Targeting placental growth factor/neuropilin 1 pathway inhibits growth and spread of medulloblastoma.

Medulloblastoma is the most common pediatric malignant brain tumor. Although current therapies improve survival, these regimens are highly toxic and are associated with significant morbidity. Here, we report that placental growth factor (PlGF) is expressed in the majority of medulloblastomas, independent of their subtype. Moreover, high expression of PlGF receptor neuropilin 1 (Nrp1) correlates with poor overall survival in patients. We demonstrate that PlGF and Nrp1 are required for the growth and spread of medulloblastoma: PlGF/Nrp1 blockade results in direct antitumor effects in vivo, resulting in medulloblastoma regression, decreased metastasis, and increased mouse survival. We reveal that PlGF is produced in the cerebellar stroma via tumor-derived Sonic hedgehog (Shh) and show that PlGF acts through Nrp1-and not vascular endothelial growth factor receptor 1-to promote tumor cell survival. This critical tumor-stroma interaction-mediated by Shh, PlGF, and Nrp1 across medulloblastoma subtypes-supports the development of therapies targeting PlGF/Nrp1 pathway.

Daratumumab in Pediatric Relapsed/Refractory Acute Lymphoblastic Leukemia or Lymphoblastic Lymphoma: DELPHINUS Study.

Patients with relapsed/refractory acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) have poor outcomes compared with newly diagnosed, treatment-naïve patients. The phase 2, open-label DELPHINUS study evaluated daratumumab (16 mg/kg intravenously) plus backbone chemotherapy in children with relapsed/refractory B-cell ALL (n=7) after ≥2 relapses and children and young adults with T-cell ALL (children, n=24; young adults, n=5) or LL (n=10) after first relapse. The primary endpoint was complete response (CR) in the B-cell ALL (end of Cycle 2) and T-cell ALL (end of Cycle 1) cohorts, after which patients could proceed off study to allogeneic hematopoietic stem cell transplant (HSCT). Seven patients with advanced B-cell ALL received daratumumab with no CRs achieved; this cohort was closed due to futility. For the childhood T-cell ALL, young adult T-cell ALL, and T-cell LL cohorts, the CR (end of Cycle 1) rates were 41.7%, 60.0%, and 30.0%, respectively; overall response rates (any time point) were 83.3% (CR+CR with incomplete count recovery [CRi]), 80.0% (CR+CRi), and 50.0% (CR+partial response); minimal residual disease-negativity (<0.01%) rates were 45.8%, 20.0%, and 50.0%; observed 24-month event-free survival rates were 36.1%, 20.0%, and 20.0%; observed 24-month overall survival rates were 41.3%, 25.0%, and 20.0%; and allogeneic HSCT rates were 75.0%, 60.0%, and 30.0%. No new safety concerns with daratumumab were observed. In conclusion, daratumumab was safely combined with backbone chemotherapy in children and young adults with T-cell ALL/LL and contributed to successful bridging to HSCT. This trial was registered at www.ClinicalTrials.gov as NCT03384654.

Inotuzumab ozogamicin combined with chemotherapy in pediatric B-cell precursor CD22+ acute lymphoblastic leukemia: results of the phase IB ITCC-059 trial.

Inotuzumab ozogamicin (InO) is a CD22-directed antibody conjugated with calicheamicin. The phase IB of the ITCC-059 trial tested InO combined with chemotherapy in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Relapsed /refractory CD22+ BCP-ALL pediatric patients were enrolled. The primary objective was to establish the recommended phase II dose (RP2D). Secondary objectives included preliminary efficacy and tolerability. InO was combined with 1.5 mg/m2 of vincristine (days 3, 10, 17, 24), 20 mg/m2 of dexamethasone (2 5-day blocks, then amended), and intrathecal therapy. A rolling-6 design was used testing InO from 0.8 to 1.8 mg/m2/cycle. Between May 2020 and April 2022, 30 patients were treated, and 29 were evaluable for dose limiting toxicities (DLT). At 1.1 mg/m2/cycle, two of four patients had DLT (liver toxicity). InO was de-escalated to 0.8 mg/m2/cycle (N=6) without DLT while awaiting a protocol amendment to reduce dexamethasone dose to 10 mg/m2. Post amendment, InO was re-escalated to 1.1 mg/m2/cycle (N=6, 1 DLT), then to 1.4 mg/m2/ cycle (N=3, no DLT), and finally to 1.8 mg/m2/cycle (N=7, 1 DLT). Three additional patients were treated in an expansion cohort. The pooled response rate was 80% (24/30; 95% confidence interval [CI]: 61.4-92.3) and, among responders, 66.7% achieved minimal residual disease negativity. The RP2D of InO combined with vincristine, dexamethasone and intrathecal therapy was declared at 1.8 mg/m2/cycle (1.5 mg/m2/cycle after remission) in a fractioned schedule. This combination showed a response rate similar to the single agent cohorts of this trial, with liver toxicity issues at the initial higher dexamethasone dose (clinicaltrials gov. Identifier: NTR5736).

Osteosarcoma as a secondary malignancy following rhabdomyosarcoma: A report of 28 affected patients from the Cooperative Osteosarcoma Study Group (COSS).

BACKGROUND: Osteosarcoma may arise as a secondary malignancy following rhabdomyosarcoma (RMS). We utilized the Cooperative Osteosarcoma Study Group (COSS) database to better understand this association. PATIENTS AND METHODS: The COSS database (1980-05/2023) was searched for patients whose osteosarcoma was preceded by RMS. Eligible patients were analyzed for patient-, tumor-, and treatment-related variables as well as outcomes. RESULTS: The search revealed 28 eligible osteosarcomas (27 high-grade central, one periosteal; male:female = 16:12; median age RMS 2.1 [range: 0.9-10.0] years, osteosarcoma 13.5 [7.2-29.0] years). Genetic tumor-predisposition syndromes were documented in 12 patients. One patient had had a distinct malignancy prior to RMS, two intermittently, seven following osteosarcoma. Local RMS treatment had included radiotherapy in 20/26 cases (two unknown). Secondary osteosarcoma sites were extremity 13, trunk seven, head and neck eight; 15 osteosarcomas were radiation-associated. There was only one case of primary osteosarcoma metastases. Osteosarcoma treatment included chemotherapy (27), surgery (26), or radiotherapy (2). A macroscopically complete remission of all osteosarcoma sites was achieved in 24 cases. Median follow-up was 5.8 (range: 0.5-18.4) years after osteosarcoma and 8.1 (1.0-15.4) years for 14 survivors. Actuarial 5-year overall and event-free survival were 66% (standard error 9%) and 45% (10%), respectively. Five of 14 deaths were caused by further malignancies. CONCLUSION: This series offers a benchmark for patients who develop a secondary osteosarcoma after RMS. Affected patients are generally still in the pediatric age. The results obtained strongly argue for genetic predisposition testing in RMS and against therapeutic leniency in comparable situations.

Stopping antibacterial prophylaxis in pediatric allogeneic hematopoietic cell transplantation: An internal audit.

BACKGROUND: Antibacterial prophylaxis in children and adolescents undergoing allogeneic hematopoietic cell transplantation (HCT) is controversial and not recommended by international guidelines. We analyzed relevant posttransplant outcomes following discontinuation of antibacterial prophylaxis at a major European pediatric transplant center. METHODS: The single-center retrospective audit included all pediatric allogeneic HCT patients (pts) transplanted between 2011 and 2020 before (≤2014) and after (≥2015) stopping routine antibacterial prophylaxis with penicillin, metronidazole, and ciprofloxacin upon start of the conditioning regimen. The primary endpoint was overall survival until the first hospital discharge. Secondary endpoints included the occurrence of fever; bacterial infections; and cumulative days with antibacterial agents until discharge. RESULTS: A total of 257 HCT procedures were performed in 249 pts (median age: 10 years, range, 0.2-22.5) for leukemia/lymphoma (n = 150) and nonmalignant disorders (n = 107). Of these, 104 procedures were performed before (cohort 1) and 153 after (cohort 2) stopping prophylaxis. Overall survival until discharge was 90.4% in cohort 1 and 96.1% in cohort 2 (p = .06). No differences were observed in the occurrence of fever (92.3 vs. 94.1%; p = .57) and bacterial infections (34.6 vs. 25.5%; p = .11). The median number of days on antibacterial agents was significantly lower in cohort 2 (39 vs. 34; p = .002). Detection rates of resistant organisms were overall low. CONCLUSION: In this single-center audit, the stop of routine antibacterial prophylaxis had no effect on the occurrence of fever, bacterial infections, resistant organisms, and GVHD. Overall antibiotic use was significantly reduced, and survival was noninferior to the historical control cohort.

A phase 1 study of inotuzumab ozogamicin in pediatric relapsed/refractory acute lymphoblastic leukemia (ITCC-059 study).

This phase 1 study investigated the recommended phase 2 dose (RP2D) of inotuzumab ozogamicin (InO), a CD22-directed antibody-drug conjugate, in pediatric patients with multiple relapsed/refractory (R/R) CD22+ acute lymphoblastic leukemia (ALL). Patients (age ≥1 year or <18 years) received 3 doses of InO (days 1, 8, and 15) per course. Dose escalation was based on dose-limiting toxicities (DLTs) during course 1. Dose level 1 (DL1) was 1.4 mg/m2 (0.6, 0.4, 0.4 mg/m2) and DL2 was 1.8 mg/m2 (0.8, 0.5, 0.5 mg/m2). Secondary end points included safety, antileukemic activity, and pharmacokinetics. Twenty-five patients (23 evaluable for DLTs) were enrolled. In course 1, the first cohort had 1 of 6 (DL1) and 2 of 5 (DL2) patients who experienced DLTs; subsequent review considered DL2 DLTs to be non-dose-limiting. Dose was de-escalated to DL1 while awaiting protocol amendment to re-evaluate DL2 in a second cohort, in which 0 of 6 (DL1) and 1 of 6 (DL2) patients had a DLT. Twenty-three patients experienced grade 3 to 4 adverse events; hepatic sinusoidal obstruction syndrome was reported in 2 patients after subsequent chemotherapy. Overall response rate after course 1 was 80% (95% confidence interval [CI], 59% to 93%) (20 of 25 patients; DL1: 75% [95% CI, 43% to 95%], DL2: 85% [95% CI, 55% to 98%]). Of the responders, 84% (95% CI, 60% to 97%) achieved minimal residual disease (MRD)-negative complete response, and 12-month overall survival was 40% (95% CI, 25% to 66%). Nine patients received hematopoietic stem cell transplantation or chimeric antigen receptor T cells after InO. InO median maximum concentrations were comparable to simulated adult concentrations. InO was well tolerated, demonstrating antileukemic activity in heavily pretreated children with CD22+ R/R ALL. RP2D was established as 1.8 mg/m2 per course, as in adults. This trial was registered at https://www.clinicaltrialsregister.eu as EUDRA-CT 2016-000227-71.

Parvovirus B19 infection in pediatric allogeneic hematopoietic cell transplantation - Single-center experience and review.

BACKGROUND: Parvovirus B19 (B19V) infection following pediatric hematopoietic cell transplantation (HCT) is a rare complication and available data is scarce. Therefore, we present the experience with B19V Infection in allogeneic pediatric HCT recipients at our transplant center together with a systematic review of the literature. METHODS: Pediatric HCT patients with Parvovirus B19 infection treated at the University Children's Hospital Münster between 1999 and 2021 were retrospectively identified and clinical data were analyzed. Additionally, a systematic MEDLINE search to identify relevant articles was performed. RESULTS: We identified three out of 445 patients (0.6%) with B19V infection post-transplantation. B19V infection occurred in combination with other complications like Graft-versus-Host disease, additional infections, or autoimmune-mediated hemolysis potentially triggered by B19V. In one patient these complications lead to a fatal outcome. The review of the literature showed considerable morbidity of B19V infection with the potential for life-threatening complications. Most patients were treated by red blood cell transfusion and intravenous immunoglobulins (IVIG) with a high succession rate. CONCLUSION: Symptomatic B19V infection following HCT remains a rare but potentially challenging complication. A causal antiviral therapy does not exist as well as general recommendations on dosage and duration of IVIG therapy. Despite this, most patients are treated successfully with these measures. Additionally, transmission via blood or stem cell products is also rare and no general recommendations on B19V screenings exist.

SIRPα-specific monoclonal antibody enables antibody-dependent phagocytosis of neuroblastoma cells.

Immunotherapy with anti-GD2 monoclonal antibodies (mAbs) provides some benefits for patients with neuroblastoma (NB). However, the therapeutic efficacy remains limited, and treatment is associated with significant neuropathic pain. Targeting O-acetylated GD2 (OAcGD2) by 8B6 mAb has been proposed to avoid pain by more selective tumor cell targeting. Thorough understanding of its mode of action is necessary to optimize this treatment strategy. Here, we found that 8B6-mediated antibody-dependent cellular phagocytosis (ADCP) performed by macrophages is a key effector mechanism. But efficacy is limited by upregulation of CD47 expression on neuroblastoma cells in response to OAcGD2 mAb targeting, inhibiting 8B6-mediated ADCP. Antibody specific for the CD47 receptor SIRPα on macrophages restored 8B6-induced ADCP of CD47-expressing NB cells and improved the antitumor activity of 8B6 mAb therapy. These results identify ADCP as a critical mechanism for tumor cytolysis by anti-disialoganglioside mAb and support a combination with SIRPα blocking agents for effective neuroblastoma therapy.

Targeting CD10 on B-Cell Leukemia Using the Universal CAR T-Cell Platform (UniCAR).

Chimeric antigen receptor (CAR)-expressing T-cells are without a doubt a breakthrough therapy for hematological malignancies. Despite their success, clinical experience has revealed several challenges, which include relapse after targeting single antigens such as CD19 in the case of B-cell acute lymphoblastic leukemia (B-ALL), and the occurrence of side effects that could be severe in some cases. Therefore, it became clear that improved safety approaches, and targeting multiple antigens, should be considered to further improve CAR T-cell therapy for B-ALL. In this paper, we address both issues by investigating the use of CD10 as a therapeutic target for B-ALL with our switchable UniCAR system. The UniCAR platform is a modular platform that depends on the presence of two elements to function. These include UniCAR T-cells and the target modules (TMs), which cross-link the T-cells to their respective targets on tumor cells. The TMs function as keys that control the switchability of UniCAR T-cells. Here, we demonstrate that UniCAR T-cells, armed with anti-CD10 TM, can efficiently kill B-ALL cell lines, as well as patient-derived B-ALL blasts, thereby highlighting the exciting possibility for using CD10 as an emerging therapeutic target for B-cell malignancies.

Lenvatinib with etoposide plus ifosfamide in patients with refractory or relapsed osteosarcoma (ITCC-050): a multicentre, open-label, multicohort, phase 1/2 study.

BACKGROUND: Tyrosine kinase inhibitors have shown activity in osteosarcoma and might enhance the efficacy of chemotherapy. We aimed to determine the recommended phase 2 dose and antitumour activity of lenvatinib with etoposide plus ifosfamide in patients with refractory or relapsed osteosarcoma. METHODS: This multicentre, open-label, multicohort, phase 1/2 trial was done at 17 hospitals in six countries. Eligible patients were aged 2-25 years, had relapsed or refractory osteosarcoma, measurable or evaluable disease per Response Evaluation Criteria in Solid Tumors version 1.1, Lansky play-performance score or Karnofsky performance score of 50% or higher, up to one previous VEGF or VEGF receptor-targeted therapy, and a life expectancy of at least 3 months. This study includes a combination dose-finding phase 1 part (cohort 3A) and a phase 2 combination expansion in patients with osteosarcoma (cohort 3B). Lenvatinib was administered orally at a starting dose of 11 mg/m2 per day, capped at 24 mg per day, and etoposide (100 mg/m2 per day) plus ifosfamide (3000 mg/m2 per day) were administered intravenously on days 1-3 of each 21-day cycle for a maximum of five cycles. Lenvatinib monotherapy continued after these five cycles until disease progression, toxic effects, or patient choice to discontinue. The phase 1 primary endpoint was to determine the recommended phase 2 dose by evaluating dose-limiting toxicity and the phase 2 primary endpoint was progression-free survival at 4 months. Progression-free survival was measured in the full analysis set, which included all patients enrolled for efficacy outcomes; safety was assessed in all patients who received any study drug. This study is registered with ClinicalTrials.gov, NCT02432274. FINDINGS: 30 patients were screened for enrolment into cohort 3A between May 9, 2016, and June 3, 2019, and 22 patients for enrolment into cohort 3B between Sept 13, 2018, and July 18, 2019. Eight patients from cohort 3A and two from cohort 3B were ineligible for enrolment in the study. In phase 1, dose-limiting toxicities were observed in three patients (one in the lenvatinib 11 mg/m2 combination group and two in the 14 mg/m2 combination group) and the recommended phase 2 dose was determined as lenvatinib 14 mg/m2 per day (with daily dose cap of 24 mg) and etoposide 100 mg/m2 per day plus ifosfamide 3000 mg/m2 per day administered intravenously on days 1-3 of each 21-day cycle for a maximum of five cycles. 35 patients from phase 1 (cohort 3A; n=15) and phase 2 (cohort 3B; n=20) were treated at the recommended phase 2 dose and their results were pooled. Progression-free survival at 4 months was 51% (95% CI 34-69) in 18 of 35 patients per the binomial estimate. The most common grade 3-4 treatment-emergent adverse events were neutropenia (27 [77%] of 35), thrombocytopenia (25 [71%]), anaemia (19 [54%]), and decreased white blood cell count (19 [54%]). 26 [74%] of 35 patients had serious treatment-emergent adverse events and no treatment-related deaths occurred. INTERPRETATION: Lenvatinib with etoposide plus ifosfamide shows promising antitumour activity with no new safety signals in patients with refractory and relapsed osteosarcoma. These findings warrant further investigation in an ongoing randomised phase 2 study (NCT04154189). FUNDING: Eisai and Merck Sharp & Dohme.

tRNA-Dependent Import of a Transit Sequence-Less Aminoacyl-tRNA Synthetase (LeuRS2) into the Mitochondria of Arabidopsis.

Aminoacyl-tRNA synthetases (AaRS) charge tRNAs with amino acids for protein translation. In plants, cytoplasmic, mitochondrial, and chloroplast AaRS exist that are all coded for by nuclear genes and must be imported from the cytosol. In addition, only a few of the mitochondrial tRNAs needed for translation are encoded in mitochondrial DNA. Despite considerable progress made over the last few years, still little is known how the bulk of cytosolic AaRS and respective tRNAs are transported into mitochondria. Here, we report the identification of a protein complex that ties AaRS and tRNA import into the mitochondria of Arabidopsis thaliana. Using leucyl-tRNA synthetase 2 (LeuRS2) as a model for a mitochondrial signal peptide (MSP)-less precursor, a ≈30 kDa protein was identified that interacts with LeuRS2 during import. The protein identified is identical with a previously characterized mitochondrial protein designated HP30-2 (encoded by At3g49560) that contains a sterile alpha motif (SAM) similar to that found in RNA binding proteins. HP30-2 is part of a larger protein complex that contains with TIM22, TIM8, TIM9 and TIM10 four previously identified components of the translocase for MSP-less precursors. Lack of HP30-2 perturbed mitochondrial biogenesis and function and caused seedling lethality during greening, suggesting an essential role of HP30-2 in planta.

Redirecting T cells to treat solid pediatric cancers.

The capacity of single-agent therapy with immune checkpoint inhibitors to control solid cancers by unleashing preexisting local antitumor T cell responses has renewed interest in the broader use of T cells as anticancer therapeutics. At the same time, durable responses of refractory B-lineage malignancies to chimeric-receptor engineered T cells illustrate that T cells can be effectively redirected to cancers that lack preexisting tumor antigen-specific T cells, as most typical childhood cancers. This review summarizes strategies by which T cells can be modified to recognize defined antigens, with a focus on chimeric-receptor engineering. We provide an overview of candidate target antigens currently investigated in advanced preclinical and early clinical trials in pediatric malignancies and discuss the prerequisites for an adequate in vivo function of engineered T cells in the microenvironment of solid tumors and intrinsic and extrinsic limitations of current redirected T cell therapies. We further address innovative solutions to recruit therapeutic T cells to tumors, overcome the unreliable and heterogenous expression of most known tumor-associated antigens, and prevent functional inactivation of T cells in the hostile microenvironment of solid childhood tumors.

Assessment of treatment responses in children and adolescents with Ewing sarcoma with metabolic tumor parameters derived from 18F-FDG-PET/CT and circulating tumor DNA.

PURPOSE: The purpose of this study was to perform a prospective integrated analysis of 18F-fluorodeoxyglucose (18F-FDG)-positron emission tomography (PET)/computed tomography (CT) and circulating tumor DNA (ctDNA) to assess responses to multimodal chemotherapy in children and adolescents suffering from Ewing sarcoma (EwS). METHODS: A total of 20 patients with histologically confirmed EwS underwent multiple 18F-FDG-PET/CT, performed at the time of each patient's initial diagnosis and after the second and fifth induction chemotherapy block (EWING2008 treatment protocol, NCT00987636). Additional PET examinations were performed as clinically indicated in some patients, e.g., in patients suspected of having progressive or relapsing disease. All 263 18F-FDG-positive lesions in the field of view suggestive of tumor tissue were assessed quantitatively to calculate PET-derived parameters, including whole-body metabolic tumor volume (wb-MTV) and whole-body total lesion glycolysis (wb-TLG), as well as the following data: standardized uptake value (SUV)max and SUVmean. Tumor-specific ctDNA in patient plasma samples was quantified using digital droplet PCR (ddPCR), and the correlations between ctDNA levels and PET-derived parameters were analyzed. Metabolic responses to multimodal chemotherapy as assessed with PET-parameters were compared to biochemical responses as assessed with changes in ctDNA levels. RESULTS: Twenty patients underwent a total of 87 18F-FDG-PET/CT scans, which detected 263 FDG-positive tumor lesions. Significant correlations between SUVmax, SUVmean, wb-MTV and wb-TLG values, and ctDNA levels were observed (all p < 0.0001). All patients suffering from EwS, with histology serving as gold standard, also presented with a positive corresponding ctDNA sample and a positive 18F-FDG-PET/CT examination before initiation of therapy. There were no false-negative results. Evaluation of treatment response after the fifth block of induction chemotherapy showed that the agreement between the metabolic response and biochemical response was 90%, which was statistically significant (Cohen κ = 0.62; p < 0.05). Non-detectable ctDNA after the second block of induction chemotherapy was associated with complete biochemical and metabolic responses after the fifth block of induction chemotherapy in 16/17 patients (94%). During a median follow-up period of 36 months (range: 8-104 months), four patients had tumor relapses, which, in all cases, were accompanied by an increase in plasma ctDNA levels and a positive 18F-FDG-PET/CT. No false-negative results were observed in the study cohort. Complete biochemical and metabolic responses after the fifth block of induction chemotherapy had a high positive predictive value for disease remission during the follow-up period; specifically, the positive predictive value was 88%. CONCLUSION: The combination of 18F-FDG-PET/CT and ctDNA quantification is a very promising noninvasive tool for assessing treatment responses and detecting tumor relapses in children and young adolescents suffering from EwS who are undergoing multimodal chemotherapy.

Correction to: Assessment of treatment responses in children and adolescents with Ewing sarcoma with metabolic tumor parameters derived from 18F-FDG-PET/CT and circulating tumor DNA.

The author names and family names of the originally published article was inversed. Correct presentation is presented here.

Outcome of patients with Fanconi anemia developing myelodysplasia and acute leukemia who received allogeneic hematopoietic stem cell transplantation: A retrospective analysis on behalf of EBMT group.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is curative for bone marrow failure in patients with Fanconi anemia (FA), but the presence of a malignant transformation is associated with a poor prognosis and the management of these patients is still challenging. We analyzed outcome of 74 FA patients with a diagnosis of myelodysplastic syndrome (n = 35), acute leukemia (n = 35) or with cytogenetic abnormalities (n = 4), who underwent allo-HSCT from 1999 to 2016 in EBMT network. Type of diagnosis, pre-HSCT cytoreductive therapies and related toxicities, disease status pre-HSCT, donor type, and conditioning regimen were considered as main variables potentially influencing outcome. The 5-year OS and EFS were 42% (30-53%) and 39% (27-51%), respectively. Patients transplanted in CR showed better OS compared with those transplanted in presence of an active malignant disease (OS:71%[48-95] vs 37% [24-50],P = .04), while none of the other variables considered had an impact. Twenty-two patients received pre-HSCT cytoreduction and 9/22 showed a grade 3-4 toxicity, without any lethal event or negative influence on survival after HSCT(OS:toxicity pre-HSCT 48% [20-75%] vs no-toxicity 51% [25-78%],P = .98). The cumulative incidence of day-100 grade II-IV a-GvHD and of 5-year c-GvHD were 38% (26-50%) and 40% (28-52%). Non-relapse-related mortality and incidence of relapse at 5-years were 40% (29-52%) and 21% (11-30%) respectively, without any significant impact of the tested variables. Causes of death were transplant-related events in most patients (34 out of the 42 deaths, 81%). This analysis confirms the poor outcome of transformed FA patients and identifies the importance of achieving CR pre-HSCT, suggesting that, in a newly diagnosed transformed FA patient, a cytoreductive approach pre-HSCT should be considered if a donor have been secured.

VEGFR2 as a target for CAR T cell therapy of Ewing sarcoma.

BACKGROUND: T cells engineered to express chimeric antigen receptors (CARs) are a novel modality to treat refractory cancers. The development of CAR T cells against Ewing sarcoma (EwS) is limited by a lack of targetable surface antigens. We investigated vascular endothelial growth factor receptor 2 (VEGFR2) expressed on tumor-associated blood vessels as potential CAR target in this cancer. METHODS: Expression of VEGFR2 was studied by immunohistochemistry in human EwS biopsies and in murine xenografts and by flow cytometry in EwS cell lines. CARs with short, medium, and long hinge domains against either human or murine VEGFR2 were generated and expressed in human T cells by retroviral gene transfer. The capacity of the individual CARs to activate T cells in response to VEGFR2-expressing cells was compared in vitro. RESULTS: Tumor-associated endothelial cells in human EwS biopsies and in xenografts expressed VEGFR2. Tumor cells in the majority of EwS biopsies were also VEGFR2-positive. Following modification with anti-mouse or anti-human VEGFR2-specific CAR genes, T cells specifically lysed VEGFR2-expressing target cells of the respective species. CAR T cells with short-length or medium-length hinge domains were functionally superior over those with the long hinge region by in vitro parameters, including antigen-specific degranulation responses, lysis of tumor spheroids, tumor necrosis factor α secretion, sequential killing, and proliferation. CONCLUSIONS: VEGFR2 is consistently expressed on endothelial cells of the tumor stroma in EwS and thus is a candidate target for CAR T cells in this cancer. Among various VEGFR2-specific CARs, a construct with a short hinge domain was chosen to be further developed toward clinical translation.

Aneurysmal bone cyst inadvertently treated with chemotherapy-A series of three cases.

Aneurysmal bone cyst (ABC) is a benign locally aggressive tumor that occurs in childhood and early adulthood. Most relevant differential diagnoses are the telangiectatic osteosarcoma and the giant cell tumor. In the present case series chemotherapy following the EURAMOS or the Euro-Ewing 99 protocol was externally applied in three patients with the misdiagnosis of ABC as malignant bone tumor. In all three cases, a significant reduction of the volume of the ABC was achieved. This is the first report about the use of neoadjuvant chemotherapy in ABC. Chemotherapy reduces the size of an ABC and leads to progressive sclerosis.

EZH2 Inhibition in Ewing Sarcoma Upregulates GD2 Expression for Targeting with Gene-Modified T Cells.

Chimeric antigen receptor (CAR) engineering of T cells allows one to specifically target tumor cells via cell surface antigens. A candidate target in Ewing sarcoma is the ganglioside GD2, but heterogeneic expression limits its value. Here we report that pharmacological inhibition of Enhancer of Zeste Homolog 2 (EZH2) at doses reducing H3K27 trimethylation, but not cell viability, selectively and reversibly induces GD2 surface expression in Ewing sarcoma cells. EZH2 in Ewing sarcoma cells directly binds to the promoter regions of genes encoding for two key enzymes of GD2 biosynthesis, and EZH2 inhibition enhances expression of these genes. GD2 surface expression in Ewing sarcoma cells is not associated with distinct in vitro proliferation, colony formation, chemosensitivity, or in vivo tumorigenicity. Moreover, disruption of GD2 synthesis by gene editing does not affect its in vitro behavior. EZH2 inhibitor treatment sensitizes Ewing sarcoma cells to effective cytolysis by GD2-specific CAR gene-modified T cells. In conclusion, we report a clinically applicable pharmacological approach for enhancing efficacy of adoptively transferred GD2-redirected T cells against Ewing sarcoma, by enabling recognition of tumor cells with low or negative target expression.

Epidemiology, utilisation of healthcare resources and outcome of invasive fungal diseases following paediatric allogeneic haematopoietic stem cell transplantation.

BACKGROUND: Epidemiology and management practices of invasive fungal diseases (IFD) after allogeneic haematopoietic stem cell transplantation (HSCT) are a subject of constant change. We investigated the contemporary incidence, diagnostics, antifungal management and outcome at a major paediatric transplant centre in Germany. METHODS: The single-centre retrospective observational study included all paediatric allogeneic HSCT patients (pts) transplanted between 2005 and 2015. Patient-related data were assessed up to 365 days post-transplant. The primary endpoint was the incidence of possible, probable and proven IFDs. Secondary endpoints included diagnostics and antifungal treatment; analysis of risk factors; and overall survival with the last follow-up in January 2017. RESULTS: A total of 221 first (196), second (21) or third (4) procedures were performed in 200 pts (median age: 9 years, range, 0.5-22) for leukaemia/lymphoma (149) and non-malignant disorders (72). Prophylaxis was administered in 208 HSCT procedures (94%; fluconazole, 116, mould-active agents, 92). At least one computed tomography scan of the chest was performed in 146, and at least one galactomannan antigen assay in 60 procedures. There were 15 cases of proven (candidemia, 4; aspergillosis, 4) or probable (aspergillosis, 7) IFDs, accounting for an incidence rate of 6.8%. Overall mortality at last follow-up was 30%; the occurrence of proven/probable IFDs was associated with a reduced survival probability (P < .001). CONCLUSION: Morbidity and mortality from IFDs at our institution were consistent with data reported from other centres. Utilisation of healthcare resources for prevention, diagnosis and management of IFDs was considerable.

[Trans-Sectoral Patient Care in Pediatric Oncology: Quality Assurance by Novel Reimbursement Models for Outpatient Services]. / Sektorenübergreifende Versorgung in der Pädiatrischen Onkologie: Qualitätssicherung durch neue Vergütungsmodelle für nicht-vollstationäre Leistungen.

BACKGROUND: The medical care of pediatric cancer patients in the German health care system relies on special structures. All children and adolescents with a diagnosis of cancer receive uniform treatment within clinical studies or registers and exclusively at centers which can ensure interdisciplinary care by a multiprofessional team. Reimbursement of outpatient services is highly heterogeneous among the centers, and the expenses are often not adequately compensated. METHOD: A nation-wide survey was performed among all centers of the German Society of Pediatric Hematology and Oncology, with a standardized questionnaire inquiring which reimbursement models are used to finance outpatient treatment and whether full coverage of the expenses is achieved. RESULTS: Of 58 Pediatric Oncology Centers in Germany 18 (33%) participated in the survey, including 8 (44%) University Hospitals. The use of available reimbursement tools was highly heterogeneous. Reimbursement for outpatient service was based on a mean of 3,33±1,49 individual components. Of the 18 responding centers, 17 indicated that the revenues do not fully cover the expenses. DISCUSSION AND CONCLUSION: Pediatric oncology centers in Germany can not achieve full coverage of expenses in the outpatient setting. Nationally uniform cost-covering remuneration strategies are needed. This article proposes three individual models for an adequate nationwide financial framework for the outpatient care of pediatric cancer patients.