High-risk Acute Lymphoblastic Leukemia Research Articles

IKZF1PLUS alterations contribute to outcome disparities in Hispanic/Latino children with B-lymphoblastic leukemia.

Compared to other ethnicities, Hispanics/Latinos (H/L) have a high incidence of acute lymphoblastic leukemia (ALL), enrichment of unfavorable ALL genetic subtypes, and worse outcomes, even after correcting for socioeconomic factors. We previously demonstrated increased incidence of the high-risk genetic drivers IKZF1 deletion and IGH::CRLF2 rearrangement in H/L compared to non-H/L children with B-ALL. Here in an expanded pediatric cohort, we sought to identify novel genetic drivers and secondary genetic alterations in B-ALL associated with H/L ethnicity. Comprehensive clinicopathologic data from patients with B-ALL treated from 2016 to 2020 were analyzed. Subtype was determined from karyotype, fluorescence in situ hybridization (FISH), chromosome microarray (CMA), and our next-generation sequencing (NGS) panel (OncoKids). Non-driver genetic variants were also examined. p-Values less than.05 (Fisher's exact test) were considered significant. Among patients with B-ALL at diagnosis (n=273), H/L patients (189, 69.2%) were older (p=.018), more likely to present with CNS2 or CNS3 disease (p=.004), and NCI high-risk ALL (p=.014) compared to non-H/L patients. Higher incidence of IGH::CRLF2 rearrangement (B-ALL, BCR::ABL1-like, unfavorable; p=.016) and lower incidence of ETV6::RUNX1 rearrangement (favorable, p=.02) were also associated with H/L ethnicity. Among secondary (non-subtype-defining) genetic variants, B-ALL in H/L was associated with IKFZ1 deletion alone (p=.001) or with IGH::CRLF2 rearrangement (p=.003). The IKZF1PLUS profile (IKZF1 deletion plus CDKN2A/2Bdel, PAX5del, or P2RY8::CRLF2 rearrangement without DUX4 rearrangement) was identified as a novel high-risk feature enriched in H/L patients (p=.001). Our study shows enrichment of high-risk genetic variants in H/L B-ALL and raises consideration for novel therapeutic targets.

Donor matters: Donor selection impact on hematopoietic stem cell transplantation outcomes in Hispanic patients with B-cell acute lymphocytic leukemia: Insights from a myeloablative HSCT study

BackgroundHematopoietic stem cell transplantation (HSCT) is a pivotal treatment for high-risk acute lymphocytic leukemia (ALL), although limited by suitable human leukocyte antigen (HLA)-matched sibling donors (MSD). This study evaluates the impact of donor selection on outcomes in post-HSCT Hispanic B-cell ALL patients. MethodologyThis single-center retrospective study evaluates outcomes in 88 adult Hispanic B-cell ALL patients who underwent haploidentical, MSD, or MUD myeloablative HSCT between 2013 and 2023. ResultsCompared to Haploidentical transplants, MSD exhibited worse cumulative incidence of relapse (CIR) (HR = 3.39; P = 0.014) and disease-free survival (DFS) (HR = 2.44; P = 0.048) whereas MUD outcomes did not differ. This effect persisted even when controlling for pre-HSCT stage and Minimal residual disease (MRD) status. In addition, Ph-like was a significant predictor of worse DFS (HR = 3.60; P=0.014) and CIR (HR = 2.97; P=0.035) on multivariate analysis. Older donor age correlated with worse GVHD-free, relapse-free survival (GRFS) in haploidentical transplants (HR = 1.05; P=0.036). ConclusionOur data highlights improved outcomes with younger, haploidentical donors among Hispanic B-cell ALL patients undergoing myeloablative HSCT. This underscores the importance of donor selection in optimizing outcomes for ALL patients.

Combination p53 activation and BCL-xL/BCL-2 inhibition as a therapeutic strategy in high-risk and relapsed acute lymphoblastic leukemia.

Due to the rarity of TP53 mutations in acute lymphoblastic leukemia (ALL), p53 re-activation by antagonism of the p53-MDM2 interaction represents a potential therapeutic strategy for the majority of ALL. Here, we demonstrate the potent antileukemic activity of the MDM2 antagonist idasanutlin in high-risk and relapsed ex vivo coculture models of TP53 wildtype ALL (n = 40). Insufficient clinical responses to monotherapy MDM2 inhibitors in other cancers prompted us to explore optimal drugs for combination therapy. Utilizing high-throughput combination screening of 1971 FDA-approved and clinically advanced compounds, we identified BCL-xL/BCL-2 inhibitor navitoclax as the most promising idasanutlin combination partner. The idasanutlin-navitoclax combination was synergistically lethal to prognostically-poor, primary-derived and primary patient blasts in ex vivo coculture, and reduced leukemia burden in two very high-risk ALL xenograft models at drug concentrations safely attained in patients; in fact, the navitoclax plasma concentrations were equivalent to those attained in contemporary "low-dose" navitoclax clinical trials. We demonstrate a preferential engagement of cell death over G1 cell cycle arrest, mechanistically implicating MCL-1-binding pro-apoptotic sensitizer NOXA. The proposed combination of two clinical-stage compounds independently under clinical evaluation for ALL is of high clinical relevance and warrants consideration for the treatment of patients with high-risk and relapsed ALL.

Abstract 5987: Targeting the spliceosome in high-risk B-cell acute lymphoblastic leukemia

Abstract The outcome for children with high-risk B-cell acute lymphoblastic leukemia (B-ALL) is poor. Disease relapse is speculated to be due to leukemia cells escaping treatment. Our group discovered a unique cell subpopulation in B-ALL that has the capacity to initiate leukemia and is resistant to treatment. Transcriptome studies of this cell population highlight a unique RNA regulation process, specifically RNA splicing. In B-ALL, dysregulated splicing is reported to be associated with drug resistance and disease relapse. SF3B1 is a core component of the spliceosome and an essential protein in the RNA splicing process. SF3B1 inhibition is therapeutic in many cancers. In our current studies, we investigated the therapeutic potential of pladienolide B (Plad-B), an SF3B1 inhibitor, in B-ALL. SF3B1 protein expression was significantly higher in cell lines (Reh and JM1) and 28 primary B-ALL samples (14 each for standard-risk and high-risk), regardless of the risk group, than in normal B-cells (NBs) and hematopoietic stem cells (HSCs). Plad-B showed significant dose-dependent cytotoxicity in the cell lines with IC50 of 1.2nM and 0.6nM, respectively, and three harvested high-risk patient-derived xenograft (PDX) samples with almost the same IC50 as the cell lines. Plad-B did not show cytotoxicity in NBs and HSCs at the same tested concentrations. In vivo efficacy of Plad-B was tested using an Reh xenograft mouse model and a high-risk PDX model. Plad-B, as a single drug treatment, significantly prolonged survival in both models (p<0.01). G2/M cell cycle arrest and apoptosis induction were observed at 24 hours after Plad-B treatment in Reh and JM1. Splicing events were examined by RNA-seq in the treated cells at different time points (15 min, 30 min, and 60 min). Plad B demonstrated rapid splicing inhibition as early as 15 min post-treatment and, at 60 min, splicing was inhibited in 1,669 genes, including apoptosis-associated genes. 2,625 differential splicing events were observed in these genes with ~96% from intron retention and exon skipping. Furthermore, 202 genes showed significant changes in their expression over this time frame. Most of the genes were rapidly downregulated in the treatment group compared to the control, and some were slowly downregulated. There were also some genes which were upregulated, either rapidly or slowly, compared to the control. We demonstrated that Plad-B induced short pro-apoptotic spliced isoforms, instead of anti-apoptotic forms, in BCL2L1 and MCL-1, as early as 60 min after treatment. In conclusion, these data demonstrated the therapeutic potential of SF3B1 inhibition in high-risk B-ALL. Plad-B rapidly inhibited splicing in many genes and downregulated the anti-apoptotic forms of apoptosis-associated genes, leading to cell apoptosis. In future studies, we will identify the downstream targets of Plad-B and further investigate the mechanism of rapid apoptosis induction by SF3B1 inhibition. Citation Format: Yuki Murakami, Hiroaki Konishi, Clifford Tepper, John McPherson, Noriko Satake. Targeting the spliceosome in high-risk B-cell 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 5987.

Abstract 1905: The ROR1 antibody-drug conjugate, MK-2140, enhances the efficacy of established drugs in preclinical models of pediatric acute lymphoblastic leukemia

Abstract Introduction: Children diagnosed with acute lymphoblastic leukemia (ALL) experience ~90% likelihood of cure. However, the outcome for high-risk ALL and children who relapse remains poor. Receptor tyrosine kinase like orphan 1 receptor (ROR1) is a cell surface antigen primarily expressed in embryonic tissue, but also overexpressed in hematological malignancies. UC961 is a humanized IgG monoclonal antibody with high affinity for ROR1. MK-2140 (Zilovertamab vedotin/VLS-101) and VLS-211 are antibody-drug conjugates (ADCs) of UC961 with monomethyl auristatin-E or PNU payloads, respectively. This study evaluated the in vivo efficacy of MK-2140 and VLS211 against pediatric ALL patient derived xenografts (PDXs). Methods: PDXs were selected based on ROR1 mRNA (RNA-seq) and cell surface (flow cytometry) expression and grown as orthotopic disease in immune-deficient NSG mice. Engraftment and drug responses were assessed by flow cytometric enumeration of the proportion of human versus mouse CD45+ cells in peripheral blood (%huCD45+). Events were defined a priori as the %huCD45+ exceeding 25% or leukemia-related morbidity. MK-2140 (2.5 and 5.0 mg/kg) and VLS-211 (0.25 and 0.5 mg/kg) were administered intravenously, weekly x 3 weeks. Vincristine (0.15 mg/kg once weekly), dexamethasone (5 mg/kg daily x 5) and Lasparaginase (1,250 U/kg daily x 5) (VXL) were administered intraperitoneally for 3 weeks, followed by MK-2140 (5 mg/kg weekly x 3 weeks). Drug efficacy was assessed by event-free survival of treated (T) and control (C) groups and by stringent objective response criteria. In receptor occupancy/pharmacokinetic studies, a single dose of MK-2140 was administered and samples collected for analysis at discrete timepoints thereafter. Results: ROR1 mRNA and cell surface expression showed a significant correlation (R=0.83, P=0.021). MK-2140 significantly delayed disease progression in 4/7 PDXs compared to vehicle control (T-C, -2.6 to 20.0 days). At the highest dose, MK-2140 elicited objective responses (remissions) in two PDXs. VLS-211 significantly delayed disease progression in 5/7 PDXs (TC, -1.8 to 70.5 days), including 3 objective responses. Prior treatment with VXL followed by MK-2140 significantly delayed disease progression compared to VXL alone (T-C, 56.8 versus 35.2 days). MK-2140 bound to ROR1+ cells with near 100% occupancy within two hours of treatment, which was sustained for up to 96 h. Consistent with the receptor occupancy data, plasma levels of MK-2140 were maintained at >100 nM for at least 96 h after a single dose (5 mg/kg). Conclusions: MK-2140 and VLS-211 exerted significant single-agent in vivo activity against a panel of pediatric ALL PDXs. MK-2140 significantly enhanced the efficacy of an induction-type regimen and should be considered for further evaluation in a minimal residual disease setting. Citation Format: Richard B. Lock, Kathryn Evans, Ben Watts, Edward P. Bowman, Steven Neuhauser, Timothy Stearns, Jeffrey H. Chuang, Vivek M. Phillip, Katti A. Jessen, Emily L. Jocoy, Carol J. Bult, Beverly A. Teicher, Malcolm A. Smith. The ROR1 antibody-drug conjugate, MK-2140, enhances the efficacy of established drugs in preclinical models of pediatric 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 1905.

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.

Abstract 3271: The casein kinase 2/IKZF1 axis attenuates ceramide accumulation through up-regulation of acid ceramidase: Implications for use of CK2 inhibitors in high-risk pediatric B-cell acute lymphoid leukemia

Abstract Casein Kinase II (CK2), a growth-promoting non-oncogene, is frequently over-expressed in pediatric high-risk B-cell acute lymphoblastic leukemia (B-ALL) leading to proliferation and survival. CK2 phosphorylates the tumor suppressor IKZF1 (IKAROS) resulting in a loss-of DNA-binding activity. Loss of IKZF1 function is associated with poor prognosis in high-risk B-ALL. As such, inhibition of CK2 using silmitasertib (CX-4945), to restore IKZF1 function, is being therapeutically investigated in high-risk B-ALL. CK2 also phosphorylates/activates the mammalian ceramide synthases to increase production of the pro-apoptotic sphingolipid, ceramide (Cer). Therefore, we hypothesized that inhibition of CK2 with CX-4945 would exert both pro-death (restoration of IKAROS function) and pro-survival (decreased Cer production) effects on B-ALL cells. Moreover, this suggests that targeting the sphingolipid metabolic pathway in tandem with CX-4945 could be a novel strategy for treatment of high-risk B-ALL. To this end, we examined the effects of CX-4945 on sphingolipid levels and the enzymes of the sphingolipid metabolic pathway. Unexpectedly, we determined that CX-4945 dose-dependently increased expression of ceramide synthase 1 (CERS1) and acid ceramidase (AC) proteins, in an IKZF1 dependent manner. Increased CERS1 expression/production of C18:0 Cer has been linked to enhanced mitophagy (i.e., lysosomal clearance of damaged mitochondria) in head and neck squamous cell carcinoma. Induction of mitophagy by CX-4945 was confirmed by western blot analysis of mitofusin-1 and Drp-1 levels. Up-regulation of AC, a lysosomal protein, metabolizes C18:0 Cer to sphingosine for recycling and prevents Cer-induced lysosomal membrane permeabilization. Thus, induction of mitophagy and metabolic breakdown of Cer could potentially reduce the apoptotic efficacy of CX-4945 in B-ALL cell lines. We, therefore, tested whether inhibition of AC would synergize with CX-4945 to enhance B-ALL cell death. Indeed, synergy was observed with the AC inhibitor, SACLAC, in multiple cell lines. Consistent with the observation of synergy between CX-4945 and SACLAC, the combination also enhanced cleavage of PARP indicating an enhancement of cell death. We are currently testing the efficacy of a combination of CX-4945 and AC inhibitors in cell-line derived xenograft models of human B-ALL. Together, these findings indicate that simultaneous targeting of CK2 and AC represents a rationally selected combinatorial therapeutic strategy that overcomes the ability of cancer cells to adapt to single agent targeted therapies by altering pro- and/or anti-apoptotic pathways. Citation Format: Jeremy A. Hengst, Diwakar Bastihalli Tukaramrao, Todd Fox, Arati Sharma, Dhimant Desai, Sinisa Dovat. The casein kinase 2/IKZF1 axis attenuates ceramide accumulation through up-regulation of acid ceramidase: Implications for use of CK2 inhibitors in high-risk pediatric B-cell acute lymphoid 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 3271.

Effect of apolipoprotein E (APOE) gene polymorphisms on the lipid profile of children being treated for acute lymphoblastic leukemia.

Medications used to treat acute lymphoblastic leukemia (ALL), such as L-asparaginase, can cause blood lipid disturbances. These can also be associated with polymorphisms of the lipoprotein lipase (LpL) and apolipoprotein E (APOE) genes. We aimed to investigate the association between lipid profile, certain LpL and APOE gene polymorphisms (rs268, rs328, rs1801177 and rs7412, rs429358 respectively) as well as the risk subgroup in 30 pediatric patients being treated for ALL, compared with 30 pediatric ALL survivors and 30 healthy controls. The only APOE gene polymorphism with significant allelic and genotypic heterogeneity was rs429358. Further analysis of this polymorphism showed that genotype (CC, CT, or TT) was significantly associated with (1) changes in the lipid profile at the end of consolidation (total cholesterol, LDL, apo-B100, and lipoprotein a) and during re-induction (total cholesterol and apo-B100), and (2) classification in the high risk-ALL subgroup (for CC genotype/C allele presence). Lipid abnormalities in children being treated for ALL may be associated with the APOE genotype, which is also possibly associated with risk stratification. Further research is needed to confirm the potential prognostic value of these findings.

Abstract P30: Therapeutic activation of pre-B-cell receptor signaling in high-risk pediatric ALL: exploiting TCF3 and MYC-linked vulnerabilities

Abstract P30: Therapeutic activation of pre-B-cell receptor signaling in high-risk pediatric ALL: exploiting TCF3 and MYC-linked vulnerabilities

Peg-asparaginase associated toxicities in children with acute lymphoblastic leukemia: A single-center cross-sectional study

BackgroundLeukemia is the most prevalent type of cancer affecting children, representing approximately 35% of cancer diagnoses in Saudi Arabia. Notably, significant improvement in the overall survival and cure rates for pediatrics with acute lymphoblastic leukemia (ALL) has been attributed to adding asparaginase to the chemotherapy regimen. However, the administration of these agents may lead to a multifactorial range of toxicities that often alter treatment outcomes. ObjectiveThe study aimed to characterize the prevalence of common toxicities related to polyethylene glycol (PEG) asparaginase in children aged 0–14 years diagnosed with ALL. Additionally, it assessed the types of toxicities associated with intravenous (IV) and intramuscular (IM) administration of Peg-asparaginase. MethodIt was an observational retrospective cross-sectional study. Data was extracted from the hospital's electronic health record (EPIC). Using EPIC, we reviewed medical charts of all pediatric patients below 14 years old diagnosed with ALL who received at least one dose of PEG-asparaginase between January 2020 and March 2023. The toxicity grading was based on the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE). ResultsOne hundred and ninety-one patients with ALL were included in the study. Overall, 79 toxicity episodes were experienced by the study patients. Anaphylaxis/hypersensitivity (36.7%) and hepatotoxicity (31.6%) were the most prevalent toxicities reported, followed by pancreatitis and hyperglycemia (12.7% each). According to the CTCAE grading, approximately 70% of toxicities were categorized as Grade 3 and 4. Notably, 60% of the events occurred during the induction and consolidation phase of therapy. Interestingly, there was no significant difference in rates of toxicities between patients receiving IV or IM PEG-asparaginase. ConclusionThe distribution of toxicities highlighted in our study aligns with findings from previously published studies. Furthermore, multivariate analysis indicated that patients with high-risk ALL and T-ALL were more likely to develop toxicities compared to other forms of ALL.

Biological Markers of High-Risk Childhood Acute Lymphoblastic Leukemia.

Childhood acute lymphoblastic leukemia (ALL) has witnessed substantial improvements in prognosis; however, a subset of patients classified as high-risk continues to face higher rates of relapse and increased mortality. While the National Cancer Institute (NCI) criteria have traditionally guided risk stratification based on initial clinical information, recent advances highlight the pivotal role of biological markers in shaping the prognosis of childhood ALL. This review delves into the emerging understanding of high-risk childhood ALL, focusing on molecular, cytogenetic, and immunophenotypic markers. These markers not only contribute to unraveling the underlying mechanisms of the disease, but also shed light on specific clinical patterns that dictate prognosis. The paradigm shift in treatment strategies, exemplified by the success of tyrosine kinase inhibitors in Philadelphia chromosome-positive leukemia, underscores the importance of recognizing and targeting precise risk factors. Through a comprehensive exploration of high-risk childhood ALL characteristics, this review aims to enhance our comprehension of the disease, offering insights into its molecular landscape and clinical intricacies in the hope of contributing to future targeted and tailored therapies.

461 - Management of wound dehiscence during active chemotherapy in a young adult with high risk ALL

461 - Management of wound dehiscence during active chemotherapy in a young adult with high risk ALL

Efficacy and safety in early application of Ruxolitinib for high-risk acute lymphoblastic leukemia to prevent GVHD and recurrence after allogeneic hematopoietic stem cell transplantation

BackgroundAllogeneic hematopoietic stem cell transplantation (allo-HSCT) has been identified as the potentially curative treatment for high-risk acute lymphoblastic leukemia (ALL) in adult patients. However, relapse of the disease and/or development of graft-versus-host disease (GVHD) remain to be the most common barriers for successful allo-HSCT. Preclinical studies showed that ruxolitinib, a Janus tyrosine kinase (Jak)1 and Jak2 inhibitor, has a selective anti-GVHD effects while preserving a potent graft-versus-leukemia (GVL) effect. Our study aimed to investigate the efficacy and safety in early application of ruxolitinib for the high-risk ALL patients to prevent GVHD. MethodsThere were eight patients undergoing allo-HSCT at the Bone Marrow Transplantation Center of the Third Xiangya Hospital of Central South University between April 2020 and April 2021. Ruxolitinib (5–10 mg twice daily) was administered early (median time: 45 days) after stem cell infusion. ResultsAfter a median follow-up of 14 months (range from 8 to 18 months), the ALL disease relapse occurred in two cases. Among all eight patients, two of them developed grade I/II acute (a) GVHD, while no patient developed grade III/IV aGVHD, and one patient developed chronic (c) GVHD. As for the virus activation, no patient developed EBV activation or EBV related lymphoproliferative disease, and three patients developed CMV activation. Our results suggest that the early application of ruxolitinib could safely and effectively prevent the occurrence of GVHD after allo-HSCT for the high-risk ALL patients. However, it may have a limited effect on preventing the recurrence of high-risk ALL and thus may require additional therapy with other anti-relapse drugs. ConclusionsOur preliminary observations suggest that an early application of ruxolitinib can safely and effectively prevent the occurrence of GVHD after allo-HSCT for the high-risk ALL patients. However, ruxolitinib may have a limited effect on preventing the ALL recurrence of high-risk patients.

Fungal Otomastoiditis caused by Aspergillus fumigatus in an immunocompromised patient: case report and literature review

This case report describes a 10-year-old male diagnosed with high-risk B-cell Acute Lymphoblastic Leukemia at a tertiary care center undergoing consolidation with the Total XV protocol. The patient, with a history of Rhino-sinusal Aspergillosis and secondary prophylaxis, presented with recurrent middle ear infections, bilateral non-purulent serous discharge, otalgia, mastoid pain, persistent high-grade fever, and profound neutropenia. Fungal ostomastoiditis was diagnosed and treated with targeted antifungals, yielding a positive response.

Invasive Fungal Infections in Children with Acute Leukemia: Epidemiology, Risk Factors, and Outcome.

Invasive fungal infections (IFI) cause morbidity and mortality in children with acute leukemia (AL). We retrospectively collected data on febrile neutropenic episodes (FNE) in AL children (2016-2021) and assessed factors associated with proven/probable IFI. Ninety-three children developed 339 FNE. Seventeen (18.3%) children developed 19 proven/probable IFI (11 yeast; eight molds). The proven/probable yeast IFI rate was 6/52 (11.5%) in children who belong to the high risk for IFI category (HR-IFI-AL: high-risk acute lymphocytic leukemia (ALL), acute myeloid leukemia, relapse); and 5/41 (12.2%) in the non-HR-IFI-AL category (standard/intermediate risk ALL). The proven/probable mold IFI rate was 7/52 (13.5%) in HR-IFI-AL children and 1/41 (2.4%) in the non-HR-IFI-AL category. In the multivariable analysis, underlying genetic syndrome, oral mucositis, and older age were significantly associated with proven/probable IFI, while a longer time since AL diagnosis was protective. Two of 13 (15.4%) HR-IFI-AL children died because of IFI. The elevated risks of proven/probable mold IFI and the associated mortality in HR-IFI-AL children, and high risk of invasive candidiasis in the non-HR-IFI-AL group, emphasize the need for the close monitoring of local epidemiology and the adjustment of practices accordingly.

Comparison of high-throughput single-cell RNA-seq methods for ex vivo drug screening.

Functional precision medicine (FPM) aims to optimize patient-specific drug selection based on the unique characteristics of their cancer cells. Recent advancements in high throughput ex vivo drug profiling have accelerated interest in FPM. Here, we present a proof-of-concept study for an integrated experimental system that incorporates ex vivo treatment response with a single-cell gene expression output enabling barcoding of several drug conditions in one single-cell sequencing experiment. We demonstrate this through a proof-of-concept investigation focusing on the glucocorticoid-resistant acute lymphoblastic leukemia (ALL) E/R+Reh cell line. Three different single-cell transcriptome sequencing (scRNA-seq) approaches were evaluated, each exhibiting high cell recovery and accurate tagging of distinct drug conditions. Notably, our comprehensive analysis revealed variations in library complexity, sensitivity (gene detection), and differential gene expression detection across the methods. Despite these differences, we identified a substantial transcriptional response to fludarabine, a highly relevant drug for treating high-risk ALL, which was consistently recapitulated by all three methods. These findings highlight the potential of our integrated approach for studying drug responses at the single-cell level and emphasize the importance of method selection in scRNA-seq studies. Finally, our data encompassing 27327 cells are freely available to extend to future scRNA-seq methodological comparisons.

Risk factors and clinical impact of thrombosis during induction chemotherapy for pediatric acute lymphoblastic leukemia: A report from CYP-C.

Thromboembolism (TE) is associated with reduced survival in pediatric acute lymphoblastic leukemia (ALL). It has been hypothesized that TE might signal leukemic aggressiveness. The objective was to determine risk factors for TE during ALL induction (TEind ) therapy and whether TEind is associated with treatment refractoriness. This retrospective cohort study using the population-based Cancer in Young People Canada (CYP-C) registry included children <15 years of age diagnosed with ALL (2000-2019) and treated at one of 12 Canadian pediatric centers outside of Ontario. Univariate and multivariable logistic regression models were used to determine risk factors for TEind and whether TEind predicted induction failure and ALL treatment intensification. The impact of TEind on overall and event-free survival was estimated using Cox proportional hazard regression models. The study included 2589 children, of which 45 (1.7%) developed a TEind . Age (<1 year and ≥10 years vs. 1-<10 years), T-cell phenotype, high-risk ALL, and central nervous system involvement were all associated with TEind in univariate analysis. Age and T-cell phenotype remained independent predictors of TEind in multivariable analysis. Induction failure occurred in 53 patients (2.1%). TEind was not associated with induction failure (OR: not estimable) or treatment intensification (adjusted OR [95% CI]: 0.66 [0.26-1.69]). TEind was independently associated with overall survival (adjusted HR [95% CI]: 2.54 [1.20-5.03]) but not event-free survival (adjusted HR [95% CI] 1.86 [0.98-3.51]). In this population-based study of children treated with contemporary chemotherapy protocols, TEind was associated with age and T-cell phenotype and mortality but did not predict induction failure.

Intensified conditioning regimens with total marrow irradiation/etoposide/cyclophosphamide and busulfan/etoposide/cyclophosphamide overcome the impact of pre-transplant minimal residual disease on outcomes in high-risk acute lymphoblastic leukemia patients in complete remission.

Among high-risk acute lymphoblastic leukemia (ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), those with positive minimal residual disease (MRD) are susceptible to poor outcomes. Therefore, it is necessary to determine the most suitable preparatory regimen for these patients. Data were analyzed from 141 patients who received allo-HSCT and were diagnosed with high-risk ALL. These patients underwent intensified conditioning regimens, including either total marrow and lymphoid irradiation (TMLI)-etoposide (VP16)-cyclophosphamide (CY) or busulfan (BU)-VP16-CY between October 2016 and November 2022. A total of 141 individuals were in complete remission (CR) before transplantation and, among all patients, 90 individuals exhibited a negative MRD status and 51 patients had a positive MRD status. In patients who tested negative for MRD, the incidence of relapse within a 2-year timeframe was 25.0% (24.8%-25.5%), compared with 32.2% (31.2%-33.2%) in MRD-positive patients; however, this difference was not statistically significant. There were no significant differences in the 2-year disease-free survival (DFS) and 2-year overall survival (OS) rates between the MRD-negative and MRD-positive groups (DFS: 67.2% (57.9%-78.1%) vs. 55.5% (42.6%-72.3%); OS: 69.0% (61.9%-88.2%) vs. 66.7% (53.9%-82.5%)). Furthermore, no notable variations were observed in the occurrence of transplant-related mortality (TRM) and graft-versus-host disease (GVHD) across the two groups. This study reveals the benefits of TMLI-VP16-CY and BU-VP16-CY conditioning regimens in high-risk ALL patients with CR and MRD-positive status. A large-scale prospective clinical trial is warranted in the future.

ALCL Protocol of the DOIG Research Institute 2003: results of treatment of anaplastic large cell lymphoma in children in a comparative multicenter clinical trial

Introduction. Anaplastic large cell lymphoma (ALCL) is characterized by clinical, morphological and immunohistochemical heterogeneity. Both intensive block regimens and programs similar to those used in the treatment of acute lymphoblastic leukemia (ALL) are used in therapy. Taking into account the prognostically unfavorable effect of the expression of T-cell markers by tumor cells, a protocol ALCL NII DOIG 2003 was developed, which takes into account not only risk groups, but also immunophenotypic features of the tumor substrate.Aim. To evaluate the treatment effectiveness of children with ALCL according to the protocol ALCL NII DOIG 2003 in comparison with the standard protocol NHL-BFM 95.Materials and methods. The study included 100 patients with newly diagnosed ALCL who received treatment from 2000 to 2023 in 5 federal and regional pediatric oncohematology departments. The patients were divided into 2 groups depending on the protocol of therapy: I group — 48 patients treated with protocol ALCL NII DOIG 2003; II group — 52 patients treated according to the NHL-BFM 95 protocol. The basis of the protocol ALCL NII DOIG 2003 was made up of high-intensity block regimes similar to those used in the treatment of high-risk T-precursor ALL. A comparative assessment of the overall, event-free and relapse-free survival of patients was carried out depending on the therapeutic protocol using the SPSS 21.0 program. Results. The 10-year overall survival rate in patients from I group was 95.3 ± 3.3 %, II group — 82.0 ± 5.4 % (p = 0.037). 10- year event-free survival in I group was 95.3 ± 3.3 %, II — 68.6 ± 6.5 % (p = 0.001). 10-year relapse-free survival in I group of patients was 97.3 ± 2.7 %, while in the II group — 74.4 ± 6.4 % (p = 0.003).Conclusion. The obtained results indicate the high effi ciency of a differentiated, immuno-oriented approach to the treatment of ALCL with the ALCL NII DOIG 2003 protocol, making it possible to achieve signifi cantly higher survival rates of patients compared to the standard treatment protocol.

Outcomes of allogeneic stem cell transplantation in acute leukemias – single centre study

Aim: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is recommended in first complete remission (CR) for adverse and intermediate-risk acute myeloid leukemia (AML) and not recommended for AML patients with favourable disease. Allo-HSCT is standard of care in high-risk acute lymphoblastic leukaemia (ALL) and relapsed ALL but is not indicated for standard-risk ALL. Even though in many studies benefit for survival was proven for these patients, relapse rates (RR) at one year (32.9% for LAM and 34% for LAL) remains problematic. We want to report the outcomes of patients treated for acute leukaemia in our centre. Materials and methods: We conducted a retrospective descriptive analysis of 215 patients with acute leukaemia treated with allo-HSCT between 2017 and 2022 in Fundeni Clinical Institute. Data analysis aimed the overall survival (OS) rate, progression free survival (PFS) and RR at one year based on genetic risk, number of CR, minimal residual disease (MRD) status and conditioning regimen used. Results: At one year evaluation we observed OS rate of 64% and a 34% RR for ALL patients, while AML patients had a 74% OS rate and 13% RR. Conclusions: The results obtained in our centre are similar to the ones reported in literature. The highest risk of relapse and smallest rate of survival are registered for patients who present with negative risk factors. The multifactorial influence over OS and RR impose the need for future studies in which different patient categories can benefit from an optimal therapeutic management.