Abstract: 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 & lt;0.001). However, age, sex, disease status pre-transplant, HCT-CI, time from SCT1 to relapse, time from post-transplant relapse to SCT2, FLT3-ITD mutation status and cytogenetic risk distribution did not differ between each group. 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 & lt;0.001 for both). Cumulative incidence of acute and chronic GVHD were analyzed as follows; 39% and 42% for 1-year acute GVHD (p=0.82) and 43% and 11% for 2-year chronic GVHD (p=0.037) in HIT and CBT. In multivariate analysis, acute GVHD ≥ grade 2 after SCT1 (HR for OS 2.68, p=0.023; HR for DFS 2.49, p=0.036) and cytogenetic risk at diagnosis (HR for OS 2.07, p=0.018; HR for DFS 2.02, p=0.019) were significantly associated with worse outcomes. Hemorrhagic cystitis occurred more frequently in HIT patients than CBT group (32.3% vs 5.3%, p=0.035), while there were no significant differences between incidences of CMV DNAemia, CMV disease, thrombotic microangiopathy and sinusoidal obstructive syndrome. In subgroup analysis for patients relapsed after first allogeneic SCT1 only (18 patients in HIT and CBT group each), trend towards better outcomes in HIT than CBT were present, similar to those of all patients; 38% and 25% for 2-year OS (p=0.095), 39% and 10% for 2-year DFS (p=0.10), 22% and 51% for 2-year NRM (p=0.11) and 40% and 39% for 2-year CIR (p=0.90). 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.

Abstract: 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.

Abstract: 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 〈 0.001), and a value less than 22% was a relevant cut-off for diagnosing HLH. Additionally, lower NK-cytotoxicity showed inferior 2-year overall survival in the non-malignancy subgroup (72.2% vs. 88.8%, p=0.038). Multivariate analysis showed that low NK-cytotoxicity, splenomegaly, and marrow hemophagocytosis were independent diagnostic parameters for HLH, and low NK-cytotoxicity and EBV-association were related with poor survival outcomes in non-malignant febrile diseases. 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.

Abstract: 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.

Abstract: 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 & lt;0.001) and TRM (HR 2.461, 95% CI, 1.233-4.913, p=0.011 and HR 3.814, 95% CI, 1.766-8.237, p & lt;0.001). We reconfirmed the prognostic value of preexisting survival prediction models, Wheatley index scores, and web-based AML scores, contrasting to the lack of significance of Ferrara criteria. The addition of SPPB/SGDS-K or gait (or sit-and-stand) speed/SGDS-K improved the predictability of the Wheatley index and web-based AML scores with 69% and 90% relative increases in predictive power for survival, respectively. 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.

Abstract: 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.