Cellules endothéliales circulantes et progéniteurs endothéliaux circulants (biomarqueurs de l'angiogénèse tumorale et des traitements anti-angiogéniques et anti-vasculaires.)

Malgré l efficacité thérapeutique avérée des agents anti-angiogéniques et des agents anti-vasculaires (VDA), le mécanisme d action précis des stratégies ciblant les vaisseaux sanguins tumoraux, les raisons de leur efficacité ainsi que les mécanismes de résistance à ces drogues sont encore mal compris. Il est rapidement apparu essentiel d identifier des biomarqueurs capables de refléter l angiogénèse tumorale ou les effets sur la vascularisation tumorale de ces traitements. Compte tenu de leur importance dans des pathologies vasculaires, les cellules endothéliales matures circulantes (CEC) et les progéniteurs endothéliaux circulants (CEP) ont d emblée été pressenties comme des candidats intéressants pour être des biomarqueurs de réponse aux stratégies ciblant la vascularisation tumorale. Nous avons exploré l intérêt de ces cellules en tant que biomarqueurs de l angiogénèse dans des tumeurs pédiatriques, et leur rôle en tant que biomarqueurs de traitement par des agents anti-angiogéniques chez des sujets adultes atteints de cancer. Ces travaux ont mis en lumière l intérêt des CEP et ont été à la source d un travail plus mécanistique où nous avons étudié dans différents modèles murins le rôle des CEC et CEP dans le mécanisme d action des agents anti-vasculaires et plus particulièrement le rôle fonctionnel des CEP dans la résistance à ces molécules. Par des stratégies d association d agents anti-angiogéniques aux VDA destinées à inhiber les CEP, nous montrons l augmentation de l activité anti-tumorale des VDA et offrons un rationnel mécanistique pour optimiser les schémas thérapeutiques actuels des traitements anti-vasculaires. Nos données apportent des arguments en faveur du rôle potentiel de ces cellules en tant que biomarqueurs de l angiogénèse, des traitements anti-angiogéniques et de la résistance aux traitements anti-vasculaires.Despite their therapeutic impact and clinical benefit, the mecanisms of action of anti-angiogenic agents and vascular disrupting agents (VDA), the reasons for their efficacy as well as the mechanisms underlying resistance to these drugs are not fully understood. Thus, identifying surrogate biomarkers of tumor angiogenesis and of the effects of these new therapeutic agents targeting tumor blood vessels has become a crucial objective. Because of their importance in vascular diseases, mature circulating endothelial cells (CEC) and circulating endothelial progenitor cells (CEP) were suggested to be potential candidate biomarkers of disease response and relapse to vascular targeting strategies. We investigated the role of these cells as biomarkers of tumor angiogenesis in pediatric solid tumors, as well as biomarkers of response to anti-angiogenic therapies in adult cancer patients. By revealing the particularly important role of CEP, these initial studies led to a more mechanistic study in which the cellular and molecular effects of a VDA were evaluated with regard to CEC and CEP in different mouse models; in particular, the catalytic role of CEP was explored as a mechanism of resistance to VDA. By combining anti-angiogenic agents aimed to inhibit CEP mobilized by the VDA, we demonstrate an increase in the anti-tumor activity of the VDA and offer a mechanistic rational to optimize VDA-based therapeutic strategies. Our data support the role of CEC and CEP as biomarkers of angiogenesis, of anti-angiogenic strategies and of resistance to vascular-disrupting therapies.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Market access to new anticancer medicines for children and adolescents with cancer in Europe

BACKGROUND AND AIMS: There is an alarming delay in Europe for anticancer medicines becoming accessible for children. Following a paediatric European Union marketing authorisation, national Health Technology Assessment (HTA) agencies evaluate effectiveness, and safety of medicines to support decision on their cost and reimbursement. This study (a SIOPE Access to Medicines project) aimed to evaluate how these HTA evaluations take place for anticancer medicines indicated for paediatric use in Europe and to explore where the delays for market access originate. METHODS: We obtained HTA reports from the public domain for nine European countries for blinatumomab, dinutuximab beta and tisagenlecleucel. We evaluated the time elapsed between marketing authorisation for a paediatric indication and a national HTA decision and the nature of the decision. RESULTS: Out of 23 HTA decisions (four countries without blinatumomab report), 18 were positive, two with restrictions, three negative. For blinatumomab, tisagenlecleucel and dinutuximab beta, the median time to an HTA decision after regulatory approval for paediatric use was 353 days (range 193-751), 141 days (range 77-517) and 515 days (range 0-780), respectively, with variability between countries. Dinutuximab beta and tisagenlecleucel were first introduced in children, but did not result in shorter time to HTA decision. For blinatumomab, marketing authorisation followed 1008 days after the indication in adults, with HTA applications submitted a median of 167 days later, and a recommendation after 145 days. CONCLUSIONS: This study reveals ample variability in HTA decision making in nine European Union countries. Collaboration and alignment of required evidence is needed to facilitate robust scientific HTA assessments, also considering methodological challenges in paediatric oncology

Market access to new anticancer medicines for children and adolescents with cancer in Europe

Background and aims: There is an alarming delay in Europe for anticancer medicines becoming accessible for children. Following a paediatric European Union marketing authorisation, national Health Technology Assessment (HTA) agencies evaluate effectiveness, and safety of medicines to support decision on their cost and reimbursement. This study (a SIOPE Access to Medicines project) aimed to evaluate how these HTA evaluations take place for anticancer medicines indicated for paediatric use in Europe and to explore where the delays for market access originate. Methods: We obtained HTA reports from the public domain for nine European countries for blinatumomab, dinutuximab beta and tisagenlecleucel. We evaluated the time elapsed between marketing authorisation for a paediatric indication and a national HTA decision and the nature of the decision. Results: Out of 23 HTA decisions (four countries without blinatumomab report), 18 were positive, two with restrictions, three negative. For blinatumomab, tisagenlecleucel and dinutuximab beta, the median time to an HTA decision after regulatory approval for paediatric use was 353 days (range 193–751), 141 days (range 77–517) and 515 days (range 0–780), respectively, with variability between countries. Dinutuximab beta and tisagenlecleucel were first introduced in children, but did not result in shorter time to HTA decision. For blinatumomab, marketing authorisation followed 1008 days after the indication in adults, with HTA applications submitted a median of 167 days later, and a recommendation after 145 days. Conclusions: This study reveals ample variability in HTA decision making in nine European Union countries. Collaboration and alignment of required evidence is needed to facilitate robust scientific HTA assessments, also considering methodological challenges in paediatric oncology

Portrait of Ependymoma Recurrence in Children: Biomarkers of Tumor Progression Identified by Dual-Color Microarray-Based Gene Expression Analysis

BACKGROUND: Children with ependymoma may experience a relapse in up to 50% of cases depending on the extent of resection. Key biological events associated with recurrence are unknown. METHODOLOGY/PRINCIPAL FINDINGS: To discover the biology behind the recurrence of ependymomas, we performed CGHarray and a dual-color gene expression microarray analysis of 17 tumors at diagnosis co-hybridized with the corresponding 27 first or subsequent relapses from the same patient. As treatment and location had only limited influence on specific gene expression changes at relapse, we established a common signature for relapse. Eighty-seven genes showed an absolute fold change ≥2 in at least 50% of relapses and were defined as the gene expression signature of ependymoma recurrence. The most frequently upregulated genes are involved in the kinetochore (ASPM, KIF11) or in neural development (CD133, Wnt and Notch pathways). Metallothionein (MT) genes were downregulated in up to 80% of the recurrences. Quantitative PCR for ASPM, KIF11 and MT3 plus immunohistochemistry for ASPM and MT3 confirmed the microarray results. Immunohistochemistry on an independent series of 24 tumor pairs at diagnosis and at relapse confirmed the decrease of MT3 expression at recurrence in 17/24 tumor pairs (p = 0.002). Conversely, ASPM expression was more frequently positive at relapse (87.5% vs 37.5%, p = 0.03). Loss or deletion of the MT genes cluster was never observed at relapse. Promoter sequencing after bisulfite treatment of DNA from primary tumors and recurrences as well as treatment of short-term ependymoma cells cultures with a demethylating agent showed that methylation was not involved in MT3 downregulation. However, in vitro treatment with a histone deacetylase inhibitor or zinc restored MT3 expression. CONCLUSIONS/SIGNIFICANCE: The most frequent molecular events associated with ependymoma recurrence were over-expression of kinetochore proteins and down-regulation of metallothioneins. Metallothionein-3 expression is epigenetically controlled and can be restored in vitro by histone deacetylase inhibitors

The organization of care in pediatric radiotherapy across SIOP Europe affiliated centers:A multicenter survey in the framework of the 'Joint Action on Rare Cancers' project

BACKGROUND/PURPOSE: To reduce inequalities among SIOPE-affiliated countries, standard and optional levels to deliver 'Good Clinical Practice' compliant treatment in pediatric radiation oncology have been published. The aim of this project was to map the availability of pediatric radiotherapy resources across SIOPE-affiliated radiotherapy departments.MATERIALS/METHODS: An online survey with 34 questions was distributed to 246 radiotherapy departments across 35 SIOPE-affiliated countries. In addition to demographic data, 15 general items related to the organization of the radiotherapy process, and 10 radiotherapy-specific items were defined. For each of the 25 items, sum scores were calculated per center and country. Mann-Whitney U tests were used to analyze associations.RESULTS: Between March-June 2019, 121 departments (49 %) out of 31 countries (89 %) completed the survey. At center level, involvement of core disciplines in tumor boards (28 %), and integration of dedicated pediatric radiation therapy technologists (24 %) are limited, while rare &amp; complex brachytherapy procedures are performed in many centers (23 %). For general and radiotherapy-specific items respectively, a relevant variation of sum scores was observed across countries (Δgeneral: ≤10 points; ΔRT_specific: ≤5 points) and among centers within a country (Δgeneral: ≤9 points; ΔRT_specific: ≤6 points). Sum scores for general and radiotherapy-specific items were higher in countries with a high-income (p &lt; 0.01) and higher health development index (p &lt; 0.01). A larger annual number of irradiated pediatric patients was associated with higher sum scores for general items (p &lt; 0.01).CONCLUSION: This survey demonstrates the disparities in organization of pediatric radiotherapy departments between SIOPE-affiliated countries and centers within the same country. Investment is needed to reduce inequalities in pediatric radiotherapy care.</p

Clinical, methodology, and patient/carer expert advice in pediatric drug development by conect4children

Many medicines are used “off-label” in children outside the terms of the license. Feasible pediatric clinical trials are a challenge to design. Conect4children (c4c) is an Innovative Medicines Initiative project to set up a pan-European pediatric clinical trial network aiming to facilitate the development of new medicines for children. To optimize pediatric trial development by promoting innovative trial design, c4c set up a European multidisciplinary advice service, including the voice of young patients and families, tailored to industry and academia. A network of experts was established to provide multidisciplinary advice to trial sponsors. Experts were selected to join clinical and innovative methodology expert groups. A patient and public involvement (PPI) database, to include the expert opinion of patients and parents/carers was formed. A stepwise process was developed: (1) sponsors contact c4c, (2) scoping interview takes place, (3) ad hoc advice group formed, (5) advice meeting held, and (6) advice report provided. Feedback on the process was collected. Twenty-four clinical and innovative methodology expert groups (&gt;400 experts) and a PPI database of 135 registrants were established. As of September 30, 2022, 36 advice requests were received, with 25 requests completed. Clinical and methodology experts and PPI representatives participated in several advice requests. Sponsors appreciated the advice quality and the multidisciplinary experts from different countries, including experts not known before. Experts and PPI participants were generally satisfied with the process. The c4c project has shown successful proof of concept for a service that presents a new framework to plan innovative and feasible pediatric trials.</p

MGMT-independent temozolomide resistance in pediatric glioblastoma cells associated with a PI3-kinase-mediated HOX/stem cell gene signature

Sensitivity to temozolomide is restricted to a subset of glioblastoma patients, with the major determinant of resistance being a lack of promoter methylation of the gene encoding the repair protein DNA methyltransferase MGMT, although other mechanisms are thought to be active. There are, however, limited preclinical data in model systems derived from pediatric glioma patients. We screened a series of cell lines for temozolomide efficacy in vitro, and investigated the differential mechanisms of resistance involved. In the majority of cell lines, a lack of MGMT promoter methylation and subsequent protein overexpression were linked to temozolomide resistance. An exception was the pediatric glioblastoma line KNS42. Expression profiling data revealed a coordinated upregulation of HOX gene expression in resistant lines, especially KNS42, which was reversed by phosphoinositide 3-kinase pathway inhibition. High levels of HOXA9/HOXA10 gene expression were associated with a shorter survival in pediatric high-grade glioma patient samples. Combination treatment in vitro of pathway inhibition and temozolomide resulted in a highly synergistic interaction in KNS42 cells. The resistance gene signature further included contiguous genes within the 12q13-q14 amplicon, including the Akt enhancer PIKE, significantly overexpressed in the KNS42 line. These cells were also highly enriched for CD133 and other stem cell markers. We have thus shown an in vitro link between phosphoinositide 3-kinase-mediated HOXA9/HOXA10 expression, and a drug-resistant, progenitor cell phenotype in MGMT-independent pediatric glioblastoma.Cancer Research UK (C1178/A10294, C309/A2187, C309/A8274), the Oak Foundation (L. Marshall), and La Fondation de France (N. Gaspar). We acknowledge NHS funding to the NIHR Biomedical Research Centre. P. Workman is a Cancer Research UK Life Fello