Matched unrelated donor transplantation versus haploidentical transplantation with post-transplant cyclophosphamide in children with acute myeloid leukemia: a PDWP-EBMT study.

In children with acute myeloid leukemia (AML) who lack an HLA identical sibling, the donor can be replaced with an HLA matched unrelated donor (MUD) or a haploidentical donor (haplo). We compared outcomes of patients <18 years with AML in first and second complete remission (CR1 and CR2) undergoing a hematopoietic stem cell transplantation (HCT) either with a MUD with anti-thymocyte globuline (ATG) (n=420) or a haplo HCT with PT-CY (n=96) after a myeloablative conditioning regimen (MAC) between 2011 and 2021, reported to EBMT. A matched pair analysis was performed to adjust for differences among groups. The final analysis was performed on 253 MUD and 95 haplo-HCTs. In the matched cohort, median age at HCT was 11.2 and 10 years and median year of HCT was 2017 and 2018, in MUD and haplo- HCT recipients, respectively. The risk of grade III-IV aGvHD was significantly higher in the haplo group (HR=2.33, 95%CI1.18-4.58, p=0.03). No significant differences were found in 2 years overall survival (OS; 78.4%vs71.5%; HR 1.39, 0.84-2.31, p=0.19), leukemia-free-survival (LFS; 72.7%vs69.5%; HR1.22, 0.76-1.95, p=0.41), CI of relapse (RI; 19.3%vs19.5%; HR=1.14, 0.62-2.08, p=0.68) non-relapse-mortality (NRM; 8%vs11%; HR=1.39, 0.66-2.93, p=0.39) and graft versus host free-relapse free survival (GRFS; 60.7%vs54.5%, HR=1.38, 0.95-2.02, p=0.09) after MUD and haplo-HCT respectively. Our study suggests that haplo-HCT with PT-CY is a suitable option to transplant children with AML lacking a matched related donor.

Post-transplant сyclophosphamide after matched donor hematopoietic stem cell transplantation in children with acute leukemia.

INTRODUCTION: The data on post-transplant cyclophosphamide (PTCy) in pediatric acute leukemia after matched allo-HSCT are limited to case series. The present study aimed to assess the results of PTCy-based GVHD prophylaxis in a large cohort of children with acute leukemia after matched allo-HSCT. METHODS: A retrospective analysis of 190 pediatric patients with acute leukemia who had a first allograft between 2008 and 2020 from a matched sibling donor (MSD) or matched unrelated donor (MUD) was carried out. In the MSD setting, GVHD prophylaxis consisted of PTCy alone (n = 28) for the study group, and calcineurin inhibitor (CNI) ± antimetabolite (n = 30) for the control group. In MUD setting, most patients in the study group received GVHD prophylaxis with PTCy+CNI+mycophenolate mofetil (n = 42, 66.7%) or PTCy+CNI+sirolimus (n = 12, 19%). All patients (n = 69) in the control group received ATG+CNI+antimetabolite. RESULTS: After MUD allo-HSCT, the incidences of acute GVHD grade III-IV and moderate/severe chronic GVHD were significantly lower in the PTCy group compared to control (6.6% vs. 35.0% and 12.7% vs. 47.1%, respectively, p < .0001). Five-year GVHD-free, relapse-free survival (GRFS) after MUD allo-HSCT was higher in the PTCy group compared to control (35.1% vs. 7.3%, p < .0001). At the same time, there was no significant difference between both groups after MSD allo-HSCT. CONCLUSIONS: In pediatric acute leukemia, PTCy-based GVHD prophylaxis for MUD allo-HSCT is a feasible and effective option that results in a low incidence of GVHD. Compared to the ATG-based approach, PTCy provides better control of GVHD in children. In pediatric allo-HSCT from MSD, PTCy demonstrates comparable effectiveness to conventional GVHD prophylaxis.

Trends in Outcome of Hematopoietic Stem Cell Transplantation: 5000 Transplantations and 30 Years of Single-Center Experience.

In this single-center analysis, we evaluated the trends in 5185 hematopoietic cell transplantations performed between 1990 and 2022. The study group comprised 3237 allogeneic (alloHCT) and 1948 autologous (autoHCT) hematopoietic cell transplantations. In the multivariate analysis, there was an improvement in event-free-survival (EFS) after autoHCT (HR 0.6, 95% CI 0.4-0.7, p < 0.0001) due to reduced cumulative incidence of relapse in the last five years (56% in 2010-2014 vs. 38% in 2015-2022). An improvement in EFS after alloHCT over time was observed (HR 0.33, 95% CI 0.23-0.48, p < 0.0001), which was due to reduced non-relapse mortality. No difference in cumulative relapse incidence was observed over the last decade for allografted patients. Survival after autoHCT improved in Hodgkin's disease (HR 0.1, 95% CI 0.1-0.3), multiple myeloma (HR 0.4, 95% CI 0.2-0.7) and solid tumors (HR 0.2, 95% CI 0.2-0.4), while after alloHCT, improvement was observed in acute myeloid leukemia (HR 0.3, 95% CI 0.1-0.5), acute lymphoblastic leukemia (HR 0.2, 95% CI 0.1-0.5), Hodgkin's disease (HR 0.1, 95% CI 0.0-0.4), non-Hodgkin's lymphomas and chronic lymphocytic leukemia (HR 0.2, 95% CI 0.0-0.6), inborn diseases (HR 0.2, 95% CI 0.2-0.4) and acquired aplastic anemia with matched related donors and matched unrelated donors (HR 0.3, 95% CI 0.2-0.8).

Allogeneic Hematopoietic Stem Cell Transplantation Activity in Inborn Errors of Immunity in Russian Federation.

PURPOSE: Allogeneic hematopoietic stem cell transplantation (HSCT) is an established therapy for many inborn errors of immunity (IEI). The indications for HSCT have expanded over the last decade. The study aimed to collect and analyze the data on HSCT activity in IEI in Russia. METHODS: The data were collected from the Russian Primary Immunodeficiency Registry and complemented with information from five Russian pediatric transplant centers. Patients diagnosed with IEI by the age of 18 years and who received allogeneic HSCT by the end of 2020 were included. RESULTS: From 1997 to 2020, 454 patients with IEI received 514 allogeneic HSCT. The median number of HSCTs per year has risen from 3 in 1997-2009 to 60 in 2015-2020. The most common groups of IEI were immunodeficiency affecting cellular and humoral immunity (26%), combined immunodeficiency with associated/syndromic features (28%), phagocyte defects (21%), and diseases of immune dysregulation (17%). The distribution of IEI diagnosis has changed: before 2012, the majority (65%) had severe combined immunodeficiency (SCID) and hemophagocytic lymphohistiocytosis (HLH), and after 2012, only 24% had SCID and HLH. Of 513 HSCTs, 48.5% were performed from matched-unrelated, 36.5% from mismatched-related (MMRD), and 15% from matched-related donors. In 349 transplants T-cell depletion was used: 325 TCRαß/CD19+ depletion, 39 post-transplant cyclophosphamide, and 27 other. The proportion of MMRD has risen over the recent years. CONCLUSION: The practice of HSCT in IEI has been changing in Russia. Expanding indications to HSCT and SCID newborn screening implementation may necessitate additional transplant beds for IEI in Russia.

Incidence of Common Herpesviruses in Colonic Mucosal Biopsies Following Hematopoietic Stem Cell Transplantation.

Intestinal complications are common after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, only scarce data concern herpesvirus incidence in the colonic mucosa post-HSCT. Our purpose was to assess the frequency and clinical significance of cytomegalovirus (CMV), Epstein−Barr virus (EBV), human herpesvirus type 6 (HHV6), and herpes simplex virus (HSV) in the colonic mucosa post-HSCT. The study group included 119 patients of different ages, mostly with leukemias and lymphomas, subjected to allo-HSCT from haploidentical related (48%) or HLA-compatible donors (52%). In total, 155 forceps biopsies of the colonic mucosa were taken in cases of severe therapy-resistant intestinal syndrome post-HSCT. Most samples were taken from the descending, sigmoid, and transverse colon. Intestinal GVHD or local infections were assessed clinically and by histology. EBV, CMV, HSV, and HHV6 were tested in colonic mucosal lysates with commercial PCR assays. HSV was found in <8% of colonic samples, along with high HHV6 and CMV positivity (up to 62% and 35%, respectively) and a higher EBV incidence at 5−6 months post-HSCT (35%). For CMV and EBV, significant correlations were revealed between their rates of detection in blood and colonic mucosa (r = 0.489 and r = 0.583; p < 0.05). No significant relationships were found between the presence of herpesviruses and most patients' characteristics. EBV positivity in colonic samples was correlated with delayed leukocyte and platelet recovery post-HSCT. Higher EBV frequency in the colonic mucosa was found in deceased patients (56% versus 21%, p = 0.02). The correlations among EBV positivity in the colon, lethality rates and delayed hematopoietic reconstitution suggest some relationship with systemic and local EBV reactivation post-transplant.

Extracorporeal Photopheresis in Children with Chronic Graft-Versus-Host Disease.

Chronic graft versus host disease (cGVHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). It significantly decreases survival and quality of life. The present study demonstrates retrospective data on extracorporeal photopheresis (ECP) in children with cGVHD. A total of 42 children with steroid-refractory cGVHD were enrolled in the study. The majority of patients had acute leukemia (n = 32, 76%). All patients received ECP as second (n = 18, 43%) or third (n = 24, 57%) line of therapy. Initial ECP schedule consisted of bimonthly regimen for two consecutive days with possibility of further tapering according to response. Any concurrent treatment administered before ECP could be continued if considered necessary. Complete response to ECP was registered in seven (17%) patients and partial response in 24 (57%). Overall response according to organ involvement was as follows: skin (n = 24, 75%), mucous membranes (n = 16, 73%), liver (n = 8, 80%), gut (n = 4, 80%), lungs (n = 2, 22%) and joints (n = 2, 67%). Five-year overall, progression-free and failure-free survival was 57%, 56% and 30%, respectively. Non-relapse mortality at 5 years was 14%. We didn't observe any clinically significant complications in children that could be attributed to the procedure. ECP remains important and safe treatment option in children with cGVHD.

Risk factors for outcome after allogeneic stem cell transplantation in patients with advanced phase CML.

Allogeneic hematopoietic stem-cell transplantation (HSCT) remains the only curative option for patients with advanced chronic myeloid leukemia (CML). However, outcome is dismal and of short follow-up. The objective of the study was to determine long-term outcome and risk factors in patients with a history of CML Blast Crisis (BC; n = 96) or accelerated phase (n = 51) transplanted between 1990 and 2018. At transplant, patients had a median age of 39 (range 7-76) years and were in ≥CP2 (n = 70), in AP (n = 40) or in BC (n = 37) with a diagnosis-HSCT interval of median 1.9 (range 0.3-24.4) years. Overall survival (OS) amounted 34% (95% CI 22-46) and progression-free survival (PFS) 26% (95% CI 16-36) at 15 years. Adverse risk factors for OS and PFS were low CD34+ count in the graft, donor age (>36 years) and BC. Cumulative incidence of Non-Relapse Mortality (NRM) was 28% (95% CI 18-38) and of relapse (RI) 43% (95% CI 33-53) at 15 years. PB-HSCT and HSCT after 2008 were favorable prognostic factors for NRM, while family donor and patient age >39 years were independently associated with higher RI. HSCT resulted in long-term OS in patients with advanced CML. OS was improved in non-BC patients, with donors ≤36 years and with higher CD34+ dose in the graft.

Allogeneic hematopoietic cell transplantation with cord blood versus mismatched unrelated donor with post-transplant cyclophosphamide in acute myeloid leukemia.

BACKGROUND: Allogeneic hematopoietic cell transplantation (allo-HCT) using a mismatched unrelated donor (MMUD) and cord blood transplantation (CBT) are valid alternatives for patients without a fully human leukocyte antigen (HLA)-matched donor. Here, we compared the allo-HCT outcomes of CBT versus single-allele-mismatched MMUD allo-HCT with post-transplant cyclophosphamide (PTCy) in acute myeloid leukemia. METHODS: Patients who underwent a first CBT without PTCy (N = 902) or allo-HCT from a (HLA 9/10) MMUD with PTCy (N = 280) were included in the study. A multivariate regression analysis was performed for the whole population. A matched-pair analysis was carried out by propensity score-based 1:1 matching of patients (177 pairs) with known cytogenetic risk. RESULTS: The incidence of grade II-IV and grade III-IV acute graft-versus-host disease (GVHD) at 6 months was 36% versus 32% (p = 0.07) and 15% versus 11% (p = 0.16) for CBT and MMUD cohorts, respectively. CBT was associated with a higher incidence of graft failure (11% vs. 4%, p < 0.01) and higher 2-year non-relapse mortality (NRM) (30% vs. 16%, p < 0.01) compared to MMUD. In the multivariate analysis, CBT was associated with a higher risk of, NRM (HR = 2.09, 95% CI 1.46-2.99, p < 0.0001), and relapse (HR = 1.35, 95% CI 1-1.83, p = 0.05), which resulted in worse leukemia-free survival (LFS) (HR = 1.68, 95% CI 1.34-2.12, p < 0.0001), overall survival (OS) (HR = 1.7, 95% CI 1.33-2.17, p < 0.0001), and GVHD-free, relapse-free survival (GRFS) (HR = 1.49, 95% CI 1.21-1.83, p < 0.0001) compared to MMUD. The risk of grade II-IV acute GVHD (p = 0.052) and chronic GVHD (p = 0.69) did not differ significantly between the cohorts. These results were confirmed in a matched-pair analysis. CONCLUSIONS: CBT was associated with lower LFS, OS, and GRFS due to higher NRM, compared to MMUD allo-HCT with PTCy. In the absence of a fully matched donor, 9/10 MMUD with PTCy may be preferred over CBT.

Immune checkpoints bone marrow expression as the predictor of clinical outcome in myelodysplastic syndrome.

AIMS: In our single-center retrospective study we evaluated whether level of different checkpoint molecules in bone marrow biopsies at diagnosis affect the clinical course of patients with myelodysplastic syndrome (MDS). METHODS AND RESULTS: A consecutive cohort of 55 MDS patients treated in our center from 2003 to 2018 with available bone marrow biopsies at time of diagnosis was studied. We used a technique able to detect the expression of the following antigens: PD-1, PD-L1, PD-L2, LAG-3, Gal-9, TIM-3, CD80. The association between expression level and 3-year overall and relapse-free survival and time-to-progression was analyzed. Intensive expression of TIM-3 was observed in 100% of cases. Also, in most cases, moderate Gal-9 expression was observed. With 3-year follow-up disease progression was seen in 72.9% of patients with high CD80 level and 52.1% of patients with low CD80 level (p=0.04). PD-1, CTLA4 and TIM-3 ligands were co-expressed in the majority of patients. General checkpoint ligand expression level also was associated with increased 3-year incidence of progression: 67.2% of patients with high level of checkpoint ligands progressed, while in the group with low checkpoint ligand expression level progression was observed only in 33.3% of cases (p=0.059). There was an association between the expression of checkpoint molecules CD80, PD-L2, TIM3, the number of bone marrow blasts and risk according to IPSS and IPSS-R scales. CONCLUSIONS: Our preliminary study underlined heterogeneous immune checkpoint molecules expression in MDS and warrants further studies to define the role of this heterogeneity and develop optimal treatment approaches.