ALBERT

Description: Abstract 1195 Poster Board I-217 The policy of the Rome Transplant Network (RTN), a metropolitan network of transplant Centers, for patients candidates to an allogeneic hematopoietic stem cell transplant (HSCT) and lacking an HLA identical sibling is the contemporary search for one the HSC alternative sources such as Matched Unrelated Donor (MUD),Cord Blood Unit (CBU) or Haploidentical Related Donor (HRD). The main aim of the RTN policy is the identification of a suitable donor in order to perform transplant in adequate timing. The selection criteria for MUD consist of a 8/8 HLA loci matching tested at low resolution for class I HLA and at high resolution (HR) for class II; one difference in C Ag is considered acceptable in case of both I and II class HR identity. CBU's selection criteria are instead based on cell doses (TNC≥2.5×107/kg and CD34+≥1× 105/kg) and on a HLA-compatibility ≥to 4/6 HLA Ag. From April 2006, the haplodentical option was also simultaneously considered, so all closer family members have been tested for the HLA. Here, we report the results of the intention to treat (ITT) analysis on the potential therapeutic impact of our transplant policy. Data were obtained from RTN database. From April 2006 to date, 196 pts have been candidated to receive an allogeneic HSCT for hematological disease. Sixty-six out of 196 (34%) underwent HSCT from HLA identical sibling, while a search process for an alternative donor was activated for 130 pts. Of 130 pts, 9 (7%) lost the eligibility to transplant early during the search process and 19 (15%) died of early disease progression in most cases: a suitable MUD or CBU had been identified for 13 of 19 within 3 months from the start of the search and only 6 pts (5%) died without an alternative donor had been found. To date, 73/102 evaluable pts (72%) lacking an HLA identical sibling have been transplanted (n=66: 23 MUD; 24 CBU; 19 HRD) or are willing to proceed towards the transplant (n=7: 3 MUD;2 CBU; 2 HRD). In summary, for all 196 candidates to an allogeneic transplant the eligibility was confirmed for 187 (95%), a suitable donor could be identified for 181 (92%) of all pts or 97% of the eligible ones and an allogeneic transplant could be performed for 168 (86%) of all candidates or 93% of those eligible. From this ITT analysis, we can conclude that, by adopting the RTN policy of widespread donor search and multiple transplant options, the allogeneic transplant can be offered as potential therapeutic procedure to a large majority of pts. Disclosures: No relevant conflicts of interest to declare.

Description: Background. During the last years, hematopoietic stem cell transplant from haploidentical donor is increasing by using the unmanipulated graft. We report the results of allogeneic bone marrow transplantation (BMT) from haploidentical donor primed with G-CSF in patients (pts) with high-risk acute myeloid leukemia (AML), who received an uniform TBF (Thiotepa, Busulfan, Fludarabine) conditioning regimen including antitymocyte globulin and an identical GVHD prophylaxis combining MTX+CSA, MMF and an anti-CD25 monoclonal antibody (Basiliximab). Patients and Methods. Since August 2005 to December 2014, 165 pts with high-risk hematological malignancy underwent unmanipulated BMT from fully haploidentical donor primed with 4µg/kg/day of G-CSF over 7 days. Of these 165 pts, 71 (median age 49 yrs, (range5-66) were affected by high-risk AML and were in early (CR1 and CR2: n=58) or advanced (〉CR2 or active disease: n=13) phase at time of transplant. All pts received the same myeloablative (MAC: n=47) or reduced intensity (RIC: n=24) TBF conditioning regimen including antithymocyte globuline for 4 days (days-4 through -1) and an identical graft-versus-host disease (GVHD) prophylaxis consisting of the classical association of MTX+CSA combined with MMF from day +7 to day +100 and the administration of 20 mg of Basiliximab at days 0 and +4. The donor were represented by: son (n=25); brother (n=18), mother (n=11), daughter (n=8), sister (n=6) and father (n=3). Anti-infective management, supportive care and transfusion policy were identical for all pts. The experience was conducted at 2 Institutions: Stem Cell Transplant Unit at University Tor Vergata of Rome (n=45) and at Civil Hospital of Pescara (n=26), Italy. Results. All pts engraftedwith full donor chimerism: median time 20 days (range, 11-35) and CI 94±3%. With a median follow-up (FU) of 3.9 yrs (range, 0.7-7.4), the 7-yrs probability of overall survival (OS) and disease free survival (DFS) for all pts was 45±6% and 43±6%, respectively. OS calculated by disease status at transplant was 53±7% at 7 yrs for 58 pts transplanted in early phase and 0.0% at 4 yrs for 13 transplanted in advanced phase (p=0.0027), DFS was 49±7% and 15±10% at 7 and 2 yrs (p=0.007), respectively. TBF-MAC Regimen: 47 pts (median age 43 yrs, range 5-63), in early (n=38) or advanced (n=9) phase at transplant received a TBF-MAC regimen. For all these pts the CI of engraftment was 94±4% at a median of 20 days (range, 12-35). The 100 day CI of acute GVHD (AGVHD) grade II-IV and III-IV was 32±7% and 6±4%, respectively. The CI of extensive chronic-GVHD (CGVHD) was 19±7%. In the patients transplanted in early phase the CI of transplant related mortality (TRM) at 6 months and 7 yrs was 21±7 and 27±7%, respectively. The CI of relapse at 1 and 7 yrs was 16±6% and 24±7%, respectively. With a median FU of 3.9 yrs (range, 1.3-7.4), the 7-yr probability of OS and DFS was respectively 60±8% and 52±8% with a plateau of the curve from 2 yrs after transplant. None of the 15 variables considered in multivariate analysis (Cox and Fine and Gray models) influenced significantly the outcomes. TBF-RIC Regimen: 24 pts (median age 61.5 yrs, range 41-66) were conditioned with TBF-RIC. All pts engrafted with full donor chimerism (CI 96±6%). The 100 day CI of AGVHD grade II-IV and III-IV was 33±10% and 13±7%, respectively. The CI of extensive CGVHD was 8±8%.Four pts were in advanced and 20 in early phase at transplant. For these last pts, the CI of TRM at 6 months and 6 yrs was 15±8% and 25±10%, respectively. The CI of relapse at 1 and 6 yrs was 15±8% and 27±11%, respectively. With a median FU of 4.1 yrs (range, 0.8-6), the 6-yr probability of OS and DFS was respectively 42±12% and 41±12% with a plateau of the curve from 2 yrs after transplant. In multivariate analysis, no significant factor was identified. Conclusions. Although the number of pts does not allow an extensive analysis of the results, the homogeneity of our series in terms of diagnosis, patient selection, conditioning regimen and GVHD prophylaxis supports the conclusion that haploidentical, G-CSF primed, unmanipulated BMT is a valid alternative for high-risk AML pts lacking an HLA identical sibling. The regimen of GVHD prophylaxis is highly effective and can be proposed in alternative to the use of post-transplant cyclophosphamide, proposed by the Baltimore group. Finally, TBF-RIC regimen can be confidently offered to unfit or older AML pts candidate to an haploidentical transplant. Disclosures No relevant conflicts of interest to declare.

Description: Abstract 3122 The outcome of high-risk acute myeloid leukemia (AML) patients not undergoing an allogeneic transplantation is extremely poor. Therefore transplantation from haploidentical donor represents an alternative option for these patients on urgency to be transplanted. We report the results of a study on unmanipulated, G-CSF primed, haploidentical bone marrow (BM) transplantation in patients with high-risk AML lacking a suitable HLA-identical donor. Materials and methods: Between August 2005 to December 2011 58 patients (median age: 44 yrs, range 5–71) with very high-risk AML (CR1=32; CR2=16; advanced stage=10) underwent BM transplant from haploidentical donor. As pretransplant regimens, 43 patients were conditioned with a myeloablative regimen (MAC), while 15 patients received a reduced intensity conditioning (RIC). Of the 58 patients, 43 received the chemotherapy based regimen consisting of Thiotepa, i.v. Busulphan and Fludarabine (TBF MAC or RIC protocol). All 42 patients received an identical GvHD prophylaxis consisting of pretransplant ATG combined with CSA, MTX, MMF and Basiliximab, an anti-CD25 monoclonal antibody. Donors were primed with G-CSF at 4 microgr/Kg/d for 7 consecutive days. BM was harvested on day 0 and infused unmanipulated. Results: The median number of total nucleated, CD34+ and CD3+ cells infused was 7.2 (1–28)x108/kg, 2.04 (0.8–11)x106/Kg and 2.9 (0.9–6.7)x107/Kg, respectively. Five patients died early. All 53 evaluable patients engrafted at a median of 21 (13–29) days and the cumulative incidence (CI) of neutrophil engraftment was 100% at 30 days. For 53 evaluable patients, acute GVHD was absent or just grade I in 25 (47%). The 100-day CI of II-IV and III-IV grade acute GVHD was 34+/−0.4% and 12+/−0.2% respectively. Extensive chronic GVHD occurred in 4 (8%) out of 49 evaluable patients and the 2-year CI of extensive chronic GVHD was 13+/−0.4%. The 1 and 5-year CI of transplant-related mortality (TRM) was 32+/−0.4% and 34+/−0.4% respectively. The overall CI of relapse was 20+/−0.4% at 1-year and 34+/−0.7% at 5-year. The overall and disease-free survival probability was 61+/−6% and 54+/−7% at 1 year, 49+/−7% and 42+/−7% at 5 years. For patients in early stage of disease (CR1+CR2: n=48) the 1 and 3-year probability of overall survival was 70+/−7% and 58+/−8%. Conclusions: Haploidentical transplant using G-CSF primed, unmanipulated BM is correlated with high engraftment rate, low incidence of acute and chronic GVHD, acceptable TRM and favorable outcome. This approach represents a valid and feasible alternative to transplant from matched unrelated donor or cord blood for high-risk AML patients particularly on urgency to be transplanted. Disclosures: No relevant conflicts of interest to declare.

Description: Background. Similar probabilities of survival have been reported for patients transplanted from Matched Unrelated Donor (MUD), Umbilical Cord Blood (UCB) or Haploidentical (Haplo) donors as alternative hematopoietic stem cell sources. However, few studies have compared these results with those obtained in patients transplanted from HLA Id-siblings (Id-sib). Moreover, all reported studies are retrospective and the criteria of donor selection were not predefined. We report the intention to treat (ITT) analysis results on 238 patients with high-risk acute myeloid leukemia (AML) prospectively transplanted according to the policy of the Rome Transplant Network (RTN), a metropolitan transplant program established in Rome in 2006. Patients and Methods. For AML patients eligible to an allogeneic transplant, the RTN policy consists of an algorithm of donor choice based on a hierarchy according to the following criteria: 1) HLA identical sibling; 2) MUD ≥8/10 HLA 3) UCB as single unit selected on the base of cell dose and number of HLA disparities (0-1/6 HLA: TNC ≥2.5x107/kg and CD34 ≥1x105/kg; 2/6 HLA: TNC ≥3.5x107/kg and CD34 ≥2x105/kg); 4) G-CSF primed, unmanipulated bone marrow Haplo donor. Myeloablative (MAC) or reduced intensity (RIC) TBF (Tiothepa, Busulfan, Fludarabine) conditioning regimen was identical for all patients, GVHD prophylaxis was uniform for each categories. of transplant Results. From January 2006 to December 2014, 238(89%) out of 303 adult patients candidates to an allogeneic transplant for high-risk AML were considered eligible. Overall, a donor was available for 205 (86%) of 238 eligible patients. At time of the analysis, 17 of these 205 patients (8%) had lost the transplant eligibility and 4 (2%) were still scheduled for transplant, therefore 184/205 (90%) patients with an available donor were finally transplanted from Id-sib (n=76), MUD (n=38), UCB (n=17) or Haplo (n=53) donors. The 8-yrs overall survival (OS) of the 238 eligible patients from time of HLA typing and of the 184 transplanted patients from time of the graft was 40±4%and 43±4%, respectively. By excluding the low number of UCB recipients (n=17), the OS was particularly dismal for the 34 patients transplanted in advanced disease phase (7±4% at 4 yrs), whereas for the 132 patients transplanted in early (CR1+ CR2) phase the 8-yr OS was 56±5%: 58±7% for 61 HLA Id-sib, 50±8% for 40 Haplo and 63±10% for 27 MUD recipients (P=NS). The OS of patients transplanted in early phase was 63±5% for 97 patients receiving MAC and 33±9% for RIC recipients. For these 97 patients, the survival by type of donor was 62±10% either for 47 Id-sib or 28 Haplo and 70±10% for 22 MUD recipients (P=NS). The results were analyzed by various donor/recipient (D/R) combinations such as age, sex and CMV status. The median donor age was 39 years (range, 18-70) and the median patient age was 43 years (range, 16-59): the 8-yr OS of patients (n=30) with younger D/R combination (D

Description: Abstract 2350 In this study we investigated the feasibility and clinical value of non T-cell depleted bone marrow transplantation (BMT) from HLA haploidentical related donor in patients with high risk hematological malignancies. Materials and Methods. Between August 2005 and May 2010, 71 patients were transplanted for acute myeloid leukemia (AML) (n=42), acute lymphoblastic leukemia (n=13), chronic myeloid leukemia (n=5), Hodgkin lymphoma (n=5), plasmacell leukemia (n=3), myelofibrosis (n=2) and myelodisplastic syndrome (n=1). Their median age was 35 years (5-71). At time of BMT, all patients were at very high risk: 39 were in early (complete remission 1 or 2) and 31 in more advanced stage of disease. Seventeen of them were given a previous transplant either autologous (n=14) or allogenic (n=3). All donors were HLA identical at 1 haplotype and mismatched for 2 (n=24) or 3 (n=47) loci on the unshared haplotype. As pretransplant regimen, 10 patients received a reduced intensity conditioning consisting of Fludarabine (Flu) alone (n=1), Flu + Thiotepa (Thio) + Melphalan (n=2) or Flu + Thio + i.v.Busulphan (Bu) (n=7), and 61 patients received a myeloablative therapy consisting of Aracytin + Cyclophosphamide combined with TBI (n=7) or Treosulphan (n=11) or Bu (n=11), whereas the last 32 consecutive patients underwent transplant after conditioning with the association of Thio + Flu + i.v. Bu. All patients received an identical graft-versus-host disease (GvHD) prophylaxis consisting of Fresenius Antithymocyte Globulin (5 mg/Kg/d from day -4 to -1) combined with Cyclosporine (1,5-3 mg/Kg/day i.v. from day -7 to +28 and orally 5 mg/Kg until day +365), Methotrexate (15 mg/sqm on day +1 and 10 mg/sqm on day +3, +6 and +11), Mycophenolate Mofetil (1 g/d from day +7 to +100) and the anti-CD 25 monoclonal antibody Basiliximab (20 mg i.v. on day 0 and +4). Bone marrow cells were harvested from all donors after priming with Filgrastim at 3–4 microg/Kg/d from day -7 to -1. Bone marrow cells were infused fresh and unmanipulated on day 0. Results. The median dose of total nucleated, CD34+ and CD3+ cells infused was 7.8 (1-28) ×108/kg, 2.1 (0.8-11) ×106/Kg and 28 (10-98) ×106/Kg, respectively. One patient had a primary graft failure and 5 patients died too early to be evaluated for engraftment. Results in terms of cumulative incidence (CI) of PMN engraftment, acute and chronic GvHD, relapse, transplant related mortality (TRM) and overall survival (OS) estimated with the Kaplan Meyer method are given in the Table. After a median follow-up of 16 (3-56) months, the 3 years probability of OS and disease-free survival (DFS) was 43% and 37% respectively for all patients (see Figure). The 3 years OS for the 42 patients with AML was 48% (61% for 30 patients transplanted in early stage and 18% for 12 patients transplanted in advanced stage, P=0.01). The 1 year OS for the 32 patients transplanted with the conditioning therapy employed in the last 2 years (Thio + Flu + i.v. Bu) was 72% in 18 patients transplanted in early stage and 52% in 14 patients transplanted in advanced stage (P=0.47). Conclusions. BMT from haploidentical donor using G-CSF primed, unmanipulated bone marrow cells and an intensive regimen for GVHD prophylaxis is correlated with high engraftment rate, low incidence of acute and chronic GVHD, acceptable TRM and favourable patient outcome. The results seem particularly encouraging for AML patients grafted at an early disease stage. In alternative to transplant from matched unrelated donor or cord blood, this approach can be offered to high risk patients with hematological malignancies particularly for those who are on urgency for a transplant. Results are given as % ± standard error Disclosures: No relevant conflicts of interest to declare.

Description: Despite advances in treatment and supportive therapies, outcome of acute myeloid leukemia (AML) remains dismal with approximately 40% of younger and less than 20% of elderly patients becoming long-term survivors. Stem cell transplantation (SCT) is a well-established post-remission therapeutic option, and in both its variants, autologous (AuSCT) and allogeneic (ASCT), it is often incorporated in modern treatment programs for it may reliably improve long-term prognosis. Ten years ago we demonstrated that the levels of minimal residual disease (MRD) before autologous stem cell transplant (AuSCT), assessed at the post-consolidation time point by multiparametric flow cytometry (MFC), affected outcome (1). Moreover, we have preliminarily observed that in MRD positive (MRDpos) patients, allogeneic stem cell transplant (ASCT) attenuates the negative prognostic impact of pre-transplant MRD positivity by conferring a significant survival advantage in terms of either overall (OS) or disease free survival (DFS) (2). At variance with this, others have shown that even in the setting of ASCT, pre-transplant MRD positivity is associated with a poor prognosis regardless of the graft-versus-leukemia (GVL) effect (3). The aim of the present analysis was to evaluate, in 81 MRDpos patients submitted to ASCT (45) or AuSCT (36), the impact on clinical outcome of different MRD levels. As previously reported, counting 3.5x10-4 (0.035%) residual leukemic cells (RLCs) or more in the bone marrow (BM) upon full hematological recovery after consolidation cycle, was regarded as a condition of MRD positivity. Patients with or above 3.5x10-4 RLC were arbitrarily divided into 3 different cohorts: 1) ≥0.035%≤0.1% (13 patients, 6 ASCT and 7 AuSCT); 2) 〉0.1%≤1% (52 patients, 31 ASCT and 21 AuSCT); 3) 〉1% (16 patients, 8 ASCT and 8 AuSCT). In the category no. 2, ASCT gave a significant 5-years OS (64,9% vs 17,9%, p

Description: Patients and Methods. At the Rome Transplant Network, a JACIE accredited metropolitan transplant program, a matched-pair analysis has been conducted on 116 of 255 patients transplanted between January 2008 and December 2012. The patients transplanted from Id Sib (n=58) or Haplo related donors (n=58) were completely matched for the following features: patient age, gender, diagnosis (7 subgroups), disease phase (early: CR1+CR2; advanced: 〉CR2+active disease), myeloablative or reduced intensity conditioning regimen consisting of Thiotepa, i.v. Busulphan and Fludarabine (TBF) association, donor age and donor/recipient sex, AB0 and CMV combinations. As GVHD prophylaxis, all patients received the standard CSA and MTX combination with the addition of ATG, MMF and Basiliximab in Haplo bone marrow recipients. The transfusion policy, supportive care and antinfectious prophylaxis were identical for all patients. Results. By comparingId Sib to Haplo recipients, the cumulative incidence (CI) of grade II-IV and III-IV acute-GVHD was 18±5% vs 42±7% (p=0.002) and 7±3% vs 14±5% (p=ns), respectively. The CI of extensive chronic GVHD was 23±6% for both patient series. The 5-year CI of TRM was 30±6% vs 36±6% (p=ns), respectively. The main causes of TRM were infections and the 6-month CI of Infection Related Mortality (IRM) was 26±6% in Haplo transplant and 10±4% in Id Sib (p=0.04). Although not statistically significant, the 5-year CI of relapse was higher in Id Sib (40±7%) than in Haplo recipients (28±6%). With a median follow-up of 3.5 years (range, 1 - 6), the 1- and 5-year disease free survival (DFS) was respectively 50±7% and 37±6% for Id Sibs and 45±7% and 36±6% for Haplo (Figure 1). Since 2 years after transplant, DFS curves of Id Sib and Haplo patients remained at plateau and were overlapping. Conclusions. This analysis considered a high number of factors for matching patients, who were grafted according to an identical transplant program. We can conclude that as consequence of a more intensive GVHD prophylaxis and therapy ensuing from higher incidence of 〉II grade acute GVHD, Haplo recipients are mainly exposed to a risk of early infection mortality. On the other hand, Id Sib patients seem to express less graft-versus-tumor activity with increasing risk of relapse after transplant. The identical long-term DFS justifies to consider the unmanipulated bone marrow transplant from haploidentical donor a valid alternative for patients lacking an HLA identical sib. Finally, it can appear at present provocative, but certainly realistic in perspective, the hypothesis that the donor choice in a familiar setting will mainly take into account other favourable donor/recipient combined characteristics rather than HLA compatibility. Figure 1 - Disease Free Survival Figure 1. - Disease Free Survival Disclosures No relevant conflicts of interest to declare.

Description: Multiparametric flow cytometry (MPFC) detection of minimal residual disease (MRD) represents a robust surrogate for the quality of complete remission (CR) and reliably predicts clinical outcome. In our experience, MRD detection provides prognostically relevant information when assessed at the post-consolidation time point. Ten years ago we demonstrated that the amount of MRD before autologous stem cell transplant (AuSCT) affected outcome. More recently, other authors have extended this observation to allogeneic stem cell transplant (ASCT) showing that pre-transplant MRD is a major determinant of prognosis regardless of graft-versus-leukemia (GVL) effect. The aim of our study was to evaluate, in an extended series of patients submitted to AuSCT or ASCT, the impact of a pre-transplantation MRD positive (MRDpos) or negative (MRDneg) status on overall survival (OS) and disease free survival (DFS). We analyzed 173 MRDpos and 53 MRDneg patients of whom 67 were submitted to AuSCT and 51 to ASCT. Eighty-two patients received no transplant because of age, poor performance status or insufficient stem cell harvest whereas 26, all in the MRDpos group, relapsed before transplant delivery. In the AuSCT group, before transplant, 32/67 (48%) were MRDneg and 35/67 (52%) MRDpos, with MRDneg group showing a superior OS (55% vs 20%, p=0.007). In the ASCT group, before transplant, 45/51 (88%) were MRDpos and 6/51 (12%) MRDneg. For 21 out of 51 (41%) sources of stem cells were matched unrelated donors (12) or haploidentical donors (9). In this subgroup, MRDpos and MRDneg patients shared a comparable 5-years OS (60% vs 56%, p=NS), with a 36% survival gain for those MRDpos who received ASCT as compared to AuSCT. Among MRDneg patients, no survival differences were demonstrated between those submitted to AuSCT or ASCT (55% vs 60%, p=NS). Such a lack of difference is likely due to the higher treatment related mortality (ASCT 3/6, 50% vs AuSCT 2/32, 6%, p=0.003) which counterbalanced the lower relapse rate in the ASCT group (ASCT 0/6, 0% vs AuSCT 11/32, 34%, p=NS). In conclusion, ASCT confers a significant survival advantage to MRDpos patients, attenuating the negative prognostic impact of pre-transplant MRD positivity. ASCT may expose MRDneg patients to an excess of toxicity suggesting that in these patients the allogeneic option should be postponed after a second remission. In MRDpos patients, AuSCT does not represent a valid therapeutic choice and ASCT, which should be timely delivered, also considering alternative sources of stem cells. Disclosures No relevant conflicts of interest to declare.

Description: Background Outcome of patients with high-risk acute myeloid leukemia (AML) not undergoing an allogeneic transplant after achieving complete remission (CR) is extremely poor. The risk of disease progression is high and the unavailability of an HLA identical sibling might jeopardizes their outcome, if the time to transplant from a matched unrelated donor (MUD) is expected to be longer than 3 months from CR. Being these patients on urgency to be transplanted, the search for an alternative donor should be preferably addressed towards the cord blood (CB) banks or an haploidentical family donor. Herein, we report the results on unmanipulated, G-CSF primed, haploidentical bone marrow (BM) transplantation in patients with high-risk AML in CR lacking a suitable HLA-identical donor. Patients and Methods from January 2008 to July 2013, 57 patients with a median age of 44 yrs (range, 5-66) (2 children aged 5 and 14 yrs) with very high-risk AML (CR1=32; CR2=14; advanced phase=11) underwent BM transplant from an haploidentical family donor (sibling=23; offspring=21; mother=10; father=3). All patients received a uniform myeloablative (MAC= 42 fit patients 55 yrs) conditioning regimen consisting of Thiotepa, i.v.Busulphan and Fludarabine (TBF) combination. All 57 patients received an identical GvHD prophylaxis consisting of pretransplant antithymocyte globulin (ATG) combined with cyclosporine, methotrexate, mycophenolate mofetil and basiliximab, an anti-CD25 monoclonal antibody. Donors were primed with G-CSF at 4 μg/Kg/d for 7 consecutive days. BM was harvested on day 0 and infused unmanipulated. Results the median number of CD34+ and CD3+ cells infused was 2 (0.6-11)x106/Kg and 3 (0.9-17)x107/Kg, respectively. Two patients died early. All 55 evaluable patients engrafted at a median of 20 days (range,12-29) and the cumulative incidence (CI) of neutrophil engraftment was 96.5±0.1% at 30 days. The 100-day CI of II-IV and III-IV grade acute GVHD was 33±0.4% and 11±0.2%, respectively. Extensive chronic GVHD occurred in 6 out of 51 (12%) evaluable patients and the 2-year CI of extensive chronic GVHD was 18±0.4%. The 6-mos and 1-year CI of transplant-related mortality (TRM) was 24±0.4% and 26±0.4%, respectively. The overall CI of relapse was 20±0.4% at 1-year and 38±0.8% at 5-year. With a median follow-up of 30 mos (range, 4-67), the 5-year probability of overall (OS) and disease-free survival (DFS) was respectively 52±7% and 43±7% for all patients, 65±9% and 58±9% for patients in CR1, 49±15% and 38±16% for patients in CR2, 12±11% and 0.0% (at 3yrs) for patients transplanted in advanced phase. For 33 patients transplanted in early (CR1+CR2) disease stage and conditioned with the TBF-MAC regimen, the 5-year probability of OS and DFS was 69±8% and 58±9%, respectively, while OS and DFS at 3 yrs were 45±15% for 11 patients in early phase receiving the TBF-RIC regimen. Conclusion Haploidentical transplant using G-CSF primed, unmanipulated BM is correlated with high engraftment rate, low incidence of acute and chronic GVHD, acceptable TRM and favorable outcome. This approach represents a valid and feasible alternative to MUD or CB transplant for high-risk AML patients in complete remission and on urgency to be transplanted. Disclosures: No relevant conflicts of interest to declare.

Description: We used flow cytometry to quantify minimal residual disease (MRD) in 56 patients with acute myeloid leukemia (AML) expressing a leukemia-associated phenotype. Thirty-four patients aged 18 to 60 years were entered into the AML-10 protocol (induction, consolidation, and autologous stem-cell transplantation [ASCT]), whereas 22 patients older than 60 years received the AML-13 protocol (induction, consolidation, and consolidation II). After induction, the level of MRD that was best associated with treatment outcome was 4.5 × 10−4 residual leukemic cells. However, the outcome in patients with at least 4.5 × 10−4 cells (n = 26) was not significantly different from that in patients with fewer leukemic cells (n = 30); there were 15 (58%) relapses in the first group and 12 (40%) relapses in the second. After consolidation, the most predictive MRD cutoff value was 3.5 × 10−4cells: 22 patients had an MRD level of 3.5 × 10−4 cells or higher and 17 (77%) of these patients had relapse, compared with 5 of 29 patients (17%) with lower MRD levels (P