Pediatric pulmonary thromboembolism: a 3-year Canadian Pediatric Surveillance Program study

BACKGROUND

Pediatric pulmonary embolism (PE) is a rare event associated with significant morbidity and mortality. Awareness of clinical presentation and practices unique to children may aid clinicians in prompt identification and treatment.

OBJECTIVES

To describe the incidence, risk factors, clinical presentation, diagnostic and therapeutic practices, and short-term outcomes of pediatric PE.

METHODS

We conducted a 3-year national surveillance study through the Canadian Pediatric Surveillance Program. Over 2800 pediatric specialists and subspecialists were contacted monthly from 2020 to 2022 and requested to report all new cases of PE in patients up to 18 years of age. Case-specific data were obtained through voluntary completion of a detailed questionnaire.

RESULTS

Fifty-eight cases (78% female, n = 45) were reported (2.4 cases per million children), with rates highest in adolescents 15 to 18 years (6.6 cases per million). Detailed information, available for 31 (53%) cases, documented at least 1 risk factor in 28 (90%) cases; 24 (77%) patients presented with 2 or more symptoms. Computed tomography pulmonary angiography was used for diagnostic confirmation in 25 (81%) cases. Anticoagulation was initiated in 24 (77%) of 31 cases; fewer than 5 patients underwent thrombolysis or surgical interventions. Of 28 patients who received therapeutic interventions, 8 (29%) experienced treatment-related complications. Fewer than 5 mortalities were reported.

CONCLUSION

Pediatric PE is a rare event, with female adolescents at the highest risk. Although the presentation is often nonspecific, clinicians should maintain a high index of suspicion, particularly in patients with risk factors and when other diagnoses that may explain symptoms have been excluded.

Access to innovative therapies in pediatric oncology: Report of the nationwide experience in Canada

BACKGROUND

The need for new therapies to improve survival and outcomes in pediatric oncology along with the lack of approval and accessible clinical trials has led to "out-of-trial" use of innovative therapies. We conducted a retrospective analysis of requests for innovative anticancer therapy in Canadian pediatric oncology tertiary centers for patients less than 30 years old between 2013 and 2020.

METHODS

Innovative therapies were defined as cancer-directed drugs used (a) off-label, (b) unlicensed drugs being used outside the context of a clinical trial, or (c) approved drugs with limited evidence in pediatrics. We excluded cytotoxic chemotherapy, cellular products, and cytokines.

RESULTS

We retrieved data on 352 innovative therapy drug requests. Underlying diagnosis was primary CNS tumor 31%; extracranial solid tumor 37%, leukemia/lymphoma 22%, LCH 2%, and plexiform neurofibroma 6%. RAS/MAP kinase pathway inhibitors were the most frequently requested innovative therapies in 28% of all requests followed by multi-targeted tyrosine kinase inhibitors (17%), inhibitors of the PIK3CA-mTOR-AKT pathway (8%), immune checkpoints inhibitors (8%), and antibody drug conjugates (8%). In 112 out of 352 requests, innovative therapies were used in combination with another anticancer agent. 48% of requests were motivated by the presence of an actionable molecular target. Compassionate access accounted for 52% of all requests while public insurance was used in 27%. Mechanisms of funding varied between provinces.

CONCLUSION

This real-world data collection illustrates an increasing use of "out-of-trial" innovative therapies in pediatric oncology. This new field of practice warrants further studies to understand the impact on patient trajectory and equity in access to innovative therapies.

Abstract 4509: A pan-Canadian precision oncology program for children, adolescents and young adults with hard-to-cure cancer: The PRecision Oncology For Young peopLE (PROFYLE) Program

Background: Over 4,300 children, adolescents, and young adults (CAYA) are diagnosed with cancer each year in Canada, 1/3 of whom have refractory/metastatic disease or will relapse. The PRecision Oncology For Young peopLE (PROFYLE) national, collaborative program, was created to provide equitable access to molecular profiling to identify novel targeted treatment options in a clinically relevant timeframe for all CAYA with hard-to-cure cancers in Canada.

Design: Building upon 3 pre-existing regional precision oncology programs, PROFYLE now includes >20 institutions and has united an interdisciplinary team of experts, leaders, research teams, end-users and advocates from across Canada. The program has 14 domain specific nodes that are unified by a shared governance structure, and has harmonized biobanking, genomics, bioinformatics and reporting procedures. PROFYLE includes genomic and transcriptomic sequencing of paired germline and cancer fresh/frozen samples, proteomic analysis, and cancer modelling. Inclusion criteria: ≤29y; treatment at a Canadian center; diagnosis of a hard-to-cure cancer. Profiling results are reviewed by multidisciplinary Molecular Tumor Boards. A report including a results/recommendations summary of actionable findings (therapeutic, diagnostic, prognostic, cancer predisposition), potential targeted therapy options including available clinical trials, clarification of diagnosis, and genetic counseling recommendations is provided to the treating oncologist.

Results: >1,000 CAYA are included from all of the provinces. Cancer diagnoses: 34% sarcoma, 16% leukemia/lymphoma, 16% CNS tumor, 11% neuroblastoma, 23% other. 17% of participants had a cancer-predisposing pathogenic/likely pathogenic germline variant, 45% had ≥1 potentially actionable somatic alteration, 22.6% had a therapeutically targetable somatic alteration. The most frequent classes of therapeutic alterations were RAS/MAPK (15%), cell cycle (14%), epigenetic (13%), RTK (12%), PI3K/AKT/mTOR (11%), DNA repair (9%), immune checkpoint (8%). Of clinicians who reported the utility of results, 55% indicated the findings were useful for clinical management.

Future Directions: Collaborations with other national and international initiatives and data from this interdisciplinary, multi-institutional research program will inform the development of a framework to innovatively link research, clinical and system considerations with Canadian values relevant to multi-omic profiling and drug access for CAYA. In addition, we believe that with a comprehensive molecular view of cancer, PROFYLE will transform our understanding of underlying disease mechanisms, facilitate and improve diagnostic and prognostic indicators, and identify new therapeutic strategies and targets for CAYA patients with cancer.

Citation Format: Stephanie A. Grover, Lesleigh Abbott, Jason N. Berman, Guillaume Bourque, Jennifer A. Chan, Avram E. Denburg, Rebecca J. Deyell, Conrad V. Fernandez, Cynthia Hawkins, Jan-Willem Henning, Meredith S. Irwin, Nada Jabado, Steven J. Jones, Philipp F. Lange, Paul Moorehead, Michael F. Moran, Daniel A. Morgenstern, Sapna Oberoi, Antonia Palmer, Shahrad R. Rassekh, Donna L. Senger, Adam Shlien, Daniel Sinnett, Caron Strahlendorf, Patrick J. Sullivan, Michael D. Taylor, Suzanne Vercauteren, Anita Villani, Stephanie Villeneuve, James A. Whitlock, David Malkin, on behalf of the PROFYLE Consortium. A pan-Canadian precision oncology program for children, adolescents and young adults with hard-to-cure cancer: The PRecision Oncology For Young peopLE (PROFYLE) Program. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4509.

Emicizumab in people with moderate or mild haemophilia A (HAVEN 6): a multicentre, open-label, single-arm, phase 3 study

BACKGROUND

Clinical trial data are scarce for the use of prophylaxis in people with non-severe haemophilia A. The HAVEN 6 study aims to assess safety and efficacy of emicizumab prophylaxis in people with non-severe haemophilia A without factor VIII (FVIII) inhibitors.

METHODS

HAVEN 6 is a multicentre, open-label, single-arm, phase 3 study taking place in 22 specialty clinics and hospitals in Europe, North America, and South Africa. Eligible participants were people of all ages weighing at least 3 kg with a diagnosis of moderate (FVIII activity ≥1%-≤5%) or mild (FVIII >5%-<40%) haemophilia A without FVIII inhibitors requiring prophylaxis as assessed by the treating physician. Participants received subcutaneous emicizumab 3 mg/kg of bodyweight once weekly for 4 weeks, followed by the participant's choice of maintenance dose: 1·5 mg/kg once weekly, 3 mg/kg every 2 weeks, or 6 mg/kg every 4 weeks. Safety was the primary objective of the study. Safety endpoints included adverse events, serious adverse events, and adverse events of special interest including thromboembolic events and thrombotic microangiopathies. The primary efficacy endpoint was the annualised bleed rate for treated bleeds. Analyses were done for participants who received at least one dose of emicizumab. This study is registered with ClinicalTrials.gov, number NCT04158648, and is active but not recruiting.

FINDINGS

Between Feb 10, 2020, and Aug 31, 2021, we assigned 73 people to treatment. 72 participants received at least one dose of emicizumab (51 moderate [71%]; 21 mild [29%]; 69 male [96%]; three female [4%]; and 61 White [85%]). Median age was 23·5 years (IQR 12·0-36·0); median follow-up was 55·6 weeks (IQR 52·3-61·6) weeks. At baseline, 24 participants (33%) had target joints and 37 (51%) were receiving FVIII prophylaxis. 60 participants (83%) had at least one adverse event; the most common adverse events were headache (in 12 participants [17%]), injection-site reaction (12 [17%]), and arthralgia (11 [15%]). 15 (21%) had at least one emicizumab-related adverse event; no adverse events led to treatment withdrawal, modification, or interruption. Eight participants (11%) reported ten serious adverse events in total, none emicizumab-related. There were no deaths or thrombotic microangiopathies. One participant had grade 1 thrombosed haemorrhoids (classified as a thromboembolic event), unrelated to emicizumab. The annualised bleed rate was 0·9 (95% CI 0·55-1·52) for treated bleeds. 48 participants (67%) had no treated bleeds. All-bleed annualised bleed rates were 10·1 (95% CI 6·93-14·76) from 24 weeks pre-study and 2·3 (1·67-3·12) on-study after a median follow-up of 55·6 weeks.

INTERPRETATION

These data show efficacy and a favourable safety profile of emicizumab in people with non-severe haemophilia A without FVIII inhibitors who warrant prophylaxis, confirming emicizumab as a valuable treatment option in this population.

FUNDING

F Hoffmann-La Roche.

Evaluating a Transition Workbook for Childhood Cancer Survivors: a Pilot Study

Many childhood cancer survivors (CCS) could benefit from improved knowledge about their cancer diagnosis, the treatments received, and associated risks during the period when they transition into adult aftercare. Interventions that support the transition from pediatric to adult care have showed high patient satisfaction. We developed an educational workbook, "Life After the Janeway," to support CCS transition into adult care. We evaluated its understandability, actionability, and overall acceptability, using an online survey based on the Agency for Healthcare Research and Quality's Patient Education Materials Assessment Tool for Printable Material (PEMAT-P). Ten participants completed the survey. The overall PEMAT-P score was 94.06 (SD ± 7.40). Mean scores for understandability and actionability were 92.83 (SD ± 8.79) and 98.15 (SD ± 5.24) respectively. Interrater reliability found strong agreement across survey items. Participants support efforts to improve transition and felt positive about the intervention. The workbook was shown to be understandable and actionable to likely users. The next steps will focus on delivering the workbook to CCS going through their transition of care and exploring developing the workbook in an electronic format.

Transition from pediatric to adult aftercare for survivors of pediatric cancer in Newfoundland and Labrador: a qualitative study

BACKGROUND

Childhood cancer survivors (CCSs) face increased risks during the period when they leave pediatric care and transition into adult-focused aftercare. We examined the experiences of CCSs entering adult-focused aftercare to gain a better understanding of current transition practices and barriers to transition, and to identify opportunities for improving care.

METHODS

We conducted a qualitative study using in-person and telephone semi-structured interviews. Childhood cancer survivors who recently transitioned out of pediatric care and health care providers (HCPs) who provide care for CCSs in Newfoundland and Labrador were identified using purposive sampling. Participants were interviewed between July 2017 and March 2019. Data were analyzed using both qualitative descriptive and thematic analysis.

RESULTS

We conducted interviews with 5 CCSs and 9 HCPs. All CCSs interviewed reported receiving aftercare through their pediatric oncology program; only 2 reported receiving any form of aftercare in the adult setting. The lack of a structured transition process for CCSs in the province emerged as a theme in this study. Interview participants identified several barriers to transition: the added challenges for survivors in rural areas, changes in the availability of services after the transition to adult-focused aftercare, challenges associated with navigating the adult system, and a lack of education on transitioning into adult aftercare.

INTERPRETATION

We found that there was little preparation for the transition of CCSs into adult care, and their aftercare was disrupted. Programs serving CCSs have opportunities to improve care by standardizing and better supporting these transitions, for example through the development of context-appropriate educational resources.

Incidence and risk factors of venous thrombotic events in pediatric patients with CNS tumors compared with non-CNS cancer: A population-based cohort study

BACKGROUND

Venous thromboembolism (VTE) is a well-recognized complication in pediatric cancer patients. It has been demonstrated that the incidence of VTE in pediatric patients with central nervous system (CNS) tumors is lower than that of patients with other cancers. Risk factors for developing cancer-related thrombosis are numerous and can include patient, disease, or treatment-related influences. The present study was designed to assess the VTE incidence in a pediatric oncology population, and to investigate whether intensity of treatment has similar associated with risk of VTE development in patients with and without CNS tumors.

METHODS

A retrospective population-based cohort study of pediatric oncology patients in Atlantic Canada was conducted. Data collected from medical records included demographics, cancer type, treatment, presence of central venous catheters (CVC), and presence of thrombosis. Treatment intensity was assessed using the intensity of treatment rating scale (ITR-3). Study period was from January 2000 to December 2017. SPSS version 24 was used for statistical analysis.

RESULTS

Of 1262 patients with pediatric cancer, 247 (19.6%) had CNS tumors. VTE occurred in significantly fewer (n = 5, 2%) patients with CNS tumors compared with patients with non-CNS cancers (n = 79, 7.8%) (p = 0.001). The ITR-3 scores did not differ significantly between the CNS and non-CNS groups (p = 0.638). In a multivariate logistic regression analysis, ITR-3 score was associated with VTE (odds ratio [OR]: 1.48, 95% CI: 1.2-1.9), while presence of CNS tumor was protective (OR: 0.26, 95% CI: 0.1-0.6).

CONCLUSIONS

We demonstrate that pediatric patients with CNS tumors experience a significantly lower incidence of VTE compared with patients with non-CNS cancer. An increase in the ITR-3 rating significantly increased the odds of developing VTE.

Identification of Novel Adenosine Deaminase 2 Gene Variants and Varied Clinical Phenotype in Pediatric Vasculitis

OBJECTIVE

Individuals with deficiency of adenosine deaminase 2 (DADA2), a recently recognized autosomal recessive disease, present with various systemic vascular and inflammatory manifestations, often with young age at disease onset or with early onset of recurrent strokes. Their clinical features and histologic findings overlap with those of childhood-onset polyarteritis nodosa (PAN), a primary "idiopathic" systemic vasculitis. Despite similar clinical presentation, individuals with DADA2 may respond better to biologic therapy than to traditional immunosuppression. The aim of this study was to screen an international registry of children with systemic primary vasculitis for variants in ADA2.

METHODS

The coding exons of ADA2 were sequenced in 60 children and adolescents with a diagnosis of PAN, cutaneous PAN, or unclassifiable vasculitis (UCV), any chronic vasculitis with onset at age 5 years or younger, or history of stroke. The functional consequences of the identified variants were assessed by ADA2 enzyme assay and immunoblotting.

RESULTS

Nine children with DADA2 (5 with PAN, 3 with UCV, and 1 with antineutrophil cytoplasmic antibody-associated vasculitis) were identified. Among them, 1 patient had no rare variants in the coding region of ADA2 and 8 had biallelic, rare variants (minor allele frequency <0.01) with a known association with DADA2 (p.Gly47Arg and p.Gly47Ala) or a novel association (p.Arg9Trp, p.Leu351Gln, and p.Ala357Thr). The clinical phenotype varied widely.

CONCLUSION

These findings support previous observations indicating that DADA2 has extensive genotypic and phenotypic variability. Thus, screening ADA2 among children with vasculitic rash, UCV, PAN, or unexplained, early-onset central nervous system disease with systemic inflammation may enable an earlier diagnosis of DADA2.