Increased Epstein‒Barr virus reactivation following prophylaxis for cytomegalovirus infection after haploidentical haematopoietic stem cell transplantation.

Letermovir (LTV) prophylaxis is effective in reducing the incidence of clinically significant cytomegalovirus (CMV) infection (cs CMVi) after allogeneic haematopoietic stem cell transplantation (allo-HSCT). Since our centre began administering LTV prophylaxis in June 2022, we have observed a certain increase in the incidence of Epstein-Barr virus (EBV) reactivation after haploidentical HSCT. We retrospectively analysed 230 consecutive patients who underwent haploidentical HSCT with rabbit anti-thymocyte globulin (ATG) from October 2022 to June 2023. The LTV group included 133 patients who received LTV prophylaxis, and the control group included 97 patients who did not receive LTV prophylaxis. At 1 year after HSCT, EBV reactivation was observed in 36 patients (27%) in the LTV group and 13 patients (13%) in the control group (p = 0.012). All patients with EBV reactivation had EBV-DNAemia, and one patient in each group developed EBV-associated posttransplantation lymphoproliferative disorder (PTLD). The proportion of patients with low EBV-DNA loads (> 5 × 102 to < 1 × 104 copies/mL) was greater in the LTV group than in the control group (23% vs. 10%, p = 0.01). The proportion of patients with CMV reactivation was lower in the LTV group than in the control group (35% vs. 56%, p = 0.002). There was no significant difference between the groups in terms of neutrophil and platelet count recovery, the cumulative incidence of acute/chronic graft-versus-host disease, overall survival, cumulative relapse rate or nonrelapse mortality. Our results show that the increased incidence of EBV reactivation may be associated with LTV prophylaxis for CMV after haploidentical HSCT.

Comparison of Three Graft-versus-Host Disease Prophylaxis Strategies after T Cell-Replete Haploidentical Hematopoietic Transplantation: Tacrolimus versus Calcineurin Inhibitors + Mycophenolate Mofetil versus Sirolimus + Mycophenolate Mofetil.

Since the introduction of post-transplantation cyclophosphamide (PTCy), haploidentical hematopoietic stem cell transplantation (haploSCT) has become a real alternative for patients who lack other eligible donors. The standard graft-versus-host disease (GVHD) prophylaxis after PTCy has been a calcineurin inhibitor (CNI) plus mycophenolate mofetil (MMF) (up to day +35), but promising results with sirolimus (with or without MMF) and single-agent tacrolimus have been published recently. This multicenter retrospective study compared the outcomes of 372 adult haploSCT recipients who received conditioning with thiotepa, busulfan, and fludarabine (TBF), PTCy, and additional GVHD prophylaxis with 1 of 3 strategies: cohort A, single-agent tacrolimus (n = 222); cohort B, CNI + MMF (n = 49); or cohort C, sirolimus + MMF (n = 101). No differences among the 3 cohorts were found in terms of grade II-IV acute GVHD (20% in cohort A, 25% in cohort B, and 30% in cohort C) or grade III-IV acute GVHD (9%, 6%, and 15%, respectively) at 100 days; however, cohort A had the lowest incidence of overall chronic GVHD (24%, 47%, and 52%, respectively; P = .001) and moderate-severe chronic GVHD (13%, 35%, and 33%, respectively; P = .001). There were no differences in 3-year overall survival, progression-free survival, nonrelapse mortality, or relapse among the 3 cohorts. Overall, our study suggests that single-agent tacrolimus, CNI + MMF, and sirolimus + MMF GVHD prophylaxis lead to similar outcomes following haploSCT with TBF and PTCy, with a low incidence of grade III-IV acute GVHD, although possible differences in chronic GVHD require further investigation.

Haplo-cord transplant. Realizing the potential of umbilical cord blood grafts. - A review of techniques and analysis of outcomes.

The combination of cord blood transplant with progenitor cells from partially HLA-matched adult donors (haplo-cord transplant) has been used over the past two decades. In Europe and the US the adult donor graft is CD34 selected and provides early hematopoiesis, but durable engraftment derives from the cord blood graft (CD34 selected haplo-cord). Neutrophil recovery is prompt and rates of acute and chronic GVHD are low. Recent Chinese studies combine cord blood grafts with T-replete haplo-identical grafts (unmodified haplo-cord). The haplo graft usually establishes dominance and UCB chimerism is rarely detected. Comparison studies suggest considerably decreased rates of relapse and improved outcomes, compared with either haplo-identical transplant or CBU transplant, particularly in patients with advanced leukemia. A recent prospective randomized study confirms this. Haplo-cord mitigates the engraftment delay of UCB transplant. The unique biology of UCB grafts results in low GVHD and improved GVL especially beneficial in high-risk disease.

Clinical characteristics and outcomes of overt gastrointestinal bleeding in children undergoing haploidentical hematopoietic stem cell transplantation: a single-center retrospective analysis.

BACKGROUND: Overt gastrointestinal bleeding (GIB) is a potentially serious and life-threatening condition in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, relatively little information is available regarding overt GIB in children. OBJECTIVES: To assess the prevalence, clinical patterns, and outcomes of overt GIB in children undergoing haploidentical hematopoietic stem cell transplantation (haplo-HSCT). METHODS: A total of 123 consecutive patients with malignant or non-malignant blood disorders who received haplo-HSCT were reviewed in our hospital between October 2017 and October 2022. Overt GIB was determined as hematemesis, melena or hematochezia. Continuous variables were compared by Mann Whitney U test. Categorical parameters were compared by the χ2 test or Fisher's exact test. Kaplan-Meier curves and log-rank tests were used to assess overall survival (OS), non-relapse mortality (NRM) and relapse. Univariate and multivariate analyses were performed to identify potential risk factors of overt GIB development. RESULTS: The median follow-up was 26.3 (range,1.7-74.8) months. Overt GIB occurred in 31 patients (25.2% incidence), with a median time elapsed after haplo-HSCT of 376 days (range, 58-1275 days). Compared with the non-GIB group, patients with overt GIB had reduced OS and increased NRM. In multivariate analysis, grade III-IV gut acute graft versus-host disease (aGvHD), thrombotic microangiopathy (TMA) and cytomegalovirus (CMV) viremia were significant risk factors for the occurrence of overt GIB after haplo-HSCT. CONCLUSIONS: Overt GIB is a frequent complication after haplo-HSCT in pediatric patients, and associated with worse survival. Grade III-IV gut aGvHD, TMA and CMV viremia were associated with its development.

Encephalitozoon hellem infection after haploidentical allogeneic hematopoietic stem cell transplantation in children: a case report.

Background: Encephalitozoon hellem (E. hellem) infection is a zoonotic disease, rarely observed in individuals, causing various clinical manifestations including diarrhea, keratoconjunctivitis, cystitis, etc. E. hellem infection after hematopoietic stem-cell transplantation (HSCT) is a rare, serious complication. Case presentation: Herein, we present a case of E. hellem infection developing during HLA-haploidentical HSCT in a 9-year-old boy who suffered from aplastic anemia. On 15 days after HSCT, the patient developed recurrent and prolonged fever, diarrhea and hematuria. It is challenging to differentiate whether the symptoms mentioned in this case are caused by graft-versus-host disease (GVHD) or a specific infection. Based on the result of metagenomic next-generation sequencing (mNGS) and clinical observation, the patient was diagnosed as E. hellem infection, and received albendazole and decreased the immunosuppressive treatment. Finally, he had recovered. Conclusion: We should pay attention to the uncommon disease caused by the E. hellem infection after HSCT, especially in cases with immune reconstitution unrecovered. Among those rare infection, mNGS can be performed for better understanding the source of infection and targeted therapy, which can benefit the patients.

Reduced-toxicity conditioning regimen with low dose post-transplantation cyclophosphamide and low-dose anti-thymocyte globulin as graft-versus-host disease prophylaxis for haploidentical stem cell transplantation in older patients.

Reduced-toxicity conditioning (RIC) regimens are used for allogeneic hematopoietic stem cell transplantation in older patients. However, successful outcomes are hindered by graft-versus-host disease (GVHD), treatment-related mortality, and relapse, particularly after haploidentical donor hematopoietic stem cell transplantation (HID-HSCT). The aim of this study was to evaluate the effectiveness of an RIC conditioning regimen that included a combination of cyclosporin A, methotrexate (on day + 1), mycophenolate, lower doses of post-transplantation PTCy (40 mg/kg on day + 3), and ATG (7.5 mg/kg) as GVHD prophylaxis prior to haplo-stem cell transplantation (haplo-SCT) in older patients. METHODS: We retrospectively analyzed outcomes in 55 patients ≥ 55 years of age with hematologic malignancies treated with fludarabine, cytarabine, busulfan, and low-dose cyclophosphamide as the conditioning regimen between January 1, 2019, and November 30, 2023. RESULTS: Neutrophil engraftment was successful in all patients within 28 days, with 54 patients (98.2%) achieving complete donor chimerism. The cumulative incidence of non-relapse mortality was 0% at 30 days, 7.5% at 100 days, and 19% at 1 year. The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 25% (95%CI, 15-38%), whereas that of grade III-IV aGVHD was 9.1% (95% CI, 3.3-19%). The cumulative incidence of extensive chronic graft-versus-host disease at 1 year was 3.6% (95%CI, 0.66-11%). The cumulative incidences of relapse, overall survival, and GVHD-free/relapse-free survival at 1 year were 9.0%, 71.6%, and 67.1%, respectively. CONCLUSIONS: An RIC conditioning regimen, including a combination of lower PTCy/ATG as GVHD prophylaxis, followed by haplo-SCT, might be a promising option for appropriately selected older patients.

Haploidentical hematopoietic cell transplantation with or without an unrelated cord blood unit for adult acute myeloid leukemia: a multicenter, randomized, open-label, phase 3 trial.

Coinfusion of unrelated cord blood (UCB) units in haploidentical hematopoietic cell transplantation (haplo-HCT) (haplo-cord HCT) for hematopoietic malignancies showed promising results in previous reports, but the efficiency of haplo-cord HCT in acute myeloid leukemia (AML) still lacks sufficient evidence. This multicenter, randomized, phase 3 trial (ClinicalTrials.gov NCT03719534) aimed to assess the efficacy and safety of haplo-cord HCT in AML patients. A total of 268 eligible patients aged 18-60 years, diagnosed with measurable residual disease in AML (excluding acute promyelocytic leukemia), with available haploidentical donors and suitable for allotransplantation, were randomly allocated (1:1) to receive haplo-cord HCT (n = 134) or haplo-HCT (n = 134). The 3-year overall survival (OS) was the primary endpoint in this study. Overall median follow-up was 36.50 months (IQR 24.75-46.50). The 3-year OS of Haplo-cord HCT group was better than haplo-HCT group (80.5%, 95% confidence interval [CI]: 73.7-87.9 vs. 67.8% 95% CI 60.0-76.5, p = 0.013). Favorable progression-free survival (70.3%, 95% CI 62.6-78.8 vs. 57.6%, 95% CI 49.6-67.0, p = 0.012) and cumulative incidence of relapse (12.1%, 95% CI 12.0-12.2 vs. 30.3%, 95% CI 30.1-30.4, p = 0.024) were observed in haplo-cord HCT group. Grade 3-4 adverse events (AEs) within two years posttransplantation in the two groups were similar. Haplo-cord HCT patients exhibited a faster cumulative incidence of neutrophil recovery (p = 0.026) and increased T-cell reconstitution in the early period posttransplantation. Haplo-cord HCT can improve OS in AML patients without excessive AEs, which may exert additional benefits for recipients of haplo-HCT.

Characterization of Chronic Graft-versus-host Disease After Haploidentical Stem Cell Transplantation With Posttransplant Cyclophosphamide: A Study on Behalf of GETH-TC.

BACKGROUND: Chronic graft-versus-host disease (cGVHD) is a cause of late morbidity and nonrelapse mortality (NRM) after allogenic hematopoietic stem cell transplantation (allo-HSCT). Although studies evaluating haploidentical allo-HSCT (haplo-HSCT) using posttransplant cyclophosphamide (PTCy) demonstrate lower cGVHD rates, comprehensive data describing the clinical profile, risk factors, or outcomes of cGVHD within this platform are scarce. METHODS: We conducted a retrospective multicenter analysis of 389 consecutive patients who underwent haplo-HSCT PTCy in 7 transplant centers of the Spanish Group Grupo Español de Trasplante Hematopoyético y Terapia Celular (GETH-TC) between 2008 and 2020 describing incidence, clinical profile, risk factors, and cGVHD outcomes. RESULTS: Ninety-five patients of 389 developed cGVHD. Our data revealed that the incidence and severity of cGVHD are lower than those reported for HLA-identical transplantation with conventional prophylaxis and that the strongest predictor for cGVHD was previous acute GVHD ( P  = 0.031). Also, recipient age ≥60 y ( P  = 0.044) was protective against cGVHD. Moreover, patients with moderate cGVHD had longer event-free survival at 3 y than other patients ( P  = 0.016) and a lower relapse rate at 3 y ( P  = 0.036). CONCLUSIONS: Our results support the fact that the incidence and severity of cGVHD are lower than those reported for HLA-identical transplantation with conventional prophylaxis. In this series, patients who develop moderate cGVHD after haplo-HSCT PTCy had a higher overall survival and event-free survival, and lower relapse, suggesting higher graft-versus-leukemia effect. Although this is the largest series focused on characterizing cGVHD in haplo-HSCT PTCy, further prospective studies are needed to confirm the findings.

Haploidentical and matched unrelated donor allogeneic hematopoietic stem cell transplantation offer similar survival outcomes for acute leukemia.

BACKGROUND: Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has emerged as an effective approach for acute leukemia, primarily due to the inherent difficulty in finding human leukocyte antigen-matched unrelated donors (MUD). Nevertheless, it remains uncertain whether haplo-HSCT and MUD-HSCT can provide comparable outcomes in patients with acute leukemia. AIMS: This study aimed to assess the overall survival (OS) and leukemia-free survival (LFS) outcomes between the MUD-HSCT and haplo-HSCT groups. METHODS AND RESULTS: This retrospective analysis encompassed adult patients with acute leukemia undergoing the initial allo-HSCT. Among these 85 patients, we stratified 33 patients into the MUD-HSCT group and 52 to the haplo-HSCT group. The primary outcomes were OS and LFS. The median OS was not reached in the haplo-HSCT group, while it reached 29.8 months in patients undergoing MUD-HSCT (p = .211). Likewise, the median LFS periods were 52.6 months in the haplo-HSCT group and 12.7 months in the MUD-HSCT group (p = .212). Importantly, neither the OS nor LFS showed substantial differences between the MUD-HSCT and haplo-HSCT groups. Furthermore, univariate analyses revealed that haplo-HSCT did not demonstrate a significantly higher risk of worse LFS (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.38-1.25; p = .216) or OS (HR, 0.67; 95% CI, 0.36-1.26; p = .214) than MUD-HSCT. Notably, a high European Group for Blood and Marrow Transplantation risk score (HR, 1.44; 95% CI, 1.10-1.87; p = .007) and non-complete remission (HR, 2.48; 95% CI, 1.17-5.23; p = .017) were significantly correlated with worse OS. CONCLUSION: Haplo-HSCT may serve as an alternative to MUD-HSCT for the treatment of acute leukemia, offering similar survival outcomes.

[Clinical study of the efficacies of ruxolitinib plus low-dose PTCY for acute GVHD prevention after haploidentical transplantation in malignant hematological diseases].

Objective: To investigate and verify a novel acute graft versus host disease (aGVHD) prevention protocol in the context of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) . Methods: Patients who underwent haplo-HSCT in our center between January 2022 and December 2022 were included. All patients received reduced doses of cyclophosphamide, Rabbit anti-human tymoglobulin, ruxolitinib, methotrexate, cyclosporine, and MMF to prevent aGVHD. The transplantation outcomes, complications, and survival rate of all patients were investigated. Results: A total of 52 patients with haplo-HSCT were enrolled, 29 (55.8%) male and 23 (44.2%) female, with a median age of 28 (5-59) years. There were 25 cases of acute myeloid leukemia, 17 cases of acute lymphocyte leukemia, 6 cases of myelodysplastic syndrome, 2 cases of chronic myeloid leukemia and 2 cases of myeloproliferative neoplasms. 98.1% of patients had successful engraftment. The incidence of Ⅱ-Ⅳ aGVHD and Ⅲ-Ⅳ aGVHD was 19.2% (95% CI 8.2% -30.3% ) and 7.7% (95% CI 0.2% -15.2% ), respectively. No patients experienced severe gastrointestinal mucositis. The Epstein-Barr virus and CMV reactivation rates were 40.4% and 21.3%, respectively. 9.6% of patients relapsed during followup, with 1-year overall survival, progression-free survival, and non-relapse mortality rates of 86.5% (95% CI 76.9% -96.1% ), 78.8% (95% CI 67.4% -90.3% ) and 11.5% (95% CI 2.6% -20.5% ), respectively. Conclusion: Ruxolitinib combined with a low dose of PTCY is a safe and effective first-line aGVHD prevention strategy.

Cytomegalovirus Reactivations in Allogeneic Hematopoietic Stem Cell Transplantation from HLA-Matched and Haploidentical Donors with Post-Transplantation Cyclophosphamide.

Cytomegalovirus (CMV) reactivations cause significant morbidity in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (PTCy) is associated with an increased risk of CMV infections. Data are limited comparing HSCT with PTCy performed from matched sibling donors (MSDs), matched unrelated donors (MUDs), and haploidentical (Haplo) donors. In the present study, we aimed to characterize CMV reactivation and recurrence in patients with hematologic malignancies undergoing HSCT from MSD, MUD, and Haplo donors using PTCy as GVHD prophylaxis in the pre-letermovir era. We also analyzed risk factors of CMV reactivation, including GVHD as a time-dependent variable, on the incidence and mortality associated with CMV infections. We analyzed CMV reactivation in patients undergoing HSCT from 160 MSDs, 124 MUDs, and 82 Haplo donors from a single institution. Uniform GVHD prophylaxis with PTCy, sirolimus, and mycophenolate mofetil was given irrespective of donor type. Overall, 46% of patients had at least 1 CMV reactivation. The 1-year cumulative incidence of CMV infection was 39% for MSD, 44% for MUD, and 62% for Haplo donors (P < .001), with 96% of reactivations occurring before day +100. Multivariate analysis identified factors associated with the first CMV reactivation, including Haplo donor, positive recipient CMV serology, older patient age, and grade II-IV acute GVHD. The 1-year cumulative incidence of second reactivation from HSCT was 13%. Recipient CMV seropositivity, older patient age, and grade II-IV acute GVHD, but not type of donor, were identified as adverse factors for second CMV reactivation in multivariate analysis. The 1-year cumulative incidence of a third reactivation post HSCT was 4.4%. Ten cases of CMV disease were recorded, with no attributable deaths. Nevertheless, the risk for nonrelapse mortality was greater for patients who experienced CMV reactivation in multivariate time-dependent Cox model analysis. CMV reactivation is frequent in HSCT with PTCy in patients not receiving letermovir prophylaxis. Identified risk factors include the use of a Haplo donor, recipient CMV seropositivity, and grade II-IV acute GVHD. The prevalence of recurrent CMV reactivations is a noteworthy issue, especially after acute GVHD, warranting trials of secondary prophylaxis strategies.

Pretransplantation predictors of survival in nonremission acute myeloid leukemia treated with haploidentical transplantation using steroid-based GVHD prophylaxis.

Haploidentical hematopoietic cell transplantation (HCT) using glucocorticoids for acute graft-versus-host disease prophylaxis (GC-haplo) may become a curative treatment option for nonremission acute myeloid leukemia (AML). This retrospective study aimed to identify pre-HCT predictors of survival in a cohort of 97 nonremission AML treated with GC-haplo in Hyogo Medical University Hospital between 2010 and 2020. Relapse and primary induction failure included in 70 (72%) and 27 (28%) patients, respectively. Sixty-one patients (63%) had undergone previous HCT. Multivariate analysis revealed that ≤ 6 months' duration between first complete remission (CR1) and first relapse (Rel1) (CR1-Rel1 interval) (hazard ratio 2.11, 95% confidence interval [CI] 1.15-3.89, P = 0.016) and serum albumin before starting the conditioning treatment of ≤ 3.5 g/dL (hazard ratio 1.80, 95%CI 1.09-2.96, P = 0.022) as risk factors for overall survival. Among three groups categorized according to serum albumin and CR1-Rel1 interval, the best 3-year overall survival was observed in patients with albumin > 3.5 g/dL and CR1-Rel1 interval > 6 months or primary induction failure (50.2%, 95%CI 28.9%-68.3%, P < 0.001), revealing that survival could be predicted using albumin and past CR duration in patients with very high-risk AML not in remission before GC-haplo.

HLA haploidentical stem cell transplantation from HLA homozygous donors to HLA heterozygous donors may have lower survival rates than haploidentical transplantation from HLA heterozygous donors to HLA heterozygous donors: a retrospective nationwide analysis.

In HLA haploidentical stem cell transplantation, patients and donors usually share one HLA haplotype and have one different HLA haplotype (hetero-to-hetero). However, there are rare cases of transplantation from HLA homozygous donors to heterozygous recipients (homo-to-hetero), resulting in mismatches only in the graft-versus-host direction. We previously reported that homo-to-hetero transplants have a lower survival rate in a mouse model than hetero-to-hetero transplants due to stronger graft-versus-host disease (GVHD) but inferior graft-versus-leukemia effect. To examine whether homo-to-hetero transplant effects also occur in humans, we retrospectively compared the results of 59 homo-to-hetero and 4,539 hetero-to-hetero cases in the Japanese transplant registry data. The results showed no statistical difference between the homo-to-hetero and hetero-to-hetero groups in the cumulative incidences of neutrophil engraftment (83.1% vs 89.0%), acute GVHD II-IV (36.8% vs 38.8%), III-IV (16.8% vs 17.4%), chronic GVHD (32.7% vs 30.7%), relapse (52.9% vs 49.0%), and non-relapse mortality (31.6% vs 28.2%). In contrast, overall survival was significantly lower in the homo-to-hetero group than in the hetero-to-hetero group (12.6% vs 26.2%, p = 0.0308). The inferior effect of homo-to-hetero transplantation on overall survival remained significant in multivariate analyses.

A retrospective analysis to evaluate if KIR B haplotype donors associate with a reduced risk of relapse in patients with haematological malignancies following haploidentical transplantation at the Blood and Bone Marrow Transplant Unit at Hammersmith Hospital ICHNHST.

Relapse is a major cause of treatment failure in haploidentical haematopoietic progenitor cell transplant (HPCT) with PTCy. Natural killer cells suppress graft versus host disease and mediate the graft versus leukaemia effect, driven by killer cell immunoglobulin-like receptors (KIRs). Emerging research suggests that donor KIR genotype may influence graft outcome in haploidentical transplants with varying impacts between patient cohorts. This study investigates whether donors with greater KIR B motifs associate with outcomes such as greater relapse-free survival (RFS), overall survival (OS), nonrelapse mortality (NRM), acute graft versus host disease (GvHD) and infection. The study cohort included 98 haploidentical donor-recipient (D/R) pairs (myeloablative n = 37, RIC n = 61) with various haematological malignancies, receiving primary T-cell replete haploidentical HSCT with PTCγ. Following KIR SSO genotyping, donors are categorised into neutral (n = 63) or better and best (n = 35), based on KIR B motif content. Kaplan-Meier and Cox regression survival functions are performed to investigate associations with outcomes. Our results show that the better and best category has significantly poorer RFS (p = 0.013; hazard ratio [HR] 3.16, 95% CI 1.21-8.24: p = 0.018). The greater risk of relapse associated with poorer OS (p = 0.011; HR 2.24, 95% CI 1.18-4.24: p = 0.01) in the better and best category. The competing KIR receptor-ligand and missing licensing proof models failed to predict transplant outcomes. Here, we show neutral donors associate with favourable outcomes in T-cell replete haplo-HPCT with PTCγ after categorisation using the KIR B content model, due to the increased risk of relapse associated with the use of better and best donors.

Low- versus standard-dose post-transplant cyclophosphamide as GVHD prophylaxis for haploidentical transplantation.

Haploidentical haematopoietic cell transplantation (haplo-HCT) using post-transplant cyclophosphamide (PTCY) as graft-versus-host disease (GVHD) prophylaxis is the standard of care for various haematological malignancies. The original PTCY dose after haplo-HCT was 100 mg/kg, but no dose-finding studies have been performed to identify the optimal dose. We performed a retrospective analysis to compare standard-dose PTCY (100 mg/kg) with reduced-dose PTCY (80 mg/kg): 969 in the standard-dose group and 538 in the reduced-dose group. As there was a significant difference between the two groups regarding patient and transplant characteristics, we performed propensity score (PS) matching. After PS matching, 425 patients in each group were included. The probabilities of 2-year OS were 55.9% in the standard-dose group and 47.0% in the reduced-dose group (p = 0.36). The cumulative incidences of 2-year non-relapse mortality were 21.3% in the standard-dose group and 20.5% in the reduced-dose group (p = 0.55). There was no significant difference in the incidence of acute (grade II-IV 29.2% [95% CI, 24.9-33.6] vs. 25.3% [95% CI, 21.3-29.6]; grade III-IV 7.3% [95% CI, 5.1-10.0] vs. 6.6% [95% CI, 4.5-9.3]) or chronic GVHD. In conclusion, reduced- and standard-dose PTCY were comparable in terms of major clinical outcomes.

TCRαß/CD19 cell-depleted HLA-haploidentical transplantation to treat pediatric acute leukemia: updated final analysis.

ABSTRACT: TCRαß/CD19 cell depletion is a promising graft manipulation technique frequently used in the context of human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (HSCT). We previously reported the results of a phase I-II clinical trial (NCT01810120) to assess the safety and the efficacy of this type of exvivo T-cell depletion in 80 children with acute leukemia, showing promising survival outcomes. We now report an updated analysis on a cohort of 213 children with a longer follow-up (median, 47.6 months for surviving patients). With a 5-year cumulative incidence of nonrelapse mortality of 5.2% (95% confidence interval [CI], 2.8%-8.8%) and a cumulative incidence of relapse of 22.7% (95% CI, 16.9%-29.2%), projected 10-year overall and disease-free survival (DFS) were 75.4% (95% CI, 68.6%-80.9%) and 71.6% (95% CI, 64.4%-77.6%), respectively. Cumulative incidence of both grade II-IV acute and chronic graft-versus-host disease were low (14.7% and 8.1%, respectively). In a multivariable analysis for DFS including type of disease, use of total body irradiation in the conditioning regimen (hazard ratio [HR], 0.5; 95% CI, 0.26-0.98; P = .04), disease status at HSCT (complete remission [CR] ≥3 vs CR 1/2; HR, 2.23; 95% CI, 1.20-4.16; P = .01), and high levels of pre-HSCT minimal residual disease (HR, 2.09; 95% CI, 1.01-4.33; P = .04) were independently associated with outcome. In summary, besides confirming the good outcome results already reported (which are almost superimposable on those of transplant from HLA-matched donors), this clinical update allows the identification of patients at higher risk of treatment failure for whom personalized approaches, aimed at reducing the risk of relapse, are warranted.

Meta-analysis of the results of haploidentical transplantation in the treatment of aplastic anemia.

This meta-analysis was to evaluate the outcome of haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) for aplastic anemia (AA) compared with matched related donor (MRD)-HSCT, matched unrelated donor (MUD)-HSCT, and immunosuppressive therapy (IST). Pubmed, Embase, Cochrane Library, Web of Science, CNKI, WanFang, and VIP databases were searched for relevant studies from inception to 22 June 2022. Relative risk (RR) was used to indicate the effect indicator, with a 95% confidence interval (CI) being applied to express the effect size. A subgroup analysis based on the literature quality (low, fair, and high) was applied. Totally, 25 studies were included in this study, comprising 2252 patients. Our findings demonstrated no difference between Haplo-HSCT and MRD-HSCT in 1-, 2-, and 3-year overall survival (OS), failure-free survival (FFS), and engraftment. However, Haplo-HSCT had higher incidences of II-IV acute graft-versus-host disease (aGVHD), chronic GVHD (cGVHD), and cytomegalovirus infection. There were no differences in 3- and 5-year OS, 3-year FFS, platelet engraftment, graft failure (GF), II-IV grade of aGVHD, and complication between Haplo-HSCT and MUD-HSCT; however, Haplo-HSCT had a lower incidence of cGVHD. Compared with IST, Haplo-HSCT had a higher 3-year FFS and 3- and 6-month response rate. However, there were no differences in 3- and 5-year OS, and 12-month response rate between Haplo-HSCT and IST. This study suggests that Haplo-HSCT may be a realistic therapeutic option for AA, which may provide a reference for decision-making.

Efficacy of letermovir in HLA-haploidentical hematopoietic transplantation with posttransplant cyclophosphamide.

BACKGROUND: Cytomegalovirus reactivation (CMV-R) is a significant complication of allogeneic hematopoietic stem cell transplantation (allo-HCT), especially in human leukocyte antigen-haploidentical transplantation (haplo-HCT) with posttransplant cyclophosphamide (PTCy). Prophylactic letermovir (LTV) prevents CMV-R in patients undergoing allo-HCT. However, evidence regarding its use in haplo-HCTs with PTCy is limited. Therefore, we aimed to investigate the efficacy of prophylactic LTV in haplo-HCT with PTCy. METHODS: We retrospectively analyzed 52 patients seropositive for CMV who underwent haplo-HCT with PTCy at our institution between January 2015 and June 2021 and compared patients who received LTV prophylaxis (LTV group: n = 29) with those who did not receive prophylaxis for CMV (control group: n = 23). The primary endpoint was the 100-day cumulative CMV-R incidence. We used Gray's test and the Fine and Gray test to compare the two groups. RESULTS: The 100-day cumulative CMV-R incidence was lower in the LTV group than in the control group (17.2% vs 81.8%, p < 0.001). Multivariate analysis revealed that prophylactic LTV reduced the 100-day cumulative CMV-R incidence (hazard ratio: 0.17, 95% confidence interval: 0.06-0.44, p < 0.001). CONCLUSIONS: Prophylactic LTV effectively prevents CMV-R in patients undergoing haplo-HCT for PTCy.

GVHD occurrence does not reduce AML relapse following PTCy-based haploidentical transplantation: a study from the ALWP of the EBMT.

The association between graft-versus-host disease (GVHD) occurrence and acute myeloid leukemia (AML) relapse in patients treated with HLA-haploidentical allogeneic hematopoietic stem cell transplantation (Haplo-HCT) with post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis has remained debated. Here, we addressed this issue in patients with active AML at transplantation. 2-year cumulative incidences of relapse and leukemia-free survival (LFS) were 49% and 32.3%, respectively. There were no associations between acute nor chronic GVHD of any grade and lower relapse incidence. However, grade I acute GVHD was associated with better LFS (HR = 0.71, 95% CI 0.51-0.99, P = 0.04). In contrast, grade III-IV acute (HR = 3.09, 95% CI 1.87-5.12, P < 0.0001) as well as extensive chronic (HR = 3.3, 95% CI 1.81-6.04, P = 0.0001) GVHD correlated with higher nonrelapse mortality leading to lower LFS (HR = 1.36, 95% CI 0.99-1.86, P = 0.056 and HR = 1.97, 95% CI 1.35-2.89, P = 0.0004, respectively). In conclusion, these data suggest a dissociation of graft-versus-leukemia effects from GVHD in patients with active AML treated with PTCy-based Haplo-HCT.