ALBERT

Description: Introduction: Allogeneic stem cell transplantation is a potentially curative treatment for patients with high-risk non-Hodgkin lymphoma (NHL). Fludarabine/busulfan based conditioning regimens are widely used in Europe for this purpose. Busulfan dose intensity discriminates between reduced intensity (FB2, 2 days of busulfan at 4 mg/Kg/d per os or 3.2 mg/kg/d iv) and reduced-toxicity myeloablative (FB3/FB4, 3 or 4 days of busulfan at 4 mg/Kg/d per os or 3.2 mg/kg/d iv) conditioning regimens (Bacigalupo, 2009). While some data have been recently published showing some advantages of higher busulfan dose intensity for myeloid malignancies, there is no such data available in the lymphoid setting. Methods: This was a large retrospective study conducted on behalf of the SFGM-TC including all adults allografted in France between January 2004 and December 2014 for NHL (n=378). Clinical data were obtained through ProMISe (Project Manager Internet Server), an internet-based system shared by all French transplantation centers. We aim to compare various outcomes (overall (OS) and lymphoma free (LFS) survivals, relapse incidence (RI), non-relapse mortality (NRM), acute and chronic GVHD) between those who received FB2 (n=277) or FB3/FB4 (n=101) as conditioning regimens. GVHD free relapse free survival (GRFS) was also studied (defined as alive with no previous grade III-IV aGvHD, no moderate or severe chronic GvHD (cGvHD) and no relapse). Results: Both groups were comparable for the following variables: median follow-up (FB2: 24.9 vs FB3/4: 23 months), gender (male 61% vs 53%), disease type (low-grade lymphoma 25% vs 21%, mantle-cell lymphoma 17% vs 13%, high-grade lymphoma 25% vs 21%, T cell lymphoma 32% vs 45%), disease status at transplant (complete remission/very good partial response 64% vs 62%, partial response 28% vs 31%, active disease 8% vs 7%), donor type (sibling 43% vs 49.5%, matched unrelated 56% vs 47), median number of previous courses of treatment (2 vs 2, p=0.44), stem cell source (peripheral blood 96% vs 95%). FB2 patients were significantly older (median 57.3 vs 53.1 years, p=0.07), have been transplanted more recently (median year of transplant: 2011 vs 2010, p=0.001) and have been more previously autografted (69% vs 50.5%, p=0.001). FB3/4 patients have been allotransplanted earlier during the evolution of their disease (median time between diagnosis and allograft 18.2 vs 33.8 months, p=30 months), there were also no significant differences between both groups in terms of OS, LFS, RI or NRM. In multivariate analysis there was a trend for worse outcome using FB3/FB4 regimens (OS: HR 1.46, 95%CI: 0.96-2.23, p=0.07; LFS: HR: 1.43, 95%CI: 0.99-2.06, p=0.05; RI: HR 1.54; 95%CI: 0.95-2.48, p=0.07). These results were also confirmed using a propensity score-matching strategy including 184 FB2 and 98 FB3/4 patients. Conclusion: This large retrospective study showed that reduced toxicity myeloablative fludarabine/busulfan regimens did not improve outcomes of adults allografted for NHL. FB2 conditioning regimen still should be considered as the standard of care conditioning regimen in this setting. To validate these results, prospective studies are needed, like the French prospective trial currently ongoing for myeloid diseases (NCT01985061). Also, new conditioning regimens and post-allograft strategies should be tested to improve outcomes of patients. Disclosures Peffault De Latour: NOVARTIS: Consultancy, Honoraria, Research Funding; PFIZER: Consultancy, Honoraria, Research Funding; ALEXION: Consultancy, Honoraria, Research Funding.

Description: Background Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for MDS patients (pts). Due to transplant-related mortality, only pts with short life expectancy are referred to HSCT, usually those with IPSS int-2 or high risk. The aim of this prospective study was to compare outcome in candidates for HSCT according to donor availability: no donor, HLA-matched sibling donor, 10/10 HLA-matched unrelated donor and 9/10 HLA-mismatched unrelated donor. Method SFGM-TC and GFM centers that had agreed on general recommendations concerning the management of MDS pts participated to the study (16 centers). Transplant indications were int-2 or high IPSS, int-1 with refractory thrombocytopenia or proliferative CMML. Pts were registered in this study if older than 50 years, when they acquired an indication for HSCT and in the absence of comorbidity contraindicating HSCT. A donor research was initiated at registration including HLA-matched sibling donor, HLA-matched unrelated donor (10/10) or mismatched donor for one allele. Other alternative donors (mismatched unrelated cord blood or 〉 1 mismatched donor) were not accepted. Transplantation was scheduled upfront if bone marrow blasts 〈 10% at inclusion or after treatment with AML like anthracycline-aracytine chemotherapy (CT) or azacitidine (AZA) if marrow blasts 〉 10% ideally within 6 months if a donor was identified. Recommended reduced intensity conditioning regimen consisted in fludarabine, busulfan and anti-thymoglobulin with peripheral stem cells (PB) as source of stem cells. Characteristics of pts and disease were compared within 3 groups: no donor, HLA-matched donor (sibling or 10/10), HLA-one mismatched donor (9/10). Overall and disease free survivals (OS, DFS) were compared using Kaplan Meier estimates. Cumulative incidences of complete remission and disease-related mortality were compared using Gray-test. Results From April 2007 to January 2013, 163 pts were included: 34 (21%) pts had no donor; 115 (71%) pts had an HLA-matched donor (34% sibling and 37% unrelated) and 14 (9%) pts had an HLA mismatched donor. Groups were well-balanced for age, gender, time from diagnosis to inclusion, WHO classification, bone marrow blasts at time of inclusion, cytogenetic (IPSS) and IPSS classification. WHO classification at time of inclusion was: AML post MDS in 12, RAEB1 in 29, RAEB2 in 82, CMML1 or 2 in 20, RCMD in 14 and other MDS in 6 pts. Cytogenetics were favorable in 49 (30%), intermediate in 37 (23%) and poor in 74 (45%) pts. IPSS was int-1 for 8%, int-2 for 69% and high for 23% of pts. Median follow-up was 38 months. 117 pts were treated by AZA and 40 by CT. Bone marrow blasts 〈 10% were achieved in 68% and 57% for pts without and with donor, respectively. 69% of pts with HLA-identical donor and 57% of those with HLA-mismatched donor were transplanted. Some pts with donors were not transplantation because of excess of marrow blasts in most pts (〉 10% in 3, 〉 20% in 20 pts), comorbidities contraindicating the transplantation acquired after inclusion (9 pts), early deaths (7 pts) and other causes in 3 pts. Four other pts scheduled for transplantation have not been transplanted yet. Probability of complete remission 12 months after inclusion was: 39% (95% CI: 22-55), 49% (95%CI: 40-58) and 46% (95%CI: 17-71) for pts without a donor, with an HLA-compatible donor and with HLA-mismatched donor. Disease-related mortality at 48 months was not significantly different in the 3 groups: 50 % (95%CI: 29-68), 38% (95%CI: 27-49), 51% (95%CI: 17-77). DFS was also not different in 3 groups: 18% (95%CI: 7-44), 25% (95%CI: 16-37) and 9% (95%CI: 1-57). In contrast, OS at 48 months was better in pts with HLA-compatible donor than in pts without donor or those with HLA-mismatched donor: 35% (26-49), 17% (6-43) and 8% (1-55), respectively, p=0.011 (Figure 1). The poor survival observed in pts transplanted with an HLA-mismatched donor may be due to their small number and requires further analysis in a larger cohort. Outcome was not different in pts receiving PB from HLA-matched sibling or from HLA 10/10 matched unrelated donor. Conclusion In a prospective study, we observed that int-2 or high risk MDS pts with a HLA-matched donor have an improved life expectancy as compared to pts without donor. This study confirmed that they should be referred to the transplantation before acquisition of comorbidity contraindicating HSCT. Disclosures: No relevant conflicts of interest to declare.

Description: Background Outcome of patients with intermediate or high risk IPSS myelodysplastic syndrome (MDS) is poor in the absence of hematopoietic stem cell transplantation (HSCT). Choice of the best stem cell source is debated in this poor risk population. Unrelated cord blood transplantation (UCBT) has been used for patients lacking an HLA identical donor. This is the first study comparing well matched unrelated adult peripheral blood (PB) stem cell transplant to mismatched UCBT for patients with MDS. Method Patients with MDS transplanted from 2005 to 2011 with either unrelated CB or PB receiving a reduced intensity conditioning (RIC) were included. All PB donors were Human Leucocyte Antigens (HLA)-allele matched (10/10) or one allele mismatched (9/10) (-A, -B, -C, DRB1, -DQB1). Overall survival (OS) and disease-free survival (DFS) were estimated by Kaplan-Meier. Relapse incidence (RI), non-relapse mortality (NRM), engraftment, acute and chronic graft-versus-host disease (GVHD) were calculated using cumulative incidence (CInc) methods. Risk factors for outcomes were analyzed by Cox and Fine & Gray models. Results 502 patients transplanted with PB or 129 with CB (80 with double units) were compared. Among the PB recipients, 363 (72%) were 10/10 matched and 123 (25%) 9/10 matched. Most CB (98%) recipients had at least one HLA mismatch on 6 antigens tested (-A, -B antigen level and DRB1 allelic level), 32% had one mismatch and 66% had 2 mismatches. Median follow-up was 12 months for PB and 24 months for CB. MDS was transformed into AML in 416 patients. MDS WHO classification was: RA in 37, RCMD in 31, RAEB1 in 50 and RAEB2 in 87 and unclassified in 10 patients. Considering only patients with MDS, cytogenetic according to IPSS was: good in 96, intermediate in 57 and poor in 65 patients. PB and CB groups were different for age, gender, incidence of secondary AML (CB: 71% vs PB: 64%) and conditioning regimen. CInc of engraftment was lower in CB patients, 78 vs 96% (p

Description: Background Unrelated cord blood transplantation (UCBT) after reduced intensity conditioning regimen (RIC) has extended the use of cord blood in elderly patients and those with co-morbidities without an HLA identical donor, although relapse post transplant remains a concern in high risk AML patients. HLA incompatibilities between donor and recipient might enhance Natural Killer (NK) cell alloreactivity after allogeneic hematopoietic stem cell transplantation (HSCT). We previously observed that the quality of NK cell reconstitution was impaired after haploidentical HSCT, impacting on graft versus leukemia (GvL) effect, but was preserved after UCBT in a small cohort of patients. Methods To evaluate RIC-UCBT in patients with acute myeloid leukemia (AML), a prospective phase II multicentric trial was conducted in France, whose primary objective was to show a reduction in non-relapse mortality (NRM) from 40% (based on registry data) to 20%. Seventy-nine patients were enrolled for a de novo or secondary AML in complete remission (CR). The conditioning regimen consisted of cyclophosphamide (50mg/kg) + fludarabine (200mg/m2) + total body irradiation (2Gy), CsA +MMF as GVHD prophylaxis and GCSF from day +1. Patients were enrolled in 23 centers from October 2007 to September 2009. Engraftment rate was 87 % at day+60. At 2 years, overall survival, incidence of relapse and LFS were respectively 44%, 46% and 35%. Peripheral blood samples were collected following UCBT in order to realize an extensive phenotypic and functional study of NK cells. Studies were started at 1 month (M1) post UCBT with available samples for 62 out of the 69 included patients, and were compared to 20 healthy donors and 15 cord blood (CB). Results Total CD3+ T-cells were 117 /mm3 at M1 (range 0-934), and 465 /mm3 at M3 (range 0-2917). CD19+ B-cells were 36/mm3, (range 0-524) and 342/mm3 (range 0-2990) at M1 and M3 respectively. NK cell recovery was prompt, representing 47% of the total lymphocyte population at M1 (186 CD3-CD56+ NK cells/mm3), 30% at M3 (239/mm3; range 2-767) and decreasing to normal rate at M6 (20% of lymphocytes). At M1 post-UCBT, NK cells exhibited high rate of CD56bright, NKG2A, and KIR2DL4 associated with a decreased expression of CD8 and CD161, compared to CB and healthy donors. These immature characteristics were transient and return to normal value from M3 or M6 post-UCBT. Interestingly, we also observed a significant increased expression of the activation markers CD69, and HLA-DR during the whole period of the study, compared to CB and healthy donors, which probably reflects a persistent proliferation state of the NK cells. On the other hand, NK cells post-UCBT were indistinguishable from CB and healthy donors control samples for other receptor tested such as NKp30, NKp46, NKp80, and NKG2D. Notably, Expression of KIR2DL1 was decreased at M1 and M3 but reached similar values to controls at M6, whereas, KIR3DL1 was increased during the whole study. To determine the significance of these phenotypic features, we assessed polyfunctional ability of NK cells following UCBT by a combined analysis of the degranulation (CD107a), and the production of IFN-γ and TNF-α. This study reveals that NK at M1 post-graft exhibited a transient higher ability to produce IFN-γ than healthy donors (p

Description: The Complement system consists of several serum proteins and receptors that belong to the innate immune response. It is activated by three possible pathways leading to the production of pro-inflammatory factors and the formation of the membrane attack complex. As it is known to be implicated in the physiopathology of several immune-mediated diseases, we investigated its role in GVHD in both humans and a mouse model. Thirty nine patients allografted for diverse haematological malignancies in our institution following myeloablative conditioning (n=22) or reduced intensity conditioning (RIC) (n=17) entered prospectively the study. Extensive exploration of the Complement system was carried out before and sequentially after allogeneic haematopoietic stem cell transplantation (HSCT). An activation of the classical pathway, as defined by a decrease of C3 and C4 proteins below normal values and of at least 50% of their pre-HSCT levels, was observed in 10/39 patients. Such activation was found in 9/22 (40%) patients who received myeloablative conditioning and in 1/17 (5.8%) patients allografted with RIC. This phenomenon occurred during the 4 first weeks after HSCT in 7 patients, at two months in one case and after withdrawal of immunosuppression in 2 patients. We observed a strong association between Complement activation and the development of acute gastrointestinal (GI) GVHD. Nine of the 10 patients who activated the Complement system (90%) developed GI GVHD within two weeks following the activation. By contrast only 4 of the 29 who did not activate the system, all of whom had received a RIC, developed GI GVHD (13.8%) (p

Description: We aimed to determine whether outcome of HSCT from an unrelated donor has improved over time for patients with severe acquired aplastic anemia (SAA) and, if so, to determine whether improvement resulted from changes in patient selection, changes in transplantation technique, or both. We thus analyzed the outcome of 89 patients (median age 17 years, range 0–52) who received such transplantations between 1989 and 2004. We compared two cohorts of patients transplanted within two successive time-periods (1989–1998 and 1999–2004) associated with probabilities (± 95% confidence interval) of 5-year survival significantly different: 29% ± 7% and 50% ± 7%, respectively (P

Description: Background: Unrelated cord blood transplantation (UCBT) after reduced intensity conditioning regimen (RIC) has extended the use of UCB in elderly and unfit patients without an HLA identical donor. KIR ligand incompatibility between donor and recipient might favor Natural Killer (NK) cell alloreactivity after UCBT in AML patients (Wilhemze et al, 2009), although contradictory results were reported (Brunstein et al, 2009). We previously reported the results of the biological NK cell reconstitution after RIC-UCBT in a French prospective phase II multicentric trial (Rio et al, 2015). We showed that NK cells generated from RIC-UCBT exhibited features of transient immaturity and stable activation, correlating with a high ability to produce IFN-γ and a quick restoration of the ability both to produce TNF-α and degranulate (Souchet et al, ASH 2013). The aim of the present study is to analyze the impact of KIR ligand incompatibilities and NK cell reconstitution on OS, DFS and TRM after RIC-UCBT in a prospective trial. Materials and methods: Seventy-six patients with a de novo or secondary AML in complete remission were enrolled in 23 centers from Oct. 2007 to Sept. 2009. Peripheral blood samples were collected during the first year following UCBT in order to realize an extensive prospective phenotypic and functional study of NK cells. DNA samples were also collected in recipient and cords blood to perform KIROTYPE and HLA-C allelic typing. NK biological data were available at M1 for 54 patients. The inhibitory Killer-Immunoglobin Receptors (KIR) KIR2DL1, and KIR2DL2/3 bind KIR ligand C2 and C1 respectively, resulting in inhibition of NK-cell mediated lysis. Recipients and UCB were classified into C1 or C2 family depending on their HLA-C typing (C1-C1, C1-C2 or C2-C2). Results: Among the 54 patients, 35 events occurred (relapse or TRM). Median EFS and OS were 13.2 and 18.3 months, respectively. Recipients C2-C2 had a significant worse EFS and OS than C1-C1 or C1-C2 (median EFS C2-C2=3.8 month vs 15.1 month for C1-x; p=0.002); median OS C2-C2 3.8 months vs 29.9 months for C1-x; HR=6.12, IC95% [2.069; 18.113], p=0.001). High intracellular staining of CD107a, reflecting the capacity of NK degranulation with HLA negative K562 target, correlated with better OS. CD107a expression was divided in 2 groups at median (=51%). Median OS of CD107 (0-50%) was 12.8 months vs 20.9 months for CD107a (51-66); p=0.029. Relapse risk was highly increased in recipients C2-C2 (HR=5.04 (IC 95% [1.23; 20.56], p=0.02). Low expression of CD16 (HR=0.97, IC95% [0.937; 0.999], p=0.043), high expression of HLA-DR (HR=1.08, IC95% [1.031; 1.123], p=8e-04) on NK cells, and recipients C2-C2 (HR=9.44, IC95% [1.311; 67.882], p=0.026) significantly increased the risk of TRM. The inhibitory KIR2DL1 receptor binds to C2 ligands. Of interest, KIR2DL1 was significantly decreased on C2-C2 recipients NK cells at M1, as compared to C1-x recipients NK cells. On the contrary, KIR2DL2/3 and KIR3DL1 restored promptly, suggesting a sequential expression of KIRs. As interaction between inhibitory KIRs and their ligands are essential for NK cells to become functional ("licensing" process), we can hypothesize that the weaker expression of KIR2DL1 on C2-C2 NK cells alters the licensing process, rendering the NK cells hypo-responsiveness. Conclusion: Recipient C2-C2 is correlated with a worse outcome (EFS, OS, relapse, TRM) after RIC-UCBT in a prospective trial for AML patients. Weak capacity of degranulation and low expression of CD16 are associated with worse OS and increased TRM, respectively. These features can reflect an alteration of the NK licensing process and might have impact on clinical outcome after UCBT. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 1187 Poster Board I-209 Background and aim: Del (13q), t (4;14) and del (17p) are well-recognized poor prognostic genetic abnormalities in multiple myeloma after standard chemotherapy and autologous stem cell transplantation (SCT). We investigated the prognostic impact of these genetic abnormalities, detected by fluorescence in situ hybridization (FISH), on the outcome in patients who underwent allogeneic SCT. Patients and methods: This is a retrospective study performed in 20 centres for a total of 175 patients, using the database register of the SFGM-TC and the cytogenetic files of the IFM and MAG groups. The median age of the population at diagnosis was 51 years (range, 28-62 years). FISH analysis was performed either at diagnosis or at relapse before allograft. Chromosomal abnormalities were found in 127 of 175 patients (73%), distributed as follows (in percent of patients evaluable for each abnormality): 59% for del (13q), 26% for t (4;14), 25% for del (17p), 24% for t (11;14) and 4% for t (14;16). Béta2microglobuline was superior to 4 mg/L in 51% and more than 92% had received at least one prior high-dose therapy followed by autologous SCT. Forty percent of patients were transplanted in the first course of the disease. Most patients (79%) received two or less lines of treatments before transplantation. Prior treatments included thalidomide and bortezomib in, respectively, 25% and 27% of cases. At transplant, 12% of patients were in complete response (CR), 6% in very good partial response (VGPR), 66% in partial response (PR), 8% in stable disease (SD) and 8% in progressive disease (PD). The median time from diagnosis to transplant was 15 months (range, 4-175 months). Seventy seven percent of patients received reduced conditioning regimen, including antithymoglobulin (ATG) in 52% of cases. Peripheral blood and bone marrow were used as the source of cells in 78% and 19%, respectively. Most donors (69%) were match related donors. Results: Best response to transplant was CR, VGPR, PR, SD and PD in, respectively, 38%, 12%, 33%, 7% and 10% (among 130 patients with available data). With a median follow-up of 36 months, the 3-year progression free survival (PFS) and overall survival (OS) were 34% and 52%, respectively. Three-year post-transplant progression occurred in 53%. One-year transplant-related mortality (TRM) was 21%. Grade II to IV acute graft-versus-host disease (GvHD) was present in 33%. Limited and extensive chronic GvHD occurred respectively in 16% and 23% of evaluable patients. In univariate analysis, del (13q), t (4;14) and del (17p) had no impact on the PFS, OS and progression. Three-year PFS and OS were, respectively, 39% and 53% for del (13q), 29% and 38% for del (17p), 26% and 38% for t (4;14), 25% and 43% for t (11;14), 31% and 45% for the group of patients without any of these cytogenetic abnormalities. Patients transplanted in the first course of the disease with t (4;14) (n=14) and with del (17p) (n=6) had a 3-year PFS of 36% and 44%, respectively. In multivariate analysis, better PFS was significantly associated with younger age (P= 0.02, HR=1.1), sensitive disease status at transplant (P=0.04, HR=0.55) and two or less prior lines of treatments (P

Description: BACKGROUND: Few therapeutic options are currently available for patients (pts) with severe aplastic anemia (SAA) refractory to antithymocyte globulin (ATG) plus ciclosporine (CsA) and not eligible for allogeneic stem cell transplantation. It has recently been reported that eltrombopag (ELT), a TPO receptor agonist, is efficient to improve tri-lineage blood counts in this setting. However, real-life use of this drug is still largely unknown. In pts with SAA refractory to ATG, physicians can accede to ELT in France through a compassionate use program. We took advantage of this program to assess the efficacy and safety of ELT in SAA pts. PATIENTS AND METHODS: The French National Reference Center for Aplastic Anemia conducted this study in pts who received ELT for the treatment of SAA. Latest guidelines were used to define disease severity, treatment indication, and response rates (Marsh et al, BJH 2014). The diagnosis of SAA was confirmed by marrow biopsy and Camita criteria for all pts. Pts were eligible if they received at least 2 months of ELT alone or in combination with other treatment in case of relapsed/refractory disease or front-line therapy for pts not eligible to the association of ATG and CsA. Pts were identified through a national e-mailing on behalf of the French reference center for SAA and the French Society of Hematology. All data presented here were collected at the reference date of June 26th, 2016. The study was conducted according to Helsinki's Declaration. RESULTS: Forty-six pts (male, 54%) who received ELT between July 2012 and February 2016 were identified in 17 French centers. Indications for ELT were relapsed/refractory SAA in 35 pts (76%) after 1 (49%), 2 (29%) or 3 (9%) courses of CsA+ATG. Eleven pts considered unfit for ATG also received the drug as first line therapy. The characteristics of the pts according to ELT indications are shown in Table 1. Median age at time of ELT initiation was 61 years [IQR 40 to 70]. 44 pts had idiopathic SAA including 17 (37%) with a detectable PNH clone (median size 7%). Two pts (4%) with dyskeratosis congenita also received ELT. ELT was introduced 17 months [8-50] after the initial diagnosis of SAA and with a median of 6 months [3-14] after the last course of immunosuppressive therapy. The maximal dose was 150 mg/day [100-150] for a median duration time of 6 months [4-12]. At last follow-up 22(48%) pts were still on treatment, 4(9%) pts stopped because of good hematological response, 1(2%) and 15(33%) after limited toxicity and failure to improve hematological status. Before treatment, median neutrophils count was 790/mm3 [500-1215] and pts received a median number of 4 red blood cells packs [2-4] and 3 platelets apheresis units [2-4] every month. Neutrophils counts were 765 [515-1475], 1100 [600-1800], 1200 [670-1915] and 1200/mm3 [757-2300] at 1, 3, 6 months and at last follow-up respectively. The rates of transfusion independence for both red cells and platelets were 7%, 33%, 46% and 46% at 1, 3, 6 months and at last follow-up. In pts achieving transfusion independence, hemoglobin and platelets level improved of 3 gr/dL [1.4, 4.5] and 42 G/L [11, 100], respectively. The rate of transfusion independence was not different among first line and refractory pts (p=0,5). We did not observe any response in the 2 patients with dyskeratosis congenita. No factor associated with hematological response to ELT was identified. Liver toxicity (cytolysis) occurred in 11 pts (1 grade 3 that required withdrawal of the treatment and 10 grade 1 who responded to dose reduction). 2 pts had a grade 2 intestinal toxicity which improved after dose reduction. Other side effects where related to SAA (28% infections, 13% hemorrhages). Bone marrow karyotype analysis after ELT was done in twelve pts (26%) (median time 14 months [5-22] after ELT start). In 10 pts the karyotype was normal, in one, trisomy 8 was identified (already seen at SAA diagnosis), and karyotype was a failure in 1 pt. CONCLUSION: We report here the first real-life multicenter study about the use of ELT in SAA. In a particular severe pts population with no other treatment possibility, we confirm a 40% rate of hematological improvement with transfusion independence. Some of the pts who were not eligible to ATG plus CsA (comorbidities) also received ELT first line with similar response rates. Elderly pts unfit for ATG may thus benefit from this treatment which at the best should be given through prospective clinical trials. Table 1 Table 1. Disclosures Ades: Celgene, Takeda, Novartis, Astex: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Terriou:Novartis: Consultancy; amgen: Consultancy. Peffault de Latour:Alexion: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Research Funding.

Description: Background: Matching for all alleles of the HLA-A, -B, -C, and -DRB1 loci (8/8 match) is associated with the highest overall survival (OS) rates after unrelated donor (URD) hematopoietic stem cell transplantation (HSCT). In Europe, patients (pts) are also matched at the HLA-DQB1 loci (10/10 match) with no overall evidence of improved OS. HLA-DPB1 mismatching has been associated with a higher risk of acute graft-versus-host disease (aGvHD) and a decreased risk of relapse. A detrimental role of additional HLA-DQB1, HLA-DPB1 and HLA-DRB3/4/5 mismatches (MM) has been recently identified on OS but only in 7/8 HLA-A, -B, -C, and -DRB1 loci URDs HSCT. We investigated the impact of HLA-DPB1 and HLA-DRB3/4/5 MM on outcomes in a large cohort of 10/10 matched URD HSCTs. Patients and methods: 2,393 pts who received an initial HSCT from a 10/10 matched URD in 35 French centers were included between January 2000 and October 2012. Informed consent was obtained in accordance with the Declaration of Helsinki. High-resolution typing was performed for HLA-A, -B, -C, -DRB1, -DQB1, -DPB1 and -DRB3/4/5 loci for all donor/recipient pairs. Clinical data were obtained through ProMISe (Project Manager Internet Server), an internet-based system shared by all French transplantation centers. Impact of HLA-DRB3/4/5 and -DPB1 MM was quantitatively and qualitatively evaluated. For quantitative evaluation, patients were classified into 5 different groups according to their global matching level for the 7 considered loci (14/14, 13/14, 12/14, 11/14, 10/14). For qualitative evaluation, MM type and directionality (GvH and host versus graft (HvG) directions) were evaluated. HLA-DPB1 MM were classified as permissive or non-permissive (K Fleischhauer, Lancet Oncol. 2012). The primary composite endpoint for the analysis was GvHD-free and relapse-free survival (GRFS). We defined early GRFS as being alive at 3 months after HSCT with no previous grade III-IV aGvHD and no relapse and late GRFS as being alive 〉3 months with no previous grade III-IV aGvH, no relapse and no moderate or severe chronic GvHD (cGvHD). Late GRFS was evaluated at months 6, 12, 24 and 36 after HSCT. Acute GvHD, cGvHD, relapse and OS were also studied. Models were adjusted for HSCT period, disease risk, age, sex matching, stem cell source, and conditioning regimen. Results: Table 1showspopulation characteristics and distribution of cumulative MM. The median follow-up was 59 months. Compared to 14/14 pairs, quantitative evaluation showed a significantly lower early GRFS for pts who received a 10-11/14 (Hazard Ratio HR 2.0, 95% CI 1.4 to 2.9, p=0.0003) or a 12/14 URD HSCT (HR 1.4, 95% CI 1.1 to 1.8, p=0.01). This was related to a significantly increased risk of grade III-IV aGVHD associated with 10-11/14 (HR 2.3, 95% CI 1.5 to 3.7, p=0.0004) and 12/14 pairs (HR 1.7, 95% CI 1.2 to 2.4, p=0.003). 10-11/14 pairs were also associated with a higher risk of death at 3 months (HR 2, 95% CI 1.1 to 3.6, p=0.024). Qualitatively, in pts matched for HLA-DRB3/4/5 but MM for HLA-DPB1 (n=1846, 77.1%), 2 HLA-DPB1 MM and non-permissive HLA-DPB1 MM were associated with a lower early GRFS (HR 1.4, 95% CI 1.1 to 1.9, p=0.01 and HR 1.3, 95% CI 1.0 to 1.7, p=0.02 respectively) due to an increased risk of aGvHD (HR 1.7, 95% CI 1.2 to 2.5, p=0.002 and HR 1.50, 95% CI 1.08 to 2.08, p= 0.017 respectively). Outcomes were not influenced by either GvHD or HvG mismatch directions. Late GRFS analyses once adjusted were not significantly different according to MM numbers, type and directions. Only 19 pairs (0.8%) were DPB1 matched and DRB3/4/5 mismatched (high linkage disequilibrium between DRB3/4/5 and DRB1); HLA-DRB3/4/5 MM could thus not be qualitatively analyzed. Conclusion: MultipleHLA-DPB1 and HLA-DRB3/4/5 MM have an early impact after 10/10 matched URDs HSCT. The best outcomes are seen in 13 and 14/14 pairs. Early GRFS is significantly impacted by 10-11/14, 12/14, 2 DPB1 MM as well as non-permissive HLA-DPB1 MM URD HSCT which is related to an increased risk of grade III-IV aGvHD. There is a significantly increased risk of mortality for 10-11/14 pairs at 3 months. Prospective evaluation of matching for HLA-DPB1 and HLA-DRB3/4/5 is warranted to reduce early post-HSCT toxicity in donor-recipient 10/10 matched pairs. Disclosures Michallet: Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Astellas Pharma: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria. Peffault De Latour:Pfizer: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Research Funding.