Busulfan, Cyclophosphamide and Melphalan As Conditioning Regimen for Pediatric Patients with AML in 1st or 2nd CR: A Retrospective Analysis from the AIEOP HSCT Registry

Abstract Allogeneic stem cell transplantation (HSCT) is largely adopted as post-remissional therapy in children with acute myeloid leukemia (AML) in first complete remission (CR1) but with high-risk characteristics (including high-risk cytogenetics or high levels of minimal residual disease at the end of induction therapy) or to rescue patients reaching CR2 after a previous relapse. Busulfan-based regimens represent the standard of care for these patients in association with alkylating agents. One of the most frequent drugs combination used in Europe in pediatric patients is Busulfan, Cyclophosphamide and Melphan (BuCyMel), which provide a potent anti-leukemic effect, despite remarkable extramedullary toxicities, especially in adolescents. We aimed at analyzing the results of children with AML receiving BuCyMel and reported to the AIEOP registry from 2008 to 2015. A total of 182 patients were reported by 15 transplant centers. Median age at HSCT was 9 years (range 0.3-18); 100 patients (55%) were male. Disease status at HSCT was CR1 in 159 (88%) patients and CR2 in the remaining 23 (12%). All patients received the same myeloablative conditioning regimen with BuCyMel and GVHD prophylaxis was mainly based on calcineurin inhibitors, with the addition of methotrexate in unrelated donors recipients. In vivo T-cell depletion/modulation with ATG was used in 90 cases (49.5%). In almost all cases, pharmacokinetics monitoring of Busulfan was performed, with the drug dosage adjusted according to the systemic exposure evaluated after the first dose. Donor type was an HLA-matched family donor (MFD) in 82 (45%) patients and an unrelated donor (UD) in 100 (55%); 154 (85%) patients received bone marrow (BM) as stem cell source, while the remaining patients (15%) were transplanted with peripheral blood stem cells (PBSCs). Median follow up for surviving patients was 39 months (range 1-111). All patients achieved neutrophil engraftment. The cumulative incidence (CI) of grade II-IV and grade III-IV aGVHD was 35% (95%CI 28-42) and 11% (95% CI 7-16), respectively. The CI of aGVHD was not different according to the type of donor, being 37% (95%CI 28-50) and 32% (95%CI 24-46) in MFD and UD, respectively (p=0.38). The CI of chronic GVHD at 3 years was 17% (95%CI 12-24), while that of extensive cGVHD was 6% (95%CI 3-10). No difference was found in the CI of CGVHD according to the donor employed (MFD 15% and UD 19%, p=0.49). Overall, the CI of relapse and non-relapse mortality (NRM) at 3 years was 18% (95%CI 12-26) and 15% (95%CI 10-22), respectively. The CI of relapse and NRM was significantly different according to age at HSCT (using 12 years as cut-off): (Relapse age<12y: 21% (95%CI 15-32) and age>12y: 11% (95%CI 3-32), (p=0.003); NRM age<12y: 10% (95%CI 5-20) and age>12y: 24% (95%CI 15-37), (p=0.005). According to disease status at HSCT the CI of relapse and NRM were as follows: Relapse: CR1: 18% (95%CI 18-26), CR2 15% (95%CI 5-41) p=0.90) and NRM CR1: 14% (95%CI 9-21), CR2 19% (95%CI 8-46) p=0.38). Also, there was no difference in relapse and NRM by donor type, relapse: MFD 16% (95%CI 9-28), UD 19% (95%CI 11-32) p=0.38) NRM: MFD 19% (95%CI 11-34), UD 11% (95%CI 7-20) p=0.62). Causes of deaths were disease recurrence (39%), infections (27%), and GVHD (12%). Three- years overall survival (OS) and disease-free survival (DFS) were 74% (95%CI 67-81) and 68% (95%CI 60-70). DFS was 70% (95%CI 60-77) and 67% (95%CI 47-87) for patients transplanted in CR1 and CR2 respectively, (p=0.39); and was 70% (95%CI 59-81) and 65% (95%CI 53-78), p=0.77, for UD and MFD HSCT recipients, respectively. In conclusion, our results confirm the efficacy of BuCyMel in preventing relapse in a large series of pediatric patients affected by AML in CR1 and CR2. Adolescents represent a population of more fragile patients at risk of developing transplant-related fatalities. Optimization of toxicity profile and supportive care could further improve outcomes. Prospective randomized clinical trials are warranted to assess the best conditioning regimen for children and adolescents with AML. Disclosures Zecca: Chimerix: Honoraria. Locatelli:Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

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Comparable Outcomes After Sibling and Matched Unrelated Donor Allogeneic Hematopoietic Cell Transplantations (HCT) In Adult Acute Lymphoblatic Leukemia (ALL) With First Complete Remission (CR)

Blood ◽

10.1182/blood.v122.21.2142.2142 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2142-2142

Author(s):

Betul Oran ◽

Michelle Poon ◽

Julianne Chen ◽

Gabriela Rondon ◽

Sairah Ahmed ◽

...

Keyword(s):

Overall Survival ◽

Stem Cell ◽

Board Of Directors ◽

Disease Status ◽

Unrelated Donor ◽

Matched Unrelated Donor ◽

Advisory Committees ◽

Stem Cell Source ◽

Cell Source ◽

Donor Type

Abstract A landmark study from Medical Research Council/Eastern Cooperative Oncology Group showed improved survival (∼53%) for patients allocated to sibling HCT versus either consolidation/maintenance chemotherapy or autologous HCT. Matched unrelated donors (MUD) are an option for patients without a SIB available and we retrospectively analyzed disease outcomes after SIB and MUD in adult ALL patients. Between 2001and 2012, 204 adult ALL patients with a median age of 36 years (range, 18-64) were transplanted with a SIB (n=112) or 8/8 MUD (n=92). Disease status at HCT was first or second complete remission and beyond (CR1, n=113, 55.5% and CR2+, n=91, 44.5%). Conditioning was myeloablative in 177 (86.8%) and reduced intensity (RIC) in 27 patients (13.2%). All but 2 patients received graft versus host disease (GVHD) immunosuppression with tacrolimus and methotrexate. Patient and disease characteristics including age, sex, histological subtypes and high risk disease features (WBC and cytogenetic classification at diagnosis), disease status at HCT and conditioning intensity were similar between SIB and MUD recipients. As expected, MUD patients had bone marrow (BM) as the stem cell source more commonly than SIB (69.6% vs. 7.1, p<0.001). The median follow-up of 96 survivors was 36 months. The univariate point estimates at the stated timepoints and multivariate outcomes are summarized in the Table1 and 2.Table1The summary outcomesSIB (%)MUD (%)PNeutrophil recovery at day 4296.497.80.6Platelet recovery at day 1009281.50.03Grade II-IV aGVHD30.248.30.0093 year TRM in CR124.628.70.63 year TRM in CR2+21.023.10.83 year relapse incidence in CR124.420.60.63 year relapse incidence in CR2+49.939.60.33 year OS in CR155.955.60.83 year OS in CR2+33.137.90.8Table 2Multivariate results for OS*HR95%CIPCR1RefCR21.71.1-2.50.01Age <35RefAge>=351.71.1-2.60.01*Adjusted for cytogenetics and WBC at diagnosis, donor type and conditioning intensity.Figure 1Overall survival by disease status and donor typeFigure 1. Overall survival by disease status and donor type In summary, hematopoietic transplantation using a MUD was associated with slower platelet recovery which could be due to more common use of BM as the stem cell source. Acute GVHD incidence was also higher with MUD transplants but OS was comparable between donor types, even when patients were transplanted in CR1. Thus, in the absence of a SIB donor, a matched unrelated donor is an acceptable donor source for HCT with comparable overall survival. Disclosures: Qazilbash: Celgene: Membership on an entity’s Board of Directors or advisory committees Other; Millenium: Membership on an entity’s Board of Directors or advisory committees, Membership on an entity’s Board of Directors or advisory committees Other.

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Effectiveness of Reduced Toxicity Conditioning Regimen with Intravenous Busulfan Plus Pentostatin (BUPENT) in Patients Older Than 50 Years with Advanced Hematologic Malignancies.

Blood ◽

10.1182/blood.v114.22.3331.3331 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3331-3331

Author(s):

Tulio E. Rodriguez ◽

Mala Parthasarathy ◽

Scott E. Smith ◽

David H. Vesole ◽

Zachary M. Earley ◽

...

Keyword(s):

Overall Survival ◽

Stem Cell ◽

High Risk ◽

Stem Cell Transplantation ◽

Board Of Directors ◽

Graft Failure ◽

Conditioning Regimen ◽

Advisory Committees ◽

Reduced Toxicity

Abstract Abstract 3331 Poster Board III-219 Introduction Current data suggests that recipient age above 50 is associated with an inferior outcome after myeloablative allogeneic stem cell transplantation (SCT). Overall survival (OS) of 31%, and transplant related mortality (TRM) of 17% at 100 days have been reported in this population (Ditchkowski, et al 2005; Yanada, et al. 2004). Encouraging results are observed with non-myeloablative conditioning regimens. However, for patients with a high relapse risk, this approach may not be sufficient to achieve long term disease control. In these cases, a reduced toxicity, yet ablative stem cell transplantation (RT-SCT) may give adequate time to the transplanted cells to mature and mount an immune-mediated antitumor response. This study evaluated the outcome after RT-SCT using a conditioning regimen consisting of intravenous busulfan (Bu) and pentostatin (Pent). Methods Consented adult patients up to 70 years with a fully-matched related (MRD) or unrelated donor (MUD) were screened for enrollment. Conditioning consisted of Bu 1.6 mg/kg every 12 hours days -7 to -4, and Pent 4 mg/m2 on day -3 and -2 prior to stem cell infusion on day 0. GVHD prophylaxis was methotrexate 10 mg/m2 on day 1, and 5 mg/m2 on days 3, and 6. Tacrolimus was started on day -2, and then tapered over 1 month after day +100. Characteristics Twenty six patients were analyzed. Male to female ratio was 1:1. Stem cell source was from MRD in 15 patients and MUD in 11. Median age was 62, with 92% of patients being older than 50 years. Indications for treatment were AML (35%), MDS (42%), Refractory CLL (23%), Relapsed NHL (12%), and Philadelphia (+) ALL (4%). All AML patients were high risk either due to poor cytogenetic, transformation, or relapse and only two of them were transplanted in first complete remission. MDS patients were RAEB (36%), secondary MDS (36%), or multilineage dysplasia (18%). Two patients had prior autologous transplants. Results No graft failure was observed. All patients achieved neutrophil (NEU) engraftment. Two patients expired prior to platelet (PLT) engraftment. Median engraftment days for NEU and PLT were 13 days. At a median follow up of 25 months, the OS and progression free survival for the entire group was 40% and 38% respectively. The OS in the MRD group was 58%. TRM at 100 days was seen in one patient (4%) due to veno-occlusive disease (VOD). Limited chronic GVHD was the most common observed toxicity (54%), followed by diarrhea (30%) and mucositis (23%). Mucositis was mainly grade 1 (8%) and grade 2 (8%). No grade 3 mucositis was observed. There was only one case of VOD and one case of acute GVHD. Conclusion To our knowledge, this is the first report of a RT-SCT using BuPent. This study demonstrates the efficacy of the regimen in patients older than 50 years. No graft failure was observed and the regimen related toxicity was acceptable in this high-risk population. The overall survival of 40% at a median follow up of 25 months compares favorably with prior reports of myeloablative allogeneic stem cell transplatation in patients older than 50 years. This regimen provides an exciting opportunity to extend the benefits of allogenic transplant to an older population, and warrants replication with larger controlled trials. Disclosures Rodriguez: Otsuka: Membership on an entity's Board of Directors or advisory committees, Research Funding. Vesole:Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Speakers Bureau; Millenium: Speakers Bureau; Centocor Ortho Biotech: Speakers Bureau.

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Phase I/I Clinical Trial for the Evaluation of Bortezomib within the Reduced Intensity Conditioning Regimen (RIC) and Post-Allogeneic Transplantation As Gvhd Prophylaxis Among High-Risk Myeloma Patients. EudraCT: 2005–004858-27

Blood ◽

10.1182/blood.v118.21.3025.3025 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3025-3025

Author(s):

Jose Antonio Perez-Simón ◽

Teresa Caballero-Velazquez ◽

Cristina Encinas ◽

Cristina Castilla-Llorente ◽

Rodrigo Martino ◽

...

Keyword(s):

High Risk ◽

Board Of Directors ◽

Conditioning Regimen ◽

Disease Status ◽

Allogeneic Transplantation ◽

Reduced Intensity Conditioning ◽

Advisory Committees ◽

Gvhd Prophylaxis ◽

Reduced Intensity Conditioning Regimen ◽

Reduced Intensity

Abstract Abstract 3025 Introduction: Although allogeneic stem cell transplantation (allo-SCT) is the only curative treatment for MM, it is associated to a high morbility and mortality. Moreover, relapses are common after allo-RIC. Accordingly, new strategies are required to reduce both the risk of relapse and the toxicity of the procedure. As we have previously demonstrated, Bz induces a selective depletion of alloreactive T-cells and has immunomodulatory properties which might be of potential benefit for GVHD control. The primary end point of this study was to evaluate the efficacy of allo-RIC in terms of response when Bz was added as part of a reduced intensity conditioning prior to allo-SCT. Secondary end points included incidence of GVHD and analysis of the toxicity of the procedure when Bz is also administered post-infussion as part of the GVHD prophylaxis. Method: Prior to allo-RIC, patients received two cycles of Bz plus dexamethasone. Conditioning consisted of fludarabine (30 mg/m2 intravenously on days -9 to -5) and melphalan (70 mg/m2 intravenously on days -4, -3) plus Bz 1, 3mg/m2 on day - 11 and -2. GVHD prophylaxis included cyclosporine (CsA) and methotrexate for the first 9 patients and CsA plus MTX and Bz on days +3 and +7 for the remaining 7 patients. From day +50 post allo-RIC 7 cycles of Bz (+1, +8, +15) were administered, the first two cycles every 28 days and the rest every 56. Results: 16 patients from the Twenty-one initially enrolled, were evaluable. All 16 patients had received at least 2 lines of therapy including autologous-SCT. Disease status was CR or nCR in 4 patients, 9 had PR and the remaining 3 patients had relapsed / progressive disease. 15 patients maintained or improved status at transplant including all × patients with active disease at transplant. Eight patients (50%) relapsed, four with extramedullary involvement. No patient developed grade 4 aGVHD.Grades 2–3 aGVHD occurred in 6 patients (37%). Interestingly, two out of the nine (29%) patients who received Bz on days +3 and 7 developed grades 2–3 acute GVHD as compared to four of the nine (44%) who did not receive it. In terms of toxicity, one patient did not achieve platelet engraftment and 2 patients developed peripheral neuropathy requiring treatment withdrawal. 8 patients died, four of them due to relapse (MRT: 25%). With a median follow-up of 457 days overall survival was 46%. Conclusions: The current trial is the first evaluating the efficacy and safety of Bz as part of a reduced intensity conditioning regimen among patients with high risk MM undergoing allogeneic transplantation. Regarding the efficacy of the procedure all but one patient improved disease status post-alloRIC although relapse rate was still high in this heavily pretreated population. In addition, Bz post-alloSCT is well tolerated and may decrease the incidence of GVHD. Disclosures: Perez-Simón: Janssen-Cilag: Patents & Royalties. Off Label Use: This study evaluates the efficacy of Bortezomib as part of a reduced intensity conditioning regimen among patients with high risk MM undergoing allogeneic transplantation. Rosiñol:Celgene: Honoraria; Janssen: Honoraria. San Miguel:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees; Millennium: Membership on an entity's Board of Directors or advisory committees.

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Fludarabine and Melphalan Compared with Reduced Doses of Busulfan and Flurabine Improves Transplant Outcomes in Older MDS Patients

Blood ◽

10.1182/blood-2019-121970 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 253-253

Author(s):

Betul Oran ◽

Kwang Woo Ahn ◽

Caitrin Fretham ◽

Mithun Vinod Shah ◽

Ryotaro Nakamura ◽

...

Keyword(s):

Total Dose ◽

Board Of Directors ◽

Research Funding ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Disease Free Survival ◽

Sensitivity Analyses ◽

Unrelated Donor ◽

Advisory Committees ◽

Hematopoietic Stem

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only potentially curative therapy in eligible patients with myelodysplastic syndromes (MDS). Reduced-intensity conditioning (RIC) regimens that have been developed to extend HSCT to older patients resulted in encouraging outcomes. However, several retrospective studies have raised concerns about disease control when RIC is used in MDS and the ideal conditioning regimen has not yet been found. In this study, we aimed to compare two most commonly used RIC regimens; intravenous use of fludarabine with busulfan (FluBu) and fludarabine with melphalan (FluMel). Study population: Through the CIBMTR, after excluding patients with ex-vivo T cell depletion, we identified 1045 MDS patients aged ≥ 60 years and underwent first HSCT with matched related or matched (8/8) unrelated donor (MRD and MUD) using RIC between 2007-2016. RIC was defined via CIBMTR criteria as a regimen that incorporated an IV busulfan (BU) total dose ≤ 7.2 mg/kg or low-dose melphalan (MEL) total dose ≤ 150 mg/m2. By that, we identified 697 MDS patients who received FluBu (BU 6.4 mg/kg: 87%, BU 3.2 mg/kg: 13%) and 448 receiving FluMel (MEL 140 mg/m2: 80%, MEL 100 mg/m2: 20%). Results: The two groups, FluBu and FluMel, were comparable for disease and transplant related characteristics except the more frequent use of ATG or Campath in FluBu group (39% vs. 31%). The median age was 67 in both groups, and 26% and 19% of FluBu and FluMel groups were aged ³70, respectively. Hematopoietic comorbidity index (HCT-CI) was ³3 in 61% and 59% of FluBu and FluMel groups and MDS risk score by CIBMTR at HCT was high/very high in 34% in both groups. FluMel was associated with a reduced relapse incidence (RI) after HSCT compared with FluBu as presented in Table 1 and Table 2. Adjusted RI at 1-year was 43% with FluBu and 25% with FluMel (p=<0.0001). On the other hand, transplant related mortality (TRM) was higher with FluMel compared with FluBu (27% vs. 15%, p=<0.0001). The difference persisted at 2- and 3-years after HSCT as presented in the figure. Since the magnitude of improvement in RI was greater with FluMel than the improvement in TRM with FluBu, disease-free survival (DFS) was improved at 1-year and beyond with FluMel compared with FluBu (48% vs. 41% at 1-year, p=0.030, and 38% vs 28% at 3-years, p=0.0030). These outcome differences remained significant when sensitivity analyses were performed excluding patients who received RIC with either BU 3.2 mg/kg or Mel 100 mg/m2. FluMel, did not lead to higher incidence of severe grade 3-4 aGvHD (HR=1.2, 95%CI, 0.9-1.6, p=0.3) or chronic GvHD (HR=0.9, 95%CI=0.7-1.06, p=0.2). However, grade 2-4 aGVHD was observed more often with FluMel than FluBu (HR=1.3, 95%CI, 1.1-1.6, p=0.006). This led to inferior outcomes of GRFS within the first 2 months with FluMel (HR=1.9, HR=1.4-2.6, p<0.001) but superior outcomes of GRFS beyond 2 months with FluMel compared with FluBu (HR=0.7, 95%CI=0.6-0.8, p<0.001). Conclusion: Our results suggest that between the two most commonly used RIC regimens in older MDS patients, FluMel was associated with superior DFS and overall survival compared with FluBu due to reduced RI despite higher TRM. Disclosures Oran: AROG pharmaceuticals: Research Funding; Astex pharmaceuticals: Research Funding. Nakamura:Kirin Kyowa: Other: support for an academic seminar in a university in Japan; Alexion: Other: support to a lecture at a Japan Society of Transfusion/Cellular Therapy meeting ; Celgene: Other: support for an academic seminar in a university in Japan; Merck: Membership on an entity's Board of Directors or advisory committees. Scott:Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Alexion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Agios: Speakers Bureau. Popat:Jazz: Consultancy; Incyte: Research Funding; Bayer: Research Funding.

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Utilizing Organ-Sparing Marrow Irradiation to Condition Patients Prior to Allogeneic Hematopoietic Cell Transplant with High-Risk Hematologic Malignancies: Results of a Pilot Study

Blood ◽

10.1182/blood-2021-150948 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 2856-2856

Author(s):

Sumithira Vasu ◽

Meghan Kromer ◽

Qiuhong Zhao ◽

Hannah Choe ◽

Karilyn Larkin ◽

...

Keyword(s):

Overall Survival ◽

High Risk ◽

Board Of Directors ◽

Research Funding ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Cell Transplant ◽

Advisory Committees ◽

High Incidence ◽

Grade Ii

Abstract Background: Total body irradiation (TBI) has long been incorporated as part of the conditioning regimen prior to hematopoietic stem cell transplant (HSCT). While the myeloablative TBI conditioning is associated with a lower relapse rate in high risk diseases such as Acute Myeloid Leukemia (AML), Myelodysplastic Syndrome (MDS), and Acute Lymphoblastic Leukemia (ALL), it is also associated with substantial toxicities, and increased NRM so use of this regimen is limited to young patients with excellent performance status. In this study, we used a linac-based volumetric modulated arc therapy (VMAT) technique to deliver standard myeloablative radiation to high risk body sites while sparing radiation sensitive organs (Organ Sparing Marrow Targeted Irradiation, OSMI). We hypothesized that this technique would be feasible and safe in patients who are older or who have higher transplant specific comorbidity index (HCT-CI), typically ineligible for standard TBI conditioning. Methods: This is a single-arm prospective study. Patients from age 18-75 with high risk AML, MDS or ALL were eligible. There are 3 cohorts: (1) age 18-50 with HCT-CI of 3/4; (2) age 51-65 with HCT-CI of ≤ 3; and (3) age 66-75 with HCT-CI of ≤ 2. Patients receive OSMI to a total dose of 1200 cGy delivered twice daily for 6 fractions for a total of 7200 cGy. Clinical tumor volume includes total skeletal bone marrow and any sanctuary or high-risk areas. Graft-versus-host disease (GVHD) prophylaxis originally was tacrolimus and methotrexate. Given high incidence of bacterial infections related to mucositis, prophylaxis was changed to tacrolimus and sirolimus without methotrexate. All patients received Keratinocyte growth factor for prevention of mucositis. The primary objective was to assess feasibility and tolerability of OSMI based HSCT as defined by transplant-related mortality (TRM) at day 30 (D30) as well as rate of grade II/III organ toxicity (defined by Bearman Regimen-Related Toxicities Scale) attributable to conditioning occurring within 30 days. Results: Patient demographics for the 24 patients are shown in Table 1. Median age of recipients was 56.5 years. No graft failures were observed. The most common grade II or III Bearman toxicities include mucositis (grade 2: n=4), and diarrhea (grade 2: n=4). Clinical outcomes are shown in Figure 2. With a median follow-up of 3.3 years, overall survival (OS) and relapse-free survival (RFS) at 2 years was 78% and 74% respectively. Among the 5 patients who were not in complete remission at the time of transplant, 2-year OS and RFS rate was 40%. Incidence of Grades II-IV acute GVHD was 79% and Grades III-IV GVHD was 30%. Relapse incidence was 4% at 2 years. Incidence of Thrombotic microangiopathy by day 100 (TMA) as defined by Jodele's criteria was 17%. Incidence of chronic GVHD was 45% and severe chronic GVHD was 16%. One year non-relapse mortality was 22%, likely due to higher incidence of GVHD. Conclusions: Selected patients who are older or with higher HCT-CI, who are typically not candidates for standard TBI conditioning, were able to receive a radiation-based myeloablative conditioning regimen with 2 year overall survival rates of 78%. We observed a high incidence of TMA, possibly related to use of tacrolimus and sirolimus as GVHD prophylaxis, and a high incidence of Grade II-IV acute GVHD. Low incidence of relapse was observed. OSMI-based conditioning was feasible in this cohort with median age of 56 years and was associated with low rates of relapse and favorable 2 year overall survival. Figure 1 Figure 1. Disclosures Vasu: Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: travel support; Kiadis, Inc.: Research Funding; Omeros, Inc.: Membership on an entity's Board of Directors or advisory committees. Jaglowski: Novartis: Consultancy, Research Funding; Takeda: Consultancy; Juno: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding; CRISPR Therapeutics: Consultancy. Brammer: Seattle Genetics: Speakers Bureau; Celgene: Research Funding; Kymera Therapeutics: Consultancy. de Lima: Incyte: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotec: Research Funding.

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Dose-Reduced Conditioning Followed by Allogeneic Stem Cell Transplantation in Patients with Myelofibrosis. Results from a Multicenter Prospective Trial of the Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT).

Blood ◽

10.1182/blood.v110.11.683.683 ◽

2007 ◽

Vol 110 (11) ◽

pp. 683-683 ◽

Cited By ~ 5

Author(s):

Nicolaus Kroeger ◽

Ernst Holler ◽

Guido Kobbe ◽

Martin Bornhaeuser ◽

Rainer Schwerdtfeger ◽

...

Keyword(s):

Stem Cell ◽

High Risk ◽

Chronic Gvhd ◽

Prospective Trial ◽

Conditioning Regimen ◽

Working Party ◽

Unrelated Donor ◽

Jak2 Mutation ◽

Cytogenetic Abnormalities ◽

Excellent Outcome

Abstract The major limitation of allogeneic stem cell transplantatiopn (SCT) in patients (pts) with myelofibrosis is the high treatment related mortality. We performed a prospective multicenter trial of a dose-reduced conditioning regimen, consisting of busulfan (10 mg/kg orally or 8mg/kg i.v), fludarabine (180 mg/m2) and anti-thymocyte globulin (ATG Fresenius: 30–60 mg/kg) followed by allogeneic SCT in pts with myelofibrosis. From 2002 to 2006, 104 pts with a median age of 55 years (range: 32–68) andlow risk with constitutional symptoms (18%) or intermediate risk (n= 58%) and high risk (n=19%) were included. Cytogenetic abnormalities and JAK2 mutation were noted in 22% and 48%, respectively. Bone marrow histology showed advanced fibrosis (MF 2 and 3) in all pts. All but 3 pts received peripheral blood stem cells as graft source either from related (n=33) or unrelated donor (n=71). All but one (1%) pts showed leukocyte and platelet engraftment after a median of 18 and 21 days, respectively. The median duration of leukocyte aplasia was 9 days (range: 3–21). Acute GvHD grade II to IV occurred in 19% and severe aGvHD III/IV in 7%, while chronic GvHD was seen in 32% of the pts. Non-relapse mortality at 1 year was 19% (95% CI: 11–27%) and significantly lower for pts younger than 50 years of age (0% vs 27%, p=0.004) and for pts with low risk vs intermediate/high risk disease (0% vs 27%, p= 0.02). The cumulative incidence of relapse at 3 years was 29% (95%CI: 15–43%). The 3 year overall (OS) and event-free survival (EFS) was 70% (95% CI 60–80%) and 55% (95% CI 42–68%). Significant factors for improved 3 year OS and EFS were age less than 50 years (92% vs 62%, p=0.003 and 79% vs 46%, p= 0,004) and low vs intermediate/high risk (100% vs 62%, p=0.01 and 72% vs 48%, p= 0.02), while no impact on survival was seen for cytogenetic abnormalities, JAK2 mutation status and donor (related vs unrelated). These prospective multicenter study show excellent outcome of an busulafan/fludarabine based reduced conditioning regimen followed by allogeneic SCT in pts with myelofibrosis.

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Haploidentical Transplantation (HAPLO) with Post-Transplant High-Dose Cyclophosphamide for Graft Vs Host Disease (GVHD) Prevention in the Treatment of High Risk Hematological Neoplasms

Blood ◽

10.1182/blood.v120.21.4545.4545 ◽

2012 ◽

Vol 120 (21) ◽

pp. 4545-4545

Author(s):

Jorge Gayoso ◽

Mi Kwon ◽

David Serrano ◽

Pascual Balsalobre ◽

Javier Anguita ◽

...

Keyword(s):

High Risk ◽

Conflicts Of Interest ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Disease Status ◽

Allogeneic Transplantation ◽

High Dose ◽

Unrelated Donor ◽

Haploidentical Transplantation ◽

Gvhd Prophylaxis

Abstract Abstract 4545 Introduction: Allogeneic transplantation is the only curative option in the treatment of multiple high risk hematologic neoplasms. Only 25–30% of patients have an HLA identical sibling donor and searching for a compatible unrelated donor or cord blood renders satisfactory results in around 60–70%. Haploidentical transplantation (HAPLO) offers a therapeutic alternative to more than 95% of such patients with the advantages of quick availability, easy programming and a committed donor. Patients and Methods: We evaluate the results of HAPLO with a reduced intensity conditioning regimen (Fludarabine 30 mg/m2 ×5 days (-6 to -2), Cyclophosphamide 14,5 mg/kg ×2 days (-6 and -5), IV Busulfan 3,2 mg/kg × 1–3 days (BUX, days -4 to -2) employing high doses of Cyclophosphamide post graft infussion (50 mg/kg days +3 and +4) as GVHD prophylaxis together with standard doses of cyclosporine and mycophenolate from day +5. Results: From Dec-2007, we have done 26 HAPLO in 4 spanish centers. Median age was 38 years (16–57), 20 were male and all were in advanced phases of their diseases (12 Hodgkin′s, 6 AML, 3 ALL, 2 MM, 1 MDS, 1 MF y 1 NHL). Previous autologous HSCT has been employed in 13 and allogeneic HSCT in 6 (2 MURD and 4 UCB). Disease status at HAPLO was CR in 8, PR in 14 and refractory in 4. Bone marrow was used in 16 and unmodified peripheral blood in 10. The haploidentical donor was patient′s mother (8), father (3), siblings (11) or other relatives (4). BUX was used in 1 dose (15), 2 doses (8) or 3 doses (2) and TBI 200 cGy in 1 case. Mean neutrophils engraftment was achieved on day +18 (13–26) and platelets >50K on day +27 (17–150) in all but 2 cases of graft failure (7.7%) due to progression (MF) or relapse (M7-AML). Main toxicities were grade 1–2 mucositis in 50%, febrile neutropenia in 75% and CMV reactivations in 58% with a 100 days NRM of 3.8% (1/26, VOD and MOF) and 10% NRM at 6 months (2/20). Grade II-IV acute GVHD appeared in 10/23 patients at risk (43%) and grade III-IV in 4/23 (17%). Chronic GVHD affected to 4/15 (27%), being extensive in 1/15 (6.7%). With a median follow-up of 9 months (1–38), 13/22 (59%) are alive in CR, progression or relapse has ocurred in 6/24 (25%). Immune reconstitution seems fast and complete in those evaluated. Conclusions: HAPLO with high-dose cyclophosphamide as GVHD prophylaxis is a useful alternative in the treatment of high risk hematologic tumours, with low toxicity, acceptable GVHD incidence and severity, long lasting remissions, and fast immunological reconstitution. Disclosures: No relevant conflicts of interest to declare.

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Outcomes of Allogeneic Hematopoietic Cell Transplantation in Adults with Ph-like ALL

Blood ◽

10.1182/blood-2021-153125 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3955-3955

Author(s):

Ibrahim Aldoss ◽

Dongyun Yang ◽

Zhaohui Gu ◽

Vanina Tomazian ◽

Sally Mokhtari ◽

...

Keyword(s):

High Risk ◽

Board Of Directors ◽

Relapse Rate ◽

Research Funding ◽

Hematopoietic Cell Transplantation ◽

Conditioning Regimen ◽

Disease Status ◽

R Package ◽

Genetic Alterations ◽

Advisory Committees

Abstract Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) represents 20% of newly diagnosed adults with B cell ALL (B-ALL), with increased frequency in adults with Hispanic ethnicity. Ph-like ALL harbors a diverse range of genetic alterations with CRLF2-rearrangement/overexpression (CRLF2r) being the most common one. When treated with chemotherapy, Ph-like ALL is associated with inferior response, high relapse rate, and low overall survival (OS). Allogenic hematopoietic cell transplantation (alloHCT) is a well-established curative modality for adults with high-risk ALL. Considering that Ph-like ALL is a high-risk leukemia subtype, it is appealing to recommend alloHCT consolidation routinely for this entity in adults. However, large datasets describing alloHCT outcomes in patients with Ph-like ALL is lacking. In this study, we retrospectively analyzed archived DNA samples from 125 consecutive adult patients with Ph-negative ALL who underwent alloHCT in complete remission (CR) at our center between 2006 and 2020. Classification of Ph-like versus non-Ph-like was performed according to WHO 2017 classification using accumulative results from RNAseq, conventional cytogenetics, FISH, and whole genome array studies. A proprietary RNA sequencing assay covering 1,188 genomic regions from 235 genes was designed to detect all the clinically significant fusions and expressions for Ph-like ALLs. In addition, an algorithm employing the RNAseq data was developed to further aid in classification of Ph-like ALL. Boruta feature selection (R package "Boruta" version 7.0.0) was used to identify the most informative genes for prediction with an out-of-bag error of 9.62%. The following 24 genes were identified: CCND2, SOX11, PAX5, DENND3, RARA, MME, ID4, SH3BP5, HOXA9, CA6, MUC4, CYB5R2, CD97, EPOR, IL2RA, RAB29, PDGFRA, MLLT4, RHOA, JAK2, DNM2, ASXL1, BCL2A1, and KDR. The results were used to predict Ph-like status by a Random Forest model (R package "randomForest" version 4.6-14) that generates a probability/similarity score of Ph gene expression profile (Ph score). The testing samples with Ph score over 50% and without other subtype-defining lesions are defined as Ph-like. We identified Ph-like genetic alterations in 66 (53%) patients, of whom 42 (66%) were carrying CRLF2r and 24 (36%) were non-CRLF2r. Compared to non-Ph-like ALL (n=59), Ph-like ALL patients were younger (42 vs 36 years old, p=0.022), more frequently Hispanic (56% vs 83%, p=0.003), less frequently carried high-risk cytogenetics (39% vs 9%, p<0.001), more frequently induced with pediatric-inspired regimens (25% vs 61%, p=0.003) and more likely required >1 regimen to achieve their first complete remission (CR1; 30% vs 55%, p=0.025). However, we did not detect any significant difference between the two groups in disease status (CR1 vs. CD2/3; p=0.81) or minimal residual disease clearance at the time of HCT (negative vs. positive; p=0.17), donor type (match related/unrelated vs mismatch vs haplo vs cord blood; p=0.88), conditioning regimen intensity (myeloablative vs non-myeloablative/ reduced intensity; p=0.59), GVHD prophylaxis (tacrolimus/sirolimus-based vs PTCy-based; p=0.84), Karnofsky Performance Status (KPS; p=0.24) or HCT comorbidity index (0 vs 1-2 vs >2; p=0.42). With the median follow-up of 3.2 years, we observed similar 3-years leukemia-free survival (LFS) (40% vs 47%; p=0.95), OS (44% vs 54%; p=0.96), relapse rate (33% vs 34%; p=0.96) and non-relapse mortality (NRM) (27% vs 19%; p=0.92) between non-Ph-like and Ph-like ALL patients, respectively. (Figure) In multivariable analysis, disease status at the time of HCT (HR=2.63, 95% CI: 1.57-4.41; p<0.001), donor type (p=0.049) and KPS (HR=2.22, 95% CI: 1.05-4.69; p=0.038) influenced OS. LFS was significantly influenced by disease status (HR=2.35, 95% CI: 1.45-3.80); p<0.001) and conditioning regimen intensity (HR=1.84, 95% CI: 1.11-3.04; p=0.017). Relapse rate was associated with disease status (HR=2.06, 95%CI: 1.11-3.84; p=0.23) and conditioning regimen intensity (HR=1.97, 95% CI: 1.03-3.75; p=0.40). Only KPS (HR=6.56, 95% CI: 2.48-17.36; P<0.001) was associated with NRM. In conclusion, our data suggest that alloHCT consolidation results in favorable outcomes in adult patients with Ph-like ALL with comparable outcomes to non-Ph-like ALL. Our data support utilization of alloHCT for adults with Ph-like ALL in CR. Figure 1 Figure 1. Disclosures Al Malki: Neximmune: Consultancy; Rigel Pharma: Consultancy; Jazz Pharmaceuticals, Inc.: Consultancy; Hansa Biopharma: Consultancy; CareDx: Consultancy. Khaled: Omeros: Honoraria; Alexion: Honoraria, Speakers Bureau; Janssen: Current Employment; Astellas: Honoraria; Jazz: Honoraria. Ali: Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Speakers Bureau; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees. Aribi: Seagen: Consultancy. Mei: BMS: Research Funding; Epizyme: Research Funding; TG Therapeutics: Research Funding; EUSA: Honoraria; Janssen: Honoraria; Morphosys: Research Funding; Beigene: Research Funding. Koller: Novartis: Consultancy. Artz: Radiology Partners: Other: Spouse has equity interest in Radiology Partners, a private radiology physician practice. Stein: Amgen: Consultancy, Speakers Bureau; Celgene: Speakers Bureau; Stemline: Speakers Bureau. Marcucci: Abbvie: Other: Speaker and advisory scientific board meetings; Novartis: Other: Speaker and advisory scientific board meetings; Agios: Other: Speaker and advisory scientific board meetings. Forman: Lixte Biotechnology: Consultancy, Current holder of individual stocks in a privately-held company; Mustang Bio: Consultancy, Current holder of individual stocks in a privately-held company; Allogene: Consultancy. Pullarkat: AbbVie, Amgen, Genentech, Jazz Pharmaceuticals, Novartis, Pfizer, and Servier: Membership on an entity's Board of Directors or advisory committees; Amgen, Dova, and Novartis: Consultancy, Honoraria.

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Long-Term Outcome of Children with Acute Leukemia (AL) Given Alphabeta T and B-Cell Depleted HLA-Haploidentical Hematopoietic Stem Cell Transplantation (TBdepl-haploHSCT)

Blood ◽

10.1182/blood-2019-128416 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 799-799

Author(s):

Pietro Merli ◽

Daria Pagliara ◽

Mattia Algeri ◽

Federica Galaverna ◽

Giuseppina Li Pira ◽

...

Keyword(s):

Board Of Directors ◽

Cumulative Incidence ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Disease Status ◽

Advisory Committees ◽

Low Incidence ◽

Patient’S Outcome

Background: TBdepl-haploHSCT is a suitable option for children with AL in need of an allograft, lacking an HLA-compatible donor. We previously published promising results in a cohort of 80 children with AL, given this type of allograft (Locatelli et al., Blood 2017), demonstrating a low incidence of acute and chronic graft-versus-host disease (GvHD) and low non-relapse mortality (NRM), translating into a final outcome comparable to that of patients transplanted from an HLA-compatible donor. We present the long-term follow-up analysis of this study (NCT01810120), now including 134 patients, with a minimum observation time of 100 days after the allograft. Patients and methods: Between October 2010 and April 2019, 134 children with AL in morphological complete remission (CR) received TBdepl-haploHSCT from an HLA-partially matched relative (a parent in 97% of cases) at Ospedale Pediatrico Bambino Gesù in Rome, Italy. All patients were prepared to the allograft using a fully-myeloablative conditioning regimen including a combination of cytotoxic drugs and/or total body irradiation (TBI). Anti-T-lymphocyte globulin (ATLG) was used before transplantation (12 mg/kg total dose, from days -5 to day -3) to modulate bi-directional donor/recipient alloreactivity. Rituximab (200 mg/sqm) was administered on day -1 to prevent post-transplantation EBV-induced lymphoproliferative disorders (PTLD). No patient received any post-transplant GvHD prophylaxis. Results: Characteristics of patients enrolled in the study are shown in Table 1. Median follow-up of surviving patients is 60 months (range: 3 months - 8.7 years). Only 3 patients did not achieve engraftment (all affected by acute myeloid leukemia and who did not receive TBI during conditioning regimen); median time to neutrophil and platelet recovery was 13 (range 9-22) and 11 (range 8-23) days, respectively. Cumulative incidence of grade II-III acute GvHD was 16.5% (95% CI 9.9-22.6). One patient developed gut GvHD, while for all other patients skin was the sole organ involved; no case of grade IV GvHD was recorded. Eight out of the 123 patients at risk developed chronic GvHD, in all cases of limited severity, the cumulative incidence of this complication being 7.6% (95% CI 2.3-12.6). Six patients died for transplant-related complications (2 because of idiopathic pneumonitis and 1 each of disseminated adenovirus infection, cardiac insufficiency, combined CMV/rhinovirus pneumonia and sepsis from Pseudomonas aeruginosa), the 5-year cumulative incidence of NRM being 4.5% (95% CI, 1.8-9.0). Since 25 patients relapsed at a median time of 173 days (range 59-1012) after HSCT, the 5-year cumulative incidence of relapse is 21.1% (95% CI, 14.2-29.1). The 5-year probability of overall and leukemia-free survival (LFS) were 74.6 (95% CI 65.1 -71.9) and 74.4% (95% CI 65.4-81.4) (Figure 1A), respectively. Use of TBI during the preparative regimen, age at transplant above the median value (Figure 1B) and disease status at transplantation (CR1 and CR2, Figure 1C) were associated with better patient's outcome, because of a reduced incidence of relapse (Figure 1D for TBI). All these 3 factors remained statistically significant in multivariable analysis for LFS: hazard ratio (HR) for TBI was 0.16 (95% CI, 0.06- 0.37, p<0.001, HR for age at HSCT was 0.27 (95% CI, 0.11-0.65, p=0.003), while that for disease status was 0.49 (95% CI, 0.26-0.91, p=0.02), respectively. The 5-year GvHD/relapse-free survival was 69.9% (95% CI 60.8-77.3). The median CD3+ cell count on day +30, +90, +180 and +360 were 187, 215, 660 and 1260/mcl, respectively. Conclusions: These data confirm in a larger population and with a longer follow-up that TBdepl-haploHSCT is a safe and effective transplant option, being associated with a low risk of both NRM and acute/chronic GvHD, resulting into a 5-year LFS comparable or even better with that reported in studies using either an HLA-identical sibling or an unrelated volunteer as donor. In particular, the low incidence of chronic GvHD preserves a good quality of life in patients with long life-expectancy. Leukemia recurrence represents the main cause of treatment failure and strategies based either on the use of a titrated number of donor T cells transduced with a safety switch or ex-vivo depleted of the alloreactive component could further improve patient's outcome. Figure 1 Disclosures Merli: Novartis: Honoraria; Sobi: Consultancy; Amgen: Honoraria; Bellicum: Consultancy. Algeri:Miltenyi: Honoraria; Atara Biotherapeutics: Consultancy, Honoraria; Bluebird bio: Consultancy, Honoraria. Locatelli:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Miltenyi: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees.

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Profound Lymphopenia at the Time of ATG Administration Is Not Predictive of Survivals after Allotransplant Using Purine Analogue/Busulfan-Based Conditioning Regimen

Blood ◽

10.1182/blood-2019-122013 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1985-1985

Author(s):

Maxime Jullien ◽

Thierry Guillaume ◽

Pierre Peterlin ◽

Alice Garnier ◽

Amandine Le Bourgeois ◽

...

Keyword(s):

Board Of Directors ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Routine Practice ◽

Unrelated Donor ◽

Roc Curve Analysis ◽

Advisory Committees ◽

Purine Analogue ◽

Gvhd Prophylaxis ◽

The Impact

Introduction: Prophylactic T cell depletion with antithymocyte globulin (ATG) remains a standard of care for GVHD prophylaxis during allotransplant (ASCT). Although the optimal ATG dosing strategy is still unknown, recent studies have reported that recipient absolute lymphocyte counts (ALC) at the time of ATG administration may predict survivals in ASCT with unrelated donors, suggesting that the dose (especially at the cut off of <0.1x109/L) and timing of ATG administration must be taken into account (Soiffer et al, JCO 2017; Kennedy et al, BBMT 2018). Our experience on the impact of lymphopenia at the time of ATG administration during allotransplant is reported here. Materials & Methods: All adults transplanted in our department between 01/2009 and 03/2019 with a Purine analogue/Busulfan/ATG based conditioning regimen and PBSC as source of graft from a matched or 9/10 mismatched donor were eligible. Reduced-intensity conditioning (RIC) regimen consisted of fludarabine 30mg/m²/day (d) from d-6 to d-2, busulfan 3,4 mg/kg/d from d-4 to d-3 and ATG (Thymoglobuline, Sanofi, Lyon, France) 2,5 mg/Kg/d, d-2 and d-1 (FB2A2) or the same but with clofarabine 30mg/m²/d in replacement of fludarabine with 1 or 2 d of ATG (CloB2A2/CloB2A1). Reduced-toxicity myeloablative conditioning regimens (RT-MAC) consisted of the same as FB2A2 but with 3 or 4 d of busulfan instead of 2 (FB3A2/FB4A2). All grafts were administered freshly on the day of the collection while patients (pts) had already received ATG. GVHD prophylaxis was ciclosporine alone for pts with a sibling donor while pts grafted with a matched (MUD) or a 9/10 mismatch (mmUD) unrelated donor received ciclosporine+MMF. We exhaustively looked at pts for whom a blood differential was available at the time of ATG administration in order to study the impact on OS, DFS and GRFS (no grade 3-4 acute GVHD, no moderate/severe chronic GVHD and no relapse) of a profound lymphopenia vs not. Results: Of 395 eligible pts, 116 (median follow-up for alive pts: 49 months) were documented with a differential at time of ATG administration, confirming that this analysis is not a routine practice in our department and probably in many centers. RIC was administered in 80 (69%) of the pts including 39 FB2A2, 12 CLOB2A2 and 29 CLOB2A1. RT-MAC was administered in 36 (31%) pts, including 27 FB3A2 and 9 FB4A2. Seventy-six pts had a myeloid disease while 40 had a lymphoid disease. Donor types were siblings (n=33), MUD (n=70) or 9/10 mmUD (n=13). For the entire cohort, 4y OS, DFS and GRFS were 56.2% (47-66), 40.9% (32-51) and 34.5% (26-45), respectively. No difference in survivals was observed between lymphoid vs myeloid pts, pts transplanted with sibling vs other donors, pts receiving a RIC vs a MAC or a CloB2 vs a FB2 RIC regimen. Median ALC at time of start of conditioning was .915x109/L (range: .010-15.780). No difference in terms of survivals was observed when considering pts under this threshold vs others. ROC curve analysis failed to identify a cut-off allowing to predict better survivals according to ALC at the time of ATG administration (ALC/ATG). Median ALC/ATG was .070x109/L (range: 0-2.300). No difference in terms of survivals was observed when considering pts under this threshold vs others. The same was true when considering .100x109/L as ALC/ATG cut-off. Regarding MAC, the median ALC/ATG was .100x109/L with no difference in survivals between pts under or above this value. The same was true for RIC with ALC/ATG cut-offs < median (.055x109/L) or <.100 x109/L. Interestingly, considering pts with ALC/ATG <.100 x109/L within the RIC setting, survivals were similar between those who received 1d (n=25) vs 2d (n=28) of ATG. This analysis was not performed for pts with ALC/ATG >.100 x109/L as only 4 of them received 1d of ATG vs 23 2d. The dose of CD34+ and CD3+ T cells infused had no impact also on survivals. Conclusion: This study demonstrates that profound lymphopenia at the time of ATG administration as part of a RIC as well as a RT-MAC Purine analogue/Busulfan/ATG based conditioning regimen has no impact on outcomes. Moreover, a reduced dose of ATG in RIC pts with profound lymphopenia at the time of ATG administration did not translate into better survivals. Other unknown factors rather than recipient lymphopenia remain to be discovered to optimize individualized dosing of ATG. Disclosures Peterlin: AbbVie Inc: Consultancy; Astellas: Consultancy; Jazz Pharma: Consultancy; Daiichi-Sankyo: Consultancy. Moreau:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Le Gouill:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche-Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support. Chevallier:Daiichi Sankyo: Honoraria; Incyte: Consultancy, Honoraria; Jazz Pharmaceuticals: Honoraria.

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