Retrospective study of diffuse intrinsic pontine glioma in the Belgian population: a 25 year experience.

INTRODUCTION: Diffuse intrinsic pontine glioma is a rare disease with a high mortality. Our primary aim was to determine the incidence of this disease in Belgium. Secondly, we wanted to compare the treatment approach of Belgian pediatric oncology centres, to investigate possibilities for improvement. METHODS: We retrospectively collected and analysed data on DIPG-patients diagnosed between 1994 and 2018 and recorded in the Belgian Cancer Registry. We included patients ≤ 18 years who were followed in one of the eight Belgian pediatric oncology centres. RESULTS: We included 100 patients. Files were complete in 87 patients. We observed an increase in diagnoses with an incidence of 3.1 per 1,000,000 persons (aged 0-≤ 18) per year over the last 5 years compared to an overall incidence of 1.8. Biopsy was performed at diagnosis in 51.7% of patients. In one fifth this was study-related. Mutation analysis was known in eight patients, of which six showed the H3 K27M-mutation. 58.8% of patients received chemotherapy, without a significant survival benefit. 12.6% of patients were included in a clinical trial. Biopsy rate and the use of chemotherapy differed widely between centres. Mean OS and PFS were 10.49 and 4.87 months respectively. We observed an improved survival over time. CONCLUSIONS: Over the past 25 years, we observed an increase of new DIPG-diagnoses. Outcome in our cohort is comparable with literature findings. We demonstrate an important heterogeneity in treatment approach between different centres and limited inclusion in clinical trials. Therefore, collaboration between centres and inclusion of patients in clinical trials is much needed.

Anaphylaxis related to disinfection with chlorhexidine in a teenager treated for cancer.

INTRODUCTION: Literature shows upcoming allergy to chlorhexidine due to the widespread use of the disinfectant within and outside surgical settings. Only a few case reports have been published regarding the use of topical chlorhexidine disinfectant outside surgery and only a minority of these within the pediatric population. CASE REPORT: We present a case-report of a teenager, treated for acute lymphoblastic leukemia who developed an anaphylactic shock after repeated chlorhexidine use for skin disinfection at the insertion of a central venous catheter during his chemotherapy treatment. Preceding minor symptoms such as local swelling and pruritus were not recognized as possible allergy to chlorhexidine.Management and outcome: He was treated with two doses of intramuscular adrenaline and transferred to the pediatric intensive care unit where he fully recovered. Specific IgE testing was positive for chlorhexidine. A total avoidance of chlorhexidine was instructed. DISCUSSION: A similar case was published regarding an anaphylaxis after use of chlorhexidine disinfectant for a dialysis catheter. Almost all other case reports of anaphylactic shock were found within surgical settings or after insertion of an impregnated central venous catheter/urine catheter. We suggest that some of the disinfectant might have been flushed in the catheter and then caused an anaphylactic reaction. The link between symptoms and chlorhexidine was not made until an anaphylactic reaction occurred. Literature data show that chlorhexidine often causes mild preceding symptoms before an anaphylaxis occurs. So let awareness arise around this 'hidden allergen' of which warning reactions often are being missed.

Outcome of children relapsing after first allogeneic haematopoietic stem cell transplantation for acute myeloid leukaemia: a retrospective I-BFM analysis of 333 children.

Outcome of 333 children with acute myeloid leukaemia relapsing after a first allogeneic haematopoietic stem cell transplantation was analyzed. Four-year probability of overall survival (4y-pOS) was 14%. 4y-pOS for 122 children receiving a second haematopoietic stem cell transplantation was 31% and 3% for those that did not (P = <0·0001). Achievement of a subsequent remission impacted survival (P = <0·0001). For patients receiving a second transplant survival with or without achieving a subsequent remission was comparable. Graft source (bone marrow vs. peripheral blood stem cells, P = 0·046) and donor choice (matched family vs. matched unrelated donor, P = 0·029) positively impacted survival after relapse. Disease recurrence and non-relapse mortality at four years reached 45% and 22%.

Correction to: The pitfalls and promise of liquid biopsies for diagnosing and treating solid tumors in children: as review.

In the original version of this article, a reader pointed out that there was a mistake in the phrasing in a paragraph. This could potentially be harmful to children. The authors agree to change the wording. "vitreous fluid" will be changed to "aqueous humor".

The pitfalls and promise of liquid biopsies for diagnosing and treating solid tumors in children: a review.

Cell-free DNA profiling using patient blood is emerging as a non-invasive complementary technique for cancer genomic characterization. Since these liquid biopsies will soon be integrated into clinical trial protocols for pediatric cancer treatment, clinicians should be informed about potential applications and advantages but also weaknesses and potential pitfalls. Small retrospective studies comparing genetic alterations detected in liquid biopsies with tumor biopsies for pediatric solid tumor types are encouraging. Molecular detection of tumor markers in cell-free DNA could be used for earlier therapy response monitoring and residual disease detection as well as enabling detection of pathognomonic and therapeutically relevant genomic alterations.Conclusion: Existing analyses of liquid biopsies from children with solid tumors increasingly suggest a potential relevance for molecular diagnostics, prognostic assessment, and therapeutic decision-making. Gaps remain in the types of tumors studied and value of detection methods applied. Here we review the current stand of liquid biopsy studies for pediatric solid tumors with a dedicated focus on cell-free DNA analysis. There is legitimate hope that integrating fully validated liquid biopsy-based innovations into the standard of care will advance patient monitoring and personalized treatment of children battling solid cancers.What is Known:• Liquid biopsies are finding their way into routine oncological screening, diagnosis, and disease monitoring in adult cancer types fast.• The most widely adopted source for liquid biopsies is blood although other easily accessible body fluids, such as saliva, pleural effusions, urine, or cerebrospinal fluid (CSF) can also serve as sources for liquid biopsiesWhat is New:• Retrospective proof-of-concept studies in small cohorts illustrate that liquid biopsies in pediatric solid tumors yield tremendous potential to be used in diagnostics, for therapy response monitoring and in residual disease detection.• Liquid biopsy diagnostics could tackle some long-standing issues in the pediatric oncology field; they can enable accurate genetic diagnostics in previously unbiopsied tumor types like renal tumors or brain stem tumors leading to better treatment strategies.

Differentiation of Human Cardiac Atrial Appendage Stem Cells into Adult Cardiomyocytes: A Role for the Wnt Pathway?

Human cardiac stem cells isolated from atrial appendages based on aldehyde dehydrogenase activity (CASCs) can be expanded in vitro and differentiate into mature cardiomyocytes. In this study, we assess whether Wnt activation stimulates human CASC proliferation, whereas Wnt inhibition induces cardiac maturation. CASCs were cultured as described before. Conventional PCR confirmed the presence of the Frizzled receptors. Small-molecule inhibitors (IWP2, C59, XAV939, and IWR1-endo) and activator (CHIR99021) of the Wnt/ß -catenin signaling pathway were applied, and the effect on ß-catenin and target genes for proliferation and differentiation was assessed by Western blot and RT-qPCR. CASCs express multiple early cardiac differentiation markers and are committed toward myocardial differentiation. They express several Frizzled receptors, suggesting a role for Wnt signaling in clonogenicity, proliferation, and differentiation. Wnt activation increases total and active ß-catenin levels. However, this does not affect CASC proliferation or clonogenicity. Wnt inhibition upregulated early cardiac markers but could not induce mature myocardial differentiation. When CASCs are committed toward myocardial differentiation, the Wnt pathway is active and can be modulated. However, despite its role in cardiogenesis and myocardial differentiation of pluripotent stem-cell populations, our data indicate that Wnt signaling has limited effects on CASC clonogenicity, proliferation, and differentiation.

Cardiac atrial appendage stem cells promote angiogenesis in vitro and in vivo.

Cardiac atrial appendage stem cells (CASCs) show extraordinary myocardial differentiation properties, making them ideal candidates for myocardial regeneration. However, since the myocardium is a highly vascularized tissue, revascularization of the ischemic infarct area is essential for functional repair. Therefore, this study assessed if CASCs contribute to cardiac angiogenesis via paracrine mechanisms. First, it was demonstrated that CASCs produce and secrete high levels of numerous angiogenic growth factors, including vascular endothelial growth factor (VEGF), endothelin-1 (ET-1) and insulin-like growth factor binding protein 3 (IGFBP-3). Functional in vitro assays with a human microvascular endothelial cell line (HMEC-1) and CASC CM showed that CASCs promote endothelial cell proliferation, migration and tube formation, the most important steps of the angiogenesis process. Addition of inhibitory antibodies against identified growth factors could significantly reduce these effects, indicating their importance in CASC-induced neovascularization. The angiogenic potential of CASCs and CASC CM was also confirmed in a chorioallantoic membrane assay, demonstrating that CASCs promote blood vessel formation in vivo. In conclusion, this study shows that CASCs not only induce myocardial repair by cardiomyogenic differentiation, but also stimulate blood vessel formation by paracrine mechanisms. The angiogenic properties of CASCs further strengthen their therapeutic potential and make them an optimal stem cell source for the treatment of ischemic heart disease.

Mast cells protect from post-traumatic spinal cord damage in mice by degrading inflammation-associated cytokines via mouse mast cell protease 4.

Mast cells (MCs) are found abundantly in the central nervous system and play a complex role in neuroinflammatory diseases such as multiple sclerosis and stroke. In the present study, we show that MC-deficient Kit(W-sh/W-sh) mice display significantly increased astrogliosis and T cell infiltration as well as significantly reduced functional recovery after spinal cord injury compared to wildtype mice. In addition, MC-deficient mice show significantly increased levels of MCP-1, TNF-α, IL-10 and IL-13 protein levels in the spinal cord. Mice deficient in mouse mast cell protease 4 (mMCP4), an MC-specific chymase, also showed increased MCP-1, IL-6 and IL-13 protein levels in spinal cord samples and a decreased functional outcome after spinal cord injury. A degradation assay using supernatant from MCs derived from either mMCP4(-/-) mice or controls revealed that mMCP4 cleaves MCP-1, IL-6, and IL-13 suggesting a protective role for MC proteases in neuroinflammation. These data show for the first time that MCs may be protective after spinal cord injury and that they may reduce CNS damage by degrading inflammation-associated cytokines via the MC-specific chymase mMCP4.

The graft-versus-neuroblastoma effect of allogeneic hematopoietic stem cell transplantation, a review of clinical and experimental evidence and a perspective on mechanisms.

Despite aggressive treatment, patients with high-risk neuroblastoma face high relapse rates and bleak prognoses. Increasing evidence that neuroblastoma cells are or can become immunogenic has stimulated research into novel therapies based on triggering or enhancing tumor immunity. Here we review clinical and experimental studies on this subject, the underlying immune mechanisms and perspectives for clinical application. Allogeneic hematopoietic stem cell transplantation has proven to be of substantial benefit in the treatment of certain leukemias through the generation of a graft-versus-leukemia-effect and has become of interest as a possible treatment for patients with solid tumors, including neuroblastoma.

Diagnosis of pediatric central nervous system tumors using methylation profiling of cfDNA from cerebrospinal fluid.

Pediatric central nervous system tumors remain challenging to diagnose. Imaging approaches do not provide sufficient detail to discriminate between different tumor types, while the histopathological examination of tumor tissue shows high inter-observer variability. Recent studies have demonstrated the accurate classification of central nervous system tumors based on the DNA methylation profile of a tumor biopsy. However, a brain biopsy holds significant risk of bleeding and damaging the surrounding tissues. Liquid biopsy approaches analyzing circulating tumor DNA show high potential as an alternative and less invasive tool to study the DNA methylation pattern of tumors. Here, we explore the potential of classifying pediatric brain tumors based on methylation profiling of the circulating cell-free DNA (cfDNA) in cerebrospinal fluid (CSF). For this proof-of-concept study, we collected cerebrospinal fluid samples from 19 pediatric brain cancer patients via a ventricular drain placed for reasons of increased intracranial pressure. Analyses on the cfDNA showed high variability of cfDNA quantities across patients ranging from levels below the limit of quantification to 40 ng cfDNA per milliliter of CSF. Classification based on methylation profiling of cfDNA from CSF was correct for 7 out of 20 samples in our cohort. Accurate results were mostly observed in samples of high quality, more specifically those with limited high molecular weight DNA contamination. Interestingly, we show that centrifugation of the CSF prior to processing increases the fraction of fragmented cfDNA to high molecular weight DNA. In addition, classification was mostly correct for samples with high tumoral cfDNA fraction as estimated by computational deconvolution (> 40%). In summary, analysis of cfDNA in the CSF shows potential as a tool for diagnosing pediatric nervous system tumors especially in patients with high levels of tumoral cfDNA in the CSF. Further optimization of the collection procedure, experimental workflow and bioinformatic approach is required to also allow classification for patients with low tumoral fractions in the CSF.

METRO-PD1: Phase 1 study of nivolumab in combination with metronomic chemotherapy in children and adolescents with relapsing/refractory solid tumors.

BACKGROUND: This multicenter Phase I study (NCT03585465) evaluated nivolumab in combination with 3 metronomic chemotherapy (MC) regimens in children with refractory/relapsing solid tumors. OBJECTIVES: To evaluate the feasibility and safety of the three regimens METHODS: Patients aged < 18 years were enrolled. Nivolumab was combined with cyclophosphamide and vinblastine (arm A), capecitabine (arm B), or cyclophosphamide, vinblastine and capecitabine (arm C). Arm A and B were allocated sequentially. Arm C opened only if A and B were deemed safe. Dose-limiting toxicities (DLTs) were evaluated over the first two cycles. Patients were evaluable if they received > 2 cycles and > 70% of the planned dose. POPULATION: Sixteen patients were enrolled, 3 in arm A, 6 in arm B, and 7 in arm C. Median age was 11.5 years (range, 5-19). Patients previously received a median of 3.5 (range, 1-4) lines of systemic treatment, 14 patients had surgery and 11 had radiotherapy. RESULTS: Median number of cycles was 2 (1-24), median treatment duration was 56 days (18-714). In arm C, median number of cycles was 4 with median treatment duration of 95 days. No DLT was observed. Grade 3 adverse events (AE) and serious AE were observed in 8 patients (50%) and 1 patient (6%), respectively, over the first 2 cycles. No grade 4 AE occurred. The 6-month PFS and OS were 12% and 44%, respectively, in the whole population. Prolonged stable disease was observed in a high-grade glioma and an atypical teratoid rhabdoid tumor. CONCLUSION: Arm C appears safe. A randomized phase II trial evaluating the addition of nivolumab to the triple MC is ongoing.

Recipient leukocyte infusion enhances the local and systemic graft-versus-neuroblastoma effect of allogeneic bone marrow transplantation in mice.

Allogeneic hematopoietic stem cell transplantation and donor leukocyte infusion (DLI) may hold potential as a novel form of immunotherapy for high-risk neuroblastoma. DLI, however, carries the risk of graft-versus-host disease (GvHD). Recipient leukocyte infusion (RLI) induces graft-versus-leukemia responses without GvHD in mice and is currently being explored clinically. Here, we demonstrate that both DLI and RLI, when given to mixed C57BL/6→A/J radiation chimeras carrying subcutaneous Neuro2A neuroblastoma implants, can slow the local growth of such tumors. DLI provoked full donor chimerism and GvHD; RLI produced graft rejection but left mice healthy. Flow cytometric studies showed that the chimerism of intratumoral leukocytes paralleled the systemic chimerism. This was associated with increased CD8/CD4 ratios, CD8+ T-cell IFN-γ expression and NK-cell Granzyme B expression within the tumor, following both DLI and RLI. The clinically safe anti-tumor effect of RLI was further enhanced by adoptively transferred naïve recipient-type NK cells. In models of intravenous Neuro2A tumor challenge, allogeneic chimeras showed superior overall survival over syngeneic chimeras. Bioluminescence imaging in allogeneic chimeras challenged with luciferase-transduced Neuro2A cells showed both DLI and RLI to prolong metastasis-free survival. This is the first experimental evidence that RLI can safely produce a local and systemic anti-tumor effect against a solid tumor. Our data indicate that RLI may provide combined T-cell and NK-cell reactivity effectively targeting Neuro2A neuroblastoma.

IL-7 is required for the development of the intrinsic function of marginal zone B cells and the marginal zone microenvironment.

The characteristic microarchitecture of the marginal zone (MZ), formed by locally interacting MZ-specific B cells, macrophages, and endothelial cells, is critical for productive marginal zone B cell (MZB cell) Ab responses. Reportedly, IL-7-deficient mice, although severely lymphopenic, retain small numbers of CD21(high)CD23(low) B cells consistent with MZB cell phenotype, suggesting that IL-7 signaling is not exclusively required for MZB cell lymphopoiesis. In this study, we investigated the function of IL-7(-/-) MZB cells and the IL-7(-/-) microenvironment using a model of hamster heart xenograft rejection, which depends exclusively on MZB cell-mediated production of T cell-independent IgM xenoantibodies (IgMXAb). C57BL/6-IL-7(-/-) mice accepted xenografts indefinitely and failed to produce IgMXAb, even after transfer of additional IL-7(-/-) or wild-type C57BL/6 MZB cells. Transfer of wild-type but not IL-7(-/-) B cells enabled SCID mice to produce IgMXAb. When transferred to SCID mice, wild-type but not IL-7(-/-) B cells formed B cell follicles with clearly defined IgM(+), MOMA-1(+), and MAdCAM-1(+) MZ structures. Conversely, adoptively transferred GFP(+) C57BL/6 B cells homed to the MZ area in a SCID but not an IL-7(-/-) environment. Naive IL-7(-/-) mice showed absent or aberrant splenic B cell structures. We provide evidence that IL-7 is critical for the development of the intrinsic function of MZB cells in producing rapidly induced IgM against T cell-independent type II Ags, for their homing potential, and for the development of a functional MZ microanatomy capable of attracting and lodging MZB cells.

Correction: van de Velde et al. Vincristine-Induced Peripheral Neuropathy in Pediatric Oncology: A Randomized Controlled Trial Comparing Push Injections with One-Hour Infusions (The VINCA Trial). Cancers 2020, 12, 3745.

In the original publication, there was a mistake in Table 1 as published [...].

Randomized controlled trial on the effect of 1-hour infusion of vincristine versus push injection on neuropathy in children with cancer (final analysis).

INTRODUCTION: Vincristine is an integral component of treatment for children with cancer. Its main dose-limiting side effect is vincristine-induced peripheral neuropathy (VIPN). The VINCA trial was a randomized controlled trial that explored the effect of 1-hour infusion compared with push injection of vincristine on the development of VIPN in children with cancer. The short-term outcomes (median follow-up 9 months) showed that there was no difference in VIPN between the randomization groups. However, 1-hour infusion was less toxic in children who also received azoles. We now report the results of the final analyses (median follow-up 20 months), which includes treatment outcome as a secondary objective (follow-up 3 years). METHODS: VIPN was measured 1-7 times per participant using the Common Terminology Criteria for Adverse Events (CTCAE) and the pediatric-modified total neuropathy score. Poisson mixed model and logistic generalized estimating equation analysis for repeated measures were performed. RESULTS: Forty-five participants per randomization group were included. There was no significant effect of 1-hour infusion compared with push injection on VIPN. In participants receiving concurrent azoles, the total CTCAE score was significantly lower in the one-hour group (rate ratio 0.52, 95% confidence interval 0.33-0.80, p = 0.003). Four patients in the one-hour group and one patient in the push group relapsed. Two patients in the one-hour group died. CONCLUSION: 1-hour infusion of vincristine is not protective against VIPN. However, in patients receiving concurrent azoles, 1-hour infusion may be less toxic. The difference in treatment outcome is most likely the result of differences in risk profile.

Genetic Polymorphisms Associated with Vincristine Pharmacokinetics and Vincristine-Induced Peripheral Neuropathy in Pediatric Oncology Patients.

Vincristine (VCR) is an important component of curative chemotherapy for many childhood cancers. Its main side effect is VCR-induced peripheral neuropathy (VIPN), a dose limiting toxicity. Some children are more susceptible to VIPN, which is at least partially dependent on genetic factors and pharmacokinetics (PK). In this study, we identify and replicate genetic variants associated with VCR PK and VIPN. Patient samples from a randomized clinical trial studying the effect of administration duration of VCR on VIPN in 90 patients were used. PK sampling was conducted on between one and five occasions at multiple time points. A linear two-compartment model with first-order elimination was used, and targeted next-generation DNA sequencing was performed. Genotype-trait associations were analyzed using mixed-effect models or logistic regression analysis for repeated measures, or Poisson regression analysis in which the highest VIPN score per patient was included. Nine single-nucleotide polymorphisms (SNPs) in seven genes (NDRG1, GARS, FIG4, FGD4, SEPTIN9, CEP72, and ETAA1) were associated with VIPN. Furthermore, three SNPs in three genes (MTNR1B, RAB7A and SNU13) were associated with PK of VCR. In conclusion, PK of VCR and VIPN are influenced by SNPs; upfront identification of those that lead to an altered susceptibility to VIPN or VCR exposure could help individualize VCR treatment.

The feasibility of using liquid biopsies as a complementary assay for copy number aberration profiling in routinely collected paediatric cancer patient samples.

BACKGROUND: Paediatric tumours are often characterised by the presence of recurrent DNA copy number alterations (CNAs). These DNA copy number profiles, obtained from a tissue biopsy, can aid in the correct prognostic classification and therapeutic stratification of several paediatric cancer entities (e.g. MYCN amplification in neuroblastoma) and are part of the routine diagnostic practice. Liquid biopsies (LQBs) offer a potentially safer alternative for such invasive tumour tissue biopsies and can provide deeper insight into tumour heterogeneity. PROCEDURE: The robustness and reliability of LQB CNA analyses was evaluated. We performed retrospective CNA profiling using shallow whole-genome sequencing (sWGS) on paired plasma circulating cell-free DNA (cfDNA) and tissue DNA samples from routinely collected samples from paediatric patients (n = 128) representing different tumour entities, including osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, Wilms tumour, brain tumours and neuroblastoma. RESULTS: Overall, we observed a good concordance between CNAs in tissue DNA and cfDNA. The main cause of CNA discordance was found to be low cfDNA sample quality (i.e. the ratio of cfDNA (<700 bp) and high molecular weight DNA (>700 bp)). Furthermore, CNAs were observed that were present in cfDNA and not in tissue DNA, or vice-versa. In neuroblastoma samples, no false-positives or false-negatives were identified for the detection of the prognostic marker MYCN amplification. CONCLUSION: In future prospective studies, CNA analysis on LQBs that are of sufficient quality can serve as a complementary assay for CNA analysis on tissue biopsies, as either cfDNA or tissue DNA can contain CNAs that cannot be identified in the other biomaterial.

Hearing Loss in Malignant Infantile Osteopetrosis: A Case-Based Review.

Osteopetrosis, or marble bone disease, is a rare genetic disease of bone resorption. It includes a clinically heterogeneous group of conditions that are characterized by increased bone density on radiographs due to a defect in osteoclasts. A most common feature of osteopetrosis of the temporal bone is hearing impairment. This case-based review describes the potential otologic and hearing manifestations of malignant infantile osteopetrosis. The hearing loss can be conductive, sensorineural, late-onset or relapsing. Once the diagnosis is made, referral to an ENT physician for hearing evaluation is indicated. Although otitis media with effusion is the most frequent cause of conductive hearing loss with autosomal recessive osteopetrotic patients, audiometry after tympanostomy tube placement to check for additional causes of hearing loss is highly recommended. As otological manifestations may worsen over time, accurate and regular follow-up by audiometry is necessary. According to our knowledge, this is the first case report in the literature of dehiscent jugular bulb in a patient with osteopetrosis.

The association between vincristine-induced peripheral neuropathy and health-related quality of life in children with cancer.

PURPOSE: Vincristine (VCR) is a chemotherapeutic agent used in the treatment of pediatric oncology patients, but its main toxicity is VCR-induced peripheral neuropathy (VIPN). However, whether VIPN has an effect on health-related quality of life (HR-QoL) in children during treatment is unknown. Therefore, the aim of our study was to investigate the association between VIPN and HR-QoL in children starting treatment for cancer. METHODS: Measurements of VIPN were performed using two tools: Common Terminology Criteria for Adverse Events (CTCAE) and pediatric-modified Total Neuropathy Score (ped-mTNS). Assessment of HR-QoL was done with self- and proxy assessment of the Cancer and Generic module of the Pediatric Cancer Quality of Life Inventory™ (PedsQL). RESULTS: In total, N = 86 children were included. HR-QoL of children with VIPN (n = 67%, 76%) was significantly lower in comparison with children without VIPN: estimated Total score of PedsQL Generic (proxy) 84.57; ß = -8.96 and 95% confidence interval (CI) -14.48 to -3.43; p = 0.002, estimated PedsQL Generic Total score (self-reported): 85.16, ß = -8.38 (95% CI: -13.76 to -3.00); p = 0.003. Similar results were found in the Pain and Hurt domain of the PedsQL Cancer (pain: estimated score [proxy]: 85.28, ß = -9.94 [95%CI: -16.44 to -3.45], p = 0.003; hurt: estimated score [self-report] 97.57, ß = -19.15 [95%CI: -26.82 to -11.48], p < 0.001). CONCLUSION: VIPN results in a significant reduction of HR-QoL in children under treatment for a malignancy, which means that VIPN is important for the well-being of pediatric oncology patients. Therefore, this study underlines the importance of optimizing treatment with VCR, thereby aiming to reduce VIPN while maintaining efficacy.

Population Pharmacokinetics of Vincristine Related to Infusion Duration and Peripheral Neuropathy in Pediatric Oncology Patients.

Vincristine (VCR) is frequently used in pediatric oncology and can be administered intravenously through push injections or 1 h infusions. The effects of administration duration on population pharmacokinetics (PK) are unknown. We described PK differences related to administration duration and the relation between PK and VCR-induced peripheral neuropathy (VIPN). PK was assessed in 1-5 occasions (1-8 samples in 24 h per occasion). Samples were analyzed using high-performance liquid chromatography/tandem mass spectrometry. Population PK of VCR and its relationship with administration duration was determined using a non-linear mixed effect. We estimated individual post-hoc parameters: area under the concentration time curve (AUC) and maximum concentration (Cmax) in the plasma and peripheral compartment. VIPN was assessed using Common Terminology Criteria for Adverse Events (CTCAE) and the pediatric-modified total neuropathy score (ped-mTNS). Overall, 70 PK assessments in 35 children were evaluated. The population estimated that the intercompartmental clearance (IC-Cl), volume of the peripheral compartment (V2), and Cmax were significantly higher in the push group. Furthermore, higher IC-Cl was significantly correlated with VIPN development. Administration of VCR by push led to increased IC-Cl, V2, and Cmax, but were similar to AUC, compared to 1 h infusions. Administration of VCR by 1 h infusions led to similar or higher exposure of VCR without increasing VIPN.