Outcome Of Allogeneic Stem Cell Transplantation Research Articles

Efficacy and survival outcome of allogeneic stem-cell transplantation in multiple myeloma: meta-analysis in the recent 10 years.

Allogeneic hematopoietic cell transplantation (alloHCT) possessed direct cytotoxicity and graft-versus-multiple myeloma effect (GvMM). Growing trials have shown survival benefits of performing alloHCT in both newly diagnosed and relapsed MM. We aimed to provide a comprehensive analysis in the recent 10 years to verify the efficacy and survival outcome of alloHCT in MM patients. A total of 61 studies which provide data between 14/04/2013 and 14/04/2023 and a total of 15,294 data from MM patients who had undergone alloSCT were included in our study. The best response rates (CR, VGPR, PR) and survival outcomes (1-, 2-, 3-,5-, and 10-year OS, PFS, NRM) were assessed. We further conducted meta-analysis in the NDMM/frontline setting and RRMM/salvage setting independently. The pooled estimate CR, VGPR, and PR rates were 0.45, 0.21, and 0.24, respectively. The pooled estimates of 1-, 2-, 3-, 5-, and 10-year OS were 0.69, 0.57, 0.45, 0.45, and 0.36, respectively; the pooled estimates of 1-, 2-, 3-, 5-, and 10-year PFS were 0.47, 0.35, 0.24, 0.25, and 0.28, respectively; and the pooled estimates of 1-, 2-, 3-, 5-, and 10-year NRM were 0.16, 0.21, 0.16, 0.20, and 0.15, respectively. In the NDMM/upfront setting, the pooled estimate CR rate was 0.54, and those for 5-year OS, PFS, and NRM were 0.69, 0.40, and 0.11, respectively. In a relapsed setting, the pooled estimate CR rate was 0.31, and those for 5-year OS, PFS, and NRM were 0.24, 0.10, and 0.15, respectively. Our results showed constant OS, PFS, and NRM from the third year onwards till the 10th year, suggesting that alloSCT has sustained survival benefits. Good response rate and promising survival outcome were observed in the NDMM/ frontline setting. Although comparing with other treatments, alloSCT had a lower response rate and poorer short-term survival outcome, long-term follow-up could reveal survival benefits of alloSCT in MM patients.

Sequential Conditioning Does Not Improve Outcomes of Allogeneic Stemcell Transplantation in CMML Patients

Background: Allogeneic stem cell transplantation (SCT) is potentially curative therapy for patients with CMML. Data on optimal allo-SCT conditioning in CMML Patients is scarce. Methods: This retrospective study from the Department of Stem Cell Transplantation at the University Medical Center Hamburg, Germany, compared allo-SCT outcomes in CMML patients across three conditioning regimes: Thiotepa-Busulfan (TB), Sequential FLAMSA-Busulfan Fludarabine (FLAMSA-FB), and Treosulfan-Fludarabine (Treo-Flu). TB consisted of Thiotapa ( 5mg/Kg; a total dose of 10mg/Kg) on day -6 and -5 and Busulfan (3.2mg/Kg; total dose 6.4mg/Kg or 9.6mg/Kg) on days -4 and -3 or -4 to -2. FLAMSA-FB regimen consists of fludarabine (30 mg/m 2 ; total dose 120 mg/m 2 ), amsacrine (100 mg/m 2 ; total dose 400 mg/m 2 ), and cytarabine (1 g/m 2 ; total dose 4 g/m 2 ) therapy from days -11 to minus -8, followed by a three-day interval without therapy and Busulfan from day -4 to -2 with a total dose of 6.4mg/Kg and Fludarabine on day -4 and -3 (30 mg/m 2, total dose 60mg/m 2 ).Treo-Flu regimen consisted of Treosulfan (12 g/m 2 , total dose 36 mg/m 2 ) on days-6 to -4 and fludarabine (30 mg/m 2 ; total dose 150 mg/m 2 ) on days -6 to -2. Results Sixty-nine consecutive patients with CMML who underwent allo-SCT between the years 2006-2022. Twenty-two received TB, 27 received FLAMSA-FB, and 20 received Treo-Flu conditioning. Transplant sources included matched related donors (MRD, 8 patients), mismatched related donors (MMRD, 8 from TB), matched unrelated donors (MUD, 31), and mismatched unrelated donors (MMUD, 23) with significant group variations (p<0.001). Most Patients received ATLG for GVHD prophylaxis (TB 68%, FLAMSA-FB 93%, Treo-Flu 85%, p=0.08). Regarding CPSS-mol scores, the TB group exhibited a significantly higher proportion of high (46%) and intermediate-2 scores (32%) than FLAMSA-FB (11% high, 7% intermediate-2) and Treo-Flu (40% high, 20% intermediate-2) (p=0.001). One TB patient experienced primary graft failure, but engraftment times were comparable across groups. Although not statistically significant (p=0.07), the TB group showed a trend towards improved 3-year OS rates (84%) compared to FLAMSA-FB (37%) and Treo-Flu (49%). The TB group also displayed significantly higher 3-year PFS rates (79%) compared to FLAMSA-FB and Treo-Flu (both 30%), (p=0.03). (Figure 1) No significant differences were observed in 3-year non-relapse mortality (NRM) across the TB (17%), FLAMSA-FB (30%), and Treo-Flu (26%) groups (p=0.7). Interestingly, no TB patients relapsed at 3 years, contrasting with the FLAMSA-FB (41%) and Treo-Flu groups (43%, p=0.02). Lastly, cumulative incidences of acute GVHD grade II-IV (TB 41%, FLAMSA-FB 35%, Treo-Flu 30%, p=0.75) and all-grade chronic GVHD (TB 50%, FLAMSA-FB 65%, Treo-Flu 40%, p=0.35) were similar across groups. Conclusion Our study suggests that sequential conditioning with FLAMSA-FB does not improve Transplant outcomes in patients undergoing allo-SCT for CMML.

Post Allogeneic Stem Cell Transplant Outcomes Following Response to Hypomethylating Agent Therapy in Myelodysplastic Syndromes Are Predicted By Persistent International Prognostic Scoring System-Molecular Risk

Introduction: The International Prognostic Scoring System-Molecular (IPSS-M) ( Bernard NEJM Evidence 2022) and the 2023 International Working Group (IWG) response criteria for myelodysplastic syndrome (MDS) ( Zeidan Blood 2023) are used to more accurately assess prognosis and therapeutic response in MDS. However, it is unknown if these tools can be used to predict outcomes post-allogeneic hematopoietic stem cell transplant (HCT). We sought to understand the impact of pre-HCT IPSS-M on post-HCT outcomes in patients (pts) with MDS who responded to hypomethylating agent (HMA) therapy. Methods: Pts with MDS treated with HMA (azacitidine or decitabine) who received an HCT post-HMA at Dana-Farber Cancer Institute from January 2014 to December 2020 were included. Response to HMA was assessed by 2023 IWG response criteria and was defined as complete remission (CR) + CR with bi-lineage blood count recovery (CRbi) + CR with uni-lineage blood count recovery (Cruni) + CR with partial hematological recovery (CRh). Combined clinical and molecular risk was assessed by IPSS-M at times of diagnosis and of HCT, the latter using the bone marrow biopsy and sequencing data collected closest to HCT. High risk was defined as IPSS-M moderately high, high, and very high, whereas low risk was defined as IPSS-M very low, low, and moderately low. Results: A total of 148 pts with MDS who received HMA and underwent subsequent HCT were included. Median age was 64 years (range 26-79) and 61.5% were men. Pts were diagnosed with MDS-EB1 (26.4%), MDS-EB2 (45.3%), and other MDS subtypes (28.3%). IPSS-M at time of diagnosis was very low (2%), low (10.1%), moderate low (6.1%), moderate high (8.8%), high (31.8%), and very high (22.3%). IPSS-M pre-HCT was very low (12.8%), low (8.8%), moderate low (10.8%), moderate high (12.8%), high (20.3%), and very high (10.8%). IPSS-M at diagnosis and pre-HCT could not be calculated because of missing molecular data in 18.9% and 23.6% of pts, respectively. Pts received a median of 4 HMA cycles (range 1-20) and were treated with azacitidine for 7 days (54.1%), decitabine for 5 days (39.2%), and other schedules (6.7%). Prior to HCT, IWG 2023 responses were: CR (15.5%), CRbi (14.9%), CRuni (19.6%), CRh (0.7%), partial remission (PR: 1.4%), hematological improvement (HI: 9.5%), and no response (38.5%). Most pts received HCT from either a matched unrelated (60.8%) or matched related donor (18.2%) with reduced intensity conditioning (74.3%). Pts received graft versus host disease prophylaxis with tacrolimus (tac)/methotrexate (MTX) (54.7%), tac/MTX/sirolimus (19.6%), post-transplant cyclophosphamide/mycophenolate mofetil/tac (15.5%), tac/sirolimus (8.1%), other (2%). Median HCT-comorbidity index (CI) was 2 (range 0-13) and 48.6% pts had HCT-CI ≥ 3. For the entire cohort, the median follow-up time among ongoing survivors was 48.3 months (range 5.5-101.3). Among pts who responded to HMA per IWG 2023 criteria (CR/CRbi/CRuni/CRh), those who had high risk by IPSS-M prior to HCT had significantly shorter median overall survival (OS) (27 months; 95% CI 7.5-51) compared to pts with a low risk by IPSS-M (not reached; p=0.016) ( Figure A). Cumulative incidence of relapse (CIR) at 4 years was 66% for pts with high risk and 31% for low risk (p=0.034) ( Figure B). Pts with response to HMA with high risk by IPSS-M had lower OS (4-year OS: 27% versus 53%; p=0.016) and progression-free survival (4-year PFS: 19% versus 50%; p=0.018) but similar non-relapse mortality (NRM) (4-year NRM: 16% vs. 19%; p=0.66) post-HCT compared to pts with low risk at time of HCT. Conclusion: For pts with MDS who achieve a response to HMA prior to HCT, combined clinical/molecular risk, as assessed by IPSS-M, has an important prognostic impact on post-HCT outcomes. Pre-HCT risk should be evaluated for prognostication and to guide patient care, including future prospective studies evaluating novel agents for post-HCT therapy.

Low levels of CD26 on certain cellular subtypes of donor harvest is associated with better clinical outcomes post allogeneic stem cell transplantation through regulation of NF-κB pathway and pro-inflammatory cytokines

BackgroundWe had previously reported significant association of immunoectoenzyme CD26 expression on donor harvest with acute Graft-versus-Host-Disease (aGVHD) in allogeneic stem cell transplantation (ASCT) patients. The current study was aimed at analysing CD26 signaling pathway molecules and understanding their impact on immune reconstitution and clinical outcomes post-ASCT. Subjects and MethodologyThe study cohort included 26 transplant donors/patients who underwent reduced intensity (n = 21), myeloablative (n = 4) and non-myeloablative (n = 1) ASCT for hematological malignancies. Donors were matched related donors (n = 19) and haploidentical donors (n = 7). Surface expression of CD26, CD73 and ADA, and various immune cell subtypes were assessed by multicolour-flow cytometry. Soluble CD26 (sCD26) and cytokine levels were measured in plasma samples by ELISA and Multiplex Luminex assay, respectively. Immune cells from healthy individuals were stimulated with phytohemagglutinin (PHA) in the presence or absence of CD26 inhibitor. Effect of CD26 inhibition on NF-κB localization in PHA stimulated cells was analysed by immunofluorescence and confocal microscopy. Pro-inflammatory cytokines from the culture supernatants were detected with Cytometric bead array flow cytometry. Association of all measured markers with clinical outcomes was evaluated using appropriate statistical tests. ResultsCD26 surface expression on PBSC donor harvest cells showed increased risk of chronic GVHD (cGVHD, p = 0.055). Amongst the various immune cell subtypes, decreased B cells in harvest showed significant association with aGVHD (p = 0.022) whereas increased myeloid dendritic cells and CD3+T cells at Day100 in peripheral blood of transplant recipients correlated with cGVHD (p = 0.046) and aGVHD (p = 0.035), respectively. Further, high sCD26 in transplant recipients at Day100 exhibited association with reduced event-free survival (EFS) (p = 0.011). Higher CD26 expression on more & less mature NK cells, naïve & post-switched memory B cells and Treg cells in the donor harvest (p < 0.05) led to lower EFS in transplant recipients. Mechanistically, CD26 inhibitor caused dose-dependent reduction in CD26 enzyme activity and in pro-inflammatory cytokine production in post mitogen-stimulated T cell cultures. ConclusionOur study has implicated that lower CD26 expression on immune cell subtypes of the donor stem cell harvest is associated with reduced risk of GVHD and better survival. The underlying mechanism was found to be through NF-κB pathway and pro-inflammatory cytokines. Based on these observations, chemically designed or natural resources-based CD26 inhibitors can be explored further in clinical trials for improving ASCT outcomes.

Allogeneic stem cell transplant outcomes between TBI-containing reduced intensity and myeloablative conditioning regimens for ALL in complete remission

Total-body irradiation (TBI)-based conditioning regimen is preferred in acute lymphoblastic leukemia (ALL). We retrospectively evaluated allogeneic stem cell transplant (alloSCT) outcomes of 86 adult ALL patients in complete remission (CR) who received TBI-containing reduced intensity (RIC) (Flu/Mel/TBI = 31) and myeloablative conditioning (MAC) (VP16/TBI = 47; CY/TBI = 8) between January 2005 and December 2019. All patients received peripheral blood allografts. Patients in the RIC group were older than the MAC group (61 years old versus 36 years, p < .001). Donor was 8/8 HLA-matched in 83% and unrelated in 65% of patients. Three-year survival was 56.04% for RIC and 69.9% for MAC (HR 0.64; p = .19). Propensity score-based multivariable Cox analyses (PSCA) did not demonstrate any difference in grade III–IV acute graft versus host disease (GVHD) (SHR 1.23, p = .91), chronic GVHD (SHR 0.92, p = .88), survival (HR 0.94, p = .92), and relapse-free survival (HR 0.66, p = .47) between both groups, while relapse rate was lower (SHR 0.21, p = .02) for MAC compared to RIC. Our study did not demonstrate any difference in survival for TBI-containing RIC and MAC alloSCT for adult ALL in CR.

Cryopreserved versus fresh peripheral blood allogeneic stem cell transplantation outcomes in patients receiving post-transplant cyclophosphamide for graft-versus-host prophylaxis during the COVID-19 pandemic: a single center experience.

Cryopreservation of grafts is not common practice in allogeneic hematopoietic stem cell transplant (HSCT) recipients. However, our center had to use cryopreserved cells for allogeneic HSCT during the COVID-19 pandemic to avoid delays in transplantation due to uncertainty regarding patient and donor exposures. We retrospectively evaluated post-transplant engraftment and survival outcomes of adult patients who received cryopreserved versus fresh allografts during the COVID-19 pandemic. Fifty-five patients with hematologic malignancies received either cryopreserved (n = 34) or fresh (n = 21) allogeneic HSCT using peripheral blood stem cells between January 2020 and December 2020. At a median follow-up time of 15months, cryopreserved allograft recipients had significantly lower overall survival (OS) (p = 0.02). They also experienced significantly delayed neutrophil (p = 0.01) and platelet engraftments (p < 0.0001), as well as higher red blood cell transfusion-dependence after day + 60 (67.6% vs. 28.6%; p = 0.01). Significantly more cryopreserved allograft recipients received donor lymphocyte infusion than fresh allograft recipients (35.3% vs. 4.8%, p = 0.01). Neither relapse-free survival nor non-relapse mortality differed significantly between the two groups. Cryopreservation of allografts in combination with post-transplant cyclophosphamide may negatively affect engraftment and OS outcomes in HSCT recipients.

PB2140: ALLOGENEIC STEM CELL TRANSPLANTATION IN RARE T-NHL SUBTYPES: FOCUS ON AITL, MF/SS, HSTCL. A SINGLE BMT-UNIT EXPERIENCE.

Background: Angioimmunobastic Lymphoma (AITL) and T-γδ-hepatosplenic lymphomab(HSTCL) consist two rare, aggressive T-NHL subtypes while patients with Mycosis Fungoides/Sézary (MF/SS) syndrome may have a more indolent disease course but are rarely cured with conventional therapy. AutoHSCT may offer prolonged survival in selected cases of AITL but relapses are common. Despite the significant innovation in therapeutics of hematological malignancies, little progress is made in these lymphomas management. Due to the rarety as well as to the fact that at least for AITL and MF/SS median age at diagnosis is greater than 60 years old, there is limited number of reports on allogeneic stem cell transplant outcomes and data from prospective studies are missing Aims: To describe our experience on allogeneic transplant outcomes in a small cohort of relatively young patients with AITL (3), HSTCL (3), MF/SS (8) Methods: Records of 14 patients (6 men, 8 women), who underwent consecutively allogeneic stem cell transplant from 01/01/2008 to 31/12/2019, were retrospectively studied. Survival status was censored on 15th February 2022. All had consented to the use of their data before conditioning initiation Results: Median age was 51.5, 34 and 49 years old in MF/SS, HSTCL and AITL respectively. All donor types had been used. All MF/SS had been submitted to RIC alloHSCT with FLU MEL +/-ATG and no MF/SS patient was on CR at the time of alloHCT (3 PR, 2SD, 3PD). 1 patient with AITL was in CR at the time of alloHSCT and remains alive, relapse and GVHD free 28 months after alloHSCT while 1 patient in PR at the time of alloHSCT is alive in CR, relapse/GVHD free 6 years later. 1 patient with HSTCL is alive relapse/GVHD free 12 years after HSCT. There were no early deaths before day 30 in the whole cohort, while 3 patients died before day 100 – 1 with AITL due to primary graft failure, 2 with MF/SS due to refractory disease. 2 patients with HSTCL died due to early disease relapse, 4 and 6 months post-transplant respectively, while 2 patient with MF/SS died 7 and 15 months post-transplant due to EBV positive PTLD and severe gastrointestinal PTLD complicated by CMV-colitis. At the date of data censoring 4 patients with MF/SS were alive in CR and relapse/GVHD free, while 1 patient was alive but in PR after the second relapse treated with pembrolizumab 39 months after alloHSCT Summary/Conclusion: Due to the rarity of the studied lymphoma subtypes our cohort was small and proper statistical analysis of data could not be done safely. However, it becomes clear that younger patients with MF/SS -even with relapsed/refractory disease - may benefit of prolonged survival with allogeneic stem cell transplant. For patients with HSCTL, allogeneic stem cell transplant is considered “sine qua non” for survival and cure, while fit patients with AITL should be considered candidates for alloHSCT. Immunological manipulation may contribute to relapse management.

167 - Measurable Residual Disease Outcompetes Cytogenetics in Predicting Leukemia Free Survival Following Allogeneic Stem Cell Transplantation Outcomes in Adults with Acute Lymphoblastic Leukemia

167 - Measurable Residual Disease Outcompetes Cytogenetics in Predicting Leukemia Free Survival Following Allogeneic Stem Cell Transplantation Outcomes in Adults with Acute Lymphoblastic Leukemia

155 - Allogeneic Stem Cell Transplant Outcomes in Patients with DDX41 Mutated Myeloid Malignancies

155 - Allogeneic Stem Cell Transplant Outcomes in Patients with DDX41 Mutated Myeloid Malignancies

The impact of transportation time on apoptosis in allogeneic stem cell grafts and the clinical outcome in malignant patients with unrelated donors

BackgroundThe quality of cells in peripheral blood stem cell (PBSC) grafts is important for allogeneic stem cell transplantation outcome. The viability of PBSC grafts may decrease during transportation time between donor and transplant center. We hypothesize that the graft viability based on apoptosis and necrosis in the graft may better reflect graft quality and clinical outcome. MethodsPBSC graft viability from unrelated donors was analyzed in 91 patients. Viable cells were defined as 7-aminoactinomycin D– and Annexin V–negative. The clinical outcome, including survival, transplant-related mortality and graft-versus-host disease (GvHD), was correlated to graft viability. ResultsGrafts transported for 1 day had a median viability of 86.4% (range 63.8 to 98.9%), and grafts transported for 2 days had median viability of 83.2% (range 52.8% to 96.2%) (P = .003). Grafts were divided into two groups based on the median graft viability of 85.1%. Patients who received low viability grafts had lower 1-year survival of 63.7% compared with 88.9% for those who received high viability grafts (P = .007). In the multivariate analysis, transplant-related mortality (TRM) was higher in the low viability group (P = .03), whereas overall survival was not significantly associated with graft viability. The incidence of acute GvHD grade II to IV, chronic GvHD and relapse risk remained comparable between the groups. ConclusionLow graft viability was an independent predictor of 1-year survival and TRM after adjusting for multiple confounders. Better graft quality markers are important for the detection of clinically important variations in the stem cell graft.

Impact of Age on Hospitalization and Readmission on Post Allogeneic Stem Cell Transplantation Outcome, Single Center Experience

Background: Recent advances and improvement of supportive care allowed allogeneic stem cell transplantation (HCT) to be offered to selected older patients. However, data regarding outcome and factors affecting the outcomes are limited.Method: We retrospective analyzed the outcome in 332 patients, median age 65 years (60-76), who underwent HLA-matched related (n=85), matched unrelated (n=205) and haploidentical donor (n=42) HCT, between January 2014 to December 2019. Of these 60% were male. Diagnosis was leukemia: 193, MDS: 76, MF: 46 and others: 17. Graft source was PBSC in 98%. Reduce-intensity conditioning regimen was used in 95%, and in vivo T-cell depleted in 89% of patients. We categorized them to 3 age-groups (G): G1 60-65y, (n=175), G2 >65-70y (n=127), and G3 >70y (n=30).Cox models were used to compare the rates of overall survival (OS), non-relapse mortality( NRM), event free-survival (EFS), length of hospitalization for HCT, GVHD and reasons of re-hospitalization during the first year post HCT.Results: The median follow up was 14 months (range: 1-123 months). Median days of hospitalization during HCT period were 30-days (range: 20-132 days), with trend towards significance when stratified by age group (p=0.049). HCT-CI scores were 0-1 (n=143), 2-3 (n=107) and >3 (n=70). The cumulative incidences of grade II-IV acute-GVHD was 38.3% and 16.3% for grades III-IV. Moderate-severe chronic-GVHD was 23.7%. Increasing age was not associated with increases in acute GVHD (p=0.86) or chronic-GVHD (p= 0.6). Overall, 188 (56%) patients were re-hospitalized within the first 6-month of HCT, and 61 (18%) in the second 6-month period. The 2-year OS rate (Fig 1) were 56% in G1, 53% in G2 and 34% in G3 (p=0.05). The 2-year EFS rate (Fig 2) were 54% for G1, 49% for G2, and 31% for G3 (P=0.04). Cumulative incidence of NRM at 2-year (Fig 3) were 25% in G1, 36% in G2 and 52% in G3 (p=0.008). Further results are illustrated in Table 1. Risk factors such as age, KPS, HCT-CI, donor-type, readmission and GVHD were analyzed for their associations with outcomes using univariate analyses, those with significant results entered in multivariate-analysis Table 2. Patients aged 60-≤65 had significantly better EFS (p=0.04) and associated with a border line significant trend for lower NRM (p=0.05) than those aged >70. Re-admission in the first 6-month post HCT had a significant impact on the OS, EFS and NRM. HCT-CI >3 had significant impact on NRM.Conclusion: Age had a significant impact on hospitalization period during HCT. Age >70 had significant impact on EFS and trend toward higher NRM. HCT-CI, acute and chronic-GVHD and readmission in first 6-month post-HCT were significant risk factors. Readmission in the first 6 months correlated with lower OS, EFS and higher NRM. Acute GVHD III-IV or moderate-severe chronic GVHD associated with poor outcomes. Selecting patients based on HCT-CI, and good management of GVHD and post-HCT complication may improve the clinical outcome. [Display omitted] DisclosuresLaw: Novartis: Consultancy; Actinium Pharmaceuticals: Research Funding. Kim: Bristol-Meier Squibb: Research Funding; Pfizer: Honoraria; Paladin: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Lipton: Bristol Myers Squibb, Ariad, Pfizer, Novartis: Consultancy, Research Funding.

Prognostic Factors for Progression in Patients (pts) with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ALL) in Complete Molecular Response (CMR) within 3 Months of Therapy with Tyrosine Kinase Inhibitors (TKIs)

Prognostic Factors for Progression in Patients (pts) with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ALL) in Complete Molecular Response (CMR) within 3 Months of Therapy with Tyrosine Kinase Inhibitors (TKIs)

Abstract 2762: The comparison of allogeneic stem cell transplantation outcomes between haploidentical donor and international donor: A retrospective multi-institutional study in Korea

Abstract Introduction: The successful rate of hematopoietic stem cell transplantation (HSCT) from HLA-mismatched donor has been increased according to the development in management of complications including graft versus host disease (GVHD) and infections. Especially, haploidentical HSCT provides an opportunity for all patients who do not have HLA-matched sibling donor. Methods: In this study, we compared HSCT outcomes between haploidentical familiar donor and international donor (donors from Japan, China, Germany, Unites States of America and Taiwan) in acute leukemia patients. We reviewed the overall survival (OS), relapse free survival (RFS) and complications. Results: Total 142 acute leukemia patients performed HSCT from 2000 to 2016; 98 patients underwent haploidentical donor transplantation and 44 patients underwent international donor transplantation. Major variables such as age, sex, disease status and the number of CD34 stem cells were not statistically different between two groups. In survival analysis, there was no significant difference according to the donor-type. 1-year OS rate for haploidentical transplantation group was 44.1% and 52.3% for international transplantation group (p=0.345). 1-year RFS rate was 36.6% versus 40.9%, respectively (p=0.362). In addition, the incidence of complication events was similar between two groups. The acute GVHD in haploidentical group and international group were 42.9% and 43.2% (P=0.97), and the infection event within 30days after transplantation were 49.5% in haploidentical group and 34.1% in international group (p=0.09). The cumulative incidence of chronic GVHD was no significantly different (P=0.34), respectively. Conclusion: These data suggest that HSCT from haploidentital donor shows similar outcomes including survival outcomes and complications with international donor transplantation. Therefore, haploidentitial donor transplantation can be good choice for acute leukemia patients who have no HLA_matched sibling donor. Citation Format: Hyunkyung Park, Yoo Jin Lee, Sang-Jin Shin, Jayoun Lee, Inho Kim, Sung-Soo Yoon, Silvia Park, Hyewon Lee, Joonho Moon, Jun Ho Jang, Youngil Koh. The comparison of allogeneic stem cell transplantation outcomes between haploidentical donor and international donor: A retrospective multi-institutional study in Korea [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2762. doi:10.1158/1538-7445.AM2017-2762

Characteristics predicting outcomes of allogeneic stem-cell transplantation in relapsed acute myelogenous leukemia.

Allogeneic hematopoietic stem-cell transplantation (ahsct) is associated with significant morbidity and mortality, but it can cure carefully selected patients with acute myeloid leukemia (aml) in second remission (cr2). In a cohort of patients with aml who underwent ahsct in cr2, we determined the pre-transplant factors that predicted for overall survival (os), relapse, and non-relapse mortality. We also sought to validate the prognostic risk groups derived by Michelis and colleagues in this independent population. In a retrospective chart review, we obtained data for 55 consecutive patients who underwent ahsct for aml in cr2. Hazard ratios were used to describe the independent effects of pre-transplant variables on outcome, and Kaplan-Meier curves were used to assess outcomes in the three prognostic groups identified by Michelis and colleagues. At 1, 3, and 5 years post-transplant, os was 60%, 45.5%, and 37.5% respectively. Statistically significant differences in os, relapse mortality, and non-relapse mortality were not identified between the prognostic risk groups identified by Michelis and colleagues. Women were less likely than men to relapse, and a modified European Society for Blood and Marrow Transplantation (mebmt) score of 3 or less was associated with a lower non-relapse mortality. The 37.5% 5-year os in this cohort suggests that, compared with other options, ahsct offers patients with aml in cr2 a better chance of cure. Our study supports the use of the mebmt score to predict non-relapse mortality in this population.

Harnessing bone marrow resident regulatory T cells to improve allogeneic stem cell transplant outcomes.

Regulatory T cells (Treg) are a suppressive T cell population which play a crucial role in the establishment of tolerance after stem cell transplantation (SCT) by controlling the effector T cell responses that drive acute and chronic GVHD. The BM compartment is enriched in a highly suppressive, activated/memory autophagy-dependent Treg population, which contributes to the HSC engraftment and the control of GVHD. G-CSF administration releases Treg from the BM through disruption of the CXCR4/SDF-1 axis and further improves Treg survival following SCT through the induction of autophagy. However, AMD3100 is more efficacious in mobilizing these Treg highlighting the potential for optimized mobilization regimes to produce more tolerogenic grafts. Notably, the disruption of adhesive interaction between integrins and their ligands contributes to HSC mobilization and may be relevant for BM Treg. Importantly, the Tregs in the BM niche contribute to maintenance of the HSC niche and appear required for optimal control of GVHD post-transplant. Although poorly studied, the BM Treg appear phenotypically and functionally unique to Treg in the periphery. Understanding the requirements for maintaining the enrichment, function and survival of BM Treg needs to be further investigated to improve therapeutic strategies and promote tolerance after SCT.

Rifaximin preserves intestinal microbiota balance in patients undergoing allogeneic stem cell transplantation.

Intestinal dysbiosis has been associated with acute gastrointestinal GvHD and poor outcome following allogeneic stem cell transplantation (ASCT). To assess the effect of a switch in 2012 from ciprofloxacin/metronidazole to rifaximin for gut decontamination on intestinal microbiota composition and ASCT outcome, we retrospectively analyzed 394 patients receiving ASCT from September 2008 through June 2015. In 131 and 90 patients, respectively, urinary 3-indoxyl sulfate levels and intestinal enterococcal load were measured before conditioning and weekly within the first 28 days after ASCT. The use of rifaximin correlated with lower enterococcal positivity (6.9 vs 21.9%, P=0.05) and higher urinary 3-indoxyl sulfate concentrations (10.5 vs 4.6 μmoL/mmoL crea, P<0.001) after ASCT. Patients on rifaximin showed lower 1-year transplant-related mortality (P=0.04) and higher overall survival (P=0.008). Treatment of infectious complications with systemic antibiotics did not abrogate the beneficial effects of rifaximin on intestinal microbiota composition in the early course of ASCT and outcome. The data underscore the importance of maintaining a diverse population of symbiotic and mutualistic bacteria in the gut on ASCT outcome.

Allogeneic Stem Cell Transplantation Outcomes in Acute Myeloid Leukemia Patients with t(8;21)(q22;q22) in First Remission According to Conditioning Regimen

Allogeneic Stem Cell Transplantation Outcomes in Acute Myeloid Leukemia Patients with t(8;21)(q22;q22) in First Remission According to Conditioning Regimen

Granulocytic and Monocytic Myeloid-Derived Suppressor Cells May Have Different Role on Allogeneic Stem Cell Transplant Outcomes

Background: Myeloid-derived suppressor cells (MDSC), a heterogeneous group of myeloid cells, have emerged as immune regulators, having a high potential to suppress T cell responses. Although uniform characterization of human MDSC needs to be elucidated, they can be divided into the categories of granulocytic (G-MDSC) and monocytic (M-MDSC). Recent studies have reported that MDSC, generated in vitro or in vivo, alleviated the severity of graft-versus-host disease (GVHD) in murine allogeneic transplant models and in human delayed M-MDSC reconstitution was associated with the occurrence of acute GVHD. However, whether G-MDSC and M-MDSC may have different role on the outcomes after allogeneic stem cell transplantation (SCT) remains obscure.Methods: This prospective study was aimed to identify the clinical implications of early G-MDSC and M-MDSC expansion as a predictor for the occurrence of acute GVHD (aGVHD), infections, CMV reactivation, and survival outcomes after allogeneic SCT. The peripheral blood samples from 130 patients with acute myeloid leukemia and myelodysplastic syndrome-refractory anemia with excess blasts, who underwent allogeneic SCT between Jan. 2013 through Oct. 2014 were taken at engraftment and analyzed by flow cytometry.Results: Seventy-eight men and 52 women were enrolled in this study. The median age was 45.5 years (range, 17-68). To compare the predictive role of MDSC for various transplants, the patients were grouped according to the median values of the frequency of G-MDSC and M-MDSC. High G-MDSC at engraftment was a potential factor promoting the occurrence of ≥ grade 2 aGVHD at 100 days (30.8% vs. 47.7%, P = 0.023), whereas high M-MDSC group had no difference in the occurrence of ≥ grade 2 GVHD compared that of low M-MDSC group. There was no difference in CMV reactivation, infection rate, and TRM according to G-MDSC recovery. In contrast, patients in the high M-MDSC group had a higher cumulative incidence of infection at 100 days (25.1% vs. 48.2%, P = 0.002), and TRM (6.4% vs. 22.6%, P = 0.018), compared with the patients in the low group. Ultimately, multivariate analyses reveal that high G-MDSC had a trend for the occurrence of ≥ grade 2 GVHD at 100 days (RR 1.72, 95%CI (0.95-3.11), P = 0.071) and high M-MDSC could predict a higher infection rate (RR 2.30, 95%CI (1.30-4.07), P = 0.004) and higher transplant related mortality (TRM) (RR 3.30, 95%CI (1.10-9.90), P = 0.033). In addition, high M-MDSC was associated lower event-free survival (P = 0.008).Conclusion: Our data demonstrated that the high G-MDSC in the peripheral blood at engraftment was associated with a trend toward higher incidence of aGVHD and high M-MDSC was an independent factor for infection and TRM. Discrepancy of the role of G-MDSC and M-MDSC after allogeneic SCT suggests that difference of MDSC reconstitution into the more differentiated subset may predict transplant outcomes, including aGVHD, infections, and TRM. DisclosuresNo relevant conflicts of interest to declare.

Multi-Center Analysis of the Effect of Disease Subtype and Minimal Residual Disease on Allogeneic Stem Cell Transplantation Outcomes in T-Cell Acute Lymphoblastic Leukemia (T-ALL)

Introduction:T-cell acute lymphoblastic leukemia (T-ALL) represents approximately 20-25% of all cases of ALL diagnoses per year. Given the rarity of T-ALL, there are limited data to guide the treatment of these patients, particularly as it relates to allogeneic stem cell transplantation (allo-SCT). Early thymic-precursor (ETP) ALL is a rare variant of T-ALL which expresses both myeloid and lymphoid markers, and has been associated with increased relapse and worse overall survival in some series. Minimal residual disease (MRD) is established as a prognostic marker for increased relapse in B-ALL, but its effect on T-ALL, particularly as it relates to allo-SCT, is less clear. We conducted a multi-center analysis of patients with T-ALL to determine the effect of T-ALL subtype and MRD on transplant outcomes to better guide decisions regarding therapy for this aggressive disease.Methods:Data from MD Anderson Cancer Center (MDACC), the National University Cancer Institute of Singapore, and the Oregon Health & Science University were reviewed. All patients with a diagnosis of T-ALL who received a first allo-SCT after January 1, 2000 were included in the analysis. Flow cytometry data were reviewed centrally at MDACC to determine the T-ALL subtype. ETP was defined according to Coustan-Smith et al. (Lancet Oncol 2009;10:147-56). T-ALL subtype was determined using a similar system based upon Ludwig (Leuk Lymph 1994: 13:Suppl 1: 71-76) and Gassmann et al (Br J Haem 1997:97:372-82). MRD was evaluated by flow cytometry within one month prior to allo-SCT on bone marrow biopsy, and was detected with a sensitivity of 10-3. Overall survival (OS) and progression free survival (PFS) were estimated using the Kaplan-Meier method. Disease progression, acute GVHD (aGVHD), and chronic GVHD (cGVHD) were determined utilizing the cumulative incidence (CI) method to account for competing risks. Prognostic factors for OS were assessed using Cox Proportional Hazards regression analysis on univariate and multivariate analysis.Results:103 patients received first allo-SCT, with a median age of 31 years (range 2-72 years), and median follow-up time of 2.2 years (3.4-7.3 years). Of these, 91 had an identifiable subtype. The 3-year OS, PFS, CI NRM and CI progression was 34%, 31%, 11%, and 58% for the whole cohort, respectively. The CI 100-day NRM was 5%, while the incidence of grade II-IV aGVHD was 48% and CI cGVHD was 29% at 3 years. There was no difference in OS or NRM amongst T-ALL subtypes, including ETP (p=0.8), (Table 1). Furthermore, there was no difference in the rate progression of ETP (HR 1.5 (0.6-3.3, p=0.4).Amongst patients transplanted after 2007, when flow cytometry for MRD was widely utilized, 66 patients had available data: 41 MRD negative, 17 MRD positive, and 8 with no CR defined by >5% marrow blasts. On univariate analysis for OS, there was no difference according to institution, age, disease status at transplant (CR1 vs CR2+), white blood count, presence of extra-medullary disease at diagnosis, presence of CNS involvement, stem cell source, TBI vs no TBI, cytogenetic risk (SWOG classification), or complex cytogenetics. No CR at transplant (HR 3.9, p=0.003) and MRD positivity (HR 2.5, p=0.015) were associated with worse OS.With a median follow-up time of 2 years, the OS rates for patients who were MRD negative, MRD positive, and no CR were 62%, 24%, and 12%, respectively (Figure 1), with CI of progression of 30%, 69%, and 87% respectively (Figure 2). On multivariate analysis, MRD positivity was strongly predictive of OS (HR 2.3, p=0.03) and PFS (HR 2.1, p=0.04).Conclusions:There is no difference in outcomes of patients with T-ALL according to disease subtype. In particular, patients with ETP-ALL who underwent allo-SCT had similar outcomes to other T-ALL subtypes, suggesting that allo-SCT may overcome this poor prognostic primary disease feature. MRD at transplant is the strongest predictor of disease progression and lower survival in patients with T-ALL, with outcomes comparable to those transplanted with active disease. Novel approaches pre-transplant and post-transplant are necessary to mitigate the poor prognostic impact of MRD in T-ALL.Table 1Outcomes of Allogeneic Stem Cell Transplantation According to T-ALL SubtypeSubtypen (%)OSHRp-valuePFSHRProgressionp-valueEarly30 (33)41%Ref41%RefRefCortical28 (31)26%1.30.424%0.81.80.1Mature17 (19)31%1.10.823%NE2.40.04ETP16 (17)29%0.90.822%0.91.50.4 [Display omitted] [Display omitted] DisclosuresBrammer:Celgene: Research Funding.

Variable Outcome of Allogeneic Stem Cell Transplant According to the Different Levels of Pre-Transplant Minimal Residual Disease, in Adult Patients with Acute Myeloid Leukemia

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<0.001) and DFS (66,5% vs <10%, p<0.001) advantage. In the category no. 3, even if the low numbers suggest caution in drawing any conclusions, the patients showed a similar poor outcome both after AuSCT or ASCT. In multivariable analysis, backward, forward and stepwise regressions confirmed the role of ASCT vs. AuSCT (OS: HR 0.53, SDF 95% 0.30-0.95, p=0.039; DFS: HR 0.40, SDF 95% 0.23-0.70, p=0.001) and MRDpos vs MRDneg status (OS: HR 1.89, SDF 95% 1.03-3.46, p=0.032; DFS: HR 2.20, SDF 95% 1.24-3.93, p=0.007). These preliminary results indicate that in pre-transplant MRD positive patients the log-term outcome of ASCT may be different according to the amount of RLC. In low tumor burden (< 1%) MRD positive patients, conditioning regimens and GVL effect can still offer a chance of cure similarly to MRD negative patients. In high tumor burden (>1%) MRD positive patients, ASCT does not guarantee a long-term control of leukemia and further reduction of relapse risk is expected to be facilitated by novel strategies. DisclosuresNo relevant conflicts of interest to declare.