro-imaging review in confirming the diagnosis of DIPG is demonstrated.

Characteristics of patients ≥10 years of age with diffuse intrinsic pontine glioma: a report from the International DIPG/DMG Registry.

BACKGROUND: Diffuse intrinsic pontine gliomas (DIPG) generally occur in young school-age children, although can occur in adolescents and young adults. The purpose of this study was to describe clinical, radiological, pathologic, and molecular characteristics in patients ≥10 years of age with DIPG enrolled in the International DIPG Registry (IDIPGR). METHODS: Patients ≥10 years of age at diagnosis enrolled in the IDIPGR with imaging confirmed DIPG diagnosis were included. The primary outcome was overall survival (OS) categorized as long-term survivors (LTS) (≥24 months) or short-term survivors (STS) (<24 months). RESULTS: Among 1010 patients, 208 (21%) were ≥10 years of age at diagnosis; 152 were eligible with a median age of 12 years (range 10-26.8). Median OS was 13 (2-82) months. The 1-, 3-, and 5-year OS was 59.2%, 5.3%, and 3.3%, respectively. The 18/152 (11.8%) LTS were more likely to be older (P < .01) and present with longer symptom duration (P < .01). Biopsy and/or autopsy were performed in 50 (33%) patients; 77%, 61%, 33%, and 6% of patients tested had H3K27M (H3F3A or HIST1H3B), TP53, ATRX, and ACVR1 mutations/genome alterations, respectively. Two of 18 patients with IDH1 testing were IDH1-mutant and 1 was a LTS. The presence or absence of H3 alterations did not affect survival. CONCLUSION: Patients ≥10 years old with DIPG have a median survival of 13 months. LTS present with longer symptom duration and are likely to be older at presentation compared to STS. ATRX mutation rates were higher in this population than the general DIPG population.

Serial assessment of measurable residual disease in medulloblastoma liquid biopsies.

Nearly one-third of children with medulloblastoma, a malignant embryonal tumor of the cerebellum, succumb to their disease. Conventional response monitoring by imaging and cerebrospinal fluid (CSF) cytology remains challenging, and a marker for measurable residual disease (MRD) is lacking. Here, we show the clinical utility of CSF-derived cell-free DNA (cfDNA) as a biomarker of MRD in serial samples collected from children with medulloblastoma (123 patients, 476 samples) enrolled on a prospective trial. Using low-coverage whole-genome sequencing, tumor-associated copy-number variations in CSF-derived cfDNA are investigated as an MRD surrogate. MRD is detected at baseline in 85% and 54% of patients with metastatic and localized disease, respectively. The number of MRD-positive patients declines with therapy, yet those with persistent MRD have significantly higher risk of progression. Importantly, MRD detection precedes radiographic progression in half who relapse. Our findings advocate for the prospective assessment of CSF-derived liquid biopsies in future trials for medulloblastoma.

Proton therapy for adult medulloblastoma: Acute toxicity and disease control outcomes.

PURPOSE: We report disease control, survival outcomes, and treatment-related toxicity among adult medulloblastoma patients who received proton craniospinal irradiation (CSI) as part of multimodality therapy. METHODS: We reviewed 20 adults with medulloblastoma (≥ 22 years old) who received postoperative proton CSI ± chemotherapy between 2008 and 2020. Patient, disease, and treatment details and prospectively obtained patient-reported acute CSI toxicities were collected. Acute hematologic data were analyzed. RESULTS: Median age at diagnosis was 27 years; 45% of patients had high-risk disease; 75% received chemotherapy, most (65%) after CSI. Eight (40%) patients received concurrent vincristine with radiotherapy. Median CSI dose was 36GyE with a median tumor bed boost of 54GyE. Median duration of radiotherapy was 44 days. No acute ≥ grade 3 gastrointestinal or hematologic toxicities attributable to CSI occurred. Grade 2 nausea and vomiting affected 25% and 5% of patients, respectively, while 36% developed acute grade 2 hematologic toxicity (36% grade 2 leukopenia and 7% grade 2 neutropenia). Those receiving concurrent chemotherapy with CSI had a 38% rate of grade 2 hematologic toxicity compared to 33% among those not receiving concurrent chemotherapy. Among patients receiving adjuvant chemotherapy (n = 13), 100% completed ≥ 4 cycles and 85% completed all planned cycles. With a median follow-up of 3.1 years, 4-year actuarial local control, disease-free survival, and overall survival rates were 90%, 90%, and 95%, respectively. CONCLUSIONS: Proton CSI in adult medulloblastoma patients is very well tolerated and shows promising disease control and survival outcomes. These data support the standard use of proton CSI for adult medulloblastoma.

Relevance of Molecular Groups in Children with Newly Diagnosed Atypical Teratoid Rhabdoid Tumor: Results from Prospective St. Jude Multi-institutional Trials.

PURPOSE: Report relevance of molecular groups to clinicopathologic features, germline SMARCB1/SMARCA4 alterations (GLA), and survival of children with atypical teratoid rhabdoid tumor (ATRT) treated in two multi-institutional clinical trials. MATERIALS AND METHODS: Seventy-four participants with newly diagnosed ATRT were treated in two trials: infants (SJYC07: age < 3 years; n = 52) and children (SJMB03: age 3-21 years; n = 22), using surgery, conventional chemotherapy (infants), or dose-dense chemotherapy with autologous stem cell rescue (children), and age- and risk-adapted radiotherapy [focal (infants) and craniospinal (CSI; children)]. Molecular groups ATRT-MYC (MYC), ATRT-SHH (SHH), and ATRT-TYR (TYR) were determined from tumor DNA methylation profiles. RESULTS: Twenty-four participants (32%) were alive at time of analysis at a median follow-up of 8.4 years (range, 3.1-14.1 years). Methylation profiling classified 64 ATRTs as TYR (n = 21), SHH (n = 30), and MYC (n = 13), SHH group being associated with metastatic disease. Among infants, TYR group had the best overall survival (OS; P = 0.02). However, outcomes did not differ by molecular groups among infants with nonmetastatic (M0) disease. Children with M0 disease and <1.5 cm2 residual tumor had a 5-year progression-free survival (PFS) of 72.7 ± 12.7% and OS of 81.8 ± 11%. Infants with M0 disease had a 5-year PFS of 39.1 ± 11.5% and OS of 51.8 ± 12%. Those with metastases fared poorly [5-year OS 25 ± 12.5% (children) and 0% (infants)]. SMARCB1 GLAs were not associated with PFS. CONCLUSIONS: Among infants, those with ATRT-TYR had the best OS. ATRT-SHH was associated with metastases and consequently with inferior outcomes. Children with nonmetastatic ATRT benefit from postoperative CSI and adjuvant chemotherapy.

A phase II trial of selumetinib in children with recurrent optic pathway and hypothalamic low-grade glioma without NF1: a Pediatric Brain Tumor Consortium study.

BACKGROUND: Pediatric low-grade gliomas (pLGGs) are the most common childhood brain tumor. Progression-free survival (PFS) is much lower than overall survival, emphasizing the need for alternative treatments. Sporadic (without neurofibromatosis type 1) optic pathway and hypothalamic gliomas (OPHGs) are often multiply recurrent and cause significant visual deficits. Recently, there has been a prioritization of functional outcomes. METHODS: We present results from children with recurrent/progressive OPHGs treated on a PBTC (Pediatric Brain Tumor Consortium) phase II trial evaluating efficacy of selumetinib (AZD6244, ARRY-142886) a MEK-1/2 inhibitor. Stratum 4 of PBTC-029 included patients with sporadic recurrent/progressive OPHGs treated with selumetinib at the recommended phase II dose (25mg/m2/dose BID) for a maximum of 26 courses. RESULTS: Twenty-five eligible and evaluable patients were enrolled with a median of 4 (1-11) previous therapies. Six of 25 (24%) had partial response, 14/25 (56%) had stable disease, and 5 (20%) had progressive disease while on treatment. The median treatment courses were 26 (2-26); 14/25 patients completed all 26 courses. Two-year PFS was 78 ± 8.5%. Nineteen of 25 patients were evaluable for visual acuity which improved in 4/19 patients (21%), was stable in 13/19 (68%), and worsened in 2/19 (11%). Five of 19 patients (26%) had improved visual fields and 14/19 (74%) were stable. The most common toxicities were grade 1/2 CPK elevation, anemia, diarrhea, headache, nausea/emesis, fatigue, AST and ALT increase, hypoalbuminemia, and rash. CONCLUSIONS: Selumetinib was tolerable and led to responses and prolonged disease stability in children with recurrent/progressive OPHGs based upon radiographic response, PFS, and visual outcomes.

Clinical Outcomes and Patient-Matched Molecular Composition of Relapsed Medulloblastoma.

PURPOSE: We sought to investigate clinical outcomes of relapsed medulloblastoma and to compare molecular features between patient-matched diagnostic and relapsed tumors. METHODS: Children and infants enrolled on either SJMB03 (NCT00085202) or SJYC07 (NCT00602667) trials who experienced medulloblastoma relapse were analyzed for clinical outcomes, including anatomic and temporal patterns of relapse and postrelapse survival. A largely independent, paired molecular cohort was analyzed by DNA methylation array and next-generation sequencing. RESULTS: A total of 72 of 329 (22%) SJMB03 and 52 of 79 (66%) SJYC07 patients experienced relapse with significant representation of Group 3 and wingless tumors. Although most patients exhibited some distal disease (79%), 38% of patients with sonic hedgehog tumors experienced isolated local relapse. Time to relapse and postrelapse survival varied by molecular subgroup with longer latencies for patients with Group 4 tumors. Postrelapse radiation therapy among previously nonirradiated SJYC07 patients was associated with long-term survival. Reirradiation was only temporizing for SJMB03 patients. Among 127 patients with patient-matched tumor pairs, 9 (7%) experienced subsequent nonmedulloblastoma CNS malignancies. Subgroup (96%) and subtype (80%) stabilities were largely maintained among the remainder. Rare subgroup divergence was observed from Group 4 to Group 3 tumors, which is coincident with genetic alterations involving MYC, MYCN, and FBXW7. Subgroup-specific patterns of alteration were identified for driver genes and chromosome arms. CONCLUSION: Clinical behavior of relapsed medulloblastoma must be contextualized in terms of up-front therapies and molecular classifications. Group 4 tumors exhibit slower biological progression. Utility of radiation at relapse is dependent on patient age and prior treatments. Degree and patterns of molecular conservation at relapse vary by subgroup. Relapse tissue enables verification of molecular targets and identification of occult secondary malignancies.

A phase I trial of the CDK 4/6 inhibitor palbociclib in pediatric patients with progressive brain tumors: A Pediatric Brain Tumor Consortium study (PBTC-042).

BACKGROUND: Disruption of cell-cycle regulators is a potential therapeutic target for brain tumors in children and adolescents. The aim of this study was to determine the maximum tolerated dose (MTD) and describe toxicities related to palbociclib, a selective cyclin-dependent kinase 4/6 (CDK4/6) inhibitor in pediatric patients with progressive/refractory brain tumors with intact retinoblastoma protein. METHODS: Palbociclib was administered orally starting at 50 mg/m2 daily for the first 21 days of a 28-day course. Dose escalation was according to the Rolling-6 statistical design in less heavily (stratum I) and heavily pretreated (stratum II) patients, and MTD was determined separately for each group. Pharmacokinetic studies were performed during the first course, and pharmacodynamic studies were conducted to evaluate relationships between drug levels and toxicities. RESULTS: A total of 21 patients were enrolled on stratum I and 14 patients on stratum II. The MTD for both strata was 75 mg/m2 . Palbociclib absorption (mean Tmax between 4.9 and 6.6 h) and elimination (mean half-life between 11.3 and 19.5 h) were assessed. The most common toxicity was myelosuppression. Higher palbociclib exposure was associated with grade 3/4 neutropenia and leukopenia. Dose limiting toxicities included grade 4 neutropenia and grade 3 thrombocytopenia and dehydration. No patients had an objective response to palbociclib therapy. CONCLUSIONS: Palbociclib was safely administered to children and adolescents at a dosage of 75 mg/m2 for 21 consecutive days followed by seven days of rest in both strata. Future studies will establish its optimal utilization in pediatric patients with brain tumors.

Outcomes by Clinical and Molecular Features in Children With Medulloblastoma Treated With Risk-Adapted Therapy: Results of an International Phase III Trial (SJMB03).

PURPOSE: SJMB03 (ClinicalTrials.gov identifier: NCT00085202) was a phase III risk-adapted trial that aimed to determine the frequency and clinical significance of biological variants and genetic alterations in medulloblastoma. PATIENTS AND METHODS: Patients 3-21 years old were stratified into average-risk and high-risk treatment groups based on metastatic status and extent of resection. Medulloblastomas were molecularly classified into subgroups (Wingless [WNT], Sonic Hedgehog [SHH], group 3, and group 4) and subtypes based on DNA methylation profiles and overlaid with gene mutations from next-generation sequencing. Coprimary study end points were (1) to assess the relationship between ERBB2 protein expression in tumors and progression-free survival (PFS), and (2) to estimate the frequency of mutations associated with WNT and SHH tumors. Clinical and molecular risk factors were evaluated, and the most robust were used to model new risk-classification categories. RESULTS: Three hundred thirty eligible patients with medulloblastoma were enrolled. Five-year PFS was 83.2% (95% CI, 78.4 to 88.2) for average-risk patients (n = 227) and 58.7% (95% CI, 49.8 to 69.1) for high-risk patients (n = 103). No association was found between ERBB2 status and PFS in the overall cohort (P = .74) or when patients were stratified by clinical risk (P = .71). Mutations in CTNNB1 (96%), DDX3X (37%), and SMARCA4 (24%) were most common in WNT tumors and PTCH1 (38%), TP53 (21%), and DDX3X (19%) in SHH tumors. Methylome profiling classified 53 WNT (17.4%), 48 SHH (15.7%), 65 group 3 (21.3%), and 139 group 4 (45.6%) tumors. A comprehensive clinicomolecular risk factor analysis identified three low-risk groups (WNT, low-risk SHH, and low-risk combined groups 3 and 4) with excellent (5-year PFS > 90%) and two very high-risk groups (high-risk SHH and high-risk combined groups 3 and 4) with poor survival (5-year PFS < 60%). CONCLUSION: These results establish a new risk stratification for future medulloblastoma trials.

Pineoblastoma segregates into molecular sub-groups with distinct clinico-pathologic features: a Rare Brain Tumor Consortium registry study.

Pineoblastomas (PBs) are rare, aggressive pediatric brain tumors of the pineal gland with modest overall survival despite intensive therapy. We sought to define the clinical and molecular spectra of PB to inform new treatment approaches for this orphan cancer. Tumor, blood, and clinical data from 91 patients with PB or supratentorial primitive neuroectodermal tumor (sPNETs/CNS-PNETs), and 2 pineal parenchymal tumors of intermediate differentiation (PPTIDs) were collected from 29 centres in the Rare Brain Tumor Consortium. We used global DNA methylation profiling to define a core group of PB from 72/93 cases, which were delineated into five molecular sub-groups. Copy number, whole exome and targeted sequencing, and miRNA expression analyses were used to evaluate the clinico-pathologic significance of each sub-group. Tumors designated as group 1 and 2 almost exclusively exhibited deleterious homozygous loss-of-function alterations in miRNA biogenesis genes (DICER1, DROSHA, and DGCR8) in 62 and 100% of group 1 and 2 tumors, respectively. Recurrent alterations of the oncogenic MYC-miR-17/92-RB1 pathway were observed in the RB and MYC sub-group, respectively, characterized by RB1 loss with gain of miR-17/92, and recurrent gain or amplification of MYC. PB sub-groups exhibited distinct clinical features: group 1-3 arose in older children (median ages 5.2-14.0 years) and had intermediate to excellent survival (5-year OS of 68.0-100%), while Group RB and MYC PB patients were much younger (median age 1.3-1.4 years) with dismal survival (5-year OS 37.5% and 28.6%, respectively). We identified age < 3 years at diagnosis, metastatic disease, omission of upfront radiation, and chr 16q loss as significant negative prognostic factors across all PBs. Our findings demonstrate that PB exhibits substantial molecular heterogeneity with sub-group-associated clinical phenotypes and survival. In addition to revealing novel biology and therapeutics, molecular sub-grouping of PB can be exploited to reduce treatment intensity for patients with favorable biology tumors.

Correction to: Risk-adapted therapy and biological heterogeneity in pineoblastoma: integrated clinico-pathological analysis from the prospective, multi-center SJMB03 and SJYC07 trials.

The original version of this article unfortunately contained a typesetting error in Fig 3c. The corrected Fig. 3 is given in the following page.

Risk-adapted therapy and biological heterogeneity in pineoblastoma: integrated clinico-pathological analysis from the prospective, multi-center SJMB03 and SJYC07 trials.

Pineoblastoma is a rare embryonal tumor of childhood that is conventionally treated with high-dose craniospinal irradiation (CSI). Multi-dimensional molecular evaluation of pineoblastoma and associated intertumoral heterogeneity is lacking. Herein, we report outcomes and molecular features of children with pineoblastoma from two multi-center, risk-adapted trials (SJMB03 for patients ≥ 3 years; SJYC07 for patients < 3 years) complemented by a non-protocol institutional cohort. The clinical cohort consisted of 58 patients with histologically diagnosed pineoblastoma (SJMB03 = 30, SJYC07 = 12, non-protocol = 16, including 12 managed with SJMB03-like therapy). The SJMB03 protocol comprised risk-adapted CSI (average-risk = 23.4 Gy, high-risk = 36 Gy) with radiation boost to the primary site and adjuvant chemotherapy. The SJYC07 protocol consisted of induction chemotherapy, consolidation with focal radiation (intermediate-risk) or chemotherapy (high-risk), and metronomic maintenance therapy. The molecular cohort comprised 43 pineal parenchymal tumors profiled by DNA methylation array (n = 43), whole-exome sequencing (n = 26), and RNA-sequencing (n = 16). Respective 5-year progression-free survival rates for patients with average-risk or high-risk disease on SJMB03 or SJMB03-like therapy were 100% and 56.5 ± 10.3% (P = 0.007); respective 2-year progression-free survival rates for those with intermediate-risk or high-risk disease on SJYC07 were 14.3 ± 13.2% and 0% (P = 0.375). Of patients with average-risk disease treated with SJMB03/SJMB03-like therapy, 17/18 survived without progression. DNA-methylation analysis revealed four clinically relevant pineoblastoma subgroups: PB-A, PB-B, PB-B-like, and PB-FOXR2. Pineoblastoma subgroups differed in age at diagnosis, propensity for metastasis, cytogenetics, and clinical outcomes. Alterations in the miRNA-processing pathway genes DICER1, DROSHA, and DGCR8 were recurrent and mutually exclusive in PB-B and PB-B-like subgroups; PB-FOXR2 samples universally overexpressed the FOXR2 proto-oncogene. Our findings suggest superior outcome amongst older children with average-risk pineoblastoma treated with reduced-dose CSI. The identification of biologically and clinically distinct pineoblastoma subgroups warrants consideration of future molecularly-driven treatment protocols for this rare pediatric brain tumor entity.

Acute neurotoxicity following vincristine due to Charcot-Marie-Tooth disease in a young child with medulloblastoma.

Vincristine (VCR), a microtubule inhibitor that arrests the cell cycle by blocking metaphase of mitosis, is unique among the vinca alkaloids for causing polyneuropathy. Patients with increased risk of VCR neurotoxicity include the elderly and those with prior history of neuropathy-prone medical conditions. Identifying such risk factors prior to the development of neurotoxicity should be a goal prior to VCR administration. Clinicians should obtain a thorough medical and family history of neuropathies in any child scheduled to receive neurotoxic medications to avoid exacerbating an underlying disorder. We report a case of a young child with newly diagnosed medulloblastoma who started treatment on a VCR-containing chemotherapy regimen following surgery and craniospinal radiation. She subsequently developed severe peripheral polyneuropathy and new enhancement of the cranial and nerve roots following a relatively low cumulative dose of VCR and was diagnosed with previously unidentified Charcot-Marie-Tooth disease (CMTD) Type 1A. This case highlights that an evaluation of risk factors should be completed prior to initiation of neurotoxic chemotherapies and advocates for testing for inherited neuropathies such as CMTD even in asymptomatic patients when hereditary neuropathy is suspected.

Integrated analysis of long-term growth and bone development in pediatric and adolescent patients receiving bevacizumab.

BACKGROUND: We conducted an integrated analysis of clinical data to describe long-term effects of bevacizumab on growth and bone development in pediatric and adolescent patients with solid tumors. PROCEDURE: Clinical data were pooled from five phase I/II trials of bevacizumab versus chemotherapy: BERNIE, HERBY, and AVF4117s enrolled newly diagnosed patients, AVF3842s and AVF2771s enrolled patients with relapsed/refractory disease. Height, weight, body mass index (BMI), and bone-age data were pooled by treatment group. Growth charts were used to track and monitor growth in relation to a reference population of healthy children. Bone age was measured based on X-ray of the left hand and wrist. Analyses were exploratory/descriptive. RESULTS: Overall, 268 patients received bevacizumab ± chemotherapy and 135 received chemotherapy alone. Baseline characteristics were generally balanced. Median duration of long-term follow-up was 41.8 months (range, 2.4-75.1) with bevacizumab and 22.9 months (range, 2.8-69.2) with chemotherapy alone. Patients had age-appropriate baseline height and weight. Mean height and weight percentiles decreased over time in both treatment groups, but remained within the normal range (height: mean standard deviation score [SDS] range -2 to +3; weight: mean SDS range -2 to +1). Similar trends were seen in BMI. A tendency for reduced growth velocity relative to the reference population was observed at 6 months and 1 year in both groups, but there was no additional decrease for patients receiving bevacizumab. CONCLUSION: Bevacizumab did not appear to have additional negative effects on growth or development of pediatric and adolescent patients with solid tumors.

Heterogeneity within the PF-EPN-B ependymoma subgroup.

Posterior fossa ependymoma comprise three distinct molecular variants, termed PF-EPN-A (PFA), PF-EPN-B (PFB), and PF-EPN-SE (subependymoma). Clinically, they are very disparate and PFB tumors are currently being considered for a trial of radiation avoidance. However, to move forward, unraveling the heterogeneity within PFB would be highly desirable. To discern the molecular heterogeneity within PFB, we performed an integrated analysis consisting of DNA methylation profiling, copy-number profiling, gene expression profiling, and clinical correlation across a cohort of 212 primary posterior fossa PFB tumors. Unsupervised spectral clustering and t-SNE analysis of genome-wide methylation data revealed five distinct subtypes of PFB tumors, termed PFB1-5, with distinct demographics, copy-number alterations, and gene expression profiles. All PFB subtypes were distinct from PFA and posterior fossa subependymomas. Of the five subtypes, PFB4 and PFB5 are more discrete, consisting of younger and older patients, respectively, with a strong female-gender enrichment in PFB5 (age: p = 0.011, gender: p = 0.04). Broad copy-number aberrations were common; however, many events such as chromosome 2 loss, 5 gain, and 17 loss were enriched in specific subtypes and 1q gain was enriched in PFB1. Late relapses were common across all five subtypes, but deaths were uncommon and present in only two subtypes (PFB1 and PFB3). Unlike the case in PFA ependymoma, 1q gain was not a robust marker of poor progression-free survival; however, chromosome 13q loss may represent a novel marker for risk stratification across the spectrum of PFB subtypes. Similar to PFA ependymoma, there exists a significant intertumoral heterogeneity within PFB, with distinct molecular subtypes identified. Even when accounting for this heterogeneity, extent of resection remains the strongest predictor of poor outcome. However, this biological heterogeneity must be accounted for in future preclinical modeling and personalized therapies.

Regulatory T cell subsets in patients with medulloblastoma at diagnosis and during standard irradiation and chemotherapy (PBTC N-11).

BACKGROUND: We evaluated circulating levels of immunosuppressive regulatory T cells (Tregs) and other lymphocyte subsets in patients with newly diagnosed medulloblastoma (MBL) undergoing surgery compared to a control cohort of patients undergo craniectomy for correction of Chiari malformation (CM) and further determined the impact of standard irradiation and chemotherapy on this cell population. METHODS: Eligibility criteria for this biologic study included age 4-21 years, patients with CM undergoing craniectomy (as non-malignant surgical controls) and receiving dexamethasone for prevention of post-operative nausea, and those with newly diagnosed posterior fossa tumors (PFT) undergoing surgical resection and receiving dexamethasone as an anti-edema measure. Patients with confirmed MBL were also followed for longitudinal blood collection and analysis during radiotherapy and chemotherapy. RESULTS: A total of 54 subjects were enrolled on the study [22-CM, 18-MBL, and 14-PFT]. Absolute number and percentage Tregs (defined as CD4+CD25+FoxP3+CD127low/-) at baseline were decreased in MBL and PFT compared to CM [p = 0.0016 and 0.001, respectively). Patients with MBL and PFT had significantly reduced overall CD4+ T cell count (p = 0.0014 and 0.0054, respectively) compared to those with CM. Radiation and chemotherapy treatment in patients with MBL reduced overall lymphocyte counts; however, within the CD4+ T cell compartment, Tregs increased during treatment but gradually declined post therapy. CONCLUSIONS: Our results demonstrate that patients with MBL and PFT exhibit overall reduced CD4+ T cell counts at diagnosis but not an elevated proportion of Tregs. Standard treatment exacerbates lymphopenia in those with MBL while enriching for immunosuppressive Tregs over time.

Everolimus to treat aggressive retinal astrocytic hamartoma in tuberous sclerosis complex.

Retinal astrocytic hamartomas (RAH) are the most frequent ocular manifestation of tuberous sclerosis complex and are usually indolent, requiring only observation. We report an aggressive RAH subtype in a child unresponsive to anti-VEGF and laser therapy. Treatment with systemic everolimus was well-tolerated and significantly reduced ocular (and nonocular) tumor size and fluid exudation.