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Despite recent emergence of novel target agents, allogeneic stem cell transplantation is still the favored option for disease control in relapsed patients with acute myeloid leukemia (AML). Allotransplant from alternative donors such as haploidentical donor or cord blood can be done when fully HLA matched donor is not available. As for patients relapsed after the first stem cell transplantation (SCT1), these alternative stem cell sources often become only available options for the second transplantation. However, there has been no report comparing haploidentical stem cell (HIT) and cord blood transplantation (CBT), especially for the second transplantation. We performed a retrospective cohort study on AML patients who relapsed after SCT1 and underwent second allogeneic SCT from either alternative donor at our institution. We identified a total of 50 corresponding patients between January 2008 and February 2021 where 31 HIT and 19 CBT were included, and analyzed SCT outcomes including overall survival (OS), disease free survival (DFS), cumulative incidence of relapse (CIR), non-relapse mortality (NRM) and the incidence of SCT complications with comparing between the 2 groups. Conditioning regimens for HIT and for CBT were as follows: Fludarabine (30mg/m2/day intravenous (IV) for 5 days), busulfan (3.2mg/kg/day IV for 2 days), fractionated total body irradiation (fTBI, 4-8Gy total) and rabbit antithymoglobulin at a dose of 1.25mg/kg/day for four days for in vivo T cell depletion from D-5 to D-2 was given for HIT. G-CSF-mobilized peripheral blood stem cell was used as allograft. Graft-versus-host disease (GVHD) prophylaxis was done with tacrolimus and methotrexate. For CBT, fludarabine (30mg/m2/day IV for 5 days), cytarabine (1.5g/m2 twice daily for 3 days) with fTBI (12Gy). All CBT patients received double cord blood units. GVHD prophylaxis was done with tacrolimus and mycophenolate mofetil. The median follow-up period for survivors was 64.6 months (range 5.3-154.1). The type of SCT1 differed between the two groups; more patients of HIT were the recipient of prior autologous transplantation (41.9%), and 63.2% of CBT had underwent prior HIT (p Overall respective outcomes of HIT and CBT were as follows; 41% and 29% for 2-year OS (p=0.017), 41% and 16% for 2-year DFS (p=0.016), 36% and 36% for 2-year CIR (p=0.91) and 23% and 48% for 2-year NRM (p=0.021). Early NRM within 100 days of SCT2 was more frequent in CBT than HIT although not statistically significant (26.3% vs 9.7%, p=0.23). Median days to neutrophil and platelet engraftment were 12 (range 11-23) and 13 (range 9-38) in HIT, and 29 (range 16-48), 51 (range 27-167) for CBT, respectively (p This is the first report, to the best of our knowledge, to compare outcomes of the second transplantation from alternative donors for relapsed AML patients after SCT1. Our unique T-cell replete HIT using a reduced-toxicity conditioning regimen seems to provide better survival than CBT. Figure 1 Figure 1. Disclosures Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria.

Background Although European Leukemia Net (ELN) risk classification was introduced in 2017 and has been applied as an important prediction tool for prognosis, there has been limited data on its value among the patients with allogeneic hematopoietic stem cell transplantation (HSCT). We evaluated the prognostic value of ENL 2017 criteria on post-HSCT outcomes and compared it with pre-HSCT measurable residual disease (MRD) status determined by Wilms tumor gene 1 (WT1) expression level. Methods: Patients who underwent HSCT and fulfilled following criteria were eligible in this current study: first HSCT in complete remission (CR) or CR with incomplete hematologic recovery and having bone marrow WT1 expression results before transplant. We found a total of 275 patients between Nov 2017 and July 2020, and we adopted the WT1 cut-off level of 250 copies per 10 4 ABL for defining MRD negative vs positive (Biol Blood Marrow Transplant. 2019;25:1925) . Results: Among 180 patients, , 110 (61%) and 70 (39%) patients were classified as a , intermediated (INT) and adverse (ADV) risk group by ELN 2017 classification. After a median follow-up of 18.3 months (range, 0.4 to 43.2 months), the Kaplan-Meier survival curve could not discriminate overall survival (OS), relapse free survival (RFS), or cumulative incidence of relapse (CIR) between the INT and ADV risk groups (p=0.2, p=0.68, p=0.061, respectively). On the other hand, we found that OS, RFS and CIR were unfavorable in MRD (+) group compared to either MRD negative INT or ADV risk group (35.8 % vs 59.1 % for OS, p=0.05; 24.7% vs 55.9% for RFS, p=0.002; 60.9% vs 20.4 % for CIR, p C onclusions: The ELN 2017 risk classification was not available to predict post-HSCT outcomes in INT and ADV risk group. We found that pre-HSCT MRD rather than ELN 2017 could more likely to predict post-HSCT relapse. The prognostic value of WT1 MRD was more prominent in ELN INT group compared to ADV group. A subset of INT patients had the worst prognosis if their pre-HSCT WT1 MRD remained positive, who they need additional therapeutic strategies to prevent relapse. Figure 1 Figure 1. Disclosures Kim: Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; ILYANG: Research Funding; Takeda: Research Funding. Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria.

Background: Complete remission (CR) rate and long-term overall survival (OS) is very poor in patients with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (R/R BCP-ALL). Previous clinical trials revealed a good remission rate and a safe bridging role to allogeneic-HCT compared to various standard treatments, and several real-world data have been reported. Aim: Here, we analyzed outcome of blinatumomab versus our conventional intensive chemotherapy by propensity score-matched analysis. Methods: From 2009 to 2020, 197 consecutive R/R BCP-ALL were treated with mitoxantrone-etoposide-cytarabine (MEC, n=113) or blinatumomab (n=84), and allogeneic-HCT was planned in patients with CR. For propensity score-matching, the MEC and blinatumomab cohorts were matched in a 1:1 ratio using 5 criteria of age < 35 years old, short CR duration < 12 months, adverse-risk karyotype including Ph-chromosome at relapse, previous allogeneic-HCT, and first-line salvage or not. We compared CR rate, regiment related mortality, and OS with cumulative incidence of relapse (CIR) and non-relapse mortality (NRM). Results: Matched cohort consisted of 52 patients for each salvage group and matched criteria were the same exactly. Median age was 42 years and 34 (65.4%) patients were > 35 years old. There were 22 (42.3%) primary refractoriness, 9 (17.3%) post-chemotherapy relapse and 21 (40.4%) post-HCT relapse. Among 30 relapsed patients, 19 (63.3%) were early relapse with CR duration less than 12 months. There were 25 (48.1%) with poor-risk karyotype at relapse of which 10 were Philadelphia-chromosome. Extramedullary relapse was observed in 14 (26.9%) and 8 (15.4%) were advanced-line salvage. CR rate was significantly higher in blinatumomab (78.8% vs. 53.8%, p=0.012) and more patients proceeded to allo-HCT (80.8% vs. 46.2%, p Conclusion: Our matched cohort analysis clearly showed that blinatumomab is superior to MEC salvage regimen. However, we are observing relapse in up to 50% after blinatumomab and following allo-HCT still shows high NRM. Further combinatorial using novel therapeutics are needed for R/R BCP-ALL. Figure 1 Figure 1. Disclosures Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria. Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction Geriatric assessment (GA) typically refers to a multidimensional evaluation designed to evaluate an older person's functional ability, physical health, cognition, psychological health, nutritional status, and social support. The purpose of GA is to develop time-efficient and straightforward tools to evaluate multiple patient characteristics, which may be predictive of treatment outcomes of elderly acute myeloid leukemia (eAML) patients treated with intensive chemotherapy. Given that there have been few prospective studies with conflicting results, we performed a single-center prospective observational cohort study (#KCT0002172) investigating the prognostic value of multiparameter GA domains for eAML patients' tolerance and survival outcomes after intensive chemotherapy. Patients and methods Newly diagnosed eAML patients aged over 60 years who received intensive chemotherapy (n=105) were prospectively enrolled between November 2016 and December 2019. The median age was 64 years (range, 60-75), and they were all considered fit for intensive chemotherapy, with adequate performance and organ function. All the enrolled patients were administered various questionnaires for pretreatment GA and functional evaluation, which included evaluation for social and nutritional support, cognition, depression, distress, and physical function. Results Of the 105 enrolled patients, 93% had an Eastern Cooperative Oncology Group performance score of 1 and received intensive chemotherapy. Among them, between 32.4% and 69.5% of patients met the criteria for impairment on each GA domain. Physical impairment measured by the Short Physical Performance Battery (SPPB) was significantly associated with non-fatal toxicities of Grade III-IV severe infection (odds ratio (OR) 3.000, 95% confidence interval (CI), 1.159-7.788, p=0.024) and acute renal failure (OR 3.891, 95% CI, 1.329-11.39, p=0.013). Cognitive dysfunction measured by the Mini-Mental Status Examination- Korean version of CERAD Assessment Packet was significantly associated with a higher risk of Grade III-IV infection (OR 2.667, 95% CI, 1.025-6.939, p=0.044) and prolonged hospitalization (OR 4.208, 95% CI, 1.485-4.229, p=0.005). Reduced physical function measured by the SPPB and depressive symptoms measured by the Korean version of Short form Geriatric Depressive Scale (SGDS-K) were predictive of worse overall survival (OS; hazard ratio (HR) 1.917, 95% CI, 1.074-3.420, p=0.027 and HR 1.902, 95% CI, 1.005-3.602, p=0.048). SPPB impairment was also significantly related to higher treatment-related mortality (TRM; HR 2.023, 95% CI, 11.057-3.874, p=0.033). Furthermore, gait or sit-and-stand speed, a component of SPPB, was the single most powerful tool to predict survival outcomes of both OS (HR 2.766, 95% CI, 1.471-5.200, p=0.002 and HR 3.615, 95% CI, 1.868-6.999, p Conclusions We prospectively demonstrated the prognostic value of physical and psychological assessment by GA for survival outcomes in intensively treated eAML patients. Gait or sit-and-stand speed was the single most powerful tool to identify frailty and predict survival outcomes. The prognostic value of preexisting survival prediction models, Wheatley index scores, and AML scores was reconfirmed.. The addition of measures for physical function and depression improved the predictability of those prediction models for survival. Cognitive and physical impairment were able to identify non-fatal toxicities during intensive chemotherapy in eAML patients. Our data will facilitate the incorporation of GA measures into validated survival prediction models to determine initial treatment for eAML patients in routine clinical care and clinical trials. Further studies are warranted to determine the best ways to adjust the care provided for frail patients to improve treatment tolerance and outcomes. Disclosures Kim: Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; ILYANG: Research Funding; Takeda: Research Funding. Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria.

Backgound The Philadelphia-negative myeloproliferative neoplasms (MPNs) share similar molecular characteristics, in which the excessive myeloproliferations are driven by mutations in JAK2, CALR, MPL, and uncommon variants. More recently, the biological basis on acquisition of somatic mutations have been accumulated. However, symptoms, histomorphologic characteristics, and natural histories are different between MPN subsets. Although there are increasing evidences that inflammation have a key role in promoting MPN initiation and influencing disease evolution, characteristics of the bone marrow immune microenvironment between MPN subsets remains unclear exactly. Aims To characterize the bone marrow immune microenvironment of Philadelphia-negative MPNs, we carried out immune-related gene expression profiling of bone marrow aspirates (BMAs) from 33 MPN patients (6 PV, 6 ET, 6 early PMF, and 15 overt MF including 10 primary MF, 5 post-PV/ET MF) using nCounter Immunology Panel. Methods BMA samples collected at diagnosis using EDTA-coated tubes. Those samples were processed within 24 hours from collection to obtain mononuclear cells by density centrifugation using Ficoll-Paque. NanoString analysis using a 594-gene nCounter Immunology panel (Human v2 - nanoString) was performed on RNAs extracted from 33 MPN bone marrow aspirates. Results First, to investigate whether there are distinct gene expression signatures of immune cells between three subcategories of MPNs, we compared gene expression profiles (GEPs) between ET, PV, and overt PMF. Using a P-value cutoff of ≤0.05 and fold-change ≥ 2, 10 upregulated and 32 downregulated differentially expressed genes (DEGs) were identified in ET than PMF, and 9 upregulated and 11 downregulated DEGs were identified in PV than PMF, while we found no significant DEGs between ET versus PV, except seven genes. Second, we investigated differences in GEPs between early PMF and overt PMF. Thirty-two downregulated and 4 upregulated DEGs were identified in early PMF than overt PMF. Gene set analysis revealed that the expression of genes related to almost processes decreased in early PMF than overt PMF. Then, we questioned differences between PMF and post-PV/ET MF. Using a P-value cutoff of ≤0.05 and fold-change ≥ 2, 12 upregulated and 12 downregulated DEGs were identified. Next, we computed relative abundances of immune cell subpopulations, estimated based on expression counts from the entire panel of surveyed genes, and compared them between the subcategories of MPNs. The abundance measurement of exhausted CD8 + T cell genes were significantly lower in ET and PV, compared with overt PMF, suggesting T cell exhaustion was distinct in overt PMF, compared to ET and PV. Conclusions The results demonstrated that immune microenvironment signature was distinguishable in the subcategories of MPNs. In addition, inflammatory signature was enriched in the bone marrow of overt PMF and exhausted CD8 + T cell genes were distinct in overt PMT. Further investigation is warranted to determine the immunological factors critical for potential therapeutic targets to alleviate progress to myelofibrosis. Disclosures Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria. Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction Although many new therapeutic agents have been introduced in the field of AML, the most important intensive induction regimen of AML patients is still 7+3 chemotherapy based on cytarabine and anthracycline. Currently, major guidelines recommend to exam bone marrow (BM) assessment in 14-21 days after the initiation of induction to determine whether to proceed with intensification chemotherapy. However, there is no solid evidence that these timings are most optimal. If the evaluation at an earlier time point is prognostic for response, earlier intensification could be considered. In this regard, we investigated if the BM blast rate at the 7th day after the start of 7+3 chemotherapy (D7 BM blast) was useful in predicting the treatment response of induction chemotherapy. Methods We retrospectively collected the data of patients who were newly diagnosed with AML from February 2002 to February 2021, received induction chemotherapy by 7+3, had a D7 BM examination without any intensification. A total of 665 patients were enrolled and we analyzed the prognostic significance of the D7 BM blast for the induction treatment response (complete remission or complete remission with incomplete hematologic recovery (CR/CRi)). In addition, we analyzed whether the predictive significance of the D7 BM blast varies by the patient's cytogenetic features by Medical Research Council classification (MRC risk). Then, we evaluated the diagnostic ability of the D7 BM blast by the receiver operating characteristic (ROC) curve for treatment response prediction. To find an optimal D7 BM blast cut-off value, the value that maximizes Youden's index was investigated. Results Among 665 AML patients who underwent 7+3 without intensification, the proportion of patients who acquired CR/CRi after single induction was 68.3%. A significant decrease in the CR/CRi rate was observed in the intermediate/adverse MRC group according to the increase of the D7 BM blast (tests for the trends in the intermediate and adverse group, p Conclusion The BM assessment performed at 7 days after 7+3 chemotherapy was available to predict the treatment response in intermediate and adverse cytogenetic risk patients. In particular, it can be practically used in patients with adverse cytogenetics, and a value of around BM blast 5% can be used as cut-off for response prediction. Early intensification in these patients could be considered, which would be beneficial in various aspects such as shorter nadir period or hospital stay and possibly better treatment response compared with the current strategies of later intensification or second induction. Figure 1 Figure 1. Disclosures Kim: Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; ILYANG: Research Funding; Takeda: Research Funding. Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria.

Introduction: Venetoclax (VEN) combined regimen received FDA approval for newly diagnosed elderly or unfit acute myeloid leukemia (AML) patients. Recently, with increasing use as off-label for relapsed or refractory setting in real practice, the evidence that the regimen is potentially effective in R/R AML is emerging. However, there is no answer to the question how VEN combined treatment compares to intensive chemotherapy (IC) in R/R AML when the patients were intended to be cured with bridging to stem cell transplantation (SCT) after either of these treatments. Methods: Adult AML patients (age ≥18 years) who were refractory to or relapsed after anthracycline plus cytarabine induction were subjected to this analysis. As a group of interest, R/R AML patients who received VEN combined regimen were screened first, and we found a total of 54 corresponding patients between Feb 2020 and Jan 2021. As a comparison, we searched historical controls who were treated with salvage IC during the past two years, revealing a total of 89 patients between Jan 2018 and Jan 2020. Patients analyzed here received VEN-combination or IC as their first or second-line salvage therapy. Results: Overall, the median age was 49 years (range, 18 to 72), and the patients of first line salvage (n=125, 87.4%) were more included. When comparing IC and VEN-combination groups, there were no differences in age, sex, ELN risk groups, cytogenetics, disease type or mutation status. However, more patients in VEN-combination group were in their second line salvage setting (IC vs VEN-combination; 5.6% vs 24.1%, p Conclusion: These findings suggest that VEN-combined treatment is a feasible option for R/R AML and could be chosen over salvage IC in R/R AML based on its anti-leukemic response, bridging to SCT with disease control and survival, which were comparable to IC in overall patients and were tended to be superior in patients of first salvage setting only. Disclosures Kim: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AIMS Biosciense: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AML-Hub: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; BMS & Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Boryung Pharm Co.: Consultancy; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Consultancy, Honoraria; LG Chem: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Pintherapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Honoraria, Speakers Bureau; SL VaxiGen: Consultancy, Honoraria; VigenCell: Consultancy, Honoraria. Lee: Alexion, AstraZeneca Rare Disease: Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: venetoclax use in R/R AML: off label use

Introduction Acute myeloid leukemia (AML) has been considered as a hematological emergency. However, debates on how much the time from diagnosis to treatment (TDT) can be justified to choose the optimal treatment in AML have been raised due to the increased possibility of customized treatment with novel targeted agents based on genetic abnormalities tested by newly applicable diagnostic tools. Three recent studies with a large data set from Western countries showed conflicting results about the relationship between TDT and prognosis. Thus, we evaluated the influence of TDT on patients' outcomes from a large data set of Asian patients. Methods We retrospectively evaluated a cohort of AML patients aged 18 and older who visited the Catholic Hematology Hospital in Korea and received anthracycline-based intensive chemotherapy from 2002 to 2016. A total of 1313 patients were included in this analysis, of which 1282 were used for analysis, excluding 26 patients with incomplete documentation and with more than 90 days of TDT. Patients under the age of 60 (Young group, YG) and patients over 60 years of age (Elderly group, EG) were analyzed as an individual cohort. In both cohorts, the effects of TDT on complete remission (CR/CRi), early death (ED), and overall survival (OS) were analyzed. The TDT was analyzed as a continuous variable to minimize the loss of information, while also grouped into four ordinal groups of 1-5, 6-10, 11-15, and 16- to visualize data and find appropriate cutoff. In order to adjust for the influence of established prognostic variables on the outcomes, we used multivariate regression models. In both univariate and multivariate analyses, the transformation of variables or relaxing the linearity such as restricted cubic splining (RCS) were considered to reflect the data properly and not to violate the model assumptions. When TDT was treated as an ordinal variable, the effects of TDT on CR/CRi and ED were evaluated by Cochran-Armitage trend tests, and the effect on OS was checked by the log-rank test. Results Median age of YG (n=1104) and EG (n=178) were 40 years (interquartile range, IQR; 32-49) and 63 years (IQR; 61-64), respectively. Median TDT of both groups was 8 in days (IQR; 6-11 in YG and 6-13 in EG). When TDT was categorized into 4 groups, patients with higher WBC count tended to belong to earlier TDT groups in both YG and EG cohorts, and secondary AML patients were more placed in the later TDT groups especially in YG cohort. Univariate analyses of TDT in YG showed that TDT had significant correlation with CR/CRi rate, ED rate, and OS. Odds ratio (OR) of CR/CRi per one day treatment delay was -0.0206 (95% CI; -0.0412~-0.0000), and OR of ED per one day delay was 0.0439 (95% CI; 0.0126~0.0752) (Table 1 and Figure 1). RCS method was applied on OS model, so a single value of the hazard ratio (HR) per one day treatment delay was not available, but we could say HR of patients of TDT 2 versus (vs.) patients of TDT 16 was 0.6063 (95% CI; 0.4450-0.8259) in our model (Figure 2). Even after TDT was treated as a grouped variable, TDT was still significant on the ED rate and OS in YG. Especially, High ED rate and low 2-year OS of a group of TDT more than 15 days were noticed (Table 1). In EG, there was no significant effect of TDT on all patients' outcomes (Table 1). Multivariate analyses including age, WBC, AML type, MRC risk, and HSCT status showed that, in YG, TDT effect on CR/CRi rate turned to be insignificant, but TDT still acted as a significant variable for ED and OS. In EG, there was no significant effects of TDT on ED and OS, as like univariate analyses. When the treatment course was divided into 'during induction', 'between induction and HSCT', and 'after HSCT' in YG, there was no significant difference in the rate of death between TDT groups except for the deaths during the induction period (Table 3 and Figure 3). Conclusion Our data revealed the effects of TDT on OS and ED in YG, which were significant in multivariate analyses adjusting the effects of other variables. When the timing of death was divided in YG, the only ED was significantly different between TDT groups, especially in the group with more than 15 days of TDT. These results suggest that TDT matters in YG and delayed initiation of treatment over 15 days after diagnosis would increase risk of early mortalities. On the other hand, little effects of TDT on EG provide a rational for sufficient evaluation of comorbidity and functional impairments to select appropriate initial treatment. Disclosures Kim: Takeda: Research Funding; ILYANG: Consultancy, Honoraria, Research Funding; Sun Pharma.: Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Lee:Alexion Pharmaceuticals Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kim:Abbvie: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi-Genzyme: Honoraria; SL VaxiGen: Consultancy, Honoraria; Yuhan: Consultancy, Honoraria; AML Global Portal: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Astella: Consultancy, Membership on an entity's Board of Directors or advisory committees; BL&H: Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Chugai: Consultancy, Honoraria; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Hanmi: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Antihuman T-lymphocyte immune globulin (ATG) was shown to lower the incidence of chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) from an unrelated donor. The type, dose, and duration of ATG treatment is a matter of ongoing controversy in allo-HSCT. Furthermore, there has been no phase 3 study to explore the role of ATG-thymoglobulin for the prevention of cGVHD in allo-HSCT from matched siblings, whereas results from a recent randomized trial of ATG-Fresenius was reported (NEJM 2016). We performed a prospective, single-center, open-label, randomized trial of ATG-thymoglobulin as a part of the conditioning regimen. The primary endpoint was the cumulative incidence (CI) of cGVHD at a 2-year evaluation. A total of 126 patients with acute leukemia were planned to be enrolled and assigned randomly at a 1:1 ratio to receive ATG-thymoglobulin (1.25 mg/kg at three and two days before allo-HSCT) or receive no ATG-thymoglobulin stratified according to the refined Disease Risk Index and conditioning intensity. Both groups were well balanced for NCCN risk, disease type, disease status, and MRD status at HSCT. The current study finally enrolled 120 patients with a median of 560 days of follow-up (range 52 - 1257). The CI of cGVHD in the ATG group (n=60) and non-ATG (n=60) group at 2 years after allo-HSCT was 37.2% and 82.7%, respectively (p In conclusion, the current study revealed that the use of ATG-thymoglobulin, even at a relatively low dose (2.5 mg/kg), decreases the occurrence of cGVHD at a cost of an increased risk for relapse in the setting of allo-HSCT from matched sibling donors for acute leukemia. The optimal dose, timing, and duration of ATG-thymoglobulin should be investigated further. Disclosures Kim: BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sun Pharma.: Research Funding; ILYANG: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Research Funding. Lee:Alexion Pharmaceuticals Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kim:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AML Global Portal: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Hanmi: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BL&H: Research Funding; Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Chugai: Consultancy, Honoraria; Amgen Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Yuhan: Consultancy, Honoraria; SL VaxiGen: Consultancy, Honoraria; AbbVie: Honoraria; Sanofi-Genzyme: Honoraria; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Allogeneic hematopoietic cell transplantation (allo-HCT) preconditioning intensity, donor choice, and graft-versus-host disease (GVHD) prophylaxis for advanced myelofibrosis (MF) have not been fully elucidated. Thirty-five patients with advanced MF were treated with reduced-intensity conditioning (RIC) allo-HCT. We searched for matched sibling (n=16) followed by matched (n=10) or mismatched (n=5) unrelated and familial mismatched donors (n=4). Preconditioning regimen consisted of fludarabine (total 150 mg/m2) and busulfan (total 6.4 mg/kg) with total body irradiation≤ 400cGy. All showed engraftments, but four (11.4%) showed either leukemic relapse (n=3) or delayed graft failure (n=1). Two-year overall survival (OS) and non-relapse mortality (NRM) was 60.0% and 29.9%, respectively. Acute GVHD was observed in 19 patients, and grade III-IV acute GVHD was higher with HLA-mismatch (70% vs. 20%, p=0.008). Significant hepatic GVHD was observed in nine patients (5 acute, 4 chronic), and six of them died. Multivariate analysis revealed inferior OS with HLA-mismatch (HR=6.40, 95%CI 1.6-25.7, p=0.009) and in patients with high ferritin level at post-HCT D+21 (HR=7.22, 95%CI 1.9-27.5, p=0.004), which were related to hepatic GVHD and high NRM. RIC allo-HCT can be a valid choice for advanced MF. However, HLA-mismatch and high post-HCT ferritin levels related to significant hepatic GVHD should be regarded as poor-risk parameters. Disclosures Kim: Handok: Honoraria; Amgen: Honoraria; Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Honoraria; BL & H: Research Funding; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lee:Alexion: Consultancy, Honoraria, Research Funding; Achillion: Research Funding.

Background: Hemophagocytic lymphohistiocytosis (HLH) can be life-threatening if not detected and treated appropriately. Diagnosing HLH can be confusing due to other similar febrile diseases that present with cytopenia. Although a decrease in natural-killer cell (NK)-cytotoxicity is an important diagnostic parameter for primary HLH, the role in adult HLH has not been well-defined. Aim: To identify the diagnostic relevance and the significant cut-off values for NK cytotoxic function, we focused on patients that presented with fever with either cytopenia or evidence of hemophagocytosis. NK cytotoxicity was calculated at the time of diagnosis and we tried to identify significant differences between the causes of disease. Finally, the overall treatment response and survival outcomes were also evaluated based on the level of NK cytotoxicity in several subgroup analyses. Methods: We prospectively enrolled 123 adult patients that presented with fever accompanied by either cytopenia in at least two lineages or marrow hemophagocytosis. A diagnosis of HLH was based on HLH-2004 criteria and treated based on HLH-94 protocol. HLH-suspected patients were initially treated with 10mg/BSA of dexamethasone, and etoposide was considered if clinical improvement was not observed within 7 days after dexamethasone. Patients other than HLH were treated with disease-specified therapy. NK-cytotoxicity was calculated at diagnosis by K562-cell direct lysis using flow-cytometry. Results: HLH (n=60) was determined to be caused by Epstein-Barr virus (EBV, n=11), infection other than EBV (n=16), malignancies (n=19), and unknown (n=14). Febrile diseases other than HLH (n=63) were diagnosed as rheumatologic disease (n=22), malignancies (n=21), infection (n=12), non-malignant hematological diseases (n=6), and unknown (n=2). The results revealed that an HLH diagnosis was significantly correlated with lower NK-cytotoxicity, compared to other diseases (12.1% vs. 26.2%, p Conclusion: We determined that decreased NK-cytotoxicity is a relevant marker that can be used for diagnosis of adult HLH compared with several similar febrile diseases and is also related to poor OS in non-malignant febrile diseases. Based on these results and other prospective studies, we hope that additional relevant diagnostic criteria for adult HLH can be identified in the near future. Disclosures Kim: Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Honoraria; BL & H: Research Funding. Lee:Alexion: Consultancy, Honoraria, Research Funding; Achillion: Research Funding.

Introduction: Recent data emerges that transplantation with reduced intensity conditioning (RIC) seems to be effective as myeloablative conditioning (MAC). However, relapse is a major concern with RIC, and identification of patients at equivalent probability of relapse irrespective of conditioning intensity is needed. Method: A total of 567 AML patients underwent allogeneic hematopoietic stem cell transplantation (HSCT) betwene June 2012 and Jan 2018. For this study, we selected 287 patients who fulfilled i) intermediate or poor risk group by NCCN (2017.Version 3), ii) CR or CRi at HSCT, iii) received either MAC (BuCy or CyTBI) or RIC (FluBu2TBI400) peripheral blood stem cell transplant from 8/8 matched sibling donor (MSD) or matched unrelated donor (MUD), and iv) having bone marrow Wilms tumor gene 1 (WT1) expression results before transplant. The association between conditioning intensity, WT1 level at HSCT and post-transplant clinical outcomes involving overall survival (OS), disease free survival (DFS), cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) were evaluated first. And then we attempted to compare post-tranpslant outcomes between MAC and RIC groups in pre-transplant WT1low patients only. Results: Among the total 287 patients, 232 (80.8%) and 55 (19.2%) patients received MAC and RIC transplant. The median WT1 gene expression level at diagnosis (assessable in 255 patients) was 2310.0 copies/104ABL. When ≥ 250 copies/104ABL were classified as high expression of WT1 (WT1high), 77.3% (n=197) showed WT1high at AML diagnosis. In multivariate analysis, older age and WT1high before HSCT were designated as independent prognostic factor for inferior OS, DFS and higher CIR, and NCCN risk group at diagnosis was significantly associated with incidence of relapse; whereas, conditioning intensity or WT1 level at diagnosis were not prognostic for post transplant outcomes. After excluding patients without available information on initial WT1 level (n=32), whose WT1 levels were not overexpressed at diagnosis (n=58), and whose WT1 level ≥ 250 copies before transplant (n=45), we finally selected 152 pre-trasnplant WT1low patients for further analysis. Older age was still a significant independent factor for poor OS, DFS and higher NRM, whereas NCCN risk stratification at diagnosis was no longer prognostic for post-transplant outcomes in pre-trasnplant WT1low patients only. There was no significant difference in these outcomes between MAC (n=123) and RIC (n=29) patients, and pre-HSCT WT1 level as continuous variable remain significant for predicting relapse even if the level was below 250 copies. Conclusion: Post-transplant survival or relapse did not differ by conditioning intensity in AML CR1 patients whose WT1 level was below 250 copies per 104 ABL at transplant. Figure Disclosures Kim: BMS: Research Funding; Pfizer: Research Funding; Il-Yang co.: Research Funding; Novartis: Research Funding; Takeda: Research Funding. Lee:Alexion: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Achillion: Research Funding. Kim:Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Honoraria; BL & H: Research Funding.

Background The comprehensive geriatric assessment (CGA) typically refers to a multidimensional assessment designed to evaluate an older person's functional ability, physical health, cognition, psychological health, nutritional status, and social support. There is a significant heterogeneity in terms of their underlying health and resilience to the burden of disease and treatments in elderly AML (eAML). To date, a few have evaluated the predictive value of CGA among newly diagnosed eAML. The purpose of this study is to investigate the potential clinical value of CGA as a screening test for frailty in eAML. We designed a comprehensive CGA battery with measures which previously validated, standardized, and widely used. This study is a single-center prospective observational cohort study focused on discriminating between those older patients who are fit for intensive therapies and those who are vulnerable and may experience excess toxicity. Patients and method This prospective cohort study is to investigate the predictive values of each domain of CGA to discriminate vulnerable patients in eAML fit for intensive chemotherapy. Between November 2016 and July 2019, we enrolled newly diagnosed eAML patients aged ≥60 years considered fit for intensive chemotherapy, who had adequate performances and organ functions. All the enrolled patients were administered various questionnaires for an initial CGA and functional evaluation divided into 3 categories; (1) Social and Nutritional support (OARS and MNA), (2) Psychological (MMSE-KC, SGDS-K, PHQ-9, NCCN distress thermometer, MADRS, and KNU-DESC), and (3) Physical function (ECOG, KIADL, SPPB, Handgrip strength, and PTA by professional ENT evaluation). Results Seventy-seven patients were enrolled, in whom the median age of 64 years (range, 60-74), 58.4% were males, and 93.5% and 77.9% of patients had on ECOG score of 0~1 and HCT-CI score of 0~2, respectively. All enrolled patients were treated with intensive chemotherapy, and 62.3% achieved the first complete remission. Three patients experienced early death within 60 days (3.9%). During induction chemotherapy, the median recovery period for neutrophil and platelet counts was 26 (range, 24-29) and 30 (range, 27-33) days, respectively. The median hospitalization days for induction chemotherapy were 32 days (range, 21-104), and infection and GI complications (NCI-CTC-AE based any grade 79.2% and 67.5% respectively) were the most common complications primarily affecting tolerance to the initial chemotherapy. The grade III to IV infection, GI complications, hepatopathy, and acute kidney injury developed in 67.5%, 42.9%, 37.7%, and 16.9% of patients, respectively. Physical impairments were significantly associated with a higher incidence of infection (intact vs. any impairments; 46.4% vs. 79.6%, p=0.003), of which handgrip strength was most accurate tool to predict infection risk (p =0.032), and a trend of more GI complications (intact vs. any impairments; 28.6% vs. 51.0%, p=0.056), resulting in prolonged hospitalization (intact vs. any impairments; 32.2±1.7 days vs. 37.5±2.1 days, p=0.088) for the period of induction chemotherapy. Psychological impairment (intact vs. any impairments; 30.9±1.3 days vs. 38.2±2.1 days, p=0.005), particularly cognitive dysfunction measured by MMSE-KC (p=0.033), was also significantly associated with prolonged hospitalization. Conclusions This data demonstrates that a significant proportion of eAML fit for intensive chemotherapy based on performance status and comorbidity had social, nutritional, physical, psychological impairments by initial CGA assessments. These interim data focusing on early events suggest that impaired physical and/or psychological functions would be useful to identify eAML with intolerance to intensive chemotherapy. This ongoing exploratory prospective study will enroll more eAML patients (targets number=100) and further follow up currently enrolled patients, which will give us invaluable data to develop practical frailty marker and a new model for fitness for intensive chemotherapy. Disclosures Kim: Takeda: Research Funding; Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Il-Yang co.: Research Funding. Lee:Achillion: Research Funding; Alexion: Consultancy, Honoraria, Research Funding. Kim:Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Honoraria; BL & H: Research Funding.

Background: Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a recently recognized high-risk subgroup of T-cell ALL. T-cell ALL is characterized by poorer survival outcomes compared to B-cell ALL, but the optimal treatment strategies are not well elucidated yet. Aim: We performed integrative genetic analyses and tried to find important genetic events in T-cell ALL. We also identified clinical outcomes of T-cell ALL including ETP-ALL subgroup, which were treated with myeloid-suppressive chemotherapy followed by allogeneic hematopoietic cell transplantation (allo-HCT) for post-remission therapy. Methods: We enrolled 40 adult patients with T-cell ALL for analyses of gene mutations and treatment outcomes. Integrative genetic analyses were performed with massive parallel sequencing for NOTCH1, FBXW7, DNMT3A, PHF6, RUNX1, KRAS, NRAS, PTEN, GATA3, EZH2 and SH2B3, and multiplex ligation-dependent probe amplification (MLPA) for copy number alterations of several genes. Among them, quantification of CDKN2A and CDKN2B mRNA expression was performed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). All were treated with myeloid-suppressive chemotherapy which consisted of hyper-fractionated cyclophosphamide (300 mg/BSA, every 12 h, days 1-3), vincristine (1.4 mg/BSA, maximum dose 2 mg, days 4 and 11), daunorubicin (45 mg/m2, days 4 and 11), and dexamethasone (40 mg, days 1-4 and days 11-14) for remission induction, followed by consolidation with high-dose cytarabine (2 g/BSA, every 12 h, days 1-5) and mitoxantrone (12 mg/BSA, days 1-2). Above two anthracycline-intensified regimens were alternatively used for further consolidation. For patients not in complete remission (CR), mitoxantrone (12 mg/BSA, d 1-4), cytarabine (2 g/BSA, every 12 h, d 1-4) and etoposide (100 mg/BSA, d 5-7) were used for reinduction. Our strategy for T-cell ALL in CR was to offer allo-HCT according to the donor availability. Results: We identified 16 patients with ETP-ALL presenting 1 or more stem cell or myeloid marker with absence of CD1a, CD5, and CD8 expression, and 24 patients with non-ETP-ALL. For genetic mutation profiles between ETP-ALL and non-ETP-ALL, we found DNMT3A was more frequently observed in ETP-ALL (25% vs. 12.5%), while FBXW7 (33.3% vs. 6.2%) and RUNX1 (25.0% vs. 0.0%) were more frequently observed in non-ETP-ALL. We also observed that CDKN2A expression was significantly higher in ETP-ALL (0.053 vs. 0.001, p=0.017). In total, 33 (82.5%) patients achieved CR (24 after induction, 9 after reinduction) and their estimated 5-year overall survival (OS) was 31.3% with median survival of 18.9 months. All 16 (100%) patients with ETP-ALL achieved CR (13 after induction, 3 after reinduction), while non-ETP-ALL in 17 (70.8%, 11 after induction, 6 after reinduction) patients. Estimated 5-year OS of ETP-ALL was 41.7% and non-ETP-ALL was 24.3% (p=0.135). Finally, 12 (75.0%) out of 16 ETP-ALL and 11 (45.8%) out of 24 non-ETP-ALL underwent allo-HCT in CR and their 5-year OS was 55.6% and 45.5%, respectively. Conclusion: Our data suggested different genetic predisposition between ETP-ALL and non-ETP-ALL and myeloid-suppressive chemotherapy showed a good CR rate in ETP-ALL. Myeloid-suppressive chemotherapy induced CR followed by post-remission allo-HCT can be a good solution for improving poor survival outcome of ETP-ALL. Disclosures Kim: Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Honoraria; BL & H: Research Funding. Lee:Alexion: Consultancy, Honoraria, Research Funding; Achillion: Research Funding.

Background Either allogeneic hematopoietic stem cell transplantation (SCT) from HLA-matched sibling donor or immunosuppressive therapy (IST) has been recommended as one of the standard treatments for severe aplastic anemia (SAA). Regarding only 30% of chance finding HLA‐matched sibling donor, SCT from an alternative donor including unrelated (URD) or haplo-identical related donor (HAPLO) is considered to be a treatment option after failure to IST in patients who lack of a HLA-matched sibling donor. The aim of this study was to compare the outcomes of URD SCT and HAPLO SCT for SAA patients. Method Consecutive 152 adult patients with SAA who received first SCT between March 2002 and May 2018 were included: 73 of HLA-well-matched (8/8) URD (WM-URD), 34 of HLA-mismatched URD (MM-URD), and 45 of HAPLO. With the intention to have a follow-up period at least 1 year, data were analyzed at May 2019. A conditioning regimen with total body irradiation (TBI) and cyclophosphamide was used for URD-SCT, whereas that with TBI and fludarabine was administered for HAPLO-SCT (Lee et al, BBMT 2011;17:101, Park et al, BBMT 2017;23:1498, Lee et al, Am J Hematol 2018;93:1368). The combination of tacrolimus and methotrexate were used as graft-versus-host disease (GVHD) prophylaxis. Results The median follow-up was 53.4 (range, 0.2-174.1) months. The median age of URD and HAPLO cohort was 30 (range 18-59) and 34 (range 18-59) years, respectively. Except for one and three patients who failed respective a neutrophil and platelet engraftment, other patients achieved neutrophil and platelet engraftments with median 11 and 15 days for WM-URD, 13 and 16.5 days for MM-URD, and 12 and 14 days for HAPLO, respectively. The five-years overall survival (OS), failure-free survival (FFS), and cumulative incidences (CIs) of graft-failure and transplant-related mortality were similar among three groups: 88.3%, 85.5%, 2.7%, and 11.7% for WM-URD; 81.7%, 81.7%, 0%, and 18.3% for MM-URD, and 86.3%, 84.1%, 6.7%, and 9.2% for HAPLO. The 180-days CI of grade II-IV acute GVHD in WM-URD, MM-URD and HAPLO were 35.6%, 52.9%, and 28.9%, respectively; and moderate to severe chronic GVHD were 28.7%, 38.7% and 11.8% in respective cohort. The CI of grade II-IV acute GVHD and moderate to severe chronic GVHD were significantly higher in MM-URD than those in HAPLO (both, p=0.026). ATG is the only factor affecting both grade II-IV acute GVHD (Hazard ratio 0.511, p=0.01) and moderate to severe chronic GVHD (Hazard ratio 0.378, p=0.003) in multivariate analysis. Other complications including CMV DNAemia, hemorrhagic cystitis, invasive fungal disease, secondary malignancy, and sinusoidal obstruction syndrome were similar among three groups. Survival outcomes of a subgroup of ≥ 2 allele MM-URD (n=16) extracted form MM-URD were inferior that of other donor types (n=136): 75.0% vs. 86.9% (p=0.163) for 5-year OS and 75.0% vs. 84.7% (p=0.272) for 5-year FFS. Conclusion This study shows that there were no significant differences between alternative donor sources in the absence of suitable matched sibling donor. Host/donor features and urgency of transplant should drive physician towards the best choice among alternative donor sources for SAA patients treated with SCT. However, selection of ≥ 2 allele MM-URD should not be recommended due to high incidence of GVHD and inferior outcomes. Figure Disclosures Kim: Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; BL & H: Research Funding; Otsuka: Honoraria. Lee:Alexion: Consultancy, Honoraria, Research Funding; Achillion: Research Funding.

Background Transplantation-associated thrombotic microangiopathy (TA-TMA) is a significant complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and may affect 20% of recipients on average. A few groups have proposed risk or prognostic factors for TA-TMA, including a recent prospective study in a cohort that included both children and young adults (Jodele et al. Blood 2014), yet there has been no reproduced or validated data for consensus. Furthermore, with rapid advances in transplantation technology such as an increased variety of donors, conditioning regimens, and graft-versus-host disease (GVHD) prophylaxis, currently used diagnostic criteria and risk factors for TA-TMA must be re-evaluated using recent large cohorts. Patients and method The purpose of this study is to investigate risk and prognostic factors for TA-TMA in adult patients with acute myeloid leukemia (AML). TA-TMA was primarily diagnosed with previously published diagnostic criteria proposed by our group (Cho et al. Transplantation 2010). Then, we analyzed TA-TMA incidence, risk, and prognostic factors in two independent cohorts for training (n = 382, 2012-2015, retrospective) and validation (n = 231, 2016-2017, prospective). In particular, predictive factors for TA-TMA in a prospective cohort, including children and young adults as recently suggested by Jodele et al., were evaluated in our adult AML patients. Results In the entire cohort (n = 613), the median TA-TMA onset was 66 (range, 5-511) days from allo-HSCT. Among TA-TMA patients, 33.6% and 32.6% of them suffered from proteinuria and AKI, respectively. Also, 33.2% suffered from preceding or concurrent hemorrhagic cystitis (any grade), and 12.7% suffered from VOD/SOS at the time of TA-TMA diagnosis. Regarding the treatment of TA-TMA, 87.3% of patients discontinued or reduced the calcineurin inhibitor with supportive care, while 12.7%, 5.6%, and 4.2% were treated with total plasma exchange, t-PA, and defibrotide addition to calcineurin inhibitor dose modification, respectively. Thirty percent of patients achieved complete remission, and TA-TMA was related to poor three-year OS. There were no significant clinical characteristic differences between the training and validation cohorts with the exception of more haploidentical allo-HSCT in the validation cohort (training vs. validation; 26.7% vs. 36.4%, p = 0.012), and the cumulative incidence of TA-TMA was significantly (p < 0.001) higher among the validation cohort (18.8%) than the training cohort (8.9%). For the risk factors of TA-TMA, univariate and multivariate analyses revealed that LDH > 1.5 x upper normal limit (training p = 0.042 and validation p = 0.0042), proteinuria ≥30 mg/dL (training p = 0.0019 and validation p = 0.0012), and ≥Grade I hemorrhagic cystitis (training p = 0.0460 and validation p = 0.0049) were significantly associated with an increased risk of TA-TMA in both the training and validation cohorts. Among patients with TA-TMA, concurrent hemorrhagic cystitis upon diagnosis of TA-TMA was a significant factor for inferior overall survival in the entire cohort (32.3% vs. 5.9%, p = 0.031). Conclusions This study validates the feasibility of diagnostic criteria for TA-TMA proposed by our group with a recent large cohort consisting of training and validation cohorts and points out the role of preceding hemorrhagic cystitis as a risk and prognostic factor for TA-TMA in AML. Of note, proteinuria and elevated LDH prior to the appearance of MAHA proposed by Jodele et al. with a younger population were proven to be useful for predicting the occurrence of TA-TMA among adult populations with AML. Disclosures Kim: Celgene: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Hanmi: Consultancy, Honoraria; AGP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SL VaxiGen: Consultancy, Honoraria; Novartis: Consultancy; Amgen: Honoraria; Chugai: Honoraria; Yuhan: Honoraria; Sanofi-Genzyme: Honoraria, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Handok: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Honoraria; BL & H: Research Funding. Kim:BMS: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Il-Yang co.: Research Funding; Novartis: Research Funding. Lee:Achillion: Research Funding; Alexion: Consultancy, Honoraria, Research Funding.

Background Cytomegalovirus (CMV) establishes lifelong latency after primary infection under the control of the immune system because of the numerous virus evasion strategies that interfere with the host immune response at many levels. Human leukocyte antigen (HLA)-restricted cytotoxic T lymphocytes (CTLs) are involved in the early immune response and are an important defense mechanism in CMV infections, reactivation, and related diseases. Furthermore, an assessment of the clonal diversity of T cell responses against CMV infection provides important insight into the molecular basis of T cell immunodominance. In this single-center study, we tried to demonstrate a specific correlation between the donor HLA genotype and cumulative incidence of CMV reactivation and disease. Patients and methods We retrospectively analyzed 613 donors and recipients diagnosed with acute myeloid leukemia (AML) who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) from matched siblings (n=260), matched unrelated donors (n=167), or haploidentical family donors (n=186) from 2012 to 2017. The CMV-related disease was diagnosed with aggressive procedures in suspicious tissues such as the eyes, gastrointestinal tract, or respiratory tract. The cumulative incidence of overall CMV-related diseases was 12.3% (n=71; range, 9.8 - 15.2), and in each matched sibling, matched unrelated, and haploidentical family donor allo-HSCT group were 6.1% (range, 3.6-9.6), 14.4% (9.2-20.7), and 19.4% (14.0-25.5), respectively. Except for seven patients, all 64 patients developed CMV disease in the CMV reactivation state. We determined the genotypes of the HLA-A, B, C, and DRB1 alleles in 613 donors and recipients by sequencing method and further selected 560 (91.4%) CMV IgG seropositive donors to identify the genetic influence of donor HLA according to CMV infection. Results We first analyzed the relationship between entire donor HLA allotypes and the cumulative incidence of CMV-related disease, then subdivided the donor groups by CMV IgG seropositivity. In the CMV IgG seropositive donor group, we conducted subgroup analysis to identify any difference in CMV-related disease incidence according to types of allo-HSCT. As a result, an entire donor CMV serostatus, three genotype alleles, HLA A*3004 (OR 2.8; p-value 0.044), B*5101 (OR 2.3; p-value 0.003), and DRB1*0901 (OR 2.3; p-value 0.004), demonstrated a statistically significant odds ratio (OR) value with the proper number of patients. However, in the donor CMV IgG seropositive subgroup, two allotypes, HLA B*5101 (OR 2.0; p-value 0.003) and DRB1*0901 (OR 2.7; p-value 0.002), remained. Interestingly, the HLA DRB1*0901 allele showed a concrete association (OR 6.0; p-value HLA-DRB1*1302 showed a promising value as the protective marker (OR 0.2; p-value 0.041) only in the IgG seropositive donor subgroup with the matched unrelated allo-HSCT recipient category. HLA-A*2402 (OR 3.6; p-value 0.048) was only significant in the IgG seropositive donor subgroup with the matched sibling and haploidentical allo-HSCT recipient category. HLA-DR*1501 (OR 2.6; p-value 0.039) was only significant in the IgG seropositive donor subgroup with the matched sibling allo-HSCT recipient category. Conclusion This study demonstrated that certain donor alleles, donor CMV IgG serostatus, and types of allo-HSCT, especially the seropositive donor HLA-DR*0901 allele in the haploidentical allo-HSCT setting, significantly correlated with high CMV-related disease incidence and might be considered risk markers for suitable donor selection. Additionally, the specific donor HLA allele showed either protective or aggravated CMV-related disease incidence in a different allo-HSCT setting. For patients receiving various types of allo-HSCT, a strategic approach to donor selection with careful consideration of donor HLA allotype is important and intensive CMV reactivation monitoring may be required, especially in acute GVHD under active steroid pulse treatment. Disclosures Kim: BMS: Research Funding; Novartis: Research Funding; Pfizer: Research Funding; Ilyang: Research Funding. Lee:Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding.

Background Overexpression of WT1 is a surrogate marker of abnormal myelopoiesis and has been evaluated as a potential tool to assess measurable residual disease (MRD) in myeloid malignancies. Given that lack of consensus on clinically relevant WT1 thresholds and time points in the allogeneic hematopoietic cells transplantation (allo-HSCT) setting, WT1 quantification has not yet gained widespread use despite several pieces of evidence demonstrating the possible role for MRD assessment with the limited numbers of patients. To investigate optimal threshold, time points, and candidates of WT1 quantification in AML, we retrospectively analyzed a large cohort of consecutive patients who underwent allo-HSCT at Catholic Hematology Hospital. Patients and methods This study included 425 consecutive patients with AML who underwent allo-HSCT at CR state from either a matched siblings (n=199), matched unrelated (n=117) or haploidentical family donors (n=109) from 2012 to 2016. Patients were in the first (n=400) or second (n=25) complete remission with a median age of 48 years (range, 18~70). Favorable, intermediate, poor risk groups by 2017 NCCN criteria were 28% (n=120), 49% (n=206), and 23% (n=99), respectively. Bone marrow WT1 levels before, and at 1 or 3 months after allo-HSCT were determined using real-time PCR using the ELN normalized method. We sought to clarify the prognostic relevance of the WT1 quantification regarding the cumulative incidence of relapse (CIR) and survival outcomes. Results With a median follow-up of 39 months (range, two days to 73 months), the 4-year overall survival, disease-free survival, CIR and non-relapse mortality were 63.6%±2.6%, 61.5%±2.6%, 17.9%±2.1% and 24.7%±2.5%, respectively. Analysis of dynamic changes of WT1 levels demonstrated decreased levels at 1 (n=333, mean 86 copies, range 0~1800) and three months (n=346, mean 101 copies, range 0~1670) after allo-HSCT compared to before allo-HSCT (n=425, mean 219 copies, range 0~9630). Relapsed patients had significantly higher WT1 levels before (P=0.018) and at three months (P=0.041) after allo-HSCT, whereas no difference at one month after allo-HSCT (P=0.167). Even the ROC curve analysis revealed that WT1 levels before allo-HSCT were significantly available to predict CIR after allo-HSCT (P In subgroup analyses in each risk group by 2017 NCCN criteria, the WT1-MRD positivity before allo-HSCT was significantly effective to predict CIR in the intermediate risk group (57% vs. 12%, P Conclusions These data suggest standardized bone marrow WT1 levels using the ELN threshold (250 copies) before and at three months after allo-HSCT provided relevant information to predict relapse in AML with intermediate and poor risk groups by 2017 NCCN criteria, respectively. The validated WT1 MRD assay by ELN was revealed to be particularly available in AML without specific MRD markers, such as NPM1 or CBF-AML, and different significance by times points should be considered for clinical applications to identify high-risk AML for relapse, potential candidates for various immunomodulatory approaches. Disclosures Kim: Pfizer: Research Funding; Ilyang: Research Funding; BMS: Research Funding; Novartis: Research Funding. Lee:Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding.

Background: Recently, a high-risk subgroup of B-cell precursor acute lymphoblastic leukemia (BCP-ALL) called Philadelphia chromosome (Ph)-like ALL was identified in adolescents and young adults. However, there are conflicting data regarding the incidence and prognosis of Ph-like ALL in adult patients, and no data have yet been introduced in Asian countries. Aim: We tried to identify the prevalence and genetic characteristics of Ph-like ALL in adult patients with newly diagnosed BCP-ALL. Furthermore, we analyzed the clinical characteristics, long-term outcomes, and prognostic impact of Ph-like ALL compared with non-Ph-like ALL (Ph-positive ALL or BCP-other ALL). Methods: Between December 2008 and March 2016, 334 adult patients with newly diagnosed BCP-ALL who received modified hyper-CVAD chemotherapy and had suitable material for genomic analysis were included in this analysis (median age, 43 years [range, 16-65 years]). Our post-remission therapy was based on allogeneic hematopoietic cell transplantation (HCT) if a donor is available. Ph-like ALL was determined by next generation sequencing using the Archer® FusionPlex® ALL Kit (ArcherDX Inc., CO) which can detect fusions, point mutations, and expression levels in 81 genes associated with ALL and additional FISH analysis was done. Results: Overall, 48 (14.4%) of the 334 patients were Ph-like ALL, and the cohort was divided into patients with ABL1-class rearrangements (n=4), CRLF2 rearrangements (n=11), JAK2 rearrangements (n=4), other JAK-STAT sequence mutations (n=12), and RAS mutations (n=17). The remaining 286 patients had Ph-positive ALL (n=197) and BCP-other ALL (n=89; including 19 patients with KMT2A [MLL] rearrangements). No significant differences in baseline characteristics were observed between the Ph-like ALL and BCP-other ALL subgroups, whereas patients with Ph-positive ALL were older (median age, 47 vs 37 years; p=0.003) and had higher presenting leukocyte counts (median, 33.1 vs 11.4´109/L; p=0.001) compared with Ph-like ALL. The complete remission rate was somewhat different between the 3 disease subgroups (Ph-like ALL, 97.9%; Ph-positive ALL, 95.9%; BCP-other ALL, 88.8%; p=0.027). A higher proportion of patients with Ph-like ALL actually received allogeneic HCT in CR1 than patients with non-Ph-like ALL (Ph-like ALL, 91.6%; Ph-positive ALL, 84.2%; BCP-other ALL, 71.9%; p=0.007). With a median follow-up of 58.1 months (range; 6.0-121.0), outcomes of patients with Ph-like ALL were not inferior compared with outcomes of patients with non-Ph-like ALL. Disease-free survival rates at 5 years were 56.0% for Ph-like ALL, 42.6% for Ph-positive ALL, and 40.6% for BCP-other ALL (p=0.138). The 5-year cumulative incidence of relapse were 19.2% for Ph-like ALL, 35.3% for Ph-positive ALL, and 33.5% for BCP-other ALL (p=0.076). These findings were maintained when only patients receiving HCT were considered. Within the Ph-like ALL subgroup, patients with ABL1-class and CRLF2-rearrangements had worse outcomes than patients with other JAK-STAT sequence and RAS mutations. Also, patients with higher CRLF2 expression had inferior outcomes. Conclusion: Within the limitation of sample size, our data showed a different frequency of subtypes (e.g., lower incidence of CRLF2 rearrangements, higher RAS mutations) and treatment outcomes of adult patients with Ph-like ALL compared with other Western reports. Racial and ethnic differences in the patient population studied may have contributed to these differences. We also suggest that HCT-based post-remission therapy may overcome the poor prognosis of Ph-like ALL. Disclosures Kim: BMS: Research Funding; Ilyang: Research Funding; Pfizer: Research Funding; Novartis: Research Funding. Lee:Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding.

Hematology, Catholic Hematology Hospital and Leukemia Research Institute, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea, 2Department of Biomedical Science, College of Medicine, The Catholic University of Korea, Seoul, Korea, 3Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea Background: Hemophagocytic lymphohistiocytosis (HLH) is a disease showing severe systemic inflammatory cascade which is life-threatening if not detected and treated appropriately. The diagnosis of HLH is confused due to other similar febrile diseases with cytopenia such as severe sepsis, autoimmune disease, and malignancies. Although decreased or absent natural-killer cell (NK) cytotoxicity is known as an important diagnostic parameter for pediatric HLH, the role for adult HLH is not elucidated well and also the significant level is not reported compared to other similar febrile diseases. Aim: We tried to identify the initial level of NK cytotoxicity in several febrile diseases and find out the role for diagnosis of HLH in adult patients in related with several cytokine levels. Methods: We prospectively enrolled 55 patients from 2015 to 2017. Adult patients older than 18 years with fever>38℃ presenting cytopenia in at least two lineages (neutrophil Results: HLH was diagnosed in 37 patients caused by viral infection (n=11), malignancies (n=7), autoimmune diseases (n=5), bacterial infection (n=2), malaria (n=1), anaplasmosis (n=1) and unknown origin (n=10). Febrile diseases other than HLH (n=18) were diagnosed with hematological diseases (n=8), infectious mononucleosis (n=2), rheumatologic disease associated macrophage activation syndromes (n=6), and unknown origin (n=2). The results of both K562 lysis and ADCC assay was well correlated (correlation coefficient = 0.684, 95%CI 0.512-0.804, P Conclusion: We identified that decreased NK cytotoxicity and elevated IL-2R are relevant diagnostic markers for diagnosis of secondary HLH also in adult patients. We also identified ADCC lower than 23.7% was predictable for severe HLH presenting poor treatment outcome. Disclosures Kim: BMS: Research Funding; Ilyang: Research Funding; Novartis: Research Funding; Pfizer: Research Funding. Lee:Alexion Pharmaceuticals, Inc.: Consultancy, Honoraria, Research Funding.

Background: Acute promyelocytic leukemia (APL) is classified into a favorable-risk group and long-term overall survival (OS) is estimated at around 80%. Relapse rate of APL is lower than another acute myeloid leukemia (AML) subtypes, but we confront higher incidence of early deaths caused by fatal complications including bleeding events and differentiation syndromes (DS) during initial therapy. Recently, although arsenic trioxide (ATO) is introduced with a better survival outcome, the results were from data of low to intermediate-risk group. Thus, patients in high-risk group still show poor survival outcome with high probability of early complications and deaths. We calculated the incidence of DS and early deaths, and tried to find out affecting factors for those early events. Methods: In this single center retrospective study, 259 APL patients (median 42 years old (16-72), follow-up was 65.4 months (11.1 - 170.5) from 2002 to 2014 were analyzed. APL was diagnosed by RT-PCR method for detection of PML-RARa and all patients were available with cytogenetic results. All except 5 patients with normal karyotype was identified with t(15;17)(q22;q21) and 77 showed combination of additional karyotypes. All patients were supported with sufficient transfusion and received ATRA. Our treatment protocol was based on the modified AIDA protocol using ATRA and idarubicin monotherapy (Sanz et al. Blood. 1999; 94: 3015-21) but some patients with comorbidity were treated with ATO, low-dose cytarabine, and ATRA alone for remission induction. For hyperleukocytosis, we conducted leukapheresis when leukocyte counts exceeded 50 (x109/L) and some were treated with hydroxyurea, cytarabine and prophylactic dexamethasone. High-risk group was determined according to the Sanz criteria which presented leukocyte count > 10 (x109/L) at diagnosis. For leukocyte count, we checked diagnostic level (WBCdx) and the maximal level (WBCmax) during initial therapy and identified a group which showed a meaningful increment of WBCmax compared to WBCdx. Results: ATRA was applied in 258 patients and 217 (84.1%) were treated with idarubicin, 13 (5.0%) were with ATO, 3 (1.2%) were with low-dose cytarabine. Eight-week cumulative incidence of early death and DS was 13.5% and 17.8%, and hematological CR was identified in 222 (86.0%) patients. Five-year OS and EFS was 76.8% and 69.8%, and CIR rate was 15.7%. Six patients showed clonal evolution to therapy-related AML and 3 patients died in CR. FLT3-TKD and FLT3-ITD mutation was identified in 12 (7.3%) and 34 (20.7%) patients, and PML-RARa BCR3 and BCR1 subtype was identified in 70 (36.8%) and 120 (63.2%) patients, respectively. For leukocyte counts, except for WBCdx higher than 43 (x109/L), which showed significantly higher rate of early death and DS, patient groups with WBCdx 43 (x109/L) and low antithrombin III were significant for DS, while old age, WBCmax, and high D-dimer were associated with early death. In our data, dexamethasone prophylaxis did not show a preventive effect for DS or early death, while leukapheresis in patients with WBCmax >43 (x109/L) showed marginally decreased early death rate `resulting superior OS without significant bleeding complications. Conclusion: Our data revealed WBCmax with higher increment ratio was a significant predictive factor for early death and DS compared to WBCdx even in the low Sanz-risk group. The role of dexamethasone, transfusion support including antithrombin III, leukapheresis or cytoreduction should be evaluated in the specific patient subset for reducing early events in APL. Disclosures Kim: ILYANG: Consultancy, Honoraria, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Lee:Alexion Pharmaceuticals, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Background: Although recently, Eculizumab, humanized monoclonal antibody directed against complement component C5, has used increasingly for the patients with hemolytic paroxysmal nocturnal hemoglobinuria (PNH), allogeneic stem cell transplantation (allo-SCT) can be curative treatment option especially for PNH patients with combined aplastic anemia (AA). The aim of the present study was to evaluate long-term outcome of allo-SCT in patients with AA/PNH. In addition, patients with classic PNH who underwent allo-SCT in the pre-eculizumab era were also evaluated. Methods: Total of 33 patients with PNH clones underwent allogeneic SCT at our institution between Jan 1998 and Jan 2016. Among them, seven patients had classic PNH and 26 patients with cytopenia had AA/PNH (with bone marrow evidence of a concomitant AA). Results: There were 21 male and 12 female patients with a median age of 34 years (range, 13-56 years). Pre-transplant GPI-AP deficient neutrophils and erythrocytes were 5.6% (0-92) and 21% (0-98.5), respectively. Median white blood cell, absolute neutrophil count, hemoglobin, and platelet at transplant were 2.4×109/L, 0.8×109/L, 7.7 g/dL, and 27×109/L, respectively. Median LDH level was 727 U/L (232-7721 U/L) and 19 (58%) patients had LDH ≥1.5x upper limit of normal. Classic PNH (n=7) and AA/PNH [SAA (n=15), VSAA (n=9), or non-SAA (n=2)] received SCT from HLA-matched sibling (MSD, n=24), unrelated (URD, n=7), or haplo-identical donor (Haplo-SCT, n=2). Since 2003, the conditioning regimen for MSD-SCT was changed from Busulfex (12.8 mg/kg) + cyclophosphamide (CY, 120 mg/kg) to fludarabine (180 mg/m2) + CY (100 mg/kg) + rATG (10 mg/kg). The conditioning regimen for URD-SCT and Haplo-SCT were TBI (800 cGy) + CY (100-120 mg/kg) ± rATG (2.5 mg/kg) and TBI 600cGy + Fludarabine (150 mg/m2) + rATG (5 mg/kg), respectively. After a median follow-up of 57 months (range 6.0-151.3), the 5-year estimated OS rates were 87.9 ± 5.7%. Four patients died of treatment-related mortality (TRM), including acute GVHD (n=1), pneumonia (n = 2), and cerebral hemorrhage (n=1), respectively. Except one patient with early TRM, 32 patients engrafted. Two patients who experienced delayed graft-failure received second transplant and recovered. The cumulative incidence of acute GVHD (≥grade II) and chronic GVHD was 27.3 ± 7.9% and 18.7 ± 7.0%, respectively. Among 25 patients with available follow-up data, PNH clone disappeared at median 3.0 months (range 0.7-45.5) after SCT and reemerging of PNH clones was observed in two patients; one patient showed re-appearance of 2.6% GPI-negative neutrophils at 12 months without PNH symptoms, but disappeared again at 21 months. Another patient suffered from labile graft and received a booster with peripheral blood stem cells. Conclusion: This study showed that long-term transplant outcome in patients with AA/PNH were comparable to that of allogeneic SCT in SAA (the 3-year estimated OS rates were 92.7 and 89 % for MSD-SCT and URD-SCT, respectively) at our institution (ASH Annual Meeting Abstracts 2012;120:4151). Reduced-intensity conditioning regimen was sufficient for the eradication of PNH clone in allogeneic SCT. Therefore, application of allogeneic SCT should be considered in PNH patients with AA in case of availability of well matched donor. Disclosures No relevant conflicts of interest to declare.

Background: On the basis of the characteristics of extranodal natural killer T (NK/T)-cell lymphoma (ENKTL) which is predisposed to have the multidrug resistance phenotype and radiosensitivity, combined chemotherapy-radiotherapy is one of the effective options in localized early-stage, ENKTL, nasal type. However, frequent severe myelosuppression (grad 3/4 cytopenia), grade 3 radiation-related mucositis, and local/systemic relapse is a major obstacle. So we evaluated the proMACE-cytaBOM (prednisone, methotrexate, doxorubicin, cyclophosphamide, etoposide, cytarabine, bleomycin, vincristine, and methotrexate) as a slightly less intense regimen with sandwiched radiotherapy (36 Gy). Patients and Methods: From July 2005 to December 2014, Thirty-one patients with newly diagnosed, stage IE to IIE, nasal type ENKTL were analyzed retrospectively. Twenty patients received the chemoradiotherapy sandwiched method: Initially 3 cycles of proMACE-cytaBOM, followed by radiotherapy of 36 Gy, after sandwiched radiotherapy and additional 3 cycles of proMACE-cytaBOM were administered. The other eleven patients were treated with following: Two patients received the frontline autologous hematopoietic stem cell transplantation, five patients were treated with sequential chemoradiotherapy as VIPD (etoposide, ifosfamide, cisplatin, and dexamethasone) followed by radiation of 50 Gy. Four patients received the chemotherapy alone (4 to 6 cycles of proMACE-cytaBOM). Results: In twenty patients with completely proMACE-cytaBOM and sandwiched radiotherapy schedule, median age was 50-year (range 26 to 79), with male-dominant (85%). A median of 6 (range, 4-6) cycles of proMACE-cytaBOM were administered, and sandwiched radiotherapy was received with a median 36 Gy (range 34.5 to 36) (Table1). Interim analysis after 3 courses of proMACE-cytaBOM showed that an overall response rate (ORR) of 82.6%, with complete remission (CR) and partial remission (PR) achieved in 73.9% and 8.7%, respectively. On treatment completion with chemotherapy and sandwiched radiotherapy, the ORR was increased to 90.0%, with CR rate increased to 85%. One patient experienced disease progression, and the other one was within stable disease during therapy. With a median follow-up of 42 months (range 5.5 to 81.4), the 5-year overall survival and progression-free survival were 83.6% (95% CI, 69 to 95 %) and 45.9% (95% CI, 45 to 95%), respectively (figure 1). Grade 3/4 neutropenia developed in 25% (n=5) of patients and grade 3 radiation-related mucositis in 10% (n=2). There was no regimen treatment-related mortality (TRM) (Table 2). Conclusion: The proMACE-cytaBOM regimen with sandwiched radiotherapy (36 Gy) could be a promising and feasible option in the treatment of newly diagnosed localized ENKTL due to its favorable efficacy and tolerable low toxicities including of low radiation-related mucositis and no TRM. Table 1 patient demographic and characteristics Table 1. patient demographic and characteristics Table 2 major adverse events of therapy in twenty patients with localized ENKTL Table 2. major adverse events of therapy in twenty patients with localized ENKTL Figure 1 Overall survival and progression-free survival after combined chemotherapy with sandwiched radiotherpay Figure 1. Overall survival and progression-free survival after combined chemotherapy with sandwiched radiotherpay Disclosures No relevant conflicts of interest to declare.

Background: Human leukocyte antigen (HLA) matching between donor and recipient is a key part of successful allogeneic hematopoietic cell transplantation (allo-HCT). The HCT from the unrelated donor (UD) with one allele/antigen mismatch (MM) can be as beneficial as HCT from perfectly matched donor. For the remaining patients, the donors with permissive mismatches may be the option. In HLA-mismatched transplantation, the patient and donor can also be mismatched for their killer cell immunoglobulin-like receptor (KIR) ligands that recognize allotypic determinants shared by certain HLA class I allele groups. Recent research has accumulated evidence of the role of each HLA locus and KIR ligand MM on clinical outcomes for UD-HCT. However, HCT outcomes of the patients with permissive MM depending on KIR ligand MM (KIR-L-MM) status remain obscure in UD-HCT. In the current study, we identified permissive and nonpermissive MM allele combinations and analyzed the effects of these mismatches in combination of KIR ligand mismatches in patients with acute myeloid leukemia (AML). Methods: A total of 438 patients with AML who underwent allo-HCT from UD from 2007 to 2014 were analyzed. Alleles of patients and donors at the HLA-A, -B, -C, and -DRB1 loci were identified by the high resolution DNA typing. Nonpermissive HLA allele combinations were defined as a significant HLA risk factor for severe acute graft-versus-host disease (aGVHD). KIR-L-MM among patient-donor pairs were searched in the Immuno Polymorphism Database available at www.ebi.ac.uk/ipd/kir. Results: Median age of the patients was 45 (range 15-60) years and 117 patients (40.4%) were female. Eighty-five (19.4%) patients were high risk at the time of HCT. Reduced intensity conditioning was performed in 131 patients (29.9%) and anti-thymocyte globulin was used in 324 patients (74.0%). Primary graft source was peripheral blood stem cells (n=369, 84.2%) and median 6.0 x 106/kg cells were infused. Severe aGVDH occurred in 43 patients (9.8%) and chronic GVHD (cGVHD) in 193 (44.1%). With median follow-up duration of 19 (range, 2-96) months, treatment-related mortality (TRM) occurred in 111 patients (25.3%), relapse in 119 (27.2%) and death in 214 (48.9%). Two-hundred sixty-four patients (60.3%) were HLA full matched in the 4 loci. Mismatches in HLA-A loci observed in 64 patients, HLA-B in 35, HLA-C in 98, and HLA-DRB1 in 60. Five nonpermissive MM pairs in 33 patients were identified as donor/patient pair: A*02:06/A*02:01, C*03:03/C*08:01, C*08:01/C03:04, C*08:01/C*15:02, and DRB1*04:03/DRB1*04:05. Among 98 patients with HLA-C loci MM, 16 patients showed KIR ligand MM (KIR-L-MM) as GvH direction, which was observed in the permissive MM group. Severe aGVHD occurred in 30.4%, 22.4%, 13.4%, and 10.8% in nonpermissive, permissive MM and KIR-L-MM, permissive MM and KIR-L-M, and full match group, respectively (p=0.003). The 3-year overall survival (OS) rate was inferior in permissive MM and KIR-L-MM group (30.0%) compared to full match (53.5%), permissive MM and KIR-L-M (51.8%), and nonpermissive (42.4%) group (p=0.067). The 3-year TRM was higher in permissive MM and KIR-L-MM group (57.5%) than full match (21.0%), permissive MM and KIR-L-M (27.7%), and nonpermissive (33.3%) group (p=0.006). In the multivariate analysis, high risk at HCT (HR 2.087, p6x106/kg (HR 4.113, p=0.017) were high risk factors on severe aGVHD. Conclusion: Permissive MM for HLA could be further classified into high risk groups with regard to TRM by KIR-L matching in UD-HCT. The evaluation of KIR-L matching is warranted to reduce unfavorable outcomes among the patients with permissive MM in UD-HCT. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Background: The use of tyrosine kinase inhibitor (TKI)-based chemotherapy has demonstrated improved complete remission (CR) rates and increased applicability to allogeneic hematopoietic cell transplantation (HCT), thus allowing better survival in adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). However, the sensitivity of Ph-positive ALL to reduced-intensity conditioning (RIC) versus myeloablative conditioning (MAC) by minimal residual disease (MRD) kinetics is not well established. Previously, we have confirmed that monitoring MRD kinetics is very important to predict long-term outcomes. Here, we examined a cohort of patients with Ph-positive ALL in CR1 and tried to compare the long-term outcomes of RIC-HCT vs MAC-HCT according to pre-HCT MRD kinetics. Methods: During the period between 2000 and 2014, 173 adults (median age, 39 years [range, 16-65 years]) with Ph-positive ALL were included in this analysis. All patients received allogeneic HCT (68 RIC [fludarabine 150mg/m2 + melphalan 140mg/m2] and 105 MAC [total body irradiation 13.2Gy + cyclophosphamide 120mg/kg]) in CR1 following two courses of first-line TKI (138 imatinib and 35 dasatinib)-based chemotherapy and had data on prospectively determined quantitative MRD kinetics. A total of 52 patients were excluded because of >CR1 pre-HCT status (n=26), transplants receiving umbilical cord blood grafts (n=14), and no TKI use before HCT (n=12). All but one RIC transplants received peripheral blood stem cells as a graft source (40 matched sibling donor, 11 matched unrelated donor, 17 mismatched unrelated donor), while MAC transplants used either bone marrow (n=73; 57 matched sibling donor, 8 matched unrelated donor, 6 mismatched unrelated donor) or peripheral blood stem cells (n=32; 2 matched sibling donor, 20 matched unrelated donor, 10 mismatched unrelated donor). The median time to transplant was 154 days (range, 119-291 days) in RIC transplants and 141 days (range, 112-280 days) in MAC transplants, respectively. Calcineurin inhibitors (cyclosporine for sibling donor transplants, tacrolimus for unrelated donor transplants) and methotrexate was used for graft-versus-host disease (GVHD) prophylaxis and antithymocyte globulin was administered to the patients who received mismatched unrelated donor grafts. If residual leukemia was detected in the absence of GVHD at 3 months after transplantation, calcineurin inhibitors were rapidly discontinued. MRD monitoring was centrally evaluated by real-time quantitative PCR (4.5 log sensitivity) through handling of bone marrow samples. Results: After a median follow-up of 70.4 months (range, 16.0-176.8 mo), RIC regimen showed comparable 5-year cumulative incidence of relapse (CIR; 30.2% vs 27.9%, P=0.750), non-relapse mortality (NRM; 20.3% vs 15.5%, P=0.318), disease-free survival (DFS; 49.7% vs 56.6%, P=0.296), and overall survival (OS; 59.3% vs 62.1%, P=0.540) compared to MAC regimen. We further analyzed the impact of conditioning intensity on CIR and DFS according to MRD kinetics. Based on the MRD kinetics during the pre-HCT TKI-based chemotherapy courses, we classified patients into 3 subgroups: early-stable molecular responders (EMR, n=59), late molecular responders (LMR, n=57), and poor molecular responders (PMR, n=53). In all MRD-based subgroups of patients, no significant difference in CIR (EMR: 16.3% vs 6.2%, P=0.280; LMR: 10.5% vs 21.4%, P=0.334; PMR: 63.6% vs 59.4%, P=0.372) or DFS (EMR: 68.1% vs 78.1%, P=0.381; LMR: 49.6% vs 59.5%, P=0.369; PMR: 27.3% vs 34.2%, P=0.250) was observed between RIC and MAC. In multivariate analysis, LMR (HR, 2.36; 95% CI, 0.81-6.86; P=0.114) or PMR (HR, 9.05; 95% CI, 3.40-24.1; P Conclusion:RIC-HCT showed comparable long-term outcomes to MAC-HCT in all MRD-based subgroups of patients with Ph-positive ALL in CR1. Our data suggest that RIC-HCT is worthy of further investigation in prospective trials of adult Ph-positive ALL. Disclosures Kim: ILYANG: Consultancy, Honoraria, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Background Although the combination of lenalidomide and low-dose dexamethasone (Len-dex) is known to preserve the efficacy with reduced toxicity than lenalidomide plus high-dose dexamethasone (Len-Dex) in patients with refractory/relapsed multiple myeloma (RRMM), infection is still a leading toxicity. Moreover, the patterns and risks for infection in patients with RRMM during Len-dex treatment remain unclear and there is a need to identify contributing factors associated with increased risk for infection. Considering the disease-related and treatment-related immune deficits in patients with RRMM, we explored the predictive implications of the revelation of the immune cell populations prior to Len-dex initiation for the occurrence of infection. In addition, the various clinical and laboratory parameters were analyzed. Methods Clinical and microbiology records of 90 RRMM patients during Len-dex treatment were reviewed and risk factors for infection were analyzed using the logistic regression. In addition, to develop the new immune cell biomarker, we prospectively examined immune cell populations (CD3, CD4CD161, CD8CD161, Lin-HLA-DR-CD11b+CD33+, CD14+HLA-DR-, NK and NKT cells) of the peripheral blood taken on baseline of Len-dex therapy. Results Forty-eight men and 42 women were enrolled in this study. The median age was 61 years (range, 29-84 years). During a median 11 cycles of Len-dex treatment, 52 (57.8%) patients experienced at least 1 infection episode. Of a total of 92 episodes of infection, 58 (63%) episodes were clinically defined, 29 (31.5%) episodes were microbiologically defined, and 5 (5.4%) episodes were fever of unknown focus. Severe episodes were frequently observed during early 3 cycles. In the univariate analyses, lower Hb ( Conclusions We demonstrated several clinical predictive factors for the occurrence of infection in patients with RRMM receiving Len-dex treatment. And we found that the frequency and absolute count of CD4+CD161+ cells may provide additional information for predicting the occurrence of infection in early period of Len/dex therapy. Disclosures No relevant conflicts of interest to declare.

Background Recent advances in controlling graft failure and graft-versus-host disease (GVHD) due to barrier of HLA incompatibilities in haplo-identical stem cell transplantation from related mismatched donor (Haplo-SCT) extended its application to severe aplastic anemia (SAA). Therefore, studies for searching optimal conditioning regimen and strategy of graft manipulations for SAA patients who receive Haplo-SCT are needed. This prospective study was aimed to explore the optimal conditioning regimen to ensure engraftment with minimal toxicity in adult patients with SAA who received Haplo-SCT. Methods We have explored a safe and sufficient dose of ATG in combination with 800 cGy TBI and fludarabine (Flu, 30 mg/m2/day) for 5 days using step by step dose de-escalation based on the transplant-related mortality (TRM) and toxicity. The dose of ATG was de-escalated from 10 mg/kg (group 1), 7.5 mg/kg (group 2), to 5 mg/kg (group 3) and from October 2014, the TBI dose also reduced to 600 cGy with fixed dose of Flu and ATG (5mg/kg) (group 4). If any patient developed TRM with engraftment in each group, we moved to next group. For GVHD prophylaxis, a combination of tacrolimus and short-course methotrexate was used. G-CSF mobilized PBSCs were used as stem cell source without manipulation. Considering the importance of both survival and GVHD rate when testing conditioning regimen, GVHD-free survival, defined as grade 3-4 acute GVHD, chronic GVHD requiring systemic treatment, or death was addressed. Results Twenty-nine patients including 18 men and 11 women were enrolled. The median age was 31 (17-52) years. Median CD34+ cells transplanted were 5.84x106/kg (1.45-16.2). All patients achieved primary engraftment. Thirteen patients (7 of 10 in the group 1-3, 6 of 19 in the group 4) had CMV DNAemia requiring pre-emptive therapy including 3 patients with CMV disease (2 pneumonia, 1 colitis). Three patients (2 in the group 1, 1 in the group 2) developed EBV-associated PTLD, of whom two patients with monomorphic type received rituximab and chemotherapy. The incidence of acute GVHD (grade ≥2) and chronic GVHD (≥ moderate) were 24% and 17%, respectively. With a median follow-up of 41.4 (31.9-48.9) months in the group 1-3 and 10.1 (1.3-20.6) months in the group 4, probability of overall survival (94.1% in the group 4 vs. 70% in the group 1-3, P = 0.292) and GVHD-free survival (73.3% in the group 4 vs. 50% in the group 1-3, P = 0.161) were improved in the group 4. Conclusions This study explored the optimal conditioning with step by step de-escalation dose of ATG and TBI to reduce TRM with sustained graft function. TBI-600 cGy/Flu/low-dose ATG resulted in feasible outcomes of Haplo-SCT for adult patients with SAA. Disclosures No relevant conflicts of interest to declare.

Background: Therapy-related acute myeloid leukemia (t-AML) is regarded as a complication after cytotoxic chemotherapy and/or radiation therapy, and also considered to have a poor survival outcome compared to de novo AML. We still have a question whether t-AML itself indicates a poor prognosis or whether the inferior outcome results from the association with such an adverse characteristics including cytogenetic risk or age or underlying malignancies. Methods: In this single center retrospective study, 1825 patients (median 46 years old [range, 17-92]) with variable karyotypes were enrolled from 2002 to 2013. Fifty-four (3.0%) patients had previous malignancies or autoimmune diseases, and all of them were treated with radiation or toxic chemotherapy before diagnosis of t-AML with a median duration of 36.3 months (range, 2.9-280.5). We analyzed clinical outcomes compared to 1771 de novo AML patients who were not related with any toxic therapies before. Results: Among 54 t-AML patients, 42 (77.8%) was in remission of prior malignant disease and 8 were in stable disease and 4 were in relapsed disease. In t-AML subgroup, median age was older (50 vs. 46 years old, p =0.119), leukocyte and bone marrow blast counts were significantly lower than de novo AML subgroup. There were more female patients in t-AML subgroup (70.3% vs. 45.4%, p=0.003). Among 38 female t-AML patients, 13 (34.2%) patients had breast cancer, 10 patients had hematological malignancies (i.e. APL in 5, lymphoma in 3, multiple myeloma in 2), and 8 (21.1%) had gynecological malignancies (i.e. ovarian and cervical cancer etc.). One or more chromosomal abnormalities (82.6% vs. 68.3%, p=0.015) and more adverse-risk karyotypes (41.2% vs. 20.0%, p50 years old (HR=1.48, p Conclusion: In this study, t-AML was related with a larger proportion of adverse-risk karyotype, and many patients could not start induction chemotherapy due to old age, and remained prior malignant disease, which might result in poor survival outcome. On the other hand, response to induction chemotherapy of t-AML was similar with de novo AML consistent with a recent report (Kayser et al. Blood 2011). Therefore, if previous malignancy is in remission or in stable disease, aggressive treatment strategy using HCT may overcome poor survival outcome of t-AML. Disclosures No relevant conflicts of interest to declare.

Background: Myeloid-derived suppressor cells (MDSC), a heterogeneous group of myeloid cells, have emerged as immune regulators, having a high potential to suppress T cell responses. Although uniform characterization of human MDSC needs to be elucidated, they can be divided into the categories of granulocytic (G-MDSC) and monocytic (M-MDSC). Recent studies have reported that MDSC, generated in vitro or in vivo, alleviated the severity of graft-versus-host disease (GVHD) in murine allogeneic transplant models and in human delayed M-MDSC reconstitution was associated with the occurrence of acute GVHD. However, whether G-MDSC and M-MDSC may have different role on the outcomes after allogeneic stem cell transplantation (SCT) remains obscure. Methods: This prospective study was aimed to identify the clinical implications of early G-MDSC and M-MDSC expansion as a predictor for the occurrence of acute GVHD (aGVHD), infections, CMV reactivation, and survival outcomes after allogeneic SCT. The peripheral blood samples from 130 patients with acute myeloid leukemia and myelodysplastic syndrome-refractory anemia with excess blasts, who underwent allogeneic SCT between Jan. 2013 through Oct. 2014 were taken at engraftment and analyzed by flow cytometry. Results: Seventy-eight men and 52 women were enrolled in this study. The median age was 45.5 years (range, 17-68). To compare the predictive role of MDSC for various transplants, the patients were grouped according to the median values of the frequency of G-MDSC and M-MDSC. High G-MDSC at engraftment was a potential factor promoting the occurrence of ≥ grade 2 aGVHD at 100 days (30.8% vs. 47.7%, P = 0.023), whereas high M-MDSC group had no difference in the occurrence of ≥ grade 2 GVHD compared that of low M-MDSC group. There was no difference in CMV reactivation, infection rate, and TRM according to G-MDSC recovery. In contrast, patients in the high M-MDSC group had a higher cumulative incidence of infection at 100 days (25.1% vs. 48.2%, P = 0.002), and TRM (6.4% vs. 22.6%, P = 0.018), compared with the patients in the low group. Ultimately, multivariate analyses reveal that high G-MDSC had a trend for the occurrence of ≥ grade 2 GVHD at 100 days (RR 1.72, 95%CI (0.95-3.11), P = 0.071) and high M-MDSC could predict a higher infection rate (RR 2.30, 95%CI (1.30-4.07), P = 0.004) and higher transplant related mortality (TRM) (RR 3.30, 95%CI (1.10-9.90), P = 0.033). In addition, high M-MDSC was associated lower event-free survival (P = 0.008). Conclusion: Our data demonstrated that the high G-MDSC in the peripheral blood at engraftment was associated with a trend toward higher incidence of aGVHD and high M-MDSC was an independent factor for infection and TRM. Discrepancy of the role of G-MDSC and M-MDSC after allogeneic SCT suggests that difference of MDSC reconstitution into the more differentiated subset may predict transplant outcomes, including aGVHD, infections, and TRM. Disclosures No relevant conflicts of interest to declare.

Background: Lenalidomide combined with low-dose dexamethasone (Len-dex) is an effective treatment for the patients with refractory/relapsed multiple myeloma (RRMM). The anti-myeloma effect of lenalidomide is associated with activation of the immune system, but the exact immunomodulatory mechanisms in vivo and clinical impact of Len/dex in RRMM patients remains unclear. In this study, we analyzed immune cell populations in patients receiving Len-dex for the treatment of RRMM. Methods: Peripheral blood samples from 90 RRMM patients were taken on day 1 of cycles 1 (baseline), 2, 3, and 4 of Len/dex therapy. CD3+, CD4+, CD8+, CD161+ T cells, natural killer (NK) cell (CD16+/CD56+), NKT-like cell (CD3+/CD56+) and myeloid-derived suppressor cell (MDSC) including granulocytic (G-MDSC) and monocytic (M-MDSC) were analyzed by flow cytometry. In addition, response was assessed in 81 patients receiving more than 4 cycles of Len-dex and the comparison of cell populations according to an achievement of ≥very good partial response (VGPR) was performed. Results: Forty-eight men and 42 women were enrolled in this study. The median age was 61 years (range, 29-84 years). At baseline, peripheral blood CD3+ cell frequency was 51.65 ± 1.79% which was significantly decreased to 41.67 ± 2.44% (P=0.001) and 39.72 ± 2.90% (P< 0.001) after 2 and 3 cycles of therapy, respectively. Frequency of both CD4+ cell and CD8+ cells was also significantly decreased by 3 cycles of therapy, while NK cell frequency was significantly increased after Len-dex treatment (P Conclusion: Our data demonstrate that Len-dex therapy in patients with RRMM is associated with decreased frequency of T cells with a trend of increased NK cell frequency. Change in CD8+ cell and M-MDSC frequency can correlate with the quality of response to Len-dex. Baseline NKT-like cell frequency and change in CD3+ and CD8+ cells early after treatment may predict continuation of anti-myeloma effect of Len-dex therapy. Disclosures No relevant conflicts of interest to declare.

Background: Standard therapy for intermediate to high-risk acute myeloid leukemia (AML) consists of several hematopoietic cell transplantation (HCT) strategies including autologous-HCT (AUTO), allogeneic-HCT from matched-sibling donor (MSD) or well-matched unrelated donor (WM-URD). When a conventional donor is not available, HCT from partially-matched unrelated donor (PM-URD) or familial mismatched/haploidentical transplantation (FMMT) or umbilical cord blood transplantation is also considered for an alternative choice. Although HCT outcomes of those alternative strategies are advancing with optimization of pre-conditioning regimens with immunosuppressive agents, there are still subjects to debate. We tried to analyze the long-term HCT outcomes according to the donor types including FMMT and PM-URD as an alternative choice. Methods: We enrolled 561 AML patients (median 41 years old, range: 16-68) in complete remission (CR) who were transplanted in Catholic BMT Center in Korea from 2002 to 2013. Patients in at least second CR were excluded. All patients presented intermediate to high-risk karyotype according to the NCCN guidelines, and all of the patients received standard 3+7 chemotherapy followed by consolidation chemotherapy. In the absence of MSD and WM-URD, we allocated PM-URD or AUTO as an alternative choice first, and then FMMT was considered. We divided patients according to the 5 donor types (i.e. MSD (n=252), WM-URD (n=112), PM-URD (n=41), AUTO (n=104), and FMMT (n=52)), and survival outcomes with the cumulative incidence of relapse (CIR), non-relapse mortality (NRM), acute/chronic GVHD and CMV reactivation were analyzed. Results: Engraftment was successful and showed similar recovery pattern in all donor types. Our data showed mismatch in ABO, sex, and certain HLA locus was not influential, and stem cell source and conditioning-intensity were not also influential for survival outcome and incidence of GVHD. After median follow-up of 54.3 month (range: 6.6-145.6), MSD, WM-URD and FMMT showed similar 5-year OS around 62% except for AUTO at 47.4% and PM-URD at 36.7%. DFS at 5-years was 59% for MSD, 56% for WM-URD, 62% for FMMT, 44.3% for AUTO, and 33.5% for PM-URD. Five-year CIR rate was highest in AUTO (50.3%) followed by PM-URD (33.1%) and WM-URD (29.8%). Lower CIR-rate was identified in MSD (22.4%) and FMMT (21.4%), and the lowest NRM rate was identified in AUTO subgroup (5.1%) followed by WM-URD (11.4%), FMMT (15.6%) and MSD (18.0%). PM-URD showed the highest NRM rate (33.3%) with higher incidence (26.7%) of Gr°Ã3 acute GVHD compared to 9.3% of MSD. Incidence of chronic GVHD was not significantly different. In adverse-risk subgroup, 5-year OS of MSD, WM-URD, and FMMT was 46%, 47%, and 58% respectively, while AUTO and PM-URD was 11% and 0%, which was caused by significantly higher CIR rate of 79.7% and 83.5%, respectively, compared to 31.1% of MSD. In intermediate-risk subgroup, 5-year OS of AUTO (55.2%) was not inferior to that of MSD (67.2%, p =0.330) or FMMT (64.9%, p =0.451), which showed the highest CIR rate (42.8%) and the lowest NRM (5.4%). PM-URD also showed highest NRM (39.4%) with high incidence (27.3%) of Gr°Ã3 acute GVHD. Conclusions: FMMT should be considered prior to PM-URD in intermediate to adverse-risk AML and GVHD prophylaxis should be intensified when we have to use PM-URD. AUTO might be considered in intermediate-risk AML in selected patients and prospective study should validate the utility of FMMT or AUTO in addition to the conventional donor types. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.

Background The prognostic impact of serum ferritin level has been well established in patients with myelodysplastic syndrome and acute myeloid leukemia (AML) in the context of allogeneic hematopoietic stem cell transplantation (Allo-HSCT). However, the clinical safety and efficacy of iron-chelation therapy (ICT) for adult AML with hyperferritinemia post-Allo-SCT has not been evaluated. Materials and methods We retrospectively evaluated 320 consecutive patients with de novo AML who received Allo-HSCT at complete remission in a single institution between January 2007 and February 2012. Serum ferritin levels were monitored from initial diagnosis to the several time points during the post-transplantation period in both the ICT group (n=113) and the non-treated group (NT, n=191). In the ICT group, ICT was started at least a month after transplantation when serum ferritin levels over 1,000 ng/mL, and continued to the ferritin level lower than 500 ng/ml unless serious adverse effects and/or relapse. Sixteen patients treated less than one month with ICT due to early complications, such as infection(n= 10, 62.5%), liver toxicity (n=4, 25%), and poor compliance (n=2, 12.5%) were excluded in the ICT group. The baseline characteristics between two groups were not significantly different. Results The median treatment duration in ICT group was 6.4 months (range, 1.0-49.2) with dosage of 20-40 mg/kg/day. Deferasirox treatment was discontinued at least one time in 43 patients (38%) in ICT group due to toxicities and/or poor compliance, but almost patients (n=40, 93%) could be treated again with deferasirox without further toxicities. High serum ferritin level of pre-Allo-HSCT over 1,000 ng/ml was significantly associated with poor overall survival (OS, 52.2% vs. 75.4%, HR 0.78, P Conclusion Our data demonstrate that ICT with deferasirox was well tolerable in AML with hyperferritinemia after Allo-SCT, and suggest the independent association of ICT with increased incidence of chronic GVHD and decreased relapse. Iron chelation may modulate of immunobiologic properties during the period of immune reconstitution (low level of Treg cells and higher CD16+ NK cells, 2014 ASH Abstract #2543) and/or induce direct anti-leukemia effect by iron depletion, which need to be further evaluated. Disclosures No relevant conflicts of interest to declare.

Background: Acute promyelocytic leukemia (APL) is classified into favorable-risk group and long-term overall survival (OS) is estimated at around 80%. Relapse rate of APL is relatively lower than another acute myeloid leukemia (AML) subtypes, but we still confront relapse in 10-20% and some relapsed cases are hardly cured even after hematopoietic cell transplantation (HCT). Therefore, it is important to find out patients with high-risk of relapse and early intervention should be considered. In APL, PML-RARa RQ PCR is used as a marker for residual disease, but the marker is not useful for pre-emptive management for relapse prevention because its positivity directly indicates relapse of disease. WT1 expression is a well-known marker in AML, and the expression is higher in APL than the other AML subtypes (Cilloni et al., leukemia, 2002). We monitored WT1 decrement along the treatment courses to identify its significant role as a marker for relapse prediction. Methods: In this study, 117 APL patients with a median follow-up duration of 38.5 months (range, 9.7-81.3) from 2008 to 2014 were analyzed. APL was diagnosed by RT-PCR method for detection of PML-RARa and all patients were available with cytogenetic results. All except 5 with normal karyotype was identified with t(15;17)(q22;q21) and 33 (28.2%) showed combination of additional chromosomal abnormalities. Our treatment protocol was based on LPA99 trial using ATRA and idarubicin monotherapy (Sanz et al., Blood, 2004). In relapsed patients, we applied ATO and some high-risk patients were treated with HCT (n=3). PML-RARa and WT1 expression in the BM samples were quantified by RQ-PCR method, and we used WT1 ProfileQuant¢â kit (Ipsogen) for WT1 monitoring. We measured RQ-PCR levels at diagnosis, post-induction and each of the 3 post-consolidation chemotherapies, and 3 months interval after starting maintenance therapy. FLT3- ITD/TKD mutation was evaluated by multiplex allele-specific PCR and concomitantly analyzed. Significant cut-off level of PML-RARa and WT1 expression was calculated by ROC curve analysis. According to the level, we calculated OS, disease free survival (DFS), and cumulative incidence of relapse (CIR). Results: Hematological complete remission (CR) was identified in 117 (100.0%) patients but complete molecular remission (CMR) was identified in 68 (42.7%) after induction. Among 49 patients who failed to achieve CMR, 44 patients achieved CMR after 1st consolidation and 5 patients after 2nd consolidation. Three-year OS and EFS was 92.5% and 82.0%, and CIR rate was 14.7% (n=13). Three patients showed clonal evolution to therapy-related AML and 1 patient died in CR due to lung cancer. FLT3 -TKD and FLT3 -ITD mutation was identified in 6 (5.1%) and 25 (21.4%) patients, and PML-RARa BCR3 and BCR1 subtype was identified in 32 (27.4%) and 85 (72.6%) patients, respectively. For relapse prediction, we analyzed WT1 expression at several time points in association with CMR after induction, FLT3 -ITD/TKD mutation, BCR subtype, and hyperleukocytosis at diagnosis and during first chemotherapy. High WT1 expression (>120 copies/104ABL1) in early period (3 months) after maintenance therapy significantly predicted subsequent relapse. All paired PML-RARa RQ-PCR was not detected except one sample with early relapse after 3rd consolidation. Patients with high post-maintenance WT1 expression (n=40) showed significantly higher CIR rate (30.7% vs. 4.2%, p=0.0003) and inferior 3-year OS (86.1% vs. 97.9%, p =.0103) and DFS (62.8% vs. 94.1%, p Conclusion: High post-remission WT1 expression was a reliable marker for the prediction of subsequent relapse in APL, even when PML-RARa was not detected at 3 months post-maintenance. In this high-risk group, early intervention with ATRA±ATO, WT1 vaccination or WT1 -specific cytotoxic cell therapy may be used for relapse prevention. The role of WT1 expression needs to be validated by prospective studies in a large cohort. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures No relevant conflicts of interest to declare.

Background: For elderly patients unfit for intensive chemotherapy in acute myeloid leukemia (AML), low-dose cytarabine (LDAC; 20 mg SQ BID for 10 days) still remains to be the standard treatment, despite its unsatisfactory complete response (CR) rate of 18% and median overall survival (OS) of < 6 months (Burnett, 2007). Recently, there have been huge efforts to develop more effective and less-toxic therapies, such as decitabine, azacitidine, clofarabine, or gemtuzumab ozogamicin, but their benefits were not concrete, even though they were compared to the classical LDAC. To improve outcomes of the classical LDAC, we modified it by giving a higher dose of cytarabine for an extended duration in combination with oral etoposide. Herein, we present the results. Methods: Between 2002 and 2014, 93 consecutive older (≥ 60 years) patients with AML, who were unfit for intensive chemotherapy, received 1st cycle of modified LDAC (mLDAC) regimen consisting of cytarabine (20 mg/m2 SQ BID) and oral etoposide (50 mg PO BID) for 14 days. Thereafter, they received additional subsequent cycles (for a maximum of 7 cycles) for 10 days every 6 to 8 weeks. We retrospectively analyzed their overall response (OR), disease-free survival (DFS), and overall survival (OS) rates. In this analysis, OR was defined as CR plus CR with incomplete platelet recovery (CRp) or blood count recovery (CRi). Results: The median age of patients in our cohort, including 69 (74.2%) with poor performance status (ECOG ≥ 2), 15 (16.1%) with AML with myelodysplastic-related changes or secondary AML, and 13 (14.0%) with poor cytogenetic risk, was 68 years (range, 60-83). The median number of mLDAC regimen cycles which they received was 2 (range, 1-8). Clinically relevant toxicities of grade III-IV including nausea/vomiting, diarrhea, hyperbilirubinemia and neutropenic fever were observed in 4 (4.3%) patients, 6 (6.5%), 3 (3.2%), and 42 (45.2%), respectively, which were comparable with those of classical LDAC (Burnett, 2007). The early mortality rates at 30 and 60 days were 11.8% and 15.0%, respectively. The OR was observed in 45 (48.4%) patients, including 34 (36.6%) CR, 7 (7.5%) CRp, and 4 (4.3%) CRi, within two cycles of mLDAC. With median follow-up duration of 26.1 months, the median DFS and OS were 6.2 and 15.8 months, respectively. For patients who achieved OR, they were 14.5 and 36.9 months, respectively. The OR of patients who had poor cytogenetic risk was not significantly different compared to others (57.1%, 46.2%, and 38.5% for favorable, intermediate, and poor cytogenetics, respectively; P=0.50). However, they showed significantly shorter median DFS (9.8, 6.6, and 5.1 months, respectively; P=0.01) and OS (NR, 1.4, and 5.1 months, respectively; P=0.01) with significantly shorter OR duration (30.6, 19.1, and 8.6 months, respectively; P=0.01). Between 2009 and 2014, among 17 patients treated with hypomethylating agents (HMA; 14 decitabine and 3 azacitidine), 1 CR and 3 partial response were achieved with a median survival of 5.5 months, and 5 patients after HMA treatment failure received subsequent mLDAC, and 3 achieved additional CR (n=2) and CRp (n=1). Conclusions: These results suggest that the outcomes of classical LDAC in elderly patients with AML can be improved by modifying it, with improved response and survival rates without increasing toxicities, even in patients with poor cytogenetics. Additionally, mLDAC could induce clinical responses in patients with HMA failure. Our mLDAC regimen may become another therapeutic option with emerging novel agents for elderly patients with AML, and these should be confirmed by large randomized trials. Disclosures No relevant conflicts of interest to declare.

Surviving leukemic stem cells (LSCs) after chemotherapy lead to relapses in acute myeloid leukemia (AML). Because LSCs will not be eradicated after standard chemotherapy, inhibiting the propagation of AML cells by LSCs is a major part in AML treatment. Although CD34+CD38- cells in leukemia are representative LSCs, it is still difficult to distinguish them apart from normal hematopoietic stem cells (HSCs). So far, many studies have shown rapid advances in phenotypic characterization. However, heterogeneous diversity in AML patients may not allow effective eradication of LSCs. Vascular endothelial growth factor receptors (VEGFR)-3 is expressed in AML blasts and in the bone marrow (BM) environment including sinusoidal vessels. In particular, VEGFR-3 is strongly correlated with poor prognosis, leukemic cell proliferation and survival in AML. Based on previous reports, we were able to hypothesize that VEGFR-3 is expressed in LSCs and functions as a LSC marker. Here, we observed high expressions of VEGFR-3 on CD34+CD38− cells in AML patients who received chemotherapy and further showed low homing and engraftment capacity of CD45dim blast cells in the BM by a VEGFR-3 antagonist. In order to determine the expression of VEGFR-3 on LSCs, data was collected from 64 AML patients, 12 of whom were after complete remission (CR), as well as from 14 healthy volunteers. MNCs were first isolated and were then subjected to FACS analysis and immunocytochemistry. NOD-Scid IL2RγNull mice were used for homing efficiency and engraftment in vivo. MAZ51 was used as a VEGFR-3 antagonist. FACS analysis showed that VEGFR-3 was increased on CD34+CD38− LSC cells. (Normal vs. AML vs. CR, VEGFR-3 on CD34+CD38- cells: 8.33 ± 4.37% vs. 25.62 ± 2.46% vs. 23.46 ± 5.47%, P < 0.05). Similarly, immunocytochemistry clearly displayed the co-expression of VEGFR-3 on isolated CD34+CD38− LSC cells, suggesting the possibility of it as a LSC marker. We checked the ability of LSCs to use colony forming units assay. VEGFR-3+CD34+ cells showed unarguably enhanced colony forming ability compared to that of VEGFR-3-CD34+ cells from patients. To test whether VEGFR-3-CD34+ cells are not on apoptotic procedure, annexin-V and proliferation assay with Ki67 were performed, and there was no difference in apoptotic and proliferative movement in both cells. Intending to determine homing efficiency and engraftment, CD34 and CD45 markers were used in the BM and it was discovered that sorted VEGFR-3+CD34+CD38- cells showed significantly increased homing and engraftment efficiency compared to those of VEGFR-3-CD34+CD38- cells (by FACS, homing capacity: 1.93 ± 0.19% vs. 0.13 ± 0.06%, P = 0.02; engraftment: 26.4 ± 9.42% vs. 5.30 ± 2.31%, P < 0.05), implying that VEGFR-3 can serve as a marker for LSCs. We demonstrated that VEGFR-3 was highly expressed and enriched on CD34+CD38- cells in CR status as well as in the initial diagnosis of AML. Therefore, the targeting of VEGFR-3 may diminish LSC function in human AML. These findings could suggest some clues to develop therapeutic strategies targeting VEGFR-3+ LSCs with favorable tumor microenvironments. Disclosures No relevant conflicts of interest to declare.

Background: The ferritin contents in immature myeloid cells could be detected in both iron overload and in AML. Ferritin itself in leukemic cells could be regarded as an important marker for leukemic activity. Serialreports have shown that the serum ferritin level in patients with acute leukemia and myelodysplastic syndrome is a critical prognostic factor after hematopoietic stem cell transplantation (HSCT). However, the exact mechanism itself is not clear. Methods: We evaluated the iron chelating efficacy and the immunomodulatory effect of deferasirox therapy as assessed by regular monitoring of serum ferritin levels and immunocyte subsets from the post-induction period to post-HSCT. In addition, we tried to reveal the effects of deferasirox on various clinical outcomes in patients with adult AML who were expected to receive allogeneic HSCT. A total of sixty-six consecutive adult patients with de novo AML who received allogeneic HSCT were prospectively enrolled during the period 2009 to 2011. Serum ferritin levels were monitored from initial diagnosis to the post-HSCT period from both the iron-chelated group (IC, n=28) and the non-treated group (NT, n=38) of patients. Among the patients of the IC group, the final 20 AML patients were followed and were collected peripheral blood samples until minimum 6 months post-HSCT. The overall median follow-up for total survivors (IC) was 58 months (range: 48~66). Deferasirox treatment was initiated at the outpatient clinic both after induction chemotherapy and post-HSCT 1 month. Various clinical outcomes in association with multiple parameters including serum ferritin levels and multiple immunocyte subsets of CD4, CD8, CD16, CD56, invariant NKT, Treg, central/effector memory T cells were simultaneously analyzed, mainly in the IC group of patients, with the usage of the multi-color flow cytometer at pre- and post-HSCT periods. Results: The median duration of total (pre- + post-HSCT) medication in IC group of patients was 241 days (109-452). The median ferritin levels at diagnosis (IC, 651 ng/mL vs. NT, 667 ng/mL) and at peak levels (IC, 3,090 ng/mL vs. NT, 3,685 ng/mL) during chemotherapy did not differ significantly between groups. However, pre-HSCT levels were different between groups, as the median level of 1,555 ng/mL (335-3,800) (IC) vs. 964 ng/mL (229-7,360) (NT). The 5-year overall survival (OS) and event-free survival (EFS) rates of total AML patients were 63.6% and 60.6%, respectively. The Kaplan-Meier estimates of OS/EFS rates were all significantly different in pre-HSCT ferritin levels (P=0.0247, 0.0212) and duration of deferasirox treatment both pre- (P=0.028, 0.0166) and post-HSCT (P=0.0102, 0.0064). The levels of CD4+CD62L-CD44+ (P=0.027) and CD8+CD62L-CD44+ cells (P=0.006) post-induction chemotherapy were significantly associated with the duration of deferasirox treatment before HSCT. To note, the levels of CD4+ cells at 1 month post-HSCT deferasirox treatment (P=0.017), CD4+ effector memory T (TEM)-cells pre-HSCT (P=0.029), and CD8+CD62L-CD44+ cells post-HSCT 1 month (P=0.003) and 6 months (P=0.021) were closely related to the relapse of AML. Most of all, regulatory T (Treg) cells both pre-HSCT (P=0.002) and post-HSCT (P Conclusion: Our data suggest that despite small sample numbers, iron-chelation therapy for adult AML patients with hyperferritinemia pre- and post-HSCT is very closely related to the outcomes of allogeneic HSCT, and that it is especially associated with the modulation of immunobiologic properties during the period of immune reconstitution. Therefore, more cautious approaches to reduce iron overload by using iron chelating agents, such as deferasirox, may be warranted both before and after allogeneic HSCT. Disclosures Kim: Novartis Korea: Research Funding.

Background:Paroxysmal nocturnal hemoglobinuria (PNH) is a nonmalignant clonal disorder of hematopoietic stem cells characterized by a somatic mutation in the PIG-A gene, encoding the glycosyl phosphatidylinositol (GPI) moiety. PNH clones lack GPI-anchored proteins (GPI-AP) which inhibit the activation and cytolytic functions of complement. Recently, Eculizumab, humanized monoclonal antibody directed against complement component C5, has used increasingly for the patients with hemolytic PNH. However, the patients with PNH clone and bone marrow failure syndrome (i.e. aplastic anemia) should be treated as their predominant clinical manifestation. Allogeneic stem cell transplantation (SCT) can be curative treatment option especially for PNH patients with combined aplastic anemia (AA). The aim of the present study was to evaluate long-term outcome of allogeneic SCT in patients with AA/PNH. Methods: Total of 27 patients with PNH clones underwent allogeneic SCT at our institution between Jan 1998 and Mar 2014. Among them, seven patients had classic PNH and 20 patients with cytopenia had AA/PNH (with bone marrow evidence of a concomitant AA). We analyzed long-term transplant outcomes in 20 patients with AA/PNH. Results: There were 12 male and 8 female patients with a median age of 34 years (range, 13-51 years). The median interval from the diagnosis to transplantation was 8 months (range; 1-201 months). The median transfusions prior to SCT were 33 units (range; 8-208 units). Pre-transplant GPI-AP deficient neutrophils and erythrocytes were 46% (0-99) and 15.6% (0-88), respectively. Median white blood cell, absolute neutrophil count, hemoglobin, and platelet at transplant were 2.3×109/L, 0.7×109/L, 7.9 g/dL, and 21×109/L, respectively. Median LDH level was 714 U/L (range; 273-6499 U/L) and 11 (55%) patients had LDH ≥1.5x upper normal limit. PNH patients with SAA (n=14), VSAA (n=4), or non-SAA (n=2) received SCT from sibling (s) donor (n=15) or unrelated (u) donor (n=5). The conditioning regimen for s-SCT consisted of fludarabine (180 mg/m2) + cyclophosphamide (CY, 100 mg/kg) + ATG (10 mg/kg) (n=11), or busulfex (12.8 mg/kg) + CY (120mg/kg) (n=4). The conditioning regimen for u-SCT was TBI (fractionated, 800 cGy) + CY (100-120 mg/kg) ± ATG (2.5 mg/kg). GVHD prophylaxis consisted of CsA + MTX in s-SCT and FK506 + mini-MTX in u-SCT, respectively. After a median follow-up of 57 months (range 4.7-122.1), the 5-year estimated OS rates were 90.0 ± 6.7%. Two patients died of treatment-related mortality (TRM), including acute GVHD (n=1) and cerebral hemorrhage (n=1), respectively. Except one patient with early TRM, 19 patients engrafted with no secondary graft-failure. The cumulative incidence of acute GVHD (≥grade II) and chronic GVHD was 25.0 ± 1.0% and 26.3 ± 10.4%, respectively. PNH clones disappeared at median 1.8 months (range 0.9-11.9) after SCT and reemerging of PNH clone was not observed in all patients. Conclusion: This study showed that long-term transplant outcome in patients with AA/PNH were comparable to that of allogeneic SCT in SAA (the 3-year estimated OS rates were 92.7 and 89 % for s-SCT and u-SCT, respectively) at our institution (ASH Annual Meeting Abstracts 2012;120:4151). Therefore, application of allogeneic SCT should be considered in PNH patients with AA in case of availability of well matched donor. Disclosures No relevant conflicts of interest to declare.

Background: Severe aplastic anemia (SAA) is a life-threatening bone marrow failure disorder. Immunosuppressive therapy or allogeneic stem cell transplantation (SCT) are recommended depending on severity of the disease, patient's age and availability of donor. In addition, many patients require blood transfusions as supportive management, which lead to the development of iron overload. Previous studies have shown a negative impact of pretransplant iron overload on overall survival (OS), mortality, and infection in patients undergoing allogeneic stem cell transplantation (SCT). Although the use of oral iron-chelating agent, deferasirox, has been increased, the impact of pretransplant iron chelating therapy (ICT) on the transplant outcomes in patients with SAA was uncertain. Methods: This study included 109 iron overloaded patients with SAA who underwent allogeneic SCT between March 2002 and December 2012. All patients had available pretransplant serum ferritin data. Among them, 50 patients were received pretransplant ICT with deferasorox, when their serum ferritin was more than 1000 ¥ìg/L, whereas 59 patients had more than 1000 ¥ìg/L of serum ferritin but did not received ICT (era before availability of deferasirox). Results: Fifty-five men and 54 women were assessed. Their median age was 34 years (range, 15-59 years). The patients received grafts from either a HLA identical sibling (N=55) or an unrelated donor (N=54). Primary engraftment was achieved in all, but 5 patients developed secondary graft failure. After a median follow-up of 38.3 (range, 6.1-124.9) months for survivors, there was not statistical difference of overall survival (OS) between the patients with ICT and those without ICT (82.3% vs 89.9%, P=0.455). Of note, the possible survival benefit of pretransplant ICT was observed in unrelated transplant setting (93.5% vs. 78.3%, P=0.090). Pretransplant ICT group showed a lower infection rate after SCT compared to those without ICT (34% vs. 59%, P=0.008). For 50 patients receiving pretransplant ICT with deferasirox, median serum ferritin levels decreased from 1995 ¥ìg/L at the initiation of ICT to 1240 ¥ìg/L before SCT. Median duration of ICT before SCT was 3.6 months (range, 0.3-44.2 months), and mean daily dose was 14.8 mg/kg per day. The patients who achieved more than 650 ¥ìg/L decrement of serum ferritin levels from ICT initiation to SCT had a higher OS than the patients with less than 650 ¥ìg/L (96.7% vs. 80.0%, P=0.044). Conclusion: These results indicate that iron overload was associated with a negative impact on outcome after SCT in SAA. Pre-SCT ICT can reduce the incidence of infection after SCT and the possible survival benefit of Pre-SCT ICT was present especially in unrelated donor SCT. Among the patients receiving pretransplant ICT, significant decrement of serum ferritin is a favorable prognostic factor after allogeneic SCT in iron-overloaded patients with SAA Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

In western countries, several studies have reported that CMV seronegative acute leukemia (AL) patients might have a beneficial effect from CMV seropositive donor for reduction of relapse. These observations resulted from subclinical CMV viremia with delayed initiation of antiviral therapy which showed a stimulatory effect on natural-killer cells and cytotoxic T-cells that may enhance graft-versus-leukemia (GVL) effect. We tried to evaluate the relationship between CMV reactivation and relapse of AL in Korean population, in which CMV serostatus is mostly positive for both donors and recipients. Three hundred eighty-nine AL patients with AML (n=197), ALL (n=192) who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first remission between 2007 and 2011 were retrospectively analyzed. Most of the donors (95.1%) and recipients (98.7%) were CMV seropositive. After engraftment, we serially measured CMV RQ-PCR once a week for surveillance of CMV reactivation and generally initiated preemptive ganciclovir (GCV) therapy when the titer reaches over 15,000copies/mL. Below 15,000, patients without GVHD were observed with tapering immunosuppressive agents. To evaluate the anti-leukemic activity of CMV viremia, patients with early death ( In the entire group, CMV viremia was an adverse factor for OS (p Our data showed the possible GVL effect associated with CMV reactivation measured by RQ-PCR. This finding should be evaluated by larger validated studies to disclose the role of CMV reactivation in AL in the CMV seropositive population. Disclosures: No relevant conflicts of interest to declare.

Background The successful induction chemotherapy of acute myeloid leukemia (AML) depends on the ability to achieve complete remission (CR) and to maintain remission status as long as possible. Approach to improve the rate of CR includes the intensification of induction chemotherapy for AML. The primary goal of this study was to evaluate and compare the long-term outcomes between remission induction therapy with and without early intensification added to the standard 3+7 remission induction regimen. Methods A retrospective analysis was performed on de novo AML patients diagnosed and treated at Catholic Blood and Marrow Transplantation Center between January 2001 and December 2010. Six hundred forty-one adults of ages between 16 and 60 were included, all of whom received induction chemotherapy starting with 3 days of idarubicin and 7 days of cytarabine or behenoyl cytarabine (BHAC). Cases with t(9;22) and t(15;17) were excluded. Bone marrow (BM) aspiration study was assessed on day 7 of induction in all patients. Factors which were considered for early intensification of induction were the presence of ≥ 5% BM blasts, patient performance, and other high risk clinical characteristics, such as karyotype. Groups according to early intensification on days 8 to 10 of induction were as followings: no intensification (3+7), n=156; cytarabine or BHAC for 3 days (3+10), n=233; addition of idarubicin for 2 days to 3+10 regimen (5+10), n=252. After a median duration of 5.5 months (3.3-19.0) from diagnosis, 479 patients underwent stem cell transplantation (autologous [auto-SCT], n=144; allogeneic [allo-SCT], n=335). Conditioning regimen for auto-SCT consisted of fractionated total body irradiation (TBI), melphalan, and cytarabine, whereas 83% (n=278) of patients with allo-SCT received myeloablative conditioning, of which was mostly TBI-based regimen (92%). Donors were matched sibling (n=213), matched unrelated (n=63), mismatched unrelated (n=39), and haploidentical related (n=20). Results The median age at diagnosis was 39 years (16-60). Mean values of BM blast % on day 7 of induction was 3.5 in 3+7 group, 7.9 in 3+10, and 33.6 in 5+10 (p= Conclusion Our results suggest possible benefit of examining day 7 BM aspiration for the strategy of early intensification of induction chemotherapy for adult AML patients and our intensification doses can be safely added with high efficacy in the achievement of CR1 compared to 3+7 standard regimen, and may have affected for better DFS after allo-SCT. Disclosures: Kim: BMS: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

Background Allogeneic stem cell transplantation (SCT) from matched-sibling donor (MSD) and immunosuppressive treatment (IST) are the most widely used first-line treatments for patients with severe aplastic anemia (SAA). Overall long-term survival rates are comparable between the two groups. However, patients with age of over 40 have not been generally considered as candidates of SCT from MSD (MSD-SCT) due to higher transplant-related mortality. Recent improvements in MSD-SCT such as less intensive fludarabine-based conditioning, and use of rabbit anti-thymocyte globuline (ATG) instead of horse ATG as first-line IST may change these results. Therefore, we compared the clinical outcomes between MSD-SCT with fludarabine-based conditioning and IST with rabbit ATG and cyclosporine A (CsA). Methods We analyzed the clinical results of 54 adult SAA patients who were treated with MSD-SCT and 93 with IST as a first-line treatment from March 2006 to May 2012 at Seoul St. Mary’s Hospital, Seoul, Korea. The patients who were treated with MSD-SCT received conditioning with fludarabine (30 mg/m2/day × 6 days), cyclophosphamide (50 mg/kg/day × 2 days), and rabbit ATG (Thymoglobulin®, 2.5 mg/kg/day × 4 days). Those who were treated with IST received rabbit ATG (2.5 mg/kg/day × 5 days) with CsA. Results The median ages were not significantly different between the MSD-SCT group and IST group (38.5 years vs. 43.0 years; P=0.103). Other baseline characteristics were comparable except the interval from diagnosis to treatment (100 days vs. 40 days; P=0.013), absolute lymphocyte count (0.68 × 109/L vs. 0.93 × 109/L; P=0.013), and platelet count (10.0 × 109/L vs. 11.0 × 109/L; P=0.035). In the IST group, overall response and complete response rates at 1 year were 44.1% (95% CI, 33.8-54.8) and 10.8% (95% CI, 5.3-18.9). Treatment failure developed in 55 (59.1%) patients due to non-response in 34 (36.6%), relapse in 5 (5.4%), clonal evolution in 3 (3.2%), and treatment-related mortality in 13 (14.0%) patients. After treatment failure, 17 (18.3%) patients received SCT from MSD or unrelated donor. In the MSD-SCT group, 10 (18.5%) patients experienced treatment failure due to secondary graft failure in 5 (9.3%), clonal evolution in 1 (1.9%), and treatment-related mortality in 4 (7.4%) patients. Among the patients who experienced secondary graft failure, 4 (7.4%) patients received secondary SCT, which resulted in sustained graft function. Consequently, overall survival (OS) at 3 years in the MSD-SCT group was not significantly different compared to that in the IST group (90.7% vs. 81.0%; P=0.139). However, the MSD-SCT group showed significantly higher failure-free survival (FFS) at 3 years compared to the IST group (80.2% vs. 46.6%; P Conclusions Our data suggest that MSD-SCT is more favorable than IST as a first-line treatment, considering the curative nature of MSD-SCT even in patients over 40 years of age. Disclosures: No relevant conflicts of interest to declare.

Background In the setting of unrelated donor stem cell transplantation (URD-SCT), several data showed that peripheral blood stem cells (PBSC) resulted in faster engraftment but increased the risk of acute or chronic graft-versus-host disease (GVHD), while other transplant outcomes were comparable. However, there are some limitations in these data due to heterogeneous diseases or registry data characterized by various other treatment strategies. Notably, we have added low-dose rabbit anti-thymocyte globuline (ATG) only to the patients who received URD-SCT with PBSC because of their higher risk of developing GVHD. In this setting, we compared the long-term outcomes of URD-SCT using PBSC and bone marrow (BM) and studied the role of low-dose rabbit ATG in the prophylaxis of GVHD. Methods Between March 2004 and April 2012, 115 adult patients with AML underwent myeloablative (n=87) or reduced-intensity (n=28) conditioning HLA-matched URD-SCT with PBSC (n=70) or BM (n=45) grafts. All patients received tacrolimus and short-course methotrexate for GVHD prophylaxis. Low-dose rabbit ATG (Thymoglobuline®, 1.25 mg/kg for 2 days) was added only to the patients who received URD-SCT with PBSC grafts. The median follow-up of survivors was 44 months (range, 2-100) for PBSC transplants and 54 months (range, 8-105) for BM transplants (P=0.01). Results Baseline characteristics were not significantly different between the two groups except for total-body irradiation conditioning regimen (72.9% vs. 91.1%; P=0.02). PBSC transplants showed faster recovery of neutrophil (11 days vs. 13 days; P=0.03) and platelet (12 days vs. 18 days; P=0.01) counts than BM transplants. No difference was observed in the cumulative incidence of acute GVHD (grade ≥2) at 100 days (54.3% vs. 64.4%; P=0.38) and chronic GVHD at 4 years (61.4% vs. 60.0%; P=0.88) between the two groups. In spite of adding low-dose rabbit ATG, PBSC transplants did not show higher incidence of relapse compared to that of BM transplants (30.8% vs. 31.2%; P=0.53). Other transplant outcomes including non-relapse mortality (13.5% vs. 6.9%; P=0.24), disease-free survival (55.7% vs. 61.9%; P=0.80), and overall survival (63.3% vs. 63.2%; P=0.59) were comparable between the two groups. In multivariate analysis, graft source had no impact on transplantation outcomes. Regardless of graft source, transplants in ≥CR2 had higher relapse risk (hazard ratio, 2.45; 95 % CI, 1.04-5.76; P=0.04), poorer disease-free survival (hazard ratio, 2.68, 95% CI, 1.29-5.56; P=0.01) and overall survival (hazard ratio, 2.59; 95% CI, 1.20-5.59; P=0.02). Conclusion Adding low-dose rabbit ATG to the patients who received URD-SCT with PBSC may lower the incidence of acute and chronic GVHD comparably to that of URD-SCT with BM without increasing the incidence of relapse. Disclosures: No relevant conflicts of interest to declare.

Core-binding factor (CBF)-positive acute myeloid leukemia (AML) is regarded as a favorable group with good complete remission (CR) rate after induction chemotherapy and is generally treated by repeated high-dose cytarabine consolidation or autologous hematopoietic stem cell transplantation (auto-HSCT). However, emerging molecular studies have recently identified the unfavorable CBF-AML subgroup which should be treated by further intensified treatments. This single center retrospective study enrolled 264 adult CBF-AML patients from 2002 to 2011. Except 15 patients, 217 patients were treated by intensive induction chemotherapy and 32 were treated by reduced intensity treatment. After CR achievement, patients with available donor were treated by allogeneic (allo)-HSCT and the rest were treated by auto-HSCT or chemotherapy alone. We evaluated 206 patients who achieved CR after intensive chemotherapy regarding survival outcomes according to post-remission therapies and prognostic factors which affected the outcomes. The factors included cytogenetic study and subgroup analysis with additional chromosomes and normal karyotype (NK) mosaicism, c-kit mutation, minimal residual disease (MRD) qPCR level, BAALC and WT1 expression. We achieved CR in 94.9% with intensive chemotherapy and 115 patients went on allo-HSCT and 72 were treated by auto-HSCT. There were no significant OS differences between CBF¥â/MYH11 and RUNX1/RUNX1T1 (p=0.173), and auto-HSCT showed favorable EFS (p=0.038) compared to allo-HSCT and chemotherapy alone. For cytogenetic analysis, inv(16) or t(16;16) with NK mosaicism showed the most favorable OS compared to t(8;21) with additional chromosome (¡Ã2) which showed the worst OS. c-kit mutation was a poor prognostic factor with lower reduction rate of post-induction MRD qPCR, however the effect was not definite after HSCT. For HSCT patients, we analyzed post-HSCT MRD qPCR and WT1 expression level. We found that undetected level of post-HSCT MRD qPCR and lower level of WT1 expression ( For CBF-AML, the role of auto-HSCT and allo-HSCT for selected patients should be re-evaluated by large prospective studies and the values like post-treatment MRD qPCR and WT1 expression level can be used for prediction of patients who might relapse with higher probability. Disclosures: No relevant conflicts of interest to declare.

Abstract 2040 Comparable survival after 8/8-matched unrelated donor (URD) transplantation with HLA-matched siblings (MSD) has been reported in AML from a few multicenter studies. However, the role of 8/8-matched URD in acute myeloid leukemia (AML) with first complete remission (CR1) is uncertain because they applied various methods for HLA typing, such as low or intermediate resolution or partly high resolution (HR) typing, and/or included various disease status at transplantation. Additionally, there have been few studies comparing the clinical outcomes of 7/8-matched URD with current standard donors, such as MSD or 8/8-matched URD, particularly in AML, as a single disease. According to the risk-adapted treatment strategy, AML CR1 with intermediate or adverse cytogenetics received allogenetic transplantation as a post-remission treatment, if MSD or 8/8-matched URD was available. Patients with no available donor received 7/8-matched URD or autologous transplantation (only intermediate cytogenetics). Among 567 consecutive adult patients with AML who underwent transplantation between January 2002 and December 2009, in order to investigate the role of URD type in AML CR1, we assessed the transplantation outcomes of 8/8-matched URD (n=59) or 7/8-matched URD (n=36) classified by HR HLA typing, compared to MSD (n=165). Only intermediate or adverse cytogenetics was included, and we defined high-risk group as having one of the poor risk features, including adverse cytogenetics, hyperleukocytosis at diagnosis (over 100×109/L), older age over 60 years, or AML with myelodysplasia-related changes. In all, multivariate analyses showed that 8/8-matched URD had comparable 5-year disease-free survival (DFS; HR, 0.94; P=0.803), relapse (HR, 1.03; P=0.935), and non-relapse mortality (NRM; HR, 0.62; P=0.294) to MSD, while 7/8-matched URD had higher relapse (HR, 1.95; P=0.034) and a lower trend for DFS (HR, 1.47; P=0.154) than MSD without the difference in NRM (HR, 0.61; P=0.390). The equivalent outcomes of 8/8-matched URD were consistent irrespective of risk groups (high or standard). Particularly, only in standard-risk group, 7/8-matched URD (n=18) failed to show any benefit compared to concurrently performed autologous transplantation (n=67), contrasting to the superior survival of 8/8-matched URD (n=32) as well as MSD (n=108). In conclusion, the equivalent outcomes between MSD and 8/8-matched URD, irrespective of risk-group in AML CR1, suggest that 8/8-matched URD is useful for standard-risk as well as high-risk group of AML CR1, when lacking of MSD. On the other hand, the inferior outcome of 7/8-matched URD raise the necessity of trials comparing with other alternative graft sources, such as umbilical cord bloods or haploidentical family donors, particularly in AML with high-risk group. Disclosures: No relevant conflicts of interest to declare.

Abstract 1393 Background: Numerous molecular prognostic markers, in addition to specific chromosomal aberrations, have been identified to confer disease pathogenesis and survival outcomes in patients with adult acute myeloid leukemia (AML). Many efforts have been made to identify genetic mutations (e.g., c-kit, FLT3-ITD/TKD, NPM1, WT1, MLL-PTD) and modulated gene expression levels (e.g., BAALC and WT1) that can be used to predict outcomes in patients with cytogenetically normal AML (CN-AML). However, few data associated with core-binding factor AML (CBF-AML) and BAALC or WT1 expressions have been reported, and a consecutive analysis of BAALC and WT1 from diagnosis to hematopoietic stem cell transplantation (HSCT) has not yet been reported. We analyzed serial BAALC and WT1 data in patients with CN-AML and CBF-AML using the real-time quantitative polymerase chain reaction method. Methods: In this single center retrospective study, 1008 newly diagnosed patients with AML (age, 15–85 years; median 45.2 years) with variable karyotypes were initially enrolled from January 2005 to December 2010. Ultimately, we analyzed 335 patients with CN-AML and 156 with CBF-AML. Patients that underwent conservative treatment were excluded. Among 491 patients, we identified FLT3-ITD results in 316 patients (positive in 56 and negative in 260) and NPM1 results in 202 patients (positive in 50 for CN-AML only), and obtained BAALC and WT1 results at the initial diagnosis in 177 patients (126 in CN-AML and 51 in CBF-AML) since we started these laboratory examinations in 2008. In 126 of the patients with CN-AML, 68 underwent HSCT and 58 were treated with chemotherapy alone. In the CBF-AML group, 42 were treated with HSCT and 9 were treated with chemotherapy alone. We analyzed BAALC and WT1 serial data at the initial diagnosis, after the first cycle of induction chemotherapy, and before and after HSCT. An additional analysis included the decreased ratio in the logarithm between diagnosis, pre-HSCT, or post-HSCT. Overall survival (OS) and relapse free survival (RFS) were associated with BAALC and WT1 expression levels along with the treatment timeline, and concomitantly with FLT3, NPM1, and c-kit mutations. Survival and other clinical correlates and prognostic relevance of mutations in patients with CN-AML and CBF-AML were evaluated using the log-rank test, Cox proportional hazard model, and chi-square analyses. Results: In both the CN- and CBF-AML groups, BAALC and WT1 levels at the initial diagnosis had no definite influence on OS when patients were treated with HSCT. In patients with CN-AML, only the chemotherapy-treated group with higher BAALC expression at diagnosis showed poor remission status (p = 0.008) and inferior OS (p = 0.013). Higher BAALC expression at diagnosis resulted in inferior OS in patients with CN-AML and the NPM1 (n = 7 vs. 38, p = 0.002) and FLT3-ITD mutations (n = 14 vs. 19, p = 0.052) in each group, as well as those with both mutations (n = 4 vs. 15, p = 0.000). In contrast, higher WT1 expression at diagnosis resulted in inferior OS in patients with CN-AML without the NPM1 (n = 91, p = 0.022) and FLT3-ITD (n = 92, p = 0.012) mutations in each group, as well as without both mutations (n = 69, p = 0.092). Higher pre-HSCT WT1 expression also resulted in inferior OS (p = 0.002) and RFS (p = 0.015) after HSCT in patients with CN-AML. Pre-HSCT BAALC expression levels and the decrease in the BAALC ratio before HSCT was not significant, but the decrease in the WT1 ratio over 1 logarithm prior to HSCT resulted in superior OS (p = 0.001) and RFS (p = 0.002) in patients with CN-AML. In patients with CBF-AML, the c-kit mutation-positive group showed inferior OS (p = 0.044), and their mean BAALC expression level was exclusively higher than that of other karyotypes (73.4 vs. 19.8, p = 0.000). However, only higher BAALC expression levels at diagnosis were associated with an increased relapse rate and shortened RFS after HSCT (p = 0.023) in our cohort. Other BAALC and WT1 expression level parameters were not significant in patients with CBF-AML. Conclusion: The higher pre-HSCT WT1 expression and a decreased WT1 ratio before HSCT in patients with CN-AML, and higher BAALC expression at diagnosis in patients with CBF-AML resulted in significant changes in OS and RFS after HSCT. Therefore, the impact of combined molecular marker analysis on outcomes of allogeneic HSCT for AML should be considered intensively in order to produce a more defined HSCT plan. Disclosures: No relevant conflicts of interest to declare.