Transfusion Support in Hematopoietic Stem Cell Transplantation: A Contemporary Narrative Review.

Hematopoietic stem cell transplantation (HSCT) is a cornerstone of modern medical practice, and can only be performed safely and effectively with appropriate transfusion medicine support. Patients undergoing HSCT often develop therapy-related cytopenia, necessitating differing blood product requirements in the pre-, peri-, and post-transplant periods. Moreover, ensuring optimal management for patients alloimmunized to human leukocyte antigens (HLA) and/or red blood cell (RBC) antigens, as well as for patients receiving ABO-incompatible transplants, requires close collaboration with transfusion medicine and blood bank professionals. Finally, as updated transfusion guidelines and novel blood product modifications emerge, the options available to the transplant practitioner continue to expand. Herein, we detail contemporary blood transfusion and transfusion medicine practices for patients undergoing HSCT.

Trends in Volumes and Survival After Hematopoietic Cell Transplantation in Racial/Ethnic Minorities.

There has been an increase in volume as well as improvement in overall survival (OS) after hematopoietic cell transplantation (HCT) for hematologic disorders. It is unknown if these changes have impacted racial/ethnic minorities equally. In this observational study from Center for International Blood and Marrow Transplant Research of 79,904 autologous (auto) and 65,662 allogeneic (allo) HCTs, we examined the volume and rates of change of auto HCT and allo HCT over time and trends in OS in 4 racial/ethnic groups: Non-Hispanic Whites (NHWs), Non-Hispanic African Americans (NHAAs), Hispanics across five 2-year cohorts from 2009 to 2018. Rates of change were compared using Poisson model. Adjusted and unadjusted Cox proportional hazards models examined trends in mortality in the 4 racial/ethnic groups over 5 study time periods. The rates of increase in volume were significantly higher for Hispanics and NHAAs vs. NHW for both autoHCT and alloHCT. Adjusted overall mortality after autoHCT was comparable across all racial/ethnic groups. NHAA adults (HR 1.13; 95% CI 1.04-1.22; p=0.004) and pediatric patients (HR 1.62; 95% CI 1.3-2.03; p<0.001 had a higher risk of mortality after alloHCT compared to NHWs. Improvement in OS over time was seen in all 4 groups after both autoHCT and alloHCT.Our study shows the rate of change for the use of autoHCT and alloHCT is higher in NHAAs and Hispanics compared to NHWs. Survival after autoHCT and alloHCT improved over time, however NHAAs have worse OS after alloHCT which has persisted. Continued efforts are needed to mitigate disparities for patients requiring alloHCT.

Harmonizing definitions for hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism in allogeneic hematopoietic cell transplantation: a report on behalf of the EBMT, ASTCT, CIBMTR, and APBMT.

Despite emergence of novel therapies to treat hematologic malignancies, allogeneic hematopoietic cell transplantation (allo-HCT) remains an essential treatment modality capable of curing these diseases. Allo-HCT has been also shown to be curative in benign hematologic disorders such as aplastic anemia, sickle cell disease, and thalassemia, among others. Recently, the American Society for Transplantation and Cellular Therapy (ASTCT) published standardized definitions for hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism. To attempt broader international consensus, a panel of adult and pediatric physician transplant experts was assembled from European Society for Blood and Marrow Transplantation (EBMT), ASTCT, the Center for International Blood and Marrow Transplant Research (CIBMTR), and Asia-Pacific Blood and Marrow Transplantation (APBMT). Consensus was defined as ≥70% of voting members strongly agreeing or somewhat agreeing with a definition. With few exceptions, there was a consensus to endorse the prior ASTCT definitions. Importantly, we revised existing EBMT and CIBMTR data collection forms to align with these harmonized definitions that will facilitate research and international collaboration among transplant researchers and across transplant registries.

Comparison of fludarabine/melphalan (FluMel) with fludarabine/melphalan/BCNU or thiotepa (FBM/FTM) in patients with AML in first complete remission undergoing allogeneic hematopoietic stem cell transplantation - a registry study on behalf of the EBMT Acute Leukemia Working Party.

Conditioning protocols for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) are being developed continuously to improve their anti-leukemic efficacy and reduce their toxicity. In this study, we compared the conditioning protocol of fludarabine with melphalan 140 mg/m2 (FluMel) with conditioning protocols based on this same backbone but with an additional alkylating agent i.e., either fludarabine/BCNU (also known as carmustine)/melphalan (FBM), or fludarabine/thiotepa/melphalan (FTM) 110 mg/m2. We included 1272 adult patients (FluMel, n = 1002; FBM/FTM, n = 270) with acute myeloid leukemia (AML) with intermediate/poor cytogenetic risk in first complete remission (CR) from the registry of the EBMT Acute Leukemia Working Party. Despite patients in the FBM/FTM group were older (64.1 years vs. 59.8 years, p < 0.001) and had a worse Karnofsky performance score (KPS < 90, 33% vs. 24%, p = 0.003), they showed a better overall survival (OS) (2 y OS: 68.3% vs. 58.1%, p = 0.02) and less non-relapse mortality (NRM) (2 y NRM: 15.8% vs. 22.2%, p = 0.009) compared to patients treated with FluMel. No significant differences were observed in relapse incidence (RI) (2 y RI: 24.9% vs. 23.7%, p = 0.62). In conclusion, the addition of a second alkylating agent (BCNU/carmustine or thiotepa) to FluMel as FBM/FTM conditioning, improves OS in AML patients in first CR with intermediate/poor risk cytogenetics after allo-HCT.

A simple prognostic system in patients with myelofibrosis undergoing allogeneic stem cell transplantation: a CIBMTR/EBMT analysis.

To develop a prognostic model for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) for myelofibrosis (MF), we examined the data of 623 patients undergoing allo-HCT between 2000 and 2016 in the United States (the Center for International Blood and Marrow Transplant Research [CIBMTR] cohort). A Cox multivariable model was used to identify factors prognostic of mortality. A weighted score using these factors was assigned to patients who received transplantation in Europe (the European Bone Marrow Transplant [EBMT] cohort; n = 623). Patient age >50 years (hazard ratio [HR], 1.39; 95% confidence interval [CI], 0.98-1.96), and HLA-matched unrelated donor (HR, 1.29; 95% CI, 0.98-1.7) were associated with an increased hazard of death and were assigned 1 point. Hemoglobin levels <100 g/L at time of transplantation (HR, 1.63; 95% CI, 1.2-2.19) and a mismatched unrelated donor (HR, 1.78; 95% CI, 1.25-2.52) were assigned 2 points. The 3-year overall survival (OS) in patients with a low (1-2 points), intermediate (3-4 points), and high score (5 points) were 69% (95% CI, 61-76), 51% (95% CI, 46-56.4), and 34% (95% CI, 21-49), respectively (P < .001). Increasing score was predictive of increased transplant-related mortality (TRM; P = .0017) but not of relapse (P = .12). The derived score was predictive of OS (P < .001) and TRM (P = .002) but not of relapse (P = .17) in the EBMT cohort as well. The proposed system was prognostic of survival in 2 large cohorts, CIBMTR and EBMT, and can easily be applied by clinicians consulting patients with MF about the transplantation outcomes.

Fludarabine/TBI 8 Gy versus fludarabine/treosulfan conditioning in patients with AML in first complete remission: a study from the Acute Leukemia Working Party of the EBMT.

The optimal reduced intensity conditioning (RIC) regimen is a matter of debate. We retrospectively compared conditioning with fludarabine plus fractionated total body irradiation of 8 Gy (FluTBI) and fludarabine plus treosulfan 30, 36 or 42 g/m2 (FluTreo) in 754 patients with AML above the age of 40 years undergoing an allogeneic hematopoietic stem cell transplant (HSCT) in first complete remission (CR). After balancing patient characteristics by propensity score matching of 115 patients in each group, FluTBI was associated with a significantly lower probability of relapse compared to FluTreo (18.3% vs. 34.7%, p = 0.018) which was counteracted by a higher non-relapse mortality (NRM, 16.8% vs. 5.3%, p = 0.02). Thus, overall survival and graft-versus-host disease-free and relapse-free survival at 2 years were similar between groups (OS 66.9% vs. 67.8%, GRFS 50.3% vs. 45.6%). Univariate analysis by age group demonstrated a higher NRM exclusively in patients ≥55 years of age treated with FluTBI compared to FluTreo (27.6% vs. 5.8%, p = 0.02), while a similarly low NRM was observed in patients <55 years in both groups (6.0% vs. 4.7%, p = ns). We conclude that both conditioning regimens are effective and safe, but FluTBI may better be reserved for younger patients below the age of 55 years.

Impact of measurable residual disease on outcomes of unrelated donor haematopoietic cell transplantation with post-transplant cyclophosphamide in AML in first complete remission.

Pre-transplant measurable residual disease (MRD) predicts relapse and outcome of allogeneic haematopoietic cell transplantation (allo-HCT). The impact of MRD on the outcomes of post-transplant cyclophosphamide (PTCy)-based allo-HCT from a matched unrelated donor (UD) is unknown. This study assessed the impact of MRD in acute myeloid leukaemia (AML) in the first complete remission (CR1). A total of 272 patients (MRD negative [MRD-], n = 165; MRD positive [MRD+], n = 107) with a median follow-up of 19 (range: 16-24) months were studied. The incidence of grades II-IV and grades III-IV acute GVHD at day 180 was 25.2% and 25% (p = 0.99), and 10.6% and 6.8% (p = 0.29), respectively, and 2-year chronic GVHD was 35% and 30.4% (p = 0.96) in MRD+ and MRD- cohorts, respectively. In multivariate analysis, MRD+ status was associated with a higher incidence of relapse (RI) (hazard ratio [HR] = 2.56, 95% CI: 1.39-4.72), lower leukaemia-free survival (LFS) (HR = 2.04, 95% CI: 1.23-3.39), overall survival (OS) (HR = 1.83, 95% CI: 1.04-3.25) and GVHD-free, relapse-free survival (GRFS) (HR = 1.69, 95% CI: 1.10-2.58). MRD status did not have a significant impact on non-relapse mortality (NRM), or acute or chronic GVHD risk. Among patients with AML undergoing UD allo-HCT with PTCy, pre-transplant MRD+ status predicted a higher relapse rate, lower LFS, OS and GRFS.

Association between the choice of the conditioning regimen and outcomes of allogeneic hematopoietic cell transplantation for myelofibrosis.

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative treatment for myelofibrosis. However, the optimal conditioning regimen either with reduced-intensity conditioning (RIC) or myeloablative conditioning (MAC) is not well known. Using the Center for International Blood and Marrow Transplant Research database, we identified adults aged ≥18 years with myelofibrosis undergoing allo-HCT between 2008-2019 and analyzed the outcomes separately in the RIC and MAC cohorts based on the conditioning regimens used. Among 872 eligible patients, 493 underwent allo-HCT using RIC (fludarabine/ busulfan n=166, fludarabine/melphalan n=327) and 379 using MAC (fludarabine/busulfan n=247, busulfan/cyclophosphamide n=132). In multivariable analysis with RIC, fludarabine/melphalan was associated with inferior overall survival (hazard ratio [HR]=1.80; 95% confidenec interval [CI]: 1.15-2.81; P=0.009), higher early non-relapse mortality (HR=1.81; 95% CI: 1.12-2.91; P=0.01) and higher acute graft-versus-host disease (GvHD) (grade 2-4 HR=1.45; 95% CI: 1.03-2.03; P=0.03; grade 3-4 HR=2.21; 95%CI: 1.28-3.83; P=0.004) compared to fludarabine/busulfan. In the MAC setting, busulfan/cyclophosphamide was associated with a higher acute GvHD (grade 2-4 HR=2.33; 95% CI: 1.67-3.25; P<0.001; grade 3-4 HR=2.31; 95% CI: 1.52-3.52; P<0.001) and inferior GvHD-free relapse-free survival (GRFS) (HR=1.94; 95% CI: 1.49-2.53; P<0.001) as compared to fludarabine/busulfan. Hence, our study suggests that fludarabine/busulfan is associated with better outcomes in RIC (better overall survival, lower early non-relapse mortality, lower acute GvHD) and MAC (lower acute GvHD and better GRFS) in myelofibrosis.

Fludarabine or cyclophosphamide in combination with total body irradiation as myeloablative conditioning prior to allogeneic hematopoietic cell transplantation for acute lymphoblastic leukemia: an analysis by the Acute Leukemia Working Party of the EBMT.

In this registry-based study we retrospectively compared outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) for adult patients with acute lymphoblastic leukemia (ALL) following conditioning with total body irradiation (TBI) combined with either cyclophosphamide (Cy) or fludarabine (Flu). TBI 12 Gy + Cy was used in 2105 cases while TBI 12 Gy + Flu was administered to 150 patients in first or second complete remission. In a multivariate model adjusted for other prognostic factors, TBI/Cy conditioning was associated with a reduced risk of relapse (HR = 0.69, p = 0.049) and increased risk of grade 2-4 acute graft-versus-host disease (GVHD, HR = 1.57, p = 0.03) without significant effect on other transplantation outcomes. In a matched-pair analysis the use of TBI/Cy as compared to TBI/Flu was associated with a significantly reduced rate of relapse (18% vs. 30% at 2 years, p = 0.015) without significant effect on non-relapse mortality, GVHD and survival. We conclude that the use of myeloablative TBI/Cy as conditioning prior to allo-HCT for adult patients with ALL in complete remission is associated with lower risk of relapse rate compared to TBI/Flu and therefore should probably be considered a preferable regimen.

Relapsed or refractory large B-cell lymphoma after chimeric antigen receptor T-cell therapy: Current challenges and therapeutic options.

Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy can provide durable remission in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) after failure of chemoimmunotherapy. However, patients who are refractory or relapsing after CAR-T therapy have poor outcomes. Multiple mechanisms of CAR-T therapy failure have been proposed but management of these patients remains a challenge. As CAR-T therapy moves earlier in the treatment of DLBCL, we urgently need trials focused on patients with relapse after CAR-T therapy. Recent advances in novel immunotherapies such as bispecific antibodies, antibody-drug conjugates and next-generation CAR-T therapies may provide avenues for treatment. Here we review the available data on using these drugs after failure of CAR-T therapy and provide a framework for the ideal sequencing of these novel agents.

Health-Related Quality of Life Outcomes in Older Hematopoietic Cell Transplantation Survivors.

The use of hematopoietic cell transplantation (HCT) has been increasing in older patients. However, the levels if distress, psychosocial functioning, and health-related quality of life (HRQOL) among older HCT survivors remains largely unknown. In this secondary analysis using data from 2 randomized controlled trials, we analyzed baseline Cancer and Treatment Distress (CTXD) and Confidence In Survivorship Information (CSI) surveys of HCT survivors who were age ≥60 years at the time of transplantation and alive and disease-free ≥1 year post-autologous or -allogeneic HCT. We analyzed associations of these parameters with the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores of the 12-Item Short Form Survey (SF-12) and a healthcare adherence (HCA) scale, after adjusting for transplantation and patient demographic factors. A total of 567 patients were included. The median patient age at HCT was 65 years, and 68% of the patients underwent autologous HCT. The median CTXD score was .7 (mild), and the greatest distress was reported in the "health burden" subscale. The median CSI score was 1.4 (moderate-high), with the lowest confidence reported in the "late effects" subscale. We found negative Spearman correlations between CTXD score and SF-12 PCS (P = -.59) and MCS (P = -.54) and positive Spearman correlations between CSI score and SF-12 PCS (P = .23) and MCS (P = .30). The median HCA scale score was high at .8. Male sex, autologous HCT, increased distress level, and worse CSI score were associated with lower use of preventive care. Older survivors experienced a low level of distress and moderate-high level of CSI at ≥1 year post-HCT. As lower distress and higher CSI were associated with improved HRQOL and optimized preventive HCA, CTXD/CSI measures can be used to individualize the care of older adult HCT survivors.

Expanded HCT-CI Definitions Capture Comorbidity Better for Younger Patients of Allogeneic HCT for Nonmalignant Diseases.

Allogeneic hematopoietic cell transplantation (HCT) can cure many nonmalignant conditions, but concern for morbidity and mortality remains. To help physicians estimate patient-specific transplant mortality risk, the HCT comorbidity index (HCT-CI) is used. However, pediatric physicians use the HCT-CI less frequently than adult counterparts. We used the Center for International Blood and Marrow Transplant Research database to expand the HCT-CI comorbidity definitions to be more inclusive of children and adolescent and young adult (AYA) patients, adding history of mechanical ventilation, history of invasive fungal infection, assessment of chronic kidney disease (CKD) by estimated glomerular filtration rate, expanding the definition of obesity, and adding an underweight category. A total of 2815 children and AYAs (<40 years old) who received first allogeneic HCT for nonmalignant diseases from 2008 to 2017 were included to create an expanded youth nonmalignant HCT-CI (expanded ynHCT-CI) and a simplified non-malignant (simplified ynHCT-CI) HCT-CI. The expanded comorbidities occurred frequently-history of mechanical ventilation (9.6%), history of invasive fungal infection (5.9%), mild CKD (12.2%), moderate/severe CKD (2.1%), obesity (10.9%), and underweight (14.5%). Thirty-nine percent of patients had an increase in their comorbidity score using the expanded ynHCT-CI, leading to a redistribution of scores: ynHCT-CI score 0 (35%), 1-2 (36.4%), and ≥3 (28.6%). Patients with an increase in their comorbidity score had an increased hazard of mortality compared to those whose score remained the same (hazard ratio = 1.41; 95% confidence interval, 1.01-1.98). Modifications to the HCT-CI can benefit children and AYA patients with nonmalignant diseases, creating a risk assessment tool that is clinically relevant and better captures comorbidity in this younger population.

Adapting the HCT-CI Definitions for Children, Adolescents, and Young Adults with Hematologic Malignancies Undergoing Allogeneic Hematopoietic Cell Transplantation.

Allogeneic hematopoietic cell transplantation is a curative procedure for hematologic malignancies but is associated with a significant risk of non-relapse mortality (NRM). The Hematopoietic Cell Transplantation-Comorbidity Index (HCT-CI) is a prognostic tool that discriminates this risk in all age groups. A recent survey of transplant physicians demonstrated that 79% of pediatric providers used the HCT-CI infrequently, and most reported concerns about its applicability in the younger population. We conducted a retrospective study using the Center for International Blood and Marrow Transplant Research database to examine the impact of expanded HCT-CI definitions on NRM in pediatric and young adult patients with hematologic malignancies. We included 5790 patients <40 years old receiving allogeneic transplants between 2008 and 2017 to examine broader definitions of comorbidities in the HCT-CI, including history of mechanical ventilation and fungal infection, estimated glomerular filtration rate, and body mass index (BMI) percentiles. Multivariable Fine-Gray models were created to determine the effect of each HCT-CI defining comorbidity and its modification on NRM and were used to develop 2 novel risk scores. We next developed the expanded HCT-CI for children and young adults (youth with malignancies; expanded ymHCT-CI), where 23% patients had an increased comorbidity score, compared to the HCT-CI. Comorbidities with hazard ratio < 1.2 were then removed to create the simplified HCT-CI for children and young adults (youth with malignancies; simplified ymHCT-CI), which demonstrated higher scores corresponded to a greater risk of NRM (P < .001). These novel comorbidity indexes with broader definitions are more relevant to pediatric and young adult patients, and prospective studies are needed to validate these in the younger patient population. It remains to be seen whether the development of these pediatric-specific and practical risk indexes increases their use by the pediatric transplant community.

American Society for Transplantation and Cellular Therapy Return to Work Guidance Committee Recommendations for Health Care Providers Who Take Care of Hematopoietic Cell Transplantation Patients.

Hematopoietic cell transplantation (HCT) health care providers report a desire to improve long-term outcomes and quality of life for their patients. One of the items frequently cited by patients in terms of transitioning from being a patient back to pre-HCT life is return to work (RTW). However, these patients report little support from their health care providers in facilitating this process, and only 50% to 60% achieve RTW, at a median of 3 years post-HCT. Barriers are physical, psychological, and logistical, as well as poor communication between the patient and their employer. We convened a group of experts in survivorship, rehabilitation, social work, and psychology to draft an evidence-based document to assist health care providers in guiding their patients' RTW journey. Guidance is drawn from the existing literature for HCT and general cancer patients and is divided into pre-HCT, peri-HCT, and post-HCT categories. Collaboration among health care providers, patients, and their employers is key to this transition. Suggested referrals and evaluations also are provided. The goal is for this guidance to be continually updated as we advance the field with more HCT-specific literature.

Irradiation-free, T-cell replete haploidentical transplant for Fanconi anaemia, weighing the benefits.

The optimal haploidentical haematopoietic cell transplant approach for Fanconi anaemia (FA) patients is not well established, given the rarity of the disease, the increased sensitivity to DNA-damaging agents and the high risk of severe graft-versus-host disease (GVHD). The report by Xu et al. suggests that excellent engraftment and short-term survival can be achieved in FA patients without irradiation, but their retrospective cohort was plagued by a high rate of severe GVHD. Our commentary explores the outcomes in T-cell replete haploidentical haematopoietic cell transplant and ponders whether elimination of total body irradiation in FA patients is the best method if it limits the ability to safely administer post-transplant cyclophosphamide. Commentary on: Xu et al. Unmanipulated haploidentical haematopoietic cell transplantation with radiation-free conditioning in Fanconi anaemia: A retrospective analysis from the Chinese Blood and Marrow Transplantation Registry Group. Br J Haematol. 2022;199:401-410.

Impact of Cytogenetic Risk on Outcomes of Non-T-Cell-Depleted Haploidentical Hematopoietic Cell Transplantation in Patients with Relapsed or Refractory Acute Myeloid Leukemia.

Baseline cytogenetics and disease status are key factors predicting the outcomes of allogeneic hematopoietic cell transplantation (HCT) in patients with acute myeloid leukemia (AML). The importance of cytogenetic risk in patients with primary refractory or relapsed (R/R) AML undergoing haploidentical (Haplo) HCT is unknown. We studied the impact of cytogenetic risk in patients with R/R de novo AML with active disease who underwent non-T-cell-depleted Haplo-HCT with post-transplantation cyclophosphamide from 2010 to 2020. Four hundred forty patients with active disease at transplantation from the European Society for Blood and Marrow Transplantation database were analyzed (291 [66.1%] with intermediate-risk [AMLint] and 149 [44.1%] with adverse-risk cytogenetics [AMLadv]). Impact of baseline cytogenetic risk on various transplantation outcomes was evaluated. Pre-transplantation disease status was relapse in 48.1% and 26.8% and primary refractory in 51.9% and 73.2% of the patients with AMLint and AMLadv, respectively (P < .0001). Two-year leukemia-free survival (LFS, 35.5% versus 15.5%, P = .001) and overall survival (OS, 39.2% versus 20.1%, P = .001) were better in AMLint versus AMLadv. In multivariate analysis, the relapse rate was significantly higher (hazard ratio [HR] = 2.17 [95% confidence interval {CI} 1.57-3.0]) and LFS (HR = 1.71 [95% CI, 1.31-2.22]) and OS (HR = 1.69 [95% CI, 1.29-2.22]), significantly lower for patients with AMLadv compared to AMLint, conditioning intensity did not affect leukemia relapse rate. Non-relapse mortality (HR = 1.1 [95% CI, 0.7-1.74]) and graft-versus-host disease-free, relapse-free survival (HR = 1.37 [95% CI, 1.06-1.77]) did not differ significantly between the risk groups. Disease status before transplant (primary refractory versus relapsed) or conditioning intensity did not impact main transplant outcomes. Baseline cytogenetic risk remains a key prognostic factor for patients with R/R AML with persistent disease before non-T-cell-depleted Haplo-HCT.