Treosulfan for Conditioning in Children and Adolescents Before Hematopoietic Stem Cell Transplantation (HSCT)

Transplantation and immunomodulatio

Enzyme replacement therapy and/or hematopoietic stem cell transplantation at diagnosis in patients with mucopolysaccharidosis type I: results of a European consensus procedure

<p>Abstract</p> <p>Background</p> <p>Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder that results in the accumulation of glycosaminoglycans causing progressive multi-organ dysfunction. Its clinical spectrum is very broad and varies from the severe Hurler phenotype (MPS I-H) which is characterized by early and progressive central nervous system (CNS) involvement to the attenuated Scheie phenotype (MPS I-S) with no CNS involvement. Indication, optimal timing, safety and efficacy of the two available treatment options for MPS I, enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT), are subject to continuing debate. A European consensus procedure was organized to reach consensus about the use of these two treatment strategies.</p> <p>Methods</p> <p>A panel of specialists, including 8 specialists for metabolic disorders and 7 bone marrow transplant physicians, all with acknowledged expertise in MPS I, participated in a modified Delphi process to develop consensus-based statements on MPS I treatment. Fifteen MPS I case histories were used to initiate the discussion and to anchor decisions around either treatment mode. Before and at the meeting all experts gave their opinion on the cases (YES/NO transplantation) and reasons for their decisions were collected. A set of draft statements on MPS I treatment options composed by a planning committee were discussed and revised during the meeting until full consensus.</p> <p>Results</p> <p>Full consensus was reached on several important issues, including the following: 1) The preferred treatment for patients with MPS I-H diagnosed before age 2.5 yrs is HSCT; 2) In individual patients with an intermediate phenotype HSCT may be considered if there is a suitable donor. However, there are no data on efficacy of HSCT in patients with this phenotype; 3) All MPS I patients including those who have not been transplanted or whose graft has failed may benefit significantly from ERT; 4) ERT should be started at diagnosis and may be of value in patients awaiting HSCT.</p> <p>Conclusions</p> <p>This multidisciplinary consensus procedure yielded consensus on the main issues related to therapeutic choices and research for MPS I. This is an important step towards an international, collaborative approach, the only way to obtain useful evidence in rare diseases.</p

Treosulfan–fludarabine–thiotepa-based conditioning treatment before allogeneic hematopoietic stem cell transplantation for pediatric patients with hematological malignancies

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Busulfan/Fludarabine- or Treosulfan/Fludarabine-Based Conditioning Regimen for Patients with Wiskott-Aldrich Syndrome – an EBMT Inborn Errors Working Party and Scetide Study

Introduction Excellent survival rates have been reported after allogeneic haematopoietic stem cell transplantation (HSCT) for Wiskott-Aldrich syndrome (WAS) patients. Recipient age >5 years in MUD HSCT as well as MMFD as donor were negative predictors for outcome. However, the vast majority of HSCTs in previously published studies were performed with (oral) busulfan/cyclophosphamide-based conditioning and in the early 2000 years or before. Objectives To compare OS and EFS after HSCT with either busulfan/fludarabine (BuFlu) ± thiotepa (TT) or treosulfan/fludarabine (TreoFlu) ± TT as recommended for primary immunodeficiencies since 2005 by the inborn errors working party (IEWP) of EBMT and ESID. Methods We performed a retrospective analysis via the EBMT and SCETIDE registries of WAS patients transplanted between 20006 and 2016 with these two regimens. At the time of this interim analysis, 174 patients were included, 92 (53%) with BuFlu±TT and 82 (47%) with TreoFlu±TT conditioning, with a median age of 1.6 years (0.2-30) at HSCT and a median follow-up of 32.9 months (1.5-128.9). Donors were MSD in 30, other MRD in 5, MUD (9/10 or 10/10) in 105, MMUD ( Results Two year overall survival (OS) of the entire cohort was 88.6% (95% c.i. 83.5%-93.6%). There was no significant difference in OS between BuFlu±TT or TreoFlu±TT conditioning (2-year OS 88.1% vs. 89.5%; p=0.7). Patients aged >5 years had a worse OS as compared to those 5 years or younger at HSCT (74.9% vs. 90.8%; p=0.005). The type of donor had no influence on OS: 96.4% for MSD/MFD, 86.8% for MUD/MMUD and 87.7% for MMFD (p=0.4). The rate of complete (≥90%) donor chimerism at last follow-up or before a secondary procedure (if a patient had one) was 41/42 (98%) in the BuFlu±TT group and 21/35 (60%) in the TreoFlu±TT group (p=0.0001). Twenty-six patients required a second procedure: stem cell boost in 4, donor lymphocyte infusion in 9, 2nd HSCT in 15 and splenectomy in 1. The 2-year cumulative incidence (CI) of second procedures was higher at 33.9% in the TreoFlu±TT versus 12.8% in the BuFlu±TT group (p=0.017), and 2-year EFS (events: second procedure or death) was 61.4% in the TreoFlu±TT and 75.0% in the BuFlu±TT group (p=0.2). Grade II-IV acute GVHD had the same incidence in both groups (24.4% vs. 26.3%; p=0.849) and chronic GVHD of any grade was borderline more frequent in the TreoFlu±TT group (17.2% vs 6.7%; p=0.054). Conclusion HSCT with either BuFlu±TT or TreoFlu±TT conditioning reliably cures almost 90% of patients with WAS regardless of donor type. Age >5 years at HSCT remains a negative risk factor. More patients were mixed chimeras and required second procedures after TreoFlu±TT than after BuFlu±TT conditioning. These data confirm the feasibility and efficacy of the regimens currently recommended by the IEWP

Outcome of hematopoietic cell transplantation for DNA double-strand break repair disorders

Background: Rare DNA breakage repair disorders predispose to infection and lymphoreticular malignancies. Hematopoietic cell transplantation (HCT) is curative, but coadministered chemotherapy or radiotherapy is damaging because of systemic radiosensitivity. We collected HCT outcome data for Nijmegen breakage syndrome, DNA ligase IV deficiency, Cernunnos-XRCC4-like factor (Cernunnos-XLF) deficiency, and ataxia-telangiectasia (AT). Methods: Data from 38 centers worldwide, including indication, donor, conditioning regimen, graft-versus-host disease, and outcome, were analyzed. Conditioning was classified as myeloablative conditioning (MAC) if it contained radiotherapy or alkylators and reduced-intensity conditioning (RIC) if no alkylators and/or 150 mg/m(2) fludarabine or less and 40 mg/kg cyclophosphamide or less were used. Results: Fifty-five new, 14 updated, and 18 previously published patients were analyzed. Median age at HCT was 48 months (range, 1.5-552 months). Twenty-nine patients underwent transplantation for infection, 21 had malignancy, 13 had bone marrow failure, 13 received pre-emptive transplantation, 5 had multiple indications, and 6 had no information. Twenty-two received MAC, 59 received RIC, and 4 were infused; information was unavailable for 2 patients. Seventy-three of 77 patients with DNA ligase IV deficiency, Cernunnos-XLF deficiency, or Nijmegen breakage syndrome received conditioning. Survival was 53 (69%) of 77 and was worse for those receiving MAC than for those receiving RIC (P=.006). Most deaths occurred early after transplantation, suggesting poor tolerance of conditioning. Survival in patients with AT was 25%. Forty-one (49%) of 83 patients experienced acute GvHD, which was less frequent in those receiving RIC compared with those receiving MAC (26/56 [46%] vs 12/21 [57%], P=.45). Median follow-up was 35 months (range, 2-168 months). No secondary malignancies were reported during 15 years of follow-up. Growth and developmental delay remained after HCT; immune-mediated complications resolved. Conclusion: RIC HCT resolves DNA repair disorder associated immunodeficiency. Long-term follow-up is required for secondary malignancy surveillance. Routine HCT for AT is not recommended.Peer reviewe

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements