Anti-thymoglobulin Research Articles

#1286 Utility of cinacalcet treatment in kidney transplant recipients with persistent hyperparathyroidism

Abstract Background and Aims Secondary hyperparathyroidism occurs in the majority of patients with chronic kidney disease (CKD). It may persist in up to 50-66% of patients despite the initial decrease in PTH levels after successful kidney transplantation (KT). Maintaining parathyroid hormone (PTH) levels within the normal range during the post-transplant period is crucial because it is related to hypercalcemia, hypophosphatemia, and reduced bone mass in KT recipients. Studies have already demonstrated that persistent hyperparathyroidism is associated with graft loss and all-cause mortality. Vitamin D, vitamin D analogs, and calcimimetics are most commonly used to manage hyperparathyroidism. However, studies about the long-term effect of calcimimetic therapy on the allograft are still limited. In this study, we aim to investigate the long-term allograft results of patients who received cinacalcet treatment for hyperparathyroidism. Method This study was conducted in Gazi University nephrology dialysis and transplantation unit with 312 patients who were transplanted between 1996 and 2019 and continued routine follow-up visits. Persistent hyperparathyroidism is defined as elevated PTH levels after the first year of KT (serum PTH>88 pg/mL). All patients without concurrent hypercalcemia were treated with vitamin D or analogs according to their vitamin D levels. Patients with non-functional allograft and parathyroidectomy after KT were excluded from this study. In addition, patients with rejection episodes, which could be confounding factor for allograft survival, were excluded to evaluate the isolated effect of cinacalcet on the allograft function. We identified 115 patients with persistent hyperparathyroidism, of whom were treated with cinacalcet (n = 21) or not (n = 94). We analyzed the baseline characteristics, comorbidities, and immunosuppressive treatments of the groups. Additionally, annual eGFR changes (Δ eGFR) calculated based on baseline (post-transplantation 6th month) eGFR after KT was also examined to evaluate the effect of cinacalcet on the graft. Results The mean age of the patients was 44.3 ± 12.6 years, and 47 (41%) were women. The median follow-up time of the patients was 87 (49-117) months. Twenty-nine patients (25%) underwent cadaveric transplantation, and 47 (41%) patients received anti-thymoglobulin (ATG) in induction therapy. While all patients were given glucocorticoids as maintenance immunosuppressive therapy, 93 (81%) of the patients received tacrolimus and, 9 (8%) cyclosporin as CNI, 78 (68%) received anti-metabolite therapy. Fifty-eight patients (19%) were used mTORi. A total of 21 patients with persistent hyperparathyroidism (21%) were treated with cinacalcet. Dialysis time is longer in the cinacalcet-treated group than in the patients not treated with cinacalcet (p < 0.001). The preemptive transplantation rate was lower (p = 0.03), and the delayed graft function was higher in the cinacalcet-treated group (p = 0.04). In the first year after KT, serum median PTH levels were 227 (167-341) pg/ml in the cinacalcet group and 110 (86-160) pg/ml in the other group, respectively (<0.001). Also, serum phosphate level is lower in the treatment group (2.7 ± 0.4 mg/dl vs. 3.1 ± 0.7 mg/dl, p = 0.03). At the last visit of patients, we observed similar median PTH levels between groups [141 (100-222) vs. 108 (73-159), p = 0.08]. During the follow-up, CMV episodes and BKV nephropathy diagnosis rates were similar between the groups (Table 1). Δ eGFRs in the first year (p = 0.7), second year (p = 0.2), third year (p = 0.4), and fifth year (p = 0.6) after KT were similar between both groups. Conclusion Our study suggests that cinacalcet treatment could be a safe and effective treatment for patients with persistent hyperparathyroidism. In long-term follow-up, there is no evidence of a reduction of kidney function. However, more trials are still required for other clinical outcomes such as fracture risk and cardiovascular morbidity and mortality.

Improved Gvhd-Relapse Free Survival of Ex Vivo αβtcr/CD19 Depleted Allo-Sct Combined with In Vivo T Cell Depletion with ATG When Compared to T Cell Replete Transplantations with or without the Addition of ATG

Introduction The aim of allogeneic stem cell transplantation (allo-SCT) is to reach graft-versus-host disease, relapse free survival (GRFS). To reduce the incidence of graft-versus-host disease (GVHD), we have developed an allo-SCT platform combining ex vivo αβTCR/CD19 depletion with in vivo T-cell depletion through administration of antithymoglobulin (ATG). Here we compare GRFS to historical cohorts of T-cell replete allo-SCT. Methods Adults with hematological malignancies and transplanted between 2011 and 2022 were included in this retrospective analysis. Written informed consent was obtained in accordance with the JACIE guidelines. Clinical data was extracted from the EBMT registry. 3 cohorts were identified. Cohort A: Allo-SCT of unmanipulated peripheral blood derived mononuclear cells (PBMCs) of matched related donors (MRD) after non-myeloablative (NMA) or myeloablative (MA) conditioning without ATG. Cohort B: Allo-SCT of unmanipulated PBMCs of 10/10 or 9/10 matched unrelated donors (MUD) after NMA or MA conditioning with ATG. Patients in cohorts A & B received dual immunosuppression with cyclosporin (CsA) and mycophenolic acid (MMF). Cohort C: Allo-SCT of αβTCR/CD19 depleted PBMCs of MRD and MUD (10/10 and 9/10) after ATG and a myeloablative conditioning as previously described[1]. Patients in cohort C received 28 days of MMF. Cumulative incidence (CI) of GVHD was defined as time to onset of GVHD, with relapse and death as competing events. Overall survival (OS) was defined as time to death from any cause. CI of relapse was defined as time to relapse, with death as a competing event. Non-relapse mortality (NRM) was defined as time to death, without relapse or progression. Event free survival (EFS) was defined as the time to relapse, graft failure or death. GRFS was defined as the time to relapse, aGVHD 3-4 or extensive cGVHD, graft failure or death. CI of CMV and EBV reactivations were calculated with relapse and death as competing events. Results 341 patients were included (cohort A: N=63; cohort B: N=150; cohort C: N=128) (table 1). In T cell replete allo-SCT (A&B) ATG was administered to recipients of MUD and MA conditioning was administered to patients < 40 years with acute leukemia. In cohort C, all patients received ATG and an MA conditioning, regardless of age or underlying malignancy. This explains differences donor types and intensity of conditioning between the cohorts (table 1). Other clinical characteristics were comparable. Two year OS (A=66.7%; B=58.7%; C=63.8%) and EFS (A=57.1%; B=52%; C=55.7%) was comparable between the cohorts. Two year CI of relapse was also comparable (A=30%; B=23%; C=28%). Two year NRM appeared higher in B, but this difference did not reach significance (A= 9.8%; B=24%; C=15%). The CI of aGVHD grade 2-4 and 3-4 at day 100 was significantly higher in T cell replete allo-SCT with MUD (2-4; A=23%; B=37%; C=20% (p=0.002); 3-4: A=5%; B=16%; C=4.7% (p=0.043)). The incidence of extensive cGVHD was significantly higher in T cell replete allo-SCT of MRD. (A= 25%; B=13%; C= 2.3% (p=< 0.001)). The low incidence of grade 3-4 aGVHD and extensive cGVHD without an increase in relapse or NRM, translated into a superior 2 year GRFS in patients receiving ATG combined with an αβTCR/CD19 allograft (C=55.6%) as compared to T cell replete allo-HSCT of MRD (A=38.1%) and MUD (B=40.8%) (Figure 1, p=0.04). This difference remained significant in a multivariate analysis. Conclusion We demonstrate that αβTCR/CD19 depletion combined with ATG, with a myeloablative conditioning and a very short course of immunosuppression results in very low incidences of life-threatening GVHD and an improved GRFS as compared to T cell replete allo-SCT for adult patients up to the age of 70. This is likely to positively impact the long term quality of life in survivors of allo-SCT[2]. In addition, this platform provides a window for additional early post allo-interventions to further improve the control of underlying hematological malignancies. 1. de Witte, M.A., et al., alphabeta T-cell graft depletion for allogeneic HSCT in adults with hematological malignancies. Blood Adv, 2021. 5(1): p. 240-249. 2. Oerlemans, S., et al. Relapse and severe Graft-versus-Host Disease have a negative impact on long-term symptoms and quality of life of patients three years after allogeneic haematopoietic stem cell transplantation. Annual meeting EBMT 2022.

Excellent Outcomes of HLA Matched Related Donor Transplant for Adults with Severe Sickle Cell Disease Using a Non-Myeloablative Conditioning with Thiotepa and Post-Transplant Cyclophosphamide: Multi-Center International Experience

Introduction: The validated curative treatment for sickle cell disease (SCD) is allogeneic hematopoietic stem-cell transplantation (HSCT). Despite paucity of available matched sibling donors (10-14%), they are preferred due to less immunogenic complications like graft versus host disease (GVHD) and graft failure (GF) using alternative donors. In-vivo T-cell depletion by post-transplant cyclophosphamide (PTCy) has been shown to be most effective in GVHD control and a non-myeloablative regimen minimizes the toxicity associated with HSCT in this vulnerable population. In 2013, the multi-institutional Vanderbilt Haploidentical Learning Collaborative showed the improved outcomes of their non-myeloablative regimen for related haploidentical BMT for SCD (ClinicalTrials.gov identifier NCT01850108). We used a similar non-myeloablative approach to improve donor engraftment rates, while minimizing GVHD. Material and methods: This study was conducted at three international centers using similar conditioning from our experience in multi-institutional Vanderbilt Global Haploidentical Learning Collaborative to optimize haploBMT for SCD. The conditioning regimen included ( Figure3): rabbit anti-thymoglobulin (ATG) 4.5 mg/kg, thiotepa 10 mg/kg, fludarabine 150 mg/m2, cyclophosphamide 29 mg/kg and total body irradiation (TBI) 200 cGy. GVHD prophylaxis included PTCy 100 mg/kg, mycophenolate mofetil (MMF), and sirolimus. Stem cell source included bone marrow (BM) mobilized with filgrastim (5-10 μg/kg/d x 3-5 days) and peripheral blood (PB). Primary graft failure (GF) was defined as <5% donor myeloid/lymphoid chimerism or <5% donor cells by whole blood (WB) chimerism by day+28 posttransplant. Secondary graft rejection was defined <5% donor myeloid/lymphoid chimerism or <5% donor cells by whole blood (WB) chimerism with prior documentation of >5% donor cells by day +28. The Event free survival (EFS) was defined by survival with no GF, no death and/or no chronic GVHD. This cohort includes 4/22 patients (18.2%) had prior graft failure from a previous bone marrow transplants. Results: Here we report the outcome of 22 SCD patients (100% HbSS genotype), with a median age of 26.5 (15-41), transplanted from 10/10 MRD 86.4 % (n= 19) or single antigen mismatch related donor (MMRD) (9/10) 13.6% (n=3). The stem cell source was PB in 54.5% (12/22), and BM in 45.5% (10/22). Median CD34 stem cells dose was 6 X 10 6/Kg (1.2 - 10.25). Neutrophils and platelets engrafted at a median of 21.0 (15 - 26) and 25.0 (12 - 45) days, respectively. Demographic and clinical characteristics of participants summarized in Table 1. No primary or secondary graft failure was observed in the participants based on the last follow-up and time of analysis of this report. For participants with durable engraftment, the median WB chimerism values for D+28 and D+365 engraftment was 99.25% (n=14; IQR: 52 - 100) and 96.5% (n=16; IQR: 52 - 100), respectively. The median follow-up time was 14.6 months (n=22; IQR: 0.5-45.44). The overall incidence of acute GVHD grade III-IV was 4.5% (n= 1/22), and no incidence of chronic GVHD. There was no transplant related mortality. A Kaplan-Meier based probability of overall survival (OS) was 100%, Figure 1. All patients were off immunosuppression at 1-year post transplant. EFS as defined in the method was 100%, Figure 2. The EFS of free acute GVHD grade III-IV was 95.5%. Conclusion: This result shows the superiority of Thiotepa based non-myeloablative conditioning and PTCy for MRD transplants in adults with severe SCD. It not only minimizes the toxicity and GVHD but provides optimal donor engraftment mitigating against risk of secondary myeloid neoplasms from mixed chimerism. This needs further validation in a larger cohort.

Differences between Peripheral and Bone Marrow Lipidomics in Patients with Severe Aplastic Anemia and Its Finding in Predicting the Early Immunosuppressive Therapy Response

Aplastic anemia (AA) is a common clinical hematological disease, which is characterized by pancytopenia due to bone marrow hematopoietic failure. AA can be divided into severe AA (SAA) and non-severe AA (NSAA) based on disease severity. Anti-thymoglobulin (ATG)-based immunosuppressive treatment (IST) is recommended as the main first-line treatment for AA patients when stem cell transplantation is not available. The mechanism of AA has not been fully clarified. When considering role of the bone marrow microenvironment, current studies showed that the abnormal of quantity, function, and differentiation of mesenchymal stem cells (MSCs) were involved in the occurrence and development of AA, including the boost of adipocyte. Han, et al. [PMID: 35445952] found that the peripheral serum lipid profile may have great meaning in the differentiation diagnosis between transfusion-dependent non-severe AA and hypo- myelodysplastic syndrome (MDS), as well as in predicting their response to cyclosporine (CsA). Our previous study [PMID: 36192750] also revealed that the higher apolipoprotein-A is a potential prognostic biomarker for severe AA patients treated with ATG-based IST. However, the understanding of peripheral serum lipid metabolism may not fully represent the changes in bone marrow. Herein, we try to investigate the difference of lipid metabolomic profile between bone marrow and peripheral serum in SAA patients, and explore its meaning in predicting early IST response. In this study, a total of 11 SAA patients and 15 age and sex matched healthy donors were enrolled. Among them, six SAA received ATG based IST (Table. 1). An orthogonal partial least-squares discrimination analysis (OPLS-DA) model was established to analyze the differences between the subgroups and overfitting was accessed by permutation test (Fig A, B). The following volcano map (Fig. C) and heat map (Fig. D) confirmed that there were differences in subgroups to a certain degree. To explain the difference, we firstly compared lipid metabolism profile between patients (P) and donors (D) in peripheral serum (ps) (P ps Vs D ps) and bone marrow (bm) serum (P bm Vs D bm), and found that the difference in bone marrow was more distinct than that in peripheral serum, which suggested bone marrow may be more reliable as clinical samples in studies (Fig. E). Secondly, bone marrow serum and peripheral serum (P bm Vs P ps) in SAA patients were compared, fatty acids were upregulated (Fig. F), which indicated that there may be hyperproduction or transport disorder of fatty acid in bone marrow than in peripheral serum. Thirdly, comparing patients' baseline bone marrow lipid metabolites with donors' bone marrow lipid metabolites and with patients' bone marrow after treatment respectively, and analyzing the intersections of differences in two comparison groups, there were 11 common different metabolites, including 4 sphingolipids, 2 glycerides, 2 glycerophospholipids, 2 glycolipids, and 1 steroid lipid. Pathway analysis illustrated those metabolites were involved mainly in metabolism of sphingolipid, glycerophospholipid and glycerophospholipid, indicating that IST may restore homeostasis of bone marrow by affecting those pathways. Finally, we compared the bone marrow serum lipidomics between the SAA patients achieved 3-months response (CR/PR) and no response (NR). The difference of lipid metabolism was reduced after 3 months, while the differences in glucuronolipid (GlcADG) and phosphatidylinositol (PI) were significantly increased (Fig. G). In summary, difference of lipid metabolism between SAA and donors was more obvious in bone marrow, and the lipid metabolism process of bone marrow was less affected by external factors. IST may restore the homeostasis of lipid metabolism in the bone marrow by affecting metabolism of sphingolipid and glycerophospholipid, and GlcADG and PI may be used as new predictors for early IST response in SAA patients.

Safety and survival analysis of haplo-identical hematopoietic stem cell transplantation in patients with severe aplastic anemia who had previous failure to antithymoglobulin treatment

Objective: To investigate the safety and efficacy of haplo-identical hematopoietic stem cell transplantation (haplo-HSCT) conditioning with the same dosage form of antithymoglobulin (ATG) in patients with severe aplastic anemia (SAA) failure to ATG. Methods: This was a retrospective cohort study. A total of 65 patients with SAA who failed ATG treatment and received haplo-HSCT conditioning with the same dosage of ATG at the Institute of Hematology, Peking University People's Hospital between July 2008 and October 2020 were included as the ATG treatment failure group. An additional 65 SAA patients who applied ATG for the first time during haplo-HSCT were randomly selected by stratified sampling as the first-line haplo-HSCT group. Baseline clinical data and follow-up data of the two groups were collected. Conditioning-related toxicity within 10 days after ATG application and long-term prognosis were analyzed. The Kaplan-Meier was used to calculate the overall survival rate, and the Log-rank test was applied to compare the rates of the two groups. Results: In the ATG treatment failure group, there were 36 males and 29 females, and the age at the time of transplantation [M (Q1, Q3)] was 16 (8, 25) years. In the first-line haplo-HSCT group, there were 35 males and 30 females, with a median age of 17 (7, 26) years. Within 10 days of ATG application, the incidence of noninfectious fever, noninfectious diarrhea, and liver injury in the ATG treatment failure group was 78% (51 cases), 45% (29 cases), and 28% (18 cases), respectively, and in the first-line haplo-HSCT group was 74% (48 cases), 54% (35 cases), and 25% (16 cases), respectively; the difference between the two groups was not statistically significant for any of these three parameters (all P>0.05). For graft-versus-host disease (GVHD), there was no significant difference between the ATG treatment failure group and the first-line haplo-HSCT group in the development of 100 day Ⅱ to Ⅳ acute GVHD (29.51%±0.35% vs. 25.42%±0.33%), Ⅲ to Ⅳ acute GVHD (6.56%±0.10% vs. 6.78%±0.11%), and 3-year chronic GVHD (26.73%±0.36% vs. 21.15%±0.30%) (all P>0.05). Three-year overall survival (79.6%±5.1% vs. 84.6%±4.5%) and 3-year failure-free survival (79.6%±5.1% vs. 81.5%±4.8%) were also comparable between these two groups (both P>0.05). Conclusions: Compared with no exposure to ATG before HSCT, similar early adverse effects and comparable survival outcomes were achieved in patients with SAA who failed previous ATG treatment and received haplo-HSCT conditioning with the same dosage form of ATG. This might indicate that previous failure of ATG treatment does not significantly impact the efficacy and safety of salvaging haplo-HSCT in patients with SAA.

Whole-Exome Sequencing Identifies Fanc Heterozygous Germline Mutation As an Adverse Factor for Immunosuppressive Therapy in Chinese Aplastic Anemia Patients Aged 40 or Younger: A Single-Center Retrospective Study

Aplastic anemia (AA) is a bone marrow failure disorder characterized by pancytopenia. Currently, immunosuppressive therapy (IST) using cyclosporine (CsA) with or without anti-thymoglobulin (ATG) are the standard first-line management for AA patients not eligible for allogeneic stem cell transplantation. Several studies identified the influencing factors on IST response and survival, however, there are still a considerable number of patients suffering from poor prognosis even if they have achieved workable treatment, which encourage us to further identify additional prognosis / response predictor. The whole-exome sequencing (WES) is an accurate molecular technique to rule out congenital hematopoietic failures in young patients with pancytopenia. Up to date, several reports showed a relatively higher FANC heterozygous germline mutation rate was found in AA/MDS patients than general population, which may contribute to hematopoietic failure and confer congenital susceptibility to myeloid malignancies. Mostly, immunosuppressive therapy (IST) rescues hematopoiesis stem cell from cytotoxic T lymphocyte mediated bone marrow failure, but may exert limited effect in reconstruct gene deficit induced hematopoietic dysfunction. At present, few study focus on exploring the impact of FANC mutation on the response of AA to IST treatment, as well as its long-term prognosis. Herein, we respectively reviewed the AA patients who have the WES result in our cohort. A total of 61 patients aged ≤40 years old diagnosed with AA and underwent WES analysis were enrolled in this study, and result showed unexpected high FANC heterozygous germline mutations in our cohort (28/61, 45.9%) (Fig. A). Patients with FANC mutations have a significantly lower absolute reticulocyte count, and CD34+ % in bone marrow, and also lower 3, 6, and 9-month IST response than that without mutation, which were 0% vs. 25% (P=0.017), 26.3% vs. 42.1% (P=0.495), and 29.4% vs. 72.2% (P=0.011), especially in anti-thymocyte globulin combined with Cyclosporin A (ATG + CsA) group, which were 0% vs.33.4% (P=0.143), 25% vs.83.3% (P=0.103), and 25% vs. 100% (P=0.003), respectively (Fig. B-E). While the efficiencies of patients received HSCT were all 100% at 3rd, 6th, and 9th months evaluation. The overall survival (OS) didn't have a difference based on FANC status as well as treatment strategy (IST vs. HSCT), only one patient in the FANCmut group transformed into acute myeloid leukemia (AML) 49 months after the failure of CsA single treatment and died due to severe infection (Fig F, G). The event-free survival (EFS) in the FANCwt group was better than that in the FANCmut group (P=0.016) (Fig H), and also showed in patients received ATG + CsA treatment (P=0.045) (Fig I). We further explored the possible factors that may affect the EFS, and the FANC mutation was found to be the only predictor associated with poorer EFS [odds ratio (OR)=5.576, 95% confidence interval (CI): 1.169-26.590, P=0.031] in patients received IST (Fig J). In summary, WES based detection of FANC heterozygous germline mutations may have a great meaning in predicting IST response of acquired AA. For patients younger than 40-year-old without FANC germline mutation, ATG + CsA can exert a curative effect that was comparable to HSCT, while for cases with FANC mutation, HSCT may be a better choice. FANC germline mutation can negatively impact the IST response for Chinese patients with AA. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Allogeneic Hematopoietic Cell Transplant Yields Long Term Disease Free Survival in a Significant Number of Patients with Classic Hodgkin Lymphoma

Background: Classic Hodgkin's lymphoma (cHL) is a highly curable disease. A minority of patients, however, will have relapse/refractory (RR) disease and these patients are challenging to manage especially those who relapse after autologous hematopoietic cell transplant (auto-HCT). Even though a number of salvage options are available for these patients none of them is considered curative except allogeneic hematopoietic cell transplant (allo-HCT). Design and Methods: Retrospective analysis of 33 patients who had allo-HCT using matched family donors for cHL between January 2007 and December 2021. Continuous variables were summarized using medians and ranges. Categorical variables were summarized using frequencies and percentages. Probabilities of overall survival (OS) and disease free survival (DFS) were calculated using Kaplan-Meier estimate. Statistical analysis was conducted sing R studio (version 1.3.959 © 2009-2020 RStudio, PBC). Results: The median patient age at allo-HCT was 27 years. Seventeen patients were males and 16 were females. Five patients had early stage disease (Ann Arbor stage I, II) and 28 had advanced stage disease (Ann Arbor III, IV). Regarding the histologic type of cHL, eighteen had nodular sclerosis (NS), eight had mixed cellularity (MC), one had lymphocyte rich (LR), one had lymphocyte depleted (LD) and five cases were labeled as classic HL without further classification. Seventeen patients received brentuximab vedotin and fourteen patients received check point inhibitors prior to allo-HCT. The median number of chemotherapy lines prior to allo-HCT was 4 (range: 2-8). Twenty seven patients had chemosensitive disease (complete or partial remission) while 6 patients had chemoresistant disease (stable or progressive) prior to allo-HCT. Twenty seven patients had undergone auto-HCT prior to allo-HCT. Eighteen patients had elevated (>50) erythrocyte sedimentation rate (ESR) while 15 had normal ESR prior to allo-HCT. The majority of patients were conditioned with a reduced intensity regimen (29 patients versus 4 patients conditioned with myeloablative regimen). Twenty five patients received non-TBI (total body irradiation) based conditioning while 8 patients had TBI based regimen. The most frequently used conditioning regimen was fludarabine + melphalan. Nine patients received ATG (anti thymoglobulin) as a part of the conditioning while 24 patients did not. Thirty one patients received peripheral blood graft while 2 patients received bone marrow graft. The five years DFS was 37.5%. Twenty seven % of patients had acute GVHD (graft versus host disease) and 48% had chronic GVHD. The effect of a number of variables (number of chemotherapy lines, pre-allo-HCT ESR, conditioning intensity, ATG vs no ATG, receipt of pre-allo-HCT brentuximab or check point inhibitors, prior auto-HCT, chemosensitivity pre-allo-HCT and histologic subtype) was tested on the DFS. The only two variable that were statistically associated with a better DFS were pre-allo-HCT chemosensitivity (P=0.006) and non-NS histologic subtype (P=0.027). (Figure 1 and 2). Conclusions: Allogeneic stem cell transplantation can result in long-term progression-free survival in heavily pre-treated patients with Hodgkin's lymphoma. Patients with no response to salvage chemotherapy pre-allo-HCT and patients with NS subtype had detrimental outcomes. Better selection of patients before allo-HCT can result in a higher cure rates. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Apolipoprotein-a Is a Potential Prognosis Biomarker for Severe Aplastic Anemia Patients Treated with ATG-Based Immunosuppressive Therapy: A Single-Center Retrospective Study

Aplastic anemia (AA) is a bone marrow failure disorder characterized by pancytopenia with a risk of hemorrhage and infection. AA can be further divided into severe AA (SAA) and non-severe AA (NSAA) based on the severity of the disease. Anti-thymoglobulin (ATG)-based immunosuppressive therapy (IST) is the standard first-line management for SAA and very severe AA (VSAA) patients not eligible for hematopoietic stem cell transplantation (HSCT). Several studies identified the influencing factors on response and survival, including patient age, disease severity, absolute reticulocyte count and the interval between diagnosis and treatment. However, the prognosis cannot be improved if the patient exhibits poor response indicators when ATG-based IST is the only appropriate method. Adipocytes occupy the bone marrow of SAA, but the function of these cells is not yet clarified. Herein, we conducted this study aimed to explore the serum lipid changes during the ATG-based IST and identify the putative indicators that may predict the prognosis, thereby implying them as potential therapeutic target. A total of 61 newly diagnosed SAA/VSAA patients aged between 10 and 60 years who received ATG-based IST were enrolled, and divided into IST-response (IST-R, n=40) and IST-non-response (IST-NR, n=21) groups based on the 9-month response effect. Differences were observed in blood lipids level, immunoglobulins and complements among groups after ATG-based IST. Significantly higher serum total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), apolipoprotein A (Apo-A) levels were detected in the IST-NR group than the IST-R group pretreatment (all P<0.05). After ATG-treatment, the Apo-A levels increased in the IST-R group while decreased drastically in the IST-NR group (Fig. A-F). Both groups showed decreased IgA after 3 months after IST, and the level in the IST-R group was much lower than that in the IST-NR group (P<0.05) (Fig. G-K). In order to predict the 9-month response early, we conducted a correlation analysis and found that the 9-month IST response had a moderate negative correlation with IgA level at 3 months (Spearman's r=-0.516, P=0.006) and a negative correlation to pretreatment Apo-A (Spearman's r=-0.380, P=0.004). Considering the dramatic changes between the IST-R and IST-NR groups, enrolled patients were respectively divided into two subgroup based on the cutoff value of Apo-A and IgA by receiver operating characteristic (ROC), and found that patients with lower Apo-A (<1.205 g/L) level pretreatment had a better event-free survival (EFS) (P=0.008)，but no differences were observed on OS (Fig. L-M). The patients with IgA level ≥1.72 g/L showed poorer EFS compared to those with IgA <1.72 g/L, although no statistically significant difference was noted (Fig. N-O). In conclusion, the current study found that serum Apo-A is a potential prognosis biomarker for the newly diagnosed <60-year-old SAA/VSAA patients who received ATG-based IST, and the level of 3-month IgA can also be an indicator for 9-month IST response. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Effect of regulatory T cells on short-term graft outcome in kidney transplant recipients, a prospective observational, single-center study

BackgroundRegulatory T cells (Tregs) are important for maintaining immune homeostasis, limiting kidney transplant rejection, and promoting transplant tolerance. Tregs are characterized as CD4 + CD25+ T cells and the transcription factor Foxp3; they constitute 5–10% of all peripheral CD4+ T cells in healthy humans. The reduction in Treg cells after transplantation may be a predictive factor in graft rejection. Therefore, in this study, we investigated the association between Tregs and short-term graft outcomes in renal transplant recipients. MethodsThis prospective observational study included 50 patients of both sexes, aged between 18 and 60 years, with end-stage renal disease (ESRD), and who underwent kidney transplantation at the Nizams Institute of Medical Sciences. Flow cytometry was used to measure the percentage of Tregs (CD4 + CD25+) pre-transplant (baseline) and monthly post-transplant in 50 transplant recipients and 20 healthy controls (HC) over six months. The correlation between Treg percentages and graft outcomes was analyzed. ResultsThe percentage of Tregs (Treg%) was significantly lower in ESRD patients before transplantation (baseline) than in the HCs [median 8.5% vs. 14.25%; p < 0.01]. After transplantation, Treg% decreased significantly within a week after grafting compared to the baseline pre-transplant level [median 5.13% vs. 8.5%; p < 0.01]. Moreover, Treg% was lower in the older (> 40 years) than that in the younger age group at one week after transplantation (p > 0.001). Treg% (CD4 + CD25+) was significantly lower in patients with deceased donor renal transplantation (DDRT) than in live renal transplantation (LRT) within the first week of transplantation [median 2.16% vs. 4.6%; p < 0.05] and at the time of graft rejection [median 3.2% vs. 9.2%; p < 0.001]. Induction therapy with anti-IL-2 receptor monoclonal antibody (IL-2RB) lowered Tregs to a greater extent than anti-thymoglobulin (ATG) therapy and no induction therapy [median 3.22% vs. 5.47%, 8.4%, p < 0.05]. In contrast, an increased Treg% was observed in transplant recipients with normal kidney graft function within six months after transplantation compared with the pre-transplant baseline level [median 11.54% vs. 8.5; p < 0.001]. ROC analysis of graft rejection resulted in an area under the curve (AUC) of 0.8 with a p-value <0.05. ConclusionWithin the first week after transplantation, the percentage of pre-transplant Tregs was significantly decreased compared to that in age- and sex-matched HC. The percentage of Tregs was also lower in patients with advanced age, DDRT, and those who received IL-2RB induction therapy. Patients who experienced graft rejection had lower Treg% compared to their pre-transplant levels. In contrast, patients with normal graft function at six months showed increased Treg%. Together, these results suggest that Treg% measurements are correlated with clinical outcomes.

Interleukin - 2 Receptor Antagonists Induction Therapy in Simultaneous Heart - Kidney Transplantation

<h3>Purpose</h3> SRTR data currently suggests that induction therapy in simultaneous heart-kidney transplantation (SHKT) with rabbit antithymoglobulin (ATG) provides survival advantage compared to interleukin-2 receptor antagonist (IL2-RA). We are reporting the outcomes of recipients with SHKT treated with IL2-RA as induction therapy. <h3>Methods</h3> This is a single center, retrospective study of 26 patients who received SHKT at our institution from Dec 2018 to Oct 2021. A multidisciplinary team composed of heart and kidney transplant medical and surgical members determined appropriate recipient-donor SHKT candidate pairs. The majority of patients received IL2-RA induction therapy, and all patients received triple immunosuppression therapy with prednisone, mycophenolate mofetil and tacrolimus. Adjustments in long term therapy were made in collaboration between the heart and kidney transplant teams. <h3>Results</h3> From Dec 2018 to Oct 2021, 26 patients underwent SHKT. 23 patients (88%) were male, the median age was 57 years, and 5.4% were ≥ 65 years. 18 patients (69%) had non ischemic cardiomyopathy and 24 patients (92%) had CKD (mean GFR ≤ 35%). 18 patients were listed Status 2 and 2 patient Status 5. One patient received a DCD donor and 12 patients (46%) received hep C donors. 25 patients (96%) received induction therapy with IL2-RA. During the first 3 months post-transplant, the only patient who received ATG had 7 severe infections; 11 patients (44%) and 13 patients (52%) who received IL2 -RA had no infections and ≤ 4 mild infections, respectively. One patient died due to COVID 19 pneumonia complicated by multisystem organ failure. For a median follow up period of 410 (187-707) days, 8% patients in the IL2-RA induction cohort experienced a 2R/3A heart rejection, 8% patients remained on HD due to primary kidney graft non-function, and the survival rate was 96%. <h3>Conclusion</h3> Compared with present literature, our data support the use of IL2- RA as an induction strategy in SHKT with excellent patient survival.

Early Immune Reconstitution after Hematopoietic Stem Cell Transplantation for Adolescents and Adults with Sickle Cell Disease

IntroductionAllogeneic hematopoïetic stem cell transplantation (HSCT) is the only established curative therapy for patients (pts) with sickle cell disease (SCD). It is mostly performed in children 1, due to higher risk of graft-versus-host disease (GVHD) and transplant related mortality in adults. Different approaches have been developped to improve tolerance of transplant in adults: use of reduced intensity conditioning (RIC) regimens 2 and intensive immunosuppression to avoid GVHD. Here, we have studied the impact of such approaches on immune reconstitution in adolescents and adults transplanted for SCD.Patients and methodsWe report 39 transplants in adolescents and adults, performed in Saint Louis hospital from 2008 to 2020: 25 were matched related transplants (MRT) and 14 haplo-identical related transplant (HRT). In MRT, conditioning was myeloablative (MAC) in 15 pts (busulfan, cyclophosphamide, rabbit anti-thymoglobulin (ATG) 20 mg/kg) and non myeloablative (NMA) in 10 pts (alemtuzumab 1 mg/kg, 3 Gy total body irradiation (TBI)). In MAC transplants, stem cell source was bone marrow and post-transplant immunosuppression was methotrexate and cyclosporine. In NMA transplants, stem cell source was peripheral blood cells with post-transplant immunosuppression by sirolimus. In the 14 HRT, the conditioning was reduced (cyclophosphamide, thiotepa, fludarabine, 2 Gy TBI, ATG 4.5 mg/kg), stem cell source was bone marrow and GVHD prophylaxis was ensured by post-transplant cyclophosphamide (100 mg/kg), sirolimus and mycophenolate mofetil.ResultsMedian age at transplant was 17 years (y) old (range (r) 14-39). With a median follow-up of 3.6 y, the 2-y overall survival and survival without SCD were 97% (IC95%: 0.92-1) and 92% (IC95%: 0.83-1) respectively: no event after MRT, 1 death of GVHD and 2 graft rejections after HRT. The acute GVHD grade II-IV rate was 33%: 21% after HRT, 13% after MAC MRT and 0% after NMA MRT. Chronic GVHD occured in 3 pts (8%): severe in 1 HRT and mild in 2 MAC MRT. At 6 months, the blood chimerism evaluated in the 36 patients alive without rejection, was more often mixed (5 to 95% of donor) after NMA MRT (100%) versus MAC MRT (40%, p = 0.003) and HRT (18%, p < 0.001).Total lymphocytes (TL) counts increased rapidly in HRT and MAC MRT with a normalization from 3 months post-transplant. In contrast, NMA MRT experienced a slower recovery: at 6 months, median count was 1039/mm3 (r 463-1767) compared to 2071/mm3 (r 882-5985, p = 0.002) after MAC MRT and 2382/mm3 (r 676-3978, p = 0.005) after HRT. After NMA MRT, TL counts remained lower than normal values up to 12 months with a median of 1195/mm3 (r 870-3210) (Figure 1A).HRT displayed a rapid normalization of CD4 counts with a 3-month median count of 645/mm3 (r 350-1076) higher than reported after MRT (p < 0.001). Evolution of CD4 counts was similar after NMA and MAC MRT. They were lower than normal values during the first 12 months: median 364/mm3 and 388/mm3 respectively at 12 months (p = 0.25) (Figure 1B).From 3 months post-transplant, CD8 counts reached normal values after MAC MRT (314/mm3, r 108-2175) and were superior to normal after HRT (1335/mm3, r 66-4529), with a significant difference between HRT and MRT (p = 0.003). After NMA MRT, there was a trend for lower 3-month CD8 counts compared to MAC MRT: median of 107/mm3 (r 18-631, p = 0.08). CD8 counts remained under normal values after NMA MRT up to 12 months post-transplant (Figure 1C).From 3 to 6 months, CD4 and CD8 were mostly memory, with only 3.2% (r 0.1%-20.6%) and 6.2% (r 2.1%-11.2%) of CD45RA+ CCR7+ naïve CD8+ and CD4+ respectively.In the 3 groups NK cell counts reached normal values after 3 months.B lymphocytes counts normalized in the first months post-transplant except for patients who received rituximab for EBV reactivation. From 3 to 6 months, B lymphocytes were mostly naive: 98% of CD27- (r 92%-99%). Gammaglobuline levels were normal from 3 months in the 3 groups.Twelve (31%) pts were treated for a CMV and 6 (15%) for an EBV reactivation. No patient had CMV or adenovirus disease, or post-transplant lymphoproliferative disorder. Infections according to transplant types are detailed in figure 1D.ConclusionNMA MRT were associated with a delayed CD4 and CD8 recovery probably due to alemtuzumab. As previously reported 3, HRT displayed a rapid immune reconstitution. Despite use of serotherapy in the three modalities of transplant, the rate of viral infections remained acceptable without severe episode. [Display omitted] DisclosuresPondarré: ADDMEDICA: Honoraria. Peffault De Latour: Jazz Pharmaceuticals: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Amgen: Consultancy, Other, Research Funding; Alexion, AstraZeneca Rare Disease: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding. Boissel: CELGENE: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; JAZZ Pharma: Honoraria, Research Funding; Incyte: Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Servier: Consultancy, Honoraria; SANOFI: Honoraria; PFIZER: Consultancy, Honoraria.

A Prospective Phase 2 Study Testing High Dose Post-Transplant Cyclophosphamide As Sole Ghvd Prophylaxis after Matched Allotransplant Using Baltimore-Based Reduced-Intensity Conditioning Regimens and PBSC As Source of Graft

Introduction: The use of high-dose post-transplant cyclophosphamide (PTCY) has revolutionized graft-versus-host disease (GVHD) prophylaxis and allowed to successfully reconsider haplotransplant in recent years. As this strategy significantly reduces the incidence of both acute and chronic GVHD, PTCY has been thereafter considered not only in matched settings but also as sole GVHD prophylaxis, at least when considering myeloablative allotransplant using matched sibling (MSD) or unrelated (MUD) donors and bone marrow as source of graft. Here, PTCY, as a sole GVHD prophylaxis, was tested in a reduced-intensity conditioning (RIC) setting, using peripheral blood stem cells (PBSC) as source of graft considering that this platform is currently broadly used worldwide in adults.Methods: This prospective monocentric phase 2 study was designed with the main objective to demonstrate the feasibility and safety of using only PTCY (without cyclosporine A nor mycophenolate mofetyl after transplant) in adults (18-70 years old) eligible for a RIC PBSC transplant with MSD or MUD. The Baltimore platform with 2 days of PTCY 50mg/kg/day on days 3 and 4 post infusion was considered as conditioning regimen, using fludarabine for lymphoid disease or clofarabine for myeloid disease. The primary objective was to appreciate the incidence of corticosteroid-resistant acute grade 3-4 GVHD (CR 3-4 GVHD) within 100 days post-transplant. According to statistical rules, patients have to be included in a step by step fashion (3, 3, 6, 15, 15 and 17 patients) for a total of 59 evaluable patients (meaning having received PTCY), in order to stop the protocol soon enough in case of excessive rate of deleterious severe acute GVHD (graded according to Mount Sinai International Consortium). Thus, the trial had to be stopped in case of documentation of > 2 CR 3-4 GVHD for the first 3 patients, >3 CR 3-4 GVHD for the first 6 patients, > 4 CR 3-4 GVHD for the first 12 patients, > 6 3-4 CR GVHD for the first 27 patients, > 8 CR 3-4 GVHD for the first 42 patients and finally as soon as > 9 CR 3-4 GVHD for the last included patients. All patients gave informed consent. The trial was registered at ClinicalTrials.gov Identifier: NCT03263767.Results: The results of the first 27 first patients (males n=17 and female n=10; median age: 59 years old (yo), range: 26-70) are reported here. They were included between February 2018 and November 2020. Diagnoses were AML (N=8), MDS (N=5), CMML (N=2), myelofibrosis (N=5), CML (N=1), DLBCL (N=1), T-cell lymphoma (N=1), Philadelphia positive B-ALL (N=1), CLL (N=1), lymphoblastic lymphoma (N=1) and mixed phenotype acute leukemia (N=1). Donors were MSD in 10 cases and MUD in 17.Only one primary graft failure was documented in a 61 yo MDS patient with active disease at transplant. He is however still alive in response after autologous reconstitution. With a median follow-up of 17.6 months (range: 10-42) for alive patients at the time of analysis (July 2021), 1-year and 2-year survivals were 80.9+7% and 74.7+9%, respectively, for both OS et DFS. GVHD-free/relapse-free survival (GRFS) at 1-year and 2-year was 58.7+9% and 52.2+10%, respectively. Three relapses (11%) and 6 deaths occurred. Deaths were due to acute GVHD in 4 patients (including 1 with sepsis and 1 with SARS-COVID 19 infection) and relapse in 2. Grade 2, 3 and 4 acute GVHD occurred in 11, 1 and 4 patients, respectively, for a total of 59% of grade 2-4 acute GVHD. CR 3-4 GVHD was observed in all of 5 patients with acute grade 3-4 GVHD and 4 died related to GVHD. Moderate/severe chronic GVHD occurred in 5/22 (22.7%) evaluable patients, including 4 still on immunosuppressive therapy at 40, 28, 25 and 16 months post-transplant. Overall non-relapse mortality (NRM) was 14.8% and related to acute GVHD. However, the number of cases conducting to stop the protocol was not reached.Conclusion: PTCY as a sole GVHD prophylaxis is here demonstrated as possible and relatively safe for adults receiving a matched PBSC Baltimore-based RIC allograft. The very good survivals reported here may be related to a strong GVL effect associated with the high incidence of acute GVHD. However, because of this high incidence and the fact that NRM was related to GVHD after this first analysis, we have now made an amendment to test the addition to PTCY of one day of anti-thymoglobulin (ATG) 2.5 mg/kg on day-2 for the next 32 patients to be included. This second cohort receiving PTCY+ATG as a sole prophylaxis is ongoing. DisclosuresMoreau: Celgene BMS: Honoraria; Sanofi: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Oncopeptides: Honoraria.

Intravenous Once-Daily BuCy 2 With Pharmacokinetic (PK)-Guided Dose Adjustment As Conditioning Regimen For AML Patients In First Complete Remission

Introduction Busulfan (Bu) represents a backbone as conditioning prior to hematopoietic stem cell transplantation (HSCT). The intravenous (IV) form of Busulfan allows 100% bioavaibility and a limited inter- and intra-patient (pt) variability compared to the oral form. In Europe, IV Bu (Busilvex® fixed dose of 0.8 mg/kg x 16 doses) in combination with Cyclophosphamide (60 mg/kg/d x 2) is indicated prior to conventional HSCT in adults when the combination is the best available option. IV BuCy2 allows a precise delivery with 80% of adult pts within the defined therapeutic window [900 μmol/L x min-100 μmol/L x min] without dose-adjustments. Despite major advances in the risk-stratification and management of acute myelogenous leukaemia (AML) based on cytogenetics and molecular biology, the relapse rate remains high. Several published experiences suggested that Bu exposure may have an impact on the clinical outcomes after allogeneic HSCT. Study Objective The study was implemented to explore the use of a narrow range and high values of Bu exposure [4400 µmol/Lx min to 6000 µmol/Lx min] with a PK-guided dose adjustments and once-daily administration x 4 days. Methods The study was a prospective non-randomized multicentric phase II. The eligible pts were required to have AML in first complete (CR1, cytological remission) and to be eligible allogeneic HSCT following a myeloablative regimen. On the first day of the conditioning regimen IV Bu was administered as a single dose of 3.2 mg/kg; further daily dose of IV Bu were determined based on the previous Bu AUC exposure. The graft-versus-host disease (GVHD) prophylaxis consisted of calcineurin inhibitor, IV methotrexate post-transplant. The addition of antithymoglobulin (ATG) for unrelated donors was decided by each center based on their institutional guidelines. Pts could either receive related or unrelated bone marrow or peripheral blood stem cells. Nine centres with laboratory facilities for the pharmacokinetics analysis entered the study. Patient and transplant characteristics Thirty AML pts in CR1 (21 males, 70%) were treated between may 2010 and may 2012, 87% of pts had de novo AML. Twenty pts (67%) had matched sibling donor, the remaining pts received allograft from an unrelated donor. The median age of the cohort was 43.5 years [19.3-55.5]. The performance status score was comprised between 90 and 100. The majority of the cohort (83%) had an intermediate or unfavorable cytogenetic risk-factors. In 3 cases (10%) the karyotyping analyses could not be performed; 1 pt (3%) did not have cytogenetic test performed. Results Thirty pts were treated and analyzed. The expected cumulative AUC over 4 days [17600 µmol/Lxmin -24000 µmol/Lxmin] was reached in 90% of pts. The mean dose of IV Bu administered was 3.51 mg/kg/day. The mean total cumulative dose of IV Bu over 4 days was 13.25 mg/kg [8-21.3]. All pts engrafted. For the entire cohort, the neutrophil engraftment [absolute neutrophil count (ANC) > 0.5 x 10 9/L] occured at a median time of 17.5 d (11-35). Overall, 3 episodes (10%) of sinusoidal obstruction syndrome (S.O.S) occured (one mild, two severe, all resolved) in two patients. One pt developed 2 severe episodes of S.O.S and received defibrotide. Overall, 12 pts out of 30 (40%) developed acute GVHD between day 0 and day +100 after transplant (4 pts had grade III, 6 pts had grade II and 2 pts developed grade III, no patient developed grade IV). The median follow-up was 12 months [95% CI (11.9-12.2)] After day +100, 4 pts died of non-relapse causes ; one death from pulmonary fibrosis was related to the conditioning regimen. The cumulative incidence of TRM was 13.3% [95% CI (11.1%-15.6%)]. Five pts relapsed at a median time of 3.3 months [2-5.6] and 4 pts died of relapse. The cumulative incidence of one-year survival was 73.3% [95% CI (53.7%-85.7%)]. Conclusion The AUC intensification with once-daily IV BuCy2 is effective and yields an acceptable one year TRM for pts with high-risk AML in CR1. However, longer follow-up is needed in order to assess the impact of AUC intensification on the relapse rate and survivals. Disclosures: Suarez:Laboratoires Pierre Fabre: Travel grant Other. Off Label Use: IV Busulfan was administered in once-daily in this study. In Europe, IV Busulfan combined to cyclophosphamide is registered with a different schedule (infusion of IV Busulfan four times a day). IV Busulfan (Busilvex(r)) is an alkylating agent used as a conditioning regimen prior to hematopoietic stem cell transplantation. Socie:Laboratoires Pierre Fabre: Speakers Bureau. Michallet:Genzyme, MSD, BMS, Novartis, TEVA, Pfizer: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Paci:Laboratoires Pierre Fabre: Honoraria. Blaise:Laboratoires Pierre Fabre: Speakers Bureau, travel grant Other. Marcais:Laboratoires Pierre Fabre: travel grant Other. Xhaard:Laboratoires Pierre Fabre: Honoraria. Nicolini:BMS, Teva, Ariad, Pfizer, Novartis: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Furst:Laboratoires Pierre Fabre: travel grant Other. Levrault:Laboratoires Pierre Fabre: Employment. Riggi:Laboratoires Pierre Fabre: Employment. Ta Thanh Minh:Laboratoires Pierre Fabre: Employment.

Impact of In Vivo T-Cell Depletion in Patients with Myelodysplastic Syndromes Undergoing Allogeneic Hematopoietic Stem Cell Transplant: A Registry Study from the Chronic Malignancies Working Party of the EBMT

Background: in vivo T-cell depletion (TCD) is frequently used in the setting of allogeneic hematopoietic stem cell in order to decrease acute and chronic GVHD incidence. Several randomized studies, enrolling patients with myeloid disease have concluded to a decreased risk of GVHD without increasing the relapse risk. The present study included only myelodysplastic syndrome patients and evaluated the impact of anti-thymoglobulin (ATG) or alemtuzumab on outcomes.Method: these patients come from a Data Quality Initiative consisting in an improvement of the quality of the data asking centers to complete the missing data. 1284 patients transplanted in 14 centers between 2003 and 2014 have been included in this study. Median follow-up of the patients was 25 months. GRFS was defined as survival without relapse and without chronic extensive GVHD and no previous grade III-IV acute GVHD. Cytogenetics was defined according to classical IPSS and not calculated if patients were transformed into AML given 5 groups of patients: good, intermediate, poor, AML and missing (n=98). Multivariable models based on Cox proportional hazard were performed to test potential predictors and ATG effect was thus included in the models. Statistical analysis was performed using R software.Results: 814 patients received TCD and 470 did not. Characteristics of patients and transplant according to the TCD is given in the Table 1. Among patients who received a TCD, 168 received alemtuzumab while the other patients received ATG, either Grafalon® or Thymoglobuline®. At 6 months, cumulative incidences of acute grade II-IV GVHD and grade III-IV GVHD were 33% vs 31% and 13% vs 13% without or with TCD. At 5 years, chronic and extensive GVHD incidences were 64% vs 52% (Figure 1a. Chronic GVHD incidence) and 38% vs 25% without or with TCD. At 5 year, relapse incidence, relapse-free survival (RFS), OS and GRFS were 23% vs 28%, 42% vs 39%, 47% vs 43%, and 21% vs 26% without or with TCD (Figure 1b: OS, Figure 1c: GRFS).In the multivariable models for OS, adjusted on age (HR: 1.01, p<0.001), Karnofsky score (HR: 0.99; p<0.0001), disease classification (MDS without blast excess, HR: 0.7, p=0.004), disease status (noCR, HR: 1.3, p=0.002), platelet count at time of transplant (HR: 0.46/1 Giga, p=0.03), type of donor (unrelated, HR=0.99, p=0.94) and cytogenetics (intermediate, HR=1.01, p=0.92; poor, HR=1.5, p=0.004; AML, HR=1.3, p=0.01; unknown, HR=1.1, p=0.44), TCD had no significant impact (HR: 1.1, p=0.12).In the multivariable models for GRFS, adjusted on age (HR: 1.01; p=0.003), Karnofsky score (HR: 0.99; p=0.0003), disease classification (MDS without blast excess, HR: 0.8, p=0.05), disease status (noCR, HR: 1.1, p=0.049), type of donor (unrelated, HR: 1.5, p=0.058) and cytogenetics (intermediate, HR=1.2, p=0.058; poor, HR=1.33, p=0.003; AML, HR=1.2, p=0.014; unknown, HR=1.2, p=0.21), TCD had a protective effect on GRFS (HR: 0.8, p=0.009).In the multivariable models for relapse risk adjusted on disease classification (MDS without blast excess, HR: 0.35, p<0.0001), cytogenetics (intermediate, HR: 1.6, p=0.03; poor, HR: 1.8, p=0.002; AML, HR: 1.7, p=0.003; unknown, HR=1.6, p=0.07) and type of donor (unrelated, HR: 0.7, p=0.002), TCD increased significantly the relapse risk (HR: 1.5, p=0.005).In the multivariable models for TRM adjusted on age (HR: 1.01, p=0.003), type of donor (unrelated, HR: 1.3, p=0.02), Karnofsky score (HR: 0.98, p<0.0001), platelet count at time of transplant (HR; 0.36/1 Giga, p=0.03), CMV serology (patient positive, HR: 1.3, p=0.005), TCD has no significant impact (HR: 0.99, p=0.97).Conclusion: TCD decreased the risk of chronic GVHD and increased the risk of relapse confirming the potential graft-versus-MDS effect. The reduction of chronic GVHD do not translate into a decreased TRM and do not impact OS in patients who did not receive TCD while GRFS tended to be better in patients who received TCD. This study shows in a specific cohort of MDS with a relative long follow-up that TCD has major impact on outcome. [Display omitted] DisclosuresForcade:Neovii: Other: Travel grant. Socié:Alexion Pharmaceuticals, Inc.: Consultancy.

Immune Reconstitution after Allogeneic Stem Cell Transplantation - a Systematic Single Center Survey

The renewal of the immune system after allogeneic hematopoietic stem cell transplantation (HSCT) is a complex process not fully understood. Recently, the use of reduced intensity conditioning (RIC) regimens, new anti-viral drugs and intensified GvHD treatment changed the landscape of allogeneic transplantation. Here, the influence of several parameters on the development of the cellular and humoral immunity of 136 patients consecutively transplanted in a single center was analyzed.All adult patients transplanted during a period of three years (September 2010 to August 2013), were analyzed in respect of immunoglobulin levels with the turbidimetric method, serum electrophoresis, immunofixation and lymphocyte subset counts by flow cytometry. Also the occurrence of a monoclonal/biclonal gammopathy was reported. In addition, we looked for donor chimerism, B and T cell receptor repertoire of peripheral blood samples. Most patients received a reduced conditioning regimen; nearly all patients received either anti-thymoglobulin (ATG) or alemtuzumab (25/136 matched related donors) leading to a relatively low rate of chronic GvHD (40%). The immune parameters obtained one year after stem cell transplantation were correlated with relevant factors of stem cell transplantation, namely the conditioning regimen, diagnosis, relapse rate, age, sex and history of CMV infection, acute and chronic GvHD using Pearson correlation, t-test and regression analysis (SPSS).A normal CD4/CD8 ratio at day 360 after HSCT was only seen in 14% of evaluable patients, while it was reduced in 83%. This was mainly due by an impaired CD4 cell count while the CD8 cell count was even increased in 42%. The CD8 cell count was significantly higher in patients after CMV infection (p<0.001) and in those not receiving alemtuzumab as part of the conditioning regimen (p=0.003). The IgG level was normal in 51%, reduced in 31% and increased in 17 % of tested patients. The IgG level correlated with a history of CMV infection, NK, CD4, and CD8 cell count (all p≤0.025); but age, sex, diagnosis, relapse, use of RIC, acute and chronic GvHD had no significant impact. The development of a new clonal gammopathy was found in 18 patients after undergoing a HSCT and was in nearly all cases reversible. Interestingly, this was associated with chronic GvHD (p=0.034), but not any of the other parameters.Almost all patients show a compromised immune system one year after allogeneic stem cell transplantation mainly characterized by an inverted CD4/CD8 ratio. Whether an increased CD8 cell count may not only reflect the response to viral infections but in some cases improved immunosurveillance, is hard to document. Interestingly, the immunoglobulin levels are highly variable ranging from antibody deficiency to hypergammaglobulinemia positively correlating with CMV reactivation. Continuous disbalanced immunoreactivity indicated by clonal gammopathy was associated with chronic GvHD. The systematic evaluation of these basic immune parameters may lead to better therapeutic guidance in patients after allogeneic HSCT. DisclosuresNo relevant conflicts of interest to declare.

Induction and Increased Risk of Infections in Pediatric Fontan Patients after Heart Transplantation

<h3>Purpose</h3> To understand whether patients who have undergone Fontan palliation may have a higher susceptibility to post-HT infections given thymectomy in infancy and known depletions of T-cell subsets. <h3>Methods</h3> This was a single-center, retrospective cohort analysis of pediatric patients undergoing HT for dilated cardiomyopathy (DCM) or Fontan failure, who underwent induction with anti-thymoglobulin (ATG). The primary endpoint was infection in the first 180 days post-HT, defined as (1) positive blood/urine/respiratory culture; (2) positive viral PCR (excluding CMV and EBV); (3) skin or wound infection; and/or (4) culture-negative infection if a full antibiotic course (>5 days) was completed. Secondary endpoints included (1) absolute lymphocyte (ALC) and CD3 counts after 3 and 5 doses of anti-thymocyte gammaglobulin (ATG); (2) the incidence of post-transplant lymphoproliferative disorder (PTLD); and (3) rejection (≥ Grade 2R ACR or pAMR2) in the first 180 days post-HT. <h3>Results</h3> From 2014 to 2019, 59 pts (26 Fontan, 33 DCM) underwent HT at a median age of 14.7 (IQR 10.6, 19.5) and 11.7 (IQR 1.4, 13.6) years, respectively. The median total ATG received was 7.4 (IQR 4.9, 7.7) vs 7.5 (IQR 7.3, 7.6) mg/kg (p=NS). The median CD3 [8 (IQR 5, 14) vs 16 (IQR 10, 39); p=0.01] after 3 doses of ATG and ALC [172 (IQR 98, 400) vs 427 (IQR 205, 824); p=0.014] after 5 doses of ATG was lower in Fontan vs DCM patients (<b>A,B</b>). Twenty-three patients (39%) developed ≥1 infection within 180 days post-HT, with a higher rate of infection in Fontan patients (54% vs 27%, p=0.03; <b>C, D</b>). Adjusted for pre-transplant ALC, the risk for infection within 30 days post-HT for Fontan patients was OR 7.62, 95% CI 1.13-51.48, p=0.037. There was no difference in the incidence of PTLD (12% vs 0%; p=0.08) or rejection (12% vs 21%; p=0.49) between Fontan vs DCM patients. <h3>Conclusion</h3> Compared to DCM patients, Fontan patients have lower CD3 and ALC after induction, as well as a higher risk of infection. Modifications to induction therapy for Fontan patients may be considered.

Post-transplantation Cyclophosphamide, Tacrolimus and Low-Dose ATG as GVHD Prophylaxis for Allogeneic Peripheral Stem Cell Transplantation for Adult Patients With Lymphoid Malignancies: A Single Arm Phase II Study.

The PT-Cy was considered as one of the mainstay protocol for graft verus host disease (GVHD) prophylaxis. Recent study demonstrated that PT-Cy combined with other immunosuppressants could further reduce the incidence of GVHD and improve the GVHD and relapse free survival (GRFS). In this prospective phase II study, we evaluated the effect of a new GVHD prophylaxis consist of PT-Cy combined with tacrolimus and low dose anti-thymoglobulin (ATG). A total of 23 patients were enrolled including 20 patients with acute lymphoblastic leukemia (ALL) and three patients with T cell lymphoma. The median age was 29 years (range, 16~58 years). Patients with HLA-matched related donor (MSD, n=7) received PT-Cy combined with tacrolimus, while patients with HLA matched unrelated (MUD, n = 2) or haplo-identical (Haplo, n = 14) donor received additional ATG at 2.5 mg/kg on day 15 or day 22 after engraftment of neutrophils. As to the acute GVHD (aGVHD), only three patients developed grade I (n = 1) or grade II (n = 2) aGVHD with 100-day incidence of all aGVHD and II-IV aGVHD at 13.0 ± 5.1% and 9.1 ± 6.1% respectively. Only two patients had mild and one had moderate chronic GVHD (cGVHD), with 1-year incidence of cGVHD and moderate/severe cGVHD at 15.2 ± 8.7% and 4.6 ± 4.4% respectively. A high incidence of CMV reactivation was documented (14/16 with MUD/Haplo donor and 2/7 with MSD) with only 1 CMV disease documented. There were two EBV reactivation without post-transplantation lymphoproliferative disease (PTLD) documented. With a median follow-up of 303 days (range, 75~700 days), three patients relapsed leading to 1-year cumulative incidence of relapse (CIR) at 12.8 ± 9.2%. Only one patient died of CMV pneumonia on day 91 with both 100-day and 1-year non-relapse mortality (NRM) at 4.6 ± 4.4%. The 1-year overall survival (OS), event-free survival (EFS) and GRFS were 95.5 ± 4.4%, 82.6 ± 9.5%, and 68.0 ± 11.3% respectively. Based on Simon's stage II design, our primary data showed that the PT-Cy+tacrolimus ± ATG protocol was promising in preventing aGVHD and cGVHD, which may translate into low NRM without increased CIR. Further clinical trial with large number of patients should be warranted. This trial was registered at www.clinicaltrials.gov as #NCT 04118075.

Pediatric Patients with Severe Aplastic Anemia Treated with Combined Immunosuppressive Therapy, Eltrombopag and Eculizumab and Their Clinical Course to Stem Cell Transplant

Acquired aplastic anemia (AA) in children is a rare disorder characterized by pancytopenia and hypocellular bone marrow. Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoetic stem cell (HCT) disorder characterized by complemented-mediated hemolysis, thrombosis and bone marrow failure secondary to deficiency of glycosylphosphatidylinositol-anchored proteins (GPI-AP) on hematopoetic stem cells. PNH and acquired AA are closely related; up to 50% of patients with AA have detectable PNH-clones at the time of diagnosis and small percentage of them can have clonal expansion throughout their disease course requiring close monitoring. Current standard therapy for severe aplastic anemia (SAA) patients without matched related donor (MRD) is immunosuppressive therapy (IST) regimen with anti-thymoglobulin (ATG), cyclosporine (CSA), and recent addition of eltrombopag. Eculizumab is a recombinant humanized monoclonal antibody that blocks complement protein C5 and prevents cell lysis. While it has been shown to be effective in children with PNH, concomitant treatment with IST for patients with SAA is unknown. To our knowledge, there has been no pediatric data on combined IST, eltrombopag and eculizumab treatment for children with AA with clinically significant PNH clones. Here we retrospectively reviewed three pediatric patients with SAA with PNH clones treated with IST, eltrombopag and eculizumab and their unique clinical courses. Two out of three patients had high PNH clone size and were started on eculizumab prior to IST with improvement in transfusion intervals. Of the two, one had decrease in PNH clone size after IST but the other patient's clone size continued to increase despite two courses of IST. Finally, the third patient had a minor PNH clone and was not started on eculizumab prior to IST. He remained asymptomatic for over a year until he developed symptomatic PNH with large clone size and aplastic bone marrow. His clone size continued to increase with no improvement in transfusion frequency despite being started on eculizumab. However, steroids were started based on anecdotal literature and his transfusion frequency decreased subsequently. All three patients are in the process of going through matched unrelated donor stem cell transplants. Several studies have reported the presence of a minor PNH clone at the time of AA diagnosis was associated a favorable response to IST. In this case series, the patient with the smallest PNH clone size at the time of diagnosis of SAA had the best response to IST compared to the other two patients who had larger PNH clone populations. These findings suggest that even though minor PNH population may lead to better response to IST compared to absence of the clone, the correlation between clone size and prognosis is unclear. Further study with larger sample size is needed to investigate this relationship. However, regardless of the population size, all three patients were able to prolong transfusion intervals using eculizumab without significant side effects. As the adoption of eltrombopag with standard IST is evolving with ongoing study, the efficacy of incorporating eculizumab to decrease transfusion frequency in patients with PNH-clone in addition to eltrombopag/IST regimen should be further investigated. Disclosures No relevant conflicts of interest to declare.

Heightened Immune Response and Increased Risk of Infections in Pediatric Fontan Patients after Heart Transplantation

Infectious complications are a major cause of morbidity & mortality after heart transplantation (HT). Patients who have undergone Fontan palliation may have a higher susceptibility to post HT infections given thymectomy in infancy and known depletions of T-cell subsets. This was a single-center, retrospective cohort analysis of pediatric patients undergoing HT for dilated cardiomyopathy (DCM) or failing Fontan physiology, who underwent post HT induction with anti-thymoglobulin (ATG). Repeat HTs and multi organ transplants were excluded. The primary endpoint was infection in the first 180 days post HT, defined as 1) positive blood, urine, or respiratory culture; 2) positive viral PCR (excluding CMV and EBV); 3) skin or wound infection; or 4) culture-negative infection if a full antibiotic course (≥ 5 days) was completed. Secondary endpoints included sensitivity to ATG as defined by 1) absolute lymphocyte (ALC) and CD3 counts after 5 doses; 2) the incidence of post transplant lymphoproliferative disorder (PTLD); and 3) rejection (>/= Grade 2R ACR or pAMR2) in the first 180 days post HT. From 1/2014 to 9/2019, 63 patients (30 Fontan, 33 DCM) underwent HT at a median of 15.4 (IQR 10.8, 20.1) and 11.7 (IQR 1.4, 13.6) years, respectively. The median total ATG received was 7.5 (IQR 6.7, 8.2) mg/kg vs 7.2 (IQR 4.7, 9.2) mg/kg (p=NS), respectively. The median CD3 [9 (IQR 3,14) vs 12 (IQR 6, 26); p=0.04, Figure 1A] and lymphocyte counts [172 (IQR 98, 354) vs 427 (IQR 205, 662); p=0.02] after ATG were lower in Fontan vs DCM patients. 28 patients (41%) developed at least one infection within 180 days after HT, with a higher rate of infection in Fontan patients (60% vs 24%, p=0.005; Figure 1B). There was no difference in the incidence of PTLD (10% vs 0%; p=0.1) or rejection (17% vs 27%; p=0.31) between Fontan vs DCM patients, respectively. Compared to DCM patients, Fontan patients have a more pronounced suppression of CD3 counts after induction, as well as a higher risk of infection.

Improved Gvhd Free, Relapse Free Survival Using Dual T-Cell Depletion with ATG and Ptcy in Matched Unrelated Donor RIC Allo-HSCT

Introduction The combination of anti-thymoglobulin (ATG), post-transplant cyclophosphamide (PTCy) and cyclosporine (CsA) provides an effective control of graft-versus host disease (GVHD) in allo-HSCT using peripheral blood stem cell (PBSC) grafts, as has been reported by Dr. Viswabandya et al. We aim to report a large, single center experience in reduced intensity conditioning (RIC) allo-HSCT using dual T-cell depletion with ATG and PTCy combined with CsA for GVHD prophylaxis using grafts from 10/10 matched unrelated donors. Patients and methods Between October 2015 and April 2019, 167 adult patients diagnosed with hematological malignancies underwent first 10/10 MUD RIC allo-HSCT. RIC regimen was composed by fludarabine, busulfan, and 200cGy of total body irradiation. For GVHD prophylaxis all recipients received rabbit-ATG, PTCy 50mg/m2/day on day +3 and +4, and CsA since day +5. One hundred sixteen (69.5%) recipients, transplanted between 2015 and May 2018, received a total dose of 4.5mg/kg of rabbit-ATG (given on day -3,-2 and -1). In May 2018, the dose of ATG was lowered to a total of 2mg/kg (given on day -3 and -2). A total of 51 (30.5%) recipients received the lowered dose of ATG. The median follow-up of the entire cohort was 14 months (range: 0.4-44.5). For those patients who got a higher dose of ATG was 20 months and for those who received a lower dose of ATG was 8.8 months. Data was collected retrospectively and updated on July 2019. Cumulative incidence (Cum.Inc) of GVHD analysis was assessed accounting relapse and death as competing events. Results Baseline and post-transplant information are summarized in the Table 1 and 2. Ninety-three (55.7%) recipients were diagnosed with acute myeloid leukemia (AML). The cum.Inc of grade II-IV and grade III-IV acute GVHD at day +100 was respectively 15.6% (95% confidence interval (CI) 10.6-21.6) and 3.6% (95% CI 1.5-7.3). The cum.Inc of acute GVHD was not significantly affected by the dose of ATG (P&gt;0.05). The cum.Inc of chronic GVHD was 10.9% (95% CI 6.6-16.4). Due to the shorter median follow up of the cohort that received a lower dose of ATG, the impact of the reduction of the dose in the cum.Inc of chronic GVHD was not explored. Overall, 48 (28.7%) recipients died and 35 (20.4%) relapsed. Main causes of death were relapse (14.4%) and infection (9.6%). Outcome information is reported in the Table 2 and Plot A, B and C. One-year overall survival (OS), relapse-free survival (RFS) and GVHD-free/RFS (GFRFS) were respectively 75.6%, 70.3%, 60.4%. Table 3 summarizes the impact of the use of a different dose of ATG in acute GVHD and post-transplant outcome. No significant differences were found between the two groups that receive a different dose of ATG. However, median follow-up was shorter in the cohort that received 2mg/kg of ATG. Table 4 reports the main post-allo-HSCT information of patients diagnosed with AML. One-year OS, RFS and GRFRS for this subgroup of patients were 76.8%, 71.9% and 65.9%. Conclusion The unique and modern combination of RIC PB allo-HSCT using ATG, PTCY and CsA for GVHD prophylaxis results in impressive post-transplant outcomes using 10/10 MUD. The use of dual T-cell depletion with ATG and PTCy is safe and provides an extraordinary control of GVHD with acceptable relapse rates using PB stem cell 10/10 MUD grafts. ATG of only 2mg/kg when it is combined with PTCy and CsA, results in an effective control of acute GVHD rates. The optimal dose of ATG for GVHD prophylaxis is not well established. Further investigations need to be done to determine the efficacy of a lower dose of ATG controlling chronic GVHD in this setting. For patients diagnosed with AML, this protocol is safe and an effective approach when a 10/10 MUD is available. Disclosures Michelis: CSL Behring: Other: Financial Support. Mattsson:Celgene: Honoraria; Gilead: Honoraria; Therakos: Honoraria.