Red blood cell and platelet transfusion support in the first 30 and 100?days after allogeneic hematopoietic cell transplant
BACKGROUND Allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients often require substantial but variable transfusion support. STUDY DESIGN AND METHODS This single-center, retrospective study evaluated the red blood cell (RBC) and platelet (PLT) transfusion data of first-time allo-HSCT recipients transplanted in 2011 to 2017. Multivariate analyses were performed to assess the associations between patient and transplant-related factors and transfusion requirements. RESULTS The study included 1762 patients who received peripheral blood stem cells (88.2%), marrow (7.0%), or umbilical cord (4.8%) from matched related (38.3%), unrelated (49.2%), or haploidentical (7.8%) donors. Almost all patients required RBCs (88.3%) or PLTs (97.4%) during the first 30?days, with medians of 3 (range, 1-37) RBC and 6 (range, 1-144) PLT units transfused. Fewer patients required RBC (43.8%) or PLT (27.3%) transfusions during Days 31 to 100, but the median (range) numbers of RBC and PLT units remained high at 3 (1-36) and 6 (1-116) among transfused patients. RBC and PLT transfusion independence was reached in medians of 24 (95% confidence interval [CI], 22-26) and 12 (95% CI, 11-12) days, respectively. Haploidentical donor, cord graft, and requiring RBC transfusions in the 10?days before HSCT were the most significant independent factors predictive of increased transfusion requirements. Advanced disease, diagnosis, ABO incompatibility, conditioning intensity, CD34+ cell dose, presence of severe acute graft-vs-host disease, and changes in recommended transfusion triggers were also shown to independently impact transfusion requirements. CONCLUSIONS This study provided for the first time quantitative and comparative transfusion data on a large contemporary cohort of HSCT recipients, including haploidentical and cord graft recipients, and identified factors predictive of increased transfusions.
Comparing transplant outcomes in ALL patients after haploidentical with PTCy or matched unrelated donor transplantation
Blood advances. 2020;4(9):2073-2083
We compared outcomes of 1461 adult patients with acute lymphoblastic leukemia (ALL) receiving hematopoietic cell transplantation (HCT) from a haploidentical (n = 487) or matched unrelated donor (MUD; n = 974) between January 2005 and June 2018. Graft-versus-host disease (GVHD) prophylaxis was posttransplant cyclophosphamide (PTCy), calcineurin inhibitor (CNI), and mycophenolate mofetil (MMF) for haploidentical, and CNI with MMF or methotrexate with/without antithymoglobulin for MUDs. Haploidentical recipients were matched (1:2 ratio) with MUD controls for sex, conditioning intensity, disease stage, Philadelphia-chromosome status, and cytogenetic risk. In the myeloablative setting, day +28 neutrophil recovery was similar between haploidentical (87%) and MUD (88%) (P = .11). Corresponding rates after reduced-intensity conditioning (RIC) were 84% and 88% (P = .47). The 3-month incidence of grade II-IV acute GVHD (aGVHD) and 3-year chronic GVHD (cGVHD) was similar after haploidentical compared with MUD: myeloablative conditioning, 33% vs 34% (P = .46) for aGVHD and 29% vs 31% for cGVHD (P = .58); RIC, 31% vs 30% (P = .06) for aGVHD and 24% vs 29% for cGVHD (P = .86). Among patients receiving myeloablative regimens, 3-year probabilities of overall survival were 44% and 51% with haploidentical and MUD (P = .56). Corresponding rates after RIC were 43% and 42% (P = .6). In this large multicenter case-matched retrospective analysis, despite the limitations of a registry-based study (ie, unavailability of key elements such as minimal residual disease testing), our analysis indicated that outcomes of patients with ALL undergoing HCT from a haploidentical donor were comparable with 8 of 8 MUD transplantations.
What is known?
Allogeneic stem cell transplant is a potentially curative treatment option for adults with acute lymphoblastic leukaemia (ALL). Transplant outcomes are, amongst other factors, dependent on optimal donor selection; despite a plethora of recent advances, donor availability is an area of unmet need for many patients. A fully HLA matched sibling donor is the preferred donor choice but is available in <30% of patients. Several studies have shown that comparable results can be achieved with a fully matched unrelated donor (MUD), but availability can be as low as 20% in non-Caucasian individuals. Haploidentical donor options are available for the vast majority of patients but historically their utility was limited by high rates of GvHD, treatment related morbidity and mortality and graft rejection. The addition of post-transplant cyclophosphamide (PtCy), calcineurin inhibitors (CNI) and mycofenolate mofetil (MMF) as GvHD prophylaxis has reduced these risks and is now a frequently employed approach for haploidentical haematopoietic stem cell transplant (HaploSCT) making it an attractive alternative to conventional donor transplant.
Several recent studies have compared MUD alloSCT and HaploSCT approaches in ALL in recent years. Most notably this has included an analysis of the European Bone Marrow Transplant (EBMT) group registry which included 1234 patients with ALL and shows comparable outcomes between HaploSCT and MUD alloSCT.
What did this paper set out to examine?
This retrospective multicentre cohort study aims to compare outcomes of HaploSCT & PtCy with MUD alloSCT in ALL in terms of engraftment, acute and chronic graft versus host disease (GvHD) incidence and severity, relapse free survival (RFS), non-relapse mortality (NRM) and overall survival (OS).
It is the first study to explicitly compare haploidentical allogeneic stem cell transplant (HaploSCT) with matched unrelated donor allogeneic stem cell transplant (MUD alloSCT) in terms of conditioning intensity, Philadelphia chromosome status and graft source. It also provides additional extensive, multinational data with matched pair analysis on outcomes of patients in both groups.
What did they show?
The authors compared data from 1461 adult patients (HaploSCT = 487 vs MUD = 974). Data from two separate registries was used: the EBMT registry alone was used for MUD alloSCT while the Haploidentical Transplant and Cellular Therapy Research Consortium (TCT-RC) was used in combination with Acute Leukaemia Working Party subgroup of the EBMT registry data for assessment of HaploSCT. The reason for using two databases is not explicitly stated although it is believed that this was done to increase sample size in the HaploSCT cohort.
Patients >18 years old with ALL over a 13.5-year period from January 2005 to June 2018 receiving their first alloSCT were included in the analysis. Exclusion criteria were fairly selected. GvHD prophylaxis was with PtCy, CNI and MMF in the HaploSCT group and with CNI and methotrexate or MMF in the MUD group. 64% of MUD patients also received ATG. Cohorts were matched at 1:2 (HaploSCT : MUD) for sex, cytogenetic risk, Philadelphia chromosome status, disease stage and intensity of conditioning (reduced intensity vs myeloablative). Statistical analysis was appropriate for the question to be answered.
RESULTS: HaploSCT and MUD alloSCT were comparable in terms of neutrophil engraftment, RFS and OS regardless of conditioning intensity, Philadelphia chromosome status and graft source. 3-year OS was 44% in the HaploSCT group vs 51% in the MUD group using myeloablative conditioning (p=5.56) with rates of 43% (HaploSCT) and 42% (MUD) for reduced intensity conditioning (p=5.6).
The overall incidence of acute and chronic GvHD was similar between the groups but there was an increased incidence in grade III-IV GvHD in HaploSCT when peripheral blood stem cells were used. Additionally, mortality form GvHD was higher in the MUD group. This is in keeping with results reported in the literature.
What are the implications for practice and for future work?
HaploSCT is becoming an increasingly attractive option for patients without matched sibling transplant. The comparable overall survival and now much more manageable GvHD risk will afford a previously difficult to manage cohort of patients a further option of curative treatment.
This study adds to the growing evidence base but did have some limitations. Firstly, the study is retrospective and uses registry-based data. While the registries used are of high quality, there are inherent concerns about missing data points and differences between the two databases used. The authors agreed that the variability of the condition regimes used added a further layer of complexity.
Prospective data with intention to treat analysis is required to further assess the comparability of HaploSCT and MUD for ALL patients.
Adult patients with acute lymphoblastic leukaemia (n=1461)
HSCT from a haploidentical donor (n = 487)
HSCT from a matched unrelated donor (n = 974)
In the myeloablative setting, day +28 neutrophil recovery was similar between haploidentical (87%) and MUD (88%). Corresponding rates after reduced-intensity conditioning (RIC) were 84% and 88%. The 3-month incidence of grade II-IV acute GVHD (aGVHD) and 3-year chronic GVHD (cGVHD) was similar after haploidentical compared with MUD: myeloablative conditioning, 33% vs 34% for aGVHD and 29% vs 31% for cGVHD; RIC, 31% vs 30% for aGVHD and 24% vs 29% for cGVHD. Among patients receiving myeloablative regimens, 3-year probabilities of overall survival were 44% and 51% with haploidentical and MUD. Corresponding rates after RIC were 43% and 42%.
Poxvirus Vectored Cytomegalovirus Vaccine to Prevent Cytomegalovirus Viremia in Transplant Recipients: A Phase 2, Randomized Clinical Trial
Annals of internal medicine. 2020
Background: Triplex vaccine was developed to enhance cytomegalovirus (CMV)-specific T cells and prevent CMV reactivation early after hematopoietic stem cell transplant (HCT). Objective: To determine the safety and efficacy of Triplex. Design: First-in-patient, phase 2 trial. (ClinicalTrials.gov: NCT02506933). Setting: 3 U.S. HCT centers. Participants: 102 CMV-seropositive HCT recipients at high risk for CMV reactivation. Intervention: Intramuscular injections of Triplex or placebo were given on days 28 and 56 after HCT. Triplex is a recombinant attenuated poxvirus (modified vaccinia Ankara) expressing immunodominant CMV antigens. Measurements: The primary outcomes were CMV events (CMV DNA level ≥1250 IU/mL, CMV viremia requiring antiviral treatment, or end-organ disease), nonrelapse mortality, and severe (grade 3 or 4) graft-versus-host disease (GVHD), all evaluated through 100 days after HCT, and grade 3 or 4 adverse events (AEs) within 2 weeks after vaccination that were probably or definitely attributable to injection. Results: A total of 102 patients (51 per group) received the first vaccination, and 91 (89.2%) received both vaccinations (46 Triplex and 45 placebo). Reactivation of CMV occurred in 5 Triplex (9.8%) and 10 placebo (19.6%) recipients (hazard ratio, 0.46 [95% CI, 0.16 to 1.4]; P = 0.075). No Triplex recipient died of nonrelapse causes during the first 100 days or had serious AEs, and no grade 3 or 4 AEs related to vaccination were observed within 2 weeks after vaccination. Incidence of severe acute GVHD after injection was similar between groups (hazard ratio, 1.1 [CI, 0.53 to 2.4]; P = 0.23). Levels of long-lasting, pp65-specific T cells with effector memory phenotype were significantly higher in Triplex than placebo recipients. Limitation: The lower-than-expected incidence of CMV events in the placebo group reduced the power of the trial. Conclusion: No vaccine-associated safety concerns were identified. Triplex elicited and amplified CMV-specific immune responses, and fewer Triplex-vaccinated patients had CMV viremia. Primary Funding Source: National Cancer Institute and Helocyte.
CMV-seropositive HCT recipients at high risk for CMV reactivation (n=102)
Intramuscular injections of Triplex CMV vaccine (n=51)
Reactivation of CMV occurred in 5 Triplex (9.8%) and 10 placebo (19.6%) recipients (hazard ratio, 0.46). No Triplex recipient died of nonrelapse causes during the first 100 days or had serious AEs, and no grade 3 or 4 AEs related to vaccination were observed within 2 weeks after vaccination. Incidence of severe acute GVHD after injection was similar between groups (hazard ratio, 1.1). Levels of long-lasting, pp65-specific T cells with effector memory phenotype were significantly higher in Triplex than placebo recipients.
MIPSS70+ v2.0 predicts long-term survival in myelofibrosis after allogeneic HCT with the Flu/Mel conditioning regimen
Blood advances. 2019;3(1):83-95
Although allogeneic hematopoietic cell transplantation (allo-HCT) is the only curative treatment for myelofibrosis (MF), data are limited on how molecular markers predict transplantation outcomes. We retrospectively evaluated transplantation outcomes of 110 consecutive MF patients who underwent allo-HCT with a fludarabine/melphalan (Flu/Mel) conditioning regimen at our center and assessed the impact of molecular markers on outcomes based on a 72-gene next-generation sequencing panel and Mutation-Enhanced International Prognostic Scoring System 70+ v2.0 (MIPSS70+ v2.0). With a median follow-up of 63.7 months, the 5-year overall survival (OS) rate was 65% and the nonrelapse mortality (NRM) rate was 17%. In mutational analysis, JAK2 V617F and ASXL1 mutations were the most common. By univariable analysis, higher Dynamic International Prognostic Scoring System scores, unrelated donor type, and very-high-risk cytogenetics were significantly associated with lower OS. Only CBL mutations were significantly associated with lower OS (hazard ratio [HR], 2.64; P = .032) and increased NRM (HR, 3.68; P = .004) after allo-HCT, but CALR, ASXL1, and IDH mutations did not have an impact on transplantation outcomes. Patient classification per MIPSS70 showed worse OS for high-risk (HR, 0.49; P = .039) compared with intermediate-risk patients. Classification per MIPSS70+ v2.0 demonstrated better OS when intermediate-risk patients were compared with high-risk patients (HR, 0.291) and much lower OS when very-high-risk patients were compared with high-risk patients (HR, 5.05; P ≤ .001). In summary, we present one of the largest single-center experiences of Flu/Mel-based allo-HCT, demonstrating that revised cytogenetic changes and MIPSS70+ v2.0 score predict transplantation outcomes, and thus can better inform physicians and patients in making decisions about allo-HCT.
110 consecutive MF patients who underwent allo-HCT with a fludarabine/melphalan (Flu/Mel) conditioning regimen
Retrospective cohort study assessing the impact of molecular markers on outcomes based on a 72-gene next-generation sequencing panel and Mutation-Enhanced International Prognostic Scoring System
In the entire cohort, 5-year overall survival (OS) rate was 65% and the nonrelapse mortality (NRM) rate was 17%. Higher Dynamic International Prognostic Scoring System scores, unrelated donor type, and very-high-risk cytogenetics were significantly associated with lower OS. Only CBL mutations were significantly associated with lower OS. Patient classification per MIPSS70 showed worse OS for high-risk compared with intermediate-risk patients. Classification per MIPSS70+ v2.0 demonstrated better OS when intermediate-risk patients were compared with high-risk patients and much lower OS when very-high-risk patients were compared with high-risk patients.
Long term outcomes of patients with Acute Myeloid Leukemia treated with myeloablative FTBI based conditioning with Tacrolimus and sirolimus based GVHD prophylaxis regimen: 6 year follow up from Single Center
Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation. 2019
Cyclophosphamide/etoposide combined with fractionated total body irradiation (FTBI) or intravenous busulfan, has been the main conditioning regimens for allogeneic hematopoietic cell transplantation (alloHCT) for young patients with acute myeloid leukemia (AML) eligible for myeloablative conditioning regimens (MAC). Recent data has suggested that intravenous busulfan could be the preferred myeloablative regimen in patients with myeloid malignancies. However, busulfan-based regimens are associated with higher rates of sinusoidal obstruction syndrome. Here, we are reporting long-term survival outcomes of AML patients receiving FTBI combined with cyclophosphamide or etoposide before alloHCT at City of Hope. We obtained a retrospective review of a prospectively maintained institutional registry of clinical outcomes in 167 AML patients (median age =41 years, range: 18-57) in CR1/2, who underwent alloHCT from 2005-2015 at our center. Eligible patients received MAC with FTBI (1320 cGy) and cyclophosphamide (120 mg/kg) for unrelated donor (MUD) or etoposide (60 mg/kg) for related donors. Graft-versus-host disease (GVHD) prophylaxis was tacrolimus and sirolimus. In this retrospective study, 6-year overall survival was 60%, and non-relapse mortality was 15%. GRFS rate at 1 and 2 years was 45% and 39%, respectively. We also described late metabolic effects and cumulative incidence of secondary malignancies (9.5%) in this report. Overall, in this young adult patient population, our results compare favorably to chemotherapy- (intravenous Busulfan-) based conditioning regimens without significant long term toxicity arising from TBI-based regimen.
Long-term outcome of allogeneic hematopoietic stem cell transplantation from unrelated donor using tacrolimus/sirolimus-based GVHD prophylaxis: impact of HLA mismatch
BACKGROUND While Tacrolimus/Sirolimus (T/S)-based graft-versus-host disease (GvHD) prophylaxis has been effective in preventing acute GvHD post hematopoietic cell transplantation (HCT), its efficacy and long-term outcome in matched (MUD) and mismatched unrelated donor (mMUD) setting is not well defined. METHODS Herein, we evaluated a consecutive case-series of 482 patients who underwent unrelated donor (URD) HCT (2005 - 2013) with T/S-based GvHD prophylaxis. RESULTS With a median follow-up of 6.2 years (range=2.4-11.3), the 5-year overall survival (OS) and relapse/progression-free survival were 47.5% (95%CI: 43.0-52.0) and 43.6% (95%CI: 39.1-48.1), respectively; and the 5-year cumulative incidence of non relapse mortality (NRM) and relapse were 24.9%, and 31.5%, respectively. In this cohort, mMUD was associated with worse OS (39.0% vs. 50.7% at 5 years, p=0.034), primarily due to greater risk of NRM (33.5% vs. 21.7%, p=0.038). While rates of relapse, acute (II-IV or III-IV) or chronic GvHD (limited or extensive) were not different, death caused by chronic GvHD (20.8% vs. 12.8%, p=0.022) and infection (33.0% vs. 18.1%, p<0.01) were significantly greater in mMUD. In multivariable analysis, high-risk disease (HR= 2.21, 95%CI: 1.16-4.23; p<0.01) and mMUD (HR=1.55, 95%CI:.1.15-2.08; p=0.004) were independent predictive factors for OS. CONCLUSIONS T/S-based GvHD prophylaxis is an effective and acceptable GvHD prophylactic regimen. However, survival after mMUD remained poor, possibly related to the severity of chronic GvHD.
RBC and platelet transfusion support in the first 30 and 100 days after haploidentical hematopoietic stem cell transplantation
BACKGROUND The volume of haploidentical hematopoietic stem cell transplant (haplo-HSCT) has increased dramatically in recent years. However, the associated higher risk of delayed engraftment may increase patient transfusion requirements. STUDY DESIGN AND METHODS The post-HSCT RBC and platelet transfusions of 195 haplo-HSCT recipients were evaluated. Patient and transplant-related factors potentially impacting the number of products transfused and time to transfusion independence were assessed. RESULTS Nearly all (98.4%) patients were transfused in the first 30 days, and 59.2% were transfused between days 31 and 100. Among the transfused patients, medians of 5 units (interquartile range [IQR] = 3-8) of RBCs and 11 units (6-20) platelets were given in the first 30 days, and medians of 3 units (IQR = 1-7) of RBCs and 6 units (2-18) of platelets were transfused between days 31 and 100. Median times for achieving RBC and platelet transfusion independence were 34 (95% CI: 28-40) and 25 (95% CI: 23-27) days, respectively. Multivariable analyses showed that RBC transfusions in the 10 days before HSCT were associated with significantly increased and sustained RBC and platelet transfusion requirements. Major ABO incompatibility led to increased RBC transfusions. Advanced disease was associated with increased transfusions during the first 30 days, whereas GVHD increased platelet transfusions between days 31 and 100. Effects of age, sex, CD34+ cell dose, stem cell source, and conditioning regimen were limited or insignificant. CONCLUSIONS This study for the first time provided quantitative transfusion data on a large cohort of haplo-HSCT recipients and identified factors predictive of increased transfusions.
Myeloablative vs reduced intensity T-cell-replete haploidentical transplantation for hematologic malignancy
Blood advances. 2019;3(19):2836-2844
In the absence of prospective studies that examine the effect of conditioning regimen intensity after T-cell-replete haploidentical transplant for acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS), a retrospective cohort analysis was performed. Of the 1325 eligible patients (AML, n = 818; ALL, n = 286; and MDS, n = 221), 526 patients received a myeloablative regimen and 799 received a reduced-intensity regimen. Graft-versus-host disease prophylaxis was uniform with posttransplant cyclophosphamide, a calcineurin inhibitor, and mycophenolate mofetil. The primary end point was disease-free survival. Cox regression models were built to study the effect of conditioning regimen intensity on transplant outcomes. For patients aged 18 to 54 years, disease-free survival was lower (hazard ratio [HR], 1.34; 42% vs 51%; P = .007) and relapse was higher (HR, 1.51; 44% vs 33%; P = .001) with a reduced-intensity regimen compared with a myeloablative regimen. Nonrelapse mortality did not differ according to regimen intensity. For patients aged 55 to 70 years, disease-free survival (HR, 0.97; 37% vs 43%; P = .83) and relapse (HR, 1.32; 42% vs 31%; P = .11) did not differ according to regimen intensity. Nonrelapse mortality was lower with reduced-intensity regimens (HR, 0.64; 20% vs 31%; P = .02). Myeloablative regimens are preferred for AML, ALL, and MDS; reduced-intensity regimens should be reserved for those unable to tolerate myeloablation.
Patients with haematological malignancies (n=1325)
Myeloablative conditioning regimen (n=526)
Reduced-intensity conditioning regimen (n=799)
For patients aged 18 to 54 years, disease-free survival was lower and relapse was higher with a reduced-intensity regimen compared with a myeloablative regimen. Non-relapse mortality did not differ according to regimen intensity. For patients aged 55 to 70 years, disease-free survival and relapse did not differ according to regimen intensity. Nonrelapse mortality was lower with reduced-intensity regimens.
PTCy-based haploidentical vs matched related or unrelated donor reduced-intensity conditioning transplant for DLBCL
Blood advances. 2019;3(3):360-369
This study retrospectively compared long-term outcomes of nonmyeloablative/reduced intensity conditioning (NMC/RIC) allogeneic hematopoietic cell transplantation (allo-HCT) from a haploidentical family donor (haplo-HCT) using posttransplant cyclophosphamide (PTCy) with those of matched sibling donor (MSD) and matched unrelated donor (MUD) with or without T-cell depletion (TCD+/TCD-) in patients with relapsed diffuse large B-cell lymphoma (DLBCL). Adult patients with DLBCL who had undergone their first NMC/RIC allo-HCT between 2008 and 2015 were included. Recipients of haplo-HCT were limited to those receiving graft-versus-host disease (GVHD) prophylaxis with PTCy. GVHD prophylaxis in MSD was limited to calcineurin inhibitor (CNI)-based approaches without in vivo TCD, while MUD recipients received CNI-based prophylaxis with or without TCD. Outcome analyses for overall survival (OS) and progression-free survival (PFS), nonrelapse mortality (NRM), and disease relapse/progression were calculated. A total of 1438 patients (haplo, 132; MSD, 525; MUD TCD+, 403; and MUD TCD-, 378) were included. Patients with haplo donors were significantly older, had a better performance status and had more frequently received total body irradiation-based conditioning regimens and bone marrow grafts than MSD and MUD TCD+ or TCD-. 3-year OS, PFS, NRM and relapse/progression incidence after haplo-HCT was 46%, 38%, 22%, and 41%, respectively, and not significantly different from outcomes of matched donor transplants on multivariate analyses. Haplo-HCT was associated with a lower cumulative incidence of chronic GVHD compared with MSD, MUD TCD+/TCD-. NMC/RIC haplo-HCT with PTCy seems to be a valuable alternative for patients with DLBCL considered for allo-HCT but lacking a matched donor.
The European Society for Blood and Marrow Transplantation (EBMT) consensus recommendations for donor selection in haploidentical hematopoietic cell transplantation
Bone marrow transplantation. 2019
The number of HLA-haploidentical hematopoietic cell transplants continues to increase worldwide due to recent improvements in outcomes, allowing more patients with hematological malignancies and non-malignant disorders to benefit from this procedure and have a chance to cure their disease. Despite these encouraging results, questions remain as multiple donors are usually available for transplantation, and choosing the best HLA-haploidentical donor for transplantation remains a challenge. Several approaches to haploidentical transplantation have been developed over time and, based on the graft received, can be grouped as follows: T-cell depleted haploidentical transplants, either complete or partial, or with T-cell replete grafts, performed with post-transplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis, or G-CSF-primed bone marrow graft and enhanced GVHD prophylaxis. Carefully selecting the donor can help optimize transplant outcomes for recipients of haploidentical donor transplants. Variables usually considered in the donor selection include presence of donor-specific antibodies in the recipient, donor age, donor/recipient gender and ABO combinations, and immunogenic variables, such as natural killer cell alloreactivity or KIR haplotype. Here we provide a comprehensive review of available evidence for selecting haploidentical donors for transplantation, and summarize the recommendations from the European Society for Blood and Marrow Transplantation (EBMT) on donor selection for different transplant platforms.