Removing barriers to accessing medical cannabis for paediatric patients.

Medical cannabis (MC) may offer therapeutic benefits for children with complex neurological conditions and chronic diseases. In Canada, parents, and caregivers frequently report encountering barriers when accessing MC for their children. These include negative preconceived notions about risks and benefits, challenges connecting with a knowledgeable healthcare provider (HCP), the high cost of MC products, and navigating MC product shortages. In this manuscript, we explore several of these barriers and provide recommendations to decision-makers to enable a family-centered and evidence-based approach to MC medicine and research for children.

Systematic Critical Review of Genetic Factors Associated with Cisplatin-induced Ototoxicity: Canadian Pharmacogenomics Network for Drug Safety 2022 Update.

BACKGROUND: Cisplatin is commonly used to treat solid tumors; however, its use can be complicated by drug-induced hearing loss (ie, ototoxicity). The presence of certain genetic variants has been associated with the development/occurrence of cisplatin-induced ototoxicity, suggesting that genetic factors may be able to predict patients who are more likely to develop ototoxicity. The authors aimed to review genetic associations with cisplatin-induced ototoxicity and discuss their clinical relevance. METHODS: An updated systematic review was conducted on behalf of the Canadian Pharmacogenomics Network for Drug Safety, based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 statement. Pharmacogenomic studies that reported associations between genetic variation and cisplatin-induced ototoxicity were included. The evidence on genetic associations was summarized and evaluated, and knowledge gaps that can be used to inform future pharmacogenomic studies identified. RESULTS: Overall, 40 evaluated reports, considering 47 independent patient populations, captured associations involving 24 genes. Considering GRADE criteria, genetic variants in 2 genes were strongly (ie, odds ratios ≥3) and consistently (ie, replication in ≥3 independent populations) predictive of cisplatin-induced ototoxicity. Specifically, an ACYP2 variant has been associated with ototoxicity in both children and adults, whereas TPMT variants are relevant in children. Encouraging evidence for associations involving several other genes also exists; however, further research is necessary to determine potential clinical relevance. CONCLUSIONS: Genetic variation in ACYP2 and TPMT may be helpful in predicting patients at the highest risk of developing cisplatin-induced ototoxicity. Further research (including replication studies considering diverse pediatric and adult patient populations) is required to determine whether genetic variation in additional genes may help further identify patients most at risk.

Cannabinoids for symptom management in children with cancer: A systematic review and meta-analysis.

BACKGROUND: Despite the widespread use of medical cannabis, little is known regarding the safety, efficacy, and dosing of cannabis products in children with cancer. The objective of this study was to systematically appraise the existing published literature for the use of cannabis products in children with cancer. METHODS: This systematic review, registered with the International Prospective Register of Systematic Reviews (CRD42020187433), searched four databases: MEDLINE, Embase, PsycINFO, and the Cochrane Library. Abstracts and full texts were screened in duplicate. Data on types of cannabis products, doses, formulations, frequencies, routes of administration, indications, and clinical and demographic details as well as reported efficacy outcomes were extracted. Data on cannabinoid-related adverse events were also summarized. RESULTS: Out of 34,611 identified citations, 19 unique studies with a total of 1927 participants with cancer were included: eight retrospective chart reviews, seven randomized controlled trials, two open-label studies, and two case reports. The included studies reported the use of various cannabis products for the management of symptoms. Cannabinoids were commonly used for the management of chemotherapy-induced nausea and vomiting (11 of 19 [58%]). In controlled studies, somnolence, dizziness, dry mouth, and withdrawal due to adverse events were more commonly associated with the use of cannabinoids. Across all included studies, no serious cannabis-related adverse events were reported. CONCLUSIONS: Although there is evidence to support the use of cannabis for symptom management, in children with cancer, there is a lack of rigorous evidence to inform the dosing, safety, and efficacy of cannabinoids. Because of the increasing interest in using cannabis, there is an urgent need for more research on medical cannabis in children with cancer.

Gene-based drug therapy in children.

The past two decades have seen enormous advancements in medical knowledge around the role of genetic factors of variability, both in human disease and drug response. This knowledge is increasingly being translated into guidelines that inform drug dosing, monitoring for efficacy and safety, and determining the suitability of specific agents to treat patients. Health Canada and the U.S. Food and Drug Administration have recommended using genetic information to guide dosing for more than 20 drugs. There are no current, comprehensive paediatric guidelines to assist health care professionals in the use of genetics to inform medication dosing, safety, and efficacy in children, and such guidance is urgently needed. This statement helps to guide clinician understanding of the role of pharmacogenetics and how to use this information when prescribing medications in paediatrics.

La pharmacothérapie en fonction des gènes.

Depuis vingt ans, le savoir médical sur le rôle des facteurs génétiques de variabilité a énormément évolué, tant à l'égard des maladies humaines que de la réponse aux médicaments. Ce savoir se traduit de plus en plus par des directives qui influent sur la posologie, la surveillance de l'efficacité et de l'innocuité et la détermination de la pertinence d'agents particuliers pour traiter les patients. Santé Canada et la Food and Drug Administration des États-Unis recommandent d'utiliser l'information génétique pour orienter la posologie de plus de 20 médicaments. Il n'existe actuellement pas de directives pédiatriques complètes pour aider les professionnels de la santé à utiliser la génétique afin d'établir la posologie, l'innocuité et l'efficacité des médicaments chez les enfants, et ces directives s'imposent d'urgence. Le présent document de principes aide le clinicien à comprendre le rôle de la pharmacogénétique et à utiliser l'information qu'il en tire pour prescrire des médicaments en pédiatrie.

Outcomes of a radiation sparing approach in medulloblastoma by subgroup in young children: an institutional review.

OBJECTIVE: To describe disease outcomes including overall survival and relapse patterns by subgroup in young pediatric patients treated for medulloblastoma with a radiation-sparing approach. METHODS: Retrospective analysis of clinical outcomes includes treatment, relapse, and salvage therapy and late effects in children treated for medulloblastoma with a radiation-sparing approach at British Columbia Children's Hospital (BCCH) between 2000 and 2020. RESULTS: There were 30 patients (median age 2.8 years, 60% male) treated for medulloblastoma with a radiation-sparing approach at BCCH. Subgroups included Sonic Hedgehog (SHH) (n = 14), group 3 (n = 7), group 4 (n = 6), and indeterminate status (n = 3). Three- and 5-year event-free survival (EFS) were 49.0% (30.2-65.4%) and 42.0% (24.2-58.9%) and overall survival (OS) 66.0% (95% CI 46.0-80.1%) and 62.5% (95% CI 42.5 and 77.2%), respectively, with a median follow-up of 9.5 years. Relapse occurred in 12/25 patients following a complete response, of whom six (group 4: n = 4; group 3: n = 1; unknown: n = 1) were successfully salvaged with craniospinal axis (CSA) RT and remain alive at a median follow-up of 7 years. Disease/treatment-related morbidity included endocrinopathies (n = 8), hearing loss n = 16), and neurocognitive abnormalities (n = 9). CONCLUSIONS: This radiation sparing treatment approach for young patients with medulloblastoma resulted in a durable cure in most patients with SHH subgroup medulloblastoma. In those patients with groups 3 and 4 medulloblastoma, relapse rates were high; however, most group 4 patients were salvaged with RT.

Role of Cisplatin Dose Intensity and TPMT Variation in the Development of Hearing Loss in Children.

BACKGROUND: Cisplatin, widely used in the treatment of solid tumors, causes permanent hearing loss in more than 60% of treated children. Previous studies have implicated several clinical factors in the development of ototoxicity, including cumulative cisplatin dose. However, the role of cisplatin dose intensity in the development of hearing loss in children remains unclear. Pharmacogenetic studies have also identified genetic variants in TPMT that increase the risk of cisplatin-induced hearing loss. This study aims to determine whether cisplatin dose intensity contributes to the risk of hearing loss in children and whether genetic variations in TPMT further modifies the risk of cisplatin-induced hearing loss. METHODS: The authors genotyped 371 cisplatin-treated children for the presence of any 3 TPMT -risk variants. Patients were categorized into high-, moderate-, and low-intensity cisplatin dosing groups according to the cisplatin dose administered per unit time. Kaplan-Meier curves were plotted to compare the cumulative incidence of hearing loss between the genotype and dose intensity groups. RESULTS: Patients receiving cisplatin at high dose intensity experienced significantly higher incidences of ototoxicity than those receiving cisplatin at low dose intensity ( P = 9 × 10 -7 ). Further stratification by TPMT genotype revealed that carriers of ≥1 TPMT variants receiving high-intensity cisplatin developed ototoxicity sooner and more often than their wild-type counterparts (93.8% vs. 56.6% at 12 months; P = 5 × 10 -5 ) and noncarriers receiving low-intensity cisplatin (21.2% at 12 months). CONCLUSIONS: Cisplatin dose intensity is strongly associated with ototoxicity development in children, and this risk is further increased by the presence of TPMT -risk alleles.

A Systematic Review of Polygenic Models for Predicting Drug Outcomes.

Polygenic models have emerged as promising prediction tools for the prediction of complex traits. Currently, the majority of polygenic models are developed in the context of predicting disease risk, but polygenic models may also prove useful in predicting drug outcomes. This study sought to understand how polygenic models incorporating pharmacogenetic variants are being used in the prediction of drug outcomes. A systematic review was conducted with the aim of gaining insights into the methods used to construct polygenic models, as well as their performance in drug outcome prediction. The search uncovered 89 papers that incorporated pharmacogenetic variants in the development of polygenic models. It was found that the most common polygenic models were constructed for drug dosing predictions in anticoagulant therapies (n = 27). While nearly all studies found a significant association with their polygenic model and the investigated drug outcome (93.3%), less than half (47.2%) compared the performance of the polygenic model against clinical predictors, and even fewer (40.4%) sought to validate model predictions in an independent cohort. Additionally, the heterogeneity of reported performance measures makes the comparison of models across studies challenging. These findings highlight key considerations for future work in developing polygenic models in pharmacogenomic research.

Clinician views on and ethics priorities for authorizing medical cannabis in the care of children and youth in Canada: a qualitative study.

BACKGROUND: The use of cannabis for medical purposes by pediatric patients is expanding across Canada; however, supporting evidence, federal regulations and treatment guidelines are lacking. To understand factors affecting treatment decisions in this landscape, we sought to delineate clinician perspectives, ethics priorities and values for cannabis authorization. METHODS: We sampled participants purposefully through Canadian Childhood Cannabinoid Clinical Trials listservs, which include the majority of pediatric oncologists and palliative care physicians practising in Canada, among many other pediatric physicians and clinicians. Inclusion criteria were being a practising clinician in Canada, involvement in the care of children and willingness to be interviewed regardless of stance on medical cannabis. In November and December 2020, we conducted semistructured interviews focusing on principles, values and priorities, including medical, professional, regulatory, evidentiary and social considerations, for authorizing medical cannabis to children. Interviews were recorded, transcribed and analyzed by means of deductive and inductive thematic methods. RESULTS: We conducted 18 interviews with a diverse group of clinicians representing a range of specialties within pediatric care, including neurology, palliative care, oncology, family medicine and pharmacology. The interviews yielded 4 themes and 12 subthemes related to a priori (medical, professional, regulatory, evidentiary and social themes) and emergent themes. The 4 themes of access, relationships and relational autonomy (autonomy within relationships), medically appropriate use and research priorities were grounded in principles of harm reduction. Participants described problematic authorization procedures that negatively affect patient use. Principles associated with relational autonomy were highlighted as a feature of open clinical communication. Benefits of appropriate medical uses weighed positively over risks, even in the context of potential effects on neurodevelopment. Participants expressed that more research is essential to align medical cannabis with biomedical standards. INTERPRETATION: Clinicians reported pursuing ethical use of medical cannabis for pediatric patients and prioritizing their safety under principles of harm reduction. There is a need for evidence about neurodevelopmental risks, support for research, treatment guidelines and greater knowledge about stakeholder perspectives to alleviate burdens related to use of medical cannabis for pediatric patients in Canada.

Medicinal cannabis in children and adolescents with autism spectrum disorder: A scoping review.

BACKGROUND: Autism spectrum disorder (ASD) is a neurodevelopmental condition estimated to affect 1 in 66 children in Canada and 1 in 270 individuals worldwide. As effective therapies for the management of ASD core and associated symptoms are limited, parents are increasingly turning to clinicians for advice regarding the use of medicinal cannabis to manage behavioural disturbances. OBJECTIVE: The objective of this scoping review was to identify and map symptoms, outcomes and adverse events related to medicinal cannabis treatment for ASD-related behaviours. METHODS: Ovid MEDLINE, Embase, CINAHL, PsycInfo, Web of Science Core Collection, Google Scholar and grey literature sources were searched up to 5 January 2020 for studies. Included studies met the following criteria: (1) investigate the use of medicinal cannabis, (2) at least 50% participants had ASD, (3) at least 50% of the study population was 0-18 years old and (4) any study design (published or unpublished). RESULTS: We identified eight completed and five ongoing studies meeting the inclusion criteria. All studies reported substantial behaviour and symptom improvement on medicinal cannabis, with 61% to 93% of subjects showing benefit. In the three studies reporting on concomitant psychotropic medication usage and with cannabis use, up to 80% of participants observed a reduction in concurrent medication use. Adverse events related to cannabis use were reported in up to 27% of participants related, and two participants had psychotic events. CONCLUSIONS: Early reports regarding medicinal cannabis in paediatric ASD symptom management are presented as positive; the evidence, however, is limited to very few retrospective cohort and observational studies. Evidence of safety and efficacy from prospective clinical trials is needed.

Malignant Mesothelioma With EWSR1-ATF1 Fusion in Two Adolescent Male Patients.

Malignant mesothelioma is a neoplasm of serosal surfaces, most commonly affecting the pleura. The peritoneum, pericardium, and tunica vaginalis are less frequently involved. Malignant mesothelioma with EWSR1-ATF1 fusion in young adults was recently reported in the literature. Here, we present two pediatric cases of EWSR1-ATF1 translocation-associated malignant mesothelioma in the peritoneum and pericardium respectively. Both cases lacked a known exposure history. Microscopy in both cases showed predominantly epithelioid morphology with ample eosinophilic cytoplasm, and immunohistochemistry was positive for pan-keratin, calretinin, and WT1. Both cases showed EWSR1-ATF1 gene rearrangement by RNA sequencing, which was instrumental in confirming the diagnosis of malignant mesothelioma and to exclude more common pediatric sarcomas, especially in the context of limited sampling.

Efficacy and safety of paediatric medicinal cannabis use: A scoping review.

INTRODUCTION: The use of medicinal cannabis in the paediatric age group is increasing despite the lack of evidence for its efficacy or safety. OBJECTIVE: To map the available evidence on the efficacy and safety of medicinal cannabis in children and adolescents. METHODS: We conducted a scoping review and searched six electronic databases and grey literature. A study was eligible for inclusion when it investigated the efficacy or safety of medicinal cannabis for any condition, more than half of the participants were 0 to 18 years old, and had any study design except single case reports. RESULTS: We included 36 studies in our final analysis, 32 of which investigated the efficacy or safety of cannabis in treatment-resistant epilepsy. The remaining 4 studies examined patients with cancer, dysautonomia, Epidermolysis Bullosa, and motor disorders. CONCLUSIONS: There is a lack of evidence on the efficacy and safety of medicinal cannabis in most paediatric conditions.

Deliberations about clinical pharmacogenetic testing in pediatric oncology.

This article summarizes the background, content and outcomes of a special meeting that was convened among oncologists and scientists to discuss the role of pharmacogenetic (PGx) testing in pediatric clinical oncology practice. This meeting provided an opportunity for what the lead author (AM Issa) refers to as the 'voice of the clinician' dynamic to be amplified in order to better understand how personalized or precision medicine applications such as PGx testing are adopted and incorporated into clinical settings and what we can learn from the experiences of current and ongoing implementation PGx approaches to further the implementation of precision medicine applications in real-world environments. Group dynamics and clinical experience with PGx testing and return of results shaped the discussion.

Establishing a Framework for the Clinical Translation of Germline Findings in Precision Oncology.

Inherited genetic variation has important implications for cancer screening, early diagnosis, and disease prognosis. A role for germline variation has also been described in shaping the molecular landscape, immune response, microenvironment, and treatment response of individual tumors. However, there is a lack of consensus on the handling and analysis of germline information that extends beyond known or suspected cancer susceptibility in large-scale cancer genomics initiatives. As part of the Personalized OncoGenomics program in British Columbia, we performed whole-genome and transcriptome sequencing in paired tumor and normal tissues from advanced cancer patients to characterize the molecular tumor landscape and identify putative targets for therapy. Overall, our experience supports a multidisciplinary and integrative approach to germline data management. This includes a need for broader definitions and standardized recommendations regarding primary and secondary germline findings in precision oncology. Here, we propose a framework for identifying, evaluating, and returning germline variants of potential clinical significance that may have indications for health management beyond cancer risk reduction or prevention in patients and their families.

Evaluating the quantity, quality and size distribution of cell-free DNA by multiplex droplet digital PCR.

Cell-free DNA (cfDNA) has become a comprehensive biomarker in the fields of non-invasive cancer detection and monitoring, organ transplantation, prenatal genetic testing and pathogen detection. While cfDNA samples can be obtained using a broad variety of approaches, there is an urgent need to standardize analytical tools aimed at assessing its basic properties. Typical methods to determine the yield and fragment size distribution of cfDNA samples are usually either blind to genomic DNA contamination or the presence of enzymatic inhibitors, which can confound and undermine downstream analyses. Here, we present a novel droplet digital PCR assay to identify suboptimal samples and aberrant cfDNA size distributions, the latter typically associated with high levels of circulating tumour DNA (ctDNA). Our assay was designed to promiscuously cross-amplify members of the human olfactory receptor (OR) gene family and includes a customizable diploid locus for the determination of absolute cfDNA concentrations. We demonstrate here the utility of our assay to estimate the yield and quality of cfDNA extracts and deduce fragment size distributions that correlate well with those inferred by capillary electrophoresis and high throughput sequencing. The assay described herein is a powerful tool to establish quality controls and stratify cfDNA samples based on presumed ctDNA levels, then facilitating the implementation of robust, cost-effective and standardized analytical workflows into clinical practice.

Waning Vaccine Immunity and Vaccination Responses in Children Treated for Acute Lymphoblastic Leukemia: A Canadian Immunization Research Network Study.

BACKGROUND: There is no uniform guideline for postchemotherapy vaccination of children with acute lymphoblastic leukemia (ALL). We evaluated waning immunity to 14 pneumococcal serotypes, pertussis toxin (PT), tetanus toxoid (TT) and varicella, and immunogenicity of postchemotherapy diphtheria, tetanus, pertussis, hepatitis B, polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) and pneumococcal vaccination among previously vaccinated children treated for ALL. METHODS: This was a multicenter trial of children with ALL enrolled 4-12 months postchemotherapy completion. Exclusion criteria included: infant ALL, relapsed ALL, and stem cell transplant recipients. Immunocompetent children were recruited as controls. Postchemotherapy participants received DTaP-IPV-Hib and 13-valent pneumococcal conjugate vaccine (PCV13) concurrently, followed by 23-valent pneumococcal polysaccharide vaccine (PPV23) 2 months later. Serology was measured at baseline, 2 and 12 months postvaccination. Adverse events were captured via surveys. RESULTS: At enrollment, postchemotherapy participants (n = 74) were less likely than controls (n = 78) to be age-appropriately immunized with DTaP (41% vs 89%, P < .001) and PCV (59% vs 79%, P = .008). Geometric mean concentrations (GMCs) to TT, PT, PCV serotypes, and varicella were lower in postchemotherapy participants than controls after adjusting for previous vaccine doses (P < .001). Two months postvaccination, GMCs to TT, PT, and PCV serotypes increased from baseline (P < .001 for all antigens) and remained elevated at 12 months postvaccination. Antibody levels to PPV23 serotypes also increased postvaccination (P < .001). No serious adverse events were reported. CONCLUSIONS: Children treated for ALL had lower antibody levels than controls against pneumococcal serotypes, tetanus, pertussis, and varicella despite previous vaccination. Postchemotherapy vaccination with DTaP-IPV-Hib, PCV13, and PPV23 was immunogenic and well tolerated. Children with ALL would benefit from systematic revaccination postchemotherapy. CLINICAL TRIALS REGISTRATION: NCT02447718.