Challenges and Opportunities for Childhood Cancer Drug Development

Population-level 5-year event-free survival for children with cancer in Australia

BACKGROUND

Event-free survival (EFS) considers other adverse events in addition to mortality. It therefore provides a more complete understanding of the effectiveness and consequences of treatment than standard survival measures, but is rarely reported at the population level for childhood cancer.

PROCEDURE

Our study cohort (n = 7067) was obtained from the Australian Childhood Cancer Registry, including children aged under 15 diagnosed with cancer between 2006 and 2015, with follow-up potentially available to 31 December 2020. The events of interest were relapse following remission, progressive disease, diagnosis of a second primary cancer or death from any cause. Five-year EFS and all-cause observed survival were both calculated, stratified by type of childhood cancer, remoteness of residence and stage at diagnosis. Differences in EFS were assessed using multivariable flexible parametric models.

RESULTS

Approximately one quarter of patients (n = 1605 of 7067, 23%) experienced at least one of the events of interest within 5 years of diagnosis. Relapse was twice as common for children with metastatic/advanced disease (22%) versus children with localised/limited cancers (11%). Overall 5-year EFS was 75.0% (95% confidence interval [CI]: 73.9%-76.0%), compared to 85.8% observed survival (95% CI: 85.0%-86.6%). Patients with other gliomas had the lowest EFS (35.4%, 95% CI: 27.8%-43.1%). EFS was significantly lower among children with acute myeloid leukaemia in outer regional/remote areas compared to major cities (adjusted hazard ratio [HR] = 1.90, 95% CI: 1.20-3.00).

CONCLUSIONS

Reporting EFS at a population level provides further insight on a wider range of impacts apart from mortality alone, contributing towards efforts to improve the management and outcomes of childhood cancer.

Off-label prescribing of immune checkpoint inhibitor therapy at a single pediatric cancer center

BACKGROUND

Immune checkpoint inhibitors (ICI) have improved outcomes in a variety of adult cancers and are prescribed with increasing frequency across oncology. However, patterns of off-label use of ICI in pediatrics remain unclear.

METHODS

This is a single-institution, retrospective cohort study evaluating off-label ICI use in pediatric and young adult patients with cancer treated at our institution from 2014 to 2022. Response was based on clinician assessment derived from clinical records. Immune-related adverse events (iRAEs) were classified according to CTCAE v5.0.

RESULTS

We identified 50 unique patients treated with off-label ICI (28 with solid tumors, 20 with central nervous system (CNS) tumors, 2 with hematologic malignancies). At time of ICI initiation, only five patients (10%) had localized disease, and all but one patient was treated in the relapsed/refractory setting. All patients were treated with the FDA-approved weight-based dosing recommendations. Overall, there was disease control in 21 patients (42%), with best response including one complete response (melanoma), two partial responses (high-grade glioma, CNS nongerminomatous germ cell tumor), and 18 patients with stable disease. Forty-four patients (88%) eventually experienced disease progression. Among 22 patients (44%) experiencing iRAEs, 10 (20%) had a grade ≥3 irAE, 12 (24%) required corticosteroids, and 14 (28%) required ICI discontinuation. irAE occurrence was associated with significantly improved progression-free survival (HR 0.35; 95% CI: 0.18 to 0.68; p = 0.002) and overall survival (HR 0.33; 95% CI: 0.17 to 0.66; p = 0.002).

CONCLUSIONS

At our institution, ICI was most commonly prescribed in the relapsed/refractory setting to patients with metastatic disease. The treatment was generally well-tolerated in the pediatric population. The overall response rate was low, and the majority of patients eventually experienced disease progression. A few patients, however, had durable treatment responses. Further studies are needed to identify which pediatric patients are most likely to benefit from ICI.

Addressing a Pre-Clinical Pipeline Gap: Development of the Pediatric Acute Myeloid Leukemia Patient-Derived Xenograft Program at Texas Children's Hospital at Baylor College of Medicine

The survival rate of pediatric acute myeloid leukemia (pAML) is currently around 60%. While survival has slowly increased over the past few decades, the development of novel agents likely to further improve survival for this heterogeneous patient population has been limited by gaps in the pAML pre-clinical pipeline. One of the major hurdles in evaluating new agents for pAML is the lack of pAML patient-derived xenograft (PDX) models. Unlike solid tumors and other types of leukemias, AML is notoriously hard to establish in mouse models, likely due in part to the need for specific human microenvironment elements. Our laboratory at TCH/BCM addressed this gap by establishing a systematic PDX workflow, leveraging advanced immunodeficient hosts and capitalizing on our high volume of pAML patients and close coordination between labs and clinical sections. Patients treated at TCH are offered the chance to participate in specimen banking protocols that allow blood and bone marrow collection as well as the collection of relevant clinical data. All patients who consent and have samples available are trialed for PDX development. In addition, samples from the Children's Oncology Group (COG) are also trialed for PDX generation. Serially transplanting PDX models are validated using short tandem repeat (STR) and characterized using both targeted DNA/RNA next generation sequencing and RNAseq. As of March 2023, this systematic approach has resulted in 26 serially transplanting models. Models have been shared with requesting labs to facilitate external pAML pre-clinical studies. Available PDX models can be located through the BCM PDX Portal. We expect our growing PDX resource to make a significant contribution to expediting the testing of promising novel therapeutics for pAML.

Linguistic analysis of plain language summaries and corresponding scientific summaries of Cochrane systematic reviews about oncology interventions

BACKGROUND

Cochrane plain language summaries (PLSs) are an important format to present high-quality healthcare evidence to patients with cancer and their families. They should be written in a way everyone can understand, since they serve as a tool in decision-making and present a bridge to overcome the gap between the healthcare users and professionals.

OBJECTIVE

The aim of the study was to assess the language characteristics of PLSs of Cochrane systematic reviews of oncology interventions in comparison with corresponding Cochrane scientific abstracts (SAs).

METHODS

In this cross-sectional study, we included all Cochrane PLSs and SAs of systematic reviews of oncology interventions available in the Cochrane Database of Systematic Reviews. We assessed text readability, measured using the Simple Measure of Gobbledygook (SMOG) index, and the prevalence of words related to different language tones (clout, authenticity, emotions and analytical tones). Two independent assessors categorized the conclusiveness of the efficacy of interventions into nine categories.

RESULTS

The overall median SMOG index for 275 PLSs was 13.0 (95% confidence interval [CI] 12.8-13.3). Readability scores did not differ across Cochrane Review Groups. SAs had a higher readability index than the corresponding PLSs (median = 16.6, 95% CI = 16.4-16.8). Regarding linguistic characteristics, PLSs were shorter than SAs, with less use of analytical tone, but more use of a positive emotional tone and authenticity. Overall, the 'Unclear' category of conclusiveness was the most common among all PLSs. Also, PLSs with 'No evidence' conclusions were the shortest and had the lowest SMOG index.

CONCLUSION

PLSs of Cochrane systematic reviews of oncological interventions have low readability and most give unclear conclusions about the efficacy of interventions. PLSs should be simplified so that patients and their families can benefit from appropriate health information on evidence synthesis. Further research is needed into reasons for unclear language to describe evidence from oncology trials.

[Application of "kindergarten effect" in radiotherapy for children with tumor aged 3-5 years]

OBJECTIVES

To study the clinical application effect of "kindergarten effect" in radiotherapy for children with tumor based on the psychology of preschool children aged 3-5 years.

METHODS

A total of 30 children, aged 3-5 years, who were admitted to the Department of Radiotherapy, Tianjin Medical University Cancer Institute and Hospital, from January 2020 to August 2021 were enrolled in this prospective study. The children were randomly divided into a control group and a test group, with 15 children in each group. The children in the test group were treated in "kindergarten mode", i.e., all children were treated together at a specified time and left together after all children completed treatment. Those in the control group were treated alternately with adult patients according to the treatment time based on the type of radiotherapy fixation device. The treatment compliance was evaluated for both groups, and the two groups were compared in terms of the setup errors in the superior-inferior (SI), left-right (LR), and anterior-posterior (AP) directions.

RESULTS

Compared with the control group, the test group showed a significantly shorter time for finishing the treatment (P<0.05) and a significantly lower proportion of children with treatment interruption (P<0.05). Compared with the control group, the test group showed smaller mean errors in the SI, LR and AP directions after image-guided radiotherapy, with significant differences in the mean errors in the SI and LR directions (P<0.05).

CONCLUSIONS

With the application of the "kindergarten effect", most children can actively cooperate in radiotherapy, and it can also improve the accuracy and repeatability of positioning and help to achieve the desired treatment outcome.

Exploration of Potential Ewing Sarcoma Drugs from FDA-Approved Pharmaceuticals through Computational Drug Repositioning, Pharmacogenomics, Molecular Docking, and MD Simulation Studies

Novel drug development is a time-consuming process with relatively high debilitating costs. To overcome this problem, computational drug repositioning approaches are being used to predict the possible therapeutic scaffolds against different diseases. In the current study, computational drug repositioning approaches were employed to fetch the promising drugs from the pool of FDA-approved drugs against Ewing sarcoma. The binding interaction patterns and conformational behaviors of screened drugs within the active region of Ewing sarcoma protein (EWS) were confirmed through molecular docking profiles. Furthermore, pharmacogenomics analysis was employed to check the possible associations of selected drugs with Ewing sarcoma genes. Moreover, the stability behavior of selected docked complexes (drugs-EWS) was checked by molecular dynamics simulations. Taken together, astemizole, sulfinpyrazone, and pranlukast exhibited a result comparable to pazopanib and can be used as a possible therapeutic agent in the treatment of Ewing sarcoma.

An ex vivo organ culture screening model revealed that low temperature conditions prevent side effects of anticancer drugs

Development of chemotherapy has led to a high survival rate of cancer patients; however, the severe side effects of anticancer drugs, including organ hypoplasia, persist. To assume the side effect of anticancer drugs, we established a new ex vivo screening model and described a method for suppressing side effects. Cyclophosphamide (CPA) is a commonly used anticancer drug and causes severe side effects in developing organs with intensive proliferation, including the teeth and hair. Using the organ culture model, we found that treatment with CPA disturbed the growth of tooth germs by inducing DNA damage, apoptosis and suppressing cellular proliferation and differentiation. Furthermore, low temperature suppressed CPA-mediated inhibition of organ development. Our ex vivo and in vitro analysis revealed that low temperature impeded Rb phosphorylation and caused cell cycle arrest at the G1 phase during CPA treatment. This can prevent the CPA-mediated cell damage of DNA replication caused by the cross-linking reaction of CPA. Our findings suggest that the side effects of anticancer drugs on organ development can be avoided by maintaining the internal environment under low temperature.

Childhood cancer drugs in China: An overview and comparison of regulatory approvals in China and the United States

Different from less developed countries, 80% of children with cancers in the United States are cured. Traditional chemotherapy drugs are the mainstay of therapies; new targeted medications have become available recently. Using publicly available data, we created a database of cancer drugs with paediatric malignancy indications approved by 31 October 2020 in China and the United States. We compared numbers, type, indications and listing on the World Health Organization Model List of Essential Medicines for Children (WHO EMLc) between the two countries, assessed the correlation between paediatric indications and cancer incidences, and described evidence supporting approvals of targeted medications in the two settings. Our study showed that by 31 October 2020, 31 and 39 cancer drugs available in China and the United States were approved for use in children, corresponding to 137 and 102 paediatric cancer indications, respectively. About half of these drugs (17 in China and 18 in the United States) were listed on the WHO EMLc. The correlation between indications and burden of disease was higher in the United States (r = 0.68) than China (r = 0.59). More traditional chemotherapy drugs were approved in China (n = 27) than the United States (n = 19). Of 20 targeted childhood anticancer medicines approved in the United States, mainly on the basis of single arm trials (27/32 indications, 84.4%), only four were approved for paediatric indications in China, at a median of 2.8 years after US Food and Drug Administration approval. A harmonised, evidence-based regulatory framework is needed to ensure approvals of needed, safe and efficacious childhood cancer drugs across the world.

Life after Cell Death-Survival and Survivorship Following Chemotherapy

Simple Summary

Treatment of aggressive cancers often relies on chemotherapy. This treatment has improved survival rates, but while effective at killing cancer cells, inevitably it also kills or alters the function of others. While many of the known effects are transient and resolve after treatment, as survival rates increase, so does our understanding of the long-term health costs that accompany cancer survivors. Here we provide an overview of common long-term morbidities known to be caused by conventional chemotherapy, including the risk of relapse, but more importantly, the cost of quality of life experienced, especially by those who have cancer in early life. We aim to highlight the importance of the development of targeted therapies to replace the use of conventional chemotherapy, but also that of treating the patients along with the disease to enable not only longer but also healthier life after cancer.

Abstract

To prevent cancer cells replacing and outnumbering their functional somatic counterparts, the most effective solution is their removal. Classical treatments rely on surgical excision, chemical or physical damage to the cancer cells by conventional interventions such as chemo- and radiotherapy, to eliminate or reduce tumour burden. Cancer treatment has in the last two decades seen the advent of increasingly sophisticated therapeutic regimens aimed at selectively targeting cancer cells whilst sparing the remaining cells from severe loss of viability or function. These include small molecule inhibitors, monoclonal antibodies and a myriad of compounds that affect metabolism, angiogenesis or immunotherapy. Our increased knowledge of specific cancer types, stratified diagnoses, genetic and molecular profiling, and more refined treatment practices have improved overall survival in a significant number of patients. Increased survival, however, has also increased the incidence of associated challenges of chemotherapy-induced morbidity, with some pathologies developing several years after termination of treatment. Long-term care of cancer survivors must therefore become a focus in itself, such that along with prolonging life expectancy, treatments allow for improved quality of life.

Developing New Agents for Treatment of Childhood Cancer: Challenges and Opportunities for Preclinical Testing

Developing new therapeutics for the treatment of childhood cancer has challenges not usually associated with adult malignancies. Firstly, childhood cancer is rare, with approximately 12,500 new diagnoses annually in the U.S. in children 18 years or younger. With current multimodality treatments, the 5-year event-free survival exceeds 80%, and 70% of patients achieve long-term “cure”, hence the overall number of patients eligible for experimental drugs is small. Childhood cancer comprises many disease entities, the most frequent being acute lymphoblastic leukemias (25% of cancers) and brain tumors (21%), and each of these comprises multiple molecular subtypes. Hence, the numbers of diagnoses even for the more frequently occurring cancers of childhood are small, and undertaking clinical trials remains a significant challenge. Consequently, development of preclinical models that accurately represent each molecular entity can be valuable in identifying those agents or combinations that warrant clinical evaluation. Further, new regulations under the Research to Accelerate Cures and Equity for Children Act (RACE For Children Act) will change the way in which drugs are developed. Here, we will consider some of the limitations of preclinical models and consider approaches that may improve their ability to translate therapy to clinical trial more accurately.

Oral mucositis in childhood cancer patients receiving high-dose methotrexate: Prevalence, relationship with other toxicities and methotrexate elimination

BACKGROUND

Oral mucositis (OM) is one of the main adverse effects of the chemotherapeutic agent methotrexate (MTX).

AIM

To evaluate the relationship of OM with MTX metabolism time and other toxicities in childhood, cancer patients receiving high-dose of methotrexate (HD-MTX).

DESIGN

Seventy-seven childhood patients receiving HD-MTX for treatment of leukaemia, osteosarcoma or lymphoma were evaluated. MTX serum level, hepatic and renal function parameters, and presence and intensity of OM were analysed.

RESULTS

The patients were submitted to 255 cycles of chemotherapy. OM was diagnosed in 191 (74.9%) cycles. Of these, 119 (46.6%) presented ulcerative lesions. Lymphoma was associated with severe OM (P = .01). OM was associated with higher serum levels of aspartate aminotransferase (P = .006), alanine aminotransferase (P = .04) and creatinine (P = .008). Increase of one unit of total bilirubin and indirect bilirubin associated, respectively, with 11% and 39% higher prevalence of OM. For each increase of one unit of creatinine serum level, it was observed a 37% higher prevalence of OM in patients with lymphoma. No association was found between delayed excretion of MTX and OM development.

CONCLUSIONS

OM is a prevalent complication of childhood cancer patients receiving HD-MTX. Renal and hepatic toxicity could be considered risk factors for OM, especially in patients with lymphoma.

Hypoxia and its therapeutic possibilities in paediatric cancers

In tumours, hypoxia-a condition in which the demand for oxygen is higher than its availability-is well known to be associated with reduced sensitivity to radiotherapy and chemotherapy, and with immunosuppression. The consequences of hypoxia on tumour biology and patient outcomes have therefore led to the investigation of strategies that can alleviate hypoxia in cancer cells, with the aim of sensitising cells to treatments. An alternative therapeutic approach involves the design of prodrugs that are activated by hypoxic cells. Increasing evidence indicates that hypoxia is not just clinically significant in adult cancers but also in paediatric cancers. We evaluate relevant methods to assess the levels and extent of hypoxia in childhood cancers, including novel imaging strategies such as oxygen-enhanced magnetic resonance imaging (MRI). Preclinical and clinical evidence largely supports the use of hypoxia-targeting drugs in children, and we describe the critical need to identify robust predictive biomarkers for the use of such drugs in future paediatric clinical trials. Ultimately, a more personalised approach to treatment that includes targeting hypoxic tumour cells might improve outcomes in subgroups of paediatric cancer patients.

PCAT: an integrated portal for genomic and preclinical testing data of pediatric cancer patient-derived xenograft models

Although cancer is the leading cause of disease-related mortality in children, the relative rarity of pediatric cancers poses a significant challenge for developing novel therapeutics to further improve prognosis. Patient-derived xenograft (PDX) models, which are usually developed from high-risk tumors, are a useful platform to study molecular driver events, identify biomarkers and prioritize therapeutic agents. Here, we develop PDX for Childhood Cancer Therapeutics (PCAT), a new integrated portal for pediatric cancer PDX models. Distinct from previously reported PDX portals, PCAT is focused on pediatric cancer models and provides intuitive interfaces for querying and data mining. The current release comprises 324 models and their associated clinical and genomic data, including gene expression, mutation and copy number alteration. Importantly, PCAT curates preclinical testing results for 68 models and 79 therapeutic agents manually collected from individual agent testing studies published since 2008. To facilitate comparisons of patterns between patient tumors and PDX models, PCAT curates clinical and molecular data of patient tumors from the TARGET project. In addition, PCAT provides access to gene fusions identified in nearly 1000 TARGET samples. PCAT was built using R-shiny and MySQL. The portal can be accessed at http://pcat.zhenglab.info or http://www.pedtranscriptome.org.

JP1 suppresses proliferation and metastasis of melanoma through MEK1/2 mediated NEDD4L-SP1-Integrin αvβ3 signaling

Background: JWA gene is known to down-regulate SP1 and reduces the expression level of Integrin αvβ3. Here, we identified a functional polypeptide (JP1) based on the active fragment of the JWA protein to suppress melanoma growth and metastasis by inhibiting the Integrin αvβ3. Methods: We conducted a series of melanoma growth and metastasis mouse models to evaluate anti-melanoma effect of JP1 peptide. 18F-labeled JP1 (18F-NFP-JP1) was detected by Micro-PET assay to demonstrate drug biodistribution. Toxicity test in cynomolgus monkeys and pharmacokinetic studies in rats were done to assess the druggability. The expression of MEK1/2, NEDD4L, SP1 and Integrin αvβ3 were detected in vitro and vivo models. Results: The peptide JP1 with the best anticancer effect was obtained. Micro-PET assay showed that JP1 specifically targeting to melanoma cells in vivo. JP1 inhibited melanoma growth, metastasis, and prolonged the survival of mouse. JP1 reduced the dosage and toxicity in combination with DTIC in melanoma xenograft and allograft mouse models. Cynomolgus monkey toxicity test showed no observed adverse effect level (NOAEL) of JP1 was 150 mg/kg. Mechanistically, JP1 was shown to activate p-MEK1/2 and triggered SP1 ubiquitination in melanoma cells. NEDD4L, an E3 ubiquitin ligase, was activated by p-MEK1/2 and to ubiquitinate SP1 at K685 site, resulting in subsequent degradation. Conclusions: JP1 was developed as a novel peptide that indicated therapeutic roles on proliferation and metastasis of melanoma through the NEDD4L-SP1-Integrin αvβ3 signaling.