Differential impact of asparaginase discontinuation on outcomes of children with T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma

BACKGROUND

Asparaginase is essential for treating T-cell acute lymphoblastic leukemia (T-ALL). Despite the ongoing debate on whether T-ALL and T-cell lymphoblastic lymphoma (T-LBL) are the same disease entity or two distinct diseases, patients with T-LBL often receive the same or similar treatment protocols as those with T-ALL.

METHODS

The outcomes of patients with or without L-asparaginase discontinuation were retrospectively analyzed among four national protocols: Japan Association of Childhood Leukemia Study (JACLS) ALL-02 and ALL-97 for T-ALL and Japanese Pediatric Leukemia/Lymphoma Study Group ALB-NHL03 and JACLS NHL-98 for T-LBL. The hazard ratio (HR) was calculated with the Cox regression model by considering L-asparaginase discontinuation as a time-dependent variable.

RESULTS

In total, 199 patients with T-ALL, and 133 patients with T-LBL were included. L-asparaginase discontinuation compromised event-free survival (EFS) of T-ALL patients (ALL-02: HR 3.32, 95% confidence interval [CI] 1.40-7.90; ALL-97: HR 3.39, 95%CI 1.19-9.67). Conversely, EFS compromise was not detected among T-LBL patients (ALB-NHL03: HR 1.39, 95%CI 0.41-4.68; NHL-98: HR 0.92, 95%CI 0.11-7.60).

CONCLUSION

The effects of L-asparaginase discontinuation differed between T-ALL and T-LBL. We assume that the differential impact results from (1) the inherent differential response to L-asparaginase between them and/or (2) a less stringent assessment of early treatment response in T-LBL than in T-ALL. Given the poor salvage rate of refractory or relapsed T-ALL and T-LBL, optimization of the frontline therapy is critical, and the current study provides a new suggestion for further treatment modifications. However, larger studies in contemporary intensified treatment protocols are required.

Magnesium supplementation therapy to prevent cisplatin-induced acute nephrotoxicity in pediatric cancer: a randomized phase-2 trial

BACKGROUND

The present study aimed to examine the effect of magnesium (Mg) supplementation on cisplatin-induced nephrotoxicity (CIN) in pediatric cancer patients.

METHODS

The present phase-2, open-label, multicenter, randomized controlled trial enrolled patients aged less than 20 years who were scheduled to receive cisplatin-containing chemotherapy and randomly allocated them at a ratio of 1:1 to a Mg supplementation arm with even-numbered chemotherapy courses (arm AB) or another arm with odd-numbered courses (arm BA). Analysis objects were reconstructed into two groups depending on whether the chemotherapy course had Mg supplementation (group B) or not (group A). The primary outcome was the proportion of chemotherapy courses resulting in elevated serum creatinine per chemotherapy course. The secondary outcomes included efficacies evaluated using other biomarkers and the safety of the Mg supplementation.

RESULTS

Twenty-eight patients were randomly allocated to either group (16 to arm AB and 12 to arm BA). The baseline characteristics of the groups were similar. There was no significant difference in the proportion of courses with increased serum creatinine between the groups (group A: 10% vs. group B: 6%; P = 0.465) nor was any significant difference observed in other biomarkers during any chemotherapy course. The Mg value during chemotherapy was significantly higher in group B than that in group A. No adverse events related to magnesium administration were observed.

CONCLUSIONS

The study design, which treated a single chemotherapy course as a study object, failed to detect a statistically significant benefit of Mg supplementation for preventing CIN in pediatric cancer patients.

TRIAL REGISTRATION

JRCT ( https://jrct.niph.go.jp/ ) Identifier UMIN000029215 jRCTs031180251. UMIN-CTR ( http://www.umin.ac.jp/icdr/index.html ) Identifier UMIN000029215.

Clinical and Diagnostic Utility of Genomic Profiling for Digestive Cancers: Real-World Evidence from Japan

The usefulness of comprehensive genomic profiling (CGP) in the Japanese healthcare insurance system remains underexplored. Therefore, this large-scale study aimed to determine the usefulness of CGP in diagnosing digestive cancers. Patients with various cancer types recruited between March 2020 and October 2022 underwent the FoundationOne® CDx assay at the Keio PleSSision Group (19 hospitals in Japan). A scoring system was developed to identify potentially actionable genomic alterations of biological significance and actionable genomic alterations. The detection rates for potentially actionable genomic alterations, actionable genomic alterations, and alterations equivalent to companion diagnosis (CDx), as well as the signaling pathways associated with these alterations in each digestive cancer, were analyzed. Among the 1587 patients, 547 had digestive cancer. The detection rates of potentially actionable genomic alterations, actionable genomic alterations, and alterations equivalent to CDx were 99.5%, 62.5%, and 11.5%, respectively. APC, KRAS, and CDKN2A alterations were frequently observed in colorectal, pancreatic, and biliary cancers, respectively. Most digestive cancers, except esophageal cancer, were adenocarcinomas. Thus, the classification flowchart for digestive adenocarcinomas proposed in this study may facilitate precise diagnosis. CGP has clinical and diagnostic utility in digestive cancers.

Genome-wide assessment of genetic risk loci for childhood acute lymphoblastic leukemia in Japanese patients

Not available.

Reduced-intensity allogenic transplantation for children and adolescents with Philadelphia chromosome-positive acute lymphoblastic leukemia

Survival rates of patients with Philadelphia chromosome-positive ALL (Ph+ALL) have improved considerably with the introduction of tyrosine kinase inhibitors (TKI); however, hematopoietic stem cell transplantation (HSCT) continues to play an important role. Reduced-intensity conditioning (RIC) regimens have been widely applied particularly for older patients, but their validity for children and adolescents with Ph+ALL has not been investigated. In this study, data from patients receiving HSCT for de novo Ph+ALL in first or second remission at ages younger than 25 years and with a history of pre-HSCT TKI therapy were retrospectively collected through the nationwide registry in Japan. In 265 patients who received myeloablative conditioning (MAC) and 33 patients receiving RIC, 5-year leukemia-free survival (LFS) rates were 67.3% and 79.8%, respectively (p = 0.142). Multivariate analysis of LFS, focusing on patients with good performance status, identified RIC as a significant prognostic factor for LFS (hazard ratio 0.32, p = 0.032), as well as older age, higher leukocyte count at diagnosis, and disease with additional chromosomal abnormalities. These trends were similar when we focused on patients who received prophylactic post-HSCT TKI treatment, as 5-year LFS was 81.0% for MAC and 84.4% for RIC (p = 0.748). In summary, HSCT with RIC regimen showed at least comparable LFS to HSCT with MAC regimen, and RIC was an independent favorable prognostic factor on multivariate analysis adjusting potential prognostic factors. While patient numbers were limited, our data suggest that RIC may be safely applied in this group, particularly combined with prophylactic post-HSCT TKI maintenance therapy.

Treatment of Pediatric Acute Lymphoblastic Leukemia: A Historical Perspective

Acute lymphoblastic leukemia (ALL) is the most common disease in pediatric oncology. The history of developmental therapeutics for ALL began in the 1960s with the repetition of "unreliable" medical interventions against this lethal disease. By the 1990s, the development of multi-agent chemotherapy and various types of supportive care rendered ALL treatable. Highly sophisticated, molecular, diagnostic techniques have enabled highly accurate prediction of the relapse risk, and the application of risk-adapted treatments has increased the survival rate in the standard-risk group to nearly 100% in most European nations and North America. Incorporation of state-of-the-art, molecularly targeted agents and novel treatments, including cell and immunotherapy, is further improving outcomes even in the high-risk group. On the other hand, the financial burden of treating children with ALL has increased, imperiling the availability of these diagnostic and treatment strategies to patients in low- and middle-income countries (LMICs). The fundamental treatment strategy, consisting of corticosteroid and classical cytotoxic therapy, has achieved fairly good outcomes and should be feasible in LMICs as well. The present review will discuss the history of developmental therapeutics for childhood ALL in various countries through an extensive literature review with the aim of proposing a model for a treatment backbone for pediatric ALL. The discussion will hopefully benefit LMICs and be useful as a base for future clinical trials of novel treatments.

Challenges to Widespread Use of Fertility Preservation Facilities for Pediatric Cancer Patients in Japan

Purpose: Although fertility preservation for pediatric cancer patients is becoming more widespread in Japan, some facilities do not provide sufficient information regarding fertility. This study aimed to elucidate the problems pertaining to the lack of information about fertility among patients. Methods: Based on a 2020 survey, seminars addressing fertility preservation were held from the Designated Pediatric Cancer Care Hospitals in each of the seven blocks in Japan to their partner hospital (pediatric cancer hospitals). The seminar consisted of lectures and group discussions, and a questionnaire was also administered after each seminar. Results: In the group discussions, a lack of explanations to patients and explanatory materials for children were cited as issues by many facilities. The survey results revealed a lack of material explaining fertility preservation and a lack of knowledge among health care providers. There were also many requests to use the patient explanation videos presented at the seminar. Conclusion: The results indicate that further education for health care providers by seminar and other sources and enhancement of explanatory materials are important for fertility preservation in pediatric cancer hospitals in Japan.

Retinoid Therapy for Neuroblastoma: Historical Overview, Regulatory Challenges, and Prospects

Retinoids are vitamin A derivatives and include trans-retinoic acid, isotretinoin, tamibarotene, and bexarotene, all of which are currently available for clinical use. The clinical development of retinoid therapy for neuroblastoma has a history spanning more than four decades. The most promising agent is isotretinoin, which can contribute to improving event-free survival in patients with high-risk neuroblastoma by approximately 10% when administered over six months as maintenance therapy. Although isotretinoin is regarded as an essential component in the standard clinical management of high-risk neuroblastoma, its use for this purpose in the US and EU is off-label. To promote isotretinoin use in Japan as a treatment for neuroblastoma, our clinical research team is planning to launch an investigator-initiated, registration-directed clinical trial. The present review article discusses the basic science behind retinoid therapy, pre-clinical/clinical evidence on neuroblastoma, the concept of the proposed clinical trial, and prospects for this therapy.

Inter-reporter differences in symptom burdens in Japanese children with cancer

BACKGROUND

Recent studies about inter-reporter differences and patient-reported outcomes (PROs) in childhood cancer from Western countries showed that caregiver proxy reports tend to overestimate symptom burdens in comparison with children's self-reports. However, the results from Western countries may not be generalizable to Asian countries.

METHODS

This paper is a secondary analysis of a validation study of the Japanese pediatric version of the Memorial Symptom Assessment Scale including 88 dyads of children aged 7-12 years and 74 dyads of children aged 13-18 years and their caregivers. The study assessed the inter-reporter differences of eight and 31 symptom burdens calculated as symptom scores in children aged 7-12 years and 13-18 years, respectively, and the association between inter-reporter differences and the characteristics of children and caregivers.

RESULTS

The majority of children and caregivers scored equally at the dyadic level for almost all symptoms. However, 37.5% of symptoms in children aged 7-12 years and 10.0% of symptoms in children aged 13-18 years showed significant inter-reporter differences, suggesting a general tendency of caregivers to underestimate their children's symptom burden. The caregiver's age was the characteristic most frequently associated with magnitude of inter-reporter differences.

CONCLUSIONS

Caregiver proxy reports may be a reliable source of PROs in Japanese children with cancer, as self-reported and caregiver proxy-reported symptom burdens were generally concordant. However, as some significant inter-reporter differences were observed, an effort should be made within the medical community to evaluate the parent-child relationship to minimize inter-reporter differences and achieve better symptom management.

Adverse Events in Pediatric Inpatients: The Japan Adverse Event Study

OBJECTIVES

Adverse events (AEs) represent an important cause of morbidity and mortality for pediatric inpatients; however, reports on their epidemiology in pediatrics, especially outside Western countries, are scarce. We investigated the incidence and nature of AEs in pediatric inpatients in Japan.

METHODS

Trained pediatrician and pediatric nurses reviewed all medical documents of 1126 pediatric inpatients in 2 tertiary care teaching hospitals in Japan, and potential incidents were collected with patients' characteristics. Age was categorized into 6 groups (neonates, infants, preschoolers, school-aged children, teenagers, and over-aged pediatric patients), and medical care when potential incidents occurred was classified into drug, operation, procedure/examinations, nursing, management, and judgment. Physician reviewers independently evaluated all collected incidents into AEs, potential AEs, medical errors, and exclusions and assessed their severity and preventability.

RESULTS

A total of 1126 patients with 12,624 patient-days were enrolled, and 953 AEs, with an incidence of 76 (95% confidence interval, 71-80) per 1000 patient-days, were identified. Preventable AEs accounted for 23% (218/953) of AEs. The incidence of AEs tended to decrease with increasing age. The proportion of AEs that were preventable was highest in neonates (40%), and this proportion decreased as children aged. Both judgment and management-related AEs were considered preventable AEs, and judgment-related AEs were more severe AEs than no-judgment-related AEs; 43% were life-threatening.

CONCLUSIONS

Adverse events were common in Japanese pediatric inpatients, and their preventability and severity varied considerably by age category and medical care. Further investigation is needed to address which strategies might most improve pediatric patient safety.

Allogeneic Hematopoietic Cell Transplantation for Juvenile Myelomonocytic Leukemia with a Busulfan, Fludarabine, and Melphalan Regimen: JPLSG JMML-11

Juvenile myelomonocytic leukemia (JMML), which is classified as a myelodysplastic/myeloproliferative neoplasm, is a rare hematologic malignancy of childhood. Most patients with JMML require allogeneic hematopoietic cell transplantation (HCT) as a curative therapy. A Japanese retrospective analysis demonstrated favorable outcomes for a busulfan (BU) + fludarabine (FLU) + melphalan (MEL) regimen, with an overall survival (OS) of 72% and an event-free survival (EFS) of 53%. To further validate the efficacy and safety of this regimen, the Japan Pediatric Leukemia/Lymphoma Study Group (JPLSG) conducted a nationwide prospective study, JMML-11. Between July 2011 and June 2017, 28 patients with newly diagnosed JMML were enrolled in JMML11. Low-dose chemotherapy for tumor control before HCT was recommended, and patients treated with AML-type chemotherapy and azacitidine were excluded. The conditioning regimen comprised i.v. BU, 16 doses administered every 6 h, with dose adjustment based on pharmacokinetic (PK) studies on days -11 to -8; FLU, 30 mg/m2/day or 1 mg/kg/day for patients <10 kg or age <1 year on days -7 to -4; and MEL, 90 mg/m2/day or 3 mg/kg/day for patients <10 kg or <1 year on days -3 to -2. The donor was selected by the physician in charge. A family donor was available for 7 patients (3 HLA-matched siblings, 3 HLA-1-antigen mismatched parents, and 1 haploidentical father). Overall, 21 patients received grafts from unrelated donors, including 8 HLA-matched donors and 13 HLA-mismatched donors. The graft source was related bone marrow (BM) for 7 patients, unrelated BM for 14 patients, and unrelated cord blood for 7 patients. Neutrophil engraftment was achieved in 21 of 28 patients (75%), with a median of 20.5 days (range, 11 to 39 days) after transplantation. The 3-year OS, 3-year EFS, 3-year relapse rate, and 3-year transplantation-related mortality were 63% (95% confidence interval [CI], 42% to 78%), 52% (95% CI, 32% to 69%), 18% (95% CI, 6% to 34%), and 21% (95% CI, 9% to 38%), respectively. WBC count before the conditioning regimen (≥7.0 × 109/L) was significantly associated with inferior EFS and OS. Body surface area ≥.5 m2, spleen size <4 cm before conditioning, and HLA-matched unrelated BM donors were significantly associated with better OS. Adverse effects related to the conditioning regimen included febrile neutropenia (86%), diarrhea (39%), hypoxemia (21%), and mucositis (18%). BU-associated toxicity, including sinusoidal obstruction syndrome (SOS) and thrombotic microangiopathy (TMA), occurred in 7 patients (25%; SOS, n = 6; TMA, n = 2). Retrospective analysis of PK data after the first BU dose in 23 patients, including 6 with SOS and 17 without SOS, did not show significant differences between groups. The JMML-11 study confirms the positive results of previous retrospective analyses. BU+FLU+MEL might become a standard conditioning regimen for patients with JMML.

Role of Peer Support in Posttraumatic Growth Among Adolescent and Young Adult Cancer Patients and Survivors

Purpose: Adolescents and young adults (AYA) who undergo cancer treatment sometimes report posttraumatic growth (PTG). Although the importance of peer support has been suggested, its association with PTG, especially its five distinct domains, needs to be investigated further in AYA cancer survivors. The present study examined the role of demographics and peer support in PTG among AYA cancer patients and survivors. Methods: The present, multicenter, cross-sectional, web-based study enrolled AYA cancer patients and survivors (median age: 28 years). Of 549 AYA patients recruited, 212 from 11 cancer centers and 12 cancer patient communities agreed to participate by completing a self-reported measure of PTG (Extended Version of the Posttraumatic Growth Inventory-Japanese) and providing information about their diagnosis, treatment, peer support (affiliation with an AYA patient community or friendship with other AYA patients), and social status. Multiple regression analysis was used to identify significant correlations overall and in the five PTG domains. Results: PTG was positively associated with male sex, having a confidant, and friendship with other AYA patients, and negatively associated with cranial radiation. Friendship with other AYA patients was positively associated with four of the five PTG subscales. For the five subscale scores, "cranial radiation" was negatively associated with "relating to others"; "belonging to a religion" was positively associated with "spiritual change"; and "having a confidant" was positively associated with "relating to others" and "new possibility." Conclusion: "Having a confidant" and "friendship with other AYA patients" were positively associated with PTG. Psychosocial interventions mobilizing peer support may contribute to promoting PTG in AYA patients. UMIN000035439.

Rare TCF3 variants associated with pediatric B cell acute lymphoblastic leukemia

Germline genetic variants influence development of pediatric B cell acute lymphoblastic leukemia (B-ALL). Genome-wide association studies (GWAS) have identified several pediatric B-ALL susceptibility loci. IKZF1 and PAX5, transcription factors involved in B cell development, have been reported as susceptibility genes for B-ALL development. Therefore, we hypothesized that rare variants of genes involved in B cell development would be candidate susceptibility loci for pediatric B-ALL. Thus, we sequenced TCF3, a key transcription factor gene involving in B cell development. Saliva DNA from 527 pediatric patients with pediatric B-ALL in remission who were registered with the Tokyo Children's Cancer Study Group (TCCSG) were examined. As a TCF3 gene-based evaluation, the numbers of rare deleterious germline TCF3 sequence variants in patients with pediatric B-ALL were compared with those in cancer-free individuals using data in public databases. As a TCF3 single-variant evaluation, the frequencies of rare deleterious germline TCF3 sequence variants in patients with pediatric B-ALL were also compared with those in control data. TCF3 gene-based analysis revealed significant associations between rare deleterious variants and pediatric B-ALL development. In addition, TCF3 variant-based analysis showed particularly strong association between variant rs372168347 (three in 521 TCCSG and three in the 15780 gnomAD whole genome analysis cohort, p = 0.0006) and pediatric B-ALL development. TCF3 variants are known to influence B cell maturation and may increase the risk of preleukemic clone emergence.

Prevalence of pathogenic variants in cancer-predisposing genes in second cancer after childhood solid cancers

BACKGROUND

Second malignant neoplasms (SMNs) are one of the most severe late complications after pediatric cancer treatment. However, the effect of genetic variation on SMNs remains unclear. In this study, we revealed germline genetic factors that contribute to the development of SMNs after treatment of pediatric solid tumors.

METHODS

We performed whole-exome sequencing in 14 pediatric patients with SMNs, including three brain tumors.

RESULTS

Our analysis revealed that five of 14 (35.7%) patients had pathogenic germline variants in cancer-predisposing genes (CPGs), which was significantly higher than in the control cohort (p < 0.01). The identified genes with variants were TP53 (n = 2), DICER1 (n = 1), PMS2 (n = 1), and PTCH1 (n = 1). In terms of the type of subsequent cancer, leukemia and multiple episodes of SMN had an exceptionally high rate of CPG pathogenic variants. None of the patients with germline variants had a family history of SMN development. Mutational signature analysis showed that platinum drugs contributed to the development of SMN in three cases, which suggests the role of platinum agents in SMN development.

CONCLUSIONS

We highlight that overlapping effects of genetic background and primary cancer treatment contribute to the development of second cancers after treatment of pediatric solid tumors. A comprehensive analysis of germline and tumor samples may be useful to predict the risk of secondary cancers.

Intensification of treatment with vinca alkaloid does not improve outcomes in pediatric patients with Langerhans cell histiocytosis: results from the JPLSG LCH-12 study

Chemotherapy with cytarabine, vincristine (VCR), and prednisolone has achieved low mortality rates in pediatric patients with Langerhans cell histiocytosis (LCH). However, relapse rates remain high, making event-free survival (EFS) rates unsatisfactory. A nationwide clinical trial, LCH-12, tested a modified protocol in which the early maintenance phase was intensified with increasing dosages of VCR. Patients newly diagnosed with multifocal bone (MFB) or multisystem (MS) LCH and aged < 20 years at diagnosis were enrolled between June 2012 and November 2017. Of the 150 eligible patients, 43 with MFB were treated for 30 weeks and 107 with MS LCH were treated for 54 weeks. One patient with MS LCH died of sepsis during the induction phase. The 3-year EFS rates among patients with MFB LCH, risk organ (RO)-negative MS LCH, and RO-positive MS LCH were 66.7% (95% confidential interval [CI], 56.5-77.0%), 66.1% (95% CI 52.9-76.4%), and 51.1% (95% CI 35.8-64.5%), respectively, similar to previously observed rates. EFS rates were significantly lower in patients with disease activity scores > 6 than in those with scores ≤ 6. The strategy that included more intense treatment with VCR was not effective. Other strategies are required to improve outcomes in patients with pediatric LCH.

Natto intake is a risk factor of Bacillus subtilis bacteremia among children undergoing chemotherapy for childhood cancer: A case-control study

BACKGROUND

Natto, a popular, daily food in Japan, is made from soybeans fermented by Bacillus subtilis. The aim of this retrospective case-control study (matched 1: 4) is to determine whether natto intake is a risk factor of B. subtilis bacteremia in this population.

METHODS

The retrospective, matched case-control study was conducted at Tokyo Metropolitan Children's Medical Center between April 2012 and June 2020 and included pediatric patients younger than 15 years who received chemotherapy for cancer. Patients who received hematopoietic stem cell transplantation were excluded. Patients with B. subtilis bacteremia were compared with controls matched for age and underlying diseases. Dietary information within seven days from the date of blood culture collection was extracted from medical records. Multivariate logistic regression was performed to define the risk factors of B. subtilis bacteremia.

RESULTS

In total, 23 patients with B. subtilis bacteremia were identified and matched to 92 controls. The percentage of patients and controls who ingested natto within seven days from the date of blood culture collection was 78% and 50%, respectively. On univariate analysis, the odds ratio of natto intake for B. subtilis bacteremia was 3.6 (95% confidence interval [CI]: 1.2-10.5). Multivariable logistic regression tests after controlling for neutropenia revealed that B. subtilis bacteremia was associated significantly with natto intake at odds ratio 3.3 (95% CI: 1.1-9.6).

CONCLUSION

Natto intake was associated with B. subtilis bacteremia during chemotherapy for childhood cancer.

Development of a population pharmacokinetics and pharmacodynamics model of glucarpidase rescue treatment after high-dose methotrexate therapy

Introduction

Glucarpidase (CPG2) reduces the lethal toxicity of methotrexate (MTX) by rapid degradation.

Methods

In this study, a CPG2 population pharmacokinetics (popPK) analysis in healthy volunteers (phase 1 study) and a popPK-pharmacodynamics (popPK-PD) analysis in patients (phase 2 study, n = 15) who received 50 U/kg of CPG2 rescue for delayed MTX excretion were conducted. In the phase 2 study, the first CPG2 treatment at a dose of 50 U/kg was intravenously administered for 5 min within 12 h after the first confirmation of delayed MTX excretion. The second dose of CPG2, with a plasma MTX concentration >1 μmol/L, was administered to the patient more than 46 h after the start of CPG2 administration.

Results

The population mean PK parameters (95% CI) of MTX, obtained from the final model post hoc, were estimated as follows: CLr_MTX = 2.424 L/h (95% CI: 1.755-3.093), Vc_MTX = 12.6 L (95% CI: 10.8-14.3), Vp_MTX = 2.15 L (95% CI: 1.60-2.70), and α = 8.131 x 10⁵ (4.864 x 10⁵-11.398 x 10⁵). The final model, including covariates, was CLr_MTX (L/h): 3.248 x Body Weight/Serum creatinine/60 (CV 33.5%), Vc_MTX (L): 0.386 x Body Weight/body surface area (CV 29.1%), Vp_MTX (L):3.052 x Body Weight/60 (CV 90.6%), and α (L/h): 6.545 x 10⁵ (CV 79.8%).

Discussion

These results suggest that the pre-CPG2 dose and 24 h after CPG2 dosing were the most important sampling points in the Bayesian estimation of plasma MTX concentration prediction at 48 h. These CPG2-MTX popPK analysis and Bayesian estimation of rebound in plasma MTX concentrations are clinically important to estimate >1.0 μmol/L 48 h after the first CPG2 dosing.

Clinical trial registration

https://dbcentre3.jmacct.med.or.jp/JMACTR/App/JMACTRS06/JMACTRS06.aspx?seqno=2363, identifier JMA-IIA00078 and https://dbcentre3.jmacct.med.or.jp/JMACTR/App/JMACTRS06/JMACTRS06.aspx?seqno=2782, identifier JMA-IIA00097.

Clinical characteristics and treatment of IMP-type carbapenemase-producing Enterobacteriaceae bacteremia: Case series and literature review

BACKGROUND

Several carbapenemases have been identified globally in Enterobacteriaceae. In Japan, IMP-type carbapenemase is the most prevalent, although cases of carbapenemase-producing Enterobacteriaceae (CPE) bacteremia are still scarce. The present case series and literature review aimed to elucidate the clinical characteristics and treatment strategies for IMP-type CPE bacteremia.

METHODS

Clinical data on pediatric cases of IMP-type CPE bacteremia at the Tokyo Metropolitan Children's Medical Center between 2010 and 2020 were collected, and a review of past studies of IMP-type CPE bacteremia has been provided.

RESULTS

Five pediatric episodes of IMP-type CPE bacteremia were identified. Our review of previous literature on IMP-type CPE bacteremia revealed 24 adult patients, but no pediatric patients. All 29 cases had underlying diseases, and 23 (79%) received combination therapy. The median duration of antibiotic therapy was 14 days (interquartile range: 9-14 days). The overall mortality rate was 38% (11/29). The mortality rates associated with monotherapy and combination therapy were 67% (4/6) and 30% (7/23), respectively.

CONCLUSIONS

We report the first case series of IMP-type CPE bacteremia in children. Our review of past studies suggests that combination therapy might lead to better survival outcomes in patients with IMP-type CPE bacteremia. Further research is needed to establish an optimal treatment strategy for IMP-type CPE bacteremia.

Reduced-intensity conditioning is effective for allogeneic hematopoietic stem cell transplantation in infants with MECOM-associated syndrome

Mutations in the MECOM encoding EVI1 are observed in infants who have radioulnar synostosis with amegakaryocytic thrombocytopenia. MECOM-associated syndrome was proposed based on clinical heterogeneity. Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for progressive bone marrow failure. However, data regarding allogeneic HSCT for this rare disease are limited. We retrospectively assessed overall survival, conditioning regimen, regimen-related toxicities and long-term sequelae in six patients treated with allogeneic HSCT. All patients received a reduced-intensity conditioning (RIC) regimen consisting of fludarabine, cyclophosphamide or melphalan, and rabbit anti-thymocyte globulin and/or low-dose total body/thoracic-abdominal/total lymphoid irradiation, followed by allogeneic bone marrow or cord blood transplantation from unrelated donors between 4 and 18 months of age. All patients survived and achieved stable engraftment and complete chimerization with the donor type. Moreover, no patient experienced severe regimen-related toxicities, and only lower grades of acute graft-versus-host disease were observed. Three patients treated with low-dose irradiation had relatively short stature compared to three patients not treated with irradiation. Therefore, allogeneic HSCT with RIC is an effective and feasible treatment for infants with MECOM-associated syndrome. Future studies are needed to evaluate the use of low-dose irradiation to avoid risks of other long-term sequelae.

Discontinuation of tyrosine kinase inhibitors in pediatric chronic myeloid leukemia

BACKGROUND

The feasibility of tyrosine kinase inhibitor (TKI) discontinuation in pediatric chronic myeloid leukemia (CML) remains to be fully elucidated.

PROCEDURES

TKI was prospectively discontinued in patients who were diagnosed with CML at <20 years of age, treated with TKI for ≥3 years, and sustained molecular response 4.0 (MR4.0) for ≥2 years. Molecular relapse was defined as a single loss of major molecular response (MMR) (BCR-ABL1^IS >0.1%). Relapsed patients resumed the same TKI therapy administered before discontinuation.

RESULTS

Twenty-two patients with chronic-phase CML were enrolled, and the median ages at diagnosis and at TKI discontinuation were 9 (range: 1-14) years and 16 (5-26) years, respectively. The median follow-up time after TKI discontinuation was 37 months (range: 24-41 months). The median duration of TKI treatment before discontinuation was 100 (42-178) months, and that of MR4.0 was 53.5 (25-148) months. The treatment-free remission (TFR) rate at 12 months was 50.0% (90% confidence interval: 31.7%-65.8%). Eleven patients experienced loss of MMR within 4 months after TKI discontinuation and resumed TKI as originally prescribed. No progression was observed, and all 11 patients regained MR4.0 after TKI resumption. No patient had a withdrawal syndrome. The quality-of-life analysis suggested that successful TFR may improve academic performance in some patients. In patients who discontinued TKI therapy before puberty, the possibility of improvement in growth velocity upon TKI discontinuation was observed.

CONCLUSIONS

TKI could be discontinued safely in patients with pediatric CML showing a sustained deep MR.

Information needs of children with leukemia and their parents' perspectives of their information needs: a qualitative study

Background

Despite the potential benefits of effective communication, telling a child that they have a life-threatening condition is one of the most daunting challenges. This study aimed to explore the information needs of children with leukemia from the perspectives of children and their parents at the time of diagnosis.

Methods

We conducted an exploratory qualitative study using semi-structured individual interviews with children diagnosed with leukemia between seven and 13 years old (n = 7) and their parents (n = 9). Children and parents’ interview data were analyzed using thematic analysis.

Results

We identified three themes for the information needs of children with leukemia, 1) beginning to cope, 2) avoiding disclosure – protecting child, and 3) informational support. The children and their parents needed to receive understandable information at the best time to cope with cancer. However, the children and parents expressed different views about children’s information needs. The children needed clear information about the disease, treatment, hospitalization, and the benefits of hospitalization from the time of diagnosis. In contrast, the parents felt they should not tell their children about the disease if they were in shock by their child’s cancer diagnosis. Moreover, the parents believed that information that would be incomprehensible to the child and distress should be avoided to protect their children.

Conclusions

While the information needs of children with leukemia are varied, children and their parents need the information to cope with cancer. However, if the parents believe that the information would be distressful, they might manage communication with their children. Healthcare professionals should explore the motivations behind parents’ attitudes against communication with children and confront conflict. Healthcare professionals also should communicate with the children and their parents to understand their information needs and respect children’s views.