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Inotuzumab Ozogamicin is a CD22-directed antibody conjugated to calicheamicin, approved in adults with relapsed or refractory (R/R) B cell acute lymphoblastic leukemia (BCP-ALL). Patients aged 1–18 years, with R/R CD22 + BCP-ALL were treated at the RP2D of 1.8 mg/m2. Using a single-stage design, with an overall response rate (ORR) ≤ 30% defined as not promissing and ORR > 55% as expected, 25 patients needed to be recruited to achieve 80% power at 0.05 significance level. Thirty-two patients were enrolled, 28 were treated, 27 were evaluable for response. The estimated ORR was 81.5% (95%CI: 61.9–93.7%), and 81.8% (18/22) of the responding subjects were minimal residual disease (MRD) negative. The study met its primary endpoint. Median follow up of survivors was 16 months (IQR: 14.49–20.07). One year Event Free Survival was 36.7% (95% CI: 22.2–60.4%), and Overall Survival was 55.1% (95% CI: 39.1−77.7%). Eighteen patients received consolidation (with HSCT and/or CAR T-cells therapy). Sinusoidal obstructive syndrome (SOS) occurred in seven patients. MRD negativity seemed correlated to calicheamicin sensitivity in vitro, but not to CD22 surface expression, saturation, or internalization. InO was effective in this population. The most relevant risk was the occurrence of SOS, particularly when InO treatment was followed by HSCT.

CD28-based CD19 chimaeric antigen receptor-modified (CAR-)Tcells were recently FDA-approved for adult acute lymphoblastic leukaemia (ALL). We report long-term outcome of 37 children and young adults treated with autologous CD19 CAR-T cells. The complete remission rate was 86%, of which 71% were polymerase chain reaction (PCR) minimal residual disease (MRD)-negative, 14% were MRD-negative by flow cytometry, and 14% were PCR MRD-positive. 26 patients proceeded to subsequent haematopoietic stem cell transplant (HSCT). 11 patients had a CD19-postive relapse (eight post HSCT and three without) and one had a CD19-negative relapse. All relapse events occurred within two years from cell therapy. With a median follow-up of three years, the median event-free survival (EFS) is 17 months and the median overall survival (OS) is not reached. The three-year EFS is 41% and OS is 56%. Patients with5% blasts in the bone marrow prior to lymphodepletion had an inferior EFS. All patients with a PCR MRD-positive result at day 28 had relapsed after CAR-T-cell therapy. A prior HSCT did not significantly affect outcome, but a consolidative transplant after achieving remission improved long-term results. Overall, prelymphodepletion disease burden and molecular MRD negativity following CAR-T cells are predictors of long-term outcome following CD19 CAR-T-cell therapy for ALL.

Patients with single large-scale mitochondrial DNA (mtDNA) deletion syndromes (SLSMDs) usually present with multisystemic disease, either as Pearson syndrome in early childhood or as Kearns-Sayre syndrome later in life. No disease-modifying therapies exist for SLSMDs. We have developed a method to enrich hematopoietic cells with exogenous mitochondria, and we treated six patients with SLSMDs through a compassionate use program. Autologous CD34 + hematopoietic cells were augmented with maternally derived healthy mitochondria, a technology termed mitochondrial augmentation therapy (MAT). All patients had substantial multisystemic disease involvement at baseline, including neurologic, endocrine, or renal impairment. We first assessed safety, finding that the procedure was well tolerated and that all study-related severe adverse events were either leukapheresis-related or related to the baseline disorder. After MAT, heteroplasmy decreased in the peripheral blood in four of the six patients. An increase in mtDNA content of peripheral blood cells was measured in all six patients 6 to 12 months after MAT as compared baseline. We noted some clinical improvement in aerobic function, measured in patients 2 and 3 by sit-to-stand or 6-min walk testing, and an increase in the body weight of five of the six patients suffering from very low body weight before treatment. Quality-of-life measurements as per caregiver assessment and physical examination showed improvement in some parameters. Together, this work lays the ground for clinical trials of MAT for the treatment of patients with mtDNA disorders.

We report the results of national retrospective study of 45 children with hemophagocytic lymphohistiocytosis (HLH) who underwent allogeneic hematopoietic stem-cell transplantation (HSCT) in Israel between the years 2000–2018. Donors were either HLA-matched (n = 26), partially mismatched (n = 7), haploidentical (n = 8), or cord-blood (n = 4). Myeloablative conditioning (MAC) was used in 20 procedures, and reduced-intensity conditioning (RIC) in 25. Forty-two patients engrafted, two had primary graft failure (one successfully retransplanted), one died prior to engraftment, and two developed secondary graft failure. Of the eight patients who had mixed donor chimerism at day 30 (5–95%), five achieved stable mixed or full donor chimerism. The 5-year probabilities of overall survival and event-free survival (EFS) were 86% and 82%, respectively. Five-year EFS was lower for patients receiving RIC compared to MAC (72% vs. 100%, p = 0.018) and following alternative-donor transplant (68% vs. 92% for HLA-matched donors, p = 0.034), mostly due to increased transplant-related mortality (TRM). Thus, both HLA-matched and alternative donor transplant procedures may benefit form a myeloablative conditioning regimen.

This phase 1 study investigated the recommended phase 2 dose (RP2D) of inotuzumab ozogamicin (InO), a CD22-directed antibody-drug conjugate, in pediatric patients with multiple relapsed/refractory (R/R) CD22+ acute lymphoblastic leukemia (ALL). Patients (age ≥1 year or 2 (0.6, 0.4, 0.4 mg/m2) and DL2 was 1.8 mg/m2 (0.8, 0.5, 0.5 mg/m2). Secondary end points included safety, antileukemic activity, and pharmacokinetics. Twenty-five patients (23 evaluable for DLTs) were enrolled. In course 1, the first cohort had 1 of 6 (DL1) and 2 of 5 (DL2) patients who experienced DLTs; subsequent review considered DL2 DLTs to be non–dose-limiting. Dose was de-escalated to DL1 while awaiting protocol amendment to re-evaluate DL2 in a second cohort, in which 0 of 6 (DL1) and 1 of 6 (DL2) patients had a DLT. Twenty-three patients experienced grade 3 to 4 adverse events; hepatic sinusoidal obstruction syndrome was reported in 2 patients after subsequent chemotherapy. Overall response rate after course 1 was 80% (95% confidence interval [CI], 59% to 93%) (20 of 25 patients; DL1: 75% [95% CI, 43% to 95%], DL2: 85% [95% CI, 55% to 98%]). Of the responders, 84% (95% CI, 60% to 97%) achieved minimal residual disease (MRD)-negative complete response, and 12-month overall survival was 40% (95% CI, 25% to 66%). Nine patients received hematopoietic stem cell transplantation or chimeric antigen receptor T cells after InO. InO median maximum concentrations were comparable to simulated adult concentrations. InO was well tolerated, demonstrating antileukemic activity in heavily pretreated children with CD22+ R/R ALL. RP2D was established as 1.8 mg/m2 per course, as in adults. This trial was registered at https://www.clinicaltrialsregister.eu as EUDRA-CT 2016-000227-71. Key Points: • The recommended phase 2 dose of InO for pediatric patients with ALL was established at 1.8 mg/m2 per course. • Of the patients with multiple R/R ALL, 85% reached CR after 1 course of single-agent InO at the RP2D, 100% of whom had MRD negativity.

CAR T-cells are approved for the treatment of relapsed and refractory leukemia and lymphoma. Here, we studied the infectious complications in 88 patients treated with CD28-based CD19 CAR T-cells. Overall, 36 infections were documented in 24 patients within the first month after CAR T-cell infusion: Six events of bacteremia, sixteen focal bacterial infections, and fourteen systemic or localized viral infections. Seven patients had nine infectious episodes beyond the first 30 days of follow-up, including three events of bacteremia, three focal bacterial, two viral and one fungal infection. The presence of neutropenia, neutropenic fever and lack of response to treatment were associated with a higher rate of infections. Children had less severe infections than adults. In a multivariate analysis lack of response to treatment was the only significant risk factor. Overall, the incidence of bacterial infections following CAR T-cells is modest especially in children and in patients responding to therapy.

Relapse of B-cell precursor acute lymphoblastic leukemia (BCP-ALL) may occur in the central nervous system (CNS). Most clinical trials of CAR T-cell therapy excluded patients with active CNS leukemia, partially for concerns of neurotoxicity. Here, we report an international study of fifty-five children and adolescents who received CAR T-cell therapy for relapsed BCP-ALL with CNS involvement at the time of referral. All patients received bridging therapy, 16 still having active CNS disease at the time of lymphodepletion. Twelve patients received CD28-based CAR T-cells, 9 being subsequently treated with allogeneic hematopoietic stem-cell transplantation (allo-HSCT). Forty-three patients received 4-1BB-based CAR T-cells. Cytokine-release syndrome (CRS) and neurotoxicity occurred in 65% and 38% of patients, respectively, more frequently following treatment with CD28-based CARs. Fifty-one of 54 evaluable patients (94%) achieved complete response following this therapy. Relapse occurred in 22 patients: 19/43 following 4-1BB-based CARs (12 CNS relapses), and 3/12 after CD28-based CARs with subsequent HSCT (no CNS relapse). Patients treated with tisagenlecleucel for an isolated CNS relapse had a high incidence of a subsequent CNS relapse (6 of 8). CAR T-cells were found to be effective in this cohort, though the risk of CNS relapse was not completely mitigated by this approach.

Mucormycosis has emerged as an increasingly important cause of morbidity and mortality in immunocompromised patients, but contemporary data in children are lacking. We conducted a nationwide multicentre study to investigate the characteristics of mucormycosis in children with haematological malignancies. The cohort included 39 children with mucormycosis: 25 of 1136 children (incidence 2·2%) with acute leukaemias prospectively enrolled in a centralized clinical registry in 2004-2017, and an additional 14 children with haematological malignancies identified by retrospective search of the databases of seven paediatric haematology centres. Ninety-two percent of mucormycosis cases occurred in patients with acute leukaemias. Mucormycosis was significantly associated with high-risk acute lymphoblastic leukaemia (OR 3·75; 95% CI 1·51-9·37; P = 0·004) and with increasing age (OR 3·58; 95% CI 1·24-9·77; P = 0·01). Fifteen patients (38%) died of mucormycosis. Rhinocerebral pattern was independently associated with improved 12-week survival (OR 9·43; 95% CI 1·47-60·66; P = 0·02) and relapsed underlying malignancy was associated with increased 12-week mortality (OR 6·42; 95% CI, 1·01-40·94; P = 0·05). In patients receiving frontline therapy for their malignancy (n = 24), one-year cumulative mucormycosis-related mortality was 21 ± 8% and five-year overall survival was 70 ± 8%. This largest paediatric population-based study of mucormycosis demonstrates that children receiving frontline therapy for their haematological malignancy are often salvageable.

Haploidntical hematopoietic stem cell transplantation has been increasingly used in recent years for patients without a matched donor. The αβTCR+/CD19+ depletion technique provide a graft that is enriched with CD34 cells, γδ-T-cells and natural killer. The current experience with αβTCR+/CD19+ depleted grafts in pediatric patients with malignant and non-malignant disorders, demonstrated rapid engraftment, improved immune reconstitution and low risk of GVHD. Future studies will need to define the optimal conditioning regimen in order to improve transplant outcome.

Autologous T cells transduced with CD19-directed chimeric antigen receptors have recently been approved by several regulatory agencies for the treatment of relapsed and refractory leukemia and lymphoma, after demonstrating remarkable remission rate in advanced patients. The most common adverse events reported are cytokine-release syndrome (CRS), neurotoxicity, and hematologic toxicity. Here, we focus on early and late cytopenia occurring after CD19 CAR-T cells in 38 patients treated with CD19 CAR-T cells. Neutropenia, thrombocytopenia, and anemia occur frequently (94, 80, and 51%, respectively) after CAR-T cell infusion, and are associated with a biphasic nature, as in 93% of patients hematologic toxicity occurs after 21 days from cell infusion. Late hematologic toxicity was more common in patients with high grade CRS and in patients treated after a recent stem cell transplantation. Interestingly, since these events occur late after the lymphodepleting chemotherapy and after resolution of CRS, we found perturbations in SDF-1 levels to correlate with events of late neutropenia, likely associated with B-cell recovery.

Background: The WHO defined myeloid and lymphoid neoplasms (MLN) with eosinophilia associated with PDGFRB, PDGFRA, FGFR1 rearrangements as a new entity in 2016. PDGFRB-rearranged MLN sensitive to imatinib were described in adult patients. We report the first pediatric patient with PDGFRB-rearranged myeloproliferative disorder associated with T-lymphoblastic lymphoma bearing the t(5; 14)(q33;q32) translocation who was successfully treated with imatinib only. Methods/Aims: Analysis of bone marrow and peripheral blood cells by fluorescent in situ hybridization identified the PDGFRB partner as CCDC88C. Whole genome sequencing of the patient’s DNA identified the exact junction site, confirmed by PCR amplification and Sanger sequencing. A real-time quantitative PCR assay was designed to quantify the fused CCDC88C-PDGFRB product. Results: A 2.5-year-old boy was diagnosed with myeloproliferative disorder and eosinophilia associated with lymphoblastic lymphoma both bearing the CCDC88C-PDGFRB fusion. Imatinib therapy resulted in rapid clinical, hematological, and cytogenetic response. Molecular response to treatment was monitored by a real-time PCR assay specific for the CCDC88C- PDGFRB fusion. Conclusion: This is the first description of MLN with eosinophilia in the pediatric age group. Response to treatment with imatinib only was monitored by specific quantitative PCR assay with sustained remission lasting 5.5 years from diagnosis.

Venous thromboembolism (VTE) is a serious complication of acute lymphoblastic leukemia (ALL) therapy. The aim of this population-based study was to evaluate the rate, risk factors, and long-term sequelae of VTE in children treated for ALL. The cohort included 1191 children aged 1&ndash, 19 years diagnosed with ALL between 2003&ndash, 2018, prospectively enrolled in two consecutive protocols: ALL-IC BFM 2002 and AIEOP-BFM ALL 2009. VTEs occurred in 89 patients (7.5%). Long-term sequelae were uncommon. By univariate analysis, we identified four significant risk factors for VTEs: Severe hypertriglyceridemia (p = 0.005), inherited thrombophilia (p &lt, 0.001), age &gt, 10 years (p = 0.015), and high-risk ALL group (p = 0.039). In addition, the incidence of VTE was significantly higher in patients enrolled in AIEOP-BFM ALL 2009 than in those enrolled in ALL-IC BFM 2002 (p = 0.001). Severe VTE occurred in 24 children (2%), all of whom had at least one risk factor. Elevated triglyceride levels at diagnosis did not predict hypertriglyceridemia during therapy. In a multivariate analysis of 388 children, severe hypertriglyceridemia and inherited thrombophilia were independent risk factors for VTE. Routine evaluation for these risk factors in children treated for ALL may help identify candidates for intervention.

We report the results of national retrospective study of 45 children with hemophagocytic lymphohistiocytosis (HLH) who underwent allogeneic hematopoietic stem-cell transplantation (HSCT) in Israel between the years 2000-2018. Donors were either HLA-matched (n = 26), partially mismatched (n = 7), haploidentical (n = 8), or cord-blood (n = 4). Myeloablative conditioning (MAC) was used in 20 procedures, and reduced-intensity conditioning (RIC) in 25. Forty-two patients engrafted, two had primary graft failure (one successfully retransplanted), one died prior to engraftment, and two developed secondary graft failure. Of the eight patients who had mixed donor chimerism at day 30 (5-95%), five achieved stable mixed or full donor chimerism. The 5-year probabilities of overall survival and event-free survival (EFS) were 86% and 82%, respectively. Five-year EFS was lower for patients receiving RIC compared to MAC (72% vs. 100%, p = 0.018) and following alternative-donor transplant (68% vs. 92% for HLA-matched donors, p = 0.034), mostly due to increased transplant-related mortality (TRM). Thus, both HLA-matched and alternative donor transplant procedures may benefit form a myeloablative conditioning regimen.

Nelarabine is an antineoplastic agent approved for the treatment of relapsed/refractory T-lineage acute lymphoblastic leukaemia (T-ALL) or T-lineage acute lymphoblastic lymphoma (T-LBL). The purpose of this phase 4, multicentre, single-arm, observational, open-label trial was to provide additional data on the safety and efficacy of nelarabine under licensed conditions of use in children and young adults ≤21 years of age. Patients (N = 28) had a mean ± standard deviation age of 11·5 ± 4·6 years; 71% were male and 61% had a diagnosis of T-ALL. Adverse events (AEs) and treatment-related AEs were experienced by 46% and 21%, respectively, and included few haematological AEs and no haematological serious AEs. Neurological AEs from one of four predefined categories (peripheral and central nervous systems, mental status change and uncategorized) were reported in four patients. There were no AE-related treatment discontinuations/withdrawals. The overall response rate was 39.3%: complete response (CR), 35.7%; CR without full haematological recovery (CR*), 3.6%. Post-treatment stem cell transplantation was performed for 46% of the cohort. Median overall survival (OS) was 3·35 months for non-responders and not reached for responders (CR + CR*). The response rate, median OS, and safety profile of nelarabine in this disease setting and population were consistent with those reported previously.

Background: Inotuzumab ozogamicin (InO) was well tolerated and demonstrated anti-leukemia activity in heavily pre-treated pediatric patients (pts) with CD22-positive relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) in the Phase (Ph) I ITCC-059 study. With the established recommended phase 2 dose (RP2D) (1.8 mg/m2/course, as in adults) a consecutive Ph II study has been performed, sponsored by Erasmus MC and supported by Pfizer (NTR57360). Study design: Pts aged 1-18 years with R/R CD22+ BCP-ALL were included after informed consent was obtained. Key inclusion criteria included, M2/M3 marrow and adequate liver and kidney function. Overall response rate (ORR) was the primary endpoint, and included CR, CRp (ANC >500/µL but PLT ≤50.000/µL) and CRi (ANC ≤500/µL and/or PLT ≤50,000/µL). Secondary endpoints included safety, minimal residual disease (MRD) levels and durability of response. The study consisted of a single-stage design to test the null hypothesis (H0) ORR ≤30% and the alternative hypothesis of ORR >55%. With 25 pts, the study had 80% power to reject H0 at a significance level of 0.05. Central MRD analysis by flow cytometry was considered negative if Results: 32 pts were enrolled (Jun 2019-Apr 2020), including 2 screen failures and 2 pts who did not start treatment due to rapidly progressive disease. The median age of the 28 treated pts was 7.5 years (range 1-17); 19 pts were male (68%); 6 (21.5%) were primary refractory, 16 (57%) had ≥2nd relapse and 6 (21.5%) had 1st relapse post-HSCT (median 2 prior regimens, range 2-7). 50% of the pts had received a previous HSCT, 3 (11%) CAR T-cell therapy and 7 (25%) blinatumomab. Median baseline WBC was 3.1 x109/L (range 0.7-132). At time of data snapshot, 48 courses of InO were administered (range 1-4 per pt); one pt was still receiving InO. Disease response was not assessed in 1 pt (discontinued early due to sinusoidal obstruction syndrome (SOS)), 27 pts were evaluable for efficacy analyses. Twenty-two pts achieved a response (ORR 81.5%; 95% CI 61.9%, 93.7%), all after the first cycle (CR n=14, CRp n=1, CRi n=7). Hence, the primary objective was achieved (P-value When combining these results with pts treated at the RP2D in the Ph I study (n=13), 33/40 (82.5%) achieved a response (94% of whom achieved MRD-negativity). Of 9 primary refractory patients included in Ph I and II, 3 (33%) did not respond to InO. The median follow-up time was 7.3 months (mo). The EFS at 6 and 12 mo was 57.9% (95% CI: 40.3−83.3) and 24.8% (95% CI: 9.8−62.9); and OS at 6 and 12 mo was 61.6% (95% CI: 43.3−87.8) and 54.8% (95% CI: 35.9−83.6), respectively. The median EFS was reached at 6.34 mo (95% CI 2.53, NA). The cumulative incidence of non-response or relapse was 32% and 57% at 6 and 12 mo; 3 pts died in CR (2 due to HSCT complications, 1 due to neurological deterioration considered related to previous CNS leukemia and prolonged intrathecal treatment). Nine of 22 responding pts underwent HSCT (median 35 days after the last InO dose, range 20-72); 4 are still in CR. Three responders received consolidation with CAR T (52, 55 and 215 days after last Ino dose), all are still in CR. Four cases of VOD/SOS were reported. One case occurred during InO treatment (gr 3, resolved). Three of 9 transplanted pts (33%) developed post-HSCT SOS. None of these pts received prophylactic defibrotide. One pt, previously transplanted and treated with CAR T, received 1 course of InO prior to a second HSCT and developed SOS (gr 3), ongoing at the time of death due to multiorgan failure. The other 2 pts developed gr 2 SOS after 2 and 3 courses of InO before their first HSCT, both events resolved. All pts had at least 1 adverse event (AE) during the study and 19 pts reported at least 1 of gr 3-4 AE. The most common AE was fever. Detailed data will be presented at the meeting. Conclusion: InO was well tolerated in this Ph II study which confirmed remarkable activity in these heavily pretreated pts. The ORR was 81.5% with 95% MRD-negativity; 55% of pts remained alive after 1 year. Twelve pts proceeded to consolidation treatment (either HSCT or CAR T). In contrast with the Ph I cohort (where no pts developed SOS post 7 HSCTs), 3 cases of SOS were recorded here after 9 HSCTs. A Ph I cohort of this study combining InO with chemotherapy in R/R pediatric ALL is ongoing. Disclosures Brivio: Pfizer Inc.: Other: Erasmus MC received institutional funding for the study from Pfizer. Rossig:BMS: Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; EUSA Pharma: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria. Sleight:Pfizer Inc.: Current Employment. Reinhardt:Novartis: Membership on an entity's Board of Directors or advisory committees; CLS Behring: Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Roche: Research Funding; bluebird bio: Membership on an entity's Board of Directors or advisory committees. von Stackelberg:Morphosys: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau. Zwaan:Servier, Sanofi, Daiichi Sankyo, Novartis, Janssen, Roche, Incyte, Pfizer, Celgene: Consultancy; Pfizer, Celgene, BMS: Research Funding; Jazz Pharmaceuticals: Other: Travel funding.

Haploidntical hematopoietic stem cell transplantation has been increasingly used in recent years for patients without a matched donor. The αβTCR+/CD19+ depletion technique provide a graft that is enriched with CD34 cells, γδ-T-cells and natural killer. The current experience with αβTCR+/CD19+ depleted grafts in pediatric patients with malignant and non-malignant disorders, demonstrated rapid engraftment, improved immune reconstitution and low risk of GVHD. Future studies will need to define the optimal conditioning regimen in order to improve transplant outcome.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the effective mean of immune restoration in severe combined immunodefiency (SCID). Usually, HSCT without cytoreductive conditioning is attempted. Nevertheless, conditioning procedures are still preferred in a subset of patients. Herein, we describe the immunological outcome in a cohort of conditioned and unconditioned patients, from diagnosis, through transplantation, to follow-up. This retrospective study was conducted on 17 patients with SCID (10 conditioned, 7 unconditioned) who later underwent HSCT. Immune reconstitution was assessed in the post-transplant year by quantification of T cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs), among additional laboratory and clinical evaluations. Unconditioned patients were diagnosed and transplanted earlier. TREC and KREC quantification showed a gradual increase in both groups, with higher levels in the conditioned group. Engraftment percentages differed drastically between groups, favoring the conditioned group. Unconditioned patients were significantly more dependent on intravenous immunoglobulins (IVIGs). One patient from each group succumbed to disease complications. Conditioning demonstrated superior laboratorial outcomes. Patients with unique characteristics (i.e., consanguinity, Bacillus Calmette-Guerin vaccination, impaired access to IVIG) may require personalized considerations. The effort to implement secondary prevention of SCID with newborn screening should continue.

BACKGROUND Therapy outcomes for childhood acute lymphoblastic leukemia (ALL) had substantially improved in the last decades, but variability across racial and ethnic groups was identified in some clinical studies. In this study, we aimed to investigate whether such a difference in outcome is found in the diverse ethnicities in Israel as well. METHODS A retrospective study was conducted among 1154 patients (855 Jews, 195 Muslims, 52 Bedouins, 26 Druze, and 26 others) aged 1 to 21 years, who were diagnosed with ALL between 1989 and 2011 and were treated according to the same Berlin-Frankfurt-Muenster-based Israel National Study protocols. RESULTS Bedouins had a higher incidence of t(1;19) (16% vs 3% for non-Bedouins) and a lower incidence of high-hyperdiploidy (10% vs 25% for non-Bedouins) (P = 0.01). Five-year event-free survival (EFS) and overall survival (OS) were poorer for the Bedouins (60.3% ± 7.2% and 63.1% ± 7.2%, respectively) compared with the Jews, Muslims, and Druze (80.4% ± 1.4%, 77.3% ± 3.2%, and 84% ± 7.3%, respectively, for EFS [P = 0.02], and 86.3% ± 1.2%, 82.3% ± 2.9%, and 88.3% ± 6.4%, respectively, for OS [P = 0.002]). Adherence to intensive chemotherapy was similar between the Muslims and the Bedouins. CONCLUSIONS Our findings suggest that the Bedouins, a highly inbred ethnic Arab people, may be considered a higher risk group that may need more intensive chemotherapy and/or supportive care in order to improve their outcome.

Background: CAR T cells targeting CD19 are approved for patients with relapsed or refractory acute lymphoblastic leukemia (ALL), failing two or more prior therapies. The central nervous system (CNS) is a known sanctuary site of ALL. Despite observations of CAR T-cells trafficking to the CNS in patients, most clinical trials excluded patients with active CNS leukemia, partially for concerns of neurotoxicity. Methods: We conducted an international retrospective study of patients who were referred to CAR T-cell therapy for relapsed ALL with CNS involvement. Results: We reviewed data of 27 patients (16 males and 11 females) from 8 centers who were treated with CD19 CAR T-cells for ALL relapse involving the CNS. Fifteen patients had a prior bone marrow transplantation, and in seven total body irradiation was given. Four additional patients received previous cranial radiation. At time of CAR T-cell order or clinical trial inclusion, ten patients had an isolated CNS relapse, and 17 had a combined CNS and marrow relapse. The median number of cells in the CSF of patients at enrollment was 65 (range 0-5670), and 16 of 21 patients who had imaging performed showed leukemia-associated changes in brain MRI. All patients received bridging chemotherapy between enrolment and lymphodepletion, including intrathecal chemotherapy alone or in combination with systemic chemotherapy and/or radiation. At lymphodepletion, 15 patients had cleared CNS disease while 12 had active CNS blasts or imaging lesions. Following lymphodepletion with fludarabine and cyclophosphamide, patients received 2nd-generation CAR T cells: 15 patients treated with a CD19-4-1BB CAR and 12 with a CD19-CD28 CAR. Cytokine release syndrome (CRS) occurred in 20 patients: 12 patients (100%) treated with CD19-CD28 CARs and 8 with CD19-4-1BB CARs (53%, p=0.006). Immune-effector cell neurotoxicity (ICANS) was diagnosed in 11 patients, 9 of 12 following CD28-based CARs, and 3 of 15 following 41BB-based CARs (p=0.004). Patients with active CNS-disease prior to lymphodepletion also had a higher rate of ICANS (75% vs 20%, p=0.004) but not of CRS. One patient died of grade 5 ICANS on day +7 following CD28-based CARs for an isolated CNS relapse. Twenty-four of 26 evaluable patients (92%) had a complete remission following CAR T-cells. Nine patients were further referred to an allogeneic transplant, all following CD28-based CARs. Overall, six patients had relapsed - in four relapse involved bone marrow, and in two the CNS. Conclusions: In this cohort of patients with active CNS disease treated with CD19 CAR T-cells, we report a high remission rate in previously heavily pre-treated patients. Toxicities are significant, and associated mostly with the costimulatory domain of the CAR (CD28>41BB) and the presence of active CNS disease at lymphodepletion. This may be informative when designing future clinical studies of CAR T cell therapy for patients with CNS manifestations of ALL. Disclosures Jacoby: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Lonza: Membership on an entity's Board of Directors or advisory committees. Ghorashian:Novartis: Honoraria; UCLB: Patents & Royalties; Amgen: Honoraria. De Moerloose:Novartis: Consultancy. Rossig:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; EUSA Pharma: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria. von Stackelberg:Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Morphosys: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau. Bourquin:Servier: Other: Travel Support. OffLabel Disclosure: We describe the use of commercial and investigational CAR T-cell products

Background Autologous CD19 chimeric-antigen receptor (CAR) T-cells are an effective salvage therapy for patients with relapsed or refractory B cell malignancies. The essential first step in the production is the collection of mature lymphocytes through leukapheresis. It is a challenging procedure given the fact patients are heavily pretreated and the special considerations of pediatric apheresis. Methods We analyzed the data of leukapheresis outcome for CAR T production in a phase 1b/2 clinical trial enrolling 34 children, adolescents and young adults with relapsed or refractory B-cell malignancies. Results All patients underwent a single leukapheresis. Given a short production time for CAR T-cells, most patients received bridging therapy prior to apheresis. Leukapheresis was performed using peripheral venous access in the majority (82%) of patients, and the remainder required arterial line or central venous access. T-cell collection efficiency (CE) was variable with a median of 18%. No apheresis-related adverse events were noted, and all procedures were successful but two: one resulting in lower than target dose (1 × 106 CAR + cells/kg) and the other in failure of CAR T-cell production. Conclusions Collection of sufficient T-cells in heavily pretreated pediatric patients via a single apheresis procedure is feasible even with relatively low T-cell CE.

Autologous CD19 chimeric-antigen receptor (CAR) T cells demonstrated remarkable remission rates in relapsed and refractory acute lymphoblastic leukemia (R/R ALL). Here, we report results from a phase 1b/2 study of in-house produced CD19 CAR with a CD28 costimulatory domain. Twenty-one patients with R/R ALL were enrolled, and 20 infused. The median age was 11 years (range, 5-48). Patients had a median of 4 prior regimens, including blinatumomab in 6 and prior stem-cell transplantation in 10. In total 8 patients had extramedullary (EM) leukemic involvement, and prior to lymphodepletion and CAR 7 had active lesions, a group underrepresented in previous trials. In vivo expansion of CAR T cells was observed in 18 patients. In total 16 patients developed cytokine release syndrome, and 11 patients developed neurotoxicity, with no toxic deaths. All responding patients were referred to an allogeneic hematopoietic stem-cell transplantation. The remission rate was 90%, including resolution of all refractory EM sites. Four responding patients relapsed, 3 who had a PCR-MRD positive remission at 28 days following CAR-T cells and 1 patient 21 months after an MRD-negative response. The estimated 1-year event-free survival and overall survival are 73% and 90%, respectively. Patients with R/R EM ALL may also benefit from CAR-T cell therapy.

A growing number of pediatric acute lymphoblastic leukemia (ALL) and hematopoietic stem cell transplantation (HSCT) survivors reach adulthood and face long-term health-related problems. We review risk factors and the prevalence of the metabolic syndrome (MetS), a cluster of obesity-related comorbidities, including abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, impaired glucose metabolism, and type 2 diabetes in ALL and HSCT survivors. Components of the MetS are already detected during the first year of ALL maintenance therapy and significantly worsen over time. The prevalence of MetS increases at a faster rate in this setting than in the general population. Factors found to be of the greatest potential risk to the development of the MetS are central obesity, increased BMI, irradiation therapy, older age, poor diet, and low level of physical activity. The early onset of MetS and its components among ALL and HSCT survivors calls for early and continuous screening to identify those at risk and to implement preventive measures.

Summary Ras-associated lymphoproliferative disease (RALD) is an autoimmune lymphoproliferative syndrome (ALPS)-like disease caused by mutations in Kirsten rat sarcoma viral oncogene homologue (KRAS) or neuroblastoma RAS viral (V-Ras) oncogene homologue (NRAS). The immunological phenotype and pathogenesis of RALD have yet to be studied extensively. Here we report a thorough immunological investigation of a RALD patient with a somatic KRAS mutation. Patient lymphocytes were analysed for phenotype, immunoglobulin levels and T cell proliferation capacity. T and B cell receptor excision circles (TREC and KREC, respectively), markers of naive T and B cell production, were measured serially for 3 years. T and B cell receptor repertoires were studied using both traditional assays as well as next-generation sequencing (NGS). TREC and KREC declined dramatically with time, as did T cell receptor diversity. NGS analysis demonstrated T and B clonal expansions and marked restriction of T and B cell receptor repertoires compared to healthy controls. Our results demonstrate, at least for our reported RALD patient, how peripheral T and B clonal expansions reciprocally limit lymphocyte production and restrict the lymphocyte receptor repertoire in this disease. Decreased naive lymphocyte production correlated with a clinical deterioration in our patient's immune status, suggesting that TREC and KREC may be used as an aid in monitoring disease progression. Both the methodologies used here and the conclusions regarding immune homeostasis may be applicable to the research of ALPS and other immune dysregulation syndromes.

Background: Inotuzumab ozogamicin (InO) is an anti-CD22 antibody linked to calicheamicin, approved for relapsed/refractory (R/R) CD22+ B-cell precursor adult acute lymphoblastic leukemia (BCP-ALL) at starting dose of 1.8 mg/m2/course. A phase I study in pediatric patients (pts) is being performed and sponsored by Erasmus MC in collaboration with Pfizer, registered in the Dutch Trial Registry (NTR57360). Study design: Children aged 1-18 years with R/R CD22+ BCP-ALL (ALL) were included after IRB approval and informed consent was obtained. Key inclusion criteria consisted of M2/M3 marrow and adequate liver and kidney function. The study aimed to determine the recommended phase 2 dose (RP2D) of single agent InO; secondary objectives included safety, response and pharmacokinetics (PK). Dose escalation followed the Rolling-6 design, with dose-limiting toxicity (DLT) evaluation during course 1 and defined as delay in hematological (hem) recovery after D42 in responding pts and grade (gr) ≥3 non-hem toxicities >48 hours (or >7 days for liver tests). DL1 was 1.4 mg/m2 (0.6-0.4-0.4 mg/m2). Overall response rate (ORR) was defined as CR, CRp (ANC >0.5x10.9/l but PLT ≤50x10.9/l) and CRi (ANC ≤0.5x10.9/l and/or PLT ≤50,000/µL). Central minimal residual disease (MRD) analysis by flow cytometry and RQ-PCR was considered negative if In the first cohort, 2 patients at DL2 experienced a DLT per protocol definition, however these toxicities were considered non-dose limiting; both pts achieved CR. An IRB-approved amendment allowed repeating the DL1 and DL2 DLT assessment in a 2nd cohort. Survival analysis used the Kaplan-Meier method. Results are based on a database snapshot on June 22, 2019. Results: 25 pts were enrolled (Jan 2017-Apr 2019), median age 11 years (range 1.7-16.9); 3 (12%) were refractory, 15 (60%) ≥2nd relapsed ALL and 7 (28%) 1st relapse post-HSCT (median 2 prior treatment regimens, range 2-7). Eleven (44%) pts were previously transplanted; median baseline WBC 3.5 x109/L (range 0.2-8.6). In total, 46 courses of InO were administered (median 2/pt, range, 1-4). 23 of 25 treated pts were DLT-evaluable. In the first cohort, 1/6 and 2/5 pts at DL1 and DL2 experienced a DLT per protocol definition (transaminases elevation and no hem. recovery), but considered non-dose limiting. After the IRB-approved amendment, in the 2nd cohort, 0/6 and 1/6 pts in DL1 and DL2 had a DLT (no hem recovery). All 25 pts had at least 1 adverse event (AE) in Course 1 [24 gr 3-4]: 20 pts experienced ≥1 gr 3-4 hem AE, 15 pts a gr 3-4 non-hem AE (13 treatment-related, mainly febrile neutropenia/infections and lab abnormalities). Gr 3-4 transaminases elevation related to InO was seen in 3 pts (12%) and bilirubin in 2 (8%) in Course 1. 2 cases of VODs (gr 3-4) were reported after InO, both after follow-up chemotherapy (including HD-MTX) for R/R disease. None of these pts received any HSCT. After Course 1, 75% of pts responded at DL1 and 85% at DL2; ORR 80% (CR n=15, CRp n=1, CRi n=4). MRD was available in 19/20 responding pts: 15 (79%) reached MRD-negative CR as best response (6/9 at DL1 and 9/10 at DL2). Consolidation treatment with HSCT (n=6) or CAR-T cells (n=2) was given a median time of 61 days (range 23-125) after the last InO dose. None of these pts had been previously transplanted. The median follow-up for responding pts was 13.3 months (mos), median duration of response 8 mos (range 1.1-14.0). EFS was 66.7% (95% CI 47.9-93.0) and 33.4% (95% CI: 16.5 − 67.4), while the OS 63.3% (95% CI: 45.8−87.6) and 38.7% (95% CI: 21.3 - 70.4) at 6 and 12 mos, respectively. During follow-up, at relapse 13 pts had material available and sufficient ALL cells for reliable CD22 analysis: 2/13 showed CD22-negativity. After multiple doses, observed Ino medium maximum concentrations in DL1 (n=9) and DL2 (n=5) were 217 and 246 ng.hr/mL, comparable to the simulated adult concentration 234 ng.hr/mL at 1.8 mg/m2 dose. Conclusions: InO was well tolerated and showed remarkable activity in these heavily pretreated pts. The RP2D was established at 1.8 mg/m2/course (0.8-0.5-0.5 mg/m2), confirming the dose used in adults. Two cases of VOD were recorded after follow-up chemotherapy. The ORR was 80%; 79% of responding pts had MRD-negative CR, with 40% of pts being alive after 1 year of follow-up. A phase II single agent study in R/R pediatric ALL is ongoing and a Phase 1 of InO in combination with chemotherapy will start soon. Disclosures Díaz de Heredia: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rossig:Amgen, Celgene,EUSA Pharma, Genetech, Novartis, Roche: Other: advisory board; BMS, Pfizer, Roche: Other: speaker honoraria. van der Velden:Amgen: Honoraria, Research Funding; Jansen: Research Funding; BD Biosciences: Research Funding. van der Sluis:medac: Consultancy; jazz farmaceuticals: Consultancy. Chen:Pfizer Inc.: Employment. Sleight:Pfizer: Employment, Equity Ownership. Nysom:Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Teaching and lectures. Øra:Bayer: Membership on an entity's Board of Directors or advisory committees. Locatelli:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Miltenyi: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees. Zwaan:Novartis: Consultancy; Janssen: Consultancy; Jazz pharmaceuticals: Other: Travel support; Daiichi Sankyo: Consultancy; Servier: Consultancy; Pfizer: Consultancy, Research Funding; BMS: Research Funding; Celgene: Consultancy, Research Funding; Sanofi: Consultancy; Roche: Consultancy; Incyte: Consultancy.

Background As cord blood (CB) is being used frequently as a source for heamtopoetic stem cell transplantation defining risk factors for transplantation outcome is an important issue. Procedure The data of all single unit CB transplantation preformed in Israel from 1992 to 2011 were collected. The risk factors for myeloid engraftment, event free survival (EFS) and overall survival (OS) were studied in 87 children. Results There were 49 children with hematological malignancies and 38 with non-malignant diseases. Cumulative rate of neutrophil recovery was 78.3%, while median time to myeloid recovery was 26 days. The incidence of platelet engraftment at 150 days was 53%, and the median time to platelet recovery was 36 days. ABO blood group matching between CB unit and recipient was associated with superior myeloid engraftment. Acute graft versus host disease of grades II–IV occurred in 33% of the patients. Chronic graft versus host disease occurred in 16% of patients. Probabilities of EFS and OS at 1 year were 45% and 57%, respectively. Factors associated with inferior OS were Rh major mismatch versus matched Rh and transplantation from unrelated donor versus related donor. Conclusions These results indicate that matching of ABO blood groups is an important factor that affects engraftment, and also that Rh matching seem to have an impact on OS, which was not previously described in the setting of CB transplantation. Pediatr Blood Cancer 2013;60:2007–2011. © 2013 Wiley Periodicals, Inc.

We retrospectively evaluated neutrophil engraftment kinetics in 29 single versus nine double unit cord blood transplants (CBTs). All single CBTs were performed in pediatric patients (non-malignant/malignant diseases, 19/10), while all double CBTs were performed in adults (n = 8) and an adolescent (n = 1) with hematological malignancies. Median follow-up time was 2.3 years (range, 0.1-13.5 years). Engraftment was achieved in 69% and 89% of the single and double cord blood (CB) groups, respectively. Similarly, median day of engraftment was not different for the single versus the double CBTs, at 19 and 23 days, respectively, and the neutrophil engraftment kinetics was similar in the two groups. Our data indicate that adults without sufficient nucleated cell doses in a single CB unit may receive two units with similar engraftment kinetics to those of children receiving only a single unit.

Mucormycosis has emerged as an increasingly important infection in patients with hematological malignancies, and is associated with considerable morbidity and mortality. However, contemporary data concerning epidemiology and outcome in children is lacking. Here we report a nationwide multicenter study of mucormycosis among children with hematological malignancies. Between the years 2004-2017, 1136 Israeli children aged ≤18 years with acute leukemias (acute lymphoblastic leukemia (ALL)-941; acute myeloid leukemia (AML)-195) were prospectively enrolled on a centralized clinical registry. Fungal infections, including mucormycosis, were prospectively and retrospectively captured. In addition, all 7 pediatric hematology centers were required to search hospital medical records, microbiology databases, and pathology information systems for cases of mucormycosis. Following central revision, 39 cases of mucormycosis were identified. Patient characteristics: Median age at mucor diagnosis: 13.5 years. Underlying diseases: ALL-27, AML-9, other-3. In 24 patients mucormycosis occurred during frontline therapy of their disease, and in 15 patients at relapse. Known risk factors included stem cell transplantation (SCT)-13 (33%), severe neutropenia-33 (85%) and corticosteroids-26 (67%). Among 20 patients on frontline ALL therapy, mucormycosis was diagnosed during induction in 13 cases, reinduction-6 cases, consolidation-1 case. Twenty-five patients with mucormycosis were enrolled on the national acute leukemia registry (not included: other malignancies, non-Israeli patients, relapsed leukemia with primary diagnosis preceding registry initiation, secondary AML). An analysis of registry cases demonstrated that the incidence of mucormycosis did not significantly increase during the study period. There was no seasonal clustering. Mucormycosis was significantly more common among patients ≥10 years old (4% vs 1%, p=0.004). Among patients on frontline treatment, mucormycosis was significantly more common in high-risk (HR) ALL patients (6%) than in non-HR (1%) or AML (1%) patients (p=0.001). Mucormycosis: Patterns of infection included sinusitis/sino-orbital-16 (41%), rhinocerebral-8 (21%), pulmonary-3 (8%), mandibular -4 (10%), gastrointestinal-1, cutaneous-1, otomastoiditis-1, disseminated-6 (15%). The majority (46%) were caused by Rhizopus spp. EORTC criteria: proven-30, probable-7, possible-2 (pathognomonic radiological findings and molecular diagnosis). Treatment: Nineteen patients were treated with amphotericin B formulations only and 19 received combined antifungal treatment. Nine patients received step-down treatment with posaconazole/ isavuconazole. In addition, 33 patients underwent surgical interventions, 26 underwent 2 procedures or more (range 2-14). Median time from presentation to antifungal treatment-3 days. Outcome: Twenty-one patients died, 15 of mucormycosis, 3 of other toxicities, 3 of leukemia. Factors significantly associated with mortality from mucormycosis were preceding SCT (p=0.01), less than 2 surgical interventions (p=0.0003) and relapsed disease (p=0.006). Eight-year OS of the whole cohort, those on frontline therapy and relapsed patients was 42% (±21%), 70%(±13%), 13%(±66%), respectively. Eight-year cumulative incidence of death from mucormycosis (CIDM) in those subgroups was 40%(±8), 21%(±8), 67% (±13), respectively. To our knowledge, this is the largest population-based study of mucormycosis in children with hematological malignancies. Our study demonstrates that mucormycosis is an age-dependent toxicity, significantly more common in patients ≥10 years of age. A striking finding was the high incidence of mucormycosis among patients on frontline high-risk ALL therapy, a fact which may reflect the increasing intensity of childhood ALL treatment. In a cohort of 24 patients who developed mucormycosis on frontline therapy, including 2 patients with AML and 13 with HR-ALL, 8y-OS was 70% and 8y-CIDM was 21%.The majority of patients in this cohort were salvageable through control of underlying disease, rapid instigation of antifungal treatment, and surgical debridement procedures, albeit in some cases at a price of mutilation and long-term sequelae. Future research should focus on the complex interactions between fungi and host, and on developing novel therapeutic strategies. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

Objective To determine the incidence and clinical consequences of asparaginase-associated lipid abnormalities in children with acute lymphoblastic leukemia (ALL). Methods Sixty-five newly diagnosed children and adolescents aged 0.4–21 years with ALL or lymphoblastic lymphoma were retrospectively evaluated for lipid abnormalities. They were treated according to the ALLIC-BFM 2002 protocol between 2002 and 2005. Fasting cholesterol levels were measured in all patients and triglycerides (TG) in 42/65 patients. Results Prior to treatment, mean cholesterol level was 149 ± 50 mg/dl, and increased to maximal level 274 ± 124 mg/dl during treatment. Mean TG level during treatment was 459 ± 526 mg/dl (range 54–3,009). Twelve patients (28%) had TG levels 1,000 mg/dl. No association was found between TG levels and age or gender. One of the 12 patients with TG >400 mg/dl developed left saggital sinus thrombosis and left frontal lobe infarct. TG level at the time of the event was 2,640 mg/dl. None of the five patients with TG levels >1,000 mg/dl developed pancreatitis. Children with TG levels between 400 and 600 mg/dl were treated by fasting. Fibrates and heparin were added to those with levels >600 mg/dl. Lipid abnormalities normalized in all children upon completion of asparaginase treatment. Conclusions Abnormalities of lipid profile in children with ALL during asparaginase therapy are relatively common. We recommend measuring TG before and during asparaginase treatment. Initiation of conservative treatment could prevent further increase of TG and decrease the risk of potential complications. Pediatr Blood Cancer 2010;54:703–706. © 2010 Wiley-Liss, Inc.

Long-term results of the Israeli National Studies in childhood acute lymphoblastic leukemia: INS 84, 89 and 98

Owing to the increased central nervous system (CNS) relapse risk in T-cell acute lymphoblastic leukaemia (ALL), it is unclear whether preventive cranial radiation (pCRT) can be safely omitted. In this study, pCRT was replaced by extended triple intrathecal therapy (TIT) in prednisone good early responders - medium-risk (MR) group, accounting for 76% of T-ALL patients. From 1989 to 2003, 143 T-ALL patients aged 1-18 years were enrolled in the Israel National Studies (INS) 89 (n = 84) and INS 98 (n = 59) trials, based on ALL-Berlin-Frankfurt-Munster (BFM) 86/90 and ALL-BFM 95 protocols, respectively. Five-year event-free survival (EFS) of the MR group in the INS 89 (n = 60) was 70 +/- 5.9% and the INS 98 (n = 43), 83.7 +/- 5.6% (P = 0.12); the cumulative incidence (CI) of any CNS relapse was 5.0 +/- 2.8% and 2.3 +/- 2.3% (P = 0.50), respectively. There was no difference in outcome between MR patients with a white blood cell count (WBC) >or=100 x 10(9)/l treated with extended TIT (n = 17) or pCRT (n = 10). For all T-ALL patients, 5-year EFS was 61.9 +/- 5.3% in INS 89 and 72.9 +/- 5.8% in INS 98, (P = 0.21); the CI of any CNS relapse was 7.1 +/- 2.8% and 1.7 +/- 1.7% (P = 0.142), respectively. Outcome of T-ALL MR patients given extended TIT in the context of BFM-based protocols with long-term follow-up appeared to be comparable to studies in which a larger proportion of patients was irradiated, and was associated with low risk of CNS relapse, regardless of the WBC.

Purpose: The ETV6 gene has been reported to be fused to a multitude of partner genes in various hematologic malignancies with 12p13 aberrations. Cytogenetic analysis of six cases of childhood acute lymphoblastic leukemia revealed a novel recurrent t(8;12)(q13;p13), suggesting involvement of ETV6. Experimental Design: Fluorescence in situ hybridization was used to confirm the involvement of ETV6 in the t(8;12)(q13;p13) and reverse transcription-PCR was used to identify the ETV6 partner gene. Detailed immunologic characterization was done, and owing to their lineage promiscuity, the leukemic blast cells were analyzed for NOTCH1 mutations. Results: We have identified a novel recurrent t(8;12)(q13;p13), which results in a fusion between the transcriptional repressor ETV6 (TEL) and the transcriptional coactivator NCOA2 (TIF2) in six cases of childhood leukemia expressing both T-lymphoid and myeloid antigens. The ETV6-NCOA2 transcript encodes a chimeric protein that consists of the pointed protein interaction motif of ETV6 that is fused to the COOH terminus of NCOA2, including the cyclic AMP–responsive element binding protein–binding protein (CBP) interaction and the AD2 activation domains. The absence of the reciprocal NCOA2-ETV6 transcript in one of the cases suggests that the ETV6-NCOA2 chimeric protein and not the reciprocal NCOA2-ETV6 is responsible for leukemogenesis. In addition, ETV6-NCOA2 leukemia shows a high frequency of heterozygous activating NOTCH1 mutations, which disrupt the heterodimerization or the PEST domains. Conclusions: The ETV6-NCOA2 fusion may define a novel subgroup of acute leukemia with T-lymphoid and myeloid features, which is associated with a high prevalence of NOTCH1 mutations.

Background Patients with childhood cancer or primary immunodeficiencies (PID) are at high risk for developing pulmonary infections and non-infectious complications. The broad differential diagnoses and the critical condition of these patients often drive physicians to start broad-spectrum antibiotic therapy before a definite diagnostic procedure is performed. A definite diagnosis may be achieved in these situations by fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL). Patients and Methods The records of 58 PIDs and cancer (immunocompromised group) pediatric patients who underwent 62 fiberoptic bronchoscopies between 2000 and 2004 were retrospectively reviewed and compared to 158 non-cancer patients who underwent 182 fiberoptic bronchoscopies during the same period. Results The overall diagnostic rate achieved by macroscopic inspection of purulent secretions or hemorrhage, abnormal cell count, and infectious agent isolation in the immunocompromised patients was 84%. A definite organism was recovered in 53.2% of the patients. Probable infection defined as purulent secretions or abnormal cell count without infectious agent isolation was diagnosed in another 21% of the patients. The rate of complications was 30.6%. In the control group, the overall diagnostic rate was 76.9% (n.s) and an infectious agent was demonstrated in 12.1% (P

Allogeneic stem cell transplantation (SCT) is widely used for treatment of various life-threatening pediatric diseases. It is an intensive process that psychologically affects the whole family. Pediatric donors represent a very unique, underreported, group. The aim of this study is to investigate the sibling donors' and their parents' perspective on the donation process. The cohort included 36 sibling donors and 50 parents of pediatric patients who underwent allogeneic SCT between 1995 and 2010 and were alive at the time of the study. Mean age at donation was 14.78±8.350 years in donors' group and 8.22±4.639 years in parents' group. Data were collected by anonymous questionnaires. Three psychological dimensions were analyzed: donors' personal perspective; donor-recipient interpersonal relationship and the influence of the donation on the family unit. Results showed that the donors experienced a wide range of complex emotional responses, positive and negative, whereas the parents' responses were mainly positive and less complex. This study presents both the sibling donor's and parents' perspective, giving a more complete picture of the donation process within the family. The effects of this intense experience of SCT has a long-term impact on the whole family, indicating the need for follow-up and psychosocial support.

Affymetrix human Hu133A oligonucleotide arrays were used to study the expression profile of CD133+ cord blood (CB) and peripheral blood (PB) using CD133 cell-surface marker. An unsupervised hierarchical clustering of 14,025 valid probe sets showed a clear distinction between the CD133+ cells representing the hematopoietic stem cell (HSC) population and CD133-differentiated cells. Two hundred forty-four genes were found to be upregulated by at least twofold in the CD133-positive cells of both CB and PB compared with the CD133-negative cells. These genes represent the hematopoietic "stemness," whereas the 218 and 304 upregulated genes exclusively in PB and CB, respectively, represent tissue specificity. Some of the stemness genes were also common to HSC genes found to be upregulated in several recently published studies. Among these common stemness genes, we identified several groups of genes that have an important role in hematopoiesis: growth factor receptors, transcription factors, genes that have an important role in development, and genes involved in cell growth. Sixteen selected stemness genes are known to be mutated or abnormally regulated in acute leukemias. It can be suggested that key hematopoietic stemness machinery genes may lead to abnormal proliferation and leukemia upon mutation or change of their expression.

Summary The TEL/AML1 (ETV6/RUNX1) fusion gene is the most common genetic rearrangement in paediatric acute lymphoblastic leukaemia (ALL). Although considered to be a low-risk leukaemia, it is associated with a relapse rate of 10–20%. The coexistence of different subclones at diagnosis, based on polymerase chain reaction (PCR) studies of IG/TCR gene rearrangement, with differential response to chemotherapy, was recently reported in this subtype of ALL. We wished to demonstrate such subclones at diagnosis by a recently developed technique of quantitative multiparametric fluorescence in situ hybridization (FISH). Bone marrow cells from 80 paediatric patients with ALL at diagnosis were analysed for the presence of the TEL/AML1 fusion gene by interphase FISH. Fourteen patients were positive for the translocation. Four of them had several subclones associated with various combinations of additional chromosomal abnormalities. The most striking was an atypical and unexpected hybridization pattern consistent with a submicroscopic deletion of the 5′ region of the AML1 breakpoint. Other abnormalities included TEL deletion, trisomy and tetrasomy 21 as well as double TEL-AML1 fusion. The presence of numerous subclones in about 25% of patients with TEL/AML1+ ALL suggests extensive clonal evolution by the time of diagnosis.

Recent improvements in prognosis necessitate considering the emotional responses of children with malignant diseases and of their parents. This prospective study assessed 20 children and adolescents and their 36 parents within 2 weeks of diagnosis and after 1 and 6 months. Fifty-three percent exhibited moderate to severe posttraumatic symptoms right after diagnosis that decreased significantly after 1 month. Children with high-risk disease reported the most severe symptoms. Unexpectedly, children with low-risk disease exhibited more severe symptoms than those with moderate risk. Depressive symptoms decreased significantly during the period, but anxiety symptoms did not. Moreover, quality of life did not change. Twenty percent of parents exhibited posttraumatic symptoms on initial evaluation. Mothers' symptoms did not change, but fathers' symptoms decreased with those of their children. Several procedures and experiences were identified as causes of traumatic stress responses.

Successful stem cell transplantation for patients with severe combined immunodeficiency (SCID) from matched family donors without conditioning results in engraftment of T lymphocytes. B lymphocytes engraft in only 50% of the cases, while myelopoiesis and erythropoiesis remain of host origin. Full hematopoietic engraftment was reported in one case after bone marrow transplantation without conditioning for a SCID patient. We studied three SCID patients who were transplanted with unmodified mobilized peripheral blood from HLA-identical family sex-mismatched members. They received megadoses of stem cells (18-23 x 10(6)CD34/kg). In contrast to the expected mixed chimerism that usually occurs in the absence of conditioning, we found in our patients 100% donor cell engraftment based on fluorescence in situ hybridization (FISH) and microsatellite techniques. Subset analysis of the engrafted cells using a multiparametric system enabling a combined analysis of morphology, immunophenotyping and FISH showed that both T and B lymphocytes and myeloid cells were of donor origin in two patients, while T lymphocytes and myeloid cells were of donor origin in the third. In the two cases with ABO incompatibility, erythroid engraftment was evidenced by blood group conversion from recipient to donor type. Multilineage donor engraftment is possible in SCID patients even without conditioning.

The mechanisms governing migration and extramedullary dissemination of leukemic cells remain obscure. In this study the migration and in vivo homing to the bone marrow of nonobese diabetic severe combined immunodeficient (NOD/SCID) mice injected with human precursor-B acute lymphoblastic leukemia (ALL) cells in comparison to normal CD34+ progenitors (both cord blood and mobilized peripheral blood) was investigated. Although migration and homing of both cell populations was dependent on stromal cell-derived factor 1 (SDF-1)/CXCR4 interactions, major differences in receptor expression as well as the migratory capacity toward various concentrations of SDF-1 were found. Furthermore, unlike normal CD34+ progenitors, in vivo homing of the leukemic cells was superior when recipient NOD/SCID mice were not irradiated prior to transplantation. In addition, we report differences in the adhesion molecules activated following SDF-1 stimulation, documenting a major role for very late antigen 4 (VLA-4), but not VLA-5 and lymphocyte function-associated antigen-1 (LFA-1), in homing of precursor-B ALL cells. Interestingly, Toxin-B and pertussis toxin inhibited the homing of the leukemic cells but not that of normal CD34+ progenitors or normal CD10+/CD19+ precursor-B cells, revealing differences in CXCR4 signaling pathways that are based on changes that acquired by the leukemic cells. Altogether, our data provide new insights into different SDF-1–induced signaling, activation, and consequent motility between normal CD34+ and precursor-B ALL progenitors, which may lead to improved clinical protocols. (Blood. 2004;103: 2900-2907)

Objective. Allogeneic transplantation is a potentially curative treatment for hematologic malignancies but is associated with a high rate of complications. Busulfan is a common component of pretransplant conditioning but has an erratic and unpredictable bioavailability when administered orally. Intravenous (IV) busulfan was recently introduced into clinical practice. Prior studies showed consistent and predictable drug delivery with tight control of busulfan plasma levels, avoiding over- and under-dosing. This study was designed to define the role of IV busulfan in different transplant and disease settings. Patients and Methods. The study included 43 patients with various hematologic malignancies conditioned with high-dose IV busulfan-containing regimens prior to allogeneic transplantation. The donors were HLA-matched siblings (n=24), matched unrelated (n=14), or 1-antigen mismatched related donors (n=5). Outcome parameters were recorded. Results. Forty-two patients had initial engraftment. The toxicity profile was favorable. No patient developed veno-occlusive disease of the liver. Acute graft-vs-host disease (GVHD) grades II–IV occurred in 18 patients (42%). Six patients died of treatment-related causes, five of complications related to acute GVHD, and only one died of organ toxicity. Actuarial non–relapse-related mortality risk was 10% at day 100 and 18% at 2 years posttransplant. The actuarial 2-year overall survival and disease-free survival (DFS) rates were 63% and 44%, respectively. Disease status other than refractory relapse, myeloid disease, and no severe GVHD posttransplant predicted for longer DFS in a multivariant model. Conclusions. IV busulfan-containing regimens allow consistent engraftment of allografts from related and unrelated donors such that myeloablation is administered with a toxicity profile typical of non-myeloablative conditioning. Favorable outcome was seen in patients with myeloid leukemias and in early or intermediately advanced disease; however, this regimen may not be sufficiently cytoreductive in patients with very advanced or active leukemia and in acute lymphoblastic leukemia. IV busulfan merits further study to better define its role as a preferred substitute for oral busulfan in pretransplant conditioning.

The past decade has brought new technologies to the study of minimal residual disease (MRD) in leukemia. Each of them has limitations and is far from being accurate. Recently, a new multiparametric cell scanning system (Duet) was introduced to the field of MRD detection. This system has the advantage of automatically scanning large numbers of cells and performing combined analysis of morphology and fluorescence in situ hybridization (FISH) on the same cell. We used this system to characterize the lineage and degree of maturation of the cells carrying the minor m-BCR/ABL fusion, in a follow-up of an 8-year-old boy with Philadelphia-positive (Ph(+)) acute lymphoblastic leukemia (ALL). The boy was treated using a high-risk protocol and was closely monitored with FISH analysis for cells carrying the m-BCR/ABL fusion. Consecutive analysis along 2.5 years from remission showed 0.2-4.5% m-BCR/ALB(+) cells in the peripheral blood (PB), which is within the accepted background range for this method. The combined analysis found that all the m-BCR/ABL(+) cells were mature lymphocytes. Because mature lymphocytes have a long life span in the circulation, this finding supports the fact that the patient is in remission. Moreover, since mature differentiated cells have a low proliferative capacity, there is a low risk for relapse.

Background Graft manipulation using selective depletion of αβ-T cells provides a source of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) enriched in effector cells. We report our experience implementing this haplo-HSCT for high-risk malignancies in pediatric patients focusing on the conditioning regimen. Procedure We performed a retrospective study of patients who underwent T-cell receptor αβ-depleted haplo-HSCT for high-risk pediatric malignancies. Results Eighteen patients underwent haplo-HSCT using this method. The initial reduced-toxicity chemotherapy-based conditioning regimen was given to eight patients, and resulted in a high rate of graft rejections (six of eight patients). Thus, total body irradiation (TBI) based regimen was introduced in the following 10 patients and resulted in engraftment in all patients. Neutrophil and platelet engraftment were rapid (median time to engraft, 10 days and 12 days, respectively). Significant treatment-related complications for both cohorts were all due to graft failure in patients receiving chemotherapy-based conditioning, with a treatment-related mortality rate of 17%. None of the patients developed hepatic sinusoidal-obstruction syndrome, and no grade III–IV acute graft versus host disease (GVHD) was observed. The majority of patients were free of immunosuppression in the first 100 days post-HSCT, and only two patients developed chronic GVHD. The cumulative incidence of relapse was 39%. Compared to patients conditioned with chemotherapy, patients conditioned with TBI had superior actuarial overall survival (66% vs. 37%, P = 0.05) and event-free survival (61% vs. 33%, P = 0.04). Conclusions A TBI-based conditioning for haplo-HSCT using αβ-T-cell depletion for malignant diseases ensured engraftment and resulted in acceptable outcomes.

Metabolic syndrome (MetS) is a known complication after hematopoietic stem cell transplantations (HSCT) that contributes to long-term morbidity. We assessed the prevalence of components of the MetS in pediatric survivors of allogeneic HSCT and identified associated risk factors. Thirty-eight patients, median age at HSCT, 8.5 years, were evaluated at a median of 3.9 years post-HSCT. Overweight or obesity was seen in 23.7% of the patients, 15.8% had hypertension, 15.8% had hypertriglyceridemia, and 13% had low high-density lipoprotein cholesterol levels according to age and gender. Four (10.5%) met the criteria of MetS; all were transplanted for malignant disease. Twelve patients (31.6%) had at least one component of the MetS. The 5-year probability of developing components of the MetS revealed that patients with BMI-Z score ≥0 at HSCT were significantly at higher risk than those with lower BMI-Z. Patients who developed components of the MetS had higher levels of insulin, homeostasis model assessment, uric acid, leptin, and lower adiponectin levels. Multivariable regression analysis revealed that BMI-Z-score >1.036 at time of evaluation was associated with 4.3-fold increased risk (P=.050) and adiponectin levels ≤6 μg/mL were associated with 6.7-fold increased risk of develop components of the MetS (P=.007). Overweight and obesity and adiponectin levels may be useful as markers in HSCT survivors.