Kuhn, Alexis

ABSTRACT As interest in the use of cannabinoids for supportive care in pediatric cancers grows, there are emerging concerns about potential interactions with antineoplastic agents. This review provides an overview of potential drug–drug interactions between cannabinoids and 25 antineoplastic agents commonly used in pediatric hematology/oncology. Antineoplastic agents were stratified into low, medium, or high interaction risk based on the potential impact of cannabinoids on metabolic and/or pharmacodynamic pathways. The antineoplastic agents identified as high risk for interactions with cannabinoids included cyclophosphamide, doxorubicin, etoposide, ifosfamide, irinotecan, vinblastine, and vincristine. Key mechanisms of interaction include inhibition of cytochrome P450 enzymes and UDP‐glucuronosyltransferases and modulation of drug transporters such as P‐glycoprotein and breast cancer resistance protein. There is emerging evidence of a synergistic effect between cannabinoids and antineoplastic agents such as temozolomide, vinblastine, vinorelbine, and irinotecan. Pediatric patients exhibit developmental differences in drug metabolism and transporter expression, yet most pharmacokinetic data on cannabinoids are extrapolated from adult studies. There is a lack of pediatric‐specific safety, efficacy, and dosing data that underscores the need for age‐appropriate studies to ensure safe and effective integration of cannabinoids in pediatric cancer care.

There have been no large comparisons of the clinical and laboratory features of familial neonatal hemophagocytosis (f-nHLH) and infectious neonatal hemophagocytosis (i-nHLH). The objectives of this study were the following: (1) Describe the demographic, diagnostic, and clinical features of patients with familial nHLH (F-nHLH) and infectious HLH (i-nHLH). (2) Compare key variables between f-nHLH and i-nHLH. (3) Compare the clinical outcomes of f-nHLH and i-nHLH. (4) Summarize literature on cytokine levels in patients with nHLH. Data from a previously published nHLH meta-analysis report were used to describe and compare features of infants with f-nHLH versus i-nHLH. Variables were tested with the χ 2 test or Fisher exact test, Cochran-Armitage test, independent 2-sample t test, or Wilcoxon rank-sum test as appropriate. Odds ratios were calculated for any comparison with a P -value of <0.05. Data extracted from 99 cases of f-nHLH and 54 cases of i-nHLH were included in this analysis. Infants with f-HLH met HLH criteria at the following rates: fever (84%); organomegaly (100%); pancytopenia (75%); hypofibrinogenemia (84%); hypertriglyceridemia (48%); hypofibrinogenemia or hypertriglyceridemia (82%); hemophagocytosis (81%); hyperferritinemia (99%); low or absent NK cell activity (91%); and elevated soluble CCD25 (91%). Infants with i-nHLH had higher median ferritin levels (22,537 ng/mL) than infants with f-nHLH (7587 ng/mL) ( P =0.072). Infants with f-nHLH had higher rates of symptoms in utero, preterm birth, family history of HLH, and family history of infant death. The overall survival among infants with familial nHLH was lower than infectious nHLH ( P =0.037). Management of nHLH requires rapid diagnosis and prompt treatment, as current literature suggests nHLH has high mortality rates. Distinguishing between familial and infectious causes of nHLH can aid in determining the correct treatment of choice.

Abstract Background Revaccination is required for patients who receive a hematopoietic cell transplant (HCT) to reduce vaccine preventable illness. Revaccination requires an individualized plan due to differences in immunosuppressive therapy, immune reconstitution, age, and other challenges such as graft versus host disease. A structured approach is required to ensure prompt initiation of re-vaccinations and completion of the re-vaccination schedule. This study sought to evaluate the re-vaccination process at our center as a baseline for quality improvement. Methods We conducted a retrospective chart review of pediatric patients who received an autologous or allogeneic HCT between January 2019 and March 2024 to assess time to starting re-vaccination after post-HCT medical clearance and percentage of patients up to date within each series of vaccinations per internal protocol. Results A total of 64 patients were evaluated, of whom 23 were female and 35 underwent allogeneic stem cell transplant. For analysis, 13 were excluded due to death prior to clearance for vaccination. Among those included, 42 patients were cleared for restarting vaccines, and 37 (88%) of those have received at least one vaccine, while only 25 (59%) have completed the first series of recommended vaccines. The average time from transplant to administration of the first vaccine was 431 days for autologous HCT and 459 days for allogeneic HCT. The average time from medical clearance to the first vaccine was 66 days. The mean interval between the first and second vaccine doses was 97 days. Conclusion The majority of eligible patients initiated re-vaccination after transplant, but rates for the receipt of full recommended initial series remained suboptimal, with notable delays with notable delays between transplant and the day of clearance as well as clearance and the first vaccine administered. These findings highlight significant gaps in post-transplant immunization practices and underscore the need for targeted interventions to optimize protection for this vulnerable population. Disclosures All Authors: No reported disclosures

Summary Recipients of haploidentical and unrelated haematopoietic cell transplants (HCTs) historically had a higher risk for graft‐versus‐host disease (GvHD). However, with improved GvHD prophylaxis, recent data suggest adult patients undergoing transplantation from unrelated or mismatched donors now experience the rates of GvHD similar to those receiving matched related donor grafts. This finding is not yet explored in paediatric patients. The objectives of this study were to: (1) compare acute and chronic GvHD incidence, mortality and GvHD‐free relapse‐free survival (GRFS) among matched related donor (MRD), matched unrelated donor (MUD) and haploidentical paediatric HCT recipients in the era of enhanced GvHD prophylaxis for high‐risk patients, (2) identify independent risk factors for GvHD and (3) evaluate the efficacy of various GvHD prophylactic regimens in our cohort. We conducted a retrospective, single‐centre medical record abstraction among patients aged 0–25 years who underwent allogeneic HCT for any indication. The results demonstrated that 5‐year cumulative incidence rates of any GvHD, all‐cause mortality and GRFS are similar across the haploidentical, MRD and MUD groups. Tacrolimus‐containing doublet/triplet regimens were associated with decreased GvHD, as compared to ciclosporin. Adding alemtuzumab also decreased risk for GvHD, without increasing relapse rates. Prospective studies with larger cohorts are warranted to further optimize outcomes for paediatric allogeneic HCT patients.

ABSTRACT Background Patients at high risk for cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplant (HCT) should receive CMV prophylaxis. Historically, ganciclovir has been the preferred agent. However, its side effect profile, particularly myelosuppression, is undesirable. Letermovir is a newer agent that is not myelosuppressive and has replaced ganciclovir as the preferred agent for CMV prophylaxis in high‐risk adult patients. Methods The primary objective was to compare the incidence of dose modifications or discontinuation of CMV prophylaxis between pediatric patients who received ganciclovir versus letermovir. Secondary objectives included comparing the use of granulocyte colony‐stimulating factor (G‐CSF) support and the incidence of CMV DNAemia. We reviewed records of all pediatric patients who received an HCT at our institution between 2000 and 2024 and received either ganciclovir/valganciclovir or letermovir for CMV prophylaxis. Results Between 2000 and 2024, 65 pediatric patients receiving prophylactic ganciclovir, valganciclovir, or letermovir were evaluated. The median age at transplant was 12.2 years. No patients receiving letermovir required dose modification or discontinuation as opposed to 14 (29.2%) patients receiving ganciclovir ( p = 0.014). After engraftment, 12 (25%) patients receiving ganciclovir required G‐CSF support compared to seven (41.2%) patients receiving letermovir ( p = 0.23). In the ganciclovir group, 10 (20.8%) patients experienced CMV infection versus one (5.9%) patient receiving letermovir ( p = 0.26). Conclusion Compared with those receiving letermovir, a significantly higher proportion of patients in the ganciclovir/valganciclovir group experienced dose modifications or discontinuation of CMV prophylaxis due to adverse effects. Letermovir shows great promise as a CMV prophylactic agent in pediatric HCT patients due to its favorable side effect profile.

AbstractBackgroundΕ‐Aminocaproic acid oral solution (EACA OS) is the only commercially available antifibrinolytic for patients who cannot swallow tablets. Insurance denials and high costs remain barriers to its use.ObjectivesTo determine the safety and efficacy of crushed tranexamic acid tablets in water (cTXAw) for children with bleeding disorders.MethodsWe retrospectively reviewed records of children (<10 years) with bleeding disorders who received cTXAw or EACA OS from 1 December 2018, through 31 July 2022, at Mayo Clinic (Rochester, Minnesota). Bleeding outcomes were defined according to ISTH criteria.ResultsThirty‐two patients were included (median age, 3 years; male, n = 23). Diagnoses were VWD (n = 17), haemophilia (n = 5), FVII deficiency (n = 3), inherited platelet disorder (n = 4), ITP (n = 2), and combined FV and FVII deficiencies (n = 1). Thirty‐two courses of cTXAw (monotherapy 24/32; mean duration 6 days) and fifteen courses of EACA (monotherapy 12/15; mean duration 5 days) were administered. No surgical procedures (n = 28) were complicated by bleeding. Of the 19 bleeding events, 16 had effective haemostasis, two had no reported outcome, and one had no response. cTXAw and EACA were equally effective in preventing and treating bleeding (p value > .1). No patients had adverse effects. Eight of 19 patients (42%) who were initially prescribed EACA OS did not receive it because of cost or insurance denial.The estimated average wholesale price of one treatment was $94 for cTXAw and $905 for EACA OS.ConclusionsCTXAw appears to be an effective, safe, and low‐cost alternative option to EACA OS for young children with bleeding disorders.

A 13-year-old male undergoing maintenance chemotherapy with methotrexate and 6-mercaptopurine (6MP), for very high-risk B-cell acute lymphoblastic leukemia (ALL), presented with vomiting due to severe hypoglycemia with metabolic acidosis. While his laboratory values were concerning for a critically ill child, the patient was relatively well appearing. Hypoglycemia is a rare but serious side effect of 6MP with an unexpectedly variable presentation; therefore, a high index of suspicion is needed for its prompt detection and treatment. This patient also had severe metabolic acidosis, likely secondary to hypoglycemia, creating a serious clinical picture despite a well-appearing child. This example of incongruity between laboratory tests and clinical appearance adds nuance to the existing literature. Moreover, although 6MP-associated hypoglycemia is rare, it may be more prevalent than the literature suggests, as symptoms of hypoglycemia—nausea, vomiting, and somnolence—mirror common chemotherapy side effects. 6MP-induced hypoglycemia can be ameliorated with the addition of allopurinol to shunt metabolism in favor of the production of therapeutic metabolites over hepatotoxic metabolites. Additionally, a morning administration of 6MP and frequent snacks may also help to prevent hypoglycemia. Overall, this case adds to the literature of unusual reactions to 6MP including hypoglycemia in an older child without traditional risk factors.