aGVHD Grade Research Articles

The Impact of the Absolute Lymphocyte Count before Anti-T-Lymphocyte Globulin (ATLG) Administration on Transplant Outcomes in Matched Unrelated Peripheral Blood Stem Cell Allogeneic Stem Cell Transplantation

Background: Data on optimal ATLG dosing in MUD-PBSC-allo-SCT is limited. Conventional weight-based dosing may excessively deplete T-cells and lead to unfavorable outcomes. ALC-based dosing on ATLG administration day has been proposed as an alternative. We conducted a retrospective study at University Medical Center Hamburg-Eppendorf (UKE) and University Medical Center Bologna to investigate the impact of ALC and ATLG dose on transplant outcomes. Methods: We included 378 (UKE n=251, Bologna n=127) patients who underwent allo-SCT (years 2018-2023) with PBSCs from UD (97% HLA 10/10, 3% HLA 9/10) and received ATLG at a total dose of 30 mg/kg between days -4 and -1 in the UKE cohort and days -6 to -2 in the Bologna Cohort. Patients were categorized based on the median ALC 0.32Mrd/L (range 0-13.85) into the “low-ALC” group with (ALC ≤ 0.32Mrd/L) and the “high-ALC” group with measurable lymphocytes (ALC > 0.32Mrd/L) on the first day of ATLG administration, allowing for a comparison of transplant outcomes between these groups. Results: Median follow-up was 12 months (range 1-56). Median days to neutrophil engraftment was 11 (range 6-21) in the low-ALC group and 13 (range 8-27) in the high-ALC group (p<0.001). In univariate analysis, no significant differences in 2-year NRM were observed between low-ALC (16% [95%CI: 11-22%]) and high-ALC groups (12% [95%CI: 8-17%]; p=0.24), whereas allo-SCT year (≤ 2020: 18% vs >2020 10%, p=0.02), conditioning intensity (MAC 9% vs RIC 19%) p=0.005), disease status at transplant (CR: 10% vs not CR 18%, p=0.03) significantly affected NRM. In Multivariate analysis (MVA) only ALC (per 1 point increase HR 1.03 [95%CI: 1.0-1.1]; p=0.04) and conditioning intensity (RIC vs. MAC: HR 2 [95%CI: 1-3.8]; p=0.038) significantly impacted NRM. There was a trend for higher cumulative incidence of relapse (CIR) at 2 years in the low-ALC group (21% [95%CI: 16-27%]) when compared to the high-ALC group (16% [95%CI: 11-21%]), p=0.09. On UVA only Patient age (≤66 years 22% vs > 66 years 14%, p=0.02), TBI (No TBI 18% vs TBI 38%, p=0.003) affected CIR. On MVA only ALC (HR 0.98 [95%CI: 0.96-0.99]; p=0.013) TBI vs no TBI (HR 2.14 [95%CI: 1.3-3.5]; p=0.003) significantly affected CIR. A trend toward decreased 2-year OS was noted in patients with low-ALC (62%) compared to those with high-ALC (74%) p=0.06. On UVA disease status at transplant (CR: 74% vs not CR 61% p=0.004) conditioning intensity (MAC: 75% vs RIC: 62% p=0.01) and Immunosuppression significantly impacted OS. MVA revealed lower OS for non-CR patients (HR 2.68 [95%CI 1.6-4.49], p=0.024) and improved OS for MDS (HR 0.34 [95%CI 0.18-0.64]) and PMF (HR 0.04 [95%CI 0.01-0.35]), compared to AML and TAC+MMF led to reduced OS versus CSA+MMF (HR 5.99 [95%CI 1.91-18.82], p=0.002) PFS at 2 years was significantly lower in the low-ALC group (56%) compared to the high-ALC group (67%), p=0.038. Factors affecting PFS included ATLG dosing schedule (D-6 to -3: 70% vs D-4 to -1: 57% , p=0.02), patient age (≤66 years: 61% vs >66 years: 63%, p=0.04), disease status (CR: 68% vs not CR: 55%, p=0.005), and conditioning intensity (MAC: 67% vs RIC: 57%, p=0.048). MVA showed that females had higher PFS than males (HR 0.66 [95%CI: 0.45-0.97], p=0.037), non-CR status lower PFS (HR 2.51 [95%CI: 1.58-3.98], p<0.001), and MDS or PMF higher PFS over AML (HR 0.3 [95%CI: 0.17-0.55] and HR 0.08 [95%CI: 0.02-0.40], p<0.001, p=0.002). GRFS at 2 years was significantly lower in patients with low-ALC (31%) compared to those with high-ALC (48%) p=0.005). On UVA ATLG dosing-schedule (D-6 to -3: 52% vs D-4 to -1: 33%, p=0.001), donor CMV serology (negative: 47% vs positive: 33%, p=0.013), disease status (CR: 48% vs not CR: 28%, p=0.0002), and conditioning intensity (MAC: 44%vs RIC: 35%). Multivariate analysis showed non-CR status was associated with lower GRFS (HR 2.68 [95%CI: 1.6-4.49], p<0.001), transplantation for MDS (HR 0.34 [95%CI: 0.18-0.64], p<0.001) and PMF (HR 0.04 [95%CI: 0.01-0.35], p=0.003) higher GRFS compared to AML. We observed no significant differences in the cumulative incidence of aGVHD grade III-IV (8% in bopth groups, p=0.87) and cGVHD moderate/severe between the groups (at 2 years low-ALC 22% [95%CI 16-28] vs high-ALC 16% [95%CI 11-22] p=0.16). Conclusion: Higher ALC at ATLG administration may improve transplant outcomes after allo-SCT. These findings suggest tailoring ATLG doses based on ALC and earlier administration could optimize allo-SCT outcomes.

Outcomes of haploidentical transplants with PT-CY vs 10/10 MUD transplants with ATG in Germany

AbstractAllogeneic hematopoietic stem cell transplantation (allo-HSCT) is the best curative treatment modality for many malignant hematologic disorders. In the absence of a matched related donor, matched unrelated donors (MUDs) and haploidentical donors are the most important stem cell sources. In this registry-based retrospective study, we compared the outcomes of allo-HSCTs from 10/10 MUDs with antithymocyte globulin (ATG)–based regimens (n = 7050) vs haploidentical transplants (Haplo-Tx) using posttransplant cyclophosphamide (PT-CY Haplo; n = 487) in adult patients with hematologic malignancies between 2010 and 2020. Cox proportional hazard-and competing risks regression models were formed to compare the outcomes. Overall survival (OS), Disease-free survival (DFS), and graft-versus-host disease (GVHD)–free and relapse-free survival (GRFS) were superior for 10/10 MUDs (OS [hazard ratio (HR), 1.27; 95% confidence interval (CI), 1.10-1.47; P = .001]; DFS [HR, 1.17; CI, 1.02-1.34; P = .022]; GRFS [HR, 1.34; CI, 1.19-1.50; P < .001]). The risk of acute GVHD (aGVHD) grade 2 to 4, aGVHD grade 3 to 4, and chronic GVHD (cGVHD) was higher in the PT-CY Haplo group than the 10/10 MUD group (aGVHD grade 2-4 [HR, 1.46; CI, 1.25-1.71; P < .001]; aGVHD grade 3-4 [HR, 1.74; CI, 1.37- 2.20; P < .001]; cGVHD [HR, 1.30; CI, 1.11-1.51; P = .001]). A lower incidence of relapse was observed in the PT-CY Haplo group (relapse: HR, 0.83; CI, 0.69-0.99; P = .038). Unrelated 10/10 matched transplantation with ATG leads to lower GVHD rates and improved survival rates compared with PT-CY Haplo transplantation in Germany.

Antibiotic Prophylaxis During Allogeneic Stem Cell transplantation—A Comprehensive Single Center Retrospective Analysis

BackgroundProphylactic antibiotics are still controversial during allogeneic hematopoietic stem cell transplantation (allo-HSCT). In our transplant center, we suspended antibiotic prophylaxis during allo-HSCT in 2017. ObjectiveThe main objective of this study was the detailed analysis of the potentially beneficial impact of omittance of standard antibiotic prophylaxis during allo-HSCT in survival and Graft-versus-Host disease (GvHD) development, especially with consideration of confounding factors and competing events. Secondary objectives were the evaluation of the risk of severe infections and transplant-related mortality without antibiotic prophylaxis, the detailed assessment of bacterial and viral infections including multiresistant pathogens as well as occurrence of relapse in both groups. This study aims to support the development of future antibiotic strategies in allo-HSCT. Study DesignWe retrospectively analyzed patient outcome in the time periods before (between December 2012 and February 2017) and after suspension (between March 2017 and June 2020) of antibiotic prophylaxis during allo-HSCT. Relevant clinical outcome parameters of the patients (n = 221) were collected by chart-review in the two groups (with antibiotic prophylaxis n = 101 versus without antibiotic prophylaxis n = 120). All patients were 18 years or older. Propensity score methods were used to adjust for potentially confounding patient characteristics. To address competing events, transitions between moderate/severe acute and chronic GvHD, relapse and death were analyzed using an inverse-propensity score weighted multistate modeling approach. ResultsWhile we observed a trend towards an improved outcome in the cohort without antibiotic prophylaxis, the inverse-propensity-score-weighted analyses did not show significant differences between the two groups in overall survival (OS) (P = .811) or development of acute GvHD (aGvHD) grade 3/4 (P = .158) and chronic moderate/severe GvHD (cGvHD) (P = .686). Multistate analysis respecting competing events revealed comparable estimated probabilities without antibiotic prophylaxis versus with antibiotic prophylaxis in OS (35.0% [95% CI: 28.2%-42.7%] versus 35.3% [95% CI: 27.8%-41.1%]) as well as development of aGvHD grade 3/4 (7.7% [95% CI: 5.9%-12.2%] vs. 10.6% [95% CI: 7.7%-15.7%]) and moderate/severe cGvHD (21.0% [95% CI: 17.7%-30.0%] vs. 23.8% [95% CI: 19.6%-31.4%]). Similar analyses showed also no significant differences in relapse rate, transplant-related mortality, relapse-related mortality, or GvHD-free/relapse-free survival between the two groups. An observed increase in severe infections without antibiotic prophylaxis did not lead to a significantly higher mortality rate. Viral reactivation and detection of multiresistant bacteria were comparable, yet a higher incidence of Clostridioides difficile infections was observed in patients receiving antibiotic prophylaxis. ConclusionOur study supports previous reports of noninferiority of allo-HSCT without use of antibiotic prophylaxis with close monitoring and rapid intervention, if infection is suspected. The trend towards improved outcomes without antibiotic prophylaxis, however, might not only be due to the absence of antibiotic prophylaxis but also due to additional progresses in the field over the recent years. While the present study is too small to draw definite conclusions, these results strongly warrant further multicenter studies addressing the potential benefit of omitting antibiotic prophylaxis during allo-HSCT.

Anti-T-lymphocyte globulin (ATLG) compared to post-transplant cyclophosphamide as GvHD prophylaxis in ALL patients undergoing allogeneic stem cell transplantation

We retrospectively analyzed high-risk ALL patients in CR1 receiving total body irradiation based conditioning regimen with ATLG (n = 74) or PTCy (n = 73) for GVHD prophylaxis. The 3-year OS and LFS were similar in both groups: 65 and 60% in the ATLG group and 64 and 67% in the PTCy group (p = 0.9 and 0.5, respectively). CIR and NRM rate at three years was 12 and 21% after PTCy and 19 and 20% after ATLG (p = 0.4 and p = 0.9, respectively). Acute GvHD grades II-IV and grades III/IV at 100 days was 46 and 19% after PTCy and 33 and 10% after ATLG (p = 0.08 and p = 0.9, respectively). Chronic GvHD of all grade at two years was higher after PTCy: 55% versus 26% (p < 0.001). Based on the propensity score matching (PSM) analysis, aGvHD grades II-IV was trending higher in the PTCy group compared to the ATLG group (p = 0.07). In contrast to the PSM analysis, on multivariate analysis the receipt of PTCy compared with ATLG was associated with a reduced CIR (p = 0.026). Our retrospective single-center analysis shows a lower incidence of acute and chronic GvHD while displaying similar LFS and OS after ATLG compared to PTCy in TBI based allogeneic stem cell transplantation for high-risk ALL.

Real-World Challenges of Haplo-Identical Hematopoietic Stem Cell Transplant in a Developing Country: A Single Center Experience.

Hematopoietic stem cell transplant (HSCT) is potentially, the sole curative option for many malignant and non-malignant hematological disorders. Finding a human leukocyte antigen (HLA) compatible donor remains one of the limiting factors, hampering the utilization of HSCT. However, the introduction of post-transplant cyclophosphamide (PTCy) has improved the outcomes of haploidentical transplants making it a suitable option for patients lacking HLA-compatible donors. We collected data from 44 patients who underwent haplo-identical allogeneic stem cell transplants at the Armed Forces Bone Marrow Transplant Center/National Institute of Blood and Marrow Transplant (AFBMTC/NIBMT) from the year 2015 to 2022. The diseases were divided into three categories, i.e., bone marrow failure (BMF) syndromes, hematological malignancies (HM) and miscellaneous (Misc) groups. Median age at transplant was 18 (01-39) years. Transplant indications included aplastic anemia (AA) in 21 (47.7%) cases, 15 (34.1%) HM, and eight (18.2%) cases falling in the Misc groups. A maximum number of graft failures occurred in the BMF group; primary graft failure in 07 (33.3%) cases and secondary graft failure in four (19%) cases, (p-value < 0.05). Acute graft versus host disease (aGVHD) grade II-IV occurred in nine (20.5%) cases while chronic graft versus host disease (cGVHD) occurred in 10 (22.7%) cases. Cytomegalovirus (CMV) reactivation was seen in 31 (70.5%) cases. Maximum CMV reactivation was seen in HM group 13 (86.6%) cases, (p-value < 0.05) as compared to BMF (71.4%) and Misc groups (37.5%). Post-transplant cyclophosphamide (PTCy) based regimens, early neutrophil engraftment, and patients with GVHD had better survival outcomes (p-value < 0.05) overall survival (OS), and relapse-free survival (RFS). and GVHD-free relapse-free survival (GFRS) were significantly better in cases with early neutrophil engraftment. OS of the study cohort was 50% while disease-free survival (DFS) and GFRS were 45.5% and 36.4%, respectively.

Immune reconstitution after single-unit umbilical cord blood transplantation using anti-thymoglobulin and myeloablative conditioning in adults with hematological malignancies.

This study aimed to investigate the kinetics of immune recovery following umbilical cord blood transplantation (UCBT) in adults who received a myeloablative conditioning (MAC) regimen and antithymocyte globulin (ATG). While the immune recovery kinetics has been extensively studied in pediatric UCBT recipients, limited data exist for adults. We conducted a comprehensive analysis of 221 consecutive adult patients who underwent UCBT with MAC and ATG at a single institution. Our objective was to evaluate the influence of patient, disease, and transplant factors, along with acute graft-versus-host disease (aGVHD), on immune reconstitution and overall survival. Our findings confirm a delayed recovery of T cells, while B and NK cell reconstitution exhibited rapid progress, with NK cell counts reaching normal levels within 3 months post-transplantation and B cells within 6 months. Within CD3+ T cells, CD8+ T cells also experienced a delayed recovery (12 months), but to a lesser extent compared to CD4+ T cells (18 months). Delayed immune recovery of T-cell subsets was associated with the development of aGVHD grade II-IV, older age, CMV negativity, and a female donor. Patients with lymphoproliferative diseases showed slower NK cell recovery. Our study demonstrates that adult patients undergoing MAC with ATG and receiving a single unit UCBT for hematologic malignancies experienced rapid reconstitution of NK and B cells. However, T cell recovery, particularly CD4+ T cells, was significantly delayed. To enhance T cell recovery, it may be crucial to consider UCB units with higher cellularity and optimize ATG doses in conditioning.

Donor whole blood DNA methylation is not a strong predictor of acute graft versus host disease in unrelated donor allogeneic haematopoietic cell transplantation.

Allogeneic hematopoietic cell transplantation (HCT) is used to treat many blood-based disorders and malignancies, however it can also result in serious adverse events, such as the development of acute graft-versus-host disease (aGVHD). This study aimed to develop a donor-specific epigenetic classifier to reduce incidence of aGVHD by improving donor selection. Genome-wide DNA methylation was assessed in a discovery cohort of 288 HCT donors selected based on recipient aGVHD outcome; this cohort consisted of 144 cases with aGVHD grades III-IV and 144 controls with no aGVHD. We applied a machine learning algorithm to identify CpG sites predictive of aGVHD. Receiver operating characteristic (ROC) curve analysis of these sites resulted in a classifier with an encouraging area under the ROC curve (AUC) of 0.91. To test this classifier, we used an independent validation cohort (n = 288) selected using the same criteria as the discovery cohort. Attempts to validate the classifier failed with the AUC falling to 0.51. These results indicate that donor DNA methylation may not be a suitable predictor of aGVHD in an HCT setting involving unrelated donors, despite the initial promising results in the discovery cohort. Our work highlights the importance of independent validation of machine learning classifiers, particularly when developing classifiers intended for clinical use.

Reduced Cytokine Release Syndrome and Improved Outcomes with Earlier Immunosuppressive Therapy in Haploidentical Stem Cell Transplantation

The optimal timing of immunosuppression and post-transplantation cyclophosphamide (PTCy) in haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is unknown. However, cytokine release syndrome (CRS) following haplo-HSCT is associated with worse transplantation outcomes, and the incidence of CRS may be affected by the timing of immunosuppression and PTCy. In this study, we compared CRS and other transplantation outcomes in 2 cohorts receiving different immunosuppression and PTCy schedules following haplo-HSCT. This was a retrospective cohort study of 91 patients who underwent haplo-HSCT at the Intermountain Health Blood and Marrow Transplant Program. The original or standard haplo-HSCT GVHD prophylaxis regimen included PTCy on days +3 and +4, with mycophenolate mofetil (MMF) and tacrolimus starting on day +5. The modified regimen adopted in November 2020 changed PTCy to days +3 and +5, with earlier introduction of tacrolimus and MMF, on day -1 and day 0, respectively. Grade ≥1 CRS occurred in 32% of patients in the modified regimen, in 82% of patients in the standard regimen (P <.0001), and 65% overall. Likewise, grade ≥2 CRS was lower with the modified regimen (16% versus 57%; P = .0002). The mean duration of CRS symptoms was longer with the standard regimen (3.14 days versus 1.44 days; P = .0003). The incidence of acute graft-versus-host disease grade III-IV or extensive chronic GVHD (cGVHD) at 1 year was lower in the modified regimen (6% versus 32%; P = .0068). No differences between the standard and modified regimens were seen in overall survival, relapse, or GVHD-free relapse-free survival (GRFS), although there appeared to be a trend toward improved GRFS with the modified regimen. Post hoc analysis comparing GRFS in patients with CRS and those without CRS found that CRS was associated with lower GRFS at 1 year (36% versus 63%; P = .0138). The duration of broad-spectrum antibiotic therapy was decreased by 7.5 days (P = .0017) and the time to hospital discharge was reduced by 7.1 days (P = .0241) with the modified regimen. This is the first analysis to evaluate and find a difference in CRS with early initiation of immunosuppressive therapy in haplo-HSCT. Our results suggest that this modified GVHD regimen benefits patients by reducing CRS and high-grade GVHD compared to the standard PTCy-based GVHD prophylaxis regimen in haplo-HSCT. Additionally, this novel regimen did not appear to negatively impact outcomes.

Donor Lymphocyte Infusion for Relapsed Acute Leukemia or Myelodysplastic Syndrome after Hematopoietic Stem Cell Transplantation: A Single-Institute Retrospective Analysis.

Objective The prognosis of the patients who relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poor, and therapeutic options are limited. In the present study, we investigated the efficacy and factors associated with the survival in patients with acute leukemia or myelodysplastic syndrome (MDS) who relapsed following allo-HSCT and were treated with donor lymphocyte infusion (DLI) in real-world practice. Patients Twenty-nine patients with acute myeloid leukemia21, acute lymphoid leukemia4 or MDS4 were enrolled. Eleven patients were diagnosed with hematological relapse, and 18 were diagnosed with molecular or cytogenetic relapse. Results The median injection number and median total number of infused CD3+ T cells were 2 and 5.0×107/kg, respectively. The cumulative incidence of acute graft-versus-host disease (aGVHD) of grade ≥II at 4 months after the initiation of DLI was 31.0%. Extensive chronic graft-versus-host disease (cGVHD) occurred in 3 (10.3%) patients. The overall response rate was 51.7%, including 3 cases of hematological complete remission (CR) and 12 cases of molecular/cytogenetic CR. Cumulative relapse rates at 24 and 60 months following DLI in patients who achieved CR were 21.4% and 30.0%, respectively. The overall survival rates at 1, 2 and 3 years after DLI were 41.4%, 37.9% and 30.3%, respectively. Molecular/cytogenetic relapse, a longer interval from HSCT to relapse, and concomitant chemotherapy with 5-azacytidine (Aza) were significantly associated with a relatively long survival following DLI. Conclusion These results indicated that DLI was beneficial for patients with acute leukemia or MDS who relapsed after allo-HSCT and suggested that DLI in combination with Aza for molecular or cytogenetic relapse might result in favorable outcomes.

Early Hematopoietic Reconstitution Status after Haploidentical Transplantation in AML Patients Is Indicative of Early Complications

Objective To investigate the early hematopoietic reconstruction process of haploidentical allogeneic hematopoietic stem cell transplantation (haplo-allo-HSCT) in patients with acute myeloid leukemia, and to explore its correlation with the occurrence of early complications after transplantation. Methods A retrospective analysis was performed on the clinical information of 187 AML patients who underwent haploidentical allo-HSCT at the Hematology Hospital of the Chinese Academy of Medical Sciences from January 2017 to December 2022, and all of these patients achieved complete remission before transplantation. The results of pre-transplantation-7d-after-tranplantation+14d blood routine were analyzed. The occurrence of aGVHD within 100 days after transplantation was the primary outcome event, and CMV infection within 60 days was the secondary outcome event. The diagnosis and grading of aGVHD is described in Glucksberg and MAGIC. R-4.2.0 statistical software was used for statistical analysis. Results A total of 187 AML patients who underwent haploid transplantation after achieving complete remission were included, with a median age of 35 (27-55) years, including 105 male patients (56.31%) and 82 female patients (43.69%). All patients were grouped into aGVHD patients according to different risk levels: (1) There were differences between the I~IV°aGVHD group and the patients without aGHVD (100 versus 87 patients) in the early post-transplantation plt and WBC absolute levels, and the I~IV°aGVHD group showed a lower plt trend in 1d and 2d, and a higher WBC level (0.08×10 9/L vs 0.07×10 9/L, p=0.036) at 10 days. (2) Compared with patients without aGHVD (70 versus 87 cases), the former showed lower plt levels (62.5×10 9/L vs 80×10 9/L, p=0.029) in 1d and higher WBC levels (0.03×10 9/L vs 0.02×10 9/L, p=0.047; 0.11×10 9/L vs 0.07×10 9/L, p=0.033) in 9d~10d), the Hb level was lower at 1d~3d (91g/L vs 99g/L, p=0.047; 91g/L vs 97.5g×109/L, p=0.039; 89.5g/L vs 95.5g/L, p=0.013). (3) Compared with patients without aGHVD (33 versus 87 patients), the III~IV°aGVHD group showed lower plt levels (60×10 9/L vs 74×10 9/L, p=0.006; 48×10 9/L vs 52×10 9/L, p=0.018; 26×10 9/L vs 36.5×10 9/L, p=0.003) in 1~3d, and high WBC level (0.04×10 9/L vs 0.02×10 9/L, p=0.025; 0.14×10 9/L vs 0.07×10 9/L, p=0.008) showed in 10 days, and lower Hb level in 1d~3d (89g/L vs 99g/L, p=0.047; 89g/L vs 97.5g/L, p=0.039; 83g/L vs 95.5g/L, p=0.013). Based on the maintenance of platelets at 20×109/L for 3 days after transplantation, the cumulative incidence of 100 days III~IV°aGVHD in the ≤3d group was higher (63% vs 30%, p=0.015). Univariate analysis showed that the absolute value of 1~3d plt after transplantation was low, and the PLT maintained at 20×10 9/L after HSCT was short, which was a risk factor for the occurrence of aGVHD. Group analysis of CMV occurring within 60 days showed that in the early post-transplantation period, patients in the non-CMV group had higher absolute platelet values (63.50×10 9/L vs 47.00×10 9/L, p=0.03) than patients in the CMV group at 0 days. Age, pretreatment regimen, transplant type, aGVHD prevention regimen, time to first PLT infusion after transplantation, absolute value of 0 d platelets, and platelet transfusion efficiency were included in univariate and multivariate analysis, and multivariate analysis showed that pretreatment regimen (p=0.017, 1.002 [0.606-0.953]) and transplant type (p&amp;lt;0.001, 0.264 [0.147-0.476]) were independent risk factors affecting the occurrence of CMV. No correlation between platelet transfusion efficiency and PLT infusion frequency and CMV was found. Conclusion Early hematopoietic reconstruction after transplantation in AML-CR patients who received haploid transplantation has certain indicative significance for the occurrence of early complications, and its indicative significance becomes more significant with the increase of aGHVD degree.

Recipient Resident Macrophage Plays a Crucial Role in Acute Graft-Versus-Host-Disease after Allogeneic Stem Cell Transplantation By Regulation of Damage-Associated Molecular Pattern Phagocytosis

Introduction Evidence shows allogeneic hematopoietic stem cell transplantation (alloHSCT) provides life-sustaining therapy for many hematologic malignancies. Unfortunately, in many cases it is complicated by acute-graft-versus-host disease (aGVHD), a life-threatening sequela. Most interstitial tissues contain populations of resident macrophages. Multiple studies have investigated the role of infiltrating macrophages in aGVHD, but little is known about the role of resident macrophage in aGVHD. To address this issue, we adopt a LysM cre/cre-Hif1a flox/flox mice (KO)as host mice with abnormal macrophage whose host resident macrophage remains unchanged early after allo-HSCT. KO mice received alloHSCT after Total body irradiation (TBI) from wild-type(WT) mice of BALB/c background. The neutrophil and circulating monocyte/macrophage were replaced by WT cells and the resident macrophage remains unchanged after this procedure. The grade of aGVHD and survival was observed. Methods Recipient mice are on the background of C57BL/6(H-2 b), and donor mice are wild-type BALB/c (H-2 d ) mice. All mice used were 8-12 week old. All animal experiment protocols were approved. LysM cre/cre (CRE) mice were taken as control recipients. Mice were exposed to TBI split into two doses separated by 4h. KO and CRE C57/BL mice received 9 Gy TBI. 18h after irradiation, mice of two groups were injected i.v with 1×10 7BM cells and 1.5×10 7 splenocytes isolated from WT BALB/c mice. aGVHD score and survival are monitored daily. Isolation of Kupffer subsets was performed as CD45 +CD11b + Ly6G -F4/80 +, which from KO and CRE mice of GVHD model were taken to do single-cell sequencing assay. Survival curves were plotted by the Kaplan-Meier method. The statistical significance between group means was determined using t-test by Graphpad prism9.5. The level of significance was set at P&amp;lt;0.05. Results The mean survival of KO mice is 18.6 days (95%CI 14.06-22.6) post alloHSCT, while the mean survival of control mice is 37.6 days (95%CI 29.7-45.6)(n=8)( P &amp;lt;0.001). Weight loss (% of baseline weight on the day of TBI) starts to differ on day 14 post-HSCT, with the KO group of 101.7 and Control group of 84.9 ( P &amp;lt;0.05). GVHD score starts to differ on day 10 post-HSCT, with the KO group of mean score 5.1 and control group 3.9 ( P &amp;lt;0.05)(n=8) (Figure1). The GVHD score remains statistically different till day 24 post-HSCT. On day 24, all KO mice die while one control mouse live up to 58 days. The liver function presented by ALT is different on day 14 post-HSCT, KO group with mean ALT 209.0 U/L is higher than Control group whose mean ALT is 64.9U/L(n=4). On day 21, Liver GVHD pathology score of the KO group is 7, compared to 5.2 of the control group(n=6)( P&amp;lt;0.05). Thus, KO mice present with a more severe aGVHD phenotype than CRE mice. Macrophage is known to have deficient phagocytosis ability when lacking Hif1-a, which is also confirmed through phagocytosis assay in our lab by FITC marked particles based on melamine resin ( P &amp;lt;0.05). We hypothesize the disability of phagocytosis of recipient resident macrophage renders more DNA debris (also known as DAMP) generated from conditioning, leading to susceptibility of aGVHD, we applied Dnase I to mice from day4 to day14 post-HSCT. The survival of KO mice after injection of Dnase I, with a mean survival of 39.9 days, is better than KO mice with vehicle injection ( P &amp;lt;0.05). After Dnase I injection, KO group, compared to 63.5 days mean survival of the control group, there is no statistical difference ( P=0.113). In order to look into more mechanisms, CD45 + cells from the liver of KO and CRE mice with GVHD model 21 days post-HSCT were isolated to do single-cell sequencing. KO mice revealed more T cell ratio than CRE mice. GO analysis revealed several abnormalities including regulation of lymphocyte activation. Conclusions We build GVHD model on LysM cre/cre-Hif1a flox/flox and LysM cre/cre mice, both adopt alloHSCT from wild-type BALB/c mice. After HSCT, both groups are replaced with wild-type neutrophils and circulating monocyte/macrophages, leaving resident macrophages different. KO mice present with exacerbated GVHD phenotype than CRE mice after alloHSCT. This difference could be mitigated by Dnase I injection. Thus, the resident macrophage of the recipient plays a crucial role in aGVHD occurrence, which is partly by regulation of DAMP phagocytosis.

Allogeneic Hematopoietic Stem Cell Transplantation for Elderly Acute Lymphoblastic Leukemia Patients: A Registry Study from the Société Francophone De Greffe De Moelle Et Thérapie Cellulaire (SFGM-TC)

Background There are very scarce data regarding the outcome of elderly patients with acute lymphoblastic leukemia (ALL) who received allogeneic hematopoietic stem cell transplantation (alloHSCT) as consolidation therapy in 1rst or higher complete remission (CR). Most studies evaluating the benefit of alloHSCT in ALL include both young and elderly populations. Thus, the optimal conditioning regimen still need to be determined in a frail population represented by patients over 60 years old. In addition, total body irradiation (TBI) dose is of first importance, as prior reports demonstrated its potential higher anti-leukemic effect. We here present the outcome of ALL patients older than 59 years from the Société Francophone de Greffe de Moelle et Thérapie Cellulaire (SFGM-TC) registry. Method This is a retrospective study. The primary outcome was overall survival (OS). Secondary outcomes were progression free survival (PFS), non-relapse mortality (NRM), relapse incidence (RI), acute Graft-versus-host disease (aGvHD) grade II-IV, chronic GvHD, neutrophil engraftment and GvHD-free relapse-free survival (GRFS). Competing risks analyses were performed to analyze NRM with competing event relapse, and aGvHD grade II-IV, chronic GvHD and neutrophil engraftment with competing events relapse and death. Univariable analyses were performed using the log-rang test for OS and PFS, while Gray's test was used for cumulative incidence (CI). Multivariable analyses were performed using the Cox proportional hazards regression model including age, ALL subtype, time from diagnosis to alloHSCT, disease status at alloHSCT, donor to patient CMV status, donor to patient sex, ATG use, myeloablative conditioning (MAC), TBI use. Results A total of 316 patients ≥ 60 years old transplanted for ALL from 2012 to 2022 in 36 participating centers were included in this study. Patient's characteristics are described in Table 1. With a median follow up of 34.5 months (IQR 29.5-38.8), 3-year OS was 46% (95% CI 40-53%) (Figure 1A) with only the disease status at transplant impacting negatively OS, 53% (95% CI 46-60%) in CR1, 32% (95% CI 21-49%) in CR2, 29% (95% CI 13-63%) in advanced disease, p=0.002 and the ALL subtype, 59% (95% CI 51-68%) in Ph+ ALL, 40% (95% CI 29-54%) in Ph- ALL, 34% (95% CI 20-55%) in T-ALL, 20% (95% CI 9-42%) in other/NA, p&amp;lt;0.001. 3-year PFS was 41% (95% CI 35-48%) (Figure 1B) with the disease status at transplant impacting negatively, 49% (95% CI 42-57%) in CR1, 26% (95% CI 16-42%) in CR2, 22% (95% CI 9-58%) in advanced disease, p&amp;lt;0.001, the ALL subtype, 51% (95% CI 42-61%) in Ph+ ALL, 41% (95% CI 31-54%) in Ph- ALL, 21% (95% CI 10-41%) in T-ALL, 21% (95% CI11-43%) in other/NA, p&amp;lt;0.001, year of HSCT worse &amp;lt; 2018, p=0.007, CMV -/- worse, p=0.033, absence of TBI worse, p=0.018. 3-year NRM was 23% (95% CI 18-28%) (Figure 1C) and none of the factors impacted it. 3-year RI was 36% (95% CI 31-42%) (Figure 1D) with the disease status at transplant impacting negatively, 29% (95% CI 23-36%) in CR1, 50% (95% CI 35-63%) in CR2, 56% (95% CI 26-77%) in advanced disease, p=0.0042, the ALL subtype, 26% (95% CI 19-34%) in Ph+ ALL, 43% (95% CI 31-54%) in Ph- ALL, 57% (95% CI 38-73%) in T-ALL, 42% (95% CI 25-59%) in other/NA, p=0.0064, year of HSCT worse &amp;lt; 2018, p=0.0216, CMV -/- worse, p&amp;lt;0.001, absence of TBI worse, p=0.0069, MRD worse, p=0.0111. 3-year GRFS was 30% (95% CI 25-37%) with the disease status at transplant impacting negatively, 35% (95% CI 28-43%) in CR1, 22% (95% CI 13-37%) in CR2, 23% (95% CI 9-59%) in advanced disease, p=0.029, the ALL subtype, 37% (95% CI 30-47%) in Ph+ ALL, 33% (95% CI 23-46%) in Ph- ALL, 15% (95% CI 7-32%) in T-ALL, 17% (95% CI 8-38%) in other/NA, p=0.0029, year of HSCT worse &amp;lt; 2018, p&amp;lt;0.001. CI of aGVHD grade II-IV was 33% (95% CI 28-38%), grade III-IV 11% (95% CI 8-15%), cGVHD 35% (95% CI30-41%), extensive cGVHD 21% (95% CI 16-26%).Multivariable analyses confirmed a worse OS and PFS for advanced disease, with a HR of 1.79 (95% CI 1.22-2.64), p=0.00322 and ALL subtype with a HR for other than Ph+ ALL of 1.99 (95%CI 1.42-2.79). Conclusion: This study suggests that alloHSCT is a reasonable option for elderly ALL patients without any impact of age but advanced disease and ALL subtype other than Ph+ ALL negatively influenced the outcome.

Prognostic Factors Impacting Post-Transplant Outcomes in Adult T-Cell Acute Lymphoblastic Leukemia: A Registry-Based Study By the EBMT Acute Leukemia Working Party

Background: T-cell acute lymphoblastic leukemia (T-ALL) predominantly affects individuals in late childhood and young adulthood and historically had high mortality rates. The outcome of Pediatric inspired chemo protocols in the T-ALL have improved in the past years due to the advancement in treatment and supportive care but the data is less mature, although adult patients still face challenges. Limited studies have directly explored the impact of patient- and transplant-related factors on post-transplant outcomes in adult T-ALL patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: A retrospective registry-based analysis was conducted across multiple centers using data from the European Society for Blood and Marrow Transplantation (EBMT) registry. Inclusion criteria were adult T-ALL patients (&amp;gt;18 years old) who underwent their first allo-HSCT in first complete remission from matched sibling donors (MSD), unrelated donors (UD) (10/10 or 9/10) or haploidentical donors between 2010 and 2021. Cord bloods were excluded. Multivariable Cox regression analysis was performed to examine the associations between patient/transplant characteristics and outcomes. Results: A total of 1907 patients were included in the study. The median age at transplant was 33.4 years (18.1-75). The median follow up was 2.9 years (2.6-3.1), and the median year of HSCT was 2016 (2010-2021). Patients were 70 % male with 67% being CMV-positive, at the time of transplant. Donors were predominantly male (64%), and (23%) of transplants involved female donors to male patients. The median period between diagnosis and HSCT was 5.9 months (0 -23.8). Most transplants were from matched sibling donors (MSD) (45%) followed by UD (43%) and 12% were from Haploidentical transplants. Most patients underwent myeloablative conditioning with total body irradiation (TBI)-based regimens (69%) and most patients received peripheral blood stem cells (84%). Cyclosporine with methotrexate was the most common graft-versus-host-disease (GVHD) prophylaxis (54 %). In vivo T cell depletion was used in 44%. The 2-year overall survival (OS) was 69.4%, and leukemia -free survival (LFS) was 62.1%. The cumulative incidence of acute GVHD (aGVHD) grades II-IV at 100 days was 32.6%, and grades III-IV was 10%. The cumulative incidence of chronic GVHD (cGVHD) at 2 years was 37.3%, and extensive cGVHD was 16.8%. Multivariate analysis yielded significant associations between patient/transplant characteristics and outcomes. Advanced age at transplant was associated with poorer outcomes, including LFS (HR=1.11, p=0.004), GVHD-free, relapse-free survival (GRFS) (HR=1.06, p=0.04), OS (HR=1.12, p=0.002), and higher non-relapse mortality (NRM) (HR=1.23, p=0.001); HR for 10y increment. A later year of HSCT was associated with improved GFRS (HR=0.89, p=0.001), OS (HR=0.9, p=0.02), and decreased NRM (HR=0.82, p=0.008), aGVHD II-IV (HR=0.83, p=0.001), and cGVHD (HR=0.8, p=0.001); HR for 3y increment. TBI was specifically superior with improved LFS (HR=0.79, p=0.02), GRFS (HR=0.83, p=0.04), and lower relapse incidence (RI) (HR=0.65, p=0.001). Female-to-male transplant combination had a negative impact on GFRS (HR=1.21, p=0.02), OS (HR=1.23, p=0.048), and on the risk of cGVHD in general (HR=1.39, p=0.002) and specifically extensive cGVHD (HR=1.47, p=0.01). The use of in vivo T-cell depletion had significant benefits in terms of GFRS, aGVHD grade III-IV, cGVHD, and extensive cGVHD. Conclusion: This large study identified prognostic factors, such as age at transplant, donor type, and conditioning regimen, in influencing key outcomes including OS, LFS, GVHD incidence, and NRM in adult T-ALL patients undergoing allo-HSCT. Importantly, a significant improvement over time in post-transplant outcomes was noted. These findings hold great promise for new adapted treatment strategies and can serve as a benchmark for future studies in that setting.

CD7 CAR-T Therapy Followed By a Second Transplant for T-Cell Acute Lymphoblastic Leukemia or Lymphoblastic Lymphoma Patients Who Relapsed after a Prior Transplant

Background The therapeutic options for patients with T-cell acute lymphoblastic leukemia or lymphoblastic lymphoma (T-ALL/LBL) who relapse after hematopoietic stem cell transplantation (HSCT) are currently restricted. CD7-targeted chimeric antigen receptor (CAR) T-cell therapy provides a promising avenue towards remission, yet the long-term prognosis for these patients still needs to be improved. The advantages of progressing to a second transplant post-CAR-T treatment remain uncertain due to limited data. In this study, we analyzed the clinical characteristics and transplantation outcomes of 16 T-ALL/LBL patients who, having relapsed after their initial transplantation, achieved complete remission (CR) in bone marrow (BM) and CR/partial remission (PR) in extramedullary lesions via CD7 CAR-T therapy and then opted for a second allogeneic HSCT (allo-HSCT) at our center. Our aim is to explore strategies to enhance the survival rate of these patients. Methods From January 2021 to January 2023, we analyzed T-ALL/LBL patients who underwent second transplantation at Hebei Yanda Lu Daopei Hospital. The patients included in this study met the following criteria: they had relapsed following their first HSCT and had subsequently undergone CD7 CAR-T therapy prior to the second transplantation. The follow-up cut-off date was till June 1, 2023. The median follow-up duration after the second transplantation was 178 days, ranging from 9 to 500 days. Results A total of 16 patients including 13 with T-ALL and 3 with T-LBL were enrolled. There were 14 males and 2 females. The donor of first transplantation was autologous(n=3), sibling identical(n=2), unrelated donor(n=2), or haplo-identical (n=9). After the first transplantation, 8 patients relapsed in bone marrow (BM) and 8 relapsed both in BM and extramedullary sites. Of these, 13 patients received autologous CD7 CAR-T, one patient received donor-derived CD7 CAR-T, and one patient was treated with universal CAR-T cells. After the CD7 CAR-T therapy, all 16 patients (100%) achieved minimal residual disease (MRD)-negative CR in BM, and 6 out of 8 patients (75%) achieved CR in extramedullary lesions. Only two patients exhibited PR in the extramedullary lesions. The median age at the time of the second transplantation was 28 years (range 14-42 years). The median time from diagnosis to the second transplantation was 683 days (range 385-2672 days). The median interval between the first and second transplantation was 438 days (range 229-2540 days), and the median interval from CD7 CAR-T infusion to the second transplantation was 72 days (range 31-92 days). For the second transplantation, 13 cases had haplo-identical donors and 3 cases had unrelated donors. The conditioning regimens utilized were either total body irradiation (TBI)-based (n=9), busulfan-based (n=6), or melphalan-based (n=1). Following the 2 nd transplant, the 1-year overall survival(OS) and leukemia-free survival(LFS) were 58.5% (95% CI, 28.9-85.0%) and 51.4% (95% CI, 22.4-79.9%), respectively(Figure 1). The 1-year relapse incidence (RI) and non-relapse mortality (NRM) were 15.9% (95% CI, 4.4-57.8%) and 31.5% (95% CI, 13.2-74.9%), respectively. The cumulative incidence of CMV and EBV viremia at day 100 were 75.0% (95% CI, 56.5-99.5%) and 19.8% (95% CI, 7.2-54.6%), respectively. The cumulative incidence of all grades acute graft-versus-host disease (aGVHD) and 3-4 grade aGVHD at day 100 were 56.3% (95%CI, 36.5-86.7%) and 25% (95%CI, 10.7-58.4%), respectively. One-year chronic GVHD(cGVHD) was observed in 25.1% of the cases (95%CI, 9.3-67.4%), while moderate to severe cGVHD was not found in any patient. Following the 2 nd transplant, a total of 6 patients died, including 3 from infection, 2 from relapse and 1 from intracranial hemorrhage. Conclusions Our initial findings suggest that even in refractory/relapsed T-ALL/LBL patients who have experienced relapse following previous HSCT, MRD-negative complete remission can potentially be achieved utilizing CD7 CAR-T cell therapy. The subsequent implementation of a second allo-HSCT appears feasible. Combining CAR-T therapy with a follow-up second HSCT presents a strategy for these heavily pre-treated patients, offering promising prospects for survival. However, further evaluation of this treatment approach is required, necessitating long-term monitoring and a larger patient cohort.

Clinical Factors but Not Somatic Mutations Predict for Survival in Patients with Myelofibrosis Undergoing Allogeneic Hematopoietic Cell Transplant: Analysis of the North American Myelofibrosis Transplant Outcome (NAMTO) Study

Introduction: Myelofibrosis (MF) is a clonal hematologic malignancy characterized by constitutive JAK-STAT activation and aberrant cytokine signaling. Allogeneic hematopoietic stem cell transplantation (allo-HCT) remains the only potentially curative therapy in MF. The contribution of disease-, patient- and donor-related factors to allo-HCT outcomes remains to be fully elucidated, as well as the presence of somatic mutations in genes such as ASXL1, EZH2, SRSF2, U2AF1 and IDH1/2 which are associated with worse prognosis in MF patients (pts). In this large multi- center retrospective analysis, we aimed to study the impact of clinical and molecular mutations on transplant outcomes. Methods: This analysis including 498 pts from 11 centers in North America and Canada. Univariate proportional-hazard Cox regression analysis stratified by center was used to assess the association of patient, transplant, and disease characteristics on overall survival (OS). Baseline patient demographic data and disease characteristics were selected as covariates in the multivariate analysis. Results: Pts transplanted between 2002-2021 were included in this analysis. Baseline and transplant characteristics are summarized in table 1. The 1- and 2-year OS was 77% (95% CI; 73-81) and 70% (95% CI; 66-74) and non-relapse mortality (NRM) 19% (95% CI: 17-21) and 23% (95% CI: 19-27), respectively. The cumulative incidence (CMI) of relapse at 1- and 2-years was 12% (95% CI; 10-14) and 16% (95% CI; 12-20). The CMI of acute graft versus host disease (aGVHD) grade II-IV was 31% (95% CI; 27-35) at 3 months and 42% (95% CI; 38-46) at 1-year post-transplant and grade was III-IV 13% (95% CI; 11-15) and 18% (95% CI; 14-22), respectively. The CMI of neutrophil engraftment at 1 and 3 months was 90% (95% CI: 87-93) and 97% (95% CI: 95-95) and for platelets 55% (95% CI: 50-59) and 80% (95% CI: 76-83). Univariate analysis included pts (age and gender), transplant (donor type and conditioning regimen intensity) and disease characteristics (DIPSS, mutations, cytogenetics (CG), blood counts, and spleen size). Hemoglobin &amp;gt; 10 g/dL (HR .5, 95% CI .34 -.73 p=3 x 10 -4) and platelets &amp;gt;50× 10 9/L (HR .59, 95% CI .42-.81, p=.0013) prior to transplant were associated with improved OS. High risk DIPSS was associated with decreased OS (p=0.0002). Mutations in ASXL1, EZH2, IDH1/2, U2AF1 and SRSF2 were not associated with decreased OS in this analysis (Figure 1). However, mutations in ZRSR2 were associated with inferior OS (HR 2.07, 95% CI 1.08-3.95, p=.0252). Lastly, JAK2 which had the most frequent mutations was not associated with OS (HR .0.93, 95% CI .65-1.31). There was no association between the CG risk groups and OS. Splenomegaly, measured radiographically, had no impact on OS but was strongly associated with engraftment (better engraftment defined as HR&amp;gt;1). For platelets, spleen size of 15.6-18.9 cm HR of 0.69 (95% CI .47-1, p=.0489) and size &amp;gt;18.9-22.5 cm HR of 0.48 ( 95% CI .33-.7, p=1x10^-4). For neutrophils, spleen size &amp;gt;19.9-22.5 cm had a HR of 0.68, (95% CI .48-.96, p=.0268) and size&amp;gt;22.5 cm had a HR of 0.65 (95% CI .46-.91, p=.0114). Mismatched unrelated (MMURD) and haplo identical donors had no impact on survival but were associated with delayed platelet engraftment; MMURD (HR .67, 95% CI .47-.96, p=.0298) and haploidentical donors (HR .56, 95% CI .39-.8, p=.0017). In a multivariate analysis adjusted for age, gender, highest DIPSS, donor type and conditioning regimen, platelets &amp;gt; 50× 10 9/L (HR .61, 95% CI .44-.87, p=.0053) hemoglobin &amp;gt;10 g/dL (HR .6, 95% CI .4-.9, p=.0244) and lower DIPSS at the time of transplant were associated with improved OS. Conclusions: In this large multicenter analysis only clinical variables; hemoglobin and platelets, were found to be associated with OS after allo-HCT in MF patients. Somatic mutations associated with poor prognosis were not associated with OS suggesting that transplant can overcome their negative impact. Splenomegaly was associated with delayed engraftment but not OS. Interestingly, using alternative donors (MMURD and haplo identical) didn't have a negative effect on OS, possibly reflecting the use of post-transplant cyclophosphamide for GVHD prophylaxis in recent years. These results highlight the importance of biologic factors in the prognostication of outcomes in MF pts undergoing allo-HCT independent of somatic mutations. Supported by the American Society of Hematology (ASH) and MPN Research Foundation

Clinical Outcomes of Patients Receiving 3 Versus 4 Doses of Methotrexate with Concomitant Anti-Thymocyte Globulin; A Single Center Experience

Background: Four doses of methotrexate (MTX) given on day +1, +3, +6, and +11 after allogeneic stem cell transplant (HSCT) is considered one of the most common graft-versus-host disease (GVHD) prophylaxis regimen. However, mucositis and occasionally transaminitis prohibit safe delivery of the fourth dose of MTX. Prior single institution studies showed conflicting results comparing the outcomes of patients who received 3 vs 4 doses of MTX but to our knowledge, the effect of concomitant anti-thymocyte globulin (ATG) use has not been reported. As both ATG and MTX synergistically prevent GVHD via suppressive effects on T-cells. Our institution uniquely incorporates ATG as part of the conditioning regimen for patients receiving HSCT from 10/10 loci match unrelated donors (MUD) and here we report the clinical outcomes between patients who received 3 versus (vs) 4 doses of MTX. Methods: We retrospectively reviewed the charts of patients who underwent HSCT from MUD between 2009 to 2023 at the University of Iowa Hospital and Clinics. We use rabbit ATG (Thymoglobulin R), given at 0.5 mg/kg on day -3, 2 mg/kg on day -2, and 2.5 mg/kg on day -1. MTX is given at 15 mg/m 2 on day +1 and 10 mg/m 2 on day +3, +6 and +11 per institutional protocol. Statistical Analysis: Time was calculated from transplant to recurrence or death for recurrence-free survival (RFS) and overall survival (OS), respectively. For acute and chronic GVHD (aGVHD and cGVHD), time was calculated from transplant to onset of acute and chronic GVHD. Relapse and death were considered as competing events. For non-relapse mortality (NRM), time was calculated from transplant to death; relapse was considered a competing event. Cox regression and Fine-Gray competing risk models were used to estimate the effect of patient, disease, and treatment characteristics on outcomes Results: We identified 296 patients with various indications of HSCT; the most common was acute myeloid leukemia (45.3%). There were 117 and 179 patients who received 3 doses and 4 doses of MTX respectively. Patients characteristics reported in table 1. Median follow-up was 21.9 months (range 0.6 to 150.8). Patients who received 4 doses of MTX were more frequently male (68.2% vs 49.6%, p&amp;lt;0.01), received a reduced intensity (compared to myeloablative) preparative regimen (38.0% vs 23.1%, p&amp;lt;0.01), were older (median 58 vs 54 years, p=0.01), and underwent transplant at an earlier year (median year of transplant 2014 vs 2018, p&amp;lt;0.01). Severe mucositis was the most common reason for omission of the 4 th dose of MTX. Maximum grade of aGVHD was similar between cohorts (p=0.83). A statistically significant difference was not evidenced between patients receiving 4 versus 3 doses of MTX for the following outcomes: aGVHD (HR 1.11, 95% CI 0.84-1.46), grade 3-4 aGVHD (HR 1.41, 95% CI 0.77-2.60), RFS (HR 1.01, 95% CI 0.66-1.56), NRM (HR 1.33, 95% CI 0.84-2.10) and OS (HR 1.21, 95% CI 0.87-1.69). While significant on univariate analysis, MTX dose was not significantly associated with extensive cGVHD (HR 1.44, 95% CI 0.92-2.26) after adjustment for transplant year. Additionally, the median time to neutrophil engraftment was 14 days in both cohorts. Conclusion: When ATG is used concomitantly, omission of the 4 th dose of MTX does not significantly impact the rate of neutrophil engraftment, cumulative incidence of aGVHD, cGVHD, RFS, NRM, and OS after HSCT from MUD. However, a small sample size and non-randomized nature of this study prompts further confirmation study from a large prospective multicenter randomized control trial.

Checkpoint Inhibitors and Allo-SCT in Hodgkin Lymphoma: A Matter of Time - a Study By the SFGM-TC

Introduction: Allogeneic stem cell transplantation (allo-SCT) for patients with relapsed/refractory Hodgkin lymphoma (r/R HL) after autologous transplantation is now an established option. Many patients receive Check-Point Inhibitors (CPI) as relapse treatment. Nevertheless, concerns have been previously reported on higher risk of acute graft versus host disease (aGVHD) after CPI exposure, without any control group to elucidate risk factors. Methods: We conducted a multicentric retrospective case control study on behalf of the Francophone Society for Bone Marrow Transplantation and Cell Therapy to compare outcomes after allo-SCT for patients with r/R HL who were exposed or not exposed to CPI. Results: Between 2015 and 2018, 149 patients underwent allo-SCT for r/R HL in 21 centers. CPI was used for 50 patients (n=48 Nivolumab, n=2 Pembrolizumab). We did not identify any differences regarding baseline characteristics. Reduced intensity conditioning (RIC) was commonly used (90.2%), with Peripheral Blood Stem Cells (75.7%). A majority of patients had haploidentical (44.6%), followed by siblings (28.4%), matched unrelated (24.3%) and mismatched unrelated donors (2.7%). Cumulative incidence (CI) of aGVHD grade ≥II in the whole cohort was 39.6% and 14.8% developed a severe form (grade III-IV). There were no differences between CPI (n=50) and no CPI cohorts (n=99), regarding CI of aGVHD of any grade (respectively 58% and 57.6%, p=1.00), grade ≥II (respectively 36% and 41.4%, p=0.65), severe aGVHD (grade III-IV, respectively 12% and 16.2%, p=0.67) and chronic GVHD (respectively 26% and 34.3%, p=0.24), as described in Table 1. We did not observe excess of mortality from GVHD between both groups. The time interval between the last CPI injection and allo-SCT was found to be the only significant factor associated with a higher incidence and severity of aGVHD, as depicted in Figure 1. The median time from the last CPI injection and allo-SCT was 50 days [33;103]. Specifically, within 30 days, the incidence of severe aGVHD was significantly increased at 41.7% compared to only 2.7% in the control group (p=0.002). No severe forms were observed after 60 days, but it persisted a higher risk of aGVHD grade ≥II even after 60 days of delay. Thus, a higher percentage of patients required systemic therapy for aGVHD within 120 days compared to after 120 days (45% vs 0% respectively, p=0.03). The delay of CPI treatment did not impact the CI and severity of chronic GVHD or CI of relapse after allo-SCT. Of note, post-transplant cyclophosphamide did not reduce CI of aGVHD. With a median follow-up of 34.7 months, the 2-year Overall Survival, Relapse Free Survival and GVHD free, Relapse Free Survival (GRFS) were respectively 69.9% (IC95 41.1-78.5), 67.1% (IC95 58.8-76.7) and 48.5% (IC95 40.3-58.4), without differences between CPI and no CPI cohorts. Two-year non relapse mortality was 17.4% in whole cohort, without hepatic sinusoidal obstruction syndrome nor steroid-requiring febrile syndrome in CPI cohort. Conclusion: CPI use before allo-SCT within 60 days before allo-SCT can lead to significant severe aGVHD, with persisting higher risk of aGVHD grade ≥II even after 60 days of delay. This highlights the importance of exercising caution when administering CPI injections within 60 days before allo-SCT. There is need to develop GVHD prophylaxis strategies in this population at risk. The findings from this study may help inform clinical decision-making and management of HL patients undergoing allo-SCT.

A Prospective, Multi-Center, Randomized, Controlled Clinical Trial to Explore the Role of Mesenchymal Stem Cells in Preventing Graft Versus Host Disease

Background: There are few studies currently available on the prevention of GVHD by mesenchymal stem cells (MSCs) that use a systematic approach to prevent both aGVHD and cGVHD simultaneously. The clinical investigation of MSCs preventing either aGVHD or cGVHD independently is the main focus of the earlier studies. Aim:Using the strategy of co-transplantation of MSCs and HSCs and phased application of MSCs after transplantation (MSCs 100-day scheme), we seek to develop a secure and dependable system that can avoid both aGVHD and cGVHD based on our preliminary research. Method:Patients undergoing haploidentical adult hematopoietic stem cell transplantation will receive unaltered, fourth-generation UC-MSCs(Umbilical Cord). In addition to the usual GVHD preventive measures, UC-MSCs are given four hours before the transplantation of peripheral blood stem cells on day 0. UC-MSCs are administered once weekly for 1-4 weeks, once every 2-8 weeks, and once every 4-12 weeks after transplantation. The dose needed for each transfusion is 1 10 6/kg. Our research will look at how well UC-MSCs prevent GVHD following haplo-HSCT, as well as recurrence rates after transplantation, transplant-related issues, and the state of immunological reconstruction. the frequency, severity, 1- and 2-year survival rates, cumulative death rates, and the occurrence of aGVHD and cGVHD.Real-time tracking will be performed to monitor the occurrence of aGVHD and cGVHD, as well as their severity, frequency, 1-year and 2-year survival rates, and cumulative mortality rates. The analysis of the differences between the control group and the experiment will take into account the pre-transplant ferritin levels, CMV serological status of the donor-recipient, blood type matching situation, HLA locus matching situation, disease remission status, residual disease conditions, recipient age, donor-recipient gender matching situation, stem cell quantities (nucleated cells and CD34+ cell counts), and stem cell numbers (nucleated cells and CD34+ cell counts). Results: 96 patients from the MSCs group and 96 patients from the control group are now accessible for statistical purposes. Demographic factors for age and gender distribution do not differ considerably. Acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome-EB2, and acute mixed cell leukemia,which were all classified as having the same level of risk. The cumulative incidence of aGVHD grades II to IV is 19.8% in the MSCs group, while grades III to IV is 0%. Comparable indications for the control group are 43.8% and 9.3%, respectively. The overall incidence of aGVHD differs between the two groups in a statistically significant way (P=0.0047). The rates of moderate and severe cGVHD in the control group were 10.4% and 9.4%, respectively, whereas they were 13.5% and 4.2% in the MSCs group. Over the course of 1 year, the cumulative incidence of cGVHD for the MSCs group was 36.5%, compared to 39.6% for the control group. Regarding the overall two-year OS, there is no discernible difference between the MSCs group and the control group (P=0.43).While the MSCs group outperformed the control group in terms of GRFS (GVHD free and relapse free survival). Conclusion: The strategy of MSCs 100-day scheme infusion can successfully lower the incidence of acute and chronic GVHD and is beneficial for enhancing patient GRFS.

Data-driven grading of acute graft-versus-host disease

Despite advances in allogeneic hematopoietic cell transplantation, acute graft-versus-host disease (aGVHD) remains its leading complication, yet with heterogeneous outcomes. Here, we analyzed aGVHD phenotypes and clinical classifications in depth in large, multicenter cohorts involving 3019 patients and addressed prevailing gaps by developing data-driven models. We compared, tested and verified these along with all conventional classifications in independent cohorts and found that data-driven grading outperformed conventional grading in Akaike information criterion and concordance index metrics. Data-driven classifications refined aGVHD assessment with up to 12 severity grades, which were associated with distinct nonrelapse mortality (NRM) and confirmed the key role of intestinal aGVHD. We developed an online calculator for physicians to implement principal component-derived grading (PC1). These results provide substantial insight into the evaluation of aGVHD phenotypes and multiorgan involvement, which relegates the exclusive reporting of overall aGVHD severity grades in transplant registries and clinical trials. Data-driven aGVHD grading provides an expandable platform to refine classification and transplant risk assessment.

Post-Transplant Cyclophosphamide or ATG As Gvhd Prophylaxis in Mismatched Unrelated Stem Cell Transplantation? - a Registry Analysis By the EBMT Transplant Complications Working Party

There is an increased risk of GVHD and non-relapse mortality (NRM) after allogeneic stem cell transplantations (alloSCT) when mismatched unrelated donors (MMUD) are used. Prophylaxis with either rabbit anti-thymocyte globulin (rATG, also termed anti-T-lymphocyte globulin) or post-transplantation Cyclophosphamide (PTCy) is often used to reduce the risk of NRM and GVHD. However, it is currently impossible to give general recommendations regarding preference for rATG or PTCy since comparative evidence from larger data sets is lacking. To better understand the outcome of these GHVD prophylactic regimens, we analyzed outcomes of rATG vs. PTCy prophylaxis in adult patients with hematologic malignancies, who underwent peripheral blood alloSCT from 9/10 antigen MMUD between Jan 2018 and June 2021 in the EBMT database. We performed multivariate analyses using Cox cause-specific hazard models, adjusting for known risk factors, and variables that showed significant difference between the two comparison groups. Overall 2123 patient were included, treatment- and patient characteristics are shown in Table 1. Patients receiving PTCy (n=583) were younger and had undergone alloSCT more recently compared to patients receiving rATG (n=1540). Median follow up was 2.0 years (PTCy) and 2.4 years (rATG). Outcome graphs are shown in figure 1. All outcomes are given starting from AlloSCT (with 95% CI). NRM (fig 1A) was higher in the rATG arm (2-years NRM: PTCy 18% [14.6-21.6] vs. rATG 24.9% [22.7-27.3]; HR 0.74, p=0.03), Relapse incidence was slightly higher but not significant in the rATG arm (2-years RI: PTCy 22.9% [19.2 - 26.9] vs. rATG 26.2% [23.9 - 28.7]; HR 0.82, p=0.07), Overall survival (fig 1B) was better in the PTCy arm (2-years OS: PTCy 65.7% [61.2 - 69.9] vs. rATG 55.7% [52.9 - 58.3]; HR 0.77, p&amp;lt;0.001), same for Progression free survival (fig 1C) (2-years PFS: PTCy 59.1% [54.4 - 63.5] vs. rATG 48.8% [46.1 - 51.5]; HR 0.78, p=0.001). The incidences of chronic and acute GVHD were not significantly different between the groups; (2-years cGVHD: PTCy 31.7% [27.4 - 36] vs. rATG 30.3% [27.8 - 32.8]; HR 0.95, p=0.67. And 100-days aGVHD grades II-IV: PTCy 29.9% [25.9-34.1] vs. rATG 32.5% [30-34.9]; HR 0.83, p=0.11). In summary, we found significantly higher survival and lower NRM in recipients of peripheral blood alloSCTs from MMUD receiving PTCy as compared to rATG. The current analysis improves the evidence base for decision making on GVHD prophylaxis in MMUD alloSCT.