Ruxolitinib for pediatric patients with treatment-naïve and steroid-refractory acute graft-versus-host disease (REACH4).

In REACH4 (NCT03491215), a phase 1/2, open-label, single-arm, multicenter study, the pharmacokinetics (PK), efficacy, and safety of ruxolitinib were evaluated in treatment-naïve and steroid-refractory pediatric patients with grade II-IV acute graft-versus-host disease (aGVHD; n=45). Ruxolitinib dosing was based on age and targeted the exposure in adults receiving 10 mg twice daily; group 1 (≥12 to <18 years) received 10 mg twice daily and preliminary starting doses for groups 2 (≥6 to <12 years) and 3 (≥2 to <6 years) were 5 mg twice daily and 4 mg/m2 twice daily, respectively. Phase 1 primary objective was to assess ruxolitinib PK parameters and define an age-appropriate recommended phase 2 dose (RP2D) for patients <12 years of age. Phase 2 primary objective was to measure the activity of ruxolitinib as assessed by overall response rate (ORR) at day 28; the key secondary objective was to assess the durable ORR at day 56. Ruxolitinib exposure was comparable across age groups; starting doses were confirmed as the RP2D. The median duration of ruxolitinib exposure was 3.8 months (range 0.3-11.2). ORR in all patients was 84.4% (90% confidence interval [CI], 72.8-92.5) at day 28, with a durable ORR at day 56 of 66.7% (90% CI, 53.4-78.2); high response rates were observed across age groups and in both treatment-naïve and steroid-refractory subgroups. Adverse events were consistent with those expected in ruxolitinib-treated patients with aGvHD (anemia, decreased neutrophil and leukocyte count). In pediatric patients with aGvHD, ruxolitinib showed clinically meaningful efficacy with no new safety signals.

A phase 3 randomized trial of mavorixafor, a CXCR4 antagonist, for WHIM syndrome.

ABSTRACT: We investigated efficacy and safety of mavorixafor, an oral CXCR4 antagonist, in participants with warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome, a rare immunodeficiency caused by CXCR4 gain-of-function variants. This randomized (1:1), double-blind, placebo-controlled, phase 3 trial enrolled participants aged ≥12 years with WHIM syndrome and absolute neutrophil count (ANC) ≤0.4 × 103/µL. Participants received once-daily mavorixafor or placebo for 52 weeks. The primary end point was time (hours) above ANC threshold ≥0.5 × 103/µL (TATANC; over 24 hours). Secondary end points included TAT absolute lymphocyte count ≥1.0 × 103/µL (TATALC; over 24 hours); absolute changes in white blood cell (WBC), ANC, and absolute lymphocyte count (ALC) from baseline; annualized infection rate; infection duration; and total infection score (combined infection number/severity). In 31 participants (mavorixafor, n = 14; placebo, n = 17), mavorixafor least squares (LS) mean TATANC was 15.0 hours and 2.8 hours for placebo (P < .001). Mavorixafor LS mean TATALC was 15.8 hours and 4.6 hours for placebo (P < .001). Annualized infection rates were 60% lower with mavorixafor vs placebo (LS mean 1.7 vs 4.2; nominal P = .007), and total infection scores were 40% lower (7.4 [95% confidence interval [CI], 1.6-13.2] vs 12.3 [95% CI, 7.2-17.3]). Treatment with mavorixafor reduced infection frequency, severity, duration, and antibiotic use. No discontinuations occurred due to treatment-emergent adverse events (TEAEs); no related serious TEAEs were observed. Overall, mavorixafor treatment demonstrated significant increases in LS mean TATANC and TATALC, reduced infection frequency, severity/duration, and was well tolerated. The trial was registered at www.clinicaltrials.gov as #NCT03995108.

Comparable outcomes of allogeneic peripheral blood versus bone marrow hematopoietic stem cell transplantation from a sibling donor for pediatric patients.

Traditionally, bone marrow (BM) has been preferred as a source of stem cells (SCs) in pediatric hematopoietic SC transplantation (HSCT); however, the use of peripheral blood SCs (PBSC) has recently increased. With advancing graft-versus-host disease (GVHD) prophylaxis, whether the BM is still a better SC source than PB in sibling donor HSCT remains controversial. Here, we compared the results of BM transplantation (BMT) and PBSC transplantation (PBSCT) in pediatric patients with malignant or non-malignant diseases receiving sibling HSCT using a total of 7.5 mg/kg of anti-thymocyte globulin (ATG). We retrospectively reviewed children who received HSCT from a sibling donor between 2005 and 2020 at Seoul National University Children's Hospital. Of the 86 patients, 40 underwent BMT, and 46 underwent PBSCT. Fifty- six patients had malignant diseases, whereas thirty patients had non-malignant diseases. All conditioning regimens comprised ATG. Busulfan-based myeloablative conditioning regimens were administered to patients with malignant diseases and approximately half of those with non-malignant diseases. The remaining half of the patients with non-malignant diseases were administered cyclophosphamide-based reduced- intensity conditioning regimens. According to studies conducted at our center, all BM donors received G-CSF before harvest to achieve early engraftment. In all 86 patients (47 males and 39 females), the median age at the time of HSCT was 11.4 (range, 0.7 - 24.6) years. The median follow-up period was 57.9 (range, 0.9-228.6) months, and the corresponding values for those with BM and PBSC were 77 (range, 2.4-228.6) months and 48.7 (range, 0.9-213.2) months, respectively. Engraftment failure occurred in one patient with BM and no patient with PBSC. The cumulative incidence of acute GVHD with grades II-IV was higher in PBSC (BM 2.5%, PBSC 26.1%, p = 0.002), but there was no significant difference in those with grades III-IV acute GVHD (BM 0%, PBSC 6.5%, p = 0.3703) and extensive chronic GVHD (BM 2.5%, PBSC 11.6%, p = 0.1004). There were no significant differences in treatment-related mortality (TRM) (BM 14.2%, PBSC 6.8%, p = 0.453), 5-year event-free survival (EFS) (BM 71.5%, PBSC 76.2%, p = 0.874), and overall survival (OS) rates (BM 80.8%, PBSC 80.3%, p = 0.867) between BM and PBSC in the univariate analysis. In the multivariate analysis, which included all factors with p < 0.50 in the univariate analysis, there was no significant prognostic factor for EFS or OS. There was no significant difference in the relapse incidence between BM and PBSC among patients with malignant diseases (BM 14.2%, PBSC 6.8%, p = 0.453). Additionally, there were no significant differences in the TRM, 5-year EFS, and OS rates between malignant and non-malignant diseases nor between the busulfan-based myeloablative regimen and reduced-intensity chemotherapy using cyclophosphamide. In this study, we showed no significant differences in EFS, OS, TRM, and GVHD, except for acute GVHD grades II-IV, between BMT and PBSCT from sibling donors, using ATG (a total of 7.5 mg/kg). Therefore, PB collection, which is less invasive for donors and less labor-intensive for doctors, could also be considered an acceptable SC source for sibling donor HSCT in children.

Successful Treatment of Refractory or Relapsed Hepatoblastoma With Autologous Hematopoietic Stem Cell Transplantation in Children.

BACKGROUND: The standard-risk hepatoblastoma has a good prognosis in children; however, refractory or relapsed (R/R) hepatoblastoma has a poor prognosis and high mortality rate. This study aimed to demonstrate the efficacy of high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HSCT) rescue in pediatric patients with R/R hepatoblastoma. METHODS: We retrospectively analyzed 6 pediatric patients with R/R hepatoblastoma who underwent autologous HSCT. The MEC conditioning regimen was used for all patients, comprising melphalan 140 mg/m 2 /day intravenously (IV) on day 7 and 70 mg/m 2 on day 6, etoposide 200 mg/m 2 IV on days 5 to 8, and carboplatin 400 mg/m 2 IV on days 5 to 8. One patient received a TopoThioCarbo regimen, comprising topotecan 2 mg/m 2 /day IV on days 4 to 8, thiotepa 300 mg/m 2 /day IV on days 6 to 8, and carboplatin 500 mg/m 2 /day IV on days 3 to 5, as the conditioning regimen for the first transplantation. This was followed by salvage chemotherapy for relapse, and the second transplantation was performed using MEC as the conditioning regimen. RESULTS: We report the retrospective results of 6 patients with a median age of 1.8 (range 0.4 to 10.2) years who had R/R hepatoblastoma and underwent autologous HSCT. The median follow-up period was 58 (range 28 to 113) months after diagnosis. The median stage at diagnosis was 2.0 (range 2 to 4). Two patients had lung metastases during diagnosis. The median initial alpha-fetoprotein level was 292,888 (range 28,831 to 2,406,942) ng/mL, and the median number of chemotherapy lines before autologous HSCT was 3.5 (range 2 to 7). The disease status before HSCT was complete remission (CR) for all patients. The engraftment rate was 100%. No treatment-related mortality was reported. The 3-year event-free survival and overall survival rates were 83.3% and 100%, respectively. One patient relapsed after the second HSCT and achieved CR after salvage chemotherapy. CONCLUSION: This study suggests autologous HSCT as an effective treatment in pediatric patients with R/R hepatoblastoma. Nevertheless, future large-scale prospective studies are warranted.

Shear wave elastography and dispersion imaging for hepatic veno-occlusive disease prediction after pediatric hematopoietic stem cell transplantation: a feasibility study.

BACKGROUND: Non-invasive imaging modalities are warranted for diagnosing and monitoring veno-occlusive disease because early diagnosis and treatment improve the prognosis. OBJECTIVE: To evaluate the usefulness of liver shear wave elastography (SWE) and shear wave dispersion (SWD) imaging in diagnosing and monitoring veno-occlusive disease in pediatric patients. MATERIALS AND METHODS: We conducted a prospective cohort study at a single tertiary hospital from March 2021 to April 2022. The study protocol included four ultrasound (US) sessions: a baseline US and three follow-up US after hematopoietic stem cell transplantation. Clinical criteria, including the European Society for Blood and Marrow Transplantation criteria, were used to diagnose veno-occlusive disease. We compared clinical factors and US parameters between the veno-occlusive disease and non-veno-occlusive disease groups. The diagnostic performance of US parameters for veno-occlusive disease was assessed by plotting receiver operating characteristic (ROC) curves. We describe temporal changes in US parameters before and after veno-occlusive disease diagnosis. RESULTS: Among the 38 participants (mean age 10.7 years), eight developed veno-occlusive disease occurring 17.0 ± 5.2 days after hematopoietic stem cell transplantation. Liver stiffness, as measured by SWE (15.0 ± 6.2 kPa vs. 5.8 ± 1.8 kPa; P<0.001), and viscosity, as assessed with SWD (17.7 ± 3.1 m/s/kHz vs. 14.3 ± 2.8 m/s/kHz; P=0.015), were significantly higher in the veno-occlusive disease group compared to the non-veno-occlusive disease group at the time of diagnosis. Liver stiffness demonstrated the highest area under the ROC (AUROC) curves at 0.960, with an optimal predictive value of >6.5 kPa, resulting in sensitivity and specificity of 100% and 83.3%, respectively. Viscosity demonstrated an AUROC of 0.783, with an optimal cutoff value of 13.9 m/s/kHz for predicting veno-occlusive disease, with a sensitivity of 100% and specificity of 53.3%, respectively. Liver stiffness increased with disease severity and decreased during post-treatment follow-up. CONCLUSION: SWE may be a promising technique for early diagnosis and severity prediction of veno-occlusive disease. Furthermore, liver viscosity assessed by SWD may serve as an additional marker of veno-occlusive disease.

Somatic uniparental disomy mitigates the most damaging EFL1 allele combination in Shwachman-Diamond syndrome.

Shwachman-Diamond syndrome (SDS; OMIM #260400) is caused by variants in SBDS (Shwachman-Bodian-Diamond syndrome gene), which encodes a protein that plays an important role in ribosome assembly. Recent reports suggest that recessive variants in EFL1 are also responsible for SDS. However, the precise genetic mechanism that leads to EFL1-induced SDS remains incompletely understood. Here we present 3 unrelated Korean SDS patients who carry biallelic pathogenic variants in EFL1 with biased allele frequencies, resulting from a bone marrow-specific somatic uniparental disomy in chromosome 15. The recombination events generated cells that were homozygous for the relatively milder variant, allowing for the evasion of catastrophic physiologic consequences. However, the milder EFL1 variant was still solely able to impair 80S ribosome assembly and induce SDS features in cell line and animal models. The loss of EFL1 resulted in a pronounced inhibition of terminal oligopyrimidine element-containing ribosomal protein transcript 80S assembly. Therefore, we propose a more accurate pathogenesis mechanism of EFL1 dysfunction that eventually leads to aberrant translational control and ribosomopathy.

CD19 chimeric antigen receptor T cell therapy in leukemia xenograft mouse: Anti-leukemic efficacy, kinetics, and 4-week single-dose toxicity.

CD19 Chimeric antigen receptor T (CAR-T) cell therapy has shown a promising response rate for relapsed/refractory B-cell malignancies. However, serious side effects such as cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome arose in early case reports. Though several preclinical and clinical studies of CAR-T cell therapy have been reported, there is a lack of toxicological assessments. This study was carried out as a preclinical assessment of CD19 CAR-T cell therapy, including the anti-leukemic efficacy, kinetics in peripheral blood, and 4-week single-dose toxicity evaluation in leukemia xenograft mice. Leukemia xenograft mice model was established by injecting 1.0 × 105 cells/mouse of luciferase-labeled human B cell acute lymphoblastic leukemia (B-ALL) cell line via the tail vein, and after 3 days, 2.0 or 4.0 × 106 cells/mouse of CD19 CAR-T cells were injected intravenously. CD19 CAR-T cells showed significant anti-leukemic efficacy, showing inhibition of tumor progression in the bioluminescence-based in-vivo imaging system. In the kinetics study using qPCR, CAR-T cells peaked in peripheral blood on day 60 in males and day 30 in females. In a 4-week single-dose toxicity study, CD19 CAR-T cell injected groups showed no mortality and toxicological signs, or changes in body weight, food/water consumption, hematology, clinical chemistry, organ weights, and histopathology compared to control groups. These results suggested that 4.0 × 106 cells/mouse of CD19 CAR-T cells were effective in B-ALL xenograft mice without serious side effects, so the no-observed adverse effect level (NOAEL) was estimated to be higher than 4.0 × 106 cells/mouse, under the condition examined in the current study.

Threshold of Quantitative Cytomegalovirus DNA PCR for Preemptive Treatment in Pediatric Hematopoietic Stem Cell Transplant Recipients.

BACKGROUND: Consensus cytomegalovirus (CMV) DNA viral load thresholds for intervention in hematopoietic stem cell transplant (HSCT) recipients have not been established, especially in children. This study aimed at obtaining viral load thresholds of CMV DNA to guide preemptive management in pediatric HSCT recipients. MATERIALS AND METHODS: A total of 465 blood samples from 177 children who received HSCT between 2015 and 2019 were included in a single center in Korea. The samples were analyzed for CMV infection by both antigenemia assay and quantitative DNA polymerase chain reaction. The 2 assay results were compared for the 233 samples which were collected when antiviral treatment has not been initiated. We determined the viral loads corresponding to the antigenemia of 5 pp65-positive cells/2×10 5 white blood cells (WBCs) as the level for initiating preemptive therapy. RESULTS: Sixty percent of the samples were collected within 100 days (39.7% in 0 to 50 d, 60.2% in 0 to 100 d) from the graft infusion. The correlation between CMV DNA viral load and CMV antigenemia level increased significantly after 50 days from the graft infusion ( r =0.71 vs. r =0.93, P <0.0001). The correlation was greater in the antiviral treatment-naive group than the treatment group ( r =0.75 vs. r =0.66, P <0.0001). Under receiver operating characteristic curve analysis of the treatment-naive group, the estimated threshold CMV DNA viral loads corresponding to 5 pp65-positive cells/2×10 5 WBCs was 898 IU/mL. CONCLUSIONS: The CMV DNA levels that corresponded to 5 pp65-positive cells/2×10 5 WBCs was 900 IU/mL in the HSCT group. The proposed viral load thresholds can be used to guide preemptive therapy in pediatric HSCT recipients, especially in the preengraftment period.

Clinical and Economic Impact of Pharmacists' Intervention on Care of Pediatric Hematology and Oncology Patients.

INTRODUCTION: Children with cancer may be one of the most vulnerable groups to drug-related adverse events because they possess characteristics of patients with cancer as well as pediatric patients. To evaluate the clinical and economic impact of pharmacists' intervention on the care of pediatric hematology and oncology patients in the inpatient and outpatient settings of a children's hospital. METHODS: The pharmacist-intervention records from 2017 were retrospectively reviewed. Intervention rate, type of drug-related problems, acceptance rate, and frequently involved drugs in pharmacist interventions were analyzed. One physician and one pharmacist evaluated the clinical significance of each intervention. A cost-benefit analysis was conducted from hospital and patient perspective. The benefit from cost savings by reducing the number of prescribed drugs that are disposed was estimated as the benefit from hospital perspective. The benefit from cost avoidance based on the potential to avoid an adverse drug event (ADE) was estimated as the benefit from patient perspective. The cost of reviewing prescriptions was estimated based on the pharmacists' salary and the time involved. RESULTS: In 2017, 2361 interventions were performed in 381 pediatric patients with cancer. The acceptance rate was 97.2%. More than half of the interventions were regarded as clinically "significant" (58.8%) and "very significant" (14.6%). The cost-benefit of US$28,705 was determined from hospital perspective, with a cost-benefit ratio of 1.45:1. The cost-benefit of US$35,611 was calculated from patient perspective, with a cost-benefit ratio of 1.55:1. CONCLUSIONS: Pharmacists' intervention in the care of hematology and oncology pediatric patients was effective in preventing clinically significant ADEs and had a positive economic impact on the health-care budget from both hospital and patient perspective.

Comparison of the clinical features and treatment outcomes of pilocytic astrocytoma in pediatric and adult patients.

PURPOSE: Pilocytic astrocytoma is a slow-growing tumor that predominantly develops in children, but has a broad age spectrum. A notable characteristic of pilocytic astrocytoma is that the tumor arises in diverse locations and the clinical course is not always benign. Therefore, it is necessary to elucidate the clinical spectrum of the disease and analyze the relevant prognostic factors. METHODS: Demographic and treatment-related factors were retrospectively reviewed in a cohort of 254 patients with histologically confirmed pilocytic astrocytoma. Clinical features were compared between the pediatric group (N = 208; age < 18 years) and the adult group (N = 46; age ≥ 18 years). Cox regression analysis was performed to identify relevant prognostic factors. RESULTS: There was no difference in progression-free survival (PFS) between the pediatric and adult groups (p = 0.36); however, patients under 8 years of age exhibited worse PFS (p < 0.01). Leptomeningeal seeding at diagnosis and pilomyxoid histology was observed only in pediatric patients. In the pediatric group, nine patients experienced recurrence after complete resection. Increasing age (hazard ratio (HR) = 0.89, p < 0.01) and adjuvant therapy (HR = 0.32, p < 0.01) were protective factors against tumor progression. In the adult group, no progression occurred after complete resection. Age and adjuvant therapy were not significant factors in the adult group. CONCLUSION: Pilocytic astrocytoma presents with a diverse clinical spectrum. Complete resection is of utmost importance, and appropriate adjuvant treatment is recommended if complete resection cannot be achieved. Children with younger age are associated with more aggressive tumors, and recurrence may occur even after complete resection.

International retrospective study of allogeneic hematopoietic cell transplantation for activated PI3K-delta syndrome.

BACKGROUND: Activated phosphoinositide 3-kinase delta syndrome (APDS) is a combined immunodeficiency with a heterogeneous phenotype considered reversible by allogeneic hematopoietic cell transplantation (HCT). OBJECTIVES: This study sought to characterize HCT outcomes in APDS. METHODS: Retrospective data were collected on 57 patients with APDS1/2 (median age, 13 years; range, 2-66 years) who underwent HCT. RESULTS: Pre-HCT comorbidities such as lung, gastrointestinal, and liver pathology were common, with hematologic malignancy in 26%. With median follow-up of 2.3 years, 2-year overall and graft failure-free survival probabilities were 86% and 68%, respectively, and did not differ significantly by APDS1 versus APDS2, donor type, or conditioning intensity. The 2-year cumulative incidence of graft failure following first HCT was 17% overall but 42% if mammalian target of rapamycin inhibitor(s) (mTORi) were used in the first year post-HCT, compared with 9% without mTORi. Similarly, 2-year cumulative incidence of unplanned donor cell infusion was overall 28%, but 65% in the context of mTORi receipt and 23% without. Phenotype reversal occurred in 96% of evaluable patients, of whom 17% had mixed chimerism. Vulnerability to renal complications continued post-HCT, adding new insights into potential nonimmunologic roles of phosphoinositide 3-kinase not correctable through HCT. CONCLUSIONS: Graft failure, graft instability, and poor graft function requiring unplanned donor cell infusion were major barriers to successful HCT. Post-HCT mTORi use may confer an advantage to residual host cells, promoting graft instability. Longer-term post-HCT follow-up of more patients is needed to elucidate the kinetics of immune reconstitution and donor chimerism, establish approaches that reduce graft instability, and assess the completeness of phenotype reversal over time.

Avelumab in paediatric patients with refractory or relapsed solid tumours: dose-escalation results from an open-label, single-arm, phase 1/2 trial.

BACKGROUND: We report dose-escalation results from an open-label, phase 1/2 trial evaluating avelumab (anti-PD-L1) in paediatric patients with refractory/relapsed solid tumours. METHODS: In phase 1, patients aged < 18 years with solid (including central nervous system [CNS]) tumours for which standard therapy did not exist or had failed were enrolled in sequential cohorts of 3-6 patients. Patients received avelumab 10 or 20 mg/kg intravenously every 2 weeks. Primary endpoints were dose-limiting toxicities (DLTs) and grade ≥ 3 treatment-emergent adverse events (AEs). RESULTS: At data cut-off (27 July 2021), 21 patients aged 3-17 years had received avelumab 10 mg/kg (n = 6) or 20 mg/kg (n = 15). One patient had three events that were classified as a DLT (fatigue with hemiparesis and muscular weakness associated with pseudoprogression; 20 mg/kg cohort). Grade ≥ 3 AEs occurred in five (83%) and 11 (73%) patients in the 10 and 20 mg/kg cohorts, respectively, and were treatment-related in one patient (7%; grade 3 [DLT]) in the 20 mg/kg cohort. Avelumab exposure in paediatric patients receiving 20 mg/kg dosing, but not 10 mg/kg, was comparable or higher compared with approved adult dosing (10 mg/kg or 800 mg flat dose). No objective responses were observed. Four patients with CNS tumours (20 mg/kg cohort) achieved stable disease, which was ongoing in two patients with astrocytoma at cut-off (for 24.7 and 30.3 months). CONCLUSION: In paediatric patients with refractory/relapsed solid tumours, avelumab monotherapy showed a safety profile consistent with previous adult studies, but clinical benefits were limited.

Outcomes of intracranial non-germinomatous germ cell tumors: a retrospective Asian multinational study on treatment strategies and prognostic factors.

PURPOSE: Non-germinomatous germ cell tumors (NGGCTs) are rare pediatric conditions. This multicenter study using Asian multinational patient data investigated treatment outcomes and prognostic factors for NGGCTs. METHODS: Medical records of 251 patients with NGGCTs treated from 1995 to 2015 were retrospectively analyzed from participating centers in Asian countries (Korea, Taiwan, Singapore, and Japan). RESULTS: The median follow up was 8.5 years (95% CI 7.8-9.9). In the total cohort, 5-year event-free survival (EFS) and overall survival (OS) rates were 78.2% and 85.4%, respectively. In 17.9% of the patients, diagnosis was determined by tumor markers alone (alpha-fetoprotein ≥ 10 ng/mL (Korea) or > 25 ng/mL (Taiwan and Singapore), and/or ß-human chorionic gonadotropin (ß-hCG) ≥ 50 mIU/mL). Patients with immature teratomas and mature teratomas comprised 12.0% and 8.4%, respectively. The 5-year EFS rate was higher in patients with histologically confirmed germinoma with elevated ß-hCG (n = 28) than those in patients with malignant NGGCTs (n = 127). Among malignant NGGCTs, patients with choriocarcinoma showed the highest 5-year OS of 87.6%, while yolk sac tumors showed the lowest OS (68.8%). For malignant NGGCT subgroups, an increase in serum ß-hCG levels by 100 mIU/mL was identified as a significant prognostic factor associated with the EFS and OS. CONCLUSION: Our result shows excellent survival outcomes of overall CNS NGGCT. However, treatment outcome varied widely across the histopathologic subgroup of NGGCT. Hence, this study suggests the necessity for accurate diagnosis by surgical biopsy and further optimization of diagnosis and treatment according to the histopathology of NGGCTs. Future clinical trials should be designed for individualized treatments for different NGGCTs subsets.

Outbreak of COVID-19 among children and young adults in a cancer centre daycare unit.

Nosocomial transmission of COVID-19 among immunocompromised hosts can have a serious impact on COVID-19 severity, underlying disease progression and SARS-CoV-2 transmission to other patients and healthcare workers within hospitals. We experienced a nosocomial outbreak of COVID-19 in the setting of a daycare unit for paediatric and young adult cancer patients. Between 9 and 18 November 2020, 473 individuals (181 patients, 247 caregivers/siblings and 45 staff members) were exposed to the index case, who was a nursing staff. Among them, three patients and four caregivers were infected. Two 5-year-old cancer patients with COVID-19 were not severely ill, but a 25-year-old cancer patient showed prolonged shedding of SARS-CoV-2 RNA for at least 12 weeks, which probably infected his mother at home approximately 7-8 weeks after the initial diagnosis. Except for this case, no secondary transmission was observed from the confirmed cases in either the hospital or the community. To conclude, in the day care setting of immunocompromised children and young adults, the rate of in-hospital transmission of SARS-CoV-2 was 1.6% when applying the stringent policy of infection prevention and control, including universal mask application and rapid and extensive contact investigation. Severely immunocompromised children/young adults with COVID-19 would have to be carefully managed after the mandatory isolation period while keeping the possibility of prolonged shedding of live virus in mind.

Hemophagocytic lymphohistiocytosis associated with parvovirus B19-induced aplastic crisis in a hereditary spherocytosis patient: A case report and literature review.

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of pathologic immune activation. It occurs because of severe inflammation due to uncontrolled proliferation of activated lymphocytes and histiocytes, characterized by the production of excessive levels of cytokines. Virus-associated HLH is a well-known entity, and parvovirus B19 is one of the common causes. Parvovirus B19 can also affect blood cell lineages. Therefore, HLH may be accompanied by several diseases such as cytopenia, aplastic anemia, and myelodysplastic syndrome. Herein, we report the case of a patient with hereditary spherocytosis who was diagnosed with parvovirus B19-induced HLH and aplastic crisis. A 7-year-old girl presented to our hospital with fever, pleural effusion, pancytopenia, hepatosplenomegaly, and hypotension. A bone marrow biopsy was performed under the suspicion of HLH, which revealed hemophagocytes. The diagnostic criteria for HLH were met, and prompt chemoimmunotherapy was initiated considering the clinically unstable situation. Her health improved rapidly after initiating treatment. Further study revealed that she had hereditary spherocytosis, and parvovirus B19 had caused aplastic crisis and HLH. The patient's clinical progress was excellent, and chemoimmunotherapy was reduced and discontinued at an early stage. This case shows that aplastic crisis and HLH can coexist with parvovirus B19 infection in patients with hereditary spherocytosis. Although the prognosis was good in this case of HLH caused by parvovirus B19, early detection and active treatment are essential.

Phase 2 study of nilotinib in pediatric patients with Philadelphia chromosome-positive chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is rare in children and accounts for ≤15% of all myeloid leukemia cases. When we initiated this study with nilotinib, imatinib was the only tyrosine kinase inhibitor indicated for pediatric patients with Philadelphia chromosome-positive (Ph+) CML in chronic phase (CP); alternative treatment options were needed, particularly for patients who developed resistance or intolerance (R/I) to imatinib. This phase 2 study enrolled pediatric patients with either Ph+ CML-CP R/I to imatinib or dasatinib or newly diagnosed Ph+ CML-CP. Data presented are from analyses with minimum follow-up of up to 24 cycles (1 cycle is 28 days). Fifty-nine patients with Ph+ CML-CP were enrolled, and 58 were treated (R/I, n = 33; newly diagnosed, n = 25). Major molecular response (MMR) rate at cycle 6 in the R/I cohort was 39.4% (primary end point); 57.6% of patients achieved or maintained MMR and 81.8% achieved or maintained complete cytogenetic response (CCyR) by 24 cycles. In patients with newly diagnosed disease, rates of MMR by cycle 12 and CCyR at cycle 12 were 64.0% each (primary end points); by cycle 24, cumulative MMR and CCyR rates were 68.0% and 84.0%, respectively. The safety profile of nilotinib in pediatric patients was generally comparable with the known safety profile in adults, although cardiovascular events were not observed in this study, and hepatic laboratory abnormalities were more frequent; no new safety signals were identified. In summary, nilotinib demonstrated efficacy and a manageable safety profile in pediatric patients with Ph+ CML-CP. This trial was registered at www.clinicaltrials.gov as #NCT01844765.

A multicenter report on the safety and efficacy of plerixafor based stem cell mobilization in children with malignant disorders.

BACKGROUND: Pleraxifor for peripheral blood stem cell (PBSC) mobilization in children with malignancies is often given following failure of standard mobilization (SM) rather than as a primary mobilizing agent. STUDY DESIGN AND METHODS: In this retrospective multicenter study, we report the safety of plerixafor-based PBSC mobilization in children with malignancies and compare outcomes between patients who received plerixafor upfront with SM (Group A) with those who received plerixafor following failure of SM (Group B). In the latter pleraxifor was given either following a low peripheral blood (PB) CD34 (<20 cells/cu.mm) (Group B1) or as a second collection process due to an unsuccessful yield (CD34 + < 2 × 106 /kg) (Group B2) following failed SM and first apheresis attempts. RESULTS: The study cohort (n = 47) with a median age of 8 (range 0.6-21) year, comprised 19 (40%) Group A and 28 (60%) Group B patients (B1 = 12 and B2 = 16). Pleraxifor mobilization was successful in 87.2% of patients, similar between Groups A and B (84.2% vs 89.2%) and resulted in a median 4-fold increase in PB CD34. Median number of apheresis attempts was 2 in Groups A and B1 but 4 in Group B2. In Group B2, median total CD34+ yield post-plerixafor was 9-fold higher than after SM (P = .0013). Mild to moderate transient adverse events affected 8.5% of patients. Among patients who proceeded to autologous transplant (n = 39), all but one engrafted. CONCLUSION: Plerixafor-based PBSC collection was safe and effective in our cohort and supports consideration as a primary mobilizing agent in children with malignancies.

Combination Therapy With Chemotherapy, Donor Lymphocyte Infusion With Concurrent Blinatumomab in Relapsed/Refractory Acute Precursor B-Lymphoblastic Leukemia.

The therapeutic approach for relapsed/refractory acute lymphoblastic leukemia (ALL) remains to be a challenge. The patient was diagnosed as B-cell ALL at 6 months of age and relapsed for the second time following repeat allogeneic hematopoietic stem cell transplantation (one after first complete remission [CR1] and the other after CR2). During blinatumomab monotherapy, he developed an extramedullary relapse. Finally, the combined therapy with clofarabine, donor lymphocyte infusion, and blinatumomab induced CR of the bone marrow and extramedullary relapse. Unfortunately, the patient developed central nervous system relapse, however, this case showed a promising potential for combination therapy with clofarabine, donor lymphocyte infusion, and blinatumomab in relapsed/refractory B-cell ALL.

Stage IV Classical Hodgkin Lymphoma-type Posttransplant Lymphoproliferative Disorder in a Pediatric Liver Transplant Patient: A Case Report and Review of the Literature.

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous group of diseases with abnormal proliferation of lymphoid tissue and classical Hodgkin lymphoma (CHL) type PTLD is a very rare subtype. We describe a successfully diagnosed and treated CHL-PTLD stage IV pediatric patient, 8 years after liver transplantation. The patient was treated with standard CHL (Children's Cancer Group 5942 group 3) chemotherapy, rituximab and reduction of immunosuppressant. The patient remains in complete remission after 3 years with stable graft function. To our best knowledge, this is the first pediatric case report of a successfully treated stage IV CHL-PTLD after a liver transplant.

Erratum: Correction of Affiliations in the Article "Clinical Characteristics and Treatment Outcomes in Children, Adolescents, and Young-adults with Hodgkin's Lymphoma: a KPHOG Lymphoma Working-party, Multicenter, Retrospective Study".

This corrects the article on p. e393 in vol. 35, PMID: 33258329.