Development of Molecularly Targeted Therapies to Treat Pediatric Malignancies

Utilization of Genomic Tumor Profiling in Pediatric Liquid Tumors: A Clinical Series

Hematologic tumors are mostly treated with chemotherapies that have poor toxicity profiles. While molecular tumor profiling can expand therapeutic options, our understanding of potential targetable drivers comes from studies of adult liquid tumors, which does not necessarily translate to efficacious treatment in pediatric liquid tumors. There is also no consensus on when profiling should be performed and its use in guiding therapies. We describe a single institution's experience in integrating profiling for liquid tumors. Pediatric patients diagnosed with leukemia or lymphoma and who underwent tumor profiling were retrospectively reviewed. Ten (83.3%) patients had relapsed disease prior to tumor profiling. Eleven (91.7%) patients had targetable alterations identified on profiling, and three (25%) received targeted therapy based on these variants. Of the three patients that received targeted therapy, two (66.7%) were living, and one (33.3%) decreased. For a portion of our relapsing and/or treatment-refractory patients, genetic profiling was feasible and useful in tailoring therapy to obtain stable or remission states. Practitioners may hesitate to deviate from the 'standard of therapy', resulting in the underutilization of profiling results. Prospective studies should identify actionable genetic variants found more frequently in pediatric liquid tumors and explore the benefits of proactive tumor profiling prior to the first relapse.

Lessons Learned: Utilization of a Reference Laboratory for Targeted Sequencing of Pediatric Tumors at a Single Institution

Our study aims to report the prevalence of potentially actionable oncogenic variants in a sample of pediatric tumors from a single institution using a reference laboratory for tumor profiling. We investigated genomic alterations and immunotherapy biomarkers such a tumor mutation burden, microsatellite instability, and programmed death-ligand 1. Patients treated in the Cook Children's Health Care System who had tumor profiling performed by Foundation Medicine between January 1, 2013, and May 1, 2019, were included. Demographic variables, results of tumor profiling, and subsequent use of targeted therapies were captured. Eighty-one patients were in our final data set; patients had diagnoses of central nervous system tumors (n=5), leukemia and lymphoma (n=4), neuroblastoma (n=32), and other solid tumors (n=40). One or more genomic alterations were identified in 68 (84%) of patients, 34 of which had potential targeted therapies available. In all, 44/51 patients tested for tumor mutation burden had low tumor burden, and the rest had intermediate burden. All 41 patients tested for microsatellite instability status were microsatellite stable. Six of 34 patients tested for programmed death-ligand 1 status were positive. Twelve patients received targeted therapy. This study highlights a subset of pediatric tumors harboring targetable genetic alterations and describes the use of a reference laboratory for tumor profiling.

Basic research in childhood cancer: Progress and future directions in China

Childhood cancer is a leading cause of death in children. Some childhood cancers have a particularly high mortality rate. Following the World Health Organization's emphasis on child health, most governments worldwide have taken measures to facilitate childhood cancer research. Thus, the scientific community is showing increasing interest in this area. Chinese government has prominence in building a system for the diagnosis and treatment of childhood cancer, thereby promoting the development of childhood cancer research. This review summarizes the research progress, challenges, and perspectives in childhood cancer, and the increasing contributions of National Natural Science Foundation of China (NSFC) in the past decade (2008-2018).

The Relationship between Anxiety and Immunity in Pediatric Oncology Patients

Background: Pediatric onco-hematology is not a frequently encountered medical specialty, and it influences everyday life, basic activities, and the immune system, mostly through psychosocial changes, which may affect every individual and their families differently. Anxiety is the most frequently encountered mental health disorder occurring during childhood and adolescence. The effect of stress and anxiety on the immune system is suggested by the fact that stress hormones elevate proinflammatory cytokines and subsequently lower the anti-inflammatory response.

Objective: Our main objective was to analyze the relationship between anxiety disturbance and cytokine levels in oncologic pediatric patients from Târgu Mureș in order to answer the following question: does anxiety influence immunity?

Material and methods: After testing pediatric oncology patients from the Pediatrics Clinic no. 2 of Târgu Mureș, Romania with the SCARED child test, we took blood samples from each participant. IL-6, IL-10, IL-1β, IL-12p40 and TNF-α levels were evaluated with a Human Cytokine Magnetic Panel using the xMAP technique on Flexmap 3D platform (Luminex Corporation, Austin, USA). C-reactive protein levels were determined with the BN Pro Spec nephelometer with CardioPhase hsCRP (Siemens Healthcare Diagnostics, GmbH, Marburg, Germany) reagent.

Results: The 46 pediatric oncology patients had 6 main diagnostic groups, the most frequent pathology was acute leukemia (58.7%) followed by malignant solid tumors (21.74%) and lymphomas (6.52%). In the anxious group (45.65%) we observed 4 of the 5 studied anxiety types: panic disorder, separation, social, and generalized anxiety. We measured the cytokine levels of all the participants from the two main groups: anxious/non-anxious. Statistical analysis (linear regression) showed statistically significant positive correlations in the anxious group related to the IL-1β and IL-6, a moderate/weak correlation related to IL-12p40, as well as a negative moderate correlation between IL-10 values in the anxious group and a positive trend in the non-anxious group.

Conclusions: Psycho-oncology is a relatively young specialty with few studies in the last two decades. IL-1β, IL-6, and TNF-α present high levels in anxious patients, while IL-10 and IL-12p40 have low serum levels in mental disorders. C-reactive protein levels are not influenced by anxiety.

Broad Spectrum Activity of the Checkpoint Kinase 1 Inhibitor Prexasertib as a Single Agent or Chemopotentiator Across a Range of Preclinical Pediatric Tumor Models

PURPOSE

Checkpoint kinase 1 (CHK1) inhibitors potentiate the DNA-damaging effects of cytotoxic therapies and/or promote elevated levels of replication stress, leading to tumor cell death. Prexasertib (LY2606368) is a CHK1 small-molecule inhibitor under clinical evaluation in multiple adult and pediatric cancers. In this study, prexasertib was tested in a large panel of preclinical models of pediatric solid malignancies alone or in combination with chemotherapy.

EXPERIMENTAL DESIGN

DNA damage and changes in cell signaling following in vitro prexasertib treatment in pediatric sarcoma cell lines were analyzed by Western blot and high content imaging. Antitumor activity of prexasertib as a single agent or in combination with different chemotherapies was explored in cell line-derived (CDX) and patient-derived xenograft (PDX) mouse models representing nine different pediatric cancer histologies.

RESULTS

Pediatric sarcoma cell lines were highly sensitive to prexasertib treatment in vitro, resulting in activation of the DNA damage response. Two PDX models of desmoplastic small round cell tumor and one malignant rhabdoid tumor CDX model responded to prexasertib with complete regression. Prexasertib monotherapy also elicited robust responses in mouse models of rhabdomyosarcoma. Concurrent administration with chemotherapy was sufficient to overcome innate resistance or prevent acquired resistance to prexasertib in preclinical models of neuroblastoma, osteosarcoma, and Ewing sarcoma, or alveolar rhabdomyosarcoma, respectively.

CONCLUSIONS

Prexasertib has significant antitumor effects as a monotherapy or in combination with chemotherapy in multiple preclinical models of pediatric cancer. These findings support further investigation of prexasertib in pediatric malignancies.