Real-World Data Showing Trends and Outcomes by Race and Ethnicity in Allogeneic Hematopoietic Cell Transplantation: A Report from the Center for International Blood and Marrow Transplant Research

Post-Transplant Cyclophosphamide-Based Graft-Versus-Host Disease Prophylaxis Attenuates Disparity in Outcomes Between Use of Matched or Mismatched Unrelated Donors

PURPOSEAccess to allogeneic hematopoietic cell transplantation (HCT) remains limited among persons of non-European ancestry if human leukocyte antigen (HLA) matching is required. We evaluated whether post-transplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis improved HCT outcomes with HLA-matched unrelated donor (MUD) and mismatched unrelated donor (MMUD) HCT when compared with calcineurin inhibitor (CNI)-based prophylaxis.METHODSThree-year overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were compared between adult recipients undergoing initial MUD or single HLA locus MMUD HCT with either PTCy- or CNI-based prophylaxis who were reported to the Center for International Blood and Marrow Transplant Research between 2017 and 2021.RESULTSIncluded were 10,025 HCT recipients (7,272 recipients of MUD with CNI, 1,681 MUD with PTCy, 613 MMUD with CNI, and 459 MMUD with PTCy) who underwent HCT for acute leukemia (70.9%) or myelodysplastic syndromes (29.2%). Median patient age was 60.7 years (range, 18.0-82.7) and median follow-up was 36.6 (range, 3.0-77.8) months. When compared with MUD HCT with PTCy, MMUD HCT with PTCy had similar OS (hazard ratio [HR], 0.96 [95% CI, 0.823 to 1.11]; P = .60) and GRFS (HR, 0.90 [0.79 to 1.02]; P = .1). When compared with MUD HCT with CNI, OS was improved after MUD HCT with PTCy (HR, 0.88 [0.80 to 0.96]; P = .004) and GRFS was improved with PTCy after either MUD (HR, 0.61 [0.57 to 0.66]; P < .0001) or MMUD (HR, 0.68 [0.60 to 0.76]; P < .0001) HCT. Benefit from PTCy was independent of patient ancestry. Global registry level analysis demonstrated that inclusion of MMUD increased donor availability regardless of recipient ancestry.CONCLUSIONUse of PTCy results in comparable OS and GRFS using either MUD or MMUD HCT, expanding access to HCT for patients from all racial and ethnic ancestry groups.

Human Leukocyte Antigen Mismatching and Survival in Contemporary Hematopoietic Cell Transplantation for Hematologic Malignancies

PURPOSEHuman leukocyte antigen (HLA) mismatching can reduce survival of patients with blood cancer after hematopoietic cell transplantation (HCT). How recent advances in HCT practice, in particular graft-versus-host disease (GVHD) prophylaxis by post-transplantation cyclophosphamide (PTCy), influence HLA risk associations is unknown.PATIENTS AND METHODSThe study included 17,292 unrelated HCTs with 6-locus high-resolution HLA typing, performed mainly for acute leukemia or related myeloid neoplasms between 2016 and 2020, including 1,523 transplants with PTCy. HLA risk associations were evaluated by multivariable Cox regression models, with overall survival (OS) as primary end point.RESULTSOS was lower in HLA mismatched compared with fully matched transplants (hazard ratio [HR], 1.23 [99% CI, 1.14 to 1.33]; P < .001). This was driven by class I HLA-A, HLA-B, HLA-C (HR, 1.29 [99% CI, 1.19 to 1.41]; P < .001) but not class II HLA-DRB1 and HLA-DQB1 (HR, 1.07 [99% CI, 0.93 to 1.23]; P = .19). Class I antigen-level mismatches were associated with worse OS than allele-level mismatches (HR, 1.36 [99% CI, 1.24 to 1.49]; P < .001), as were class I graft-versus-host peptide-binding motif (PBM) mismatches compared with matches (HR, 1.42 [99% CI, 1.28 to 1.59]; P < .001). The use of PTCy improved GVHD, relapse-free survival compared with conventional prophylaxis in HLA-matched transplants (HR, 0.77 [0.66 to 0.9]; P < .001). HLA mismatching increased mortality in PTCy transplants (HR, 1.32 [1.04 to 1.68]; P = .003) similarly as in non-PTCy transplants (interaction P = .43).CONCLUSIONClass I but not class II HLA mismatches, especially at the antigen and PBM level, are associated with inferior survival in contemporary unrelated HCT. These effects are not significantly different between non-PTCy compared with PTCy transplants. Optimized HLA matching should still be considered in modern HCT.

Biologically Randomized Comparison of Haploidentical Versus Human Leukocyte Antigen-Matched Related Donor Reduced-Intensity Conditioning Hematopoietic Cell Transplantation

Using haploidentical donors for allogeneic hematopoietic cell transplantation (HCT) broadens transplant accessibility to a growing number of patients with hematologic disorders. Moreover, haploidentical HCT with post-transplant cyclophosphamide (PTCy) has become widespread practice due to accumulating evidence demonstrating favorable rates of survival and graft-versus-host disease (GvHD). Most studies comparing outcomes by donor sources have been confounded by variability in conditioning regimens, graft type (peripheral blood [PB] or bone marrow), and post-transplant GvHD prophylaxis (PTCy or non-PTCy), making it difficult to define the effect of donor source on outcomes. Levine Cancer Institute started a transplant and cellular therapy program in 2014, with both haploidentical and matched related donor (MRD) transplants initially performed using a uniform reduced-intensity conditioning (RIC) regimen, PB grafts, and PTCy-based GvHD prophylaxis. This retrospective observational study was conducted to compare the clinical outcomes associated with RIC haploidentical HCT and MRD HCT in patients receiving identical conditioning regimens, graft types, and supportive care. Our transplant database was queried to evaluate demographic characteristics, clinical features, and outcomes of RIC HCT for consecutive patients with hematologic malignancies who received haploidentical or MRD grafts between March 2014 and December 2017. An MRD was the preferred donor source; when unavailable, a haploidentical donor was used. Sixty-seven patients underwent haploidentical HCT and 25 MRD HCT. Overall, characteristics of transplant recipients were similar for the haploidentical and MRD groups; however, haploidentical donors were younger than MRDs (median 36 yr versus 57 yr, P < .0001). Results of univariable analysis showed similar overall survival (OS) for haploidentical and MRD HCT (hazard ratio [HR], 1.15; 95% CI, 0.61 to 2.15; P = .669). One-year, 1-yr, and 5-yr OS were 80.2%, 54.7%, and 41.2% for haploidentical HCT and 76.0%, 55.7%, and 51.1% for MRD HCT, respectively. With a median follow-up of 81.90 months, results of multivariable analysis revealed that donor source (haploidentical versus MRD) was not significantly associated with OS (HR, 0.97; 95% CI, 0.51 to 1.87; P = .933), relapse-free survival (HR, 0.75; 95% CI, 0.42 to 1.35; P = .337), cumulative incidence of relapse (HR, 0.81; 95% CI, 0.39 to 1.70; P = .579), or non-relapse mortality (HR, 1.12; 95% CI, 0.40 to 3.14; P = .827). Cumulative incidences of acute GvHD (aGvHD) and chronic GvHD (cGvHD) were not significantly different for haploidentical and MRD HCT (grades II to IV aGvHD: HR, 1.78; 95% CI, 0.72 to 4.37; P = .210; grades III to IV aGvHD: HR, 2.84; 95% CI, 0.34 to 23.63; P = .335; cGvHD: HR, 1.00; 95% CI 0.36 to 2.76; P = .995). With care that was homogenous in terms of conditioning regimens, graft type, GvHD prophylaxis, and supportive care, 92 patients who were biologically randomized to either haploidentical HCT or MRD HCT after RIC with PTCy had comparable outcomes.

Racial, ethnic, and socioeconomic diversity and outcomes of patients with graft-versus-host disease: a CIBMTR analysis

ABSTRACT

Socioeconomic status (SES) and race/ethnicity have been associated with the outcomes of allogeneic hematopoietic stem cell transplantation (allo-HCT). Certain aspects of graft-versus-host disease (GVHD) management, such as the need for long-term care, prolonged immunosuppressive treatment, and close follow-up for complications, may exacerbate disparities. Adults (≥18 years) reported to the Center for International Blood and Marrow Transplant Research who underwent a first allo-HCT for acute leukemia, myelodysplastic syndrome, or myeloproliferative neoplasm between 2008 and 2018 were included. End points for those developing GVHD included overall survival (OS), transplant-related mortality (TRM), and disease relapse. Models were adjusted for patient- and transplant-related variables. A 2-sided P value < .01 was considered significant. Among the 14 825 allo-HCT recipients, 6259 (42.2%) and 6675 (45.0%) patients developed acute GVHD (aGVHD) and chronic GVHD (cGVHD), respectively. Among patients with aGVHD, non-Hispanic Black patients had increased TRM and overall mortality compared with non-Hispanic White patients; this association disappeared when severity of aGVHD was included in the model. Lower SES was associated with increased risk of disease relapse but not OS or TRM. In patients who developed cGVHD, race and ethnicity were not associated with OS, TRM, or disease relapse. However, the highest quartile of annual household income (≥$80 000) had improved OS and reduced TRM compared with the lowest quartile, after adjusting for race and ethnicity. In summary, race/ethnicity and SES are associated with outcomes after GVHD. Optimizing the health care resources available to low SES patients and strategies to minimize the risk of severe GVHD in non-Hispanic Black patients may improve long-term outcomes.

Proceedings of the 2024 Third Annual ASTCT-NMDP ACCESS Initiative Workshop

The Third Annual Workshop of the American Society for Transplantation and Cellular Therapy (ASTCT) and National Marrow Donor Program (NMDP) ACCESS Initiative occurred on July 23 and 24, 2024. Content from the workshop is provided to inform the hematopoietic cell transplantation (HCT) and cellular therapy (CT) ecosystem about progress and direction of the collaborative. Highlights from the meeting are reviewed, including the inaugural Corporate Roundtable and Advocacy Day, new partnerships with non-profit organizations, and updates on projects from the Awareness, Poverty and Race and Ethnicity Inequity Committees. In addition, the Junior Faculty and Trainee Immersion Program-sponsored efforts in workforce diversity and physician advocacy are presented. Lastly, continued education was provided on patient and caregiver participation as well as community engagement. As it enters its third year, the ASTCT-NMDP ACCESS Initiative will transition from foundation building as a grass roots collaborative to intentional impact in reducing barriers and improving outcome disparities for all patients in need of HCT/CT. Enthusiasm for and participation in the ACCESS Initiative remain high. Both are needed to sustain progress in achieving its goal in enabling all patients in need to receive HCT/CT.

Hematopoietic cell transplantation for DOCK8 deficiency: Results from a prospective clinical trial

BACKGROUND

DOCK8 deficiency is a primary immunodeficiency in which allogeneic hematopoietic cell transplantation (HCT) represents the only known cure. We tested the ability of a busulfan-based regimen to achieve reliable engraftment and high levels of donor chimerism with acceptable toxicity in a prospective clinical trial in DOCK8 deficiency.

OBJECTIVES

To both evaluate the ability of HCT to reverse the clinical phenotype and to correct the immunologic abnormalities by 1 year post HCT.

METHODS

We conducted a prospective HCT trial for recipients with DOCK8 deficiency. Subjects were recruited from October 5, 2010, to December 30, 2022. Donor sources included fully matched related and unrelated donors and haploidentical donors. The reduced toxicity, myeloablative conditioning regimen contained no serotherapy. Graft-versus-host disease (GVHD) prophylaxis included either a calcineurin inhibitor with methotrexate or post-HCT cyclophosphamide (PT/Cy) followed by tacrolimus and mycophenolate mofetil. The trial was later amended to study PT/Cy in all patients. (Pilot Study of Reduced-Intensity Hematopoietic Stem Cell Transplant of DOCK8 [NCT01176006].) RESULTS: Thirty-six subjects, both children and adults (median age 16.4 years), underwent HCT for DOCK8 deficiency. Most patients, 33 of 36 (92%), achieved full (≥98%) donor chimerism in whole blood as early as day +30. With a median potential follow-up of 7.4 years, 29 (80.6%) were alive with no evidence of new DOCK8 deficiency-related complications. PT/Cy was effective in reducing the risk of acute GVHD in patients who had received matched unrelated donor and haploidentical transplants, but it was associated with transient delays in immune-reconstitution and hemorrhagic cystitis.

CONCLUSIONS

A busulfan-based HCT regimen using PT/Cy for GVHD prophylaxis and a broad range of donor types and hematopoietic cell sources were well tolerated, leading to the reversal of the clinical immunophenotype.

Applying Implementation Science in the Field of Transplant and Cellular Therapy

Implementation science (IS) is a systematic way to approach the broader adoption of evidence-based practices and has as its goal to understand and address the gap between research and practice, ensuring that research findings are effectively translated into practice and policy to improve health outcomes and service. We describe the various facets of IS and their relevance to the field of hematopoietic cell transplantation and cellular therapy (HCT/CT) with an emphasis on health equity, community engagement, and systems approach. We also review the similarities and differences among clinical research, quality improvement, and IS. Additionally, we describe how the Center for International Blood and Marrow Transplant Research applies IS across various phases: dissemination, analyzing current practices, and developing implementation intervention strategies. This includes designing studies and evaluations, scaling up operations, and ensuring sustainability. Lastly, we discuss further applications of IS in HCT/CT including the application to prospective research studies, collaboration across the field, and standardization and adoption of best practices. The application of IS in HCT/CT is pivotal to bringing research benefits directly to all patients. Through partnership, open-mindedness, and a commitment to evidence-based practice, we can collectively ensure the greatest impact of research on improving patient outcomes following HCT/CT.

From clones to immunopeptidomes: New developments in the characterization of permissive HLA-DP mismatches in hematopoietic cell transplantation

Mismatching at the HLA-DPB1 locus occurs frequently in hematopoietic cell transplantation with unrelated donors. Despite this, HLA-DPB1 allelic mismatches have traditionally not been considered in patient-donor matching. A T-cell epitope (TCE) model for the functional assessment of permissive mismatches at this locus has nevertheless been adopted in clinical practice. While initially based on a hierarchical immunogenicity elucidated from allorecognition by T-cell clones isolated from a patient, newer developments in the understanding of this model's biological basis, including a central role for immunopeptidome divergence between mismatched allotypes, have prompted changes in the assignment of permissiveness, providing the opportunity for a more granular evaluation of graft-versus-host disease and relapse risks according to the nature and directionality of permissive mismatches. How these advances impact the assessment of permissiveness at HLA-DPB1 and potentially the intelligent selection of donors according to the main clinical goal for different patients is the subject of the present review.

Donor types and outcomes of transplantation in myelofibrosis: a CIBMTR study

ABSTRACT

We evaluate the impact of donor types on outcomes of hematopoietic cell transplantation (HCT) in myelofibrosis, using the Center for International Blood and Marrow Transplant Research registry data for HCTs done between 2013 and 2019. In all 1597 patients, the use of haploidentical donors increased from 3% in 2013 to 19% in 2019. In study-eligible 1032 patients who received peripheral blood grafts for chronic-phase myelofibrosis, 38% of recipients of haploidentical HCT were non-White/Caucasian. Matched sibling donor (MSD)-HCTs were associated with superior overall survival (OS) in the first 3 months (haploidentical hazard ratio [HR], 5.80 [95% confidence interval (CI), 2.52-13.35]; matched unrelated (MUD) HR, 4.50 [95% CI, 2.24-9.03]; mismatched unrelated HR, 5.13 [95% CI, 1.44-18.31]; P < .001). This difference in OS aligns with lower graft failure with MSD (haploidentical HR, 6.11 [95% CI, 2.98-12.54]; matched unrelated HR, 2.33 [95% CI, 1.20-4.51]; mismatched unrelated HR, 1.82 [95% CI, 0.58-5.72]). There was no significant difference in OS among haploidentical, MUD, and mismatched unrelated donor HCTs in the first 3 months. Donor type was not associated with differences in OS beyond 3 months after HCT, relapse, disease-free survival, or OS among patients who underwent HCT within 24 months of diagnosis. Patients who experienced graft failure had more advanced disease and commonly used nonmyeloablative conditioning. Although MSD-HCTs were superior, there is no significant difference in HCT outcomes from haploidentical and MUDs. These results establish haploidentical HCT with posttransplantation cyclophosphamide as a viable option in myelofibrosis, especially for ethnic minorities underrepresented in the donor registries.

Comparing transplant outcomes in ALL patients after myeloablative conditioning in mismatch-related or unrelated donor settings

The optimal myeloablative conditioning regimen for ALL patients undergoing hematopoietic cell transplant (HCT) with an alternative donor is unknown. We analyzed HCT outcomes ALL patients (n = 269) who underwent HCT at our center from 2010 to 2020 in complete remission (CR) after FTBI-etoposide and CNI-based GvHD prophylaxis for matched donor HCT (ETOP-package; n = 196) or FTBI-Fludarabine and post-transplant cyclophosphamide (PTCy)-based prophylaxis for HLA- mismatched (related or unrelated) donors (FLU-package; n = 64). Patients in FLU-package showed a significant delay in engraftment (p < 0.001) and lower cumulative incidence (CI) of any and extensive chronic GVHD (p = 0.009 and 0.001, respectively). At the median follow up of 4.6 years (range 1-12 years); non-relapse mortality, overall or leukemia-free survival and GVHD-free/relapse-free survival were not significantly impacted by the choice of conditioning. However, in patients at CR2 or with measurable residual disease (MRD+), there was a trend towards higher relapse after FLU-package (p = 0.08 and p = 0.07, respectively), while patients at CR1 regardless of MRD status had similar outcomes despite the package/donor type (p = 0.9 and 0.7, respectively). Our data suggests that FLU-package for alternative donors offers comparable outcomes to ETOP-package for matched donor HCT to treat ALL. Disease status and depth of remission at HCT were independent predictors for better outcomes.

Trends in volumes and survival after hematopoietic cell transplantation in racial/ethnic minorities

ABSTRACT

There has been an increase in volume as well as an improvement in overall survival (OS) after hematopoietic cell transplantation (HCT) for hematologic disorders. It is unknown if these changes have affected racial/ethnic minorities equally. In this observational study from the 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 autoHCT and alloHCT over time and trends in OS in 4 racial/ethnic groups: non-Hispanic Whites (NHWs), non-Hispanic African Americans (NHAAs), and Hispanics across 5 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 (hazard ratio [HR] 1.13; 95% confidence interval [CI] 1.04-1.22; P = .004) and pediatric patients (HR 1.62; 95% CI 1.3-2.03; P < .001) had a higher risk of mortality after alloHCT than 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 than in 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.

Real-world and clinical trial outcomes in large B-cell lymphoma with axicabtagene ciloleucel across race and ethnicity

ABSTRACT

Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory (R/R) large B-cell lymphoma (LBCL). Despite extensive data supporting its use, outcomes stratified by race and ethnicity groups are limited. Here, we report clinical outcomes with axi-cel in patients with R/R LBCL by race and ethnicity in both real-world and clinical trial settings. In the real-world setting, 1290 patients who received axi-cel between 2017 and 2020 were identified from the Center for International Blood and Marrow Transplant Research database; 106 and 169 patients were included from the ZUMA-1 and ZUMA-7 trials, respectively. Overall survival was consistent across race/ethnicity groups. However, non-Hispanic (NH) Black patients had lower overall response rate (OR, 0.37; 95% CI, 0.22-0.63) and lower complete response rate (OR, 0.57; 95% CI, 0.33-0.97) than NH White patients. NH Black patients also had a shorter progression-free survival vs NH White (HR, 1.41; 95% CI, 1.04-1.90) and NH Asian patients (HR, 1.67; 95% CI, 1.08-2.59). NH Asian patients had a longer duration of response than NH White (HR, 0.56; 95% CI, 0.33-0.94) and Hispanic patients (HR, 0.54; 95% CI, 0.30-0.97). There was no difference in cytokine release syndrome by race/ethnicity; however, higher rates of any-grade immune effector cell-associated neurotoxicity syndrome were observed in NH White patients than in other patients. These results provide important context when treating patients with R/R LBCL with CAR T-cell therapy across different racial and ethnic groups. ZUMA-1 and ZUMA-7 (ClinicalTrials.gov identifiers: #NCT02348216 and #NCT03391466, respectively) are registered on ClinicalTrials.gov.

Oncogene-induced TIM-3 ligand expression dictates susceptibility to anti-TIM-3 therapy in mice

Leukemia relapse is a major cause of death after allogeneic hematopoietic cell transplantation (allo-HCT). We tested the potential of targeting T cell (Tc) immunoglobulin and mucin-containing molecule 3 (TIM-3) for improving graft-versus-leukemia (GVL) effects. We observed differential expression of TIM-3 ligands when hematopoietic stem cells overexpressed certain oncogenic-driver mutations. Anti-TIM-3 Ab treatment improved survival of mice bearing leukemia with oncogene-induced TIM-3 ligand expression. Conversely, leukemia cells with low ligand expression were anti-TIM-3 treatment resistant. In vitro, TIM-3 blockade or genetic deletion in CD8+ Tc enhanced Tc activation, proliferation, and IFN-γ production while enhancing GVL effects, preventing Tc exhaustion, and improving Tc cytotoxicity and glycolysis in vivo. Conversely, TIM-3 deletion in myeloid cells did not affect allogeneic Tc proliferation and activation in vitro, suggesting that anti-TIM-3 treatment-mediated GVL effects are Tc induced. In contrast to anti-programmed cell death protein 1 (anti-PD-1) and anti-cytotoxic T lymphocyte-associated protein 4 (anti-CTLA-4) treatment, anti-TIM-3-treatment did not enhance acute graft-versus-host disease (aGVHD). TIM-3 and its ligands were frequently expressed in acute myeloid leukemia (AML) cells of patients with post-allo-HCT relapse. We decipher the connections between oncogenic mutations found in AML and TIM-3 ligand expression and identify anti-TIM-3 treatment as a strategy for enhancing GVL effects via metabolic and transcriptional Tc reprogramming without exacerbation of aGVHD. Our findings support clinical testing of anti-TIM-3 Ab in patients with AML relapse after allo-HCT.

Evaluating Socioeconomic, Racial, and Ethnic Disparities in Survival Among Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplants

This study was undertaken to monitor potential disparities in survival after allogeneic hematopoietic stem cell transplantation (HSCT) with the aim of optimizing access and outcomes for minority and low-income patients. We analyzed 463 patients transplanted over a 72-month study period with a median 19-month follow-up, focused on differences by individual patient race/ethnicity and patients' household income derived from geocoded addresses at the census block group level. Patient sociodemographic and clinical characteristics were abstracted from electronic health records and our HSCT registry, including disease category and status, donor age, transplant type, and conditioning. Approximately, 15% of HSCT patients were non-Hispanic Black or Hispanic with a similar proportion from block groups below the median metropolitan Index of Concentration at the Extremes income score. The overall survival probability was 61.8% at 36 months. Non-Hispanic white (63.6%) and especially Hispanic patients (49.2%) had lower survival probabilities at 36 months than non-Hispanic Black patients (75.6%, p = 0.04). There were no other patient characteristics significantly associated with survival at the p < 0.01 level. The lack of significant differences likely reflects the careful selection of patients for transplants. However, the proportion of minority and low-income patients relative to expected disease prevalence in our area population raises important considerations about which patients successfully make it to transplant. We conclude with recommendations to increase the diversity of patients who receive HSCT by reviewing potential barriers in the transplant referral and selection process and advocating for needed psychosocial and community resources.

The Evolution of Hematopoietic Stem Cell Transplantation to Overcome Access Disparities: The Role of NMDP

NMDP recognizes that despite advances in hematopoietic stem cell transplantation (HSCT) and other cell therapies, not all patients have equitable access to treatment, and disparities in outcomes remain. This paper explores the recent work of NMDP to accelerate progress and expand access to more patients through transformative clinical research, particularly in the use of mismatched unrelated donors for HSCT.

Fostering next generation transplant physicians

As opposed to the rapid expansion of hematopoietic cell transplantation (HCT) and other cellular therapies (CT), we are now facing a global shortage of transplant physicians and other professionals to support the activity of HCT/CT. To overcome this obstacle, a variety of approaches are now being undertaken in four international HCT societies. This article aims to share their current attempts to foster the next generation of transplant physicians and allied professionals needed to secure the continued global growth of HCT/CT.

The role and novel use of natural killer cells in graft-versus-leukemia reactions after allogeneic transplantation

Allogeneic hematopoietic cell transplantation (HCT) has transformed over the past several decades through enhanced supportive care, reduced intensity conditioning (RIC), improved human leukocyte antigen (HLA) typing, and novel graft-versus-host disease (GVHD)-prevention and treatment strategies. Most notably, the implementation of post-transplantation cyclophosphamide (PTCy) has dramatically increased the safety and availability of this life-saving therapy. Given reductions in nonrelapse mortality (NRM) with these advances, the HCT community has placed even greater emphasis on developing ways to reduce relapse - the leading cause of death after HCT. When using RIC HCT, protection from relapse relies predominantly on graft-versus-leukemia (GVL) reactions. Donor lymphocyte infusion (DLI), adoptive cellular therapy, checkpoint inhibition, and post-HCT maintenance strategies represent approaches under study that aim to augment or synergize with the GVL effects of HCT. Optimizing donor selection algorithms to leverage GVL represents another active area of research. Many of these strategies seek to harness the effects of T cells, which for decades were felt to be the primary mediators of GVL and the focus of investigation in relapse reduction. However, there is growing interest in capitalizing on the ability of natural killer (NK) cells to yield potent anti-tumor effects. A potential advantage of NK cell-based approaches over T cell-mediated is the potential to reduce NRM in addition to relapse. By decreasing infection, without increasing the risk of GVHD, NK cells may mitigate NRM, while still yielding relapse reduction through identification and clearance of cancer cells. Most T cell-focused relapse-prevention strategies must weigh the benefits of relapse reduction against the increased risk of NRM from GVHD. In contrast, NK cells have the potential to reduce both, potentially tipping the scales significantly in favor of survival. Here, we will review the role of NK cells in GVL, optimization of NK cell match or mismatch, and burgeoning areas of research in NK cell therapy such as adoptive transfer and chimeric antigen receptor (CAR) NK cells.

Nutritional and Body Composition Changes in Paediatric β-Thalassemia Patients Undergoing Hematopoietic Stem Cell Transplantation: A Retrospective Study Using Bioelectrical Impedance Analysis

Objective

This retrospective study evaluated nutritional status and body composition changes in paediatric β-thalassemia (β-TM) patients before and after hematopoietic stem cell transplantation (HSCT), using bioelectrical impedance analysis (BIA), and explored their relationship with HSCT outcomes.

Methods

A cohort of 40 paediatric β-TM patients undergoing allogeneic HSCT was assessed for their nutritional status, anthropometric parameters, including body mass index (BMI), weight, and height, and body composition parameters pre-and post-HSCT, focusing on BIA measurements, including intracellular water (ICW), extracellular water (ECW), fat mass (FAT), fat-free mass (FFM), Skeletal Muscle Mass (SMM), soft Lean Mass (SLM), percent body fat (PBF), Body Cell Mass (BCM), Phase angle (PA) and muscle balance pre- and post-HSCT. Post-HSCT clinical outcomes, including acute graft-vs-host disease (aGVHD), engraftment time, oral mucositis (OM), sinusoidal obstruction syndrome (SOS), and diarrhoea in relation to nutrition status after HSCT were analysed.

Results

After HSCT, 28.21% experienced diminished nutritional status, with 71.43% of those who were wasting before HSCT showing diminished nutritional status, significantly higher than the normal group (18.75%, P = 0.012). Anthropometric changes included significant weight reduction (87.5%, 22.15 ± 7.46 vs 20.74 ± 6.57, P < 0.001) and BMI decrease (90%, 15.19 ± 1.70 vs 14.05 ± 1.48, P < 0.001). Body composition parameters, which are FFM, SMM, SLM, ICW, ECW, BCM, and PA (18.26 ± 5.71 vs 17.27 ± 5.19, 8.68 ± 3.30 vs 7.93 ± 3.02, 17.11 ± 5.28 vs 16.06 ± 4.84, 8.19 ± 2.54 vs 7.62 ± 2.31, 5.15 ± 1.58 vs 4.94 ± 1.47, 11.74 ± 3.63 vs 10.92 ± 3.32, 4.42 ± 0.50 vs 3.90 ± 0.57, respectively, P < 0.001) analysis revealed significant decreases. No significant differences in clinical outcomes were observed based on nutritional status.

Conclusion

Paediatric β-TM patients undergoing HSCT exhibit significant changes in nutrition status and body composition, emphasizing the need for focused attention on malnourished children who are more prone to diminished nutritional status. Comprehensive BIA aids in understanding the impact, urging consideration for extended follow-up and larger cohorts in future research.

Defining and Grading Infections in Clinical Trials Involving Hematopoietic Cell Transplantation: A Report From the BMT CTN Infectious Disease Technical Committee

The Blood and Marrow Transplant Clinical Trials Network (BMT-CTN) was established in 2001 to conduct large multi-institutional clinical trials addressing important issues towards improving the outcomes of HCT and other cellular therapies. Trials conducted by the network investigating new advances in HCT and cellular therapy not only assess efficacy but require careful capturing and severity assessment of adverse events and toxicities. Adverse infectious events in cancer clinical trials are typically graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE). However, there are limitations to this framework as it relates to HCT given the associated immunodeficiency and delayed immune reconstitution. The BMT-CTN Infection Grading System is a monitoring tool developed by the BMT CTN to capture and monitor infectious complications and differs from the CTCAE by its classification of infections based on their potential impact on morbidity and mortality for HCT recipients. Here we offer a report from the BMT CTN Infectious Disease Technical Committee regarding the rationale, development, and revising of BMT-CTN Infection Grading System and future directions as it applies to future clinical trials involving HCT and cellular therapy recipients.

Improving Unrelated Donor Equity: Assessing Mismatched Donor Opportunities with Real-World Data in a Minority-Predominant Cohort

Recent advances in graft-versus-host disease (GVHD) prophylaxis including post-transplant cyclophosphamide (PTCy) and abatacept have significantly improved outcomes following HLA-mismatched allogenic hematopoietic stem cell transplantation (allo-HSCT) and have tremendous potential for reducing racial disparities in donor availability. A recent small study employing bone marrow as the source of stem cells showed similar outcomes after 5/8 versus 7/8 matches and is currently being tested in a larger study using peripheral blood stem cells. In this study, we examine real-world alternative donor HSCT options for a minority-predominant cohort in the Bronx, NY, focusing on the availability of lesser-matched (5/8 to 7/8) donors. Records of patients who underwent HLA typing at Montefiore Medical Center (2019 to 2022) were reviewed. The National Marrow Donor Program registry was queried to evaluate the availability of donors with at least 99% likelihood of HLA match at various levels (5/8, 6/8, 7/8, 8/8). Two hundred forty-one patients were included, 70% were non-White. Although the availability of ≥7/8 donors was less common in non-White patients, 100% of patients from each group had at least one or more 5/8 and 6/8 HLA-matched donors and more than 80% of these patients had >100 potential 5/8 and 6/8 HLA-matched donors. There was no statistical difference by race or ethnicity in the mean number of donors at 5/8 and 6/8 HLA-match levels. We demonstrate through real-world data that patients from diverse ethnic and racial backgrounds have access to 5/8 and 6/8 HLA-matched donors for allo-HSCT, potentially eliminating disparities in donor availability and allowing prioritization of other donor selection characteristics such as donor age, sex, ABO, and B leader matching. Further work is needed to study whether the use of mismatched donors offers a more potent graft-versus malignancy effect and optimal GVHD prophylaxis.

Projected Impact of Omidubicel-onlv on Racial/Ethnic Disparities in Allogeneic Hematopoietic Cell Transplantation (Allo-HCT) Outcomes in Hematologic Malignancies

INTRODUCTION

In a phase III clinical trial (NCT02730299), omidubicel-onlv, a nicotinamide-modified allogeneic hematopoietic progenitor cell therapy, showed rapid hematopoietic and immune recovery compared with standard umbilical cord blood (UCB) transplant across all racial/ethnic groups.

METHODS

A decision-tree model was used to project the effect of omidubicel-onlv availability on addressing health disparities in allogeneic hematopoietic cell transplantation (allo-HCT) access and outcomes for patients with hematologic malignancies. The model used a hypothetical population of 10,000 allo-HCT-eligible US adults, for whom matched related donors were not available. Patients received matched or mismatched unrelated donor, haploidentical, UCB transplant, or no transplant. Scenarios with omidubicel-onlv use of 0% (status quo), 10%, 15%, 20%, and 30% were modeled on the basis of proportional reductions in other allo-HCT sources or no transplant by racial/ethnic group.

RESULTS

Increased omidubicel-onlv use was associated with a higher proportion of patients undergoing allo-HCT, decreased time to allo-HCT, decreased 1-year non-relapse mortality, and increased 1-year overall survival, particularly among racial minorities. In the scenario modeling 20% omidubicel-onlv use, the proportion of Black patients receiving allo-HCT increased by 129%; increases were also observed in Asian (64%), Hispanic (45%), and other (42%) patient groups. Modeled time to allo-HCT improved among transplanted patients (23%) from 11.4 weeks to 8.8 weeks. One-year OS in the overall population increased by 3%, with improvements ranging from 3% for White patients to 5% for Black patients.

CONCLUSION

This study demonstrates that broad access to omidubicel-onlv could increase access to allo-HCT and improve outcomes for patients, with the greatest benefits seen among racial/ethnic minority groups.

Transplantation and Cellular Therapy for Older Adults-The MSK Approach

PURPOSE OF REVIEW

Hematologic malignances more commonly affect older individuals and often present with advanced, higher risk disease than younger patients. Allogeneic and autologous hematopoietic cell transplantation is well-established treatment modalities with curative potential following either frontline treatments for these diseases or salvage therapy in the relapsed or refractory setting. More recently, novel cellular immunotherapy such as chimeric antigen receptor T-cell therapy has been shown to lead to high response rate and durable remission in many patients with advanced blood cancers.

RECENT FINDINGS

Given unique characteristics of older patients, how best to deliver these higher-intensity and time sensitive treatment modalities for them remains challenging. Moreover, their short-term and potential long-term impact on their functional status, cognitive status, and quality of life may be significant considerations for many older patients. All these issues contributed to the lack of access and significant underutilization of these potential curative treatment strategies. In this review, we present up to date evidence to support potential benefits of transplantation and cellular therapy for older adults, their steady improving outcomes, and most importantly, highlight the use of geriatric assessment to help select appropriate older patients and optimize them prior to and following transplantation and cellular therapy. We specifically describe our approach at Memorial Sloan Kettering Cancer Center and encouraging early results from its implementation.

Dual T cell depletion for graft versus host disease prevention in peripheral blood haploidentical hematopoietic cell transplantation for adults with hematological malignancies

The ideal immunosuppressive agents to complement post-transplant cyclophosphamide (PTCy) in PBSC-based haploidentical hematopoietic cell transplantation (haplo-HCT) remain debated. This study looks at our experience with ATG-PTCy-Cyclosporine (CsA) prophylaxis in PB haplo-HCT since 2015. Between October 2015 and December 2021, 157 adults underwent haploidentical hematopoietic cell transplantation (haplo-HCT) using a GVHD prophylaxis regimen comprising rabbit-ATG, PTCy, and CsA. Among these patients, 76.4% received a total ATG dose of 4.5 mg/kg, and 23.5% received 2 mg/kg. T-cell replete peripheral blood stem cell (PBSC) grafts were infused on day 0. The study reported a median follow-up of 32 months (range 0.3-61.64) for survivors. The cumulative incidence of grade II-IV and grade III-IV acute GVHD at day +100 was 26.3% and 9.5%, respectively. Moderate/severe chronic GVHD at 1 year was 19.9%. The 2-year overall survival (OS) was 49.4%, with a relapse-free survival (RFS) of 44.6%. In multivariate analysis, older patients, and those with high/very-high disease risk indices (DRI) were at higher risk for worse OS and higher non-relapse mortality (NRM). The study confirms that using PTCy and ATG (4.5 mg/kg), alongside CsA is safe and effective in preventing GVHD when using peripheral blood as the stem cell source in haploidentical hematopoietic cell transplantation (haplo-HCT).

Utilization and outcome disparities in allogeneic hematopoietic stem cell transplant in the United States

Allogeneic hematopoietic stem cell transplant (allo-HSCT) is increasingly being used in the United States (US) and across the world as a curative therapeutic option for patients with certain high-risk hematologic malignancies and non-malignant diseases. However, racial and ethnic disparities in utilization of the procedure and in outcome following transplant remain major problems. Racial and ethnic minority patients are consistently under-represented in the proportion of patients who undergo allo-HSCT in the US. The transplant outcomes in these patients are also inferior. The interrelated driving forces responsible for the differences in the utilization and transplant outcome of the medical intervention are socioeconomic status, complexity of the procedure, geographical barriers, and the results of differences in the genetics and comorbidities across different races. Bridging the disparity gaps is important not only to provide equity and inclusion in the utilization of this potentially life-saving procedure but also in ensuring that minority groups are well represented for research studies about allo-HSCT. This is required to determine interventions that may be more efficacious in particular racial and ethnic groups. Various strategies at the Federal, State, and Program levels have been designed to bridge the disparity gaps with varying successes. In this review paper, we will examine the disparities and discuss the strategies currently available to address the utilization and outcome gaps between patients of different races in the US.

Expanding donor options: haploidentical transplant recipients are also highly likely to have a 7/8-matched unrelated donor

ABSTRACT

The use of haploidentical related donor (HRD) hematopoietic cell transplants (HCTs) in the United States grew by more than fourfold in the last decade, driven mainly by use of posttransplant cyclophosphamide (PTCy)-based graft-versus-host-disease prophylaxis. However, not all patients have a suitable HRD available. In this study, we explored the existence of unrelated donors (URDs) on the National Marrow Donor Program (NMDP) registry at the 8/8- or 7/8-match level for patients receiving HRD HCT in the United States and reporting to the Center for International Blood and Marrow Transplant Research between 2013 and 2020. The data consist of 9696 HRD HCT recipients. The NMDP search prognosis score and a search simulation were used to estimate counts of URD matches on the registry. NMDP search prognosis varied by patient ancestry, with 27.5% non-Hispanic White having a good score compared with 4.6% of African American HRD HCT recipients. Overall, 34% of recipients had ≥1 8/8-matched URDs and 84% had ≥1 7/8 URDs. Recipients of older HRDs (≥35 years) had a likelihood of between 20%- 65% of having ≥5 existing 7/8-matched URDs who were aged ≤35 years. Donor-selection practices varied among the 10 highest-volume HRD centers: 6 had >20% chance of an existing 8/8-matched URD for their HRD recipients, whereas 4 centers had low likelihood of identifying an 8/8-matched URD. In conclusion, although most US patients undergoing HRD HCT do not have an existing 8/8 URD, the majority have an existing 7/8-matched URD. Studies comparing outcomes in patients receiving either HRD or 7/8-matched URD HCT and PTCy-based graft-versus-host disease prophylaxis may be warranted.

Longitudinal clinical data improve survival prediction after hematopoietic cell transplantation using machine learning

ABSTRACT

Serial prognostic evaluation after allogeneic hematopoietic cell transplantation (allo-HCT) might help identify patients at high risk of lethal organ dysfunction. Current prediction algorithms based on models that do not incorporate changes to patients' clinical condition after allo-HCT have limited predictive ability. We developed and validated a robust risk-prediction algorithm to predict short- and long-term survival after allo-HCT in pediatric patients that includes baseline biological variables and changes in the patients' clinical status after allo-HCT. The model was developed using clinical data from children and young adults treated at a single academic quaternary-care referral center. The model was created using a randomly split training data set (70% of the cohort), internally validated (remaining 30% of the cohort) and then externally validated on patient data from another tertiary-care referral center. Repeated clinical measurements performed from 30 days before allo-HCT to 30 days afterwards were extracted from the electronic medical record and incorporated into the model to predict survival at 100 days, 1 year, and 2 years after allo-HCT. Naïve-Bayes machine learning models incorporating longitudinal data were significantly better than models constructed from baseline variables alone at predicting whether patients would be alive or deceased at the given time points. This proof-of-concept study demonstrates that unlike traditional prognostic tools that use fixed variables for risk assessment, incorporating dynamic variability using clinical and laboratory data improves the prediction of mortality in patients undergoing allo-HCT.

Estimating the Lifetime Medical Cost Burden of an Allogeneic Hematopoietic Cell Transplantation Patient

Allogeneic hematopoietic cell transplantation (allo-HCT) has the potential for curative outcomes for a variety of hematologic malignancies. Current allo-HCT studies often describe the outcomes and costs in the near term; however, research on the lifetime economic burden post-allo-HCT remains limited. This study was conducted to estimate the average total lifetime direct medical costs of an allo-HCT patient and the potential net monetary savings from an alternative treatment associated with improved graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS). A disease-state model was constructed using a short-term decision tree and a long-term semi-Markov partitioned survival model to estimate the average per-patient lifetime cost and expected quality-adjusted life years (QALYs) for an allo-HCT patient from a US healthcare system perspective. Key clinical inputs included overall survival, GRFS, incidence of both acute and chronic GVHD, relapse of the primary disease, and infections. Cost results were reported as ranges based on varying the percentage of chronic GVHD patients that remained on treatment after 2 years (15% or 39%). Over a lifetime, the average per-patient medical cost of allo-HCT was estimated to range from $942,373 to $1,247,917. The majority of the costs were for chronic GVHD treatment (37% to 53%), followed by the allo-HCT procedure (15% to 19%). The expected lifetime QALYs of an allo-HCT patient were estimated as 4.7. Lifetime per-patient treatment costs often exceed $1,000,000 for allo-HCT patients. Innovative research efforts focused on the reduction or elimination of late complications, particularly chronic GVHD, may provide the greatest value to improved patient outcomes.

What is Next in Pediatric B-cell Precursor Acute Lymphoblastic Leukemia

Cure rates now exceed 90% in many contemporary trials for children with B-cell acute lymphoblastic leukemia (ALL). However, treatment remains suboptimal and therapy is toxic for all patients. New treatment options potentially offer the chance to reduce both treatment resistance and toxicity. Here, we review recent advances in ALL diagnostics, chemotherapy, and immunotherapy. In addition to describing recently published results, we also attempt to project the impact of these new developments into the future to imagine what B-ALL therapy may look like in the next few years.