Prevalence and Outcomes of High versus Low Ratio Plasma to Red Blood Cell Resuscitation in a Multi-Institutional Cohort of Severely Injured Children.

BACKGROUND: The benefit of targeting high ratio fresh frozen plasma (FFP):red blood cell (RBC) transfusion in pediatric trauma resuscitation is unclear as existing studies are limited to patients who retrospectively met criteria for massive transfusion. The purpose of this study is to evaluate the use of high ratio FFP:RBC transfusion and the association with outcomes in children presenting in shock. METHODS: A post-hoc analysis of a 24-institution prospective observational study (4/2018-9/2019) of injured children <18 years with elevated age-adjusted shock index was performed. Patients transfused within 24 hours were stratified into cohorts of low (<1:2) or high (>1:2) ratio FFP:RBC. Nonparametric Kruskal-Wallis and chi-square were used to compare characteristics and mortality. Competing risks analysis was used to compare extended (≥75th percentile) ventilator, intensive care, and hospital days while accounting for early deaths. RESULTS: Of 135 children with median (IQR) age 10 (5,14) years and weight 40 (20,64) kg, 85 (63%) received low ratio transfusion and 50 (37%) high ratio despite similar activation of institutional massive transfusion protocols (MTP; low-38%, high-46%, p = .34). Most patients sustained blunt injuries (70%). Median injury severity score was greater in high ratio patients (low-25, high-33, p = .01); however, hospital mortality was similar (low-24%, high-20%, p = .65) as was the risk of extended ventilator, ICU, and hospital days (all p > .05). CONCLUSION: Despite increased injury severity, patients who received a high ratio of FFP:RBC had comparable rates of mortality. These data suggest high ratio FFP:RBC resuscitation is not associated with worst outcomes in children who present in shock. MTP activation was not associated with receipt of high ratio transfusion, suggesting variability in MTP between centers. LEVEL OF EVIDENCE: Prospective cohort study, Level II.

Reducing Constipation-Related Admissions: The Effectiveness of Antegrade Continence Enema Procedures in Children.

INTRODUCTION: Constipation in pediatrics remains a common problem. Antegrade continence enema (ACE) procedures have been shown to decrease the distress of daily therapy. Patients are able to administer more aggressive washouts in the outpatient setting. Therefore, we hypothesize that patients following an ACE procedure would have reduced admissions for constipation. METHODS: Patients who underwent an ACE procedure at a large children's hospital from 2015 to 2018 were included. Demographics, diagnosis, procedure, and preoperative/postoperative hospital admissions were analyzed. RESULTS: Forty-eight patients were included in the study. Over half were diagnosed with idiopathic constipation. Majority of patients underwent an appendicostomy (88%, n = 42). Preoperatively, 26 patients were admitted for a combined total of 63 times for constipation. Postoperatively, 4 patients were admitted for a total of 5 visits (P = .021). Twenty-eight patients required a nonscheduled appendicostomy tube replacement. CONCLUSION: This study demonstrates ACE procedures can improve constipation-related symptoms in children and are associated with decrease hospital admissions.

The Disturbing Findings of Pediatric Firearm Injuries From the National Trauma Data Bank: 2010-2016.

BACKGROUND: Trauma is the leading cause of pediatric and adolescent morbidity and mortality. Firearm-related injuries and deaths contribute substantially to the overall disease burden. This study described the intent, location, demographics, and outcomes of a nationally representative pediatric population with firearm injuries. We hypothesized that younger patients would have a higher percentage of unintentional and self-inflicted injuries with associated higher mortality rates. MATERIALS AND METHODS: The National Trauma Data Bank, maintained by the American College of Surgeons, from 2010 to 2016 was utilized. All pediatric patients (0-19 y) with firearm injuries who had complete data were analyzed for mechanism, location, demographics, and outcomes. Basic descriptive statistics were used to compare subgroups. Multivariable logistic regression analysis was applied to investigate risk factors for firearm injury-caused mortality. RESULTS: In the study period, 46,039 pediatric patients sustained firearm injuries (median age = 17 y). Males, Blacks, ages 15-19, and the Southern region were the most common injured demographics. However, subgroup analysis showed the demographics differ for self-inflicted and unintentional firearm injuries, which had significantly higher White patients (66.6% and 47.9%, respectively; P < 0.001). Nearly 76% of injuries were related to assaults, 14% were unintentional, 5% were self-inflicted, and 5% were undetermined. The overall mortality was nearly 12%. The youngest population had higher proportion of unintentional injuries and highest mortality rate when compared with other classifications of intent (P < 0.001). CONCLUSIONS: Pediatric firearm injuries have high mortality, especially in the youngest populations. Age-tailored prevention strategies, such as strict child access prevention laws and enforced gun storage violations, may help in reducing firearm injuries and improving health outcomes.

The One Health Consortium: Design of a Phase I Clinical Trial to Evaluate M032, a Genetically Engineered HSV-1 Expressing IL-12, in Combination With a Checkpoint Inhibitor in Canine Patients With Sporadic High Grade Gliomas.

As the most common and deadly of primary brain tumors, malignant gliomas have earned their place within one of the most multifaceted and heavily-funded realms of medical research. Numerous avenues of pre-clinical investigation continue to provide valuable insight, but modeling the complex evolution and behavior of these tumors within a host under simulated circumstances may pose challenges to extrapolation of data. Remarkably, certain breeds of pet dogs spontaneously and sporadically develop high grade gliomas that follow similar incidence, treatment, and outcome patterns as their human glioma counterparts. The most malignant of these tumors have been refractory to limited treatment options despite aggressive treatment; outcomes are dismal with median survivals of just over 1 year in humans and 2 months in dogs. Novel treatments are greatly needed and combination therapies appear to hold promise. This clinical protocol, a dose-escalating phase I study in dogs with sporadic malignant glioma, represents a first in comparative oncology and combination immunotherapy. The trial will evaluate M032, an Interleukin-12 expressing Herpes Simplex virus, alone and combined with a checkpoint inhibitor, Indoximod. Extensive pre-clinical work has demonstrated safety of intracranial M032 administration in mice and non-human primates. M032 is currently being tested in humans with high-grade malignant gliomas. Thus, in a novel fashion, both canine and human trials will proceed concurrently allowing a direct "head-to-head" comparison of safety and efficacy. We expect this viral oncolytic therapy to be as safe as it is in human patients and M032 to (a) infect and kill glioma cells, producing a virus and tumor cell antigen-rich debris field; (b) provide an adjuvant effect due to liberation of viral DNA, which is rich in unmethylated CpG sequences that "toggle" TLR-9 receptors; and (c) express IL-12 locally, stimulating induction of TH1 lymphocytes. The resultant immune-mediated anti-viral responses should, through cross-epitope spreading, translate into a strong response to tumor antigens. The ability to compare human and dog responses in real time affords the most stringent test of suitability of the dog as an informative model of human brain tumors. Subsequent studies will allow canine trials to properly inform the design of human trials.

Timing and volume of crystalloid and blood products in pediatric trauma: An Eastern Association for the Surgery of Trauma multicenter prospective observational study.

BACKGROUND: The purpose of this study was to determine the relationship between timing and volume of crystalloid before blood products and mortality, hypothesizing that earlier transfusion and decreased crystalloid before transfusion would be associated with improved outcomes. METHODS: A multi-institutional prospective observational study of pediatric trauma patients younger than 18 years, transported from the scene of injury with elevated age-adjusted shock index on arrival, was performed from April 2018 to September 2019. Volume and timing of prehospital, emergency department, and initial admission resuscitation were assessed including calculation of 20 ± 10 mL/kg crystalloid boluses overall and before transfusion. Multivariable Cox proportional hazards and logistic regression models identified factors associated with mortality and extended intensive care, ventilator, and hospital days. RESULTS: In 712 children at 24 trauma centers, mean age was 7.6 years, median (interquartile range) Injury Severity Score was 9 (2-20), and in-hospital mortality was 5.3% (n = 38). There were 311 patients(43.7%) who received at least one crystalloid bolus and 149 (20.9%) who received blood including 65 (9.6%) with massive transfusion activation. Half (53.3%) of patients who received greater than one crystalloid bolus required transfusion. Patients who received blood first (n = 41) had shorter median time to transfusion (19.8 vs. 78.0 minutes, p = 0.005) and less total fluid volume (50.4 vs. 86.6 mL/kg, p = 0.033) than those who received crystalloid first despite similar Injury Severity Score (median, 22 vs. 27, p = 0.40). On multivariable analysis, there was no association with mortality (p = 0.51); however, each crystalloid bolus after the first was incrementally associated with increased odds of extended ventilator, intensive care unit, and hospital days (all p < 0.05). Longer time to transfusion was associated with extended ventilator duration (odds ratio, 1.11; p = 0.04). CONCLUSION: Resuscitation with greater than one crystalloid bolus was associated with increased need for transfusion and worse outcomes including extended duration of mechanical ventilation and hospitalization in this prospective study. These data support a crystalloid-sparing, early transfusion approach for resuscitation of injured children. LEVEL OF EVIDENCE: Therapeutic, level IV.

Precision oncology: A primer for pediatric surgeons from the APSA cancer committee.

Although most children with cancer can be cured of their disease, a subset of patients with adverse tumor types or biological features, and those with relapsed or refractory disease have significantly worse prognosis. Furthermore, current cytotoxic therapy is associated with significant late effects. Precision oncology, using molecular therapeutics targeted against unique genetic features of the patient's tumor, offers the potential to transform the multimodal therapy for these patients. Potentiated by advances in sequencing technology and molecular therapeutic development, and accelerated by large-scale multi-institutional basket trials, the field of pediatric precision oncology has entered the mainstream. These novel therapeutics have important implications for surgical decision making, as well as pre- and postoperative care. This review summarizes the current state of precision medicine in pediatric oncology including the active North American and European precision oncology clinical trials. LEVEL OF EVIDENCE: Treatment study Level V.

A Synopsis of Pediatric Patients With Hepatoblastoma and Wilms Tumor: NSQIP-P 2012-2016.

BACKGROUND: Hepatoblastoma and Wilms tumor are the most common primary liver and kidney tumor in children, respectively, and little is documented about patient outcomes in the immediate perioperative period. The aim of this study was to analyze the short-term outcomes of pediatric patients after surgical resection for hepatoblastoma and Wilms tumor. METHODS: We queried the 2012-2016 ACS National Surgical Quality Improvement Program-Pediatric (NSQIP-P) database for patients with hepatoblastoma who underwent liver resection and patients with Wilms tumor who underwent a partial or total nephrectomy. Patient demographics, preoperative, intraoperative, and postoperative characteristics were analyzed. Multivariate logistic regression was used to determine independent risk factors for unplanned reoperations. RESULTS: There were a total of 189 patients with hepatoblastoma and 586 patients with Wilms in National Surgical Quality Improvement Program-Pediatric. The mean age of patients with hepatoblastoma was 3.1 y and 4.2 y in the Wilms group. Nine percent (n = 17) of patients underwent an unplanned reoperation after hepatectomy, and 4.1% (n = 24) of patients with Wilms experienced an unplanned reoperation. Over half of patients with hepatoblastoma (59.8%, n = 113) and 29.7% (n = 174) patients with Wilms tumor received a blood transfusion in the perioperative period. Patients in both groups demonstrated low rates of surgical site infections, but 6.3% (n = 12) of hepatoblastoma patients showed evidence of sepsis. CONCLUSIONS: This study will allow providers to more effectively counsel families of the common morbidities in the associated perioperative period following surgical resection of either solid tumor type including the substantial risk of blood transfusion.

Comparison of Pediatric and Adult Solid Pseudopapillary Neoplasms of the Pancreas.

BACKGROUND: Solid pseudopapillary neoplasms (SPPNs) comprise the majority of pediatric pancreatic neoplasms. We queried the National Cancer Database to compare pediatric and adult patients with SSPNs to examine differences in demographics, tumor characteristics, treatment, and overall survival. We aimed to determine if survival differences existed between adult and pediatric patients with SPPN. METHODS: The National Cancer Database (2004-2014) was reviewed, and patients were stratified by age at diagnosis: pediatric (≤21 y) and adult (≥22 y). Demographics, comorbidities, tumor characteristics, diagnostic periods, treatments, and survival rates were compared using pooled variance t-tests and chi-square, followed by multivariate Cox proportional hazard model (α = 0.05). Log-rank test was used to compare survival. RESULTS: A total of 468 patients were analyzed and categorized according to age group. Four hundred and fourteen patients were included in the survival analysis. The pediatric patients were primarily female, Caucasian, had no comorbidities, and presented with stage I disease. Race/ethnicity, gender, socioeconomic status, comorbidities, and disease stage at presentation were similar between the groups. There was no difference in time to initiation of therapy or to surgical intervention. No significant difference was found in type of surgical resection, chemotherapy, or radiotherapy utilization. Despite the similarities between groups, comparison of overall survival demonstrated improved survival of pediatric SPPN compared with adult SPPN in every pathologic stage. CONCLUSIONS: These results suggest that pediatric and adult SPPNs are similar with regards to demographics, tumor characteristics, and treatment modalities. However, survival was better in children with SPPNs, which may be due to differences in tumor biology and may serve for risk stratification of prognosis.

Pancreatic islet cell tumors in adolescents and young adults.

BACKGROUND: Pancreatic islet cell tumors are rare in adolescents, and most studies published to date focus on older patients. We utilized a national database to describe the histology and clinical pattern of pancreatic islet cell tumors in adolescent and young adult (AYA) patients, and to compare AYAs to older adults. We hypothesized that AYAs with pancreatic islet cell tumors would have better overall survival. METHODS: The National Cancer Data Base (NCDB, 1998-2012) was queried for AYA patients (15-39 years) with a pancreatic islet cell tumor diagnosis. Demographics, tumor characteristics, treatment modalities, and outcomes were abstracted and compared to adults (≥40 years). RESULTS: 383 patients (56.4% female, 65% non-Hispanic Whites) were identified, with a median age of 27 (IQR 16-34) years. Islet cell carcinoma was the most common histology. Of patients with known stage of disease, 49% presented with early stage (I or II). Seventy percent of patients underwent surgical resection, including local excision 44%, Whipple procedure 37.5%, or total pancreatectomy 19%. Chemotherapy was utilized in 27% and radiotherapy in 7%. All-cause mortality was 36%. AYA patients underwent more extensive resections (p = 0.001) and had lower mortality rates (p < 0.001), with no differences in tumor stage or use of adjuvant therapies, when compared to adults. CONCLUSIONS: AYA patients with pancreatic islet cell tumors had comparable utilization of adjuvant therapies but underwent more extensive resections and demonstrated a higher overall survival rate than adult counterparts. Further investigation into approaches to earlier diagnosis and tailoring of multimodality therapy of these neoplasms in the AYA population is needed. LEVELS OF EVIDENCE: Prognostic Study, Level II - retrospective study.

Investigation of PP2A and Its Endogenous Inhibitors in Neuroblastoma Cell Survival and Tumor Growth.

High-risk neuroblastoma continues to carry a poor prognosis. Nearly 50% of these tumors relapse following extensive treatment regimens. Protein phosphatase 2A (PP2A), a tumor suppressor, has been shown to be downregulated in many human cancers via multiple mechanisms including upregulation of its endogenous inhibitors, I2PP2A or CIP2A. We hypothesized that inhibition of the endogenous PP2A inhibitors or activation of PP2A would decrease tumorigenicity in human neuroblastoma cells. Four human neuroblastoma cell lines were utilized. Expression of PP2A and its endogenous inhibitors I2PP2A and CIP2A was confirmed by immunoblotting. PP2A activation was measured via phosphatase activation assay. Multiple parallel methods including siRNA inhibition of the endogenous PP2A inhibitors and pharmacologic activation of PP2A were utilized. Cell viability, proliferation, migration, and invasion assays were performed. In vivo studies were utilized to determine the effects of PP2A activation on neuroblastoma tumor growth. Inhibition of the endogenous inhibitors of PP2A or pharmacologic activation of PP2A with the PP2A activator FTY720 led to decreased neuroblastoma cell viability, proliferation, migration, and invasion. Treatment of mice bearing SK-N-AS or SK-N-BE(2) neuroblastoma tumors with FTY720 resulted in a significant decrease in tumor growth compared to vehicle-treated animals. In conclusion, activation of PP2A may provide a novel therapeutic target for neuroblastoma.

Targeting PIM kinase as a therapeutic strategy in human hepatoblastoma.

Increasing incidence coupled with poor prognosis and treatments that are virtually unchanged over the past 20 years have made the need for the development of novel therapeutics for hepatoblastoma imperative. PIM kinases have been implicated as drivers of tumorigenesis in multiple cancers, including hepatocellular carcinoma. We hypothesized that PIM kinases, specifically PIM3, would play a role in hepatoblastoma tumorigenesis and that PIM kinase inhibition would affect hepatoblastoma in vitro and in vivo. Parameters including cell survival, proliferation, motility, and apoptosis were assessed in human hepatoblastoma cells following PIM3 knockdown with siRNA or treatment with the PIM inhibitor AZD1208. An in vivo model of human hepatoblastoma was utilized to study the effects of PIM inhibition alone and in combination with cisplatin. PIM kinases were found to be present in the human hepatoblastoma cell line, HuH6, and in a human hepatoblastoma patient-derived xenograft, COA67. PIM3 knockdown or inhibition with AZD1208 decreased cell survival, attachment independent growth, and motility. Additionally, inhibition of tumor growth was observed in a hepatoblastoma xenograft model in mice treated with AZD1208. Combination therapy with AZD1208 and cisplatin resulted in a significant increase in animal survival when compared to either treatment alone. The current studies showed that PIM kinase inhibition decreased human hepatoblastoma tumorigenicity both in vitro and in vivo, implying that PIM inhibitors may be useful as a novel therapeutic for children with hepatoblastoma.

A novel retinoid X receptor agonist, UAB30, inhibits rhabdomyosarcoma cells in vitro.

BACKGROUND: While patients with early-stage rhabdomyosarcoma (RMS) have seen steady improvement in prognosis over the last 50 y, those with advanced-stage or high-grade disease continue to have a dismal prognosis. Retinoids have been shown to cause growth suppression and terminal differentiation in RMS cells, but the toxicities associated with retinoic acid limit its use. Rexinoids provide an alternative treatment approach to retinoic acid. Rexinoids primarily bind the retinoid X receptor with minimal retinoic acid receptor binding, the entity responsible for many of the toxicities of retinoid therapies. UAB30 is a novel rexinoid with limited toxicities. We hypothesized that UAB30 would lead to decreased cell survival in RMS. MATERIALS AND METHODS: Two RMS cell lines, one embryonal (RD) subtype and one alveolar (St. Jude Cancer Research Hospital 30) subtype, were used. Cells were treated with UAB30, and cytotoxicity, proliferation, mobility, and apoptosis were evaluated. RESULTS: UAB30 significantly decreased RMS tumor cell viability and proliferation. Invasion, migration, and attachment-independent growth were reduced following UAB30 treatment. UAB30 also resulted in apoptosis and G1 cell cycle arrest. UAB30 affected both the alveolar and embryonal RMS cell lines in a similar fashion. CONCLUSIONS: The results of these studies suggest a potential therapeutic role for the low-toxicity synthetic retinoid X receptor selective agonist, UAB30, in RMS treatment.

Rationale and Design of a Phase 1 Clinical Trial to Evaluate HSV G207 Alone or with a Single Radiation Dose in Children with Progressive or Recurrent Malignant Supratentorial Brain Tumors.

Primary central nervous system tumors are the most common solid neoplasm of childhood and the leading cause of cancer-related death in pediatric patients. Survival rates for children with malignant supratentorial brain tumors are poor despite aggressive treatment with combinations of surgery, radiation, and chemotherapy, and survivors often suffer from damaging lifelong sequelae from current therapies. Novel innovative treatments are greatly needed. One promising new approach is the use of a genetically engineered, conditionally replicating herpes simplex virus (HSV) that has shown tumor-specific tropism and potential efficacy in the treatment of malignant brain tumors. G207 is a genetically engineered HSV-1 lacking genes essential for replication in normal brain cells. Safety has been established in preclinical investigations involving intracranial inoculation in the highly HSV-sensitive owl monkey (Aotus nancymai), and in three adult phase 1 trials in recurrent/progressive high-grade gliomas. No dose-limiting toxicities were seen in the adult studies and a maximum tolerated dose was not reached. Approximately half of the 35 treated adults had radiographic or neuropathologic evidence of response at a minimum of one time point. Preclinical studies in pediatric brain tumor models indicate that a variety of pediatric tumor types are highly sensitive to killing by G207. This clinical protocol outlines a first in human children study of intratumoral inoculation of an oncolytic virus via catheters placed directly into recurrent or progressive supratentorial malignant tumors.

Effect of Repeat Dosing of Engineered Oncolytic Herpes Simplex Virus on Preclinical Models of Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS), a tumor of skeletal muscle origin, is the most common sarcoma of childhood. Despite multidrug chemotherapy regimens, surgical intervention, and radiation treatment, outcomes remain poor, especially in advanced disease, and novel therapies are needed for the treatment of these aggressive malignancies. Genetically engineered oncolytic viruses, such as herpes simplex virus-1 (HSV), are currently being explored as treatments for pediatric tumors. M002, an oncolytic HSV, has both copies of the γ134.5 gene deleted, enabling replication in tumor cells but thwarting infection of normal, postmitotic cells. We hypothesized that M002 would infect human RMS tumor cells and lead to decreased tumor cell survival in vitro and impede tumor growth in vivo. In the current study, we demonstrated that M002 could infect, replicate in, and decrease cell survival in both embryonal (ERMS) and alveolar rhabdomyosarcoma (ARMS) cells. Additionally, M002 reduced xenograft tumor growth and increased animal survival in both ARMS and ERMS. Most importantly, we showed for the first time that repeated dosing of oncolytic virus coupled with low-dose radiation provided improved tumor response in RMS. These findings provide support for the clinical investigation of oncolytic HSV in pediatric RMS.

Oncolytic virotherapy for pediatric malignancies: future prospects.

Pediatric solid tumors remain a major health concern, with nearly 16,000 children diagnosed each year. Of those, ~2,000 succumb to their disease, and survivors often suffer from lifelong disability secondary to toxic effects of current treatments. Countless multimodality treatment regimens are being explored to make advances against this deadly disease. One targeted treatment approach is oncolytic virotherapy. Conditionally replicating viruses can infect tumor cells while leaving normal cells unharmed. Four viruses have been advanced to pediatric clinical trials, including herpes simplex virus-1, Seneca Valley virus, reovirus, and vaccinia virus. In this review, we discuss the mechanism of action of each virus, pediatric preclinical studies conducted to date, past and ongoing pediatric clinical trials, and potential future direction for these novel viral therapeutics.

Targeting Focal Adhesion Kinase Suppresses the Malignant Phenotype in Rhabdomyosarcoma Cells.

Despite the tremendous advances in the treatment of childhood solid tumors, rhabdomyosarcoma (RMS) continues to provide a therapeutic challenge. Children with metastatic or relapsed disease have a disease-free survival rate under 30%. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of tumorigenesis. Signaling pathways both upstream and downstream to FAK have been found to be important in sarcoma tumorigenesis, leading us to hypothesize that FAK would be present in RMS and would impact cellular survival. In the current study, we showed that FAK was present and phosphorylated in pediatric alveolar and embryonal RMS tumor specimens and cell lines. We also examined the effects of FAK inhibition upon two RMS cell lines utilizing parallel approaches including RNAi and small molecule inhibitors. FAK inhibition resulted in decreased cellular survival, invasion, and migration and increased apoptosis. Furthermore, small molecule inhibition of FAK led to decreased tumor growth in a nude mouse RMS xenograft model. The findings from this study will help to further our understanding of the regulation of tumorigenesis in RMS and may provide desperately needed novel therapeutic strategies for these difficult-to-treat tumors.

Preclinical Evaluation of UAB30 in Pediatric Renal and Hepatic Malignancies.

Rare tumors of solid organs remain some of the most difficult pediatric cancers to cure. These difficult tumors include rare pediatric renal malignancies, such as malignant rhabdoid kidney tumors (MRKT) and non-osseous renal Ewing sarcoma, and hepatoblastoma, a pediatric liver tumor that arises from immature liver cells. There are data in adult renal and hepatic malignancies demonstrating the efficacy of retinoid therapy. The investigation of retinoic acid therapy in cancer is not a new strategy, but the widespread adoption of this therapy has been hindered by toxicities. Our laboratory has been investigating a novel synthetic rexinoid, UAB30, which exhibits a more favorable side-effect profile. In this study, we hypothesized that UAB30 would diminish the growth of tumor cells from both rare renal and liver tumors in vitro and in vivo We successfully demonstrated decreased cellular proliferation, invasion and migration, cell-cycle arrest, and increased apoptosis after treatment with UAB30. Additionally, in in vivo murine models of human hepatoblastoma or rare human renal tumors, there were significantly decreased tumor xenograft growth and increased animal survival after UAB30 treatment. UAB30 should be further investigated as a developing therapeutic in these rare and difficult-to-treat pediatric solid organ tumors. Mol Cancer Ther; 15(5); 911-21. ©2016 AACR.

Pediatric cancer gone viral. Part II: potential clinical application of oncolytic herpes simplex virus-1 in children.

Oncolytic engineered herpes simplex viruses (HSVs) possess many biologic and functional attributes that support their use in clinical trials in children with solid tumors. Tumor cells, in an effort to escape regulatory mechanisms that would impair their growth and progression, have removed many mechanisms that would have protected them from virus infection and eventual virus-mediated destruction. Viruses engineered to exploit this weakness, like mutant HSV, can be safely employed as tumor cell killers, since normal cells retain these antiviral strategies. Many preclinical studies and early phase trials in adults demonstrated that oncolytic HSV can be safely used and are highly effective in killing tumor cells that comprise pediatric malignancies, without generating the toxic side effects of nondiscriminatory chemotherapy or radiation therapy. A variety of engineered viruses have been developed and tested in numerous preclinical models of pediatric cancers and initial trials in patients are underway. In Part II of this review series, we examine the preclinical evidence to support the further advancement of oncolytic HSV in the pediatric population. We discuss clinical advances made to date in this emerging era of oncolytic virotherapy.

Pediatric cancer gone viral. Part I: strategies for utilizing oncolytic herpes simplex virus-1 in children.

Progress for improving outcomes in pediatric patients with solid tumors remains slow. In addition, currently available therapies are fraught with numerous side effects, often causing significant life-long morbidity for long-term survivors. The use of viruses to kill tumor cells based on their increased vulnerability to infection is gaining traction, with several viruses moving through early and advanced phase clinical testing. The prospect of increased efficacy and decreased toxicity with these agents is thus attractive for pediatric cancer. In part I of this two-part review, we focus on strategies for utilizing oncolytic engineered herpes simplex virus (HSV) to target pediatric malignancies. We discuss mechanisms of action, routes of delivery, and the role of preexisting immunity on antitumor efficacy. Challenges to maximizing oncolytic HSV in children are examined, and we highlight how these may be overcome through various arming strategies. We review the preclinical and clinical evidence demonstrating safety of a variety of oncolytic HSVs. In Part II, we focus on the antitumor efficacy of oncolytic HSV in pediatric tumor types, pediatric clinical advances made to date, and future prospects for utilizing HSV in pediatric patients with solid tumors.