Impact of dexamethasone on transplant-related mortality in pediatric patients: a multi-site, propensity score-weighted, retrospective assessment.

Dexamethasone use during hematopoietic cell transplant (HCT) conditioning varies between pediatric centers. This study aimed to estimate the difference in 1-year treatment-related mortality (TRM) between patients who did or did not receive dexamethasone during HCT conditioning. Secondary objectives were to estimate the difference between dexamethasone-exposed and dexamethasone-unexposed groups in 1-year event-free survival (EFS), time to neutrophil engraftment, acute graft-versus-host disease (aGVHD), and invasive fungal disease (IFD) at day + 100. This was a seven-site, international, retrospective cohort study. Patients < 18 years old undergoing their first allogeneic or autologous myeloablative HCT for hematologic malignancy or aplastic anemia between January 1, 2012, and July 31, 2017, were included. To control for potential confounders, propensity score weighting was used to calculate the standardized mean difference for all endpoints. Among 242 patients, 140 received dexamethasone during HCT conditioning and 102 did not. TRM was unaffected by dexamethasone exposure (1.7%; 95% CI - 7.4, 10.2%). Between-group differences in secondary outcomes were small. However, dexamethasone exposure significantly increased possible, probable, and proven IFD incidence (9.0%, 95% CI 0.8, 17.3%). TRM is not increased in pediatric patients who receive dexamethasone during HCT conditioning. Clinicians should consider potential IFD risk when selecting chemotherapy-induced vomiting prophylaxis for pediatric HCT patients.

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.

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.

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.

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.

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.

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.

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.

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.

Phase I study of vinblastine and temsirolimus in pediatric patients with recurrent or refractory solid tumors: Canadian Cancer Trials Group Study IND.218.

Combining mammalian target of rapamycin (mTOR) inhibitors and vinca alkaloids has shown therapeutic synergy in xenograft models of pediatric cancers. This phase I study assessed safety and toxicity of temsirolimus in combination with vinblastine in children. PROCEDURE: Patients ≥ 1 and ≤ 18 years with recurrent/refractory solid or CNS tumors were eligible. Vinblastine (4 mg/m2 ) and temsirolimus (15 mg/m2 ) were administered i.v. weekly, with planned dose escalation of vinblastine using a rolling six phase I design. Pharmacokinetic and pharmacodynamic data were collected. RESULTS: Seven patients with median age 12 years (range, 8-18 years) were enrolled; all were evaluable for toxicity and six for response. At dose level 1, four of six patients developed grade 3 mucositis, of which one met duration criteria for dose-limiting toxicity (DLT). Four patients required dose omissions for grade 3 or 4 hematologic toxicity, including one prolonged neutropenia DLT. A subsequent patient was enrolled on dose level -2 (temsirolimus 10 mg/m2 , vinblastine 4 mg/m2 ) with no protocol-related toxicity > grade 1, except grade 2 neutropenia. Two serious adverse events (SAE) occurred-an allergic reaction to temsirolimus (grade 2) and an intracranial hemorrhage in a CNS tumor patient (grade 3)-unlikely related to study therapy. Soluble VEGFR2 was reduced at cycle 1, day 36 in keeping with inhibition of angiogenesis. Four patients achieved prolonged stable disease for a median of 5.0 months (range, 3.1-8.3 months). CONCLUSION: The combination of weekly temsirolimus (15 mg/m2 ) and vinblastine (4 mg/m2 ) exceeds the maximum tolerated dose in children, with frequent oral mucositis and hematologic toxicity.

Intra-arterial methylprednisolone for severe steroid refractory gastrointestinal graft-versus-host disease.

Acute graft versus host disease (GVHD) is a significant complication of bone marrow transplantation with approximately half of patients being refractory to steroids. There are numerous second-line systemic immunosuppressive treatments but the overall prognosis is poor and these therapies are associated with high mortality due to infection. An alternative approach to systemic treatment for GVHD is targeted delivery of immunosuppression. We present two pediatric cases with steroid-refractory gastrointestinal GVHD who clinically responded to intra-arterial steroid administration. We also review the literature regarding this treatment modality with a particular emphasis in children.

VKORC1 and CYP2C9 genotypes are predictors of warfarin-related outcomes in children.

BACKGROUND: Despite substantial evidence supporting a pharmacogenetic approach to warfarin therapy in adults, evidence on the importance of genetics in warfarin therapy in children is limited, particularly for clinical outcomes. We assessed the contribution of CYP2C9/VKORC1/CYP4F2 genotypes and variation in other genes involved in vitamin K and coagulation pathways to warfarin dose and related clinical outcomes in children. PROCEDURE: Clinical and genetic data for 93 children (age ≤ 18 years) who received warfarin therapy were obtained. DNA was genotyped for 93 selected single nucleotide polymorphisms using a custom assay. RESULTS: With a median age of 4.8 years, our cohort included more young children than most previous studies. Overall, 76.3% of dose variability was explained by weight, indication, VKORC1-1639G/A and CYP2C9 *2/*3, with genotypes accounting for 21.1% of variability. There was a strong correlation (R(2) = 0.68; P < 0.001) between actual and predicted warfarin dose using a pediatric genotype-based dosing model. VKORC1 genotype had a significant impact on time to therapeutic international normalized ratio (INR) (P = 0.047) and time to over-anticoagulation (INR > 4; P = 0.024) during the initiation of therapy. CYP2C9*3 carriers were also at increased risk of major bleeding while receiving warfarin (adjusted OR = 11.28). An additional variant in CYP2C9 (rs7089580) was significantly associated with warfarin dose (P = 0.020) in a multivariate clinical and genetic model. CONCLUSIONS: This study confirms the importance of VKORC1/CYP2C9 genotypes for warfarin dosing in a young pediatric cohort and demonstrates an impact of genetic factors on clinical outcomes in children. Furthermore, we identified an additional variant in CYP2C9 of potential relevance for warfarin dosing in children.

True Rate of Allergy among Pediatric Inpatients with Penicillin Allergy Labels (TRIAL).

Background: Penicillin allergy is a common drug allergy diagnosis in pediatric patients; however, upon appropriate allergy testing, many of these patients are found not to have a true allergy. For patients with a reported allergy, alternative antibiotics are prescribed, which are less effective, more toxic, or more expensive. There is a lack of data evaluating allergies in hospitalized children and comparing allergy assessments conducted by pediatric allergists and pharmacists. Objective: To estimate the percentage of pediatric patients admitted with reported penicillin allergy who did not have a true penicillin allergy. Methods: This single-centre prospective cohort study included inpatients between 6 months and 17 years of age, with a documented penicillin allergy, who were admitted to the general pediatric and oncology units of a tertiary care children's hospital between November 2019 and March 2023. The allergy history, evaluation, and risk categorization were performed by pharmacists. The history was reviewed with the allergist, and the patient was then referred, underwent skin testing, or received oral amoxicillin challenge with monitoring for 1 hour. Results: Thirty patients were included, of whom 29 (97%) had delabelling of their penicillin allergy. Four patients (13%) had delabelling on the basis of history alone, without risk assessment. Twenty-five (83%) of the patients were assessed as having low risk; 24 of these had delabelling following oral challenge, and 1 did not complete the oral challenge because of transfer to another hospital. One patient (3%) was assessed as having moderate risk, with delabelling on the basis of results of skin testing and oral challenge. The pharmacist's and allergist's risk assessments were in agreement in 29 (97%) of the 30 cases. Conclusions: Pediatric patients, including those with oncologic malignancies, are often mislabelled as having a penicillin allergy. Pharmacists are able to accurately determine true allergy risk and delabel penicillin allergies for pediatric patients in the hospital setting.

Contexte: L'allergie à la pénicilline est un diagnostic d'allergie médicamenteuse courant chez les patients pédiatriques; cependant, après des tests d'allergie appropriés, bon nombre de ces patients ne présentent pas de véritable allergie. Pour ceux présentant une allergie signalée, des antibiotiques alternatifs sont prescrits, moins efficaces, plus toxiques ou plus coûteux. Peu de données permettent d'évaluer les allergies chez les enfants hospitalisés et de comparer les évaluations des allergies réalisées par les allergologues pédiatriques et les pharmaciens. Objectif: Estimer le pourcentage de patients pédiatriques admis avec une allergie à la pénicilline signalée, mais qui n'avaient pas de véritable allergie à la pénicilline. Méthodologie: Cette étude de cohorte prospective monocentrique comprenait des patients hospitalisés âgés de 6 mois à 17 ans, présentant une allergie documentée à la pénicilline, qui ont été admis dans les unités de pédiatrie générale et d'oncologie d'un hôpital pour enfants de soins tertiaires entre novembre 2019 et mars 2023. Les antécédents, l'évaluation et la catégorisation des risques de l'allergie ont été renseignés par les pharmaciens. L'anamnèse a été revue avec l'allergologue, et le patient a ensuite été référé, a subi un test cutané ou a reçu une provocation orale à l'amoxicilline avec surveillance pendant 1 heure. Résultats: Sur 30 patients inclus, 29 (97 %) ont vu un désétiquetage de leur allergie à la pénicilline. Quatre patients (13 %) ont bénéficié d'un désétiquetage sur la seule base de leurs antécédents, sans évaluation des risques. Vingt-cinq (83 %) patients ont été évalués comme présentant un faible risque; 24 d'entre eux ont bénéficié d'un désétiquetage à la suite d'une provocation orale, et 1 n'a pas terminé la provocation orale en raison d'un transfert vers un autre hôpital. Un patient (3 %) a été évalué comme présentant un risque modéré, avec un désétiquetage basé sur les résultats des tests cutanés et de la provocation orale. Les évaluations des risques par le pharmacien et l'allergologue concordaient dans 29 (97 %) des 30 cas. Conclusions: Les patients pédiatriques, y compris ceux atteints de cancers malins, sont souvent étiquetés à tort comme ayant une allergie à la pénicilline. Les pharmaciens sont en mesure de déterminer avec précision le risque réel d'allergie et de désétiqueter les allergies à la pénicilline chez les patients pédiatriques en milieu hospitalier.