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Gilteritinib is a potent and selective FLT3 kinase inhibitor with single-agent clinical efficacy in relapsed/refractory FLT3-mutated acute myeloid leukemia (AML). In this context, however, gilteritinib is not curative, and response duration is limited by the development of secondary resistance. To evaluate resistance mechanisms, we analyzed baseline and progression samples from patients treated on clinical trials of gilteritinib. Targeted next-generation sequencing at the time of AML progression on gilteritinib identified treatment-emergent mutations that activate RAS/MAPK pathway signaling, most commonly in NRAS or KRAS. Less frequently, secondary FLT3-F691L gatekeeper mutations or BCR–ABL1 fusions were identified at progression. Single-cell targeted DNA sequencing revealed diverse patterns of clonal selection and evolution in response to FLT3 inhibition, including the emergence of RAS mutations in FLT3-mutated subclones, the expansion of alternative wild-type FLT3 subclones, or both patterns simultaneously. These data illustrate dynamic and complex changes in clonal architecture underlying response and resistance to mutation-selective tyrosine kinase inhibitor therapy in AML.Significance:Comprehensive serial genotyping of AML specimens from patients treated with the selective FLT3 inhibitor gilteritinib demonstrates that complex, heterogeneous patterns of clonal selection and evolution mediate clinical resistance to tyrosine kinase inhibition in FLT3-mutated AML. Our data support the development of combinatorial targeted therapeutic approaches for advanced AML.See related commentary by Wei and Roberts, p. 998.This article is highlighted in the In This Issue feature, p. 983

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Purpose:Posttransplant cyclophosphamide (PTCy) is increasingly being utilized as a principle GvHD prophylaxis strategy in allogeneic hematopoietic cell transplantation (allo-HCT). A haploidentical (haplo) or matched unrelated donor (UD) is a valid option in the absence of a matched related donor.Experimental Design:We compared the outcomes of patients with acute leukemia who underwent haplo bone marrow (haplo-BM, N = 401) versus UD mobilized peripheral blood stem cells (UD-PB, N = 192) transplantation in the setting of PTCy.Results:The median follow-up duration was 36 months in the haplo-BM group and 16.6 months in the UD-PB group, respectively (P < 0.01). Myeloablative conditioning was used in 64.6% and 42.7% of haplo-BM and UD-PB patients, respectively (P < 0.01). Cumulative incidence of neutrophil engraftment at day 30 was 87% in haplo-BM versus 94% in UD-PB, respectively (P = 0.21). In the multivariate analysis, the risk of grade 2–4 acute GvHD (HR = 0.53, P = 0.01) and chronic GvHD (HR = 0.50, P = 0.02) was significantly lower in the haplo-BM group compared with the UD-PB group. There was no significant difference between the study groups with respect to relapse incidence, nonrelapse mortality, leukemia-fee survival, overall survival, or GvHD-free and relapse-free survival.Conclusions:The use of a haplo donor with a BM graft resulted in a lower incidence of GvHD compared with a UD-PB stem cell graft in the setting of PTCy for patients with acute leukemia. However, differences in GvHD did not translate into a difference in survival outcomes. Based upon these data, UD-PB or haplo-BM should be considered equally acceptable sources for allo-HCT.

Supplementary Data

Early mortality remains a challenging therapeutic facet of the initial induction phase of intensive chemotherapy in patients with acute myeloid leukemia (AML). The impact of standard molecular evaluation and risk category of the European LeukemiaNet (ELN) 2017 classification model on early mortality has not been rigorously evaluated thus far. We reviewed the medical records of 320 consecutive adult patients with newly diagnosed AML treated with intensive induction chemotherapy in our center from 2007 to 2021. The median age was 56 years; 33 patients (10%) died during induction. Patient age, white blood cell count, hemoglobin level, platelet level, creatinine, uric acid, lactate dehydrogenase serum levels, and FLT3-ITD and CEBPA mutational status did not significantly impact early mortality. NPM1

Second allogeneic hematopoietic stem-cell transplantation (HSCT2) is a therapeutic option for patients with AML/ MDS relapsing after a first transplant (HSCT1). However, patients allocated to HSCT2 may be a selected group with better prognosis and the added efficacy of HSCT2 is not well established. We retrospectively analyzed 407 consecutive patients with relapsed AML/MDS after HSCT1. Sixty-two patients had HSCT2 (15%) and 345 did not. The 2-year cumulative incidence rates of non-relapse mortality and relapse after HSCT2 were 26% (95% CI, 17-39%) and 50% (95% CI, 39-65%), respectively. The 5-year overall survival (OS) rates were 25% (95% CI, 14-36%) and 7% (95% CI, 4-10%) in the HSCT2 and no-HSCT2 groups, respectively. Multivariate-analysis identified female gender (HR 0.31, P=0.001), short remission duration after HSCT1 (HR 2.31, P=0.05), acute GVHD after HSCT1 (HR 2.27, P=0.035), HSCT2 from haplo-identical (HR 13.4, P=0.001) or matched-unrelated donor (HR 4.53, P=0.007) and relapse after HSCT1 in earlier years (HR 2.46, P=0.02) as factors predicting OS after HSCT2. Multivariate-analysis of all patients including HSCT2 entered as time-dependent variable identified relapse within 6 months after HSCT1 (HR 2.32, P

Define clinical and laboratory attributes of acute myeloid leukemia (AML) patients with long-term survival exceeding five years and compare them with AML patients succumbing to disease within 2 years of diagnosis.A retrospective analysis of AML patients alive at least five years from the time of initial diagnosis. Baseline clinical data were compared with patients who died within 2 years of diagnosis.The long-term cohort consisted of 93 patients treated in 2007-2016 with a median follow-up duration of 7.7 years (range 5-13.6 years). European LeukemiaNet (ELN) 2017 favorable risk patients accounted for 60% of the cohort. All long-term survivors achieved remission following induction chemotherapy. Multivariate analysis showed that compared with 132 patients experiencing death within 2 years of diagnosis, long-term survivors were more likely to be of younger age [odds ratio (OR), 0.92; 95% confidence interval (CI), 0.9-0.95; p 0.001], have a lower initial WBC count (OR, 0.58; 95% CI, 0.43-0.79; p = 0.0004), undergo an allogeneic stem cell transplantation (OR, 7.95; 95% CI, 3.07-20.59; p 0.0001), and harbor favorable risk cytogenetics (OR, 0.03; 95% CI, 0.006-0.23; p = 0.0004).Long-term survival of AML is seen in a distinct demographic and biologic patient subset.

Introduction: Blood product transfusion retains a critical role in the supportive care of patients with acute myeloid leukemia (AML). Whereas previous studies have shown increased transfusion dependency to portend inferior outcome, predictive factors of an increased transfusion burden and the prognostic impact of transfusion support have not been assessed recently. Methods/Patients: We performed a retrospective analysis on a recent cohort of patients given intensive induction chemotherapy in 2014–2022. Results: The analysis comprised 180 patients with a median age of 57 years with 80% designated as de novo AML. Fifty-four patients (31%) were FLT3-ITD mutated, and 73 patients (42%) harbored NPM1. Favorable risk and intermediate risk ELN 2017 patients accounted for 43% and 34% of patients, respectively. The median number of red blood cell (RBC) and platelet units given during induction were 9 and 7 units, respectively. Seventeen patients (9%) received cryoprecipitate, and fresh frozen plasma (FFP) was given to 12 patients (7%). Lower initial hemoglobin and platelet levels were predictive of increased use of RBC (p < 0.0001) and platelet transfusions (p < 0.0001). FFP was significantly associated with induction related mortality (42% vs. 5%; p < 0.0001) and with FLT3-ITD (72% vs. 28%; p = 0.004). Blood group AB experienced improved mean overall survival compared to blood group O patients (4.1 years vs. 2.8 years; p = 0.025). In multivariate analysis, increased number of FFP (hazard ratio [HR], 4.23; 95% confidence interval [CI], 2.1–8.6; p < 0.001) and RBC units (HR, 1.8; 95% CI, 1.2–2.8; p = 0.008) given was associated with inferior survival. Conclusion: Transfusion needs during induction crucially impact the clinical trajectory of AML patients.

Background The use of haploidentical hematopoietic cell transplantation (haplo-HCT) with posttransplantation cyclophosphamide prophylaxis is gaining traction in patients with acute lymphoblastic leukemia (ALL). Methods The Acute Leukemia Working Party/European Society for Blood and Marrow Transplantation registry was used to evaluate the outcomes of adult patients with ALL who underwent haplo-HCT during 2011 through 2015 and compared them with the outcomes of those who underwent transplantation during 2016 through 2018. Results The analysis consisted of 195 patients, including 79 who underwent transplantation during 2011 through 2015 and 116 who underwent transplantation during 2016 through 2018. Overall, the 2-year leukemia-free survival and relapse incidence rates were 56.5% and 21%, respectively. The 100-day incidence of grade 2 through 4 acute graft-vs-host disease (GVHD) was 34.5%. The rates of nonrelapse mortality (NRM) and overall survival (OS) were 22.5% and 64.7%, respectively. Patients who underwent transplantation during 2016 through 2018 experienced improved rates of leukemia-free survival (64.9% vs 47.3%; P = .019) and OS (75.5% vs 53.5%; P = .006). Patients who underwent transplantation during 2016 through 2018 developed more grade 2 through 4 acute GVHD (42% vs 26.4%; P = .047). The incidence of relapse, GVHD-free/relapse-free survival, grade 3 and 4 acute GVHD, chronic GVHD, and extensive chronic GVHD did not differ significantly between groups. In multivariate analysis, more recently transplanted patients had a significantly reduced risk of NRM (hazard ratio, 0.44; 95% CI, 0.22-0.89; P = .022) and improved OS (hazard ratio, 0.47; 95% CI, 0.26-0.86; P = .014). A comparable analysis of patients who had acute myeloid leukemia during the same timeframes did not reveal any statistically significant differences in any outcomes. Conclusions The outcome of adult patients with ALL who receive posttransplant cyclophosphamide has improved over time, with an impressive 2-year OS of 75% and, most recently, an NRM rate of only 17%.

Introduction: Achievement of an initial complete remission (CR) following induction chemotherapy is tightly correlated with survival in acute myeloid leukemia (AML) patients, yet patients in CR with incomplete hematologic recovery (CRi) still experience improved outcomes compared with nonresponding patients. Whether CRi predicts prognosis in patients referred to an allogeneic stem cell transplantation (allo-SCT) is incompletely defined. In this analysis, we evaluated whether clinical outcomes of transplanted AML patients in CR and CRi were significantly different. Methods: A retrospective single-center analysis of all de novo AML patients who underwent an allo-SCT between 2001 and 2015. The cohort included all adult patients with AML who underwent a first allo-SCT either in first or second CR or CRi at the time of transplantation. Results: The study cohort included 186 CR patients and 44 CRi patients. In univariate analysis, CRi was associated with inferior 3-year survival and 3-year nonrelapse mortality (NRM) compared to CR (41 vs. 62%; p = 0.022 and 27 vs. 10%; p = 0.006, respectively). In multivariate analysis, CRi was associated with decreased rates of survival (hazard ratio [HR] 2.01; 95% CI, 1.24–3.25; p = 0.005) and NRM (HR, 3.5; 95% CI, 1.6–7.8; p = 0.002). Conclusion: CRi in transplanted AML patients is potentially a potent predictor of increased NRM and survival.

Patients with FLT3-mutated relapsed or refractory (R/R) acute myeloid leukemia (AML) have a dismal prognosis. Gilteritinib is a FLT3 tyrosine kinase inhibitor (TKI) recently approved for patients with R/R AML. We aimed to characterize real-world data regarding gilteritinib treatment in FLT3-mutated R/R AML and to compare outcomes with matched FLT3-mutated R/R AML patients treated with chemotherapy-based salvage regimens. Twenty-five patients from six academic centers were treated with gilteritinib for FLT3-mutated R/R AML. Eighty percent were treated with a prior intensive induction regimen and 40% of them received prior TKI therapy. Twelve patients (48%) achieved complete response (CR) with gilteritinib. The estimated median overall survival (OS) of the entire cohort was eight (CI 95% 0-16.2) months and was significantly higher in patients who achieved CR compared to those who did not (16.3 months, CI 95% 0-36.2 vs. 2.6 months, CI 95% 1.47-3.7; p value = 0.046). In a multivariate cox regression analysis, achievement of CR was the only predictor for longer OS (HR 0.33 95% CI 0.11-0.97, p = 0.044). Prior TKI exposure did not affect OS but was associated with better event-free survival (HR 0.15 95% CI 0.03-0.71, p = 0.016). An age and ELN-risk matched comparison between patients treated with gilteritinib and intensive salvage revealed similar response rates (50% in both groups); median OS was 9.6 months (CI 95% 2.3-16.8) vs. 7 months (CI 95% 5.1-8.9) in gilteritinib and matched controls, respectively (p = 0.869). In conclusion, in the real-world setting, gilteritinib is effective, including in heavily pre-treated, TKI exposed patients.

There are no data indicating whether the number of induction courses needed to achieve first complete remission (CR1) is of prognostic significance in Haploidentical transplantation (HaploSCT). We compared transplantation outcomes of adults with AML that underwent HaploSCT in CR1, achieved following one or two induction courses. A total of 635 patients were included: 469 (74%) with 1 and 166 (26%) with two induction chemotherapy courses. A total of 429 (91.5%) and 151 (91%) patients had de novo AML and 40 (8.5%) and 15 (9%) had secondary AML (p = 0.84). Engraftment rates were 97.2 and 97.6%. Day 180 incidence of acute GVHD II-IV and III-IV was similar in both induction groups (31.1 and 34.8%, and 10 and 10.6 %), as was 2-4 year total and extensive chronic GVHD (33.7 and 36.5 %, and 12.2 and 12.1%), respectively. Two-year relapse incidence (RI) was higher while leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were inferior for patients achieving CR1 with 2 vs 1 course and were 29.1% vs 15.1%, 88 (p = 0.001), 56.2% vs 66.9% (p = 0.03), 58.8% vs 72.2% (p = 0.044) and 44% vs 55.6% (p = 0.013), respectively. Non-relapse mortality (NRM) did not differ, 18% vs 14.6% 90 (p = 0.25). These results were confirmed by multivariate analysis.

Baseline cytogenetics and disease status are key factors predicting the outcomes of allogeneic hematopoietic cell transplantation (HCT) in patients with acute myeloid leukemia (AML). The importance of cytogenetic risk in patients with primary refractory or relapsed (R/R) AML undergoing haploidentical (Haplo) HCT is unknown. We studied the impact of cytogenetic risk in patients with R/R de novo AML with active disease who underwent non-T-cell-depleted Haplo-HCT with post-transplantation cyclophosphamide from 2010 to 2020. Four hundred forty patients with active disease at transplantation from the European Society for Blood and Marrow Transplantation database were analyzed (291 [66.1%] with intermediate-risk [AMLint] and 149 [44.1%] with adverse-risk cytogenetics [AMLadv]). Impact of baseline cytogenetic risk on various transplantation outcomes was evaluated. Pre-transplantation disease status was relapse in 48.1% and 26.8% and primary refractory in 51.9% and 73.2% of the patients with AMLint and AMLadv, respectively (P.0001). Two-year leukemia-free survival (LFS, 35.5% versus 15.5%, P = .001) and overall survival (OS, 39.2% versus 20.1%, P = .001) were better in AMLint versus AMLadv. In multivariate analysis, the relapse rate was significantly higher (hazard ratio [HR] = 2.17 [95% confidence interval {CI} 1.57-3.0]) and LFS (HR = 1.71 [95% CI, 1.31-2.22]) and OS (HR = 1.69 [95% CI, 1.29-2.22]), significantly lower for patients with AMLadv compared to AMLint, conditioning intensity did not affect leukemia relapse rate. Non-relapse mortality (HR = 1.1 [95% CI, 0.7-1.74]) and graft-versus-host disease-free, relapse-free survival (HR = 1.37 [95% CI, 1.06-1.77]) did not differ significantly between the risk groups. Disease status before transplant (primary refractory versus relapsed) or conditioning intensity did not impact main transplant outcomes. Baseline cytogenetic risk remains a key prognostic factor for patients with R/R AML with persistent disease before non-T-cell-depleted Haplo-HCT.

While evidence for measurable residual disease (MRD) is a harbinger of inferior outcome in acute myeloid leukemia (AML) patients referred for allogeneic stem cell transplantation (allo-SCT), the exact clinical trajectory of specific patient subsets in this clinical setting is undefined. Using a recently published prognostic cytogenetic model (Canaani et al. Leukemia 2019) we evaluated whether this model applied also to studies of patients with positive MRD. The analysis comprised MRD+ patients in first complete remission undergoing allo-SCT from a matched sibling donor or unrelated donor. Seven hundred and seventy-five patients were evaluated with a median follow-up duration of 22 months. Cytogenetic risk score was favorable, intermediate/FLT3wt intermediate/FLT3-ITD3, and adverse in 15%, 28.3%, 37% and 19.7% of the patients, respectively. Favorable and intermediate/FLT3wt risk patients had 2-year leukemia-free survival rates of 78% and 61%, respectively, compared with only 50% and 37% for intermediate/FLT3-ITD3 and adverse risk patients, respectively (P < .001). In multivariate analysis adverse and intermediate/FLT3-ITD3 risk patients were more likely to experience disease relapse compared with favorable risk patients [hazard ratio (HR) = 3.9, 95% confidence interval (CI), 2.1-7.3; P < .001, and HR = 4.4, CI 95%, 2.4-7.8; P < .001, respectively]. The European society for blood and marrow transplantation cytogenetic risk score is a valuable adjunct for risk stratification of MRD+ AML patients.

A substantial segment of patients with acute myeloid leukemia (AML) will relapse following an initial response to induction therapy or will prove to be primary refractory. High-dose cytarabine and mitoxantrone (HiDAC/MITO) is an established salvage therapy for these patients. We studied all adult patients with relapsed/refractory (R/R) AML who were treated with HiDAC/MITO in our center between the years 2008-2017. To determine whether responding patients harbored a unique molecular signature, we performed targeted next-generation sequencing (NGS) on a subset of patients. The study cohort consisted of 172 patients with a median age of 54 years (range 18–77). The composite complete remission rate was 58%; 11 patients (6%) died during salvage therapy. Median survival was 11.4 months with a 1-year survival rate of 48%. In multivariate analysis favorable risk cytogenetics [Odds ratio (OR)=0.34, confidence interval (CI) 95%, 0.17–0.68; P = 0.002], and de-novo AML (OR = 0.4, CI 95%, 0.16–0.98; P = 0.047) were independently associated with a favorable response. Patients who attained a complete remission had a median survival of 43.7 months compared with 5.2 months for refractory patients (p < 0.0001). Neither the FLT3-ITD and NPM1 mutational status nor the indication for salvage therapy significantly impacted on the response to HiDAC/MITO salvage. NGS analysis identified 20 different mutations across the myeloid gene spectrum with a distinct TP53 signature detected in non-responding patients. HiDAC/MITO is an effective salvage regimen in R/R AML, however patients with adverse cytogenetics or secondary disease may not benefit as much from this approach.

Reduced-intensity conditioning (RIC) allows for the use of allogeneic hematopoietic stem cell transplantation (HSCT) in older patients with acute myelogenous leukemia (AML). We compared outcomes between 713 patients age ≥70 years and 16,161 patients age 50 to 69 years who underwent HSCT between 2004 and 2014. A higher proportion of the older patients were male and had secondary AML, active disease, a peripheral blood stem cell graft, a matched unrelated donor, an RIC regimen, and a lower Karnofsky Performance Status (KPS) score (P.001). In multivariate analysis, the incidences of acute and chronic graft-versus-host disease and relapse were similar in the 2 age groups. Nonrelapse mortality at 2 years was 34% (95% confidence interval [CI], 31% to 38%) in patients age ≥70 years and 24% (95% CI, 25% to 32%) in those age 50 to 69 years (P.001). Survival at 2 years in the 2 groups was 38% (95% CI, 34% to 42%) and 50% (95% CI, 49% to 50%), respectively (P.001). In patients with active disease, the corresponding percentages were 35% (95% CI, 29% to 41%) in those age ≥70 years and 33% (95% CI, 31% to 34%) in those age70 years (P = .36). In patients age ≥70 years, a KPS score of ≥80% was associated with improved survival (hazard ratio, 1.53; 95% CI, 1.14 to 2.06; P = .003). In summary, patients age ≥70 years had worse outcomes, except for those with active AML.

FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutational status is a pivotal prognosticator in acute myeloid leukemia (AML) patients and significantly increases the risk of disease relapse. However, it remains unclear whether in FLT3-ITD patients referred for allogeneic stem cell transplantation (allo-SCT), baseline cytogenetics significantly impacts clinical outcome. Using the European Society of Blood and Marrow Transplantation registry, we performed a retrospective analysis of 1631 FLT3-ITD AML patients who underwent allo-SCT with the aim of determining the influence of cytogenetic risk category on patient outcomes. Median patient age was 49 years and median follow-up duration was 36 months. Two-year leukemia-free survival (LFS) and incidence of relapse were 54% and 31.6%, respectively. Non-relapse mortality was experienced by 14.4% with a 2-year overall survival (OS) of 60.1%. On multivariate analysis, LFS was significantly lower in patients with intermediate and adverse risk cytogenetics compared with those with favorable risk cytogenetics, (hazard ratio [HR] = 1.48, 95% confidence interval [CI], 1.06-2.06; p = .02), and (HR = 01.65, 95% CI, 1.13-2.40; p = .009), respectively. OS was significantly lower in patients with adverse risk cytogenetics compared with patients with favorable risk cytogenetics (HR = 1.74, 95% CI, 1.16-2.61; p = .008) with a trend toward lower OS in patients with intermediate risk cytogenetics compared to those with favorable risk cytogenetics (HR = 1.43, 95% CI, 1.00-2.05; p = .052). In addition, adverse risk patients and intermediate risk patients experienced higher relapse rates compared with favorable risk patients (HR = 1.83, 95% CI, 1.13-2.94; p = .013 and HR = 1.82, 95% CI, 1.19-2.77; p = .005). Overall, cytogenetic studies aid in refinement of risk stratification in transplanted FLT3-ITD AML patients.

Chemotherapy-based approaches still constitute an essential feature in the treatment paradigm of adult acute lymphoblastic leukemia (ALL). The German Multicenter Study Group (GMALL) is a well-established protocol for ALL. In this study, we assessed our recent experience with the GMALL 07/2003 protocol reviewing all adult ALL patients who were treated with GMALL in three major centers in Israel during 2007-2020. The analysis comprised 127 patients with a median age of 41 years (range 17-83). Sixty-two were B-ALL (49%), 20 (16%) patients were Philadelphia chromosome positive ALL, and 45 (35%) were T-ALL. The 2-year and 5-year overall survival rates were 71% and 57%, respectively. The 2-year relapse rate was 30% with 2-year and 5-year leukemia-free survival rates of 59% and 50%, respectively. Adolescents and young adults experienced significantly longer overall survival (84 months versus 51 months; p=0.047) as well as leukemia-free survival compared with older patients (66 months versus 54 months, p=0.003; hazard ratio=0.39, 95% confidence interval, 0.19-0.79; p=0.009). T-ALL patients had longer survival compared to B-ALL patients while survival was comparable among Philadelphia chromosome positive patients and Philadelphia chromosome negative patients. An increased number of cytogenetic clones at diagnosis were tightly associated with adverse prognosis (15-month survival for ≥2 clones versus 81 months for normal karyotype; p=0.003). Positive measurable residual disease studies following consolidation were predictive for increased risk of relapse (64% versus 22%; p=0.003) and shorter leukemia-free survival (11 months versus 42 months; p=0.0003). While GMALL is an effective adult regimen, a substantial patient segment still experiences relapse.

Achievement of initial remission remains the most important clinical factor predicting long term survival in acute myeloid leukemia (AML) patients treated with intensive chemotherapy. Yet, whether the patient subset in need of a second cycle of intensive induction chemotherapy to reach remission experiences inferior outcomes compared to patients reaching remission after a single cycle of therapy, remains uncertain.Retrospective analysis of 302 consecutive AML patients treated with intensive induction chemotherapy in our institution in 2007-2020.Median patient age was 55 years with a median follow-up duration of 23 months. In terms of European LeukemiaNet (ELN) 2017 classification, 122 patients (40%) were designated as favorable risk disease, 108 patients (36%) were intermediate risk, and 71 patients (24%) were adverse risk. A hundred and seventy-seven patients (60%) attained remission following initial chemotherapy while 58 patients (20%) required an additional cycle of intensive chemotherapy for remission. Patients requiring 2 cycles to reach remission were less likely to be NPM1 mutated (33% versus 51%; P=.025) or be in the ELN 2017 favorable risk category (25% versus 57%; P.001). In multivariate analysis achievement of remission following 2 cycles of intensive compared with a single cycle resulted in significantly inferior survival [hazard ratio (HR)=1.67, 95% CI, 1.07-2.59; P=.025] whereas leukemia-free survival was not significantly impacted (HR=1.26, 95% CI, 0.85-1.85) (P=.23). Relapse rates also did not differ to a significant degree between groups (45% versus 47%, P=.8).Attainment of an early remission significantly impacts long term survival in AML patients.

Key Points Gilteritinib induces 2 distinct marrow responses in FLT3-mutated AML: responses with and without differentiation. Ongoing clonal hematopoiesis is ubiquitous during gilteritinib therapy and may promote genetic evolution and drug resistance.

Baseline cytogenetic studies at diagnosis remain the single most important determinant of outcome in patients with acute myeloid leukemia (AML). However, the prognostic role of the complete gamut of cytogenetic aberrations in AML patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently undefined. In addition, their significance in conjunction with FLT3-ITD status has not been addressed thus far. Using the ALWP/EBMT registry we conducted a retrospective analysis to determine the clinical outcomes of AML patients undergoing allo-HSCT with respect to specific recurring cytogenetic abnormalities complemented with FLT3-ITD status. We analyzed a cohort consisting of 8558 adult AML patients who underwent allo-HSCT from either a matched sibling or a matched unrelated donor. Patients with inv(3)(q21q26)/t(3;3)(q21;q26), del(5q), monosomy 7, chromosome 17p abnormalities, t(10;11)(p11-14;q13-23), t(6;11)(q27;q23), as well as those patients with a monosomal or complex karyotype experienced significantly inferior leukemia-free survival (LFS) compared to patients with a normal karyotype. Trisomy 14, del(9q), and loss of chromosome X were associated with improved LFS rates. A novel prognostic model delineating 5 distinct groups incorporating cytogenetic complexity and FLT3-ITD status was constructed with significant prognostic implications. Our analysis supports the added prognostic significance of FLT3-ITD to baseline cytogenetics in patients undergoing allo-HSCT.

Acute leukemia is an aggressive blood malignancy with low survival rates. A high expression of stem-like programs in leukemias predicts poor prognosis and is assumed to act in an aberrant fashion in the phenotypically heterogeneous leukemia stem cell (LSC) population. A lack of suitable genome engineering tools that can isolate LSCs based on their stemness precludes their comprehensive examination and full characterization. We hypothesized that tagging endogenous stemness-regulatory regions could generate a genome reporter for the putative leukemia stemness-state. Our analysis revealed that the ERG + 85 enhancer region can serve as a marker for stemness-state and a fluorescent lentiviral reporter was developed that can accurately recapitulate the endogenous activity. Using our novel reporter, we revealed cellular heterogeneity in several leukemia cell lines and patient-derived samples. Alterations in reporter activity were associated with transcriptomic and functional changes that were closely related to the hematopoietic stem cell (HSC) identity. Notably, the differentiation potential was skewed towards the erythro-megakaryocytic lineage. Moreover, an ERG + 85High fraction of AML cells could regenerate the original cellular heterogeneity and was enriched for LSCs. RNA-seq analysis coupled with in silico drug-screen analysis identified 4HPR as an effective inhibitor of ERG + 85High leukemia growth. We propose that further utilization of our novel molecular tool will identify crucial determinants of LSCs, thus providing a rationale for their therapeutic targeting.

Purpose: Posttransplant cyclophosphamide (PTCy) is increasingly being utilized as a principle GvHD prophylaxis strategy in allogeneic hematopoietic cell transplantation (allo-HCT). A haploidentical (haplo) or matched unrelated donor (UD) is a valid option in the absence of a matched related donor. Experimental Design: We compared the outcomes of patients with acute leukemia who underwent haplo bone marrow (haplo-BM, N = 401) versus UD mobilized peripheral blood stem cells (UD-PB, N = 192) transplantation in the setting of PTCy. Results: The median follow-up duration was 36 months in the haplo-BM group and 16.6 months in the UD-PB group, respectively (P < 0.01). Myeloablative conditioning was used in 64.6% and 42.7% of haplo-BM and UD-PB patients, respectively (P < 0.01). Cumulative incidence of neutrophil engraftment at day 30 was 87% in haplo-BM versus 94% in UD-PB, respectively (P = 0.21). In the multivariate analysis, the risk of grade 2–4 acute GvHD (HR = 0.53, P = 0.01) and chronic GvHD (HR = 0.50, P = 0.02) was significantly lower in the haplo-BM group compared with the UD-PB group. There was no significant difference between the study groups with respect to relapse incidence, nonrelapse mortality, leukemia-fee survival, overall survival, or GvHD-free and relapse-free survival. Conclusions: The use of a haplo donor with a BM graft resulted in a lower incidence of GvHD compared with a UD-PB stem cell graft in the setting of PTCy for patients with acute leukemia. However, differences in GvHD did not translate into a difference in survival outcomes. Based upon these data, UD-PB or haplo-BM should be considered equally acceptable sources for allo-HCT.

Cyclosporine A (CSA) and methotrexate (MTX) is the standard graft-versus-host disease (GVHD) prophylaxis regimen for matched sibling donor (MSD) allogeneic hematopoietic cell transplantation (allo-HCT). Recently, post-transplantation cyclophosphamide (PTCy) has been shown to be effective in GVHD prevention. In this registry-based study, we compared outcomes of 118 patients treated with PTCy and 1202 patients with CSA/MTX who underwent MSD allo-HCT for acute myelogenous leukemia. In a matched-pair analysis, PTCy was associated with a higher incidence of relapse at 2 years compared with CSA/MTX (41.1% versus 21.3%; P = .039). The incidences of day +180 grade II-IV acute GVHD and 2-year chronic GVHD were comparable in the PTCy and CSA/MTX arms (25.2% versus 25.4% [P = .90] and 42.6% versus 42.6% [P = .84], respectively). Similarly, 2-year leukemia-free survival (LFS; 54.4% versus 74.32%; P = .052), overall survival (OS; 70.6% versus 79.7%; P = .15), and GVHD-free relapse-free survival (GRFS; 38.1% versus 52.5%; P = .49) were not statistically different in the 2 arms. Our data show that GVHD prophylaxis with PTCy is feasible, resulting in similar incidences of GVHD, GRFS, LFS, and OS as seen with conventional CSA/MTX in patients undergoing allo-HCT from an MSD. The higher rate of relapse observed with PTCy needs further evaluation in a prospective study. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Background Relapsed/refractory acute myeloid leukemia (R/R AML) remains a significant therapeutic challenge and while meaningful therapeutics gains have been achieved with the introduction of novel agents, clinical outcomes remain unsatisfactory. Anthracyclines constitute an essential component of induction chemotherapy for AML patients, however owing in part to the cardiotoxicity concerns, they are not broadly prescribed in R/R AML settings. Bisantrene, an anthracene with anthracycline-like activity, was shown in earlier studies to be an effective salvage therapy in R/R AML with no discernible cardiotoxicity. In this study, we assessed the clinical efficacy of bisantrene in a cohort of heavily pre-treated R/R AML patients. Aims To investigate the safety and efficacy of bisantrene in adult patients with R/R AML. Methods This phase 2, single center study (NCT03820908) enrolled adult R/R AML to receive bisantrene (250 mg/m2 daily for 7 days) which was administered via an intravenous infusion over 2 hours on days 1-7. Patient therapy was limited to one completed cycle of bisantrene including those who had achieved a partial response. Disease assessment included routine blood work and bone marrow studies which were performed at baseline and subsequently at blood count recovery or suspected disease progression. Next generation sequencing (NGS) was performed at baseline for all patients with adequate pre-study samples. Results In all, 10 patients were recruited to the study with a median of 3 lines of prior therapy including 7 patients who had relapsed following allogeneic stem cell transplantation. With regard to disease burden, three patients had an antecedent myeloid disorder while 4 patients had extramedullary disease at study recruitment. The most frequently reported grade ≥3 treatment attributed hematologic AE was thrombocytopenia whereas the most frequently reported grade ≥3 treatment attributed non-hematologic AE was mucositis. Of the ten patients, one (10%) achieved a complete remission and three patients achieved a partial remission resulting in an overall response rate of 40% with one patient being bridged to transplantation. NGS of patient samples identified a wide array of mutations associated with activated signaling, splicing, and epigenetic modification (table 1). Conclusion In conclusion, in the present study bisantrene induced clinical responses in 4 of 10 patients with R/R AML with acceptable toxicity. Given its marked activity in patients with leukemia cutis, chroromas and CNS disease, we speculate that bisantrene-based chemotherapy may have a significant applicability in patients with extramedullary disease. In view of the observed efficacy and low related toxicity, a follow-up study combining bisantrene with complementary anti-leukemic therapy is planned. Disclosures Canaani: Abbvie: Consultancy, Honoraria, Research Funding. Benjamini:Abbvie Inc: Consultancy, Research Funding. Avigdor:Takeda, Gilead, Pfizer: Consultancy, Honoraria; Janssen, BMS: Research Funding.

While evidence for measurable residual disease (MRD) is a harbinger of inferior outcome in acute myeloid leukemia (AML) patients referred for allogeneic stem cell transplantation (allo-SCT), the exact clinical trajectory of specific patient subsets in this clinical setting is undefined. Using a recently published prognostic cytogenetic model (Canaani et al. Leukemia 2019) we evaluated whether this model applied also to studies of patients with positive MRD. The analysis comprised MRD

Heparanase is an endo-β-glucuronidase that specifically cleaves the saccharide chains of heparan sulfate (HS) proteoglycans and releases HS-bound cytokines, chemokines, and bioactive growth-promoting factors. Heparanase plays an important role in the nucleus as part of an active chromatin complex. Our previous studies revealed that rs4693608 correlates with heparanase levels and increased risk of acute and extensive chronic graft vs. host disease (GVHD). Discrepancy between recipient and donor in this SNP significantly affected the risk of acute GVHD. In the present study, we analyzed the HPSE gene region, including rs4693608, and demonstrated that this region exhibits SNPs-dependent enhancer activity. Analysis of nuclear proteins from normal leukocytes revealed their binding to DNA probe of both alleles with higher affinity to allele G. All malignant cell lines and leukemia samples disclosed a shift of the main bands in comparison to normal leukocytes. At least five additional shifted bands were bound to allele A while allele G probe was bound to only one main DNA/protein complex. Additional SNPs rs4693083, rs4693084, and rs4693609 were found in strong linkage disequilibrium (LD) with rs11099592 (exon 7). Only rs4693084 affected protein binding to DNA in cell lines and leukemia samples. As a result of the short distance between rs4693608 and rs4693084, both SNPs may be included in a common DNA/protein complex. DNA pull-down assay revealed that heparanase is involved in self-regulation by negative feedback in rs4693608-dependent manner. During carcinogenesis, heparanase self-regulation is discontinued and the helicase-like transcription factor begins to regulate this enhancer region. Altogether, our study elucidates conceivable mechanism(s) by which rs4693608 SNP regulates HPSE gene expression and the associated disease outcome.

Relapse has become the leading cause of treatment failure after stem cell transplantation. Besides cellular therapies and novel agents, immunotherapeutic strategies have entered clinical practice in order to reduce or prevent relapse. Here, we summarize the presentations on checkpoint inhibitors, vaccination strategies, and novel antibody therapies, which were presented and discussed at the third International Workshop on Biology, Prevention, and Treatment of Relapse after Stem Cell Transplantation.

Background: Venetoclax-based combinations were recently approved to treat patients (pts) with acute myeloid leukemia (AML) ineligible for intensive chemotherapy. Limited prospective 'real-world' data is available on treatment patterns of venetoclax-based therapy in routine clinical practice. We investigated patterns of patient selection, efficacy, toxicity, patient related outcome and post-remission management in a nationwide multicenter prospective observational trial. Methods: Newly diagnosed pts with AML were enrolled at the time of venetoclax-based therapy initiation from 10 medical centers in Israel. Demographic, clinical and patient-related baseline characteristics were documented. Treatment patterns, safety and efficacy outcomes are reported. Results: Between August 12, 2019, and June 17, 2021(data cut) ,127 AML pts were enrolled to receive venetoclax based therapy. Baseline patient and disease characteristics are reported in Table 1. The main reasons for physician's choice of venetoclax-based therapy were age ≥75, comorbidities and ECOG ≥2 (patient related factors) in 76% of cases and adverse disease biology predicting poor response to intensive chemotherapy (disease related factors) in 24% of cases. Most pts started therapy in an inpatient setting, 82 (64.6%) with a median hospitalization duration of 14 days, while 44 pts (34.6%) started therapy as out pts. Pts received a median of 3.8 cycles of therapy (range 1-21). Most pts (97%) received venetoclax in combination with hypomethylating agents. The full dose of 400mg QD after a median ramp-up duration of 3 days was achieved in 88% of the pts. Dose interruptions and dose modifications during follow-up occurred in 59 (46%) and 30 (24%) of pts, respectively. To allow for adequate follow up for response assessment, efficacy analysis was limited to pts enrolled prior to December 31, 2020, and included 108 pts with a median follow-up of 8 months (range 1-20). As of data cut, 93 pts completed cycle 1 of therapy, 66 pts completed cycle 3 and 39 pts completed cycle 6. 29 pts (27%) are still active on treatment. Best composite complete remission [CCR = complete remission (CR) plus CR with incomplete count recovery (CRi)] was achieved in 62 (57%) pts. CCR rates were assessed in different pre-defined subgroups. Best CCR in pts selected for therapy based on disease-related and patient-related factors were 70% and 54% respectively. Best CCR in pts with AML arising from MPN and pts with other AML were 45% and 58% respectively. Estimated median overall survival (OS) of all pts was 9.6 months (range 7.4-10.6) (Figure 1). Achieving CCR was associated with a superior probability for survival. Estimated median OS was 13.6 months (range 10.6 - not reached) in pts achieving CCR and 4.2 months (range 1.2-10.3) in non-CCR (p Allogeneic transplantation following venetoclax based treatment was offered to 16 (26%) pts with a median age of 71 years (range 43-77). Last documented response prior to transplant was CR in 5 (32%) pts, CRi 9 (56%), MLFS 1 (6%) and PR in 1 (6%) patient. Among grade ≥3 AEs were febrile neutropenia in 28% and infections in 21% of pts. Clinical and laboratory tumor lysis syndrome (TLS) was documented in 2 and 4 pts, respectively. Antifungal prophylaxis was administered in 20% of pts and granulocyte colony-stimulating factor (GCSF) support was used in 17% of pts in response. Early death rate at 30 and 60 days were 7% and 13%, respectively. Conclusion: This prospective real-world analysis reveals unique patterns of patient selection and venetoclax treatment utilization in a medical system with wide access for this indication. Venetoclax-based therapies are effective and associated with manageable toxicity, including in AML patient populations that were excluded from previous registration trials with comparable CCR and early death rates. Factors associated with patient selection in the 'real-world' setting and immature follow up data most probably led to a shorter estimated median OS in this analysis as compared to controlled trials. The REVIVE study continues to expand and is expected to provide additional insights on treatment patterns, management as well as clinical and patient related outcomes. Figure 1 Figure 1. Disclosures Wolach: Janssen: Consultancy; Novartis: Consultancy; Amgen: Research Funding; Astellas: Consultancy; Abbvie: Consultancy, Honoraria, Research Funding; Neopharm: Consultancy. Levi: AbbVie: Consultancy, Research Funding. Lavie: AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Fees for lectures; BMS: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Other: Fees for lectures; Roche: Other: Fees for lectures; Novartis: Other: Fees for lectures. Tavor: AbbVie: Consultancy. Hellmann: AbbVie: Consultancy. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Zuckerman: Gilead Sciences: Honoraria, Speakers Bureau; Novartis: Honoraria; Janssen: Honoraria; Cellect Biotechnology: Honoraria; BioSight Ltd: Honoraria; AbbVie: Honoraria; Orgenesis Inc.: Honoraria. Stemer: AbbVie: Consultancy. Berelovich: AbbVie: Current Employment, Current equity holder in publicly-traded company. Ofek: AbbVie: Current Employment, Current equity holder in publicly-traded company. Frankel: AbbVie: Current Employment, Current equity holder in publicly-traded company. Grunspan: AbbVie: Current Employment, Other: May hold equity. Ofran: Medison Israel: Consultancy; Pfizer: Consultancy; Astellas: Consultancy; AbbVie: Consultancy; Janssen: Consultancy. Moshe: Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Astellas: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Lectures.

Background. Early mortality remains a challenging therapeutic facet of the initial induction phase of intensive chemotherapy in patients with acute myeloid leukemia (AML). The impact of standard molecular evaluation and risk category of the European LeukemiaNet (ELN) 2017 classification model on early mortality have not been rigorously evaluated thus far. Aim. Evaluate the impact of standard clinical, laboratory, cytogenetic, and molecular parameters on the likelihood of early death following induction chemotherapy in a cohort of uniformly treated AML patients receiving standard intensive induction chemotherapy. Methods. We reviewed the medical records of 320 consecutive adult patients with newly diagnosed AML treated with intensive induction chemotherapy in our center from 2007 to 2021. The Kaplan-Meier method was used to determine overall survival and the log-rank test was used to compare differences between groups. All tests were two-sided and a p-value < 0.05 was considered statistically significant. Results. From October 2007 to January 2021, 320 adult patients with AML were treated with standard anthracycline and cytarabine-based intensive induction chemotherapy . Median age was 56 years (range, 18 to 92); 33 patients (10%) died during induction. As outlined in table 1, patient age, white blood cell count, hemoglobin level, platelet level, creatinine, uric acid, lactate dehydrogenase serum levels, FLT3-ITD and CEBPA mutational status did not significantly impact on early mortality. NPM1 mut patients had a lower likelihood of early death compared to NPM1 wt (5% versus 13%; p=0.023) whereas patients with high-risk cytogenetic studies experienced higher rates of induction mortality compared with intermediate and favorable risk patients (20% versus 8% and 7%, respectively; p=0.049). Adverse risk ELN 2017 were significantly more likely to die during induction compared with intermediate and favorable risk patients (20% versus 10% and 4%, respectively; p=0.001). Patients treated in 2007-2011 experienced a significantly higher rate of induction death compared with patients in 2012-2021 (17% versus 8%; p=0.039). Multivariate analysis confirmed adverse ELN 2017 [odds ratio (OR), 6.7; 95% confidence interval (CI), 1.77-25.3; p=0.005) and treatment timeframe (OR, 0.36; 95% CI, 0.15-0.87; p=0.023) as pivotal predictors of early mortality. Conclusion. Our data underscore the tight association of the ELN 2017 risk model with early induction mortality in AML patients receiving intensive induction chemotherapy. With the introduction of novel agents as well as innovative regimens combining these agents, it is becoming clear that better prognostic tools are needed at the provider level to navigate the rapidly changing therapeutic landscape seen in current management of AML patients. Our findings further underpin the importance of integrated prognostication models and their profound implications on the immediate peri-induction setting in AML patients. Figure 1 Figure 1. Disclosures Avigdor: Gilead: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; BMS: Research Funding; Janssen: Research Funding; Takeda: Consultancy, Honoraria.

Background: Achievement of initial remission remains the most important clinical factor predicting long term survival in acute myeloid leukemia (AML) patients treated with intensive chemotherapy. Yet, whether the patient subset in need of a second cycle of intensive induction chemotherapy to reach remission experiences inferior outcomes compared to patients reaching remission after a single cycle of therapy, remains uncertain with previous publication showing diverging outcomes with respect to patient survival and the risk for disease relapse (Rowe et al. Cancer 2010; Othus et al. Leukemia 2016). In this analysis we aimed to readdress this important clinical question in a uniform cohort of recently treated patients. Patients and Methods: Retrospective analysis of 302 consecutive AML patients treated with intensive induction chemotherapy in our institution in 2007-2020. Univariate analyses were performed using T-Test for continuous variables, and Fisher's Exact test and Pearson's chi-squared for assessment of categorical variables. Overall survival was assessed using the Kaplan-Meier method, and the log-rank test was used to compare overall survival between groups. Multivariate analyses using logistic regression were performed using year of diagnosis, patient age, follow-up duration, patient gender, white blood cell (WBC) count at diagnosis, MRC cytogenetic risk category, FMS-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD) and nucleophosmin 1 (NPM1) status, and ELN 2017 risk category, as covariates. All tests were two-sided with the type I error rate set at 0.05 for the determination of factors associated with time-to-event outcomes. Results: Median patient age was 55 years with a median follow-up duration of 23 months. In terms of European LeukemiaNet (ELN) 2017 classification, 122 patients (40%) were designated as favorable risk disease, 108 patients (36%) were intermediate risk, and 71 patients (24%) were adverse risk. A hundred and seventy-seven patients (60%) attained remission following initial chemotherapy while 58 patients (20%) required an additional cycle of intensive chemotherapy for remission. Patients requiring two cycles to reach remission were less likely to be NPM1 mutated (33% versus 51%; p=0.025) or be in the ELN 2017 favorable risk category (25% versus 57%; p Conclusion: Our analysis reaffirms the indispensable clinical significance of attainment of an early remission following intensive induction chemotherapy for AML patients. The marked long term survival advantage conferred by an early remission speaks to the need to improve initial remission rates which with the recent introduction of novel targeted therapeutics seems to be an attainable goal. Figure 1 Figure 1. Disclosures Avigdor: Gilead: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; BMS: Research Funding; Janssen: Research Funding; Takeda: Consultancy, Honoraria.

Haploidentical hematopoietic cell transplantation (haplo-HCT) is being increasingly used in acute leukemia patients as an alternative transplant modality when matched sibling or matched unrelated donors are unavailable. As several potential haploidentical relative donors are typically available for a given patient, optimizing donor selection to improve clinical outcome is crucial. The impact of donor age and kinship on the outcome of acute leukemia patients is not clearly established in this setting. Using the multinational registry of the acute leukemia working party of the European society for blood and marrow transplantation we retrospective analyzed the clinical outcome of 1270 acute myeloid leukemia and acute lymphoblastic leukemia patients who underwent haplo-HCT between 2005 and 2015. Patients over the age of 40 were significantly affected by increasing donor age resulting in higher non-relapse mortality (NRM) [Hazard ratio (HR)=1.86, confidence interval (CI) 95%, 1.18-2.94; P = .007], inferior leukemia-free survival (LFS) (HR = 1.59, CI 95%, 1.13-2.24; P = .007), and overall survival (OS) (HR = 1.74, CI 95%, 1.22-2.47; P = .002) when donors were over the age of 40. Additionally, kinship was found to be prognostically significant as patients transplanted from children donors over the age of 35 experienced an increased rate of NRM (HR = 1.82, CI 95%, 1.13-2.9; P = .01), inferior LFS (HR = 1.5, CI 95%, 1.05-2.13; P = .03), and OS (HR = 1.5, CI 95%, 1.04-2.15; P = .03). For patients younger than 40 years, donor age and kinship were mostly not clinically impactful. Our data establish donor age and kinship as significant determinants of outcome following haplo-HCT for acute leukemia patients.

Hematopoietic stem cell transplantation (HSCT) is being increasingly explored as a treatment modality for older patients with acute lymphoblastic leukemia (ALL). Yet, concerns regarding the long term outcome of transplantation in older patients limit the wide spread applicability of this approach. In this analysis we set out to determine the outcome of ALL patients over the age of 60 who underwent reduced intensity HSCT. Herein, we present the experience of the acute leukemia working party (ALWP) of the EBMT in this age group. We analyzed a cohort of 142 patients transplanted in first remission with a median age of 62 (range 60–76 years) and a median follow-up period of 36 months post-transplant. At 3 years, overall survival (OS) and leukemia-free survival were 42% and 35%, respectively. Multivariate analyses identified cytomegalovirus (CMV) donor-recipient matching (CMV D+/R+) to be significantly associated with inferior OS. Patients transplanted from unrelated donors experienced increased grade II-IV acute graft versus host disease compared to those receiving grafts from matched related donors [Hazard ratio (HR) of 3.7, 95% confidence interval (CI), 1.75–7.8; p = 0.0005). Outcome was not impacted by Philadelphia chromosome status. A select subset of older ALL patients will benefit from extended survival and a disease free state following HSCT.