Pediatric T-cell Research Articles

Prognostic significance of early nk cell recovery in pediatric t-cell replete allogeneic hematopoietic stem cell transplantation.

Early immune reconstitution, particularly of natural killer (NK) cells with strong graft-versus-leukemia effects, is crucial for the prognosis of patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). This retrospective study examined 122 pediatric patients with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML) who underwent T-cell replete allo-HSCT at the Children's Hospital of Soochow University from 2019 to 2021. Peripheral blood lymphocyte counts on days 30 and 60 post-transplant were analyzed, focusing on NK cell recovery and its impact on overall survival (OS), relapse-free survival (RFS), non-relapse mortality (NRM), relapse, graft-versus-host disease, and CMV reactivation. Patients were categorized into high and low NK cell groups by the median NK cell counts at day 30 (NK30) and day 60 (NK60) after HSCT. Patients with high NK30 and NK60 levels had significantly better 3-year OS rates compared to their respective low NK count groups (86.8% ± 4.7% versus 67.6% ± 7.0%, P = 0.046; 95.7% ± 3.0% versus 63.7% ± 8.7%, P < 0.001, respectively). NK60 was found to be an independent predictor for 3-year OS and RFS in multivariate analysis. Early NK reconstitution was also related to lower NRM rates. However, this correlation disappeared in patients with ALL and those undergoing haploidentical transplantation. In addition, A positive association between early T cell and NK cell reconstitution was found in our study. Higher NK cell counts on days 60 can predict superior OS, RFS and lower NRM in pediatric AML allo-HSCT patients.

Pediatric Cutaneous T-Cell Neoplasms: Clinical and Pathological Features, Updated Classifications, and CriticalDifferential Diagnoses.

Cutaneous T-cell lymphoid neoplasms in childhood are exceedingly rare, presenting with a wide spectrum of clinical presentation and outcomes. Due to numerous clinical and pathological mimics, an integrated evaluation of clinical, histopathological, immunohistochemical, and molecular findings is critical for a diagnosis. Here, we review the clinical and pathological features, updated classifications, and critical differential diagnoses of cutaneous T-cell lymphoid neoplasms in children.

Cost-utility of nelarabine for the first-line treatment of newly diagnosed pediatric T-cell acute lymphoblastic leukemia in Canada.

The Children's Oncology Group (COG)-AALL0434 trial investigated the addition of nelarabine to the augmented Berlin-Frankfurt-Münster (aBFM) protocol in patients (1.0-30.99years) with newly diagnosed T-cell acute lymphoblastic leukemia (T-ALL). Despite demonstrating superior outcomes, nelarabine is not currently funded by many health systems, in part due to a lack of cost-effectiveness data. We estimated the cost-utility of nelarabine for this indication from a Canadian public healthcare payer perspective. We developed a microsimulation model that followed hypothetical patients with newly diagnosed T-ALL from post-induction therapy to death. Three health states were modeled: relapse-free, post-relapse, and death. Efficacy was estimated using AALL0434 and retrospective data from Ontario, Canada. Costs were obtained from Canadian sources. Utility estimates and long-term mortality risks were sourced from literature. Total healthcare costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) were reported. Probabilistic and scenario analyses were conducted. Incorporating nelarabine in the aBFM protocol increased costs by $51,670 Canadian dollars per patient, but resulted in 1.97 more QALYs and an ICER of $26,184/QALY. Most of the identified cost and benefit were accrued within the AALL0434 trial period (first 11years post diagnosis) and while patients were in the relapse-free health state. Across multiple scenarios, the ICER was stable under an assumed $50,000/QALY threshold. Incorporating nelarabine into aBFM was cost-effective across different scenarios and assumptions. These results support its funding by public and private payers.

Enhancer looping protein LDB1 modulates MYB expression in T-ALL cell lines in vitro by cooperating with master transcription factors

BackgroundDespite significant progress in the prognosis of pediatric T-cell acute lymphoblastic leukemia (T-ALL) in recent decades, a notable portion of children still confronts challenges such as treatment resistance and recurrence, leading to limited options and a poor prognosis. LIM domain-binding protein 1 (LDB1) has been confirmed to exert a crucial role in various physiological and pathological processes. In our research, we aim to elucidate the underlying function and mechanisms of LDB1 within the background of T-ALL.MethodsEmploying short hairpin RNA (shRNA) techniques, we delineated the functional impact of LDB1 in T-ALL cell lines. Through the application of RNA-Seq, CUT&Tag, and immunoprecipitation assays, we scrutinized master transcription factors cooperating with LDB1 and identified downstream targets under LDB1 regulation.ResultsLDB1 emerges as a critical transcription factor co-activator in cell lines derived from T-ALL. It primarily collaborates with master transcription factors (ERG, ETV6, IRF1) to cooperatively regulate the transcription of downstream target genes. Both in vitro and in vivo experiments affirm the essential fuction of LDB1 in the proliferation and survival of cell lines derived from T-ALL, with MYB identified as a significant downstream target of LDB1.ConclusionsTo sum up, our research establishes the pivotal fuction of LDB1 in the tumorigenesis and progression of T-ALL cell lines. Mechanistic insights reveal that LDB1 cooperates with ERG, ETV6, and IRF1 to modulate the expression of downstream effector genes. Furthermore, LDB1 controls MYB through remote enhancer modulation, providing valuable mechanistic insights into its involvement in the progression of T-ALL.

Association of CD34 Expression with Future Relapse in Pediatric T-cell Acute Lymphoblastic Leukemia

Background: Developing novel prognostic markers is crucial for childhood T-cell acute lymphoblastic leukemia (T-ALL). Objectives: This study aimed to investigate whether the prognostic impact of CD34, a progenitor marker, is associated with outcomes. Methods: This retrospective cohort study included 82 risk-adapted pediatric patients with T-ALL who were treated under the National Protocol of Childhood ALL in China (NPCLC)-ALL2008 from March 2008 to December 2016. Results: CD34 expression was observed in 37.8% of all T-ALL patients, with a median expression level of 62.7%. Patients with CD34 expression had a favorable event-free survival (EFS, 74.2% [66.3% - 82.1%]) with a hazard ratio of 0.69 (P = 0.33) and a reduced cumulative incidence of relapse (CIR, 22.6% [15.0% - 30.2%]; P = 0.86) at five years. Even after adjusting for potential factors and competing events in multivariable regression models, there was no connection between the CD34 immunophenotype and the risk of recurrence. Conclusions: CD34 expression did not serve as a predictive factor for relapse in this limited series. Larger multicenter studies are recommended to determine whether this biomarker at initial diagnosis can predict outcomes.

QRICH1 suppresses pediatric T-cell acute lymphoblastic leukemia by inhibiting GRP78

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy that commonly affects children and adolescents with a poor prognosis. The terminal unfolded protein response (UPR) is an emerging anti-cancer approach, although its role in pediatric T-ALL remains unclear. In our pediatric T-ALL cohort from different centers, a lower QRICH1 expression was found associated with a worse prognosis of pediatric T-ALL. Overexpression of QRICH1 significantly inhibited cell proliferation and stimulated apoptosis of T-ALL both in vitro and in vivo. Upregulation of QRICH1 significantly downregulated 78 KDa glucose-regulated protein (GRP78) and upregulated CHOP, thus activating the terminal UPR. Co-overexpression of GRP78 in T-ALL cells overexpressing QRICH1 partially reverted the inhibited proliferation and stimulated apoptosis. QRICH1 bound to the residues Asp212 and Glu155 of the nucleotide-binding domain (NBD) of GRP78, thereby inhibiting its ATP hydrolysis activity. In addition, QRICH1 was associated with endoplasmic reticulum (ER) stress in T-ALL, and overexpression of QRICH1 reversed drug resistance. Overall, low QRICH1 expression is an independent risk factor for a poor prognosis of pediatric T-ALL. By inhibiting GRP78, QRICH1 suppresses pediatric T-ALL.

Clinical and pathological features of pediatric peripheral T-cell lymphoma after solid organ transplantation

Clinical and pathological features of pediatric peripheral T-cell lymphoma after solid organ transplantation

Pediatric T-cell lymphoblastic lymphomas but not leukemias harbor TRB::NOTCH1 fusions with unfavorable outcome

AbstractT-cell lymphoblastic lymphoma (T-LBL) and T-cell acute lymphoblastic leukemia (T-ALL) have common and distinguishing clinical and molecular features. Molecular prognostic factors are needed for T-LBL. We assessed the prevalence and prognostic impact of the T-cell receptor β (TRB)::NOTCH1 fusion in 192 pediatric patients with T-LBL and 167 pediatric patients with T-ALL, using novel multiplex polymerase chain reaction and genomic capture high-throughput sequencing techniques. The fusion was detected in 12 patients with T-LBL (6.3%) but in none of the patients with T-ALL (P = .0006, Fisher exact test). In T-LBL, the TRB::NOTCH1 fusion was associated with a significantly higher incidence of relapse (67% vs 17% in gene fusion-negative patients, P < .001, Fisher exact test). The breakpoint in TRB was most frequently located in J2-7 (n = 6). In NOTCH1, the breakpoints varied between exon 24 and 27. Consequently, a truncated NOTCH1 with its dimerization, regulation, and signal transduction domains gets controlled by strong TRB enhancer elements. This study reveals a novel recurrent genetic variant with significant prognostic relevance in T-LBL, which was absent in T-ALL. The TRB::NOTCH1 fusion in T-LBL suggests a possible unique pathogenic mechanism divergent from T-ALL. Further studies will validate the role of the TRB::NOTCH1 fusion as prognostic marker in T-LBL and elucidate its pathogenic mechanisms.

NOTCH1 fusions in pediatric T-cell lymphoblastic lymphoma: Ahigh-risk subgroup with CCL17 (TARC) levels as diagnostic biomarker.

Twenty percent of children with T-cell lymphoblastic lymphoma (T-LBL) will relapse and have an extremely poor outcome. Currently, we can identify a genetically low-risk subgroup in pediatric T-LBL, yet these high-risk patients who need intensified or alternative treatment options remain undetected. Therefore, there is an urgent need to recognize these high-risk T-LBL patients through identification of molecular characteristics and biomarkers. By using RNA sequencing which was performed in 29/49 T-LBL patients who were diagnosed in the Princess Maxima Center for Pediatric Oncology between 2018 and 2023, we discovered a previously unknown high-risk biological subgroup of children with T-LBL. This subgroup is characterized by NOTCH1 gene fusions, found in 21% of our T-LBL cohort (6/29). All patients presented with a large mediastinal mass, pleural/pericardial effusions, and absence of blasts in the bone marrow, blood, and central nervous system. Blood CCL17 (C-C Motif Chemokine Ligand 17, TARC) levels were measured at diagnosis in 26/29 patients, and all six patients with NOTCH1 gene fusions patients exclusively expressed highly elevated blood CCL17 levels, defining a novel and previously not known clinically relevant biomarker for T-cell lymphoblastic lymphoma. Four out of these six patients relapsed during therapy, a fifth developed a therapy-related acute myeloid leukemia during maintenance therapy. These data indicate that T-LBL patients with a NOTCH1 fusion have a high risk of relapse which can be easily identified using a blood CCL17 screening at diagnosis. Further molecular characterization through NOTCH1 gene fusion analysis offers these patients the opportunity for treatment intensification or new treatment strategies.

NGS-based stratification refines the risk stratification in T-ALL and identifies a very-high-risk subgroup of patients

AbstractWe previously reported a better outcome in adult and pediatric T-cell acute lymphoblastic leukemia (T-ALL) harboring NOTCH1 and/or FBXW7 mutations without alterations of K-N-RAS and PTEN genes. Availability of high-throughput next-generation sequencing (NGS) strategies led us to refine the outcome prediction in T-ALL. Targeted whole-exome sequencing of 72 T-ALL–related oncogenes was performed in 198 adults with T-ALLs in first remission from the GRAALL-2003/2005 protocols and 242 pediatric patients with T-ALLs from the FRALLE2000T. This approach enabled the identification of, to our knowledge, the first NGS-based classifier in T-ALL, categorizing low-risk patients as those with N/F, PHF6, or EP300 mutations, excluding N-K-RAS, PI3K pathway (PTEN, PIK3CA, and PIK3R1), TP53, DNMT3A, IDH1/2, and IKZF1 alterations, with a 5-year cumulative incidence of relapse (CIR) estimated at 21%. Conversely, the remaining patients were classified as high risk, exhibiting a 5-year CIR estimated at 47%. We externally validated this stratification in the pediatric cohort. NGS-based classifier was highly prognostic independently of minimal residual disease (MRD) and white blood cell (WBC) counts, in both adult and pediatric cohorts. Integration of the NGS-based classifier into a comprehensive risk-stratification model, including WBC count at diagnosis and MRD at the end of induction, enabled the identification of an adverse-risk subgroup (25%) with a 5-year CIR estimated at 51%, and a favorable-risk group (32%) with a 5-year CIR estimated at 12%. NGS-based stratification combined with WBC and MRD sharpens the prognostic classification in T-ALL and identifies a new subgroup of patients who may benefit from innovative therapeutic approaches. The GRAALL-2003/2005 studies were registered at www.ClinicalTrials.gov as #NCT00222027 and #NCT00327678.

Cytogenomic characterization of pediatric T-cell acute lymphoblastic leukemia reveals TCR rearrangements as predictive factors for exceptional prognosis

BackgroundT-cell acute lymphoblastic leukemia (T-ALL) represents a rare and clinically and genetically heterogeneous disease that constitutes 10–15% of newly diagnosed pediatric ALL cases. Despite improved outcomes of these children, the survival rate after relapse is extremely poor. Moreover, the survivors must also endure the acute and long-term effects of intensive therapy. Although recent studies have identified a number of recurrent genomic aberrations in pediatric T-ALL, none of the changes is known to have prognostic significance. The aim of our study was to analyze the cytogenomic changes and their various combinations in bone marrow cells of children with T-ALL and to correlate our findings with the clinical features of the subjects and their treatment responses.ResultsWe performed a retrospective and prospective comprehensive cytogenomic analysis of consecutive cohort of 66 children (46 boys and 20 girls) with T-ALL treated according to BFM-based protocols and centrally investigated cytogenetics and immunophenotypes. Using combinations of cytogenomic methods (conventional cytogenetics, FISH, mFISH/mBAND, arrayCGH/SNP and MLPA), we identified chromosomal aberrations in vast majority of patients (91%). The most frequent findings involved the deletion of CDKN2A/CDKN2B genes (71%), T-cell receptor (TCR) loci translocations (27%), and TLX3 gene rearrangements (23%). All chromosomal changes occurred in various combinations and were rarely found as a single abnormality. Children with aberrations of TCR loci had a significantly better event free (p = 0.0034) and overall survival (p = 0.0074), all these patients are living in the first complete remission. None of the abnormalities was an independent predictor of an increased risk of relapse.ConclusionsWe identified a subgroup of patients with TCR aberrations (both TRA/TRD and TRB), who had an excellent prognosis in our cohort with 5-year EFS and OS of 100%, regardless of the presence of other abnormality or the translocation partner. Our data suggest that escalation of treatment intensity, which may be considered in subsets of T-ALL is not needed for nonHR (non-high risk) patients with TCR aberrations.

Identifying Candidate Gene Drivers Associated with Relapse in Pediatric T-Cell Acute Lymphoblastic Leukemia Using a Gene Co-Expression Network Approach.

Pediatric T-cell Acute Lymphoblastic Leukemia (T-ALL) relapses are still associated with a dismal outcome, justifying the search for new therapeutic targets and relapse biomarkers. Using single-cell RNA sequencing (scRNAseq) data from three paired samples of pediatric T-ALL at diagnosis and relapse, we first conducted a high-dimensional weighted gene co-expression network analysis (hdWGCNA). This analysis highlighted several gene co-expression networks (GCNs) and identified relapse-associated hub genes, which are considered potential driver genes. Shared relapse-expressed genes were found to be related to antigen presentation (HLA, B2M), cytoskeleton remodeling (TUBB, TUBA1B), translation (ribosomal proteins, EIF1, EEF1B2), immune responses (MIF, EMP3), stress responses (UBC, HSP90AB1/AA1), metabolism (FTH1, NME1/2, ARCL4C), and transcriptional remodeling (NF-κB family genes, FOS-JUN, KLF2, or KLF6). We then utilized sparse partial least squares discriminant analysis to select from a pool of 481 unique leukemic hub genes, which are the genes most discriminant between diagnosis and relapse states (comprising 44, 35, and 31 genes, respectively, for each patient). Applying a Cox regression method to these patient-specific genes, along with transcriptomic and clinical data from the TARGET-ALL AALL0434 cohort, we generated three model gene signatures that efficiently identified relapsed patients within the cohort. Overall, our approach identified new potential relapse-associated genes and proposed three model gene signatures associated with lower survival rates for high-score patients.

Abstract 5117: CK2 inhibiton exhibits synergistic effect in acute lymphoblastic leukemia

Abstract Survival for pre-B cell Acute lymphoblastic leukemia (B ALL) has improved greatly, however. High risk (HR) subgroups continue to result in significant mortality and morbidity of pediatric oncology patients. Pediatric T-cell acute lymphoblastic leukemia (T-ALL) is a lethal disease, often associated with high-risk clinical features. T-ALL therapy has made less improvement than B ALL and continues to represent a significant number of high-risk outcomes. Novel treatment strategies are required to overcome chemotherapy resistance and improve morbidity for HR B ALL. The development of treatments that can overcome chemotherapy resistance is essential for improving survival in T-ALL. Deletions of IKZF1, resulting in decreased IKAROS function, are present in High-risk ALL patients. Casein kinase 2 (CK2), a protein kinase upregulated in ALL, phosphorylates IKAROS preventing DNA binding reducing transcriptional regulation in ALL patients. Past studies have shown that pharmacologic inhibition of CK2 with CX-4945 rescues IKAROS function as a transcriptional regulator. Receptor tyrosine kinase c-KIT is transcriptionally regulated by IKAROS and is often upregulated in cancer. The purpose of this study was to determine whether restoration of IKAROS via CX-4945 would act in a synergistic manner with c-KIT inhibitor imatinib in ALL.Methods/results B-ALL Nalm6 cells were treated with imatinib over 72-hours to establish the half-maximal inhibitory concentration (IC50). The IC50 was used to determine the concentration range of imatinib to be used in combination with CX-4945 in a 72-hour synergy analysis of cytotoxicity.. Cell viability was measured using WST-1 cell proliferation assay. The data were analyzed using Calcusyn and synergy was defined as a combination index below 0.85. The study was repeated to determine a more precise range of synergy. The cytotoxicity of single drug c-KIT inhibitor, Imatinib, in Nalm6 B-ALL yielded an IC50 of 25uM while CK2 inhibitor CX-4945 resulted in 4uM. When a combination was administered with a constant dose of CX-4945 at 4uM and varying concentrations of imatinib, synergy was observed at multiple dose combinations. Conclusion: The data shows that CK2 inhibitor, CX-4945, and c-KIT inhibitor, imatinib, exhibit a synergistic therapeutic effect. Imatinib is indicated for use in Philadelphia positive (Ph+) acute lymphoblastic leukemia so future studies will include testing CX-4945/imatinib synergy in Ph+ BALL where we expect to see more potent synergistic effect. Citation Format: Daniel Gary Bogush, Joseph Schramm, Katarina Dovat, Yali Ding, Chingakham Singh, Sinisa Dovat. CK2 inhibiton exhibits synergistic effect in acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5117.

Williams-Beuren syndrome in pediatric T-cell acute lymphoblastic leukemia: A rare case report and review of literature.

Williams-Beuren syndrome (WBS) is a rare genetic disorder caused by hemizygous microdeletion of contiguous genes on chromosome 7q11.23. Although the phenotype features extensive heterogeneity in severity and performance, WBS is not considered to be a predisposing factor for cancer development. Currently, hematologic cancers, mainly Burkitt lymphoma, are rarely reported in patients with WBS. Here in, we report a unique case of T-cell acute lymphoblastic leukemia in a male child with WBS. This retrospective study analyzed the clinical data of this case receiving chemotherapy were analyzed. This is a retrospective study. The patient, who exhibited a typical WBS phenotype and presented with hemorrhagic spots. Chromosomal genome-wide chip analysis (CMA) revealed abnormalities on chromosomes 7 and 9. The fusion gene STIL-TAL1 and mutations in BCL11B, NOTCH1, and USP7 have also been found and all been associated with the occurrence of T-cell leukemia. The patient responded well to the chemotherapy. To the best of our knowledge, this is the first reported case of WBS in T-cell acute lymphoblastic leukemia. We want to emphasize that the occurrence of leukemia in this patient might be related to the loss of 7q11.23 and microdeletion of 9p21.3 (including 3 TSGs), but the relationship between WBS and malignancy remains unclear. Further studies are required to clarify the relationship between WBS and malignancy.

In vivo activity of the second-generation proteasome inhibitor ixazomib against pediatric T-cell acute lymphoblastic leukemia xenografts

The overall survival rate of patients with T-cell acute lymphoblastic leukemia (T-ALL) is now 90%, although patients with relapsed T-ALL face poor prognosis. The ubiquitin-proteasome system maintains normal protein homeostasis, and aberrations in this pathway are associated with T-ALL. Here we demonstrate the in vitro and in vivo activity of ixazomib, a second-generation orally available, reversible, and selective proteasome inhibitor against pediatric T-ALL cell lines and patient-derived xenografts (PDXs) grown orthotopically in immunodeficient NOD.Cg-PrkdcscidIL2rgtm1Wjl/SzJAusb (NSG) mice. Ixazomib was highly potent in vitro, with half-maximal inhibitory concentration (IC50) values in the low nanomolar range. As a monotherapy, ixazomib significantly extended mouse event-free survival of five out of eight T-ALL PDXs in vivo.

Nelarabine-containing salvage therapy and conditioning regimen in transplants for pediatric T-cell acute lymphoblastic leukemia and lymphoma.

Therapy for relapsed or refractory (r/r) T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) in children is challenging, and new treatment methods are needed. We retrospectively analyzed eight patients with r/r T-ALL (five patients) and T-LBL (three patients) who were treated with nelarabine (NEL) plus etoposide, cyclophosphamide, and intrathecal therapy, administered 3days apart. Five patients achieved a complete response, and the other three achieved a partial response (PR). All patients underwent hematopoietic stem cell transplantation (HSCT) after two cycles of treatment, except for one patient who received one cycle. Three patients who had previously received HSCT were treated with reduced-intensity conditioning regimens, including fludarabine, melphalan, and NEL; one survived for over 5years after the second HSCT. Grade 2 neuropathy occurred in one patient, but other severe toxicities commonly associated with NEL were not observed during NEL administration in combination with chemotherapy. The 2-year overall survival and event-free survival rates were 60.0% and 36.5%, respectively. The addition of NEL to reinduction chemotherapy was useful in achieving remission and did not lead to excessive toxicity. In addition, a conditioning regimen, including NEL, appeared to be effective in patients who had previously undergone HSCT.

Pediatric cutaneous T-cell neoplasm and mimics with gamma-delta expression: Not always aggressive.

Pediatric cutaneous T-cell lymphoma with γδ immunophenotype is extremely rare. Only a few cases of γδ T-cell neoplasm have been reported in the literature, and therefore little is known whether γδ T-cell neoplasms in children are distinct from their adult counterparts with respect to the clinicopathological presentation, behavior, and prognosis. In this study, we demonstrate three unique pediatric cutaneous T-cell neoplasm and mimics with increased γδ T cells. All cases showed an indolent clinical course.

Efficacy and Safety Analysis of Prophylactic Brentuximab Vedotin Administration after Pediatric Acute Leukemia Haploidentical Hematopoietic Stem Cell Transplantation

Objective: Acute graft-versus-host disease (aGVHD) is a common complication following allogeneic hematopoietic stem cell transplantation. Currently, the reported incidence of moderate to severe aGVHD in domestic cases is 13%-47%, while the incidence of grade III/IV aGVHD after haploidentical transplantation ranges from 7.9% to 13.8%. Severe aGVHD is one of the leading causes of early post-transplant mortality. This study aims to analyze whether the administration of Brentuximab vedotin after transplantation can reduce the incidence of aGVHD without increasing disease relapse rates and viral infections. Methods: A retrospective analysis was conducted on 50 pediatric leukemia patients who underwent haploidentical hematopoietic stem cell transplantation (HSCT) at our hospital between June 2017 and July 2022. These patients received prophylactic treatment with Brentuximab vedotin (20mg) on day +1 and day +4 post-transplantation to prevent aGVHD. The median age of the patients was 4.1 years (range: 0.6-16.0 years), with a gender ratio of 25:25 (male:female). At the time of diagnosis, the median white blood cell (WBC) count was 19.9×10 9/L (range: 2.0-863×10 9/L) for 41 patients, while the WBC count at initial diagnosis was unknown for 9 patients. Among the cases, 22 were acute lymphoblastic leukemia (ALL), and 28 were acute myeloid leukemia (AML). Before transplantation, 28 patients were in CR1, 14 in CR2, 2 in CR3, and 6 in NR. All patients received myeloablative conditioning regimens, with 33 receiving Bu/Cy, 15 receiving TBI/Cy, 1 receiving Bu/Flu, and 1 receiving TBI/Flu. The median follow-up time was 29.1 months (range: 3.1-70.1 months). Detailed patient data are presented in Table 1. Results: All 50 patients achieved 100% engraftment of white blood cells, with a median time of 15 days (range: +10 to +21 days). Platelet engraftment occurred in a median time of 9 days (range: +5 to +78 days), except for one patient who did not achieve platelet engraftment. This particular patient was diagnosed with AML and experienced hematologic relapse and extramedullary relapse before transplantation. The patient died due to disease relapse 90 days after transplantation.The incidence of aGVHD after transplantation was 44%, with 28% experiencing grade I-II and 16% experiencing grade III-IV aGVHD. The incidence of CMV viremia was 40%, with a median time to diagnosis of 36 days (range: +19 to +84 days), while the incidence of EBV viremia was 8%, with a median time to diagnosis of 47 days (range: +14 to +87 days). During the follow-up period, five patients experienced disease relapse, with a median time to relapse of 92 days after transplantation (range: +67 to +181 days). Among the relapsed patients, 2 had ALL (both in CR2), and 3 had acute myeloid leukemia (all in NR). Seven patients died during the follow-up, including 4 with AML and 3 with ALL. The causes of death were disease relapse in 3 cases, infection in 2 cases, TMA in 1 case, and cGVHD in 1 case. The estimated 5-year overall survival (OS) and leukemia-free survival (LFS) rates were 86%, and the 5-year cumulative relapse rate was 10% (see Figures 1, 2, and 3). In comparison, a control group of 44 pediatric acute T-cell lymphoblastic leukemia patients who underwent haploidentical transplantation without prophylactic Brentuximab vedotin treatment between January 5, 2021, and June 30, 2022, were analyzed. In the control group, the incidence of aGVHD was 56.8% (P=0.007), with 36.4% experiencing grade I-II and 20.4% experiencing grade III-IV aGVHD. The incidence of CMV viremia was 68.2% (P=0.006), and the incidence of EBV viremia was 29.5% (P=0.007). The relapse rate was 15.9%, and the mortality rate was 27.3%. Conclusion: For pediatric acute leukemia haploidentical HSCT, the administration of Brentuximab vedotin (20mg) on days +1 and +4 after transplantation, in addition to conventional aGVHD prophylaxis (CsA+MMF+sMTX), significantly reduced the overall incidence of aGVHD and grade I-II aGVHD. Administering Brentuximab vedotin on days +1 and +4 did not increase the rates of CMV or EBV infection nor did it increase the risk of disease relapse.

Global Distribution of Clinical Trials on Chimeric Antigen Receptor T-Cells in the Pediatric Population: The Economic Impact on Clinical Trials Development

Keywords: Chimeric Antigen Receptor T cell, Pharmacoeconomic, Pediatric, Clinical Trials With the success of Chimeric Antigen Receptor (CAR) T-cell therapy in the pediatric population, new clinical trials have surged worldwide. To date, no previous study has analyzed the effect of socioeconomic factors on the development of clinical trials for CAR T-cells in the pediatric population. In recent years new countries and emerging economies have contributed significantly to the development of CAR T-cell clinical trials. A better understanding of the socioeconomic factors that influenced these trends will facilitate the future development of this cellular therapy field. To assess the impact of socioeconomic factors related to the development of clinical trials on CAR T-cell therapies in the pediatric population, we analyzed data entries from clinical trials registered to the Clinicaltrials.gov database. To query the information, we used the following keywords “(leukemia OR cancer OR lymphoma OR malignancies OR tumor OR solid tumor) AND (CAR OR chimeric antigen receptor OR CAR T-cell OR adoptive immunotherapy OR immune effector OR cellular therapy) AND (Child)”. In addition, we used different filters that allowed the selection of studies that focused on patients 18 years of age and younger. Data corresponding to entries with a data cut-off of July-2023 were included. In addition, we use the World Bank country's macroeconomic database (January 1 st, 2009 to December 31 st, 2022). We found 4,297 results in the Clinicaltrials.gov platform; we excluded 3,978 clinical trials that did not involve the pediatric population (≤18 years) or CAR T-cell intervention. There were 319 clinical trials included, sponsored in 19 countries, as shown in Figure A. Of those studies, 207 (64.9%) were conducted in China, 74 (23.2%) in the U.S., and 21 (6.5%) in Europe. Not surprisingly, the number of clinical trials is strictly proportional to each country's Gross Domestic Product (GDP) and Research and Development (R&amp;D) expenditure, as shown in Figure B. Pearsons' coefficient between GDP and the number of trials registered per country is 0.8 (p-value &amp;lt; 0.001); similarly, Pearsons's coefficient between R&amp;D expenditure and the number of problems reported per country is 0.64 (p-value &amp;lt; 0.004). The United States and China are developing 88% of the Clinical trials, and 96% of the clinical trials occur in countries ranked in the top 10 highest GDP. Our database analysis shows a notable disparity in the countries leading cutting-edge research in CAR T-cell therapy for pediatric oncology. The primary locations for these clinical studies are countries ranked in the top 10 in terms of GDP, with China and the USA being the main contributors. Access to clinical trials plays a crucial role in improving cancer patients' outcomes, and this disparity in the development of cellular therapies is likely to impact children from middle and low-GDP countries significantly. Urgent strategies are required to address this issue and ensure more equitable access to advanced technologies and clinical trials in cellular therapy for pediatric cancers. These strategies should become a high priority for national and international health departments and organizations in the coming years. By promoting more comprehensive clinical trial access and collaboration, we can work towards reducing these disparities and providing better treatment options for all children facing pediatric cancer.

Chimeric Antigen Receptor T Cell Therapies Clinical Trials in Pediatric Oncology: A Retrospective Analysis from Clinicaltrials.Gov

Background: Chimeric Antigen Receptor (CAR) T-cell clinical trials are growing exponentially. Database analysis can help identify scientific trends and generate projections regarding potential approvals before the results of the studies are completed or published. This is particularly interesting in pediatric oncology, where available analyses from repository databases are scarce or not available. Because of that reason, we sought to analyze the clinical trial public records from entries related to CAR T-cell clinical studies in pediatric patients (18 years or younger) uploaded to the clinicaltrials.gov database. Methods: We query the available data from clinicaltrials.gov using the following keywords: “CAR T cell in pediatrics”, “CAR T cell and cancer”, “chimeric antigen receptor”, “CAR T AND tumor antigen”, 'CAR T cell antigens“, ”Tumor antigens targeted by CAR T cells“, ”engineered T cells“, ”modified T cell“, ”CAR T cells in Cancer“, ”CAR T cell therapy“, ”CAR T cell therapy AND Cancer“ (data cut off July-2023). The data were tabulated, and the trials that did not meet the search criteria were excluded manually. Data cleansing was performed using published scientific data, web search-based information, and patent databases. Results: We found 4297 results in the Clinicaltrials.gov platform; we excluded 3978 clinical trials that did not involve the pediatric population (&amp;lt;18 years) or CAR T-cell intervention. The final analysis included 319 clinical trials posted on the clinicaltrials.gov website by the cut-off date. 207 (64.9%) were conducted in China, 74 (23.2%) in the US, and 21 (6.5%) in Europe. Most CAR T-cell trials focused on hematological cancer (89%), followed by non-CNS solid tumors 8%, and CNS tumors 3%. The most frequent targets were CD19 (46%), CD7 (7%), followed by GD2, CD22, CD123, CD19 + CD22 and CD30. Most clinical trials did not report the construct generation used in their CAR T cell product (58%). Among the trials with that information, second-generation constructs (2G) were used in 32% of the studies, followed by 3G and 4G constructs (5% of studies each). Most clinical trials were in early stages of development, Phase 1 or 2 (75%). We observed a continuous increase in the number of clinical trials registered yearly, except for a small reduction in 2022 and 2021, probably related to COVID restrictions and challenges. Overall, the general trend predicts at least a 50% yearly increase in registered studies ( Figure 1). Similarly, to what is observed in adult clinical trials, the most common signaling domains are 2G CAR constructs expressing either CD28 or 4-1BB as costimulatory domains. Among those, 4-1BB being is the most popular choice. Conclusion: Our findings indicate a growing interest in the clinical development of CAR T-cell therapies applied to pediatric oncology. Most of these studies are in early phase I and II and focus primarily on hematological cancers using second-generation constructs targeting CD19. The is a steady increase in the number of studies registered each year that predicts future FDA approvals using CAR T-cell products.