Bupp, Caitrin

Importance Allogeneic hematopoietic cell transplant (HCT) is curative for hematologic cancers, yet access remains inequitable for racially and ethnically underrepresented and socioeconomically disadvantaged populations, making the goal of having a suitable donor for every patient who needs a transplant challenging. The ACCESS trial broadened access by enrolling patients without matched donors, who instead received an HCT from a mismatched unrelated donor. Objective To compare baseline characteristics of ACCESS trial participants with participants enrolled in a similar clinical trial and a patient-reported outcome (PRO) protocol cohort. Design, Setting, and Participants This cross-sectional study included adult participants (aged ≥18 years) from 3 cohorts—the ACCESS trial (2021-2024), BMT CTN 1703 trial (2019-2021), and Center for International Blood and Marrow Transplant Research (CIBMTR) PRO Protocol observational study (2020-2025)—who completed a baseline PRO survey. The ACCESS and PRO Protocol cohorts were stratified by conditioning intensity (myeloablative [MAC] vs reduced-intensity and nonmyeloablative [RIC/NMA]); all BMT CTN 1703 participants received RIC/NMA. Exposure Hematopoietic cell transplant. Main Outcomes and Measures Racial and ethnic diversity, insurance type, education, and income were compared among cohorts using counts and percentages, and socioeconomic and structural disadvantage were measured using the Social Vulnerability Index and Comprehensive Score for Financial Toxicity–Functional Assessment of Chronic Illness Therapy. Results Baseline surveys were completed by 208 participants in the ACCESS trial (median [range] age at transplant, 62.3 [20.4-78.9] years; 108 male [51.9%]), 122 participants in the PRO Protocol study (median [range] age at transplant, 63.9 [21.1-78.0] years; 67 male [54.9%]), and 342 participants in the BMT CTN 1703 trial (median [range] age at transplant, 66.9 [20.7-78.6] years; 218 male [63.7%]). Participants in ACCESS were more racially and ethnically diverse, with 15 (7.2%), 25 (12.1%), 46 (22.2%), 110 (53.1%), and 11 (5.3%) of Asian, Black or African American, Hispanic or Latino, White, and other race and ethnicity, respectively, compared with 4 (3.3%), 2 (1.6%), 8 (6.6%) 104 (85.2%), and 4 (3.3%), respectively, in the PRO Protocol and 10 (3.0%), 0, 16 (4.8%), 302 (91.0%), and 4 (1.2%), respectively, in the BMT CTN 1703 trial. Participants in ACCESS were more likely to have Medicaid (36 [18.1%]) vs PRO Protocol (8 [6.7%]) and BMT CTN 1703 (16 [5.1%]) participants and reported lower education (some college or an associate’s degree: 103 [49.5%] vs 73 [59.8%] in the PRO Protocol; postcollege education: 34 [17.3%] vs 35 [29.2%] in the PRO Protocol) and household income (<$40 000 annually: 25 [24.0%] vs 8 [11.6%] in the PRO Protocol and 7 [38.9%] in the BMT CTN 1703 trial). Median Social Vulnerability Index scores were highest among participants in the ACCESS MAC group (median [range], 0.72 [0.01-0.97] vs 0.61 [0.16-0.78] in the PRO Protocol MAC group), and 16 participants [27.6%] in the ACCESS MAC group reported moderate to severe financial toxicity. The ACCESS participants lived closer to transplant centers, especially in the RIC/NMA group (median [IQR], 28 [14-75] miles vs 47 [16-96] miles for BMT CTN 1703 participants and 49 [21-104] miles for PRO Protocol participants). Conclusions and Relevance This cross-sectional study of clinical trial participants and a clinical cohort found that the ACCESS trial enrolled a more racially and ethnically diverse and socioeconomically disadvantaged population. Trial designs that broaden eligibility could expand access to HCT, highlighting the need for systemic interventions to ensure equity.

SummaryTransplant‐associated thrombotic microangiopathy (TA‐TMA) is a complication of allogeneic transplantation (allo‐HCT). The incidence and risk factors associated with TA‐TMA are not well known. A retrospective analysis from the Center for International Blood and Marrow Transplant Research (CIBMTR) was conducted including patients receiving allo‐HCT between 2008 and 2016, with the primary objective of evaluating the incidence of TA‐TMA. Secondary objectives included identification of risk factors associated with TA‐TMA, and the impact of TA‐TMA on overall survival and the need for renal replacement therapy (RRT). Among 23,665 allo‐HCT recipients, the 3‐year cumulative incidence of TA‐TMA was 3%. Variables independently‐associated with increased incidence of TA‐TMA included female sex, prior autologous transplant, primary disease (acute lymphoblastic leukaemia and severe aplastic anaemia), donor type (mismatched or unrelated donor), conditioning intensity (myeloablative), GVHD prophylaxis (sirolimus + calcineurin inhibitor), pre‐transplant kidney dysfunction and acute GVHD (time‐varying effect). TA‐TMA was associated with higher mortality (HR = 3·1, 95% Confidence Interval [CI] = 2·8–16·3) and RRT requirement (HR = 7·1, 95% CI = 5·7–311·6). This study provides epidemiologic data on TA‐TMA and its impact on transplant outcomes. Increased awareness of the risk factors will enable providers to be vigilant of this uncommon but serious transplant complication. The results will also provide benchmarking for future study designs and comparisons.