ALBERT

Description: Multidrug-resistant bacterial pathogens (MRP) such as extended-spectrum beta-lactamase producing enterobacteriaceae (ESBL), vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococcus aureus (MRSA) are an emerging challenge in allogeneic hematopoietic cell transplantation (HCT). However, to our knowledge there are no data in the existing literature on the prevalence of MRP and of the impact of these multidrug-resistant pathogens on the outcome after allogeneic HCT. Thus, it was the purpose of this study to systematically analyze the issue of MRP in patients who underwent allogeneic HCT. PATIENTS AND METHODS: From 06/2010 to 12/2013 a total number of 72 (F: n=23; M: n=49) consecutive patients who received the first allogeneic HCT at our institution were retrospectively analyzed. The underlying diseases were AML (n=44), ALL (n=5), CML (n=4), MPN (n=2), lymphoma (n=5), MDS (n=9), and multiple myeloma (n=3). The conditioning regimen was myeloablative in 23 patients and reduced intensity in 49 patients. Patients were transplanted with peripheral blood stem cells (n=69) or bone marrow (n=3) from matched siblings (n=19), matched unrelated (n=45), mismatched (n=5) or haploidentical donors (n=3). As baseline investigation before commencing with the conditioning all patients underwent a comprehensive screening for MRP, i.e. ESBL, VRE and MRSA. For that reason swabs from nose, throat, axilla, urethra and anus as well as stool and urine were collected. The same screening was performed at discharge from hospital after allogeneic HCT and in case of a new admission into our institution. In addition routine microbiological investigations such as bacterial cultures from blood, urine, swabs, stool or central venous catheters were performed whenever clinically needed. Multidrug-resistant gram negative bacteria were categorized as 4MRGN (resistant to cephalosporins, piperacillin, fluorochinolones and to carbapenems) or as 3MRGN (resistant to 3 of these 4 antimicrobial drug groups). The primary endpoint of this analysis was day 100 non relapse mortality (NRM). Secondary endpoints were NRM and overall survival (OAS) two years post HCT. RESULTS: 23 out of 72 patients (32%) were colonized by multidrug-resistant bacterial pathogens (MRP+ group) either at baseline (baseline MRP+ group, n=13, 18%) or at any other time point until day 100 post transplantation. Four patients were positive for two MRP either simultaneously at baseline (n=1) or at different time points (n=3). Detected MRP (n=27) were as follows: 3MRGN Escherichia coli or Klebsiella pneumonia (n=11), 4MRGN Pseudomonas aeruginosa (P. aeruginosa, n=4), 3MRGN P. aeruginosa (n=2), 4MRGN Stenotrophomonas maltophilia (n=1), 3MRGN Citrobacter freundii (n=1), VRE (n=7) and MRSA (n=1). Out of these 23 patients 7 patients developed an infection with MRP after HCT: Septicemia with 3MRGN Escherichia coli (n=3), septicemia with 3MRGN Klebsiella pneumonia (n=1), septicemia with P. aeruginosa (4 MRGN n=2, 3MRGN n=1) and one patient with VRE septicemia and 4MRGN P. aeruginosa pneumonia. Out of the 4 patients with multidrug-resistant P. aeruginosa infection three died transplant related (two of these patients had been already colonized with 4MRGN P. aeruginosa at baseline). However, 2-year OAS of MRP colonized versus non-colonized patients was essentially the same (66.6% versus 63.0%, median follow up 23.8 months range 7.0 to 48.0 months). Day 100 NRM was higher in the baseline MRP+ group and in the entire MRP+ group in comparison with non-multidrug-resistant bacterial pathogens colonized patients (23.1% and 17.4% versus 10.2%, not statistically significant [ns]). Data for 2 year NRM were 32.7%, 22.2% and 17.1% (ns), respectively. The increased NRM of MRP+ patients was mainly due to the high NRM of patients infected by multidrug resistant P. aeruginosa. CONCLUSIONS: Colonization or infection with 3MRGN gram negative non-P. aeruginosa enterobacteriaceae or by VRE has no negative impact on the outcome after allogeneic HCT. Thus allogeneic HCT of patients colonized by MRP is feasible. However, patients colonized by multidrug-resistant P. aeruginosa seem to have a dismal outcome. Allogeneic HCT of these patients should be considered with care. We therefore suggest to include screening for MRP in the pretransplant recipient work up particularly to identify patients colonized by multidrug-resistant P. aeruginosa. Disclosures No relevant conflicts of interest to declare.

Description: Steroid refractory intestinal acute Graft versus Host Disease (aGvHD) is a mayor complication after allogeneic hematopoietic cell transplantation. Survival rate of severe intestinal aGvHD is low. No therapy has been proven to increase the survival rate in steroid refractory aGvHD so far. A promising strategy is the use of pentostatin, a purine nucleotide analogue and inhibitor of adenosine deaminase, which is known to decrease function and number of lymphocytes. Here we report the six year follow-up of a pilot study on salvage therapy of aGvHD by pentostatin. We treated 18 patients with steroid refractory intestinal aGvHD stage III or IV with Pentostatin (8 female and 10 male patients). The mean age was 45 (range: 25–61 years). The underlying diseases were ALL (4), AML (10), Multiple Myeloma (2), Hodgkin’s Disease (1) and CML (1). Eight patients were allografted with HLA-identical sibling donors, three with related donors with a single HLA class I mismatch, seven with matched unrelated donors. All patients were allografted with peripheral blood stem cells. As GvHD prophylaxis ciclosporine A in combination with mycophenolate mofetil or methotrexate were used. Eleven patients had aGvHD stage III, seven stage IV. All patients had a severe gastrointestinal-tract involvement (grade III or IV). After failure of steroid treatment (prednisolone 〉2 mg/kg for at least 3 days) pentostatin was applied as a salvage therapy (1 mg/m2 for three consecutive days). Eight patients received between one and three further courses of pentostatin every three to four weeks. Therapy was well tolerated. No severe neutropenia was observed. Except one case of hemolytic uremic syndrome (HUS) no impairment of renal function was observed. Eleven patients achieved a complete, five a partial remission of aGvHD. Time until a clinical improvement could be observed was 12–14 days. Two patients died before day 12 without improvement of GvHD symptoms. Seven patients (39%) are alive (510–2060 days post first cycle of pentostatin), two with extensive chronic GvHD. All one-year-survivors stayed alive. Eleven patients died (two due to relapse of leukemia, nine transplant related [1 x interstitial pneumonitis, 1 x pneumonia, 1 x chronic GvHD, 4 x aGvHD and multiple organ failure (MOF), 1 x parvo B19 infection and MOF, 1 x HUS and MOF]). In conclusion, in this pilot study pentostatin has been demonstrated to be a highly effective and well tolerated drug for salvage therapy of steroid refractory acute GvHD with intestinal involvement. Moreover, compared with earlier studies on steroid refractory aGvHD a high rate of long term survivors could be observed. By a multicenter prospective randomised study we are currently investigating whether pentostatin can improve the outcome in steroid refractory intestinal aGvHD.

Description: In patients with relapsed or refractory (r/r) Acute Myeloid Leukemia (AML), allogeneic Hematopoietic Stem Cell Transplantation (HSCT) is considered to be the only treatment providing long-term disease control for fit patients. The BRIDGE trial studied the safety and efficacy of a clofarabine-based salvage therapy prior to HSCT in patients with r/r AML. Here, we report the long-term follow up of this Phase II, multi-center, Intent-To-Transplant study and the impact of comorbidity on outcome. Eighty-four patients with a median age of 61 years (range 40 - 75) were enrolled. Patients were scheduled for at least one cycle of salvage therapy with CLARA (clofarabine 30 mg/m2 and cytarabine 1 g/m2, days 1-5). Chemo-responsive patients with a donor received HSCT after first CLARA. In the event of a prolonged donor search, HSCT was performed as soon as possible. The conditioning regimen consisted of clofarabine 30 mg/m2, day -6 to -3, and melphalan 140 mg/m2 on day -2. The ECOG score, hematopoietic cell transplantation-specific comorbidity index (HCT-CI) and Cumulative Illness Rating scale (CIRS) were obtained at study enrolment as well as prior to HSCT. Sixty-seven percent of the patients received HSCT within the trial. After a median follow up of 40months (95% CI, 38-49 months), the estimated 4-year OS (Figure 1) for all enrolled patients was 38% (95% CI, 28-50%) and Disease-Free Survival for transplanted patients was48% (95% CI, 36-64%). The CIR at four years was 30% (95% CI, 17-43%) and the NRM 22% (95% CI, 10-33%).Those patients who received an allogeneic HSCT within the trial had a median HCT-CI at the time of study enrollment of 1 (range, 0 - 6) compared to a median of 2 (range, 0 - 6) for those who did not proceed to allogeneic HSCT (p = .17). Corresponding figures for the CIRS were a median of 2 (range, 0 - 9) compared to 4 (range, 0 - 8) (p = .09). The median ECOG score was 1 (range, 0 - 3) in both groups. Compared to the time point of study enrollment, both the HCT-CI as well as the CIRS increased to a median of 2 (observed range of score, 0 - 7) and a median of 4 (observed range of score, 0 - 12), respectively, at the time of start of the conditioning regimen. This was almost exclusively due to an increase in infectious complications (Figure 2). Inmultivariate analysis, both the baseline HCT-CI and the ECOG score had a statistically significant impact with a HR of 1.22 (p = .025) and 1.72 (p = .001), respectively, on OS. Using a clofarabine-based salvage therapy combined with early allogeneic HSCT we were able to achieve good long-term results for patients with r/r AML. In this cohort, both the HCT-CI and the ECOG score gave prognostic information on OS, showing feasibility of comorbidity evaluation at the time of diagnose of r/r AML. Figure 1 OS of all enrolled patients Figure 1. OS of all enrolled patients Figure 2 Changes of the HCT-CI at baseline to HSCT Figure 2. Changes of the HCT-CI at baseline to HSCT Disclosures Middeke: Sanofi: Honoraria. Rösler:Janssen: Consultancy, Other: Travel/Accommodation/Expenses. Thiede:AgenDix: Employment, Other: Ownership. Schetelig:Sanofi: Honoraria.

Description: Background: In relapsed or refractory acute myeloid leukemia (AML), long-term disease-free survival may only be achieved with allogeneic hematopoietic stem cell transplantation (HSCT). Within the BRIDGE Trial, the safety and efficacy of a clofarabine salvage therapy as a bridge to HSCT was studied. Here, we report long-term survival data and the impact of donor availability at the time of study enrollment. The BRIDGE trial (NCT 01295307) was a phase II, multicenter, intent-to-transplant study. Patients and Methods: Between March 2011 and May 2013, 84 patients with relapsed or refractory AML older than 40 years were enrolled. Patients were scheduled for at least one cycle of induction therapy with CLARA (clofarabine 30 mg/m2 and cytarabine 1 g/m2, days 1-5). Patients with a donor received HSCT in aplasia after first CLARA. In case of a prolonged donor search, HSCT was performed as soon as possible. The conditioning regimen consisted of clofarabine 30 mg/m2, day -6 to -3, and melphalan 140 mg/m2 on day -2. In patients with partially matched unrelated donors, ATG (Genzyme) at a cumulative dose of 4.5 mg/kg was recommended. GvHD prophylaxis consisted of CsA and mycophenolate mofetil. Results: Forty-four patients suffered from relapsed AML and 40 patients had refractory disease. The median patient age was 61 years (range 40 – 75). According to the current ELN risk stratification 17% of pts were classified as favorable risk, 35% as intermediate I, 17% as intermediate II and 20% as adverse risk. The overall response rate assessed at day 15 after start of CLARA was 80% (defined as at least a marked reduction in BM blasts or BM cellularity and absence of blasts in the peripheral blood) with 31% of patients having less than 5% BM blasts at that time. Seventeen patients did not respond to CLARA, and were subsequently treated off-study. Due to early death, three patients were not evaluable for treatment response. Overall, 66% of the patients received HSCT within the trial. Donors were HLA-identical siblings in eight cases (14%), HLA-compatible unrelated donors in 30 cases (55%) and unrelated donors with one mismatch in 17 cases (31%). Treatment success was defined as complete remission (CR), CR with incomplete recovery (CRi) or CRchim (BM donor chimerism 〉95% and absolute neutrophil count 〉0.5/nL) on day 35 after HSCT. Treatment success was achieved in 61% of the patients. With a median follow up of 25 months, the OS for all enrolled patients at two years was 42% (95% CI, 32% to 54%). (Figure 1) The Leukemia-free survival at two years for those 51 patients who achieved the primary endpoint was 52% (95% CI, 40% to 69%). (Figure 2) At the time of enrollment, 14% of patients had a related donor and 33% had an unrelated donor available. In 46% of the patients, donor search was initiated at the time of enrollment. For 7% of patients, donor search was unsuccessful prior to enrollment and reinitiated. The OS at 2 years for patients with a related or an unrelated donor available was 75% (95% CI, 54% to 100%) and 47% (95% CI, 31% to 71%), respectively, while it was 29% (95% CI, 18% to 48%) for patients for whom donor search was initiated at time of enrollment (p = .09). Conclusions: Salvage therapy with CLARA, and subsequent conditioning with clofarabine and melphalan prior to allogeneic HSCT, provides good anti-leukemic activity in patients with relapsed or refractory AML. Fast unrelated donor search and work up, with conditioning in aplasia allowed a high rate of successful HSCTs. The leukemia-free survival for this group of elderly, high risk AML patients is very promising. Figure 1 Figure 1. Overall survival for all patients, n=84 Figure 2 Figure 2. Leukemia-free survival for all patients with primary treatment success, n=51 Disclosures Middeke: Genzyme: Speakers Bureau. Off Label Use: Clofarabine for AML. Schetelig:Genzyme: Research Funding; DKMS German Bone Marrow Donor Center: Employment.

Description: Introduction The extent of systemic iron overload (SIO), quantified by magnetic resonance imaging (MRI), has been associated with adverse outcome in some studies in MDS and AML patients undergoing allogeneic stem cell transplantation (allo-SCT), whereas others were unable to demonstrate a significant impact. It has been hypothesized that the release of reactive iron species such as labile plasma iron (LPI) during the transplant procedure mediates iron-associated cellular toxicity by catalyzing the generation of oxygen radicals and fostering the growth of microbial agents. The association between SIO, the occurrence of LPI and the outcome after allo-SCT has not been prospectively studied so far. Patients, Material and Methods This was a Geman-Austrian prospective multicenter observational trial in 133 patients with AML or MDS undergoing allo-SCT between 2013 and 2015 (NCT01746147). Inclusion criteria were either having a ferritin above 500 ng/ml or having received more than 10 red blood cell concentrates. Liver iron content (LIC) was determined by MRI prior to and on day +100 and day +360 after allo-SCT. Enhanced labile plasma iron (eLPI) was measured using the Ferros eLPI Kit (Afferix) prior to, during and after conditioning and an eLPI above 0.4 was defined as positive. Results At the time of analysis 21 MDS and 90 AML patients were evaluable for LIC. The median age of the cohort was 61 years (range: 21 to 75 years) and the majority (80.2 %) received reduced intensity conditioning regimens. Median LIC prior to conditioning was 110 µmol/g and 45.9 % had a LIC above the pre-specified threshold of 125 µmol/g (7 mg/g) indicating SIO. A LIC 〉=125 µmol/g was associated with a significantly increased cumulative incidence (CI) of early (day +100) NRM (19.8 % vs. 6.8 % p = 0.034), thus confirming our previous observations (Wemke et al. ClinCancRes 2012). Prior to the initiation of the conditioning regimen positive eLPI levels were found in 26 of 109 evaluable patients. A significant correlation between LIC and pre-conditioning eLPI (Pearson's correlation coefficient: 0.470; p 〈 0.001) was noted. In fact, the median LIC in patients with a pre-conditioning eLPI 〉 0.4 was 190 µmol compared to 100 µmol/g in patients below this threshold (p 〈 0.001). Mean eLPI levels increased continuously during the course of the conditioning regimen and then gradually decreased starting on day +7, while most patients had negative eLPI levels by day +100 after allo-SCT (Figure 1). The presence of an eLPI above 0.4 prior to the initiation of the conditioning regimen was strongly associated with an increased early NRM (CI at day +100: 34.6 % vs. 6.0 % p 〈 0.001, Figure 2) and this association was confirmed in a multivariate analysis incorporating other factors known to predict for NRM (HR 7.0; 95% confidence interval: 2.076 to 23.91; p = 0.002). Of note, patients remaining LPI positive at day +14 also had a significantly increased NRM (19.0 % vs. 4.9 % p = 0.025), which also held true, when the analysis was restricted to patients being LPI negative prior to conditioning (12.5 % vs. 0.0 % p = 0.013). Patients having an eLPI above 0.4 prior to conditioning had a slightly higher CI of bacterial infections during the course of transplant (CI at day +100: 88.5 % vs. 83.3 %, p = 0.023). There was no association between a positive pre-conditioning eLPI and the occurrence of acute graft versus host disease of grade 2 or higher (CI: 39.1 % vs. 38.6 %). Conclusions The results of the prospective ALLIVE trial confirm recent single center observations that SIO prior to allo-SCT is associated with an increased mortality in AML and MDS patients. Given the fact that a positive eLPI prior to the initiation of the conditioning regimen and the persistence of positive eLPI levels after transplantation are strongly predictive for adverse outcome, it is reasonable to believe that reactive iron species are the key pathogenetic mediators in this context. Therefore, clinical trials assessing therapeutic interventions e.g. by peri-transplant iron chelation are warranted. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Wermke: Boehringer: Research Funding; Novartis: Research Funding. Bug:Celgene, Novartis: Research Funding; NordMedica, Boehringer Ingelheim, Gilead: Membership on an entity's Board of Directors or advisory committees; TEVA Oncology, Astellas: Other: Travel Grant. Theurl:Gilead Science: Research Funding. Platzbecker:Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Boehringer: Research Funding.

Description: Systemic mastocytosis with an associated hematologic neoplasm (SM-AHN) is the most common subtype of advanced SM (advSM), diagnosed in up to 80% of patients. The AHN is most frequently diagnosed as a myeloid neoplasm, e.g., SM-MDS/MPNu or SM-CMML. Acquired mutations in KIT (usually KIT D816, KIT D816mut) are detectable in 〉90% of patients. The basis for the SM-AHN phenotype is usually the multi-lineage involvement, e.g. monocytes, eosinophils and other non-mast cell lineages, of KIT mutations. Core binding factor (CBF) positive AML (CBFpos AML) represents a distinct subtype and is identified in 5-8% of all AMLs. KIT mutations, most frequently KITD816mut, are detectable in up to 45% of CBFpos AML patients and are associated with an adverse prognosis. There is, however, only little information on KIT D816mut/CBFneg AML. We therefore evaluated a) clinical and molecular characteristics, b) response to treatment and, c) survival and prognostic factors in 40 KIT D816mut/CBFneg patients with histologically proven SM and associated AML (SM-AML), collected at 4 centers of the European Competence Network on Mastocytosis (ECNM). Molecular analyses (n=32) revealed at least one additional somatic mutation (median, n=3) apart from KIT D816, most frequently SRSF2 (n=12, 38%), RUNX1 (n=11, 34%), TET2 (n=11, 34%), ASXL1 (n=10, 31%), or NPM1 (n=7, 22%). At least one mutation in SRSF2, ASXL1 or, RUNX1 (S/A/Rpos) was identified in 21/32 (66%) patients. At diagnosis of SM-AML 21/40 (52%) patients had an aberrant karyotype. Secondary AML evolved in 29/40 (73%) patients from SM ± associated myeloid neoplasm and longitudinal molecular analyses revealed acquisition of new somatic mutations (TP53, n=2; NPM1, n=1; RUNX1, n=1, ASXL1, n=1; BCOR, n=1; IDH1/2, n=1) and/or karyotype evolution in 15/16 (94%) patients at the time of SM-AML. Thirty-one of 40 (78%) patients were treated with intensive chemotherapy (ICT) with a complete response (CR) rate of 40%. Allogeneic stem cell transplantation (SCT) was performed in 12/40 (30%) patients with durable CR in 6/12 (50%) patients. S/A/Rpos and/or the presence of a poor-risk karyotype were adverse predictive markers for response to treatment. To further investigate whether KITD816mut/CBFneg AMLdefines a distinct AML subtype associated with SM, two independent AML databases (AMLdatabases) were retrospectively screened and 69 KIT D816mut/CBFneg AML patients identified. The comparison between KIT D816mut/CBFneg SM-AML from ECNM (n=40) centers with KIT D816mut/CBFneg AMLdatabases(n=69) revealed remarkable similarities: a) a high KIT D816 variant allele frequency (VAF) (median 34% vs. 29%), b) with the exception of SRSF2 (38 vs. 18%), a highly similar mutation landscape, rather comparable to that of advSM (Jawhar et al., Blood 2017) than to that of de novo AML, c) in contrast to de novo AML, a low frequency of FLT3 mutations (3 vs. 7%), and d) a high frequency of an aberrant karyotype (52 vs. 42%). The median overall survival (OS) of 40 KIT D816mut/CBFneg SM-AML and 17 evaluable KIT D816mut/CBFneg AMLdatabases was 5.4 (95% confidence interval, CI [1.7-9.1]) and 26.4 (95% CI [0-61.0]) (P=0.015) months, respectively (Figure 1). However, if only the patients with ICT ± allogeneic SCT were compared, median OS between the two groupswas not different (16.7 vs. 26.4 months, P=0.4). In multivariate analyses, S/A/Rpos and a poor-risk karyotype remained the only independent poor-risk factors with regard to OS. These results were independent of treatment modalities. We conclude that KIT D816mut/CBFneg AML is a new poor-risk subtype associated with SM (SM-AML). The remarkable clinical, genetic and prognostic similarities between SM-AML and AMLdatabases suggest that a significant proportion of the AMLdatabases patients may in fact have SM-AML. We therefore strongly recommend to determine serum tryptase and KIT D816 mutation status in all AML patients, and to perform bone marrow histology in KIT D816mut patients. These simple diagnostic measures would allow reclassification to SM-AML and inclusion of KIT inhibitors in established treatment modalities of AML. Disclosures Meggendorfer: MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Döhner:Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Amgen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria; Celator: Consultancy, Honoraria; Bristol Myers Squibb: Research Funding; Celator: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Astellas: Consultancy, Honoraria; Agios: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Agios: Consultancy, Honoraria; Bristol Myers Squibb: Research Funding; Jazz: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Pfizer: Research Funding; Pfizer: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding. Sperr:Novartis: Honoraria; Pfizer: Honoraria; Daiichi Sankyo: Honoraria. Valent:Incyte: Honoraria; Pfizer: Honoraria; Novartis: Honoraria. Reiter:Incyte: Consultancy, Honoraria.

Description: Introduction: A series of studies suggest that harnessing natural killer (NK) cell reactivity by killer cell immunoglobulin-like receptor (KIR) genotype based unrelated donor selection could further improve outcome after allogeneic hematopoietic cell transplantation (alloHCT). A Receptor-Ligand model has been proposed for donor selection which aims at augmenting NK cell activation while minimizing inhibition. Information on education of KIR2DS1-positive NK cells (Venstrom et al, NEJM 2012) and the predicted Receptor-Ligand interaction of KIR3DL1-positive NK cells is utilized for this algorithm. By combining this information donors can be classified as KIR-advantageous or disadvantageous. Patients with donors, characterized by activating KIR2DS1 and weak/non-inhibiting KIR3DL1, experienced less relapse and improved survival compared to patients with donors, characterized by lacking an activating KIR2DS1 but presence of strong-inhibiting KIR3DL1. This study aimed at validating this predictor in an independent cohort of patients. Methods: Donor samples were retrieved from the Collaborative Biobank (Dresden, Germany) and mapped to patient outcome data extracted from the German Registry for Stem Cell transplantation. KIR typing was performed using a high resolution amplicon-based next generation sequencing method. KIR typing at the allele level was based on sequencing of exons 3, 4, 5, 7, 8, and 9. The patient population was restricted to patients with AML or MDS. Donor and patient mapping was cross-checked by HLA-typing of the donor sample. The impact of the predictor on overall survival was tested in a Cox regression model adjusted for patient age, a modified disease risk index, performance status, donor age, HLA-match, sex match, CMV match, conditioning intensity, type of T-cell depletion and graft type. Results: Clinical data from 2314 patients were analyzed. The median age at alloHCT was 59.4 years (range, 18.1 to 79.6 years). The indication for alloHCT was AML for 80% of patients and MDS for 20% of patients. Disease risk was assessed as low, intermediate, high or very high in 1%, 52%, 42%, and 5%, respectively. Patient and donor were 10/10 matched in 78% of pairs, whereas a one locus mismatch was reported for 21% of pairs. Myeloablative, reduced-intensity and non-myeloablative conditioning regimens were used in 29%, 67%, and 4% of patients, respectively. ATG was administered in 77% and alemtuzumab in 3% of patients. Twenty percent of patients received no T-cell depletion. In total, 535 patients experienced relapse and 945 patients died. This number of events translated into a power of the confirmatory analysis for the predictor of KIR2DS1 and KIR3DL1 of 67%. Two-year overall and event-free survival for the whole cohort was 51% (95%-CI 48% to 53%) and 44% (95%-CI 42% to 47%) and the 2-year incidence of relapse and non-relapse mortality was 28% (95%-CI 26% to 30%) for both endpoints. In univariate analysis, overall survival (54% versus 56%) and the cumulative incidence of relapse of patients with a KIR-advantageous donor were comparable to patients with KIR-disadvantageous donors. The adjusted hazard ratio from the multivariable Cox regression model for the comparison of patients with KIR-advantageous versus KIR-disadvantageous donors was 0.99 (Wald-test, p=0.95) for overall survival and 1.12 (Wald-test, p=0.41) for relapse incidence. When evaluated separately, the two components of the predictor (degree of inhibition by KIR3DL1 & presence of activating KIR2DS1) did not have an impact on overall survival or the incidence of relapse (see Figure). Also, evaluation of the combined predictor in subsets of patients by disease, type of T-cell depletion and HLA-compatibility did not allow prediction of these outcomes. Conclusions: Relapse incidence and overall survival after unrelated donor alloHCT could not be predicted using information on activating KIR2DS1 and inhibiting KIR3DL1 donor genes in an independent cohort of predominantly Caucasian patients. The predictor had been developed in a cohort of patients with AML who were younger and predominantly had received myeloablative conditioning based on total-body irradiation, ATG was administered less often, but donors often were only partially HLA-compatible. The different outcome in the current analysis thus points at potential interactions between NK-cell mediated allo-reactivity and procedural variations of alloHCT. Figure Figure. Disclosures Schetelig: Sanofi: Consultancy, Research Funding; Janssen: Consultancy, Honoraria; Roche: Honoraria; Abbvie: Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding. Stelljes:Novartis: Honoraria; MSD: Consultancy; Pfizer: Consultancy, Honoraria, Research Funding; JAZZ: Honoraria; Amgen: Honoraria. Ayuk:Therakos (Mallinckrodt): Honoraria; Novartis: Honoraria; Celgene: Consultancy; Gilead: Consultancy. Bethge:Neovii GmbH: Honoraria, Research Funding; Miltenyi Biotec GmbH: Consultancy, Honoraria, Research Funding. Bug:Neovii: Other: Travel Grant; Novartis Pharma: Honoraria, Research Funding; Janssen: Other: Travel Grant; Celgene: Honoraria; Amgen: Honoraria; Astellas Pharma: Other: Travel Grant; Jazz Pharmaceuticals: Other: Travel Grant. Kobbe:Roche: Honoraria, Research Funding; Celgene: Honoraria, Other: Travel Support, Research Funding; Amgen: Honoraria, Research Funding. Beelen:Medac: Consultancy, Other: Travel Support. Fleischhauer:GENDX: Research Funding.

Description: Introduction Salvage high dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT) is used in fit patients with relapsed multiple myeloma (RMM) in clinical practice. However, the role of this approach in the era of continuous novel agent based treatment has not been defined in randomized trials. The ReLApsE trial compared lenalidomide/dexamethasone (Rd) re-induction, salvage HDCT/ASCT and lenalidomide (R) maintenance with standard continuous Rd in a randomized controlled multicenter trial. Methods Between 2010 and 2016, 282 patients were randomized of whom 277 constituted the intention-to-treat (ITT) population (arm B/A n=139/138). Arm B received 3 cycles of Rd (lenalidomide 25 mg, day 1-21; dexamethasone 40 mg, day 1, 8, 15, 22; 4 week cycles) re-induction, HDCT (melphalan 200 mg/m2), ASCT and R maintenance (10 mg daily) until progression (PD). Arm A was treated with Rd until PD. In both arms stem cells were harvested after the 3rd Rd cycle if no back-up transplant was available. Key inclusion criteria were 1-3 prior therapy lines, age ≤ 75 years, time to PD ≥ 12 months in case of front-line HDCT/ASCT and WHO PS ≤ 2. The primary endpoint was progression free survival (PFS). Secondary endpoints included overall survival (OS), response rates and toxicity. ISRCTN16345835, Eudra CT-No: 2009-013856-61. Results Arm B and A were balanced regarding age (median 61.3 vs. 62.2 years), ISS (I/II/III in 62.6/24.4/13% vs. 59.7/31/9.3%) and WHO PS (0/1/2 in 69.1/30.9/0% vs. 76.1/23.2/0.7%). Almost all patients had only 1 prior therapy line (arm B: 94.2% vs. arm A: 93.5%) and had received front-line HDCT/ASCT (92.8% vs. 94.2%). More patients in arm B had high risk cytogenetic aberrations (HR-CA; 42.9% vs. 31.6%) based on a higher frequency of t(4;14) (20.2% vs. 10.1%). The overall response rate (≥ partial response; ORR) for arm B and A was 77.9% and 74.6% (p=0.57) with 49.3% and 47.1% (p=0.81) achieving ≥ very good partial response as best response. Within a median follow up of 36.3 months, 183 PFS events and 76 deaths occurred. Median PFS in the ITT population was 20.7 months in arm B and 18.8 months in arm A without a statistically significant difference (HR 0.87; 95% CI 0.65-1.16; p=0.34). Median OS was not reached (NR) in arm B vs. 62.7 months in arm A (HR 0.81; 95% CI 0.52-1.28; p=0.37). In arm B, 41 patients (29.5%) did not receive the planned HDCT/ASCT. Thus, exploratory landmark (LM) analyses from HDCT and the contemporaneous Rd cycle 5 in arm A were performed (median interval from randomization to HDCT/Rd cycle 5: 117/122 days; n=103[B]/114[A]). They showed a trend towards superior PFS (23.3 vs. 20.1 months; HR 0.74; p=0.09) and significantly superior OS (NR vs. 57 months; HR 0.56; p=0.046) in arm B vs. A. Multivariate analyses revealed significant associations of treatment in arm B with superior LM PFS (HR 0.6; p=0.01) and LM OS (HR 0.39; p=0.006). Other factors in the LM multivariate models showing significant associations with survival were HR-CA (PFS, OS), number of prior therapy lines (PFS), and age (PFS). The ORR in arm B after HDCT/ASCT was significantly higher than in arm A after Rd cycle 5 (82.3% vs. 69.6%; p=0.04). Grade ≥3 adverse events were reported in 83% (arm B) and 74.5% (arm A; p=0.11). Grade ≥3 leukopenia/neutropenia was reported in 61.5 vs. 24.8% (p

Description: Background: Relapse of acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is frequently treated with 2nd allo-HSCT. Donor change has not yielded a significantly different outcome over choosing the original HLA-identical donor (Christopeit et al., JCO 2013). Using a haploidentical donor at second allo-HSCT might represent a feasible option (Tischer et al., BMT 2014) Study design and population: To define the role for second haploidentical allo-HSCT for AL relapsing after 1st allo-HSCT, a retrospective analysis was conducted 63 consecutive patients (female n=30, male n=33; AML n=51, ALL n=12) from 9 German centers were included. Median age was 40 years (range, 16-65). Grafts at 1st allo-HSCT were from matched related (32%), matched unrelated (33%), mismatch unrelated (18%), haploidentical donors (6%), and other donors, including cord blood (8%). Median duration of complete remission (CR) after 1st allo-HSCT was 414 days (range, 18-1633). Relapse was initially treated by cytoreductive chemotherapy in all cases; stage at start of conditioning for haploidentical second allo-HSCT was CR in 27%, active disease in 66% and not evaluated in 8%. Conditioning for second HSCT was myeloablative/reduced in 14%/86% To overcome the HLA barrier, 23 patients (36%) received ex vivo T-cell depletion (TCD), following either CD3/CD19 negative or CD34 positive selection. 4 patients received in vivo TCD only, two received no TCD at all, and 35 patients (55%) received high-dose cyclophosphamide post-transplant according to the Baltimore protocol. Results: Neutrophil engraftment was achieved after a median of 12 days (range, 8-26). 50 patients (78%) achieved CR after 2nd haploidentical allo-HSCT, out of which 23 (46%) relapsed again. After a median follow-up of 425 days, 47 patents had died, 22 from leukemia, and 25 from treatment-related causes. Kaplan-Meier estimated overall survival at one and two years from haploidentical second HSCT was 41+/-6% and 19+/-6%. Conclusions: Haploidentical second allo-HSCT is a promising approach to the treatment of AL relapse after first allogeneic transplant. OS rates at least comparable to alternative treatments were observed. Different strategies to overcome the HLA barrier seem feasible. This retrospective study was registered as NCT01997918 at clinicaltrials.gov. Maximilian Christopeit and Johanna Tischer as well as Wolfgang Bethge and Christoph Schmid contributed equally to this work. Disclosures No relevant conflicts of interest to declare.

Description: Background: During the last years, based on its efficacy and favourable toxicity profile the hypomethylating agent (HMA) Azacitidine (Aza) has proven to be a valuable treatment option for patients with AML or MDS who relapse after allo-SCT. In contrast to Aza, reports on the use of Decitabine (DAC), the second HMA approved in Europe for the treatment of AML, as salvage therapy for relapse after allo-SCT are scarce covering a total of 9 patients so far. This prompted us to perform a retrospective survey in order to gather more experience on the use of DAC after allo-SCT. Patients and Methods: Retrieving information from the EBMT Med-A form and a study-specific questionnaire we were able to analyze data of 36 patients (median age 56 years, range 21-72 years) from 6 German transplant centers who had received at least one cycle of DAC for the treatment of relapse of AML (n=29) or MDS (n=7) after allo-SCT. Median time to haematological (n=34) or molecular (n=2) relapse was 370 days (range 43-2623 days). Results: Overall, DAC was the first treatment for relapse in 16 pts (44%), whereas 20 pts (56%) had previously received one (n=14), two (n=2) or three (n=4) lines of salvage therapy for relapse after allo-SCT. This included 16 pts treated with Aza, 3 pts with intensive chemotherapy and 2 pts with radiation. Five pts had received a second allo-SCT and 9 pts donor lymphocyte infusions (DLI) before DAC therapy. Patients received a median of 2 DAC cycles (range, 1-10) with 24 pts (67%) treated with the approved dose of 20 mg/m2 for 5 days and 12 pts (33%) treated with 20 mg/m2 for 10 days based on the local policy of the individual transplant center. In addition to DAC, DLI (median number of DLI =1, range: 1-5) were administered to 22 pts (61%). Following treatment with DAC +/- DLI the median survival was 5 months (range 1 - 40 months). Six pts achieved a complete remission (CR, 17%) and 3 pts achieved a partial remission (PR, 8%) leading to an overall response rate of 25%. Median time to documentation of CR was 157 days (range: 47-255 days) and 4 DAC cycles (range: 1-8 cycles). Of 6 patients achieving CR after DAC, 3 had received DAC as first salvage therapy and 3 had previously received Aza, including 2 pts not responding to Aza and 1 patient switched to DAC therapy due to Aza intolerability. With a median follow-up of 12 months (range: 5-40 months), 3 of 6 patients remain in ongoing remission for 4, 23, and 33 months respectively without any further antileukemic therapy, while the other 3 patients died in remission due to infectious complications after second transplant. The 2-year overall survival rate of the entire group as calculated from the start of DAC therapy was 9%. Incidence and severity of acute GvHD (overall: 19%, grade I: 3%, grade II: 8%, grade III: 5%, grade IV: 0%, missing: 3%) and chronic GvHD (overall: 6%, limited 6%, extensive 0%) were low and mild. Conclusion: Our analysis shows, that also the second HMA DAC exerts relevant clinical efficacy in patients with AML or MDS relapsing after allo-SCT and can induce durable remissions in individual pts. Given the heterogeneity of our patient group and the limitations of a retrospective analysis this asks for confirmation in a prospective trial. Disclosures Platzbecker: Onconova, Teva, Celgene, Janssen, Novartis, Amgen: Honoraria, Research Funding. Kobbe:Jansen: Honoraria, Other: travel support; Celgene: Honoraria, Other: travel support, Research Funding.