Management of adults and children receiving CAR T-cell therapy: 2021 best practice recommendations of the European Society for Blood and Marrow Transplantation (EBMT) and the Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association (EHA).

BACKGROUND: Several commercial and academic autologous chimeric antigen receptor T-cell (CAR-T) products targeting CD19 have been approved in Europe for relapsed/refractory B-cell acute lymphoblastic leukemia, high-grade B-cell lymphoma and mantle cell lymphoma. Products for other diseases such as multiple myeloma and follicular lymphoma are likely to be approved by the European Medicines Agency in the near future. DESIGN: The European Society for Blood and Marrow Transplantation (EBMT)-Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association collaborated to draft best practice recommendations based on the current literature to support health care professionals in delivering consistent, high-quality care in this rapidly moving field. RESULTS: Thirty-six CAR-T experts (medical, nursing, pharmacy/laboratory) assembled to draft recommendations to cover all aspects of CAR-T patient care and supply chain management, from patient selection to long-term follow-up, post-authorisation safety surveillance and regulatory issues. CONCLUSIONS: We provide practical, clinically relevant recommendations on the use of these high-cost, logistically complex therapies for haematologists/oncologists, nurses and other stakeholders including pharmacists and health sector administrators involved in the delivery of CAR-T in the clinic.

Metabolic syndrome and cardiovascular disease after haematopoietic cell transplantation (HCT) in adults: an EBMT cross-sectional non-interventional study.

Metabolic syndrome (MetS) is associated with cardiovascular disease in the general population and is also a potential cardiovascular risk factor in survivors of haematopoietic cell transplantation (HCT). We report an EBMT cross-sectional, multi-centre, non-interventional study of 453 adult HCT patients surviving a minimum of 2 years post-transplant attending routine follow-up HCT and/or late effects clinics in 9 centres. The overall prevalence of MetS was 37.5% rising to 53% in patients >50 years of age at follow-up. There were no differences in rates of MetS between autologous and allogeneic HCT survivors, nor any association with graft-versus-host disease (GvHD) or current immunosuppressant therapy. Notably, there was a significantly higher occurrence of cardiovascular events (CVE, defined as cerebrovascular accident, coronary heart disease or peripheral vascular disease) in those with MetS than in those without MetS (26.7% versus 9%, p < 0.001, OR 3.69, 95% CI 2.09-6.54, p < 0.001), and, as expected, MetS and CVE were age-related. Unexpectedly, CVE were associated with occurrence of second malignancy. Screening for and management of MetS should be integrated within routine HCT long-term follow-up care for both allogeneic and autologous HCT survivors. Further research is warranted, including randomised controlled trials of interventional strategies and mechanistic studies of cardiovascular risk in HCT survivors.

Impact of patient: donor HLA disparity on reduced-intensity-conditioned allogeneic stem cell transplants from HLA mismatched unrelated donors for AML: from the ALWP of the EBMT.

Patients with acute myeloid leukaemia (AML) who lack a matched sibling or unrelated donor commonly undergo transplantation from a donor matched at 9/10 HLA-A, -B, -C, -DRB1, -DQB1 alleles, and it is unclear if a specific locus mismatch is preferable to any other. We therefore studied 937 patients with AML in complete remission transplanted using a reduced intensity conditioning regimen from an unrelated donor mismatched at a single allele. In a multivariate analysis, patient age, adverse karyotype and patient cytomegalovirus (CMV) seropositivity were correlated with decreased leukaemia free survival (LFS) and overall survival (OS). There was no significant difference in LFS or OS between patients transplanted from donors mismatched at HLA-A, -B, -C or -DRB1 in comparison to a HLA-DQB1 mismatched transplant. In a multivariate analysis, patients transplanted with a HLA-A mismatched donor had higher rates of acute graft-versus-host disease (GVHD) and non-relapse mortality (NRM) than patients transplanted with a HLA-DQB1 mismatched donor. Patient CMV seropositivity was associated with an increase in NRM and acute GVHD and reduced LFS and OS, regardless of donor CMV status. For CMV seropositive patients lacking a fully matched donor, alternative GVHD and CMV prophylaxis strategies should be considered.

Nilotinib in steroid-refractory cGVHD: prospective parallel evaluation of response, according to NIH criteria and exploratory response criteria (GITMO criteria).

We conducted a phase I-II study to evaluate Nilotinib (NIL) safety and pharmacokinetics in 22 SR-cGVHD patients; we also evaluated ORR by using in parallel NIH criteria and an exploratory approach, combining objective improvement (OI) without failure criteria (GITMO criteria). Results: 22 patients were enrolled. After dose escalation up to 600 mg/day, MTD was not reached. Main toxicities were asthenia, headache, nausea, pruritus, cramps, and mild anemia. Mean and median plasma concentrations of NIL (C-NIL) were 817 (SD ± 450) and 773 ng/ml. ORR at 6 months, according to 2005 and 2014 NIH and GITMO criteria were 27.8%, 22.2%, and 55.6% respectively; close correspondence has been observed for ORR, according to 2014 NIH criteria, both assessed in a conventional way and assisted by dedicated software (CROSY). At 48 months OS was 75% while FFS, according to NIH and GITMO criteria, was 30 and 25%. In conclusion the safety profile of NIL and long-term outcome makes NIL an attractive option in SR-cGVHD. Exploratory GITMO criteria could represent an alternative tool for easy response evaluation in patients with prevalent skin and lung involvement, but require validation in a larger population; CROSY software showed excellent reliability in capturing ORR according to the 2014 NIH criteria.

Postremission Consolidation by Autologous Hematopoietic Cell Transplantation (HCT) for Acute Myeloid Leukemia in First Complete Remission (CR) and Negative Implications for Subsequent Allogeneic HCT in Second CR: A Study by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT).

After autologous hematopoietic cell transplantation (HCT) in the first complete remission (CR1), patients with acute myeloid leukemia (AML) may relapse and undergo allogeneic HCT in the second complete remission (CR2). The aim of this study was to analyze the outcome of allogeneic HCT performed in CR2 comparing patients with prior consolidation by autologous HCT versus patients with chemotherapy consolidation. Included were 2619 adults with allogeneic HCT in CR2 from 2000 to 2017 with (n = 417) or without (n = 2202) prior autologous HCT. Patient groups were not entirely comparable; patients with prior autologous HCT were younger, had less often a favorable cytogenetic profile, had more commonly donors other than matched siblings, and more often received reduced-intensity conditioning. In multivariate analysis, nonrelapse mortality risks in patients with prior autologous HCT were 1.34 (1.07 to 1.67; P = .01) after adjustment for age, cytogenetic risk, transplant year, donor, conditioning intensity, sex matching, interval diagnosis-relapse, and relapse-allogeneic HCT as compared with chemotherapy consolidation. Similarly, risks of events in leukemia-free survival and graft-versus-host disease, relapse-free survival were higher with prior autologous HCT, 1.17 (1.01 to 1.35), P = .03 and 1.18 (1.03 to 1.35), P = .02, respectively. Risk of death was also higher, 1.13 (0.97 to 1.32), P = .1, but this was not significant. Postremission consolidation with autologous HCT for AML in CR1 increases toxicity of subsequent allogeneic HCT in CR2.

EBMT prospective observational study on allogeneic hematopoietic stem cell transplantation in T-prolymphocytic leukemia (T-PLL).

Preliminary data suggest that allogeneic stem cell transplantation (allo-SCT) may be effective in T-prolymphocytic leukemia (T-PLL). The purpose of the present observational study was to assess the outcome of allo-SCT in patients aged 65 years or younger with a centrally confirmed diagnosis of T-PLL. Patients were consecutively registered with the EBMT at the time of transplantation and followed by routine EBMT monitoring but with an extended dataset. Between 2007 and 2012, 37 evaluable patients (median age 56 years) were accrued. Pre-treatment contained alemtuzumab in 95% of patients. Sixty-two percent were in complete remission (CR) at the time of allo-SCT. Conditioning contained total body irradiation with 6 Gy or more (TBI6) in 30% of patients. With a median follow-up of 50 months, the 4-year non-relapse mortality, relapse incidence, progression-free (PFS) and overall survival were 32, 38, 30 and 42%, respectively. By univariate analysis, TBI6 in the conditioning was the only significant predictor for a low relapse risk, and an interval between diagnosis and allo-SCT of more than 12 months was associated with a lower NRM. This study confirms for the first time prospectively that allo-SCT can provide long-term disease control in a sizable albeit limited proportion of patients with T-PLL.

Trends in patient outcome over the past two decades following allogeneic stem cell transplantation for acute myeloid leukaemia: an ALWP/EBMT analysis.

BACKGROUND: Outcomes for patients with acute myeloid leukaemia (AML) undergoing allogeneic stem cell transplantation (allo-SCT) have significantly improved in recent years. OBJECTIVES: To assess the incremental improvement of transplanted AML patients in the last two decades. METHODS: Patients included in this analysis were adult AML patients who underwent allo-SCT from an HLA-matched sibling donor (MSD) or HLA-matched unrelated donor (MUD) in first remission. Patient outcomes were assessed between three cohorts according to the year of transplant (1993-2002, 2003-2007 and 2008-2012). RESULTS: The analysis comprised a total of 20 187 patients of whom 4763 were transplanted between 1993 and 2002, 5835 in 2003 and 2007, and 9589 in 2008 and 2012. In multivariate analysis, leukaemia-free survival (LFS) rates were significantly improved in more recently transplanted patients compared to patients transplanted in 1993-2002 [Hazard ratio (HR) = 0.84, confidence interval (CI) 95%, 0.77-0.92; P = 0.003], a benefit which also extended to improved overall survival (OS; HR = 0.8, CI 95%, 0.73-0.89; P < 0.0001), and decreased nonrelapse mortality (NRM) rates (HR = 0.65, CI 95%, 0.56-0.75; P < 0.0001). Subset analysis revealed that in MSD, the rates of LFS, NRM and OS significantly improved in patients in the more recent cohort with similar results also seen in MUD. Finally, the incidence of acute graft-versus-host disease (GVHD) was significantly reduced leading to improved GVHD-free/relapse-free survival (GRFS) rates in more recently transplanted patients. CONCLUSION: Outcome of allo-SCT for AML patients has markedly improved in the last two decades owing to decreased nonrelapse mortality and improved rates of leukaemia-free survival resulting in significantly longer survival.

Cord blood transplantation is associated with good outcomes in secondary Acute Myeloid Leukaemia in first remission.

BACKGROUND: We conducted a retrospective survey within the European Society for Blood and Marrow Transplantation (EBMT) registry to assess the outcomes of cord blood transplantation (CBT) in secondary acute myeloid leukaemia (sAML). METHODS: Inclusion criteria consisted of ≥18 years of age, sAML, first CBT between 2002 and 2016, and either first complete remission (CR) or active disease at CBT. RESULTS: One hundred forty-six patients met the study inclusion criteria. Status at transplantation was first CR (n = 97), primary refractory sAML (n = 30) or relapsed (n = 19) sAML. Neutrophil engraftment was achieved in 118 patients while the remaining 25 patients (17%) failed to engraft. This includes 13% of patients transplanted in first CR versus 30% of those transplanted with active disease (P = 0.008). Two-year incidences of relapse were 25% in first CR patients versus 36% in those with advanced disease (P = 0.06) while 2-year incidences of nonrelapse mortality were 35% and 49% (P = 0.03), respectively. At 2-year overall survival, leukaemia-free survival and graft-versus-host disease (GVHD)-free relapse-free survival were 42% vs. 19% (P < 0.001), 40% vs. 16% (P < 0.001), and 26% vs. 12% (P = 0.002) in first CR patients versus those with advanced disease, respectively. CONCLUSIONS: We report here the first study of CBT in a large cohort of sAML patients. Main observation was that CBT rescued approximately 40% of patients with sAML in first CR.

Pure sinusoidal photo-modulation using an acousto-optic modulator.

We use an arbitrary waveform generator to generate a clean sinusoidal modulation from the otherwise nonlinear acousto-optic modulator (AOM). A closed loop optimization script is applied to reduce high order harmonic distortion to less than 0.05% in a high AOM diffraction efficiency regime. This low level of distortion allows us to measure the nonlinear response to photoexcitation of many materials. We demonstrate this technique in a pump-probe experiment to measure the Nonlinear Photo-Modulated Reflectivity (NPMR) of surfaces. NPMR served us as the basis for developing super-resolution microscopy for non-fluorescence samples (label-free) as well as a tool in studying the ultrafast nonlinear response of photo-excited plasmonic nano-structures. Our methodology could be applied to other imaging systems in which measuring nonlinearity is desirable, such as fluorescence and photoacoustic microscopy.

Distinct factors determine the kinetics of disease relapse in adults transplanted for acute myeloid leukaemia.

BACKGROUND: Disease recurrence remains the major cause of death in adults with acute myeloid leukaemia (AML) treated using either intensive chemotherapy (IC) or allogenic stem cell transplantation (allo-SCT). AIMS: The timely delivery of maintenance drug or cellular therapies represent emerging strategies with the potential to reduce relapse after both treatment modalities, but whilst the determinants of overall relapse risk have been extensively characterized the factors determining the timing of disease recurrence have not been characterized. MATERIALS AND METHODS: We have therefore examined, using a series of sequential landmark analyses, relapse kinetics in a cohort of 2028 patients who received an allo-SCT for AML in CR1 and separately 570 patients treated with IC alone. RESULTS: In the first 3 months after allo-SCT, the factors associated with an increased risk of relapse included the presence of the FLT3-ITD (P < 0.001), patient age (P = 0.012), time interval from CR1 to transplant (P < 0.001) and donor type (P = 0.03). Relapse from 3 to 6 months was associated with a higher white cell count at diagnosis (P = 0.001), adverse-risk cytogenetics (P < 0.001), presence of FLT3-ITD mutation (P < 0.001) and time interval to achieve first complete remission (P = 0.013). Later relapse was associated with adverse cytogenetics, mutated NPM1, absence of chronic graft-versus-host disease (GVHD) and the use of in vivo T-cell depletion. In patients treated with IC alone, the factors associated with relapse in the first 3 months were adverse-risk cytogenetics (P < 0.001) and FLT3-ITD status (P = 0.001). The factors predicting later relapse were the time interval from diagnosis to CR1 (P = 0.22) and time interval from CR1 to IC (P = 0.012). DISCUSSION AND CONCLUSION: Taken together, these data provide novel insights into the biology of disease recurrence after both allo-SCT and IC and have the potential to inform the design of novel maintenance strategies in both clinical settings.

What is the outcome in patients with acute leukaemia who survive severe acute graft-versus-host disease?

BACKGROUND: Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic haematopoietic stem cell transplantation (HSCT). With new promising therapies, survival may improve for severe aGVHD. OBJECTIVES: We wanted to analyze the long-term outcome in patients who survive severe aGVHD. METHODS: This study was a landmark analysis of 23 567 patients with acute Leukaemia who survived for more than 6 months after HSCT, 2002-2014. Patients alive after severe aGVHD (n = 1738) were compared to controls. RESULTS: Patients with severe aGVHD had higher non-relapse mortality (NRM) and higher rate of extensive chronic GVHD (cGVHD) than the controls (P < 10-5 ). The probability of relapse was significantly lower in the severe aGVHD group, but Leukaemia-free survival (LFS) and overall survival were significantly lower than for the controls (P < 10-5 ). Five-year LFS in patients with severe aGVHD was 49%, as opposed to 61% in controls with no or mild GVHD and 59% in patients with moderate GVHD. CONCLUSIONS: HSCT patients who survive severe aGVHD have higher risk of developing extensive cGVHD, a higher NRM, a lower relapse probability, and lower LFS than other HSCT patients. This study is a platform for outcome analysis in patients treated with novel therapies for acute GVHD.

Occurrence of graft-versus-host disease increases mortality after umbilical cord blood transplantation for acute myeloid leukaemia: a report from Eurocord and the ALWP of the EBMT.

BACKGROUND: The efficacy of umbilical cord blood transplantation (UCBT) as treatment for acute myeloid leukaemia (AML) relies on immune-mediated graft-versus-leukaemia effects. Previous studies have suggested a strong association between graft-versus-host disease (GVHD) occurrence and graft-versus-leukaemia effects after allogeneic hematopoietic cell transplantation. METHODS: Here, we evaluated the kinetics of relapse rate in correlation with GVHD occurrence after UCBT. The kinetics of relapse rate over time in correlation to GVHD occurrence were assessed by calculating the relapse rate per patient-year within sequential 90-day intervals. The impact of GVHD on relapse and mortality was further studied in multivariate Cox models handling GVHD as a time-dependent covariate. RESULTS: The study included data from 1068 patients given single (n = 567) or double (n = 501) UCBT. The proportion of patients with grade II, III and IV acute GVHD was 20%, 7% and 4%, respectively. At 2 years, the cumulative incidence of chronic GVHD was 42%, the cumulative incidence of relapse was 32%, and overall survival was 32% as well. Relapse rates declined gradually over time during the first 30 months after transplantation. There was a possible suggestion that grade II-IV acute (HR = 0.8, P = 0.1) and chronic (HR = 0.65, P = 0.1) GVHD decreased relapse risk. However, grade II-IV acute GVHD significantly increased early (the first 18 months after UCBT) mortality (HR = 1.3, P = 0.02), whilst chronic GVHD increased each early (HR = 2.7, P < 0.001) and late (HR = 4.9, P < 0.001) mortality after UCBT. CONCLUSIONS: The occurrence of grade II-IV acute or chronic GVHD each increases overall mortality after UCBT for AML mitigating the possible graft-versus-leukemia effect of GVHD.

Low Protein Z levels in patients with plasma cell neoplasms are inversely correlated with IL-6 levels.

Patients with multiple myeloma (MM) have an increased thrombotic risk, but pathogenesis remains uncertain. Low levels of Protein Z (PZ), a vitamin K-dependent plasma protein, are associated with venous as well as arterial thrombosis. The purpose of this study was to analyze PZ levels in patients with plasma cell neoplasms. PATIENTS AND METHODS: The study consisted of 64 plasma cells neoplasm patients and 42 healthy individuals. Clinical investigations included measurement of plasma PZ and IL-6 levels. RESULTS: PZ levels in patients with plasma cell neoplasms were significantly lower compared to healthy controls in the entire cohort (1392±659 vs.2010±603ng/mL, P<0.01), as well as in specific disease subgroups; symptomatic MM (1428±652ng/mL, p<0.01), smoldering MM (1437±883ng/mL, p=0.045) and monoclonal gammopathy of undetermined significance (MGUS) (1247±593ng/mL, p=0.01). PZ was negatively correlated with IL-6 levels in MM patients (r=-0.7, P<0.01). There was no significant difference in PZ levels between patients with or without thrombotic event. CONCLUSION: Plasma cell neoplasm patients have low levels of PZ. This is presumably related to the increased IL-6 production by the bone marrow microenvironment, and could have a potential role in the increased thrombotic tendency in those patients.

Allogeneic haematopoietic stem cell transplant in patients with lower risk myelodysplastic syndrome: a retrospective analysis on behalf of the Chronic Malignancy Working Party of the EBMT.

This corrects the article DOI: 10.1038/bmt.2016.266.

Conditioning regimens for allogeneic hematopoietic stem cell transplants in acute myeloid leukemia.

AML is currently the first indication for allogeneic hematopoietic stem cell transplantation (allo-HSCT), as shown by international transplant registries. The conditioning regimens are classified as myeloablative conditioning, non-myeloablative or reduced intensity conditioning. Targeted radioimmunotherapy such as anti-CD45 antibody have also been added to the conditioning regimen in an attempt to improve tumor cell kill. Refinement of standard regimens has led to a reduction of non-relapse mortality, also in the older age group over 60 or 70 years of age. Relapse post allo-HSCT remains an important issue, especially for patients who undergo transplant with residual or refractory disease. In these patients, pre- and post-transplant interventions need to be considered.

Alloreactivity: the Janus-face of hematopoietic stem cell transplantation.

Differences in major and minor histocompatibility antigens between donor and recipient trigger powerful graft-versus-host reactions after allogeneic hematopoietic stem cell transplantation (HSCT). The clinical effects of alloreactivity present a Janus-face: detrimental graft-versus-host disease increases non-relapse mortality, beneficial graft-versus-malignancy may cure the recipient. The ultimate consequences on long-term outcome remain a matter of debate. We hypothesized that increasing donor-recipient antigen matching would decrease the negative effects, while preserving antitumor alloreactivity. We analyzed retrospectively a predefined cohort of 32 838 such patients and compared it to 59 692 patients with autologous HSCT as reference group. We found a significant and systematic decrease in non-relapse mortality with decreasing phenotypic and genotypic antigen disparity, paralleled by a stepwise increase in overall and relapse-free survival (Spearman correlation coefficients of cumulative excess event rates at 5 years 0.964; P<0.00; respectively 0.976; P<0.00). We observed this systematic stepwise effect in all main disease and disease-stage categories. The results suggest that detrimental effects of alloreactivity are additive with each step of mismatching; the beneficial effects remain preserved. Hence, if there is a choice, the best match should be donor of choice. The data support an intensified search for predictive genomic and environmental factors of 'no-graft-versus-host disease'.

The CXCR4 inhibitor BL-8040 induces the apoptosis of AML blasts by downregulating ERK, BCL-2, MCL-1 and cyclin-D1 via altered miR-15a/16-1 expression.

CXCR4 is a key player in the retention and survival of human acute myeloid leukemia (AML) blasts in the bone marrow (BM) microenvironment. We studied the effects of the CXCR4 antagonist BL-8040 on the survival of AML blasts, and investigated the molecular mechanisms by which CXCR4 signaling inhibition leads to leukemic cell death. Treatment with BL-8040 induced the robust mobilization of AML blasts from the BM. In addition, AML cells exposed to BL-8040 underwent differentiation. Furthermore, BL-8040 induced the apoptosis of AML cells in vitro and in vivo. This apoptosis was mediated by the upregulation of miR-15a/miR-16-1, resulting in downregulation of the target genes BCL-2, MCL-1 and cyclin-D1. Overexpression of miR-15a/miR-16-1 directly induced leukemic cell death. BL-8040-induced apoptosis was also mediated by the inhibition of survival signals via the AKT/ERK pathways. Importantly, treatment with a BCL-2 inhibitor induced apoptosis and act together with BL-8040 to enhance cell death. BL-8040 also synergized with FLT3 inhibitors to induce AML cell death. Importantly, this combined treatment prolonged the survival of tumor-bearing mice and reduced minimal residual disease in vivo. Our results provide a rationale to test combination therapies employing BL-8040 and BCL-2 or FLT3 inhibitors to achieve increased efficacy of these agents.

Use of haploidentical stem cell transplantation continues to increase: the 2015 European Society for Blood and Marrow Transplant activity survey report.

Hematopoietic stem cell transplantation (HSCT) is an established procedure for many acquired and congenital disorders of the hematopoietic system. A record number of 42 171 HSCT in 37 626 patients (16 030 allogeneic (43%), 21 596 autologous (57%)) were reported by 655 centers in 48 countries in 2015. Trends include continued growth in transplant activity over the last decade, with the highest percentage increase seen in middle-income countries but the highest absolute growth in the very-high-income countries in Europe. Main indications for HSCT were myeloid malignancies 9413 (25%; 96% allogeneic), lymphoid malignancies 24 304 (67%; 20% allogeneic), solid tumors 1516 (4%; 3% allogeneic) and non-malignant disorders 2208 (6%; 90% allogeneic). Remarkable is the decreasing use of allogeneic HSCT for CLL from 504 patients in 2011 to 255 in 2015, most likely to be due to new drugs. Use of haploidentical donors for allogeneic HSCT continues to grow: 2012 in 2015, a 291% increase since 2005. Growth is seen for all diseases. In AML, haploidentical HSCT increases similarly for patients with advanced disease and for those in CR1. Both marrow and peripheral blood are used as the stem cell source for haploidentical HSCT with higher numbers reported for the latter.

Risk of sinusoidal obstruction syndrome in allogeneic stem cell transplantation after prior gemtuzumab ozogamicin treatment: a retrospective study from the Acute Leukemia Working Party of the EBMT.

Gemtuzumab ozogamicin (GO) may increase the risk of sinusoidal obstruction syndrome (SOS) when used prior to allogeneic stem cell transplantation (HSCT). We assessed SOS incidence and outcomes after HSCT of 146 adults, with a median age of 50 years, previously receiving GO. SOS prophylaxis was used in 69 patients (heparin n=57, ursodeoxycholic acid n=8, defibrotide n=4). Cumulative incidence (CI) of SOS was 8% (n=11), with death in 3 patients. Median interval between last GO dose and HSCT was 130 days. Overall survival (OS) and SOS incidence did not differ for patients receiving GO ⩽3.5 months before HSCT and the others. CI of acute and chronic GVHD was 31% and 25%, respectively. Probability of OS and leukemia-free survival (LFS) at 5 years was 40% and 37%, respectively. Relapse incidence and non-relapse mortality were 42% and 21%, respectively. In multivariate analysis, active disease at HSCT was associated with relapse and worse LFS and OS (P<0.03). Liver abnormalities before HSCT correlated with worse OS (P<0.03). Use of low-dose GO prior to HSCT is associated with an acceptable SOS incidence. Prospective studies investigating the role and the utility of SOS prophylaxis are warranted.