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Fibrosing chronic graft-versus-host disease (cGVHD) is a debilitating complication of allogeneic stem cell transplantation (alloSCT). A driver of fibrosis is the kynurenine (Kyn) pathway, and Kyn metabolism patterns and cytokines may influence cGVHD severity and manifestation (fibrosing versus gastrointestinal [GI] cGVHD). Using a liquid chromatography-tandem mass spectrometry approach on sera obtained from 425 patients with allografts, we identified high CXCL9, high indoleamine-2,3-dioxygenase (IDO) activity, and an activated Kyn pathway as common characteristics in all cGVHD subtypes. Specific Kyn metabolism patterns could be identified for non-severe cGVHD, severe GI cGVHD, and fibrosing cGVHD, respectively. Specifically, fibrosing cGVHD was associated with a distinct pathway shift toward anthranilic and kynurenic acid, correlating with reduced activity of the vitamin-B2-dependent kynurenine monooxygenase, low vitamin B6, and increased interleukin-18. The Kyn metabolite signature is a candidate biomarker for severe fibrosing cGVHD and provides a rationale for translational trials on prophylactic vitamin B2/B6 supplementation for cGVHD prevention., Competing Interests: The authors declare no competing interests., (© 2021 The Authors.)

Background: Chronic graft-versus-host disease (cGVHD) represents a double-edged sword. In its nonsevere form, cGVHD associates with better control of the malignant disease, thus highlighting graft-versus-leukemia effects. However, severe cGVHD leads to debilitating morbidity and increased nonrelapse mortality. The prediction of severe cGVHD, in particular at disease onset, is therefore of high importance for ensuing clinical decisions and overall success of allogeneic stem cell transplantations. CXC-chemokine ligand 9 (CXCL9) is an interferon-inducible chemokine of the CXC family and is increased in cGVHD. Endothelial activation and stress index (EASIX) was shown to predict death after acute graft-versus-host disease. We explored CXCL9 and EASIX as predictors of severe cGVHD., Methods: Sera and clinical data of 480 patients were available who survived at least 6 months following allogeneic stem cell transplantation without steroid-refractory acute graft-versus-host disease and without early relapse. CXCL9 and EASIX were measured on day +100 and onset of cGVHD., Results: Development of nonsevere cGVHD was significantly associated with improved overall survival (hazard ratio 0.53, P < 0.001). CXCL9 serum levels at the onset of cGVHD predicted the development of severe cGVHD later on (hazard ratio 1.33, P = 0.02). In contrast, EASIX at the onset of cGVHD was not associated with cGVHD severity but was a significant independent risk factor for overall mortality and nonrelapse mortality., Conclusions: CXCL9 levels at the onset of cGVHD can help to predict severe courses of the disease and have potential for optimizing tailored administration of immunosuppressive therapy.

This study evaluates the immunological effects in 21 patients with multiple myeloma (MM) following allogeneic stem cell transplantation with a non-myeloablative conditioning regimen. Patients were heavily pretreated, most of them having progressed despite one to three courses of high dose chemotherapy followed by autologous stem cell rescue. For patients conditioned with low dose total body irradiation and Fludarabine, development of full (100%) donor chimerism (FDC) within the first 3-4 months strongly depended on the number of T cells transplanted. This putative graft-versus-haematopoiesis effect, however, did not coincide with clinical response. Rather, 10 of 17 patients progressed although FDC in peripheral blood was achieved. In contrast, clinical graft-versus-host disease (GvHD) of grade III-IV was associated with disease remission. Four of six patients achieved complete remission (CR) and one patient achieved a partial remission (PR) in close temporal relation with their acute GvHD. Two of four patients in CR succumbed to the consequences of this side effect. One patient in PR progressed soon after successful treatment of the GvHD, one of two patients with a long-lasting CR developed chronic GvHD. Our observations suggest the existence of two distinct immune effects in MM following allogeneic transplantations with reduced conditioning regimen. First, the putative graft-versus-haematopoiesis effect that induced FDC was observed in all patients receiving unmanipulated grafts. Secondly, the graft-versus-myeloma effect that induced CR did not correlate with FDC but was associated with grade III-IV GvHD in our group of heavily pretreated patients.

Despite prophylaxis with immunosuppressive drugs, severe graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality following allogeneic stem cell transplantation. T cell depletion of the graft has decreased incidence and severity of GVHD but has resulted in a higher incidence of graft failure and relapse. To reduce the risk of severe GVHD, but at the same time to maintain the graft-versus-tumor effect, we administered a fixed low number of 1 x 10(5) donor T cells per kilogram of body weight to recipients of CD34(+) cell-enriched allogeneic peripheral blood stem cells (PBSCs). Donor lymphocyte infusions (DLI) were then given in incremental doses when mixed chimerism persisted or signs of relapse occurred. A total of 23 patients receiving allografts from related and unrelated donors were treated according to this protocol after myeloablative or reduced intensity conditioning. One patient did not engraft and 3/20 evaluable patients developed acute (a) GVHD > or = grade II, with a corresponding estimated cumulative incidence of 15.6% (95% CI 0-30.5%). DLI (n = 13) induced aGVHD > or = II in 6 patients, but the severity of the syndrome was reduced. Overall GVHD-related mortality was low (13%). The probability of disease-free survival and overall survival at 2 years was 0.40 (95% CI 0.21-0.75) and 0.36 (95% CI 0.21-0.63). Progression-free survival and overall survival was significantly better in patients with acute or chronic myelogenous leukemia compared to patients with lymphoproliferative disorders (p = 0.002; p = 0.02). We conclude that the combination of allografts with a T cell content of about 1 x 10(5)/kg and escalating doses of DLI is a viable transplant strategy in patients with myeloid leukemias, which results in stable engraftment and a reduction of mortality from aGVHD.

Physical capacity prior allogeneic stem cell transplantation (allo-HCT) has been shown as a relevant prognostic factor for survival after transplant. Therefore, we evaluated feasibility and preliminary efficacy of a high-intensity interval training (HIIT) and moderate to high-intensity resistance exercise (RE) to increase physical capacity in patient's prior allo-HCT. In this multicentre single arm pilot study, a supervised exercise program was performed twice weekly for 4–12 weeks prior allo-HCT, depending on the individual time remaining. Outcomes were feasibility (recruitment, adherence, safety), physical capacity (cardiorespiratory fitness [VO2peak], muscle strength) and patient reported outcomes (physical functioning, fatigue). Thirty patients were intended, 16 could be included, and 14 completed post intervention assessment (75% male, 55 ± 11 years). The study was stopped early due to a low recruitment rate. Nine patients (64%) reached the initial minimum planned number of eight exercise sessions. Individual adherence was high with 92% for HIIT and 85% for RE. 87% of all performed exercise sessions were completed without complaints and VO2peak increased significantly from 20.4 to 23.4 ml/kg/min. The low recruitment rate suggests that initiation of the intervention concept immediately before allo-HCT is feasible only in a small number of patients. In particular, the timeframe directly prior allo-HCT seems too short for exercise interventions, although the exercise program was designed to improve outcomes in a very short time frame. HIIT and RE were feasible, effective and well accepted by the included patients. [ABSTRACT FROM AUTHOR]

Patient numbers for EASIX calculation are listed in following order (no neutropenic fever or sepsis / neutropenic fever without sepsis/neutropenic fever with sepsis) for the different timepoints: prior conditioning n = 125/200/27, day-3 n = 85/159/23, day 0 n = 84/159/23, day 3 n = 86/157/23, day 5 n = 87/153/22, day 7 n = 89/157/22, day 14 n = 108/161/20, day 21 n = 119/185/21, day 28 n = 120/194/17. As numbers of patients with sepsis were still small, these results warrant confirmation in larger multicenter trials with more sepsis patients. Sepsis patients were subgrouped by no neutropenic fever or sepsis, and neutropenic fever without and with sepsis. [Extracted from the article]

Background: Allogeneic haematopoietic stem cell transplantation (alloSCT) often remains the only curative therapy for hematologic malignancies. Although the management of transplant‐associated adverse events considerably improved over the last decades, nonrelapse mortality (NRM) remains a challenge, and endothelial dysfunction was identified as a major contributor to NRM. Methods: Statin‐based endothelial prophylaxis (SEP) has been implemented in the standard of care in our transplant centre to reduce NRM caused by endothelial injury. Here, we retrospectively analysed the impact of SEP on clinical outcome in a cohort of 347 alloSCT patients. Results: SEP (n = 209) was associated with significantly reduced NRM (hazard ratio 0.61, 95% CI 0.38–0.96) and better overall survival (OS) after acute graft‐versus‐host disease (HR 0.59, 95% CI 0.37–0.93). Subgroup analyses showed that the NRM benefit was mainly found in patients with an intermediate endothelial activation and stress index (EASIX), while relapse risk was not affected. On day 100 post‐alloSCT, patients receiving SEP had significantly higher levels of the rate‐limiting enzyme of tryptophan metabolism, indoleamine 2,3‐dioxygenase (IDO), higher kynurenine to tryptophan ratios as a proxy of IDO activity and tended to have lower levels of the endothelial injury marker ST2 (p =.055). No significant differences in interferon‐gamma or IL18 levels were observed. These biomarker signatures suggest that the beneficial effects of SEP might be mediated by both endothelial protection and immunomodulation. Conclusions: Together, these data suggest that SEP improves NRM and OS post‐alloSCT in particular in patients with intermediate endothelial risk and provide first mechanistic clues about its potential mode of action. [ABSTRACT FROM AUTHOR]

Finally, other potential treatment options to reduce relapse/progression post alloSCT include post-transplantation cyclophosphamide (ptCy). Keywords: myeloma therapy; stem cell transplantation; cytogenetics EN myeloma therapy stem cell transplantation cytogenetics 244 248 5 12/27/21 20220101 NES 220101 Treatment of patients with relapsed multiple myeloma (MM) after autologous stem cell transplantation (autoSCT) remains challenging. Consequently, a future goal in MM therapy is to combine modern treatment concepts and alloSCT in suitable patients to reduce disease burden and enhance disease control in patients with relapsed high-risk MM. Details on re-induction treatment and response rates prior to alloSCT, engraftment and post alloSCT response rates, maintenance therapy, donor lymphocyte infusions (DLI) and relapse therapies are shown in Table I. The median age at alloSCT was 50 (range 34-64) years. [Extracted from the article]

Background: The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and has evoked a pandemic that challenges public health-care systems worldwide. Endothelial cell dysfunction plays a key role in pathophysiology, and simple prognosticators may help to optimize allocation of limited resources. Endothelial activation and stress index (EASIX) is a validated predictor of endothelial complications and outcome after allogeneic stem cell transplantation. Aim of this study was to test if EASIX could predict life-threatening complications in patients with COVID-19. Methods: SARS-CoV-2-positive, hospitalized patients were enrolled onto a prospective non-interventional register study (n=100). Biomarkers were assessed at hospital admission. Primary endpoint was severe course of disease (mechanical ventilation and/or death, V/D). Results were validated in 126 patients treated in two independent institutions. Results: EASIX at admission was a strong predictor of severe course of the disease (odds ratio for a two-fold change 3.4, 95%CI 1.8-6.3, p<0.001), time to V/D (hazard ratio (HR) for a two-fold change 2.0, 95%CI 1.5-2.6, p<0.001) as well as survival (HR for a two-fold change 1.7, 95%CI 1.2-2.5, p=0.006). The effect was retained in multivariable analysis adjusting for age, gender, and comorbidities and could be validated in the independent cohort. At hospital admission EASIX correlated with increased suppressor of tumorigenicity-2, soluble thrombomodulin, angiopoietin-2, CXCL8, CXCL9 and interleukin-18, but not interferon-alpha. Conclusion: EASIX is a validated predictor of COVID19 outcome and an easy-to-access tool to segregate patients in need for intensive surveillance. [ABSTRACT FROM AUTHOR]

Purpose: Cardiorespiratory fitness (CRF) seems to be prognostic prior to allogeneic stem cell transplantation (allo-HSCT). Influencing factors of CRF in allo-HSCT candidates have not been studied so far. Aim was to identify potentially influencing factors on CRF. Methods: To assess CRF, a maximal cardiopulmonary exercise test (CPET) was performed on average 2.6 ± 7.2 days prior to admission. A regression analysis was conducted, with the following predictors: gender, age, body mass index (BMI), time between last therapy and allo-HSCT (t_Therapies), number of cardiotoxic therapies (n_Cardiotox), number of transplantations (n_Transplantations), comorbidity index (HCT-CI), hemoglobin level of the last 3 months (area under the curve), and physical activity. Results: A total of 194 patients performed a CPET. VO2peak was significantly reduced compared with reference data. In total, VO2peak was 21.4 ml/min/kg (− 27.5%, p < 0.05). Men showed a significant larger percentage difference from reference value (− 29.1%, p < 0.05) than women (− 24.4%). VO2peak was significantly (p < 0.05) influenced by age (β = − 0.11), female gender (β = − 3.01), BMI (β = − 0.44), n_Cardiotox (β = − 0.73), hemoglobin level (β = 0.56), and physical activity prior to diagnosis (β = 0.10). Conclusions: Our study demonstrates a decreased CRF indicating the potential need of prehabilitative exercise. We revealed some influencing factors on CRF. Those patients could benefit the most from exercise. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To improve monitoring of myeloid neoplasms by flow cytometry‐based minimal residual disease (MRD) analysis, we analyzed the significance of leukemia‐associated immunophenotype (LAIP) markers in 44 patients. Methods: In a pilot study cohort, peripheral blood or bone marrow samples from 13 patients with myeloid neoplasms and one case of B lymphoblastic leukemia in complete hematologic remission after allogeneic bone marrow or stem cell transplantation were subjected to selection for leukemia‐specific phenotypes by fluorescence‐activated cell sorting using individual marker combinations, followed by PCR‐based chimerism analysis. Results: The feasibility of this method could be demonstrated, with selection being successful in 12 cases, including two cases where mixed chimerism was found exclusively in sorted cells. Interestingly, four specimens displayed full donor chimerism in cells expressing the presumably aberrant combination CD34+/CD7+. Further analyses, including assessment of an independent cohort of 25 patients not affected by neoplastic bone marrow infiltration, revealed that normal myeloid precursors usually include a population coexpressing CD34, CD13, CD33, and CD7. Conclusion: We conclude that the combination CD34+/CD7+ might not be suitable as an LAIP for MRD diagnostics and that a subset of normal myeloid precursors in the bone marrow expresses CD7. [ABSTRACT FROM AUTHOR]

The role of autologous stem cell transplantation (autoSCT) as consolidating treatment for peripheral T-cell lymphoma (PTCL) is unsettled. The aim of this analysis was to investigate the impact of autoSCT in the upfront setting by intent-to-treat and to study salvage strategies after relapse. Retrospective follow-up of all patients aged 18-70 years and treated at our institution for ALK-PTCL diagnosed between 2001 and 2014. Of 117 eligible patients, diagnosis was PTCL-NOS in 34, ALCL ALK- in 31, AITL in 28, and other PTCL in 24 patients. Disregarding 20 patients who received first-line treatment externally, upfront autoSCT was not intended in 34 due to comorbidity, higher age, low IPI, physician's decision or unknown reasons (nITT), while intent-to-transplant (ITT) was documented in 63 patients. ITT was not associated with significant benefits for 5-year progression-free survival (PFS) and overall survival (OS) with 46 and 23% in the ITT group vs. 42 and 25% in the nITT group, even after multivariate adjustment for confounders. Altogether, 91 of all 117 patients relapsed or progressed. Thirty-one patients managed to proceed to salvage allografting and achieved a 5-year OS of 52%. In contrast, all 7 patients receiving salvage autoSCT relapsed and died, and only 3 of the 51 patients not eligible for SCT salvage survived. In this study, a significant benefit of intending first-line autoSCT over non-transplant induction in patients with ALK-PTCL did not emerge. Most patients fail first-line treatment and have a poor outlook if salvage alloSCT cannot be performed. [ABSTRACT FROM AUTHOR]

Purpose: The prognosis of patients with advanced-phase chronic myeloid leukemia (CML) remains dismal despite the availability of targeted therapies and allogeneic stem cell transplantation (allo-SCT). Increasing the antileukemic efficacy of the pretransplant conditioning regimen may be a strategy to increase remission rates and duration. We therefore investigated the antiproliferative effects of nilotinib in combination with drugs that are usually used for conditioning: the alkylating agents mafosfamide, treosulfan, and busulfan. Methods: Drug combinations were tested in vitro in different imatinib-sensitive and imatinib-resistant BCR-ABL-positive cell lines. A tetrazolium-based MTT assay was used for the assessment and quantification of growth inhibition after exposure to alkylating agents alone or to combinations with nilotinib. Drug interaction was analyzed using the median-effect method of Chou and Talalay, and combination index (CI) values were calculated according to the classic isobologram equation. Results: Treatment of imatinib-sensitive, BCR-ABL-positive K562 and LAMA84 cells with nilotinib in combination with mafosfamide, treosulfan, or busulfan resulted in synergistic (CI < 1), additive (CI ~ 1), and predominantly antagonistic (CI > 1) effects, respectively. In imatinib-resistant K562-R and LAMA84-R cells, all applied drug combinations were synergistic (CI < 1) at higher growth inhibition levels. Conclusions: Our in vitro data warrant further investigation and may provide the basis for nilotinib-supplemented conditioning regimens for allo-SCT in advanced-phase CML. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses the prospective studies on the effect of pretransplant imatinib in patients with blast crisis of chronic myeloid leukemia (BC-CML) after myeloablative allogeneic stem cell transplantation (allo-SCT).

Weight loss and metabolic activity influence outcome after allogeneic stem cell transplantation (alloSCT). This study evaluates pre-conditioning Leptin, a peptide hormone involved in metabolism and immune homeostasis, as a prognostic factor for survival, relapse and non-relapse mortality (NRM) following alloSCT. Leptin serum levels prior to conditioning were determined in a cohort of patients transplanted for various hematologic malignancies (n = 524) and correlated retrospectively with clinical outcome. Findings related to patients with acute leukemia (AL) from this sample were validated in an independent cohort. Low pre-conditioning serum Leptin was an independent prognostic marker for increased risk of relapse (but not of NRM and overall mortality) following alloSCT for AL of intermediate and advanced stage (beyond first complete remission). Multivariate analysis revealed a hazard ratio (HR) for relapse of 0.75 per log2 increase (0.59–0.96, p = 0.020). This effect was similar in an independent validation cohort. Pre-conditioning serum Leptin was validated as a prognostic marker for early relapse by fitting the multivariate Cox model to the validation data. Pre-conditioning serum Leptin levels may serve as an independent prognostic marker for relapse following alloSCT in intermediate and advanced stage AL patients. Prospective studies are required to prove whether serum Leptin could be used for guiding nutritional intervention in patients with AL undergoing alloSCT. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic threatens patients with a compromised immune and endothelial system, including patients who underwent allogeneic stem cell transplantation (alloSCT). Thus, there is an unmet need for optimizing vaccination management in this high-risk cohort. Here, we monitored antibodies against SARS-CoV-2 spike protein (anti-S1) in 167 vaccinated alloSCT patients. Humoral immune responses were detectable in 81% of patients after two vaccinations with either mRNA-, vector-based, or heterologous regimens. Age, B-cell counts, time interval from vaccination, and the type of vaccine determined antibody titres in patients without systemic immunosuppression (sIS). Similar to a healthy control cohort, mRNA vaccine-based regimens induced higher titres than vector-based vaccines. Patients on two or more immunosuppressants rarely developed immunity. In contrast, 62% and 45% of patients without or on only one immunosuppressant, respectively, showed a strong humoral vaccination response (titre > 100). Exacerbation of cGVHD upon vaccination was observed in 6% of all patients and in 22% of patients receiving immunosuppression for cGVHD. cGVHD exacerbation and low antibody titres were both associated with higher angiopoietin-2 (ANG2) serum levels. In conclusion, mRNA-based vaccines elicit strong humoral responses in alloSCT patients in the absence of double sIS. Biomarkers such as ANG2 might help with weighing cGVHD risk versus beneficial responses. [ABSTRACT FROM AUTHOR]

Acute graft-versus-host disease (GVHD) is a major complication of allogeneic stem cell transplantation (SCT) and can be readily controlled by systemic high-dose steroids in many patients. However, patients whose GVHD is refractory to this therapy have a poor prognosis. Refractory patients have ongoing end-organ damage despite effective immunosuppression with second-line regimens, suggesting pathomechanisms independent from the initiating T-cell attack. To explore whether endothelial damage might contribute to GVHD refractoriness and to study the role of angiopoietin-2 (ANG2) in this process, we have compared kinetics of T-cell activation markers and markers of endothelial dysfunction in the serum of patients with sensitive (n = 23) and refractory GVHD (n = 25). Longitudinal measurements of soluble FAS ligand along with other immune markers demonstrate that refractory patients are not exposed to an overwhelming or unresponsive T-cell attack. However, in contrast to sensitive GVHD, refractory GVHD was associated with rising thrombomodulin levels and high ANG2/ vascular endothelial-derived growth factor ratios. Patients with refractory GVHD showed significantly increased ANG2 levels already before SCT. These results suggest that endothelial cell vulnerability and dysfunction, rather than refractory T-cell activity, drives treatment refractoriness of GVHD and opens new avenues for prediction and control of this devastating condition. [ABSTRACT FROM AUTHOR]

The article presents the case of a 58-year-old patient with relapsed multiple myelomia and was diagnosed with visceral leishmaniasis. Topics include the possible causes of leishmaniasis including transfusion of blood products from healthy carriers, sandfly bite and reactivation of a sublinical/latent infection, and the link between the differential diagnosis of VL and patients with fever of unknown origin, obscure hepatosplenogmegaly and pancytopenia.

To expand the current knowledge about azacitidine (Aza) and donor lymphocyte infusions (DLI) as salvage therapy for relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and to identify predictors for response and survival, we retrospectively analyzed data of 154 patients with acute myeloid leukemia (AML, n = 124), myelodysplastic (MDS, n = 28), or myeloproliferative syndrome (n = 2). All patients received a median number of 4 courses of Aza (range, 4 to 14) and DLI were administered to 105 patients (68%; median number of DLI, 2; range, 1 to 7). Complete and partial remission rates were 27% and 6%, respectively, resulting in an overall response rate of 33%. Multivariate analysis identified molecular-only relapse (hazard ratio [HR], 9.4; 95% confidence interval [CI], 2.0 to 43.5; P = .004) and diagnosis of MDS (HR, 4.1; 95% CI, 1.4 to 12.2; P = .011) as predictors for complete remission. Overall survival (OS) at 2 years was 29% ± 4%. Molecular-only relapse (HR, .14; 95% CI, .03 to .59; P = .007), diagnosis of MDS (HR, .33; 95% CI, .16 to .67; P = .002), and bone marrow blasts <13% (HR, .54; 95% CI, .32 to .91; P = .021) were associated with better OS. Accordingly, 2-year OS rate was higher in MDS patients (66% ± 10%, P = .001) and correlated with disease burden in patients with AML. In summary, Aza and DLI is an effective and well-tolerated treatment option for patients with relapse after allo-HSCT, in particular those with MDS or AML and low disease burden. The latter finding emphasizes the importance of stringent disease monitoring and early intervention. [ABSTRACT FROM AUTHOR]

Allogeneic stem cell transplantation (SCT) is potentially curative therapy for patients with MDS. Prior studies have shown no overall-survival (OS) advantage of any conditioning regimen over the others. Reduced-intensity conditioning (RIC) is usually associated with lower non-relapse mortality (NRM) compared to myeloablative conditioning (MAC), however, relapse rates are higher, resulting in similar OS. Fludarabine and treosulfan (FT) is a reduced-toxicity regimen with intense anti leukemia activity in patients with myeloid malignancies. We explored outcomes following FT conditioning in comparison with other regimens. We retrospectively analyzed SCT outcomes of MDS patients reported to the chronic malignancies working party of EBMT (n=1722). The conditioning regimens were defined according to standard EBMT criteria and included FT (n=367), RIC (n=687) or MAC (n=668). FT and RIC recipients were older than MAC recipients, median age 59, 59 and 51 years, respectively (P < 0.001). More FT recipients had untreated MDS at SCT, 45%, 26% and 36%, respectively (P < 0.001). Disease status at diagnosis, cytogenetics, secondary origin and prior transformation to AML, were not different between the regimens. With a median follow-up of 20 months (1-171), 807 patients are alive, 328 died of relapse and 587 had NRM. The 5-year rates of relapse, NRM and OS for the entire group were 21% (95%CI, 19-23), 35% (95%CI, 33-38) and 44% (95%CI, 42-437), respectively. Relapse rates were similar after FT and MAC, 16% (13-21) and 19% (16-22), respectively, significantly lower than after RIC, 25% (21-28) (P = 0.003). Multivariate analysis (MVA) identified age >55 years (HR 1.42), advanced histology (RAEB 1/2, HR 2.01/ 1.73), prior transformation to AML (HR 1.87), refractory disease to prior therapies (HR 1.75) secondary origin (HR 1.33) and poor cytogenetics (HR 2.83) as associated with higher relapse risk. FT conditioning was associated with a lower risk (HR 0.63, P = 0.006). NRM was lower after FT and RIC than after MAC, 34% (29-39), 33% (30-37) and 38% (35-40), respectively (P = 0.05). MVA identified age >55 years (HR 1.39) and MAC (HR 1.34) as associated with higher NRM, while SCT from sibling donor (HR 0.81) and in CR (HR 0.80) were associated with a lower risk. In all, 5-year OS was 50% (44-55), 43% (38-47), and 43% (39-47), after FT, RIC and MAC, respectively (Figure 1, P = 0.03). MVA identified age >55 years (HR 1.39), advanced histology (RAEB 1/2, HR 1.35/ 1.10), prior transformation to AML (HR 1.37), and poor cytogenetics (HR 1.58) as associated with lower OS. FT conditioning was associated with better OS (HR 0.79, P = 0.01). FT is associated with similar low relapse rates as MAC and similar low NRM as RIC, resulting in improved outcome over both RIC and MAC. FT might be the preferred regimen for SCT in MDS. These observations merit further study in randomized prospective trials. [ABSTRACT FROM AUTHOR]