Alternative donor transplantation for severe aplastic anemia: a comparative study of the SAAWP EBMT.

ABSTRACT: Selecting the most suitable alternative donor becomes challenging in severe aplastic anemia (SAA) when a matched sibling donor (MSD) is unavailable. We compared outcomes in patients with SAA undergoing stem cell transplantation (SCT) from matched unrelated donors (MUD) (n = 1106), mismatched unrelated donors (MMUD) (n = 340), and haploidentical donors (Haplo) (n = 206) registered in the European Society for Blood and Marrow Transplantation database (2012-2021). For Haplo SCT, only those receiving posttransplant cyclophosphamide for graft-versus-host disease (GVHD) prophylaxis were included. Median age was 20 years, and the median time from diagnosis to transplantation 8.7 months. Compared with MUD, MMUD (hazard ratio [HR], 2.93; 95% confidence interval [CI], 1.52-5.6) and Haplo (HR, 5.15; 95% CI, 2.5-10.58) showed significantly higher risks of primary graft failure. MUD had lower rates of acute GVHD compared with MMUD and Haplo (grade 2-4: 13%, 22%, and 19%, respectively; P < .001; grade 3-4: 5%, 9%, and 7%, respectively; P = .028). The 3-year nonrelapse mortality rate was 14% for MUD, 19% for MMUD, and 27% for Haplo (P < .001), whereas overall survival and GVHD and relapse-free survival (GRFS) rates were 81% and 73% for MUD, 74% and 65% for MMUD, and 63% and 54% for Haplo, respectively (P < .001). In addition to donor type, multivariable analysis identified other factors associated with GRFS such as patient age, performance status, and interval between diagnosis and transplantation. For patients with SAA lacking an MSD, our findings support MUDs as the preferable alternative donor option. However, selecting between an MMUD and Haplo donor remains uncertain and requires further exploration.

CTP synthase 1 deficiency in humans reveals its central role in lymphocyte proliferation.

Lymphocyte functions triggered by antigen recognition and co-stimulation signals are associated with a rapid and intense cell division, and hence with metabolism adaptation. The nucleotide cytidine 5' triphosphate (CTP) is a precursor required for the metabolism of DNA, RNA and phospholipids. CTP originates from two sources: a salvage pathway and a de novo synthesis pathway that depends on two enzymes, the CTP synthases (or synthetases) 1 and 2 (CTPS1 with CTPS2); the respective roles of these two enzymes are not known. CTP synthase activity is a potentially important step for DNA synthesis in lymphocytes. Here we report the identification of a loss-of-function homozygous mutation (rs145092287) in CTPS1 in humans that causes a novel and life-threatening immunodeficiency, characterized by an impaired capacity of activated T and B cells to proliferate in response to antigen receptor-mediated activation. In contrast, proximal and distal T-cell receptor (TCR) signalling events and responses were only weakly affected by the absence of CTPS1. Activated CTPS1-deficient cells had decreased levels of CTP. Normal T-cell proliferation was restored in CTPS1-deficient cells by expressing wild-type CTPS1 or by addition of exogenous CTP or its nucleoside precursor, cytidine. CTPS1 expression was found to be low in resting T cells, but rapidly upregulated following TCR activation. These results highlight a key and specific role of CTPS1 in the immune system by its capacity to sustain the proliferation of activated lymphocytes during the immune response. CTPS1 may therefore represent a therapeutic target of immunosuppressive drugs that could specifically dampen lymphocyte activation.

Successful Management of Hepatosplenic Infection Due to Saccharomyces cerevisiae in a Child With Acute Lymphoblastic Leukemia.

Saccharomyces cerevisiae is an emerging pathogen within the immunocompromised. We present a 4-year-old boy with acute lymphoblastic leukemia presenting with polymerase chain reaction-confirmed hepatosplenic S. cerevisiae infection and significant immune reconstitution symptoms. We explore the challenges of monitoring treatment efficacy using C-Reactive protein, ß-D-glucan, and imaging and the administration of chemotherapy alongside antifungals and steroids for control of immune reconstitution syndrome.

Multicenter phase 1/2 application of adenovirus-specific T cells in high-risk pediatric patients after allogeneic stem cell transplantation.

BACKGROUND: Adenovirus (ADV) reactivation can cause significant morbidity and mortality in children after allogeneic stem cell transplantation. Antiviral drugs can control viremia, but viral clearance requires recovery of cell-mediated immunity. METHOD: This study was an open-label phase 1/2 study to investigate the feasibility of generating donor-derived ADV-specific T cells (Cytovir ADV, Cell Medica) and to assess the safety of pre-emptive administration of ADV-specific T cells in high-risk pediatric patients after allogeneic hematopoietic stem cell transplantation (HSCT) to treat adenoviremia. Primary safety endpoints included graft-versus-host disease (GvHD), and secondary endpoints determined antiviral responses and use of antiviral drugs. RESULTS: Between January 2013 and May 2016, 92 donors were enrolled for the production of ADV T cells at three centers in the United Kingdom (UK), and 83 products were generated from 72 mobilized peripheral blood harvests and 20 steady-state whole blood donations. Eight children received Cytovir ADV T cells after standard therapy and all resolved ADV viremia between 15 and 127 days later. ADV-specific T cells were detectable using enzyme-linked immunospot assay (ELISpot) in the peripheral blood of all patients analyzed. Serious adverse events included Grade II GvHD, Astrovirus encephalitis and pancreatitis. CONCLUSION: The study demonstrates the safety and feasibility of pre-emptively manufacturing peptide pulsed ADV-specific cells for high-risk pediatric patients after transplantation and provides early evidence of clinical efficacy.

Long-term outcome of Hurler syndrome patients after hematopoietic cell transplantation: an international multicenter study.

Mucopolysaccharidosis type I-Hurler syndrome (MPS-IH) is a lysosomal storage disease characterized by multisystem morbidity and death in early childhood. Although hematopoietic cell transplantation (HCT) has been performed in these patients for more than 30 years, large studies on the long-term outcome of patients with MPS-IH after HCT are lacking. The goal of this international study was to identify predictors of the long-term outcome of patients with MPS-IH after successful HCT. Two hundred seventeen patients with MPS-IH successfully engrafted with a median follow-up age of 9.2 years were included in this retrospective analysis. Primary endpoints were neurodevelopmental outcomes and growth. Secondary endpoints included neurologic, orthopedic, cardiac, respiratory, ophthalmologic, audiologic, and endocrinologic outcomes. Considerable residual disease burden was observed in the majority of the transplanted patients with MPS-IH, with high variability between patients. Preservation of cognitive function at HCT and a younger age at transplantation were major predictors for superior cognitive development posttransplant. A normal α-l-iduronidase enzyme level obtained post-HCT was another highly significant predictor for superior long-term outcome in most organ systems. The long-term prognosis of patients with MPS-IH receiving HCT can be improved by reducing the age at HCT through earlier diagnosis, as well as using exclusively noncarrier donors and achieving complete donor chimerism.

Haematopoietic stem cell transplantation in inborn errors of metabolism.

PURPOSE OF REVIEW: This review summarizes the main results of haematopoietic stem cell transplantation (HSCT) in selected inborn errors of metabolism (IEMs). RECENT FINDINGS: Early diagnosis and immediate referral to an IEM specialist is of paramount importance to improve clinical outcome: patients who are transplanted early or in their presymptomatic phase generally achieve better correction of their somatic symptoms and neurocognitive development. Long-term outcome in children with Hurler syndrome is influenced by age at HSCT, baseline clinical status and post-HSCT enzyme levels. Myeloablative Busulfan-based conditioning regimens with therapeutic drug monitoring are recommended to achieve full donor engraftment and more robust enzyme delivery after HSCT. Gene therapy can lead to production of supranormal enzyme levels, and preliminary clinical results are also promising in IEMs historically not responsive to allogeneic HSCT. SUMMARY: Allogeneic HSCT has largely contributed to the improved survival and quality of life of many children affected by IEMs. Neonatal screening could enable earlier HSCT, and this might significantly reduce residual disease burden and improve clinical outcome. Novel strategies, such as gene therapy, have shown encouraging clinical results in selected IEMs and might become more widely available in the future, with potentially better enzyme delivery and reduced transplant-related toxicity.

BCSH/BSBMT/UK clinical virology network guideline: diagnosis and management of common respiratory viral infections in patients undergoing treatment for haematological malignancies or stem cell transplantation.

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology, the British Society for Bone Marrow Transplantation and the UK Clinical Virology Network has reviewed the available literature and made recommendations for the diagnosis and management of respiratory viral infections in patients with haematological malignancies or those undergoing haematopoietic stem cell transplantation. This guideline includes recommendations for the diagnosis, prevention and treatment of respiratory viral infections in adults and children. The suggestions and recommendations are primarily intended for physicians practising in the United Kingdom.

Enzyme replacement therapy prior to haematopoietic stem cell transplantation in Mucopolysaccharidosis Type I: 10 year combined experience of 2 centres.

Haematopoietic stem cell transplantation is the treatment of choice for the severe form of Mucopolysaccharidosis Type I, or Hurler syndrome. In many centres standard practice is to deliver enzyme replacement therapy alongside haematopoietic stem cell transplantation to improve the condition of the patient prior to transplant. We report the combined 10 year experience of this approach in two paediatric metabolic and transplant centres. Of 81 patients who underwent a first transplant procedure for Hurler, 88% (71/81) survived and 81% (66/81) were alive and engrafted at a median follow-up of 46 months (range 3-124 months). The incidence of grade II-IV acute and any chronic graft versus host disease was 17% and 11% respectively. Urinary glycosaminoglycans were significantly reduced after a period of enzyme replacement therapy, and further reductions were seen at 13-24 months and 25+months after transplantation. In several individuals with decreased cardiac contractility, an improvement of their condition during enzyme replacement therapy enabled them to undergo transplantation, with one individual receiving full intensity conditioning.

Mutations in TRNT1 cause congenital sideroblastic anemia with immunodeficiency, fevers, and developmental delay (SIFD).

Mutations in genes encoding proteins that are involved in mitochondrial heme synthesis, iron-sulfur cluster biogenesis, and mitochondrial protein synthesis have previously been implicated in the pathogenesis of the congenital sideroblastic anemias (CSAs). We recently described a syndromic form of CSA associated with B-cell immunodeficiency, periodic fevers, and developmental delay (SIFD). Here we demonstrate that SIFD is caused by biallelic mutations in TRNT1, the gene encoding the CCA-adding enzyme essential for maturation of both nuclear and mitochondrial transfer RNAs. Using budding yeast lacking the TRNT1 homolog, CCA1, we confirm that the patient-associated TRNT1 mutations result in partial loss of function of TRNT1 and lead to metabolic defects in both the mitochondria and cytosol, which can account for the phenotypic pleiotropy.

Heparan sulfate inhibits hematopoietic stem and progenitor cell migration and engraftment in mucopolysaccharidosis I.

Mucopolysaccharidosis I Hurler (MPSI-H) is a pediatric lysosomal storage disease caused by genetic deficiencies in IDUA, coding for α-l-iduronidase. Idua(-/-) mice share similar clinical pathology with patients, including the accumulation of the undegraded glycosaminoglycans (GAGs) heparan sulfate (HS), and dermatan sulfate (DS), progressive neurodegeneration, and dysostosis multiplex. Hematopoietic stem cell transplantation (HSCT) is the most effective treatment for Hurler patients, but reduced intensity conditioning is a risk factor in transplantation, suggesting an underlying defect in hematopoietic cell engraftment. HS is a co-receptor in the CXCL12/CXCR4 axis of hematopoietic stem and progenitor cell (HSPC) migration to the bone marrow (BM), but the effect of HS alterations on HSPC migration, or the functional role of HS in MPSI-H are unknown. We demonstrate defective WT HSPC engraftment and migration in Idua(-/-) recipient BM, particularly under reduced intensity conditioning. Both intra- but especially extracellular Idua(-/-) BM HS was significantly increased and abnormally sulfated. Soluble heparinase-sensitive GAGs from Idua(-/-) BM and specifically 2-O-sulfated HS, elevated in Idua(-/-) BM, both inhibited CXCL12-mediated WT HSPC transwell migration, while DS had no effect. Thus we have shown that excess overly sulfated extracellular HS binds, and sequesters CXCL12, limiting hematopoietic migration and providing a potential mechanism for the limited scope of HSCT in Hurler disease.

Hematopoietic cell transplantation for mucopolysaccharidosis patients is safe and effective: results after implementation of international guidelines.

Allogeneic hematopoietic cell transplantation (HCT) is the only treatment able to prevent progressive neurodegenerative disease in a selected group of mucopolysaccharidosis (MPS) disorders. However, its use was historically limited by the high risk of graft failure and transplantation-related morbidity and mortality. Therefore, since 2005 new international HCT guidelines for MPS disorders were proposed. The survival and graft outcomes of MPS patients receiving HCT according to these guidelines in 2 European centers of expertise were evaluated. Two consecutive conditioning regimens were used, busulfan/cyclophosphamide or fludarabine/busulfan-based, both with exposure-targeted i.v. busulfan. A noncarrier matched sibling donor (MSD), matched unrelated cord blood (UCB), or matched unrelated donor (MUD) were considered to be preferred donors. If not available, a mismatched UCB donor was used. Participants were 62 MPS patients (56 MPS type I-Hurler, 2 MPS type II, 2 MPS type III, and 2 MPS type VI) receiving HCT at median age 13.5 months (range, 3 to 44). Forty-one patients received a UCB donor, 17 MSD, and 4 MUD. High overall survival (95.2%) and event-free survival (90.3%) were achieved with only low toxicity: 13.3% acute graft-versus-host disease aGVHD) grades II to IV and 14.8% chronic GVHD (1.9% extensive). A mismatched donor predicted for lower event-free survival (P = .04). A higher age at HCT was a predictor for both aGVHD (P = .001) and chronic GVHD (P = .01). The use of a mismatched donor was a predictor for aGVHD (P = .01). Higher rates of full-donor chimerism were achieved in successfully transplanted UCB recipients compared with MSD/MUD (P = .002). If complying with the international HCT guidelines, HCT in MPS patients results in high safety and efficacy. This allows extension of HCT to more attenuated MPS types. Because a younger age at HCT is associated with reduction of HCT-related toxicity, newborn screening may further increase safety.

A novel syndrome of congenital sideroblastic anemia, B-cell immunodeficiency, periodic fevers, and developmental delay (SIFD).

Congenital sideroblastic anemias (CSAs) are a heterogeneous group of inherited disorders identified by pathological erythroid precursors with perinuclear mitochondrial iron deposition in bone marrow. An international collaborative group of physicians and laboratory scientists collated clinical information on cases of CSA lacking known causative mutations, identifying a clinical subgroup of CSA associated with B immunodeficiency, periodic fevers, and development delay. Twelve cases from 10 families were identified. Median age at presentation was 2 months. Anemia at diagnosis was sideroblastic, typically severe (median hemoglobin, 7.1 g/dL) and markedly microcytic (median mean corpuscular volume, 62.0 fL). Clinical course involved recurrent febrile illness and gastrointestinal disturbance, lacking an infective cause. Investigation revealed B-cell lymphopenia (CD19⁺ range, 0.016-0.22 × 109/L) and panhypogammaglobulinemia in most cases. Children displayed developmental delay alongside variable neurodegeneration, seizures, cerebellar abnormalities, sensorineural deafness, and other multisystem features. Most required regular blood transfusion, iron chelation, and intravenous immunoglobulin replacement. Median survival was 48 months, with 7 deaths caused by cardiac or multiorgan failure. One child underwent bone marrow transplantation aged 9 months, with apparent cure of the hematologic and immunologic manifestations. We describe and define a novel CSA and B-cell immunodeficiency syndrome with additional features resembling a mitochondrial cytopathy. The molecular etiology is under investigation.

Transplantation in inborn errors of metabolism: current considerations and future perspectives.

Inborn errors of metabolism (IEM) comprise an assorted group of inherited diseases, some of which are due to disordered lysosomal or peroxisomal function and some of which might be improved following haemopoietic cell transplantation (HCT). In these disorders, the onset in infancy or early childhood is typically accompanied by rapid deterioration, resulting in early death in the more severe phenotypes. Timely diagnosis and immediate referral to an IEM specialist are essential steps in optimal management. Treatment recommendations are based on the diagnosis, its phenotype, rate of progression, prior extent of disease, family values and expectations and the risks and benefits associated with available therapies, including HCT. International collaborative efforts are of utmost importance in determining outcomes of therapy for these rare diseases, and have improved those outcomes significantly over recent decades. This discussion focuses on HCT in IEM, providing an international perspective on progress, limitations, and future directions.

Impact of immune modulation with in vivo T-cell depletion and myleoablative total body irradiation conditioning on outcomes after unrelated donor transplantation for childhood acute lymphoblastic leukemia.

To determine whether in vivo T-cell depletion, which lowers GVHD, abrogates the antileukemic benefits of myeloablative total body irradiation-based conditioning and unrelated donor transplantation, in the present study, we analyzed 715 children with acute lymphoblastic leukemia. Patients were grouped for analysis according to whether conditioning included antithymocyte globulin (ATG; n = 191) or alemtuzumab (n = 132) and no in vivo T-cell depletion (n = 392). The median follow-up time was 3.5 years for the ATG group and 5 years for the alemtuzumab and T cell-replete groups. Using Cox regression analysis, we compared transplantation outcomes between groups. Compared with no T-cell depletion, grade 2-4 acute and chronic GVHD rates were significantly lower after in vivo T-cell depletion with ATG (relative risk [RR] = 0.66; P = .005 and RR = 0.55; P < .0001, respectively) or alemtuzumab (RR = 0.09; P < .003 and RR = 0.21; P < .0001, respectively). Despite lower GVHD rates after in vivo T-cell depletion, nonrelapse mortality, relapse, overall survival, and leukemia-free survival (LFS) did not differ significantly among the treatment groups. The 3-year probabilities of LFS after ATG-containing, alemtuzumab-containing, and T cell-replete transplantations were 43%, 49%, and 46%, respectively. These data suggest that in vivo T-cell depletion lowers GVHD without compromising LFS among children with acute lymphoblastic leukemia who are undergoing unrelated donor transplantation with myeloablative total body irradiation-based regimens.

Myeloid/Microglial driven autologous hematopoietic stem cell gene therapy corrects a neuronopathic lysosomal disease.

Mucopolysaccharidosis type IIIA (MPSIIIA) is a lysosomal storage disorder caused by mutations in N-sulfoglucosamine sulfohydrolase (SGSH), resulting in heparan sulfate (HS) accumulation and progressive neurodegeneration. There are no treatments. We previously demonstrated improved neuropathology in MPSIIIA mice using lentiviral vectors (LVs) overexpressing SGSH in wild-type (WT) hematopoietic stem cell (HSC) transplants (HSCTs), achieved via donor monocyte/microglial engraftment in the brain. However, neurological disease was not corrected using LVs in autologous MPSIIIA HSCTs. To improve brain expression via monocyte/microglial specificity, LVs expressing enhanced green fluorescent protein (eGFP) under ubiquitous phosphoglycerate kinase (PGK) or myeloid-specific promoters were compared in transplanted HSCs. LV-CD11b-GFP gave significantly higher monocyte/B-cell eGFP expression than LV-PGK-GFP or LV-CD18-GFP after 6 months. Subsequently, autologous MPSIIIA HSCs were transduced with either LV-PGK-coSGSH or LV-CD11b-coSGSH vectors expressing codon-optimized SGSH and transplanted into MPSIIIA mice. Eight months after HSCT, LV-PGK-coSGSH vectors produced bone marrow SGSH (576% normal activity) similar to LV-CD11b-coSGSH (473%), but LV-CD11b-coSGSH had significantly higher brain expression (11 versus 7%), demonstrating improved brain specificity. LV-CD11b-coSGSH normalized MPSIIIA behavior, brain HS, GM2 ganglioside, and neuroinflammation to WT levels, whereas LV-PGK-coSGSH partly corrected neuropathology but not behavior. We demonstrate compelling evidence of neurological disease correction using autologous myeloid driven lentiviral-HSC gene therapy in MPSIIIA mice.

Outcomes of allogeneic haematopoietic cell transplantation for myelofibrosis in children and adolescents: the retrospective study of the EBMT Paediatric Diseases WP.

This retrospective study evaluated 35 children (median age 5.2 years; range 0.4-18) with myelofibrosis (MF), including 33 with primary myelofibrosis and 2 with secondary myelofibrosis transplanted from matched sibling donor (MSD) (n = 17) or non-MSD (n = 18) between 2000 and 2022. Conditioning was usually chemotherapy-based (n = 33) and myeloablative (n = 32). Fifteen patients received bone marrow (BM), 14 haematopoietic cells (HC) from peripheral blood (PB), and 6 from cord blood (CB). Day +100 acute GvHD II-IV incidence was significantly lower after MSD-haematopoietic cell transplantation (MSD-HCT) than after non-MSD-HCT [18.8% (4.3-41.1) vs 58.8% (31-78.6); p = 0.01]. Six-year non-relapse mortality (NRM) was 18% (7.1-32.8), relapse incidence was 15.9% (5.6-30.9), progression-free survival (PFS) was 66.1% (47-79.7), GvHD-free relapse-free survival was 50% (30.6-66.7), and overall survival (OS) was 71.1% (51.4-84). Six-year PFS and OS were significantly higher after BM transplantation compared to HCT from other sources [85.1% (52.3-96.1) vs 50.8% (26.3-71), p = 0.03, and 90.9% (50.8-98.7) vs 54% (28.1-74.2), p = 0.01, respectively], whereas NRM was significantly lower [0% vs 32% (12.3-53.9); p = 0.02]. This first multicentre study on outcomes of allogeneic HCT in children with myelofibrosis proves feasibility and curative effect of transplantation in these children, suggests that bone marrow transplantation is associated with better outcomes, and indicates the need for further studies.

Adenovirus infections after allogeneic hematopoietic cell transplantation in children and adults: a study from the Infectious Diseases Working Party of the European Society for Blood and Marrow Transplantation.

The objective of the study was the analysis of clinical types, outcomes, and risk factors associated with the outcome of adenovirus (ADV) infection, in children and adults after allo-HCT. A total number of 2529 patients (43.9% children; 56.1% adults) transplanted between 2000 and 2022 reported to the EBMT database with diagnosis of ADV infection were analyzed. ADV infection manifested mainly as viremia (62.6%) or gastrointestinal infection (17.9%). The risk of 1-year mortality was higher in adults (p = 0.0001), and in patients with ADV infection developing before day +100 (p < 0.0001). The 100-day overall survival after diagnosis of ADV infections was 79.2% in children and 71.9% in adults (p < 0.0001). Factors contributing to increased risk of death by day +100 in multivariate analysis, in children: CMV seropositivity of donor and/or recipient (p = 0.02), and Lansky/Karnofsky score <90 (p < 0.0001), while in adults: type of ADV infection (viremia or pneumonia vs gastrointestinal infection) (p = 0.0004), second or higher HCT (p = 0.0003), and shorter time from allo-HCT to ADV infection (p = 0.003). In conclusion, we have shown that in patients infected with ADV, short-term survival is better in children than adults. Factors directly related to ADV infection (time, clinical type) contribute to mortality in adults, while pre-transplant factors (CMV serostatus, Lansky/Karnofsky score) contribute to mortality in children.

Intention-to-treat outcomes utilising a stringent event definition in children and young people treated with tisagenlecleucel for r/r ALL through a national access scheme.

CAR T-cell therapy has transformed relapsed/refractory (r/r) B-cell precursor acute lymphoblastic leukaemia (B-ALL) management and outcomes, but following CAR T infusion, interventions are often needed. In a UK multicentre study, we retrospectively evaluated tisagenlecleucel outcomes in all eligible patients, analysing overall survival (OS) and event-free survival (EFS) with standard and stringent definitions, the latter including measurable residual disease (MRD) emergence and further anti-leukaemic therapy. Both intention-to-treat and infused cohorts were considered. We collected data on feasibility of delivery, manufacture, toxicity, cause of therapy failure and followed patients until death from any cause. Of 142 eligible patients, 125 received tisagenlecleucel, 115/125 (92%) achieved complete remission (CR/CRi). Severe cytokine release syndrome and neurotoxicity occurred in 16/123 (13%) and 10/123 (8.1%), procedural mortality was 3/126 (2.4%). The 2-year intent to treat OS and EFS were 65.2% (95%CI 57.2-74.2%) and 46.5% (95%CI 37.6-57.6%), 2-year intent to treat stringent EFS was 35.6% (95%CI 28.1-44.9%). Median OS was not reached. Sixty-two responding patients experienced CAR T failure by the stringent event definition. Post failure, 1-year OS and standard EFS were 61.2% (95%CI 49.3-75.8) and 55.3% (95%CI 43.6-70.2). Investigation of CAR T-cell therapy for B-ALL delivered on a country-wide basis, including following patients beyond therapy failure, provides clinicians with robust outcome measures. Previously, outcomes post CAR T-cell therapy failure were under-reported. Our data show that patients can be successfully salvaged in this context with good short-term survival.

Cytogenetic abnormalities predict survival after allogeneic hematopoietic stem cell transplantation for pediatric acute myeloid leukemia: a PDWP/EBMT study.

Poor-risk (PR) cytogenetic/molecular abnormalities generally direct pediatric patients with acute myeloid leukemia (AML) to allogeneic hematopoietic stem cell transplant (HSCT). We assessed the predictive value of cytogenetic risk classification at diagnosis with respect to post-HSCT outcomes in pediatric patients. Patients younger than 18 years at the time of their first allogeneic HSCT for AML in CR1 between 2005 and 2022 who were reported to the European Society for Blood and Marrow Transplantation registry were subgrouped into four categories. Of the 845 pediatric patients included in this study, 36% had an 11q23 abnormality, 24% had monosomy 7/del7q or monosomy 5/del5q, 24% had a complex or monosomal karyotype, and 16% had other PR cytogenetic abnormalities. In a multivariable model, 11q23 (hazard ratio [HR] = 0.66, P = 0.03) and other PR cytogenetic abnormalities (HR = 0.55, P = 0.02) were associated with significantly better overall survival when compared with monosomy 7/del7q or monosomy 5/del5q. Patients with other PR cytogenetic abnormalities had a lower risk of disease relapse after HSCT (HR = 0.49, P = 0.01) and, hence, better leukemia-free survival (HR = 0.55, P = 0.01). Therefore, we conclude that PR cytogenetic abnormalities at diagnosis predict overall survival after HSCT for AML in pediatric patients.