Abstract: Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) have both demonstrated impressive clinical activity in relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL). In this study, we analyzed the outcome of 809 patients with R/R DLBCL after two or more previous lines of treatment who had a commercial chimeric antigen receptor (CAR) T cells order for axi-cel or tisa-cel and were registered in the retrospective French DESCAR-T registry study ( NCT04328298 ). After 1:1 propensity score matching ( n  = 418), the best overall response rate/complete response rate (ORR/CRR) was 80%/60% versus 66%/42% for patients treated with axi-cel compared to tisa-cel, respectively ( P   〈  0.001 for both ORR and CRR comparisons). After a median follow-up of 11.7 months, the 1-year progression-free survival was 46.6% for axi-cel and 33.2% for tisa-cel (hazard ratio (HR) = 0.61; 95% confidence interval (CI), 0.46–0.79; P  = 0.0003). Overall survival (OS) was also significantly improved after axi-cel infusion compared to after tisa-cel infusion (1-year OS 63.5% versus 48.8%; HR = 0.63; 95% CI, 0.45–0.88; P  = 0.0072). Similar findings were observed using the inverse probability of treatment weighting statistical approach. Grade 1–2 cytokine release syndrome was significantly more frequent with axi-cel than with tisa-cel, but no significant difference was observed for grade ≥3. Regarding immune effector cell-associated neurotoxicity syndrome (ICANS), both grade 1–2 and grade ≥3 ICANS were significantly more frequent with axi-cel than with tisa-cel. In conclusion, our matched comparison study supports a higher efficacy and also a higher toxicity of axi-cel compared to tisa-cel in the third or more treatment line for R/R DLBCL.

Abstract: Background . Anti-CD19 Chimeric Antigen Receptor (CAR) T-cells are a major therapeutic advance in the management of patients (pts) with relapsed/refractory aggressive B-cell lymphoma (R/R aggressive BCL) with reported overall response rates between 40% and 83% in the pivotal trials (ZUMA1, JULIET, TRANSCEND) as well as in the real-life cohorts with either axicabtagene ciloleucel (axi-cel, Yescarta) or tisagenlecleucel (tisa-cel, Kymriah). However, a significant number of pts will experience progression or relapse after infusion with an estimated 24-month progression-free survival (PFS) of between 33% and 42%. DESCAR-T is a nationwide registry that aims to collect real-life data for all pts treated with commercialized CAR T-cells in France. It represents a unique opportunity to investigate the outcome of pts who relapse after CAR T-cell therapy. Patients and Methods . In all, 680 pts with R/R aggressive BCL were registered in DESCAR-T from August 2018 and 550 were infused at the time of the present analysis (April 12, 2021) with either axi-cel (n=350) or tisa-cel, n=200). All pts gave informed informed consent before DESCAR-T registration. Progression and relapse after CAR T-cells were defined based on the Cheson 2014 response assessment criteria. Results . With a median follow-up (F-up) of 7.9 months, 238 pts (43.3%) out of 550 treated pts relapsed, after axi-cel in 136 pts (F-up = 9.0 months [5.1 - 9.7]) and after tisa-cel in 102 pts (F-up = 7.8 months [5.9 - 10.4] ). Histological subtypes were DLBCL (n 178, 74.8%), PMBL (n=11, 4.6%), HGBCL (n= 3, 1.3%), transformed follicular lymphoma (tr FL) (n=31, 13%), or other histologies (FL n=2, PCNSL n=1, tr MZL n=3, unclassifiable hodgkin/DLBCL n=9). At time of registration, median age was 62 years (range 18;77), 43.6% were aged & gt;65 yrs, and 67.2% were male; 184 (79.7%) presented with advanced disease (stage III or IV), and 13 (5.9%) with low age-adjusted International Prognostic Index (aaIPI), 82 (37.1%) with low-intermediate aaIPI, 110 (49.8%) with high-intermediate aaIPI, and 16 (7.2%) with high aaIPI. At time of CAR T-cell infusion, 36 (18.9%) pts presented with ECOG PS & gt;=2 and 72 (38.9%) with an elevated LDH level. The median number of lines prior to CAR T-cell infusion was 3 (range 2-9), including 48 (20.1%) transplant (46 auto-HSCT and 2 allo-HSCT). Median time between order and infusion was 50 days (IQR 43; 59). Bridging therapy was administered to 87.8% of the pts, with a high-dose regimen including combined immunochemotherapy for 84.5% of the pts. Failure after CAR T-cells occurred after a median time of 2.71 months (range 0.2; 21.5), 54 (22.7%) being during the first month after infusion ( & lt; M1) and 156 (65.5%) during the first-three months after infusion ( & lt;M3). At failure, 154 (64%) patients received treatments that maybe combined and described as followed : 70 (45.5%) lenalidomide, 70 (45.5%) various immunotherapies (rituximab, daratumomab, polatuzumab), 31 (20.1%) a combined immunochemotherapy with various regimens (R-DHAX, RICE, Pola-R-Benda,...), 21 (13.6%) an anti-PD1 immune checkpoint inhibitor (Nivolumab, pembrolizumab), 11 (7.1%) bi-specific T-cell engagers (TCE), 18 (11.7%) radiotherapy, and 3 a transplant (1 an auto-HSCT and 2 an allo-HSCT). The overall response rate to the salvage therapy after CAR T-cells was 11% (complete response rate 5.2%). The median PFS was 2.8 months (95% CL, 2.4 -3.1). The median overall survival (OS) was 5.2 months (95% CL, 4.1- 6.6) (Figure 1A). The median OS was even shorter in pts who failed during the first month (1.9 months [95% CL, 1.1- 3.2] vs 6.7 months [95 CL 5.5 : 9.3] p & lt;0.0001) (Figure 1B). 26.9% of the pts in the overall cohort were alive at 6 months, but only 18.9% were alive in the group of pts relapsing during the first month. In multivariate analysis, predictors of OS were high LDH level at time of infusion, time to failure & lt; 1 month after CAR T-cells, no access to immuno-oncology treatment such as TCE or lenalidomide. Conclusion . This study is the first analysis reporting the outcome of patients with R/R aggressive BCL relapsing after anti-CD19 CAR T-cells. These results demonstrate the poor outcome of these pts and identifies the need for further innovative treatment strategies. Figure1. Overall survival from the CAR T-cell infusion in patients with R/R LBCL relapsing after CAR T-cells. (A) overall population. (B) according to the interval between CAR T-infusion and relapse ( & lt; 1 month and & gt; 1 month) Figure 1 Figure 1. Disclosures Di Blasi: Novartis: Consultancy, Honoraria; Kite, a Gilead Company: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Bachy: Kite, a Gilead Company: Honoraria; Novartis: Honoraria; Daiishi: Research Funding; Roche: Consultancy; Takeda: Consultancy; Incyte: Consultancy. Cartron: Roche, Celgene-BMS: Consultancy; Danofi, Gilead, Novartis, Jansen, Roche, Celgene-BMS, Abbvie, Takeda: Honoraria. Le Bras: Takeda: Honoraria, Research Funding; Kite Gilead: Honoraria; Novartis: Honoraria; Celgene BMS: Research Funding. Feugier: Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Honoraria; Astrazeneca: Consultancy, Honoraria. Casasnovas: Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Kite: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Mohty: Amgen: Honoraria; Jazz: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; Pfizer: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Astellas: Honoraria; Adaptive Biotechnologies: Honoraria. Sesques: Kite, a Gilead Company: Honoraria; Novartis: Honoraria; Chugai: Honoraria. Morschhauser: Servier: Consultancy; Incyte: Membership on an entity's Board of Directors or advisory committees; Chugai: Honoraria; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genmab: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZenenca: Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract: Anti-CD19 chimeric antigen receptor (CAR) T-cells represent a major advance in the treatment of relapsed/refractory aggressive B-cell lymphomas. However, a significant number of patients experience failure. Among 550 patients registered in the French registry DESCAR-T, 238 (43.3%) experienced progression/relapse, with a median follow-up of 7.9 months. At registration, 57.0% of patients presented an age-adjusted International Prognostic Index of 2 to 3, 18.9% had Eastern Cooperative Oncology Group performance status ≥2, 57.1% received & gt;3 lines of treatment prior to receiving CAR T-cells, and 87.8% received bridging therapy. At infusion, 66% of patients presented progressive disease, and 38.9% had high lactate dehydrogenase (LDH). Failure after CAR T-cell treatment occurred after a median of 2.7 months (range: 0.2-21.5). Fifty-four patients (22.7%) presented very early failure (day [D] 0-D30); 102 (42.9%) had early failure (D31-D90), and 82 (34.5%) had late ( & gt;D90) failure. After failure, 154 patients (64%) received salvage treatment: 38.3% received lenalidomide, 7.1% bispecific antibodies, 21.4% targeted treatment, 11% radiotherapy, and 20% immunochemotherapy with various regimens. Median progression-free survival was 2.8 months, and median overall survival (OS) was 5.2 months. Median OS for patients failing during D0-D30 vs after D30 was 1.7 vs 3.0 months, respectively (P = .0001). Overall, 47.9% of patients were alive at 6 months, but only 18.9% were alive after very early failure. In multivariate analysis, predictors of OS were high LDH at infusion, time to CAR-T failure & lt;D30, and high C-reactive protein at infusion. This multicentric analysis confirms the poor outcome of patients relapsing after CAR T-cell treatment, highlighting the need for further strategies dedicated to this population.

Abstract: Background Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) have both demonstrated impressive clinical activity in relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). In the pivotal JULIET trial, tisa-cel led to a best overall response rate (ORR) of 52% with a 40% complete response rate (CRR) and a median overall survival (OS) of 12 months. In the ZUMA-1 trial, axi-cel was associated with an 83% ORR, a 58% CRR and a median OS of 26 months. In the absence of a randomized comparison and given the large differences in trial design precluding a robust matched-adjusted indirect comparison, controversy exists as to whether there are significant differences regarding both efficacy and safety between the two products. Methods We conducted a propensity score (PS)-matched comparison of axi-cel and tisa-cel in a large cohort of R/R DLBCL patients treated outside of clinical trials. All data were collected through the French DESCAR-T registry designed by the LYSA/LYSARC which aims to collect real-life data. The PS was calculated for each patient by using multiple logistic regression analysis against treatment category (axi-cel v tisa-cel) entering the following variables (assessed at time of lymphodepletion for most): age, ferritin, time from last treatment to CAR T-cell infusion, sex, histological diagnosis, LDH level, CRP, ECOG status, stage, number of previous treatment lines, use of a bridging therapy, response to bridging therapy if any, previous stem cell transplant, diameter of the largest tumor involved (with a cut-off set up at 5 cm), time from first commercial CAR T-cell order (of any type) of the center to CAR T-cell order for the patient (as a correlate for center experience for CAR T-cell practice), and treatment center. For all categorical variables, missing values (which were marginal for most parameters and balanced between CAR T-cell subtypes) were considered as a category to reduce the number of patients not included in the analysis. Of note, patients with primary mediastinal B-cell lymphoma were not included since approval has been granted for axi-cel only. The primary endpoint was OS. The following secondary endpoints were analyzed: best ORR and CRR (according to Lugano 2014 classification), progression-free survival (PFS) and duration of response (DoR). All time-to-event analyses used time of CAR T-cell infusion as the origin. PS-matching of the two patient cohorts was then conducted using PS rounded to one decimal place. Results An initial cohort of 504 patients with DLBCL (NOS, high grade or transformed from indolent lymphoma) and treated with axi-cel (n=321) or tisa-cel (n=183) was considered. Among others, patient characteristics were imbalanced regarding ECOG, and prior transplant rate with worse prognosis for patients receiving tisa-cel. After a 1:1 ratio PS-matching, outcome was compared between 144 patients treated with axi-cel and 144 patients treated with tisa-cel with no residual significant difference in baseline patient characteristics according to CAR T-cell type. After a median follow-up of 6.6 months (95% CI, 6.1-10.4 months), OS was not significantly different between axi-cel and tisa-cel (78% v 70% at 6 months respectively, P=0.44). Best ORR and CRR were significantly higher with axi-cel compared with tisa-cel (73% v 60%, P=0.02 and 56% v 36%, P & lt;0.001, respectively). There was no difference in DoR. PFS was significantly longer with axi-cel than tisa-cel (53% v 32% at 6 months respectively, P=0.011). Regarding toxicity, there was no significant difference in incidence of cytokine release syndrome (CRS) but axi-cel was associated with significantly more frequent and higher-grade immune effector cell-associated neurotoxicity syndrome (ICANS) (30.6% v 18.1% for grade 1-2 and 10.4% v 2.1% for grade ≥3 for axi-cel compared with tisa-cel, respectively, P & lt; 0.001). Conclusion In this study, after stringent PS-matching on a large patient population treated with CAR T-cell in real-life, there was no OS difference between axi-cel and tisa-cel. Axi-cel yielded higher ORR and CRR and significantly prolonged PFS compared with tisa-cel. However, greater efficacy came at the cost of higher neurotoxicity with axi-cel. These data could help in refining CAR T-cell subtype choice for different patient populations, with young and/or fit patients benefiting most from axi-cel while tisa-cel being most advantageous to elderly and/or unfit patients. Figure 1 Figure 1. Disclosures Bachy: Kite, a Gilead Company: Honoraria; Novartis: Honoraria; Daiishi: Research Funding; Roche: Consultancy; Takeda: Consultancy; Incyte: Consultancy. Di Blasi: Novartis: Consultancy, Honoraria; Kite, a Gilead Company: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Sesques: Chugai: Honoraria; Novartis: Honoraria; Kite, a Gilead Company: Honoraria. Cartron: Roche, Celgene-BMS: Consultancy; Danofi, Gilead, Novartis, Jansen, Roche, Celgene-BMS, Abbvie, Takeda: Honoraria. Roulin: Janssen: Other: Travel and meetings. Sylvain: Sanofi, Celegene, Roche, Abbvie, Sandoz, Janssen, Takeda: Consultancy. Bories: BMS: Honoraria; Novartis: Honoraria; Abbvie: Consultancy; Celgene: Consultancy; Gilead: Consultancy. Casasnovas: Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Kite: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Mohty: Astellas: Honoraria; Jazz: Honoraria, Research Funding; Pfizer: Honoraria; Sanofi: Honoraria, Research Funding; Novartis: Honoraria; Takeda: Honoraria; Janssen: Honoraria, Research Funding; Gilead: Honoraria; Celgene: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria; Amgen: Honoraria; Adaptive Biotechnologies: Honoraria. Thieblemont: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Bristol Myers Squibb/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses , Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Cellectis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses ; Hospira: Research Funding; Bayer: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses . Houot: Jsnssen: Honoraria; Novartis: Honoraria; Kite: Honoraria; Gilead: Honoraria; MSD: Honoraria; Bristol-Myers Squibb: Honoraria; CHU Rennes: Current Employment; Celgene: Honoraria; Roche: Honoraria. Morschhauser: Celgene: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Speakers Bureau; AstraZenenca: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genmab: Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy; Janssen: Honoraria; Chugai: Honoraria; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy; Incyte: Membership on an entity's Board of Directors or advisory committees.

Abstract: The value of pretransplant splenectomy in patients with myelofibrosis (MF) is subject to debate, since the procedure may preclude subsequent allogeneic hematopoietic cell transplantation (allo‐HCT). To determine the impact of pretransplant splenectomy on the incidence of allo‐HCT, we conducted a comprehensive retrospective study of all patients with MF for whom an unrelated donor search had been initiated via the French bone marrow transplantation registry (RFGM) between 1 January 2008 and 1 January 2017. Additional data were collected from the patients' medical files and a database held by the French‐Language Society for Bone Marrow Transplantation and Cell Therapy (SFGM‐TC). We used a multistate model with four states (“RFGM registration”; “splenectomy”; “death before allo‐HCT”, and “allo‐HCT”) to evaluate the association between splenectomy and the incidence of allo‐HCT. The study included 530 patients from 57 centers. With a median follow‐up time of 6 years, we observed 81 splenectomies, 99 deaths before allo‐HCT (90 without splenectomy and nine after), and 333 allo‐HCTs (268 without splenectomy and 65 after). In a bivariable analysis, the hazard ratio [95% confidence interval (CI)] for the association of splenectomy with allo‐HCT was 7.2 [5.1‐10.3] in the first 4 months and 1.18 [0.69‐2.03] thereafter. The hazard ratio [95% CI] for death associated with splenectomy was 1.58 [0.79‐3.14]. These reassuring results suggest that splenectomy does not preclude allo‐HCT in patients with MF.

Abstract: Reduced-intensity conditioning (RIC) regimens are increasingly used for allogeneic stem cell transplantation (allo-SCT). RIC has been shown to allow engraftment with minimal early transplantation-related mortality (TRM). However, in the context of RIC, predictive factors for acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) and their effect on outcome remain unknown. In this report, we analyzed the outcome of 101 high-risk patients (70 hematologic and 31 nonhematologic malignancies) who received an HLA-identical sibling allo-SCT after RIC, including fludarabine, busulfan, and antithymocyte globulin (ATG). The cumulative incidence of grade II-IV aGVHD was 36% (95% confidence interval [CI], 27%-45%), whereas the cumulative incidence of cGVHD at 2 years was 43% (95% CI, 33%-53%). In multivariate analysis, the incidence of aGVHD was significantly associated with the ATG dose infused during conditioning (P = .0005), whereas peripheral blood as stem cell source was the only predictive factor for the development of cGVHD (P = .0007). The 1-year cumulative incidences of disease progression or relapse in patients with (n = 69) and without (n = 31) GVHD (whatever its form or grade) were 30% (95% CI, 19%-41%) and 55% (95% CI, 37%-72%), respectively (P = .02), suggesting that a potent graft-versus-tumor (GVT) effect can be achieved in high-risk patients following RIC. Moreover, the GVT effect was closely associated with GVHD without an increased risk of TRM (cumulative incidence of TRM, 18% [95% CI, 10%-25%] ). Collectively, these results provide a framework for the refinement of RIC approaches designed to enhance the GVT effect with an acceptable risk of GVHD.

Abstract: Abstract 1952 Reduced intensity conditioning (RIC) regimens has been developed with the aim to perform safer allogeneic (Allo) stem cell transplantation (SCT) in population previously discarded because of higher SCT-related mortality. In this regard, the age of 55 years has been a long-lasting threshold above which standard Allo-SCT prepared with myeloablative conditioning (MAC) has been of limited use. Since a decade we now know that RIC can be safely used in this population. The RIC intensity remains however an issue: the more intensive, the more toxic but the less intensive, the less effective. In this study we prospectively assess, in patients (pts) over 55 years, eligible for an matched sibling Allo-SCT, the impact of a RIC with Fludarabin (30 mg/m2/day (D-5 to D-1)), IV Busulfan (0.8 mg/kg × 4/day (D-4 to D-3)) and rabbit anti-Thymocyte globulin (ATG) (2.5 mg/kg/day (D-2 to D-1). This phase II study followed a one-step Fleming procedure aiming to detect a decrease in non-relapse mortality (NRM) of 20% (α=0.01; β=0.10) as compared to literature data using standard MAC. To achieve this goal, a minimum of 74 analyzable pts were necessary and the inclusion of 82 pts were scheduled to anticipate drop-off after inclusion. Eventually, from 03/07 to 06/10, 82 pts have been included in 9 centers, of which 79 have been transplanted. Median follow-up is 24 months (10–50). All grafts were PBSC from a HLA identical sibling. CSA (2 mg/kg) was started on day −2. Median age is 60 (55–70) and male/female ratio 47/32. Karnofsky score was 90 (60–90). Diagnoses: AML=32; MDS=13; ALL=6; NHL=10; MM=13; CLL=4; Waldenström=1); 54 pts were in CR (CR1=31; CR2=15; CR 〉 2=8), 22 in PR or SD and 3 in PD after a median of 2 (1–7) lines of chemotherapy. All pts engrafted and 46 presented with aGVHD (Grade: 1 n=32; Grade 2: n=7; grade 3–4: n=6) for a 17% (10–23) cumulative incidence of G≥ 2 aGVHD. A total of 47 pts experienced cGVHD (Limited: N=28; extensive: N=19) at a median of 4.5 months (3–21) after transplant for a one year overall and extensive cumulative incidence of 57% (46–68) and 34% (25–45) respectively. 12 patients died from NRM. The 6 month and overall cumulative incidences of NRM were 5% (0–10) and 16% (9–23) respectively. Karnofsky score was not predictive of NRM. 25 patients relapsed at a median of 4.2 months (0.8–12) for a cumulative incidence of 32% (23–42). Relapse incidence differed according to disease pre-transplant status (9 of 46 CR1/CR2 vs. 16 of 33 beyond CR2 pts; p=0.008). Three year overall and disease-free survival probabilities were 59% (45–71) and 79% (67–87) respectively. Considering the CR1 AML population (N=21), median age was 61 years (56–70) and probabilities of NRM, relapse, OS and LFS were 14% (IC95=0–27), 14% (IC95=2-26XX), 72% (IC95=47–86) and 67%(IC95=43-83) respectively. Economical data covering transplant and first 18 month post-transplant periods have been prospectively collected and are under analysis. HRQL (Health Related Quality of Life) was assessed over a 1-year period with the EORTC QLQ-C30 questionnaire (Days −7, +80,+180,+360). The lowest functioning scores and highest symptom scores were experienced 80 days after transplantation. Thereafter the level of functioning and level of symptoms returned to baseline levels, which is reassuring in this population. This study presents prospective data in pts of 55 years and older and treated in a multicenter trial with RIC but not non-myeloablative CDT. Taking account patient characteristics, they first confirm that Allo-SCT is a valid option in this population. Second they prospectively put in light that in elderly people the use of RIC is associated with similar NRM than after non-myeloablative conditioning regimen. The use of two days of rabbit ATG is associated with a low GVHD-induced NRM without a high relapse risk. This is likely due to the good efficacy/toxicity balance achieved by combining IV Busulfan and ATG. Further refining of this association, by cautious tuning of the IV Busulfan dose, is under process in our program. Comprehensive phase II studies of this type, including economical and QOL data, have become a prerequisite prior to further more ambitious trials of novel modalities and strategies. Disclosures: Blaise: Laboratoire Pierre Fabre: Research Funding; Celgene: Research Funding.