Incidence Of Acute GVHD Research Articles

Outcomes of Patients with T-Lymphoblastic Lymphoma Undergoing Allogeneic Stem Cell Transplantation: Retrospective Results from a Single Center

Background: T-lymphoblastic lymphoma (T-LBL) is a highly aggressive non-Hodgkin lymphoma seen in young adults that usually presents with a mediastinal mass and less than 20% bone marrow involvement with neoplastic cells. T-LBL and T-cell ALL are morphologically and immmunophenoytpically similar and are thus frequently grouped together. However there are differences in clinical presentation, cytogenetic features and molecular pathogenesis indicating biologic differences. Patients with relapsed refractory T-LBL have poor prognosis and there is a paucity of data on allogeneic HCT (allo-HCT) outcomes in this setting. Methods: We retrospectively reviewed medical records of 25 consecutive patients with T lymphoblastic lymphoma without prior auto-HCT who underwent allo-HCT at City of Hope from January 2000 to June 2018 after IRB approval was obtained. Descriptive statistics were used to summarize baseline patient demographic, treatment, and disease characteristics. Kaplan-Meier curves and the log-rank test were used to evaluate the overall survival (OS) and progression-free survival (PFS). Cumulative incidences of time to relapse and time to non-relapse mortality (NRM) were calculated with relapse and NRM as competing risks. Cumulative incidences of acute and chronic GVHD were calculated as time to onset of GVHD with relapse and death as competing events for GVHD. Results: 25 patients were included for the analysis. Median age at the time of allo-HCT was 25 years (range 7-70 years). 21 patients (80%) received myeloablative conditioning: FTBI containing regimens (n=20) with FTBI/VP-16 being most commonly used(n=16) and one patient received Bu/Cy based conditioning; 4 patients received reduced intensity conditioning with Flu/Mel. Sibling HCT was performed in 12 patients (48%), while MUD HCT was performed in 13 patients (52%) with fully matched HLA unrelated donor in 9 (36%) and HLA mismatched in 4 (16%) patients. GVHD prophylaxis consisted of tacrolimus/sirolimus (n=10), tacrolimus or cyclosporine/MTX (n=7), tacrolimus/sirolimus/MTX (n=4) and others (n=4) Source of stem cells was PBSC in 19 (76%), bone marrow in 5 (20%), and cord blood in 1 (4%) patients. At the time of allo-HCT, there were a total of 11 (44%) patients in complete remission (CR1 n=4, CR2+ n=7), 9 (36%) patients in partial remission and unknown remission status (n=5). The median follow-up among survivors was 8.9 years (range 2.3-12.1). The 5- and 10-year PFS was 31% (95% CI: 14%-50%). The 5- and 10-year OS was 31% (95% CI: 14%-49%) (Fig.1). Cumulative incidence of relapses at 5 and 10 years were both 36% (95% CI: 18%-55%) while NRM at 5 and 10 years was 33% (95% CI: 15%-52%). At day 100 after allo-HCT, the rates of acute GVHD grade II-IV were 63% (95% CI: 39%-79%) and grade III-IV of 25% (95%CI: 10%-44%). Chronic GVHD rates at 3 years were 60% (95% CI: 37%-77%). In univariate analysis, preHCT remission status did not improve PFS on long term follow up. Conclusions: Our results in patients with T-LBL shows 5-year PFS and OS of 31%, respectively, indicating that a subset of patients can be cured with allo-HCT in the high-risk setting. Disclosures Salhotra: Celgene: Other: Research Support; Kadmon Corporation: Other: Non paid consultant. Popplewell:City of Hope: Employment. Herrera:Kite Pharma: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Genentech, Inc.: Consultancy, Research Funding; Pharmacyclics: Research Funding; AstraZeneca: Research Funding; Immune Design: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy; Gilead Sciences: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding. Mei:Seattle Genetics, Inc.: Research Funding. Aldoss:AUTO1: Consultancy; Helocyte: Consultancy, Honoraria, Other: travel/accommodation/expenses; Jazz Pharmaceuticals: Honoraria, Other: travel/accommodation/expenses, Speakers Bureau; Agios: Consultancy, Honoraria. Zain:Seattle Genetics: Honoraria, Speakers Bureau; spectrum: Honoraria.

Sustained Donor Chimerism and Rapid Immune Cell Reconstitution Following Familial Haploidentical (FHI) CD34 Enriched Stem Cell Transplantation with Pbmnc Addback in Patients with High Risk Sickle Cell Disease (SCD) (IND 14359)

Background: Allogeneic stem cell transplantation (AlloSCT) from an HLA-matched sibling donor is the only known curative therapy in patients with high-risk SCD (Talano/Cairo, EJH, 2015). Unfortunately only about 15% of high risk patients with SCD have an HLA-matched unaffected sibling donor. T cell depletion has been employed to reduce AGVHD e.g., CD3/CD19 cell depletion (Barfiled RC, et al, Cytotherapy, 2004), αβ T-cell/CD19 cell depletion (Locatelli F, et al, Blood, 2017), CD34+ positive selection (Aversa F, et al, NEJM, 1998). MUD transplantation in high-risk SCD recipients has shown unexpectedly high rates of CGVHD (Shenoy et al, Blood, 2016). We reported a very low incidence of acute and chronic GVHD in pediatric recipients receiving CD34 enriched HPC products with PB MNC addback with 2 x 105 CD3/kg from MUD donors (Geyer/Cairo et al, BJH, 2012). Furthermore, rapid NK cell reconstitution after AlloSCT is associated with a significant improvement in 1yr OS (Pical-Izard, BBMT, 2015; Dunbar et al, Hematologica, 2008). Recently, we reported promising results for high-risk SCD patients at 1 year follow-up after FHI CD34 enriched/PBMNC with addback AlloSCT with the probability of 1-year overall survival (OS) n=17; 88.2% (CI95: 60.6-96.9) (Talano/Cairo, ASH, 2017), expanding the donor pool and hopefully improving outcomes for high-risk patients with SCD. Objective: To investigate donor chimerism, immune cell reconstitution and NK cell function in high-risk patients with SCD following AlloSCT using FHI CD34 enrichment/PBMNC (2 x 105 CD3/kg) addback. Methods: Twenty-one eligible SCD patients (2-<21 yrs) were enrolled. Nineteen patients received hydroxyurea, azathioprine, fludarabine, busulfan, thiotepa, cyclophosphamide, R-ATG, and TLI followed by FHI AlloSCT to date (Talano/Cairo, ASH, 2017). CD34 cells were enriched using the CliniMACS® system, kindly provided by Miltenyi Biotec, with a target dose of 10 x 106 CD34+ cells/kg with a PBMNC addback dose of 2x10*5 CD3/kg in the final product. Whole blood and RBC chimerism (estimated using CD71 to isolate an eythroid lineage-enriched fraction) were determined by STR. Immune cell and subset reconstitution was assessed by flow cytometry as previously described (Geyer/Cairo et al. BJH, 2012). NK function was determined by cytotoxic activity against K562 tumor targets at 10:1 E:T ratio by europium release assay and intracellular LAMP-1 (CD107a) and granzyme B expression by flow cytometry as previously described (Chu/Cairo et al, Can Imm Res, 2015). Results: There was 100% engraftment of neutrophils and platelets. The median day post-HISCT to neutrophil and platelet engraftment was +9 and +19, respectively. Whole blood donor chimerism (mean±SEM) at 1-year, 2-year, and 3-year post-HISCT was 97±1%, 97±1%, 97±1%, respectively (Fig.1). Donor chimerism for CD71+ RBCs (mean±SEM) at 1-year, 2-year, 3-year post-HISCT was 97±2%, 98±1%, 98±1%, respectively (Fig.1). Immune reconstitution of CD3, CD4, CD8, and CD19 was evaluated. The time to recovery of minimally normal levels post-HISCT of CD3 (800 cells/ul), CD4 (400 cells/ul), CD8 (200 cells/ul), and CD19 (200 cells/ul), was approximately 365, 365, 270, and 60 days post-HISCT (Fig.2), respectively. Probability of Grade II-IV AGVHD, CGVHD and 1 year EFS/OS was 6.2%, 6.7% and 90%, respectively. NK reconstitution was rapid and peaked at d+30 (36±9%, 2710cells/ml). NK cytotoxicity against K562 at a E:T=10:1 peaked at d+30 (26±3%) and d+180 (28±3%) vs at pre-t (16±2%) (p<0.01) (Fig. 3A). Consistent with increased NK cytotoxicity, CD56dimCD3- subset was increased at d+30 vs pre- HISCT (p<0.05). The NK activation marker, CD107a peaked at d+30 (38±9%) and d+180 (41±6%) (Fig.3B). More over, reconstituted NK cells expressed higher level of activating receptors NKp46 (24±9%), NKG2D (32±9%) and KIR2DS (8±3%) and inhibitory receptors NKG2A (33±9%), CD94 (28±9%) and KIR2DL2/3 (11±2%) at d+30 compared to other time points. Conclusion: Despite a 5 log depletion of T cells, the PBMNC addback (fixed at 2 x 105 CD3/kg) facilitated rapid donor chimerism and immune reconstitution with a low probability of Grade II-IV AGVHD. The rapid NK reconstitution may have in part contributed to the excellent 1yr OS in the FHI study. (Supported by FDA R01FD004090 (MSC)). Disclosures Cairo: Jazz Pharmaceuticals: Other: Advisory Board, Research Funding, Speakers Bureau; Osuka: Research Funding; Miltenyi: Other: MTA.

Myeloablative Fractionated Busulfan Conditioning Regimen in Older Patients: Results of a Phase II Study

Background: Traditionally, pre-transplant conditioning regimen is given over 4-6 days before hematopoietic cell transplant (HCT). Delivering higher dose chemotherapy preparative regimen over a longer time period has not been tested previously. We hypothesized that the delivery of myeloablative dose of busulfan over a 3-week period may reduce toxicity and non-relapse mortality (NRM), without affecting relapse, and tested this in a prospective phase II study. Methods: Patients between 18 and 70 years of age with hematological malignancies and adequate organ function, with 8/8-HLA matched related or unrelated donor were eligible. They received a fixed dose of busulfan 80mg/m2 as outpatient on days -20 and -13. Then, fludarabine 40mg/m2 was given on days -6 to -2 followed by busulfan dosed to achieve target area under the curve (AUC) of 20,000 mol/min for the whole course based on pharmacokinetic studies. GVHD prophylaxis was cyclophosphamide (PTCy) 50mg/kg on days 3 and 4 and tacrolimus. Mycophenolate mofetil (MMF) was added to later unrelated donor recipients. All patients received standard supportive care. The primary endpoint was day 100 NRM. Results: We enrolled 52 patients with a median age of 62 (range, 39-69) years. Almost half (n=25, 48%) had AML or MDS and the other half (n=26, 50%) had had CML or MPD; 1 (2%) had multiple myeloma. Low, intermediate, high and very-high disease risk index (DRI) was present in 3 (6%), 34 (65%), 14 (27%) and 1 (2%). HCT-comorbidity index was >3 in 23 (44%) and 1-2 (n=23, 44%). A majority (n=32, 62%) had an unrelated donor. With a median follow up of 14 months (range, 3-23), NRM at day 100 was 1.9% (n=1) and 8% (95% CI, 0-15) at 1 year. Overall survival, progression-free survival and relapse at 1-year were 83% (95% CI, 73-95%), 78% (95% CI, 67-91%), and 14% (95% CI, 4-24%), respectively [Table]. There were no graft failures. The median time to neutrophil engraftment was 17 days (range, 13-33) and that of platelets (> 20K/µL, n=45) was 24 days (range, 9-266). Day 100 grade II-IV and III-IV acute GVHD rates were 37% (95% CI, 23-50%) and 6% (95% CI, 0-12%), respectively; 1-year chronic GVHD and extensive chronic GVHD rates were 9% (95% CI, 0-17%) and 7% (95% CI, 0-14%), respectively. Overall survival at 1-year differed significantly among patients with low/intermediate DRI (94%; 87-100%) and those with high/very high DRI (53%; 31-91%), P=0.001. Conclusion: Myeloablative fractionated busulfan regimen with PTCy GVHD prophylaxis is feasible in older patients, has low incidence of severe acute GVHD, chronic GVHD, and NRM and results in promising overall survival. Table Disclosures Popat: Bayer: Research Funding; Incyte: Research Funding; Jazz: Consultancy. Bashir:Imbrium: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Spectrum: Membership on an entity's Board of Directors or advisory committees; StemLine: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Acrotech: Research Funding; Celgene: Research Funding. Ciurea:Miltenyi: Research Funding; Spectrum: Membership on an entity's Board of Directors or advisory committees; MolMed: Membership on an entity's Board of Directors or advisory committees; Kiadis Pharma: Membership on an entity's Board of Directors or advisory committees, Other: stock holder. Kebriaei:Amgen: Research Funding; Pfizer: Honoraria; Jazz: Consultancy; Kite: Honoraria. Nieto:Astra-Zeneca: Research Funding; Affimed: Research Funding; Affimed: Consultancy; Novartis: Research Funding. Oran:AROG pharmaceuticals: Research Funding; Astex pharmaceuticals: Research Funding. Qazilbash:Autolous: Consultancy; Bioclinica: Consultancy; Speaker: Other: Speaker; Amgen: Other: Advisory Board. Molldrem:M. D. Anderson & Astellas Pharma: Other: Royalties. OffLabel Disclosure: Fludarabine & Busulfan as conditioning agent prior to transplant

Equate, a Phase 1b/2 Study Evaluating the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Clinical Activity of a Novel Targeted Anti-CD6 Therapy, Itolizumab, in Subjects with Newly Diagnosed Acute Graft Versus Host Disease

Equate, a Phase 1b/2 Study Evaluating the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Clinical Activity of a Novel Targeted Anti-CD6 Therapy, Itolizumab, in Subjects with Newly Diagnosed Acute Graft Versus Host Disease

Fludarabine Melphalan Versus Fludarabine Treosulfan As Reduced Intensity Conditioning Regimens in Allogeneic Hematopoietic Stem Cell Transplant - a Retrospective Analysis

Introduction Allogeneic hematopoietic stem cell transplantation (AHSCT) has evolved as a curative therapy for various hematological malignancies. Regimen-related toxicity and transplant-related mortality (TRM) preclude the use of myeloablative conditioning (MAC) regimens in older and unfit patients. Reduced intensity conditioning (RIC) regimens have enabled AHSCT in such patients. There is a recent rise in use of RIC regimens even in younger patients in view of decreased toxicity and equal efficacy as reported in some studies. Fludarabine + Melphalan (FM) and Fludarabine + Treosulfan (FT) are 2 such regimens. There are no prospective randomised comparisons between these regimens. We retrospectively analysed these 2 regimens for toxicities and outcomes. Methods This is a retrospective single centre analysis of all consecutive patients with haematological cancers who received either FM or FT from April 2008 to December 2018. The entire cohort was divided into two groups - Matched Sibling Donor (MSD)/Matched Unrelated Donor (MUD) and Haploidentical (Haplo) transplants for analysis. We compared patient characteristics, toxicities and outcomes in both the groups based on conditioning regimen. The FT regimen consisted of fludarabine (30 mg/m2 on days − 6 to − 2) combined with treosulfan (12-14 gm/m2 on days − 6 to − 4) with or without 2 Gy TBI on day-1. The FM regimen consisted of fludarabine (30 mg/m2 on days − 7 to − 3) combined with melphalan (140 mg/m2 on day -1).Prophylaxis for GVHD consisted of calcineurin inhibitor (CNI) plus methotrexate (MTX)or mycophenolate mofetil (MMF) in MSD/MUD. Rabbit ATG (2.5-5 mg/kg) was used for MUD. Haplo transplant patients received post-transplant cyclophosphamide with CNI and MMF. Comorbidities were scored according to the HCT-CI. Disease Risk Index(DRI) and EBMT score were recorded for all patients. Neutrophil (NE) and platelet engraftment (PE) were defined as per standard criteria. Early toxicity after AHCT was graded according to CTCAE version 4. Total parenteral nutrition (TPN) was used in patients as per the physician's discretion. Acute GVHD and chronic GVHD were recorded according to standard criteria. All patients underwent chimerism studies at day 15, 30 and then monthly for 1 year. Mixed chimerism was defined as > 5% to < 95% donor chimerism. The toxicities in various arms were compared by Chi-square test or Fisher exact test, while OS was calculated by Kaplan Meier method and the survival probabilities were compared using log-rank test. Competing risk analysis was used to calculate cumulative incidence of relapse and TRM. Results The study included 138 patients, 98 males and 40 females. The diagnoses were AML- 53, ALL- 30, MDS/MPN- 49 and lymphoma -6. Patient characteristics are outlined in Table 1. MSD/MUD transplants were 105 (FM- 94; FT-11); 33 were Haplo (FM-17; FT-16) transplants. PBSC was the stem cell graft in 136 (99%) patients. In both MSD/MUD and Haplo groups, there were no significant differences in median age, gender, pre transplant CMV status, HCT-CI and EBMT score between the two conditioning regimens. In MSD/MUD group, significantly more patients had high/very high DRI in FT arm (45% vs 17%; P=0.056) Comparison of engraftment and toxicity variables of both FM and FT arms are outlined in Table 2. In MSD/MUD group, 44 (47%) patients in FM arm had grade 3/4 oral mucositis compared to 1 (9%) in FT arm (P=0.02). Corresponding numbers were 7 (41%) and 1 (6%) in Haplo group (P=0.039). Grade 3/4 diarrhoea was higher in the FM vs FT arm of Haplo group (41% vs 6%; P=0.039) but not in the MSD/MUD cohort. More patients received TPN in the FM arms of both MSD/MUD and Haplo groups (Table 2). Incidence of grade III-IV acute GVHD was higher in FT vs FM in MSD/MUD group (27% vs 17%; P=0.04). The median follow up of entire cohort was 4.8 years. The OS (figure 1) at 5 years was 62% in FM arm of MSD/MUD group vs 53% in FT arm (P=NS). Similarly OS (figure 2) at 5 years was 41% and 28 %( P=NS) in FM and FT arms respectively of Haplo group. The cumulative incidence of TRM and relapse at 2 years were not different in FM and FT arms of both MSD/MUD and Haplo groups (Table 2). Conclusion Grade 3 and 4 oral mucositis and diarrhoea were significantly less with FT than FM in both MSD/MUD and Haplo groups. FT provided comparable outcomes to FM in the MSD / MUD group in spite of having higher proportions of patients with high / very high DRI. Prospective randomised studies are required to compare various RIC regimens. Disclosures No relevant conflicts of interest to declare.

Predicting the Outcome in Egyptian Patients with Severe Aplastic Anemia Following Allogeneic Hematopoietic Stem Cell Transplantation Using Matched Sibling Donors

Patients presented with pancytopenia in the presence of bone marrow (BM) hypoplasia, aplastic anemia (AA), may get cured by specific medical care, if patients are under 40 years, mainly in the form of allogeneic hematopoietic stem cell transplantation (allo-HSCT) which is the treatment of choice for severe AA (SAA) in young age. In Egypt, SAA may get allo-HSCT only with availability of matched sibling (MSD). Success rate of allo HSCT-MSD is still suboptimal although it is a life challenging and expensive procedure with an outcome difficult to predict. Reports suggest that measurement of serum ferritin may help in predicting favorable MSD-alloHSCT outcome. Evidences showed that total infused CD34 cells and/ or measurements of hematogones (HGs) levels at the time of engraftment by flow cytometry may better predict the outcome of MSD-alloHSCT. HGs, normal B lymphocyte precursors, levels may be affected by the status of BM and humoral immunity. Elevated HGs have been noticed in healthy children, called reactive HGs. Regenerative HGs exist in non-malignant disorders such as autoimmune diseases, congenital cytopenia, acquired immunodeficiency and neoplastic disorders such as lymphoma. In addition they have been found in response to regeneration of humoral immunity post chemotherapy and post allo-HSCT. We aimed to examine predictive value of HGs in comparison to pre-transplant ferritin and/ or infused CD34⁺ counts for a favorable outcome of SAA patients treated with allo-HSCT from MSD. This is a prospective cross-sectional study, following institutional approval. In total 21 patients with SAA were consented and enrolled. All patients were treated with MSD allo-HSCT, between December 2013 and January 2016. Patients > 40years age, clinically unfit, with abnormal cytogenetic, diagnosed with inherited BM failure or paroxysmal nocturnal hemoglobinuria (PNH) were excluded. HGs were measured in BM samples at engraftment using flow cytometry where cells were stained with an anti-CD34, anti-CD38, anti- CD10, anti-CD19, and lineage (Lin) mixture (anti-CD3, -CD4, -CD8 -CD20, -CD14, and -CD56). Early HGs referred to both CD38ˉCD10⁺ CD19ˉCD34⁺ and CD38-CD10⁺CD19ˉCD34ˉ. Late HGs referred to CD38⁺CD10⁺CD19⁺CD34ˉ, and CD38⁺CD10ˉCD19⁺CD34ˉ cellss. The mean ± SD of early HG was 0.8 ± 1.6 and median with range was 0.05 (0-7.8) while mean ± SD of late HG was 0.6 ± 0.5 (p=0.4) and median with range 0.4 (0-1.4). Total HG mean ± SD was 0.7±1.2 and median with range 0.2 (0 - 7.8).Interestingly the mean ± SD of HG levels were higher in survivors vs non-survivors (2.3 ± 3.4 vs. 0.2 ± 0.2; P=0.01). Infused CD34 count (10^6) were in survivors vs non-survivors (6.7 ± 3 vs 7.8 ± 4) while pre-transplant serum ferritin levels (pm/mL) were in survivors vs non-survivors (1493 ± 1025 vs 1213 ± 371) without showing significant differences. Using ROC curve analysis, it showed the following for engraftment HGs%, best cut-off value was 0.37%, with AUC of 0.88, likelihood ratio (LR) of 3.85, it was the most sensitive 76.9% (95% CI; 35.4-84.8) and specific 80% (95% CI; 28.4 - 99.5) predicting favorable MSD-alloHSCT outcome. Infused CD34⁺ count showed best cut-off level of 6.8 x 10⁶ cells/kg, 0.63 for AUC, 3.13 for LR; 62% sensitivity (95% CI; 46.2-95) and 80% specificity (95% CI; 28.4-99.5). Pre-transplant serum ferritin showed best cut-off level of 1337, 0.59 for AUC; 1.6 LR; 64% for sensitivity (95%CI; 35.14 - 87.24) and only 60% specific (95% CI, 14.66 - 94.73). Moreover, patients with high HG (>0.37%; 57% vs. <0.37%;43%) had significantly high white cell count (WBCs); (median; 5 x 10⁹ /L, range; 2-9 vs 3.5,1.3-5; 95% CI; -3.5 to -0.1; p=0.03), absolute neutrophil count (ANC); (0.7 ± 0.4 vs 2 ± 0.8; p=0.0004), platelet; (26 ± vs 89 ± 46; p=0.001), at engraftment time in addition to superior OS (P=0.005). There was no difference in incidence of acute and chronic GVHD, infections or transfusion frequency rate among survivors with HGs below or above 0.37%. Noticeably donor age of transplanted patients with high HGs tended to be younger. Neither pre-transplant ferritin level nor infused CD 34⁺ count showed any impact on the OS (P=0.9 and 0.1 respectively). In sum HGs% FCM assay may be a highly sensitive and specific biomarker predicting HSCT outcome in SAA patients.. Estimating HGs% at engraftment time seem to be a promising predictor for the outcome of MSD-alloHSCT in SAA patients. SAA patients with HGs 0.37% or higher had better OS. Disclosures No relevant conflicts of interest to declare.

Complementary Transplantation Improved Results of Both Peripheral Blood Stem Cells and Unrelated Cord Blood Transplants in Thalassemia: A Multi-Center Study from China

Background: Unrelated cord blood (UCB) transplant (UCBT) is not recommended in patients with thalassemia major (TM) so far. Post-transplant (PT) Cyclophosphamide (PTCy) with long pre-transplant immunosuppression therapy have improved haploidentical peripheral blood (PB) stem cell transplant (haplo-SCT) survival in TM patients but with 2/31 primary rejection. So, we designed a novel dual transplantation of UCBT following haplo-SCTwith PTCy(NF-14-TM-CT protocol). Aim:To improve results of haplo-SCT and UCBT in patients with TM. Patients and method: NF-14-TM -CT protocol was termed as double-insurance dual transplantsincluding a haplo-SCT and an UCBT, in which conditioning regimen consisted of ATG (at -10 to -8 day), Cy (-7), Fludarabine (-6 to -2), Busulfan (-6 to -4) Thiotepa (-3), haplo-PB (0), PTCy (+3, +4) and UCB (+6). PTCy serve as GVHD prophylaxes after haplo-SCT and as conditioning before UCBT. In total 131 patients with TM from three pediatric center in China received NF-14-TM-CT protocolfrom June, 2014 to April, 2019, with a median follow-up of 13 (2-59) months and a median age of 8 (3.5-17) years. Results Final haplo-PB engrafted(group1)in 76 patients with mean PBSC-MNCof 22.49 (±5.36) x108/kgand UCB nuclear cells (NC) of 5.95 (±3.39) x107/kg and final UCB engrafted (group 2) in 55 patients with mean PBSC-MNC of 21.78 (±5.68) x108/kg and mean UCB-NC of. 5.43 (±2.32) x107/kg. The 4-year overall survival (OS), thalassemia-free survival (TFS), graft rejection (GR), and transplant related mortality (TRM) were 97.6%, 96.0%, 1.5%, and 2.4%, respectively (Fig. A), in total. The corresponding rates for group 1 were 98.3%, 96.9%, 1.7% and 1.8% and for group 2 were 95.5%, 93.8%, 4.5% and 1.4%, respectively. No statistic significant difference was found in OS, TFS, GR and TRM, respectively, when comparing group 1 with group 2 (Fig. B. C, D, E).The incidence of grade II-IV acute GVHD, III-IV acute GVHD, mild chronic GVHD, moderate/severe chronic GVHD, VOD, PT cystitisand PT hemolysis of the entire cohort was 16.8%, 6.87%, 9.92%, 1.52%, 4.60%, 31.3% and 14.5, respectively. Summary:Current study proved that the novel CT improved the results of haplo-SCT and UCBT in patients with TM. Disclosures Wing: Miltenyi Biotec: Employment.

Co-Transplantation of Mesenchymal Stem Cells Further Improves the Prognosis of Allo-HSCT in the Treatment of High Risk and Refractory/Relapse Hematologic Malignancies: A Single-Center Retrospective Study of 175 Patients

BACKGROUD: Mesenchymal stem cells (MSCs) are known to have immunomodulatory, anti-inflammatory and pro-angiogenic properties and thus have the potential to improve the likelihood of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of hematologic malignancies. OBJECTIVE: To explore the efficacy and safety of allo-HSCT by co-transplantation with MSCs in hematologic malignancies patients. METHODS: We conducted a single-center retrospective study to comparing the incidence and severity of acute GVHD, recurrence rate and overall survival (OS) of high risk and refractory/relapse hematologic malignancies patients undergoing allo-HSCT with or without co-injection of MSCs. A total of 175 patients (113males/62 females) at Fujian Medical University Union Hospital from January 2016 to June 2019 were analyzed. The median age of the patients is 22 (range 1-65 years). Patients received salvaged conditioning regimens FA5-BuCy as previous reported for high risk and refractory/relapse hematologic malignancies, registered on http://ClinicalTrials.gov (NCT02328950), among whom 31(17.7%)were MSD-HSCT, 21(12%) MUD-HSCT and 123(70.3%)haplo-HSCT. All patients received ATG, cyclosporine A with short course methotrexate for prevention of GVHD. 85 patients transplanted with donor HSCs only, and 90 patients transplanted with HSCs and MSCs .MSCs infusion dose was 1-2×106/kg, at -1~+1 days following HSCs infusion. RESULTS: The two groups were well matched demographically. All patients achieved successful engraftment within one month post-HSCT. There was no difference in time to leukocyte and platelet engraftment in the two groups. The incidence of aGVHD (36.5 % versus 26.7 %, P =0.163) was similar in the HSC versus MSC groups. With a median follow-up time of 373 days (range:29-1265days), the 2-yr OS was much better in MSC co-injection groups (77.6% versus 48.4%, P =0.005). Moreover, there was no significant difference in the 2-yr cumulative recurrence rate between the two groups (25.1% vs 16.2%, P = 0.4). CONCLUSION: FA5-BUCY as an intensive conditioning regimen facilitates the outcome of advanced diseases with allo-HSCT, and co-transplantation with MSCs could further improve the survival of hematologic malignancies patients who did not reach remission. Disclosures No relevant conflicts of interest to declare.

T-Cell Reconstitution after Unrelated Donor HSCT Using Immunotherapy with CD25/71 Allodepleted Donor T Cells: Results of the Randomised Icat Study

Karl S Peggs and Sarah J Albon contributed equally to the work and are joint first author Introduction Alemtuzumab reduces the incidence of GVHD after unrelated donor stem cell transplant (MUD SCT) but delays immune reconstitution resulting in high morbidity/mortality from viral infections. Previous studies have suggested that adoptive transfer of allodepleted donor T cells (ADTs) improves immunity after SCT but this has never been tested in a randomised study. We developed a methodology for selective immunomagnetic depletion of alloreactive T-cells upregulating CD25 and CD71 after activation with host dendritic cells (DC) and showed that ADTs retain anti-viral responses with minimal host alloreactivity (Samarasinghe et al Blood 2010). We have now tested whether ADTs can safely be used to improve immune reconstitution after MUD SCT for haematological malignancies in a randomised Phase II multi-centre clinical study; ICAT (NCT01827579). Methods Patients undergoing Alemtuzumab-based peripheral blood SCT from a 9/10 or 10/10 MUD for haematological malignancy were randomised 2:1 to receive either the ATIMP (ADTs) or standard of care. Two weeks prior to SCT, patients randomised to ATIMP underwent a leucapheresis from which DCs were generated. Irradiated patient-derived DCs were then co-cultured with peripheral blood mononuclear cells (PBMC) from an unstimulated leucapheresis/500ml blood draw from the donor to activate alloreactive T cells. Four days later, the co-culture was depleted of CD25+ and CD71+ fractions by immunomagnetic depletion on the CliniMACs, sampled for residual alloreactivity and sterility, and cryopreserved. Patients randomised to the ATIMP were scheduled to receive 3 escalating doses of ADTs (0.1x106/Kg at day 30, 0.3x106/Kg at day 60 and 1x106/Kg at day 90 post-SCT) until either there was >grade 1 aGVHD or they had normal circulating T cells (>700/µL). The primary end-point of the study was circulating CD3+ T cell count at 4 months post-SCT with one-sided 15% significance level. Acute/chronic GVHD were graded using the Seattle/NIH criteria respectively. Results Twenty one patients were treated, 13 on the ATIMP arm and 8 on the control arm. The median age was 53 years and 67% (14) were male. 12 were AML/Myelodysplasia, 5 NHL, 3 CLL/CML and 1 HL. The median follow-up time is 14 months. Five of 13 ATIMP patients received 1 dose of ADTs, 4/13 2 doses and 4/13 all 3 doses. The incidence of acute and chronic GVHD was comparable between the arms. Overall, 7/13 ATIMP patients developed significant (>Grade 2) acute GVHD compared to 4/8 of the control arm (p>0.99). 3/13 patients in the ATIMP arm and 2/8 patients in the control arm developed severe aGVHD (all Grade 3). Three of 13 ATIMP cohort patients developed chronic GVHD (1 mild, 1 moderate, 1 severe), compared to 3/8 (all mild) in the control cohort. At 4 months, the circulating CD3+ T cell count mean was 730/µL (range 10-4080) in the ATIMP group and 212.5/µL (range 10-500) in the control group (1-sided p=0.11). However, the data was not normally distributed (Wilcoxon 1-sided p=0.18). Three ATIMP patients had high CD3+ T cell count at 4 months (>1000/µL). At 6 months, the mean circulating CD3+ T cell count was 833.6/µL (range 20-2690) and 327.5/µL (range 10-860). At month 4, the mean PHA stimulation index in the ATIMP arm was 16.8 (range 0.67- 73.1) vs 3.8 (range 1.1-8.2) in the control group. At 4 and 6 months post-SCT, spectratyping analysis showed no evidence of a difference in Vβ diversity between the 2 arms in both CD4+ and CD8+ cells. The 1-year survival rate in the ATIMP cohort is 92% vs 88% in the control, and 1-year disease free survival rate 67% in the ATIMP cohort vs 70% in the control. Conclusions These data suggest that adoptive transfer of ADTs improves T cell reconstitution in some patients after MUD SCT and that the GVHD rates were similar between ATIMP and control groups. Figure 1: Kinetics of T cell recovery after transplant in ATIMP (blue) and Control (red) patients. Mean +/- SEM shown. Figure 1 Disclosures Peggs: Gilead: Consultancy, Speakers Bureau; Autolus: Membership on an entity's Board of Directors or advisory committees. Ghorashian:UCLB: Patents & Royalties: UCLB; Celgene: Honoraria; novartis: Honoraria. Amrolia:UCLB: Patents & Royalties.

Pilot Study on Frailty and Functionality on Routine Clinical Assessment in Allogeneichematopoietic Cell Transplantation to Predict Outcomes

Introduction: Frailty can adversely affect the outcomes of allogeneic hematopoietic stem cell transplantation (alloHSCT) but is difficult to measure in busy transplant clinics. The limited published studies have used dedicated trained persons and comprehensive geriatric assessment (GA) tools, which are time consuming (Muffly LS, Haematologica 2014; Holmes HM, J Geriatr Oncol 2014; Rodrigues M, J Geriatr Oncol 2019). The difficulty in application of GA tools by transplant clinicians, residents and nurses in their clinics has resulted in low adoption rates in routine practice. At our center we adopted selected tests for frailty and function which could be conducted during pre-transplant consultation in a busy clinic, without extra waiting time for patients, and using existing staff. The Timed up and Go test (TUGT) was adopted as it could be done in any closed clinic room, without need for a corridor. Thus it was considered safer than a gait speed test and was even applicable to patients in "isolation". We aim to share a preliminary analysis of the applicability and correlation between our selected frailty assessment with transplant outcomes and complications. Methods: Patients referred for transplant underwent the following assessments conducted by different providers. All ages were included. Relevant tests and source of data are as follows: Frailty and function by clinician evaluating (a) Clinical Frailty scale (CFS) with 9 points based on clinical judgement (Rockwood 2005) (b) Lawton's Instrumental activities of daily living (IADL). Objective physical performance by nursing BMT coordinator using (a) TUGT and (b) Grip strength using hydraulic "Jamar" hand dynamometer conducted in clinic room at time of documentation. Self assessment by patient completing (a) Self-rated health (SRH) question and (b) a question on falls. Blood tests (a) CRP (b) Albumin. The present study is a single center prospective observational study. Patients who did not proceed to transplant were excluded. Ninety-six consecutive adult allo-HSCT patients were eligible for the present analysis, updated on July 2019. The parameters were individually correlated with overall survival (OS), non-relapse mortality (NRM), cumulative incidence (cum.Inc) of acute GVHD, median time of transplant hospitalization and readmissions. Multivariate analysis was not performed in this pilot study due to limited number of patients and low frequency of adverse events. Results: Baseline characteristics and main post-transplant information are noted in Table 1. Median follow up of cohort was 5 months. Table 2 shows the main outcomes (with normal values). For the entire cohort the median OS at 6 months was 73.9% (range 61.7-82.8), NRM at day+100 was 8.7% (range 2.6-14.7), Cum.Inc of Acute GVHD 41.1% (range 30.1-52.1), Cum.Inc gr II-IV acute GVHD was 25.7% (range 15.6-35.9). Relapse occurred in 8 cases (8.3%) and deaths in 23 (23.9%). A TUGT of more than 10 seconds and raised CRP predicted poor OS (p<0.05). Abnormal TUGT, SRH question score of <A (excellent), lower albumin levels and raised CRP levels correlated with high NRM (p<0.05). A Clinical Frailty Score of more than 2, limitations of 1 or more IADLs, Grip strength below normal for age and sex, TUGT >10 seconds, SRH question <A, and lower albumin level were significant predictors for a longer median duration of transplant hospitalization. No frailty or functionality parameter correlated significantly with the Cum.Inc of any grade of acute GVHD, grade II-IV acute GVHD or the risk of rehospitalization after alloHSCT. Conclusions: Our pilot study shows that with selected brief tools, frailty and functionality can be assessed as part of routine clinical practice in allogeneic-stem cell transplantation in all age groups without extra waiting time for patients or additional human resources. TUGT is a useful prognostic tool which can be conducted in a clinic room and correlates with OS, NRM, and duration of hospitalization. Larger number of patients and longer follow-up will help to evaluate the different assessment modalities as prognostic tools in allo-HSCT and their wider applicability. Disclosures Michelis: CSL Behring: Other: Financial Support. Mattsson:Gilead: Honoraria; Celgene: Honoraria; Therakos: Honoraria.

Itolizumab As a Potential Therapeutic for the Prevention and Treatment of Graft Vs Host Disease

Background: CD6 is a co-stimulatory receptor, predominantly expressed on T cells, that binds to activated leukocyte cell adhesion molecule (ALCAM), a ligand expressed on antigen presentation cells and various epithelial and endothelial tissues. The CD6-ALCAM pathway plays an integral role in modulating T cell activation, proliferation, differentiation and trafficking and is central to inflammation. While effector T cell (Teff) are CD6hi and upregulate expression upon activation, regulatory T cells (Treg) remain CD6lo/-, making this an attractive target to modulate Teff activity while preserving Treg activity. Early studies by Soiffer and colleagues demonstrated using T12, an anti-CD6 monoclonal antibody (mAb) that ex-vivo depletion of CD6+ donor cells prior to transplantation decreased the incidence of both acute and chronic GVHD, highlighting the importance of CD6+ cells in GVHD pathogenesis and validating it as a therapeutic target. However, it remains to be shown whether modulating the CD6-ALCAM pathway in vivo can attenuate GVHD. We investigated the use of itolizumab, a humanized anti-CD6 mAb that has demonstrated clinical efficacy in other autoimmune diseases, as both a preventive and therapeutic treatment for GVHD, using a humanized xenograft mouse model. Methods: Humanized xenograft mice were generated by intravenous transfer of 2x10^7 human PBMCs into 6-8 weeks old NOD/SCID IL2rγ-null (NSG). To investigate the ability of itolizumab to prevent GVHD, mice were dosed with either 60μg or 300μg of itolizumab, 150μg of abatacept (CTLA4-Ig), or vehicle, starting one day prior to PBMC transplantation. To investigate the therapeutic effect of itolizumab, mice were dosed with either 150μg of itolizumab or vehicle, starting at Day 5 post-PBMC transfer, when transplanted T cells are already activated. All treatments were administered IP every other day. Weight and disease scores were monitored throughout the study. At Days 18 and 35, peripheral blood was evaluated by flow cytometry to examine T cell prevalence, and tissues were collected for histological examination of pathology and T cell infiltration. Results: When administered as prevention (Day -1), treatment with either 60μg or 300μg of itolizumab significantly decreased mortality compared to the vehicle control (100% vs. 10%); this decrease was similar to the positive control group treated with abatacept (Figure 1). At 60μg, itolizumab-treated mice demonstrated significant reductions in the prevalence of human T cells in peripheral blood vs. vehicle-treated mice at Day 18 (<0.2% vs. 74.5%; p < 0.001). The reduction in peripheral T cells was accompanied by reductions in tissue-infiltrating T cells in lung (85-fold) and gut (9.5-fold), as well as reductions in disease scores and weight loss. When administered therapeutically, treatment with itolizumab was associated with a survival rate of 50% compared to 10% in the control group (Figure 2). Similarly, peripheral T cell prevalence (34.3% vs. 65.1%; p < 0.001), weight loss, and disease scores were inhibited by itolizumab compared to vehicle control mice. Conclusions: These data suggest that systemic treatment with itolizumab can modulate pathogenic Teff cell activity, establishing this antibody as a potential therapeutic for patents with GvHD. A phase I/II study using itolizumab as first line treatment in combination with steroids for patients with aGVHD is currently ongoing (NCT03763318). Disclosures Ng: Equillium: Employment, Equity Ownership. Ampudia:Equillium: Employment. Soiffer:Mana therapeutic: Consultancy; Kiadis: Other: supervisory board; Gilead, Mana therapeutic, Cugene, Jazz: Consultancy; Juno, kiadis: Membership on an entity's Board of Directors or advisory committees, Other: DSMB; Cugene: Consultancy; Jazz: Consultancy. Ritz:Equillium: Research Funding; Merck: Research Funding; Avrobio: Consultancy; TScan Therapeutics: Consultancy; Talaris Therapeutics: Consultancy; Draper Labs: Consultancy; LifeVault Bio: Consultancy; Celgene: Consultancy; Aleta Biotherapeutics: Consultancy; Kite Pharma: Research Funding. Connelly:Equillium: Employment, Equity Ownership.

Investigating the Relationship between CD34+and CD3+ Cell Doses, One-Year Graft-Versus-Relapse-Free-Survival, Graft-Versus-Host Disease, and Overall Survival in Haploidentical Hematopoietic Stem Cell Transplantation: A Single Center Experience

Background: Haploidentical hematopoietic cell transplantation (haplo-HCT) has emerged as a popular alternative to traditional HLA-matched hematopoietic cell transplant. As the number of haplo-HCT's rises, investigating the factors that may affect outcomes is necessary in order to improve overall survival and reduce transplant-related mortality. The optimal dose of CD34+ cells used during haplo-HCT to ensure favorable outcomes using PTCy has not yet been reported though a range of 2 to 5.00x106 cells/kg is commonly used.Furthermore, the optimal dose of CD3+ cells is unknown however recent data has suggested less than 3.00x108 cells/kg may prevent the development of acute GVHD. The importance of studying the impact of CD34+/CD3+ cell dosing may help to improve outcomes in this setting. Methods: We retrospectively analyzed adult patients at USC Norris Cancer Hospital (age ≥ 21) who received haplo-HCT from 2014 to 2019. The primary end-point assessed was 1-year GVHD-free/relapse-free survival (GRFS) defined as grade 3-4 acute GVHD, systemic therapy-requiring chronic GVHD, relapse, or death in the first post-HCT year. Secondary end-points included 1-, 2-, and 3-year relapse-related mortality (RRM) and overall survival (OS) in addition to 1-year transplant related mortality (TRM) and incidence of both acute and chronic GVHD. Results: A total of 67 adult haplo-HCT recipients were reviewed. Of the patients evaluated, approximately 50% (n = 33) were male and 49% (n = 32) were female. The age range was 21-71 years old (median = 44), and the most common underlying hematologic disorders included AML (40%), ALL (38%), aplastic anemia (7.7%), and others (MDS, lymphoma, myelofibrosis, and HLH) (13.8%). 67% of patients received myeloablative conditioning regimens while 33% received reduced intensity regimens. 70% (n = 47) of patients received peripheral blood as a stem cell source with 30% (n = 20) receiving bone marrow. The mean CD34+ dose infused was 6.07x106 cells/kg and the mean CD3+ dose was 2.94x108 cells/kg. The mean time to recovery of platelets, neutrophils, and lymphocytes was 25, 18, and 37 days respectively. CD34+ stem cells ≥5.00x106 cells/kg was significantly associated with shorter time to lymphocyte recovery (p = 0.0265) though recovery less than 30 days was not significantly associated with OS (p = 0.5268). Incidence of 1-year GRFS was 71% (n= 46) and 1-, 2-, and 3-year RRM were 4.6%, 6%, and 7.7% respectively. 1-year TRM was 15.3% with 50% of deaths from acute GVHD. 1-, 2-, and 3-year OS were 80%, 78%, and 77% respectively. Factors significantly associated with increased mortality included use of RIC regimen (p = 0.004) and disease status at time of transplant (p = 0.04). Cumulative incidence of GVHD was 63% (n = 42) with 33% (n = 22) and 30% of patients (n = 20) with acute and chronic GVHD respectively. Lack of mild chronic GVHD was associated with increased mortality (p = 0.0029) and use of a myeloablative regimen (p = 0.0029) was significantly associated with GVHD. Subgroup analysis of those who received CD34+ dose ≥7.00x106 cells/kg (n = 24) and ≥10x106 cells/kg (n = 7) were found to have 1-year OS of 87.5% and 85.7% compared with 77% and 80% in those that received lower doses (p= 0.2229 and p = 1.00) respectively however this was not found to be significantly associated with increased incidence of GVHD, relapse, or mortality. Discussion: Our results demonstrate improved outcomes specifically 71% survived 1 year without experiencing at least 1 GRFS event compared with 24-35% reported by CIBMTR, Holtan et al 2015, and Solh et al 2016 with 3-year OS of 77% when compared with a previously reported 48%. The mean CD34+ cell dose of our population is higher than the standard range which may account for the improved outcomes however the dosing of CD34+/CD3+ cells were not significantly associated with our primary and secondary end-points. It was significantly associated, however, with shorter time to lymphocyte recovery, a factor that has been reported to be associated with decreased RRM and therefore improved OS. Furthermore, subgroup analysis of higher CD34+ dose did show a better 1-year OS though this was not statistically significant. Limitations of this study include small sample size and short follow-up period. Further research with a prospective study identifying the optimal CD34+/CD3+ cell dose in addition to comprehensive evaluation of immune recovery is warranted in order to improve haplo-HCT outcomes. Figure Disclosures Yaghmour: Jazz Pharmaceutical company: Consultancy, Speakers Bureau; Astella company: Speakers Bureau; Takeda: Speakers Bureau.

Risk Factors and Outcomes of Klebsiella Pneumoniae Infection before and after Allogeneic Hematopoietic Cell Transplantation

Introduction: Carbapenemase-producing (KPC) Klebsiella pneumoniae (Kp) infections have emerged as a major healthcare concern worldwide. Although infections are recognized as a major contributor of morbidity and mortality before and after allogeneic hematopoietic cell transplantation (HCT), the burden of Kp infections has not been extensively evaluated. Therefore, we aimed to determine risk factors and outcomes of these infections in HCT recipients. Methods: We retrospectively studied consecutive patients with Kp colonization and/or infection before and/or after HCT performed in 2008-2018. Patients were transplanted according to standard operating procedures of our JACIE-accredited center. Colonization was defined as the isolation of the microorganism from any non-sterile body site in the absence of clinical signs or symptoms of disease. Patients with colonization or infection pre-transplant received secondary prophylaxis pre and during transplant. Nurses, visitors and staff were carefully trained on infection control measures such as contact precautions and intensified hygienic measures in patients with pre-transplant isolation. Statistical analysis included the following factors: age, gender, disease phase at transplant (early, intermediate or advanced), donor, pre-transplant and post-transplant Kp infections and colonizations, KPC-Kp, severe acute and extensive chronic GVHD, relapse, treatment-related mortality (TRM) and overall survival (OS). Results: We studied 52 patients with a median age of 42 (range 17-42). Colonizations were detected in 9 patients pre-transplant (17%) and 29 post-transplant (56%); whereas infections in 23 pre- and 28 post-transplant (44% and 54%, respectively). KPC-Kp was isolated in 12 patients (29%). With a median follow-up of 23.5 months (range 1-99), cumulative incidence (CI) of severe acute GVHD was 44.5% and severe chronic GVHD 56.7%. Two-year CI of TRM was 14.3% and was independently predicted by the isolation of KPC-Kp (p=0.040, Figure 1A) and chronic GVHD (p<0.001). Among pre-transplant and transplant factors, acute GVHD was associated only with pre-transplant Kp infections (p=0.049). Pre-transplant infections were also associated with post-transplant infections (p=0.010), despite secondary prophylaxis. Overall survival was associated with disease phase at transplant (p=0.017), post-transplant infections (p=0.034) and acute GVHD (p=0.013). In the multivariate model, only post-transplant Kp infections independently predicted OS (beta=9.042, p=0.008, Figure 1B). Conclusions: Our study highlights the significant impact of Kp infections on TRM and OS of HCT recipients. In our population of patients with Kp colonization and/or infection, the burden of GVHD was high. Acute GVHD was linked with pre-transplant Kp infections, suggesting that disruption of intestinal microbiota may be an underlying predisposing condition. Secondary prophylaxis did not improve rates of post-transplant infections, but allowed the performance of HCT with an acceptable TRM rate. Our data suggest that additional interventions need to be further investigated to address the major problem of Kp infections in HCT. Figure 1 Disclosures No relevant conflicts of interest to declare.

Stem Cell Transplantation for Diamond-Blackfan Anemia. a Retrospective Study on Behalf of Severe Aplastic Anemia Working Party of the European Blood and Marrow Transplantation Group (EBMT)

Bader: Riemser, Neovii: Research Funding; Medac: Patents & Royalties, Research Funding; Amgen (Brasil), Novartis: Consultancy, Speakers Bureau; Celgene: Consultancy. Risitano:Alexion: Honoraria, Research Funding, Speakers Bureau; Achillion: Research Funding; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Apellis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Biocryst: Membership on an entity's Board of Directors or advisory committees; Alexion: Honoraria, Research Funding, Speakers Bureau; Amyndas: Consultancy; Samsung: Membership on an entity's Board of Directors or advisory committees; Samsung: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amyndas: Consultancy; Biocryst: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ra Pharma: Research Funding; Ra Pharma: Research Funding; Alnylam: Research Funding; Alnylam: Research Funding; Achillion: Research Funding. Peffault de Latour:Pfizer: Consultancy, Honoraria, Research Funding; Amgen: Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria, Research Funding.

Ptcy + ATG Compared to Ptcy Alone As Gvhd Prophylaxis for Peripheral Blood Stem Cells Allotransplant Is Associated with Significant Lower Incidence of Acute Gvhd without Increasing Relapse or Death By Infection

Backgound: High-dose post-transplant cyclophosphamide (PTCY) is currently used for GVHD prophylaxis both in the matched and the haplo transplant settings. However, peripheral blood stem cells (PBSC) as source of graft are significantly associated with a higher incidence of GVHD after transplant with PTCY compared to the use of bone marrow, especially with haplodonors. New strategies are needed to decrease GVHD incidence in this setting. Methods: This retrospective study included 115 adults (males n=68, median age: 60 yo (range: 23-71) allotransplanted with PTCY or PTCY+ATG between March 2014 and March 2019 in a single institution. Three conditionings were used: the Baltimore regimen (n=40, period: 11/2013-05/2017) consisting of Fludarabine 30 mg/m²/day (d), d -6 to -2, cyclophosphamide 14.5 mg/kg day -6, low dose total body irradiation 2 Grays d-1; the Clo-Baltimore regimen (n=37, period: 03/2014-04/2017), consisting of Clofarabine 30 mg/m²/d, d -6 to -2, cyclophosphamide 14.5 mg/kg d -6, low dose total body irradiation 2 Grays d-1; and the CloB2A1 regimen (n=38, period: 05/2017-03/2019) consisting of Clofarabine 30 mg/m²/d, d -6 to -2, busulfan 3,4 mg/kg d -3 and d-2, ATG 2,5 mg/kg d-1. The three groups shared most characteristics (gender, disease risk index, type of donor [matched vs haplo], ABO compatibility, donor/recipient CMV status, previous allograft, median age of the donor, median CD34+ and CD45+ graft cells counts). Baltimore patients were younger (median 56 years vs Clo-Baltimore: 61 years and CloB2A1: 60 years, p=0.02) and mostly transplanted for lymphoid diseases (65% vs 8% vs 19%, p<0.001). The median number of CD3+ T cells infused was significantly higher for CloB2A1 patients (27.5 107/kg vs Baltimore 22.65 vs Clo-Baltimore 20.8, p=0.008). All patients received PBSC as stem cell source at d 0 and PTCY 50 mg/kg/d, d +3 and +4 with cyclosporine and mycophenolate mofetyl as GVHD prophylaxis. All patients provided informed consent for data collection before the graft. Results: The median follow-up was 42 (29-64), 33 (7-63) and 15 (3-25) months for the Baltimore, Clo-Baltimore and CloB2A1 groups, respectively. Primary graft failure was significantly higher in the CloB2A1 group (at day+60: 22% (6 haplo, 1 10/10 and 1 9/10) vs Baltimore 5.2% (1 haplo, 1 10/10) vs Clo-Baltimore 0% (p=0.003). Similar 18-month survivals were observed for the three groups (Baltimore/Clo-Baltimore/CloB2A1): OS: 65% (51-81) vs 67.1% (53-84) vs 51.2% (35-73), p=0.27; DFS: 60% (46-77) vs 56.7% (42-75) vs 37.8% (23-62) p=0.20); GRFS (50% (36-68) vs 37.8% (25-57) vs 36.7% (22-60), p=0.63). The incidences of relapse and death as well as the causes of deaths (no more death by infection in the CLOB2A1 sub-group) were also comparable. Conversely, considering engrafted patients, the incidence of grade 2-4 acute GVHD was significantly lower in the CloB2A1 sub-group (19% vs Baltimore: 50% vs Clo-Baltimore: 51.4%, p=0.009) and despite higher numbers of CD3+ T cells infused in this group. The incidence of grade 3-4 acute GVHD and chronic GVHD (considering engrafted patients alive at day+100) was lower also in the CloB2A1 sub-group (6.2% vs 16.6% vs 13.5%, p=0.32 and 16% vs 29.4% vs 31%, p=0.51). Considering only haplotransplants, 18-month OS (p=0.95), DFS (p=0.98) and GRFS (p=0.39) were similar between the three groups (Baltimore: 57.1%, 50% and 35.7%; Clo-Baltimore: 60%, 53.5%, 35.7%; CloB2A1: 57.9%, 48.3%, 46.6%). The incidence of grade 2-4 acute GVHD remained significantly lower in the CloB2A1 haplo sub-group (p=0.01). Considering only matched transplants, 18-month survivals were significantly lower for the CLoB2A1 sub-group (OS: 44.4% vs Baltimore 83.3% vs Clo-Baltimore: 88.8%, p=0.05; DFS: 33% vs 83.3% vs 66.6%, p=0.008; GRFS: 22.2% vs 75% vs 44.4%, p=0.008). Conclusion: The CloB2A1 + PTCY regimen does not appear to be a good platform, neither for haplotransplant nor for matched transplant since 1) the incidence of primary graft failure is relatively high for the former and 2) survivals are lower for the latter. However, this study shows that the addition of one day of ATG to PTCY decreases the incidence of GVHD after transplant without increasing the incidence of relapse or death by infection. The use of ATG +PTCY should be tested in patients receiving PBSC haplo-transplant but with other conditioning regimens allowing for a good engraftment, such as Baltimore-based regimens. These data have to be validated prospectively. Disclosures Chevallier: Incyte: Consultancy, Honoraria; Daiichi Sankyo: Honoraria; Jazz Pharmaceuticals: Honoraria. Peterlin:Daiichi-Sankyo: Consultancy; AbbVie Inc: Consultancy; Astellas: Consultancy; Jazz Pharma: Consultancy. Le Gouill:Janssen-cilag: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Roche Genentech: Consultancy, Honoraria; Gilead-Kite: Consultancy, Honoraria; Servier: Consultancy; Novartis: Consultancy; Takeda: Consultancy; loxo: Consultancy, Honoraria. Moreau:Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria.

Allogeneic Hematopoietic Stem Cell Transplantation for T Cell Lymphomas: Improved Results Overtime

INTRODUCTION: Allogeneic hematopoietic stem cell transplantation (alloSCT) is the only curative strategy for relapsed/refractory T cell lymphoma (T-NHL). In the past ten years, there have been several improvements in conditioning regimens and graft versus host disease prophylaxis (GVHD), which have contributed to lower transplant-related mortality (TRM). Also, selective and low toxicity therapies, might improve response quality in some T-NHL Recently, haploidentical stem cell transplantation (Haplo) with post-transplant cyclophosphamide is a new option for those patients who do not have an HLA-identical sibling or a suitable unrelated donor, but also it has shortened the time for urgent cases. METHODS: This study analyzes overall outcomes of 211 consecutive patients diagnosed with T-NHL who received an alloSCT from 1995 to 2018 in GELTAMO/GETH centers. Previous therapies (chemotherapies and autologous stem cell transplantation) and baseline diagnostic parameters were recorded. RESULTS The median age at alloSCT was 47 years (range, 17-69). (see table 1). Forty-nine (23%) had primary extranodal disease. Disease status pre alloSCT was available in 202 patientes: 54% were in complete response (CR), 30% in partial response (PR) and 16% with stable/progressive disease (PD). Since 2013 BV was used as a bridge therapy in ≥ 3rd line in 25 patients with CD30+ tumor expression, it was effective in 20 (CR 68% (n=17), PR 12% (n=3) PD 16% (n=4), not assessed in 1 case). The use of BV was not associated with a better response probability pre alloSCT compared with other regimens used after third line and it did not impact on post alloSCT outcomes. Reduced intensity conditioning (RIC) was the most frequent (76%, n=156). (see table 2) GVHD prophylaxis were Methotrexate + CsaA or Tacrolimus (n=72, 35,8%), sirolimus-tacrolimus (n=37; 18,4%), Cy-post based (n=44, 21,9%; used in Haplo setting n= 29). The median follow-up of all cohort was 22.5 months (range, 0-280). The two year overall survival (OS) and disease free survival (DFS) were 60% (CI95%, 53-67%) and 76.7% (CI95%, 69.3-82.5%) (Figure 1A) We observed a significant improvement in alloSCT outcomes since 2011 (OS <2011 51.4% vs ≥2011 64.8%, p=0,04).(Figure 1B) Disease status was the only pre alloSCT variable that impacts 2 years - OS: CR 72.8% (CI95%, 63-80.4%), PR 52%(38.7-63.7%), PD 43.8 (26.5-59.8%) (p=0.002) (Figure 1C). Forty-three (21%) cases relapsed after alloSCT. To analyze the impact of GVHD on OS and DFS we selected landmark time point at day +100 and +1 year after alloSCT for acute (aGVHD) and chronic GVHD (cGVHD) respectively, which allowed us to capture the majority of events that could interfere with the analysis. A landmark analysis (day +100) showed a 2 year OS for grade 3-4 aGVHD was 18% and for 1-2 aGVHD 54,6% (p<0,001). The severity of aGVHD had no impact on DFS. Different grades of cGVHD did not impact OS nor DFS significantly. Cumulative incidence of acute GVHD at 90 days was 51.6% (CI95%, 43.9-58.2%) being 27% grade 3-4. Chronic GVHD at 6 months was 53.9% (46.1-60.5), 54% of cases were grade 3-4). The 2 years non relapse mortality (NRM) was 30.2% (CI95%, 23.3-36.5%); the main causes contributing to NRM were GVHD (40%) and infections (44%) Haploidentical (Haplo) alloSCT was introduced in 2012 (29 of 128). With a median follow up of 13 months (range, 0-60) we found that outcomes in terms of 1 year OS (Haplo 60.7% vs. others 67,5%), 1 year DFS (Haplo 74.8% vs. others 83.8%) and 1 year NRM (Haplo 29.7% vs. 26%) are similar to other alloSCT modalities (Figure 1D). Not additional analysis could be estimated due to the low number of population at risk for each category. CONCLUSION Overall outcomes of alloSCT for T-NHL have improved over time. Complete response pre alloSCT is the only determinant for OS. Haploidentical alloSCT is not significantly different from other approaches and should be considered as an alternative. Disclosures Sierra: Novartis: Honoraria, Research Funding, Speakers Bureau; Astellas: Honoraria; Pfizer: Honoraria; Daiichi-Sankyo: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau; Roche: Honoraria; Jazz Pharmaceuticals: Honoraria.

Outcomes of Total Body Irradiation- Versus Chemotherapy-Based Myeloablative Conditioning Regimen in Haploidentical Hematopoietic Cell Transplantation with Post-Transplant Cyclophosphamide for Acute Myelogenous Leukemia: ALWP of the EBMT Study

Background The use of haploidentical hematopoietic cell transplantation (haplo-HCT) with post-transplant cyclophosphamide (PTCy) is rapidly increasing. The safety and efficacy of myeloablative conditioning (MAC) in haplo-HCT has been reported in patients with acute leukemia. However, optimal MAC in haplo-HCT setting is unknown. We studied the outcomes of total body irradiation (TBI) vs. chemotherapy (CT) based MAC regimens in acute myelogenous leukemia (AML) patients undergoing haplo-HCT and reported to the Acute Leukemia Working Party of the EBMT. Methods The study included 1008 AML patients (secondary AML=149, 15%) who underwent haplo-HCT with PTCy during the years 2010-2018, following TBI (n=89, 9%) or CT (n=919, 91%) based MAC. Regimen intensity was defined by EBMT criteria and cases with busulfan dose <9 mg/kg or TBI dose ≤6 gray were excluded. Baseline AML cytogenetic risk group was good, intermediate and poor in 8%, 65% and 27% of patients respectively. All pre-HCT disease status (CR1=434, 43%; CR2+=216, 21%; advanced=358, 36%) were included in the study. fludarabine- TBI (78%) and thiotepa- busulfan- fludarabine (56%) were the most common MAC regimens in TBI and CT-cohorts, respectively. Patients in the TBI cohort were more likely to be younger (median age, 38 vs. 47 yrs, p<0.01) and receive BM graft (57% vs. 43%, p-0.01) Other patient, disease, and transplant related characteristics were similar in both groups. Median follow up for TBI and CT cohort were 25.4 (IQR-9.5-58.7) and 20.7 (IQR-11.7-40.3) respectively. Results In univariate analysis, day 100 incidence of acute GVHD (aGVHD) II-IV and III-VI was 22% vs. 27% (p-0.44) and 12% vs. 12% (p-0.92) in TBI and CT cohorts respectively. Two-year total and severe chronic GVHD (cGVHD) incidence was 42% vs. 27% (p<0.01) and 9% vs. 12% (p-0.33) in TBI and CT cohorts respectively. More patients achieved neutrophil engraftment by day 30 in the TBI cohort (97% vs. 86%,p-0.05). Graft failure was reported in 2 (2%) and 65 (7%)(p-0.08) patients who received TBI and CT-based MAC respectively. There were 3 (1%) deaths related to graft failure in the CT-group. Death from veno-occlusive disease was reported in 1(3%) TBI pt and 11(3%) CT patients. The proportions of infection related deaths (TBI-29% vs. CT-32%) and GVHD related deaths (TBI-17% vs. CT-15%) were comparable. Death due to interstitial pneumonitis was reported in 1(3%) TBI and 8(2%) CT patients. Death from a second malignancy was reported in one pt in each group. In multivariate analysis, TBI was associated with a higher incidence of overall cGVHD [HR=1.81, 95% CI:1.14-2.87, p-0.01] compared to CT. There was no difference in other outcomes such as extensive cGVHD [HR=0.34, 95% CI:0.11-1.10, p-0.07], relapse incidence(RI) [HR=1.32, 95% CI:0.85-2.03, p-0.22], nonrelapse mortality(NRM) [HR=0.82, 95% CI:0.46-1.49, p-0.52] and leukemia free survival(LFS) [HR=1.09, 95% CI:0.77-1.55, p-0.62], overall survival(OS) [HR=1.07, 95% CI:0.74-1.56, p-0.71] and GVHD free relapse free survival (GRFS) [HR=1.02, 95% CI:0.74-1.40, p-0.92]. Two-year LFS and OS of TBI and CT cohorts were 45% vs. 49% (p-0.98) and 50% vs. 55% (p-0.79) respectively (Figure 1). Factors impacting OS were pt age (per 10yrs, HR=1.1, p-0.02), KPS ≥90 (HR=0.55, p<0.01) and advanced disease status before haplo-HCT (HR=2.35, p<0.01)(Table 1). Interestingly, cytogenetic risk groups had no impact on LFS or OS in this analysis. No interaction was observed between the type of MAC and RI, NRM, LFS, OS and GRFS in a separate subgroup univariate analysis of patients <40 yrs old and patients with pre-HCT disease status CR2 or advance disease. Conclusions In this large cohort of AML patients who received first haplo-HCT with PTCy, TBI based MAC was associated with higher incidence of overall cGVHD without impacting other transplant outcomes compared to CT based MAC. In the absence of a prospective study, these findings may guide clinicians when choosing an optimal MAC in haplo-HCT with PTCy. Disclosures Dholaria: Celgene: Honoraria. Labopin:Jazz Pharmaceuticals: Honoraria. Angelucci:Jazz Pharmaceuticals: Other: Local advisory board; Roche: Other: Local advisory board; Novatis: Honoraria, Other: Chair Steering Committee TELESTO protocol; Celgene: Honoraria, Other: Participation in DMC; BlueBirdBio: Other: Local advisory board; Vertex Pharmaceuticals Incorp., and CRISPR Therapeutics: Other: Participation in DMC. Blaise:Jazz Pharmaceuticals: Honoraria; Molmed: Consultancy, Honoraria; Sanofi: Honoraria; Pierre Fabre medicaments: Honoraria. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding.

Human leucocyte antigen diversity: A biological gift to escape infections, no longer a barrier for haploidentical Hemopoietic Stem Cell Transplantation.

Since the beginning of life, every multicellular organism appeared to have a complex innate immune system although the adaptive immune system, centred on lymphocytes bearing antigen receptors generated by somatic recombination, arose in jawed fish approximately 500 million years ago. The major histocompatibility complex MHC, named the Human leucocyte antigen (HLA) system in humans, represents a vital function structure in the organism by presenting pathogen-derived peptides to T cells as the main initial step of the adaptive immune response. The huge level of polymorphism observed in HLA genes definitely reflects selection, favouring heterozygosity at the individual or population level, in a pathogen-rich environment, although many are located in introns or in exons that do not code for the antigen-biding site of the HLA. Over the past three decades, the extent of allelic diversity at HLA loci has been well characterized using high-resolution HLA-DNA typing and the number of new HLA alleles, produced through next-generation sequencing methods, is even more rapidly increasing. The level of the HLA system polymorphism represents an obstacle to the search of potential compatible donors for patients affected by haematological disease proposed for a hematopoietic stem cell transplant (HSCT). Data reported in literature clearly show that antigenic and/or allelic mismatches between related or unrelated donors and patients influences the successful HSCT outcome. However, the recent development of the new transplant strategy based on the choice of haploidentical donors for HSCT is questioning the role of HLA compatibility, since the great HLA disparities present do not worsen the overall clinical outcome. Nowadays, NGS has contributed to define at allelic levels the HLA polymorphism and solve potential ambiguities. However, HLA functions and tissue typing probably need to be further investigated in the next future, to understand the reasons why in haploidentical transplants the presence of a whole mismatch haplotype between donors and recipients, both the survival rate and the incidence of acute GvHD or graft rejection are similar to those reported for unrelated HSCTs.

ST2 and REG3α as Predictive Biomarkers After Haploidentical Stem Cell Transplantation Using Post-transplantation High-Dose Cyclophosphamide.

Allogenic hematopoietic stem cell transplantation (allo-HSCT) is a curative procedure for several hematological malignancies. Haploidentical HSCT (haplo-HSCT) using high-dose post-transplantation cyclophosphamide (PTCy) makes transplantation possible for patients with no HLA-matched sibling donor. However, this treatment can cause complications, mainly infection, graft-vs.-host disease (GVHD), and conditioning-related toxicity. In recent years, different biomarkers in the form of tissue-specific proteins have been investigated; these may help us to predict complications of allo-HSCT. In this study we explored two such biomarkers, suppression of tumorigenicity 2 (ST2) and regenerating islet-derived 3α (REG3α), in the largest series reported of T cell–replete haplo-HSCT with PTCy. Plasma samples drawn from 87 patients at days +15 and +30 were analyzed. ST2 and REG3α levels at day +15 were not associated with post-transplant complications. ST2 levels at day +30 were higher in patients with grade II-IV acute GVHD, mainly those who received reduced intensity conditioning (RIC; median 2,503 vs. 1,830 ng/ml; p = 0.04). Of note, patients with higher plasma ST2 levels at day +30 also presented a higher incidence of non-relapse mortality (HR, 7.9; p = 0.004) and lower 2-year overall survival (25 vs. 44 months; p = 0.02) than patients with lower levels. Patients with REG3α levels higher than 1,989 pg/ml at day +30 presented a higher incidence of acute gastrointestinal GVHD in the whole cohort (HR, 8.37; p = 0.003) and in the RIC cohort (HR 6.59; p = 0.01). These data suggest that measurement of ST2 and REG3α might be useful for the prognosis and prediction of complications in patients undergoing haplo-HSCT with PTCy.

Cyclosporine A for the Prevention of Ocular Graft versus Host Disease in Allogeneic Hematopoietic Stem Cell Transplant Recipients Is Safe and Feasible

Purpose: To evaluate the safety and efficacy of ocular cyclosporine in the prevention of the development of ocular graft versus host disease (oGVHD) in patients undergoing allogeneic hematopoietic stem cell transplantation (AHSCT) in comparison with historic data. Design: We developed a longitudinal, observational, prospective nonrandomized study. We evaluated the feasibility of prophylactic use of topical cyclosporine A (CsA) to prevent or decrease the incidence of oGVHD and compared this with historic data. Methods: Patients undergoing AHSCT were treated with prophylactic topical CsA for 12 months after engraftment, followed by serial ophthalmic evaluations, including the Schirmer test. Results: Twenty patients were included. No serious adverse effects were reported. Poor adherence was documented in 15% of patients. In spite of observing extra-ocular GVHD (acute and chronic GVHD incidence of 50 and 45%, respectively), only 1 in 20 patients developed oGVHD over the 20-month follow-up for the entire cohort. No statistically significant difference was observed in the incidence of oGVHD when compared to a historical cohort. Conclusions: Topical CsA as a prophylactic measure for oGVHD, administered over a period of 1 year after grafting, is safe and feasible and may decrease the incidence of ophthalmic manifestations of GVHD. These findings must be confirmed in a randomized trial.