Reduced-toxicity Conditioning Regimen Research Articles

Single HLA Mismatch Unrelated Donor Allogeneic Stem Cell Transplantation in Caucasian Recipients: Outcomes in HLA-A, -B, -C, -DRB1 and -DQB1 Mismatch Hematopoietic Stem Cell Transplantation: A Study on Behalf of the Francophone Society of Stem Cell Transplantation and Cellular Therapy (SFGM-TC) and the Francophone Society for Histocompatibility and Immunogenetics (SFHI)

▪INTRODUCTION: Matching 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), although there is no evidence of better OS. Data on Caucasian pts receiving a single HLA mismatch URD HSCT are still controversial. We therefore conducted a multicenter retrospective study to assess the impact of a single HLA mismatch (9/10 match) on outcomes after URD HSCT in a large cohort of French pts. METHODSWe collected data from 1092 pts who underwent HSCT between January 2000 and December 2012 at 32 French transplantation centers. Informed consent was obtained in accordance with the Declaration of Helsinki. High-resolution typing was performed for HLA-A, -B, -C, -DRB1, -DQB1 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. Endpoints of interest were classical HSCT outcomes: engraftment, Graft versus host disease (GvHD), treatment related mortality (TRM) and relapse. GvHD free relapse free survival was also studied (defined as alive with no previous grade III-IV aGvHD, no moderate or severe chronic GvHD (cGvHD) and no relapse). Myeloablative conditioning was defined as a combination of agents expected to produce profound pancytopenia and myeloablation within 1-3 weeks after administration; pancytopenia is long lasting, usually irreversible and in most instances fatal, unless hematopoiesis is restored by hematopoietic stem cell infusion (Bacigalupo, et al.. Biology of Blood and Marrow Transplantation, 2009). Models were adjusted for disease risk, recipient age, CMV and sex matching, stem cell source, GVHD prophylaxis and conditioning regimen. For adjusted analysis DQB1 was used as the reference category. Disease risk was classified as standard or high risk using the American Society for Blood and Marrow Transplantation Request for Information 2006 risk scoring schema. RESULTSPopulation characteristics are shown in Table 1. Gender balance was the only difference between groups (p<0.013). Median follow-up was 84 months. Engraftment rates were not different between groups (overall, 91.8% (95% Confidence interval (CI) (90.1 to 93.4)). Overall Cumulative Incidence of aGVHD grade II-IV and grade III-IV were 39.9% (95% CI, (38.0 to 41.8)) and 22.2% (95% CI, (20.2 to 24.2)), respectively. Myeloablative Conditioning (MAC) using Total Body Irradiation (TBI)>4Gy [Hazard Ratio (HR) HR:1.95 (95% CI, 1.45 to 2.63)] and high disease risk [HR :1.34 (95% CI, 1.09 to 1.66)] were significantly associated with an increased cumulative incidence of grade II-IV aGVHD, whereas only MAC with TBI>4Gy was a risk factor for grade III-IV aGVHD [HR:1.91 (95% CI, 1.28 to 2.87)].Overall Cumulative Incidence of cGVHD was 38.1% (95% CI, 35.9 to 40.1) at 84 months. Overall relapse rate was 33.8% (95% CI, 30.5 to 37.1) with no differences according to HLA mismatch subtype. CI of TRM was 36.0% (95% IC, 32.9 to 39.1). Single HLA-A mismatch [HR:1.55 (95% CI , 1.11 to 2.17)], high disease risk [HR:1.40 (1.12 to 1.74)], a female donor for a male recipient [HR:1.41 (1.10 to 1.79)], and the use of a MAC regimen [HR:1.50 (1.08 to 2.08)] were significantly associated with a higher TRM after adjusted analysis. Overall GRFS was 14.5% (12.1 to 17.3). Single HLA-A mismatch [HR:1.25 (95% IC, 1.01 to 1.54)] and high disease risk [HR:1.45 (95% IC, 1.26 to 1.67)] were significantly associated with a lower GRFS (Figure1). CONCLUSIONIn this large cohort of Caucasian pts who received a single HLA mismatch URD HSCT, high disease risk was the major prognostic factor related to higher rates of both acute GvHD and treatment related mortality, and eventually a lower GRFS. HSCT outcomes were similar according to HLA single mismatches except for HLA-A mismatch, which was associated with a significant increase in TRM, and a worse GFRS. This study also highlights the high rates of both TRM and relapse after single mismatch URD HSCT (9/10) which justifies the use of reduced toxicity conditioning regimens, as well as the addition of targeted therapies pre- and post- HSCT in this setting. [Display omitted] [Display omitted] DisclosuresMichallet: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:Amgen: Research Funding; Alexion: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.

Busulfan (Bu) in Combination with Double Nucleoside Analogues Fludarabine (Flu) and Clofarabine (Clo) Plus Vorinostat As a Novel Reduced Toxicity Conditioning Regimen for Allogeneic Hematopoietic Cell Transplantation (HCT) in Patients (pts) with Acute Leukemia

The combination of IV Bu and Flu is an effective and well-tolerated HCT conditioning regimen for patients with advanced acute leukemia. However, relapse remains the main reason for treatment failure. We combined two nucleoside analogues Flu and Clo, and showed cytotoxic synergy when combined with Bu, first in pre-clinical models, and subsequently in a randomized clinical study (Andersson BBMT 2011). We selected the optimized regimen from Andersson et al, and combined with escalating doses of the histone deacetylase inhibitor vorinostat in attempts to augment disease control without increasing toxicity. Herein, we describe our initial experience with this novel regimen for patients with advanced acute leukemia or MDS undergoing allogeneic HCT.Methods: Vorinostat (200mg to 1200mg) was escalated in cohorts of 3 patients, and administered 1 hour prior to the fixed regimen of Flu 10 mg/m2 followed by Clo 40 mg/m2 followed by Bu. The nucleoside analogs were infused over 1 hour once daily for 4 days, followed on each day by Bu, infused over 3 hours to a pharmacokinetically targeted daily area under the curve (AUC) of 5500 μMol-min ± 5%. Dilantin was given for seizure prophylaxis. GVHD prophylaxis was based on tacrolimus andmini-MTX, with the addition of rabbit anti-thymocyte globulin (4 mg/kg total dose) for unrelated donor transplants. The presence of minimal residual disease (MRD) was determined by multiparameter flow cytometry.Results: 21 patients (7 AML, 14 ALL) with median age 43 years (range 19-60) received an allogeneic matched sibling (n=10) or unrelated donor (n=11) HCT in CR1 (n=13), CR2 (n=1), primary induction failure (n=5), or relapse (n=2). Twelve patients had MRD or overt disease present at time of HCT. Ten patients had high-risk karyotype defined by t(9;22) (n=3), t(4;11) (n=2), complex (n=2), or del 5 or 7 (n=3). Median time from diagnosis to HCT was 5 months (range 3-48). Median time to ANC > 0.5 x 109/L and platelets > 20 x 109/L were 11 (range 10-15) and 12 days (5-30), respectively. Excluding grade 1 toxicities, the most commonly reported toxicities were nausea with maximum grade 2 (71%), followed by grade 2 or 3 mucositis (64%). Grade 2 or 3 reversible elevation of liver function tests was noted in 54% of pts, including 1 case of reversible VOD. No renal toxicities were noted. Two patients with prior systemic treatment for acute GVHD died of infections (disseminated adenovirus and E.coli sepsis). Ten patients achieved CR and clearance of MRD by day +30 after HCT; one patient had progressive disease and on patient died before disease restaging. Eighteen patients achieved 100% donor chimerism at 30 days following HCT, 2 patients remain with mixed chimerism by 100 day assessment following HCT, and 1 patient died before assessment. The incidence of grades II-IV acute GVHD is 43% and chronic extensive GVHD among 18 evaluable patients is 24%. With a median follow-up of 10 months among surviving patients (1-22), overall and progression-free survival at 6 months is 95% and 71%, respectively. Early results suggest excellent disease control in MRD negative patients (Figure).Conclusion: The Vorinostat-Flu-Clo-Bu combination is well-tolerated and did not add appreciable toxicity in these patients with high-risk leukemia. Longer follow-up is needed to better assess disease control. [Display omitted] DisclosuresCiurea:Spectrum Pharmaceuticals: Other: Advisory Board; Cyto-Sen Therapeutics: Equity Ownership. Patel:Ziopharm Oncology: Equity Ownership, Patents & Royalties; Intrexon: Equity Ownership, Patents & Royalties.

Improved Outcome of a Reduced Toxicity-Fludarabine, Cyclophosphamide, plus Antithymocyte Globulin Conditioning Regimen for Unrelated Donor Transplantation in Severe Aplastic Anemia: Comparison of 2 Multicenter Prospective Studies

Hematopoietic stem cell transplantation (HSCT) is a curative therapy for severe aplastic anemia (SAA); however, the optimal conditioning regimen for HSCT with an unrelated donor has not yet been defined. A previous study using a fludarabine (FLU), cyclophosphamide (Cy), and antithymocyte globulin (ATG) conditioning regimen (study A: 50 mg/kg Cy once daily i.v. on days −9, −8, −7, and −6; 30 mg/m2 FLU once daily i.v. on days −5, −4, −3, and −2; and 2.5 mg/kg of ATG once daily i.v. on days −3, −2, and −1) demonstrated successful engraftment (100%) but had a high treatment-related mortality rate (32.1%). Therefore, given that Cy is more toxic than FLU, we performed a new phase II prospective study with a reduced-toxicity regimen (study B: 60 mg/kg Cy once daily i.v. on days −8 and −7; 40 mg/m2 FLU once daily i.v. on days −6, −5, −4, −3, and −2; and 2.5 mg/kg ATG once daily i.v. on 3 days). Fifty-seven patients were enrolled in studies A (n = 28) and B (n = 29), and donor type hematologic recovery was achieved in all patients in both studies. The overall survival (OS) and event-free survival (EFS) rates of patients in study B was markedly improved compared with those in study A (OS: 96.7% versus 67.9%, respectively, P = .004; EFS: 93.3% versus 64.3%, respectively, P = .008). These data show that a reduced-toxicity conditioning regimen with FLU, Cy, and ATG may be an optimal regimen for SAA patients receiving unrelated donor HSCT.

Single Center Experience of Allogenic Hematopoietic Stem Cell Transplantation in 100 Patients with Myelodysplasia: The Impact of Graft-Versus-Host Disease

IntroductionAllogenic hematopoietic stem cell transplantation (Allo-HSCT) is a curative treatment for patients with myelodysplasia (MDS). However, because of age, MDS patients represent a challenging population for such an intensive treatment. Additionally, the low rate of HLA-identical donor has represented a major limitation in this strategy. Recently, reduced-intensity conditioning (RIC) regimens have made feasible Allo-HSCT in the elderly, although relapse rate might be increased. Additionally, the development of HSCT using alternative donors overcomes HLA-compatibility limitations. Graft-versus-host disease (GVHD) is a major post-transplant event, graft-versus-leukemia effect being counterbalanced by toxicity and impaired quality of life. The aim of this retrospective study was to report outcome of patients with MDS who underwent Allo-HSCT and to study the impact of GVHD.MethodsBetween 2003 and 2014, 100 consecutive patients presenting with MDS, or MDS-secondary AML, underwent Allo-HSCT in our institution. At diagnosis, 58 patients had ≥ 2 cytopenias. IPPS was low/intermediate-1 in 46% and intermediate-2/high in 54%, R-IPSS was very low/low in 25%, intermediate in 20% and high/very high in 55%. Cytogenetics, according to Disease Risk Index (DRI), was intermediate in 79% and adverse in 21%. Secondary MDS represented 27% of our cohort. Before Allo-HSCT, 42% received 5-Azacytidine, 27% intensive chemotherapy and 9% were transplanted upfront. At the time of Allo-HSCT, the median recipient age was 61 (19-71) years. Median time between diagnosis and Allo-HSCT was 12 months (1-131). After excluding patients transplanted upfront, 31 patients still had ≥5% blasts after treatment. Donors were HLA-matched in 70% (41% related, 29% unrelated), 30% were not HLA-matched (10% unrelated, 7% cord blood, 13% T-repleted haplo-HSCT). Stem cell source was peripheral blood stem cells in 90%. Twelve percent of patients received non-myeloablative (NMA) conditioning regimen, 75% RIC and 13% reduced-toxicity conditioning (RTC) regimens. Post-graft immunosuppression consisted in cyclosporine A (CSA) in 58%, CSA-Mycophenolate Mofetil (MMF) in 15%, CSA-Methotrexate in 14% and CSA-MMF-Cyclophosphamide for haplo-HSCT (13%).ResultsMedian follow-up was 37 months (3-197). The incidence of 3-4 acute GVHD at day 100 was 7% (95% CI = 2-12). The incidence of severe chronic GVHD at 3 years was 19% (95% CI = 11-27). One and 3-year non-relapse mortality (NRM) were 23 and 29% respectively. The cumulative incidence of relapse (CIR) at 1 year and 3 years 24% and 33% respectively. One and 3-year progression-free survival (PFS) were 52% (95% CI = 43-63) and 37% (95% CI = 28-49). One and 3-year overall survival (OS) were 60% (95% CI = 51-71) and 48% (95% CI = 39-60). At one year, 51 patients were alive and disease-free, including 61% (n=31) without immunosuppression. At the end of follow-up, 39 patients were alive and disease-free, including 85% (n=33) without immunosuppression and 77% (n=30) GVHD-free. Time-dependent analysis of GVHD impact (Table 1), adjusted on age, donor-type, DRI and conditioning regimen, revealed that acute GVHD strongly impacts on OS (HR 3.8, 95% IC = 2-7, p<0.01), PFS (HR 3.1, 95% CI = 1.7-5.6, p<0.01) and NRM (HR 12, 95% CI = 5.2-28, p<0.01). Chronic GVHD was statistically significant on CIR (HR 0.16, 95% CI = 0.04-0.7, p=0.02) and NRM (HR 2.8, 95% CI = 1-8, p=0.05). Pre-transplant disease characteristics did not have any impact by univariate analysis. Multivariate analysis did not find any impact of age, donor type, DRI and conditioning regimen in terms of OS, PFS, NRM and CIR.ConclusionOur results suggest that GVHD highly influences outcome, regardless of MDS and Allo-HSCT characteristics. It should be quoted that a significant number of patients are alive, long-term survivors, disease-free and GVHD-free suggesting good quality of life. These results invite defining better strategies of GVHD prevention while retaining disease control magnifying the existing graft-versus-leukemia effect.Table 1Time-dependent analysis of the impact of acute and chronic GVHD, adjusted on age (< or > 60), donor-type (HLA-matched or not matched), DRI and conditioning regimen (NMA, RIC or RTC).HR95% CIpAcute GVHDOS PFS NRM CIR3.8 3.1 12 0.42-7 1.7-5.6 5.2-28 0.09-1.7<0.01<0.01<0.010.2Chronic GVHDOS PFS NRM CIR0.7 0.8 2.8 0.20.3-1.5 0.4-1.8 1.01-8 0.04-0.80.4 0.6 0.050.02 DisclosuresVey:Celgene: Honoraria; Roche: Honoraria; Janssen: Honoraria.

The Best of Both? Megadose Stem Cells with CD34 Selection and T-Cell Addback Enables Engraftment from Mismatched Unrelated Donors Using Reduced Toxicity Conditioning in Primary Immunodeficiency

▪Background: The optimal approach for transplanting patients with primary immunodeficiency from a mismatched unrelated donor (MMUD) remains unclear. With reduced intensity conditioning, when bone marrow (BM) was used as the stem cell source in such patients we have previously observed a high rate of very low level donor chimerism (4 of 12 patients) requiring a second transplant procedure. The use of peripheral blood stem cells (PBSC) can overcome this but results in a high incidence of acute (≥ Gde II 10/21, Gde III-IV 5/21) and chronic (10/21, extensive 7/21) graft-versus-host disease (GVHD) (Rao et al in press). We hypothesized that the use of megadose CD34 selected stem cells from PB with addback of a T-cell dose akin to BM might facilitate engraftment through improved competition for the stem cell niche without severe GVHD.Methods: We prospectively analysed outcomes on 20 consecutive patients with primary immunodeficiency (SCID n=5, HLH n=3, Other PID n=12) transplanted from 8/10 (n=4) or 9/10 (n=16) HLA MMUD at our institution between 2011-2015. The mean age at transplant was 5.1 years. All patients received reduced toxicity conditioning regimens (12/20 Fludarabine/Melphalan/Alemtuzumab; 8/20 Fludarabine/Treosulphan/Alemtuzumab) with Cyclosporin (CsA) and mycophenolate mofetil (MMF) GvHD prophylaxis. CD34 selection of donor PBSC was performed using CliniMACs and the mean CD34+ dose was 20.1x106/kg. At day 0 either 108 CD3/kg (cohort 1, n=6) or 3x108 CD3/kg (cohort 2, n=14) T-cells from the CD34- fraction were infused with the graft. Mean follow up was 31.9 months.Results: In cohort 1, all patients engrafted and 2 developed high level donor mixed chimerism (both curative) in the myeloid and lymphoid lineages at last follow up. Two patients had Grade II acute GvHD and 1 had moderate chronic GvHD. In view of the slow immune reconstitution in this cohort, the T-cell addback dose was increased to 3x108/Kg in subsequent patients. In cohort 2, all patients achieved full donor haemopoiesis initially, 6/14 developed high levels of donor chimerism in both myeloid and lymphoid lineages later and 1/14 progressed with 10% donor T-cell engraftment but remains disease-free. The incidence of significant aGVHD was low (grade II n=4, no grade III or IV) and no patient developed cGvHD. Overall across both cohorts, 10 patients had viral reactivations and there were 5 deaths (3 viral complications, 1 pulmonary vasculopathy, 1 cGVHD lungs). The disease free survival at 2 years 7 months follow up was 70% which compares favorably with a previous cohort transplanted with unmanipulated BM as the stem cell source (Fig 1). Immune reconstitution was delayed (mean CD3 and CD19 counts at day 100 post-transplant was 245 x 109/L and 315 x 109/L) with similar kinetics in both cohorts (Fig 2), comparable to RIC transplant using unmanipulated BM. By 1 year post transplant 11/14 evaluable patients achieved normal CD3+T-cell numbers and 8/14 normal CD19+ B-cell counts.Conclusion: The use of megadose peripheral blood stem cells with T-cell addback in the mismatched unrelated donor transplant setting results in high rates of curative engraftment and a low incidence of acute and chronic GvHD following reduced toxicity conditioning. However, T-cell reconstitution remains delayed (presumably reflecting the effect of Alemtuzumab on the infused T-cells) with a high incidence of viral complications. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Successfull Engraftment and Clearance of Donor Specific Antibodies after Haploidentical Related Stem Cell Transplantation for an Adult Patient with Sickle Cell Disease

Introduction: Sickle cell disease (SCD) is one of the most common genetic disorders in the world and despite advances in best supportive care it remains a disease with high risk of morbidity and mortality. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative treatment modality. Reports of adults are limited because of the lack of suitable matched donors and the high treatment related toxicity (TRT) after conventional myeloablative conditioning regimen resulting from the accumulated disease specific end organ damage. Initial reports of non myeloablative conditioning regimen showed disappointing results because of the high risk of graft failure (GF) and disease recurrence. Recently, the development of reduced toxicity conditioning regimen (RTC) with lower TRT and the use of haploidentical family donors has widened the applicability of alloHSCT. Since SCD patients (pt) are highly alloimmunosized, donor HLA-specific antibodies (DSA) are often detectable and might compromise engraftment in HLA mismatched transplants.Material and Methods: We report a twenty two year old male pt with severe sickle cell-ß thalassemia and chronic blood transfusion related alloimmunization who received a family donor bone marrow alloHSCT from his haploidentical father. To reduce the risk of graft rejection, the preparative regimen consisted in a prephase-conditioning sequential immunoablation using two courses of a four day immunosuppressive treatment with fludarabine 40 mg/m2/d and dexamethasone 40 mg/d, six and three weeks before the start of the RIT conditioning regimen consisting of antithymocyte globuline (ATG, rabbit) 1.5 mg/kg from days -12 to -10; thiotepa 5 mg/kg on day -9; fludarabine 40 mg/m2 and intravenous busulfan 100 mg/kg from days -6 to -3. Graft versus host disease (GVHD) prophylaxis was provided by posttransplantation cyclophosphamide 50 mg/kg on day +3 and +4; cyclosporine and mycofenolate mofetil were started at day +5. The transplant work-up program included routine HLA antibody screening and prophylactic desensitization treatment with Rituxan combined with high dose immunoglobulin infusions after each cycle of immunoablation; additionally, plasmapheresis were performed at day -13 and -1, as well as one cycle of red blood cell exchange before the start of the RIT. Disease response was weekly measured by HbS levels using hemoglobin electrophoresis. Chimerism studies were done monthly by peripheral blood isolated CD3+ cells PCR analysis of variable number of nucleotide tandem repeats. DSA were examined using the luminex-based single antigen assay and MFI>=1000 were considered positive.Results: The time to neutrophil recovery over 500 x 103/mm3 and platelet recovery over 50 x 103/mm3 were 29 and 43 days respectively; transfusion independency was reached at day +36. No GF occurred with predominantly donor mixed chimerism (82%) at last follow-up. HbS levels (baseline 68%) continuously decreased after the start of the preparative regimen to < 1% at day +77. DSA were substantially reduced after desensitization treatment and importantly dropped down further after alloHSCT to undetectable levels. Of note, no increase of DSA posttransplantation was observed. With a follow up of 140 days, the pt developed no GVHD or early TRT.Conclusions: We presume that our preparative regimen approach in association with posttransplantation cyclophosphamide provides sufficient T-cell depletion and tolerance induction to enhance durable donor engraftment. The presence of DSA should not be a barrier to HLA haploidentical related alloHSCT. DisclosuresNo relevant conflicts of interest to declare.

Sequential Regimen of Clofarabine, Cytarabine and Reduced Intensity Conditioning (RIC) Prior to Allogeneic Stem Cell Transplantation (allo-SCT) for Acute Myeloid Leukemia (AML) in Primary Treatment Failure

Introduction. The prognosis of AML in primary treatment failure remains very poor. Salvage allo-SCT might be a potential therapeutic option in this setting. However, the limited feasibility of standard myeloablative conditioning (MAC) allo-SCT in these patients, lead to the development of the so-called “sequential” transplant approach (e.g. FLAMSA regimen combining both intensive chemotherapy and transplant conditioning within the same procedure - ). With this background, we conducted a phase 2 prospective trial to test the feasibility of a novel “sequential” approach, using busulfan and clofarabine.Study objective. This phase 2 prospective multicenter trial (ClinicalTRials.gov Identifier: NCT01188174) aimed to assess the efficacy (survival) and safety of a new “sequential“ conditioning regimen based on Clofarabine 30 mg/m2/d for 5 days, aracytine 1g/m2/d for 5 days and after a 3 days rest, cyclophosphamide 60 mg/Kg/d for 1 day, IV Busulfan 3.2 mg/Kg/d for 2 days and ATG (Thymoglobuline*) 2.5mg/Kg/d for 2 days in AML patients in primary induction failure (i.e. persistent leukemia after 2 courses of induction chemotherapy or persisting bone marrow hypoplasia following induction chemotherapy). For GVHD prophylaxis, patients received cyclosporine alone in case of a family donor, and cyclosporine+mycophenolate mofetil in case of an HLA-matched unrelated donor (MUD: 10/10 or 9/10).Patients and transplant characteristics. Between 2010 and 2013, a total of 24 patients were included. The median age of patients at time of allo-SCT was 47 (range, 20–55) years. At time of conditioning, all patients were confirmed having AML in primary induction failure. Karyotype was intermediate in 9 patients (38%) and adverse in 13 patients (54%), no patients had favorable karyotype and karyotype was missing in 2 patients (8%). Seven patients (29%) had secondary AML. The donor was an HLA-identical sibling donor in 15 cases (62%) and an HLA MUD in 9 cases (38%). Per protocol performance status was comprehensively assessed at time of inclusion. The Karnofsky score was 50%, 60%, 70%, 80%, 90%, and 100% in 2 (8%), 1 (4%), 2 (8%), 6 (25%), 8 (33%) and 5 (21%) patients, respectively.Results. ANC>500/μL was achieved at a median of 15 (range, 13–30) days after allo-SCT. The cumulative incidence of disease progression (RI) was 46% (95%CI, 25–64%) at one year and 59% (95%CI, 36–76%) at 2 years; while the cumulative incidence of NRM was 8% (95%CI, 1–24%) at one year and 13% (95%CI, 3–30%) at 2 years. The Kaplan-Meier estimate of overall (OS) was 54% (95%CI, 34–74%) at one year and 37% (95%CI, 17–56%) at 2 years. The Kaplan-Meier estimates of leukemia-free survival (LFS) were 46% (95%CI, 26–66%) at one year and 28% (95%CI, 9–46%) at 2 years.Conclusions. Results from this phase 2 prospective multicenter trial validated the safety and efficacy of a clofarabine-based sequential reduced-toxicity conditioning regimen. Such sequential regimen appeared to be safe with a 8% NRM at one year in high risk patients, and exhibits an efficient disease control both in very high risk refractory AML with a LFS of 46% at 1 year, warranting further investigations as part of phase 3 trials. DisclosuresMohty:Sanofi: Honoraria, Research Funding. Off Label Use: Off-label use of Clofarabine, was made as part of a sequential reduced intensity conditioning regimen.. Blaise:Sanofi: Honoraria, Research Funding.

Haploidentical Hematopoietic Stem Cell Transplantation (Haplo-SCT) with Pre-Transplant Immunosuppression (PTIS) and Post-Transplant Cyclophosphamide (Post-Cy) in Severe Thalassemia: Safe Approach and Excellent Disease Control

BackgroundCurrently, the thalassemia free survival rate after hematopoietic stem cell transplant (HSCT) is about 80-90% with either matched sibling or unrelated donor. However, the probability to find a suitable door is only 25-50%. Since most of these patients (pts) could not find the potential donor, we would like to investigate the haploidentical donor HSCT (Hapo-SCT) in thalassemia.Patients and MethodsBetween Jan 2013 and August 2014, 12 thalassemia patients (pts) underwent haplo-HSCT. Six subjects were male and 6 were female. The median age was 16 yrs (range; 2-22). Nine of 12 received stem cells from mother and 3 from father. Ten of 12 were high risk class 3. These high risk class 3 pts received hydroxyurea 20 mg/kg/d for at least 3 months prior to HSCT. All pts received 2 courses of pre-transplant immunosuppression (PTIS) consisting of fludarabine (Flu) 40 mg/m2/d together with dexamethasone (dex) 25 mg/m2/d for 5 days. After 2 courses of PTIS, all pts received a reduced-toxicity conditioning regimen consisting of thymoglobulin 1.5 mg/kg/d (d-11 to d-9), Flu 35 mg/m2/d i.v. (-7 to -2) each dose immediately followed by busulfan (Bu) 130 mg/m2once daily i.v. (d-7 to d -4) for pts > 10 years and 0.95-1.2 mg/kg every 6 hr (d-7 to d-4) for pts < 10 yrs. GVHD prophylaxis consisted of cyclophosphamide (Cy) 50 mg/kg/d (d +3 to d+4). Tacrolimus was given for 6 months to 1 yr started together with mycophenolate mofetil on d+5, the latter was quickly tapered after 2 months. T-cell repleted peripheral blood stem cells (PBSC) were given to all pts, targeting a CD34+ dose of 7-10 x 106cells/kg.ResultsEleven of 12 were engrafted with full donor chimerism (100%) while one pt suffered graft failure. However, this pt received second transplant on day +30 with minimal conditioning regimen and additional PBSC after which she achieved full donor chimerism. The median time to neutrophil engraftment was 18 days (range; 14 -22). Four pts had acute GVHD gr I, 2 grade II and 1 gr III. Only one had limited chronic GVHD. At this time, all 12 pts survive thalassemia-free and have sustained full donor chimerism (100%). Thalassemia free survial and overall survival rates are 100%. The median follow up time is 12 months (range 4-20).ConclusionHaploidentical HSCT for high risk thalassemia pts with our novel approach is safe and should be considered as modality to secure thalassemia-free survival with a low risk for graft rejection and treatment-related mortality. In view of our results, we suggest that all thalassemia pts even those with high risk class 3 features should be offred the chance for cure with HSCT. DisclosuresNo relevant conflicts of interest to declare.

Outcomes of Thalassemia Patients Undergoing Hematopoietic Stem Cell Transplantation by Using a Standard Myeloablative versus a Novel Reduced-Toxicity Conditioning Regimen According to a New Risk Stratification

Improving outcomes among class 3 thalassemia patients receiving allogeneic hematopoietic stem cell transplantations (HSCT) remains a challenge. Before HSCT, patients who were ≥ 7 years old and had a liver size ≥ 5 cm constitute what the Center for International Blood and Marrow Transplant Research defined as a very high–risk subset of a conventional high-risk class 3 group (here referred to as class 3 HR). We performed HSCT in 98 patients with related and unrelated donor stem cells. Seventy-six of the patients with age < 10 years received the more conventional myeloablative conditioning (MAC) regimen (cyclophosphamide, busulfan, ± fludarabine); the remaining 22 patients with age ≥ 10 years and hepatomegaly (class 3 HR), and in several instances additional comorbidity problems, underwent HSCT with a novel reduced-toxicity conditioning (RTC) regimen (fludarabine and busulfan). We then compared the outcomes between these 2 groups (MAC versus RTC). Event-free survival (86% versus 90%) and overall survival (95% versus 90%) were not significantly different between the respective groups; however, there was a higher incidence of serious treatment-related complications in the MAC group, and although we experienced 6 graft failures in the MAC group (8%), there were none in the RTC group. Based on these results, we suggest that (1) class 3 HR thalassemia patients can safely receive HSCT with our novel RTC regimen and achieve the same excellent outcome as low/standard-risk thalassemia patients who received the standard MAC regimen, and further, (2) that this novel RTC approach should be tested in the low/standard-risk patient population.

Reduced toxicity, myeloablative conditioning with BU, fludarabine, alemtuzumab and SCT from sibling donors in children with sickle cell disease

BU and CY (BU/CY; 200 mg/kg) before HLA-matched sibling allo-SCT in children with sickle cell disease (SCD) is associated with ~85% EFS but is limited by the acute and late effects of BU/CY myeloablative conditioning. Alternatives include reduced toxicity but more immunosuppressive conditioning. We investigated in a prospective single institutional study, the safety and efficacy of a reduced-toxicity conditioning (RTC) regimen of BU 12.8-16 mg/kg, fludarabine 180 mg/m(2), alemtuzumab 54 mg/m(2) (BFA) before HLA-matched sibling donor transplantation in pediatric recipients with symptomatic SCD. Eighteen patients, median age 8.9 years (2.3-20.2), M/F 15/3, 15 sibling BM and 3 sibling cord blood (CB) were transplanted. Mean whole blood and erythroid donor chimerism was 91% and 88%, at days +100 and +365, respectively. Probability of grade II-IV acute GVHD was 17%. Two-year EFS and OS were both 100%. Neurological, pulmonary and cardiovascular function were stable or improved at 2 years. BFA RTC and HLA-matched sibling BM and CB allo-SCT in pediatric recipients result in excellent EFS, long-term donor chimerism, low incidence of GVHD and stable/improved organ function.

Increasing Chimerism after Allogeneic Stem Cell Transplantation Is Associated with Longer Survival Time

Donor chimerism after allogeneic stem cell transplantation (allo-SCT) is commonly used to predict overall survival (OS) and disease-free survival (DFS). Because chimerism is observed at 1 or more times after allo-SCT and not at baseline, if chimerism is in fact associated with OS or DFS, then the occurrence of either disease progression or death informatively censors (terminates) the observed chimerism process. This violates the assumptions underlying standard statistical regression methods for survival analysis, which may lead to biased conclusions. To assess the association between the longitudinal post–allo-SCT donor chimerism process and OS or DFS, we analyzed data from 195 patients with acute myelogenous leukemia (n = 157) or myelodysplastic syndrome (n = 38) who achieved complete remission after allo-SCT following a reduced-toxicity conditioning regimen of fludarabine/intravenous busulfan. Median follow-up was 31 months (range, 1.1 to 105 months). Fitted joint longitudinal-survival time models showed that a binary indicator of complete (100%) donor chimerism and increasing percent of donor T cells were significantly associated with longer OS, whereas decreasing percent of donor T cells was highly significantly associated with shorter OS. Our analyses illustrate the usefulness of modeling repeated post–allo-SCT chimerism measurements as individual longitudinal processes jointly with OS and DFS to estimate their relationships.

Fludarabine, cytarabine, granulocyte colony‐stimulating factor and melphalan (FALG with L‐PAM) as a reduced toxicity conditioning regimen in children with acute leukemia

The conventional conditioning regimen for patients with leukemia prior to allogeneic stem cell transplantation is myeloablation to eradicate residual leukemic cells and host immunocompetent cells. This helps prevent leukemic relapse as well as rejection after transplantation. A myeloablative conditioning regimen with busulfan (BU) or total body irradiation (TBI) is effective for eradication of leukemic cells but is also associated with significant toxicities in the acute or late phase in pediatric patients. In an effort to minimize these adverse effects, we conducted bone marrow transplantation (BMT) from unrelated volunteer donors using a conditioning regimen without BU or TBI. Ten patients with acute leukemia in first or second remission were given a "non-BU, non-TBI conditioning regimen," which consisted of fludarabine (FLU), cytarabine (CA), and melphalan (L-PAM) after FLAG combined with L-PAM. Engraftment was obtained in all patients, and two patients died of relapse. Eight of 10 patients have been disease-free for a median of 126 months (116-142) after transplantation. The overall survival, event-free survival, relapse rate, and treatment-related mortality were 80.0%, 80.0%, 20.0% and 0.0%, respectively. In female patients, spontaneous menstruation with normal luteinizing hormone (LH), follicle stimulating hormone (FSH), and estradiol (E2) levels was observed in all four patients at post-pubertal age. This conditioning regimen of FLAG combined with L-PAM (which did not contain BU and TBI) was associated with good outcomes and minimal late adverse effects in children with acute leukemia who have undergone allogeneic BMT from unrelated volunteer donors.

Allogeneic transplantation strategies including haploidentical transplantation in sickle cell disease

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy. Despite antenatal counseling and neonatal screening programs implemented in higher income countries, SCD is still associated with multiple morbidities and early mortality. To date, the only curative approach to SCD is hematopoietic stem cell transplantation, but this therapy is not yet established worldwide. The registries of the European Blood and Marrow Transplant (EBMT) and the Centre for International Blood and Marrow Transplant Research (CIBMTR) account, respectively, for 611 and 627 patients receiving transplantations for SCD. Most of these patients were transplanted with grafts from an HLA-identical sibling donor. The main obstacles to increasing the number of transplantations are a lack of awareness on the part of physicians and families, the absence of reliable prognostic factors for severity, and the perceived risk that transplantation complications may outweigh the benefits of early transplantation. Results show that more than 90% of patients having undergone an HLA-identical sibling transplantation after myeloablative conditioning are cured, with very limited complications. Major improvement is expected from the use of new reduced-toxicity conditioning regimens and the use of alternative donors, including unrelated cord blood transplantations and related haploidentical bone marrow or peripheral blood stem cell transplantations.

Steroid Responsive T-Cell Mediated Pure Red Cell Aplasia Following Allogeneic Hematopoietic Stem Cell Transplantation

Pure red cell aplasia (PRCA) is an unusual complication following allogeneic hematopoietic stem cell transplantation (HSCT), the true incidence of which is not known. Almost all cases reported in the literature describe major ABO-incompatibility between the recipient and the donor as the major risk factor for this complication. Delayed recovery of reticulocyte counts and hypoplasia of erythroblasts in the marrow is attributed to incompatible hemagglutinins in recipients. There are reports of successful treatment of PRCA using different strategies include rapid tapering of calcineurin inhibitors, corticosteroids, donor lymphocyte infusion, rituximab, and/or plasma exchange. Additional causes of PRCA following allogeneic HSCT include parvovirus B19 infection and graft-versus-host disease (GVHD). The pathogenesis of PRCA in parvovirus infection is thought to be viral-mediated suppression of erythroid precursors in the bone marrow and this is due to the tropism of this virus for erythroid progenitor cells. Nonmyeloablative and reduced intensity conditioning regimens have been reported to have an increased risk of PRCA due to persistence of recipient lymphocytes. Here we report two cases of PRCA following allogeneic HSCT from major ABO mismatched donors. Both cases were correlated with the presence of a T-cell clone in the peripheral blood and bone marrow, and there was complete resolution of anemia with a short course of steroid treatment, as well as disappearance of the T-cell clone. Patient # 1 – A 24 year old female of Mediterranean descent underwent an HLA- 8/10 matched and major ABO-mismatched sibling donor bone marrow transplant for Sickle-Beta Thalassemia. She received a myeloablative but reduced toxicity conditioning regimen consisting of busulfan 16mg/kg, fludarabine 140mg/m2, cyclophosphamide 105mg/kg, and alemtuzumab 52mg/m2. Her immediate post-transplant course was relatively benign and significant for a mild CMV colitis which responded with resolution after treatment with anti-viral therapy. Her red cell transfusion needs had significantly decreased to every four weeks by day 130. However, at day 146 from HSCT, she started requiring red cell transfusions every two weeks, with a drop in the reticulocyte count to 0.6%. No antibodies were detected, and the patient was negative for parvovirus B19 and did not have any evidence of GVHD. However, her bone marrow showed an marked erythroid hypoplasia, and was positive for a T-cell clone with gamma chain gene rearrangement in the T-cell receptor. Due to a new onset of transfusion need, she was treated with a short course of steroids with an excellent response and disappearance of the T-cell clone from peripheral blood. She remained on immunosuppression during this entire period with a calcineurin inhibitor. Patient# 2 – A 10 year old Hispanic girl underwent a 10/10 HLA-matched and major ABO-mismatced sibling donor bone marrow transplant for idiopathic acquired severe aplastic anemia. Her preparative regimen consisted of 200 mg/kg of cyclophosphamide and 16mg/kg of rabbit-anti-thymocyte globulin. Her immediate post-transplant course was complicated by E.coli bacteremia. She had prompt engraftment and became transfusion independent on day 86. A cyclosporine taper was initiated at day 100 but held at day 119 when anemia was first noted. Peripheral blood showed a T-cell clone with gamma and beta chain gene rearrangement. She was started on a moderate dose of steroids with a good response, and has been tapered down to physiologic replacement dose of steroids with normal Hb and transfusion independence. With the resolution of anemia, the gamma chain gene rearrangement is not seen in the T-cell clonality assay, however, the beta chain gene rearrangement persists. To our knowledge, this is the first report of a T-cell mediated PRCA following allogeneic HSCT. Moreover, the PRCA was steroid responsive and not associated with GVHD in both the patients. Disclosures:No relevant conflicts of interest to declare.

Low-Dose 5-Azacytidine Combined With Donor Lymphocyte Infusions (DLI), An Effective Outpatient Treatment Of AML/MDS Relapse After Allografting, Can Induce Long-Term Remissions: An Experience Of 72 Patients

BackgroundThe DNA hypomethylating agents 5-azacytidine (aza) and decitabine are a new treatment option for AML/MDS pts relapsing after allografting. Cancer/testis antigens are upregulated in vitro and in vivo by these drugs (Goodyear et al., Blood 2010, Almstedt et al., Leuk. Res. 2010), hypothetically sensitizing (“priming”) malignant cells to DLIs. In 2006 we initiated a program of administering aza (100 mg/day) for 3 consecutive days, followed whenever possible by DLI 7 days after the last aza injection (repeated every 3-4 weeks). Of 26 pts treated thus, more than 50% achieved at least temporary disease control, with 4 pts achieving complete remissions (CRs) of >12 months duration at time of reporting (Lübbert et al., BMT 2009). We now updated the results of these 26 pts and report on the further 46 pts treated on this program. Patients and MethodsBetween 10/2006 and 05/2013, 72 pts (median age 62 years, range 20–75, 46 male, 26 female) with hematological relapse after allografting were treated with aza and, if at all feasible, with DLI as described above. A 5-day schedule of 100 mg/m2 aza daily as starting dose was introduced in 2009 for pts with higher leukemic load. Diagnoses were AML (n=62), MDS (n=6), CMMoL (n=2), acute mast cell leukemia and blastic plasmacytoid dendritic cell neoplasm (1 each). Of 68 pts with informative cytogenetics, 44 had intermediate-2 or adverse cytogenetics according to ELN Guidelines. Sixty pts had received fludarabine-based reduced-toxicity conditioning regimens (mostly FBM), 12 had received myeloablative conditioning; 23 pts had a HLA-matched sibling donor, 47 pts an unrelated donor and 2 pts a syngeneic sibling donor. Median duration from transplant to first day of aza was 289 days (range, 59 to 2133), 48,19 and 2 pts were in 1st, 2nd or 3rd hematologic relapse, respectively, at start of aza. Two pts had only mixed chimerism, one had only extramedullary disease at 1st relapse. Median % of blasts before aza was 4 % (range 0 to 91) in peripheral blood and 25 % (range 0 to 100) in bone marrow. Response criteria (for CR, temporary disease control or treatment failure) were applied as previously described. Uni- and multivariate analyses were performed. Results47 pts (65 %) and 18 pts (25 %) received a 3-day or 5-day course of aza, respectively, as starting dose. In 3 (4 %) and 4 pts (6 %), initial dosing was limited to 2 and 4 days, respectively. A total of 189 courses of aza were administered (median of 2.7 courses, range 1 to 10). 65/72 pts (90 %) also received DLIs, 41/72 (57%) already prior to first aza. Only 7 pts developed acute GvHD after DLI treatment. Clinically relevant neutropenic infections not associated with disease progression developed in 4 pts, in one of them leading to fatal sepsis. 39 pts (54 %) benefited from the treatment, with CR in 7 pts (9.7%), in 2 of them now lasting more than 5 yrs. Thirty-two pts (44 %) had temporary disease control with stable mixed chimerism (median duration 71 days, range 31-380), with 2 pts converting to complete donor chimerism lasting 146 and 380 days, respectively. The median survival from start of aza was 108 days. Nine pts are alive at the time of this report. Twenty-one pts proceeded to subsequent transplant, 4 of them (19%) are presently alive. Among 10 predictive factors, 5 were significant at p<0.1 and thus subjected to a multivariate analysis (Cox model; Table 1). Peripheral blood blasts <1 % retained their predictive value for better overall survival (32.7 vs. 14.7 weeks, p=0.03).Table 1Cox-Regression for univariate predictive (p<0.1) baseline parametersHR95% CI for HRp-valueDLI prior to first 5-azacytidineYes1-0.09No1.61[0.92, 2.81]blood stem cell donorUnrelated1-0.18Related0.62[0.31, 1.25]weeks from transplant to relapse>=361-0.08<361.72[0.94, 3.15]peripheral blood blasts<1%1-0.03>=1%1.98[1.07, 3.66]Donor age<=40 years1-0.83>40 years0.93[0.50, 1.75] ConclusionIn an extended cohort of pts we could confirm our previous results of clinical activity of this approach. Notably, there are long-term remitters after this well-tolerated outpatient treatment, which appears particularly effective in pts without peripheral blood blasts. Recurrent responses to the aza / DLI combination in pts who had progressed under DLI-only treatment support the “priming” concept whereby hypomethylating agents can sensitize malignant cells to other biological or cellular therapies, thus acting as so-called biological response modifiers. Disclosures:Off Label Use: 5-azacytidine, immunomodulation.

The current role of T cell depletion in paediatric stem cell transplantation

Haematopoeitic stem cell transplantation (HSCT) is a curative procedure for children with malignant and non-malignant haematological disease as well as an expanding number of inherited disorders. Most patients lack a human leucocyte antigen-matched related donor, making alternative donors, such as closely matched unrelated donors, unrelated umbilical cord blood donations and haploidentical donors, necessary choices. T cell depletion (TCD) has been employed for over 30 years to reduce the risk of graft-versus-host disease (GvHD) associated with non-genoidentical HSCT. However, until recently overall survival had not improved with TCD due to increased rates of graft failure, disease relapse and delayed immune reconstitution. Recent advances in graft manipulation and reduced toxicity conditioning regimens have offered renewed hope, particularly for children undergoing haploidentical HSCT, where encouraging results have been achieved using negative depletion techniques to retain beneficial accessory cells, which speed immune reconstitution and reduce disease relapse. Translational work building on megadose CD34(+) selected grafts, including pathogen-specific immunotherapy, suicide gene therapy and other adoptive cellular immunotherapies, has also offered improved outcomes for such patients.

Pretransplant Immunosuppression followed by Reduced-Toxicity Conditioning and Stem Cell Transplantation in High-Risk Thalassemia: A Safe Approach to Disease Control

Patients with class 3 thalassemia with high-risk features for adverse events after high-dose chemotherapy with hematopoietic stem cell transplantation (HSCT) are difficult to treat, tending to either suffer serious toxicity or fail to establish stable graft function. We performed HSCT in 18 such patients age ≥7 years and hepatomegaly using a novel approach with pretransplant immunosuppression followed by a myeloablative reduced-toxicity conditioning regimen (fludarabine and i.v. busulfan [Flu-IV Bu]) and then HSCT. The median patient age was 14 years (range, 10 to 18 years). Before the Flu-IV Bu + antithymocyte globulin conditioning regimen, all patients received 1 to 2 cycles of pretransplant immunosuppression with fludarabine and dexamethasone. Thirteen patients received a related donor graft, and 5 received an unrelated donor graft. An initial prompt engraftment of donor cells with full donor chimerism was observed in all 18 patients, but 2 patients developed secondary mixed chimerism that necessitated withdrawal of immunosuppression to achieve full donor chimerism. Two patients (11%) had acute grade III-IV graft-versus-host disease, and 5 patients had limited chronic graft-versus-host disease. The only treatment-related mortality was from infection, and with a median follow-up of 42 months (range, 4 to 75), the 5-year overall survival and thalassemia-free survival were 89%. We conclude that this novel sequential immunoablative pretransplantation conditioning program is safe and effective for patients with high-risk class 3 thalassemia exhibiting additional comorbidities.

Novel Reduced Toxicity Conditioning Regimen for Older Severe Thalassemia Patients: Sequential Immunoablative Concept

Novel Reduced Toxicity Conditioning Regimen for Older Severe Thalassemia Patients: Sequential Immunoablative Concept

Fludarabine, IV Busulfan and Antithymocyte Globulins-Based Reduced-Toxicity Conditioning Regimen Prior to Allogeneic Stem Cell Transplantation (allo-SCT): Results of a Multicenter Prospective Trial

AbstractAbstract 1926 Introduction.In the last decade, the so-called reduced intensity or reduced-toxicity conditioning (RTC) regimens prior to allo-SCT have emerged as an attractive modality to decrease allo-SCT-related toxicities and non-relapse mortality (NRM). In the context of RTC allo-SCT, IV Busulfan proved to be a key drug, because of its safety profile and potential anti-tumor activity that can allow for early disease control while waiting for the immune-mediated GVL effect. Study objective.This phase 2 prospective multicenter trial (ClinicalTrials.gov Identifier:NCT00841724) aimed to assess at one year the efficacy and safety of a “submyeloablative” conditioning regimens based on IV Busulfan 130mg/m2/d (administered as a single daily infusion over 3 hours) for 3 days (total dose equivalent to 9.6 mg/Kg), Fludarabine 30mg/m2/d for 5 days, and ATG (Thymoglobuline*) 2.5mg/Kg/d for 2 days (the “FB3” regimen) in patients with high risk hematological malignancies candidate for allo-SCT but not eligible for a standard myeloablative conditioning regimen. For GVHD prophylaxis, patients received cyclosporine alone in case of a family donor, and cyclosporine+mycophenolate mofetil in case of an HLA-matched unrelated donor (MUD: 10/10 or 9/10). Patients and transplant characteristics.Between 2008 and 2011, a total of 80 patients were included (47 males, 59%). The median age of patients at time of allo-SCT was 53 (range, 25–64) years. Diagnoses included: ALL/AML/biphenotypic acute leukemia (n=5; n=26; n=1; 40%); MDS/MPS (n=6; 8%); CLL (n=3; 4%); NHL and HD (n=24; 30%); and myeloma (n=15; 18%). At time of conditioning, 39 patients (48%) were in first CR, 14 patients (18%) were in CR2/CR3, and 27 patients (34%) were in more advanced disease phases. The donor was an HLA-identical sibling donor in 28 cases (35%) and an HLA MUD in 52 cases (65%). The stem cell source was G-CSF-mobilized PBSC in 77 cases (96%) and unmanipulated bone marrow in 3 cases (4%). Per protocol, comorbidities and performance status were comprehensively assessed at time of inclusion. The Karnofsky score was 70%, 80%, 90%, and 100% in 4 (5%), 11 (14%), 28 (35%), and 37 (46%) patients, respectively. At time of transplant, 54 patients (68%) had at least one comorbidity, while 26 patients (32%) did not have any. In this cohort, the HCT comorbidity index developed previously by Sorror et al. was 0, 1 or 2 and >2 in 27 (34%), 21 (26%) and 32 (40%) patients, respectively. Results.All patients but one engrafted. ANC>500/μL was achieved at a median of 15 (range, 10–23) days after allo-SCT, and 98% of patients had platelets >50.000/μL by day 60 after transplantation (of whom none was below 20.000/μL at any time point). The cumulative incidences of grade 2–4 and grade 3–4 acute GVHD were 32% (95%CI, 21–43%) and 9% (95%CI, 4–18%), respectively. The cumulative incidence of relapse/disease progression (RI) at one year was 26% (95%CI, 17–36%), while the cumulative incidence of NRM was 10% (95%CI, 5–18%) at one year. The Kaplan-Meier estimates of overall (OS) and progression-free survival (PFS) at one year were 71% (95%CI, 61–81%) and 64% (95%CI, 53–74%), respectively. In terms of prognostic factors for outcome, patient age, diagnosis, donor type, gender, presence or absence of comorbidities and the HCT comorbidities index, did not have any statistically significant impact on NRM, RI, PFS and OS. Only a Karnofsky score <90% at time of allo-SCT had a negative impact on OS (47% vs. 77%; p=0.008), while only disease status (CR1 vs. other) impacted RI (p=0.02). Conclusions.Results from this phase 2 prospective multicenter trial validated the safety and efficacy of a so-called reduced-toxicity conditioning regimen which could overcome the deleterious impact of comorbidities since no statistically significant impact of the HCT comorbidity index on outcome could be shown. Such FB3 regimen appears to be safe with a 10% NRM at one year in high risk patients, and exhibits an efficient disease control both in myeloid and lymphoid malignancies, warranting further investigations as part of phase 3 trials. Disclosures:Mohty:Pierre-Fabre: Consultancy, Honoraria, Speakers Bureau. Blaise:Genzyme/Sanofi: Honoraria, Research Funding; Pierre Fabre: Honoraria, Research Funding; Otsuka: Honoraria.

Secondary malignancies after allogeneic stem-cell transplantation in the era of reduced-intensity conditioning; the incidence is not reduced

Secondary malignancies are well established complication in long-term survivors after allogeneic stem-cell transplantation (SCT) with myeloablative conditioning (MAC). Fludarabine-based reduced-intensity (RIC) and reduced-toxicity conditioning (RTC) regimens are increasingly used in the last decade; however, due to limited long-term follow-up, there is no data on secondary malignancies in this setting. The records of 931 consecutive patients given allogeneic SCT with MAC (n=257), RIC (n=449) or RTC (n=225), in a single institution over a 13-year period, were reviewed. Twenty-seven patients had secondary malignancy, diagnosed a median of 43 months (7 months-11.5 years) after SCT. The 10-year cumulative incidence was 5.6% (95% confidence interval (CI), 3.6-8.7), twice the expected rate in matched normal population. The incidence was 1.7, 7.4 and 5.7% after MAC, RIC and RTC, respectively (P=0.02). Multivariate analysis identified fludarabine-based conditioning (hazard ratio (HR) 3.5, P=0.05), moderate-severe chronic graft-versus-host disease (HR 2.8, P=0.01) and diagnosis of chronic myeloproliferative or non-malignant disease (HR 0.2, P=0.04) as risk-factors for secondary malignancy. The related 10-year mortality rate was 2.4% (95% CI, 1.0-5.4). In conclusion, the risk of secondary malignancies is not reduced and is even possibly increased in the era of fludarabine-based RIC/RTC. Patients and physicians should be aware of this association and life-long cancer screening is required for all transplant survivors.