Arai, Sally

ACCESS is a prospective, multicenter phase II trial evaluating peripheral blood stem cell (PBSC) transplantation using 4-7/8 HLA-mismatched unrelated donors (MMUD) with post-transplant cyclophosphamide (PTCy), tacrolimus, and mycophenolate. Adults undergoing first HCT with myeloablative (MAC) or reduced-intensity/nonmyeloablative (RIC/NMA) conditioning were enrolled, with donors aged 18-35 years and matched at 4/8-7/8 HLA loci by high-resolution typing. This expanded analysis includes all enrolled adult PBSC recipients, including the protocol-specified RIC/NMA cohort expansion, to improve precision of outcome estimates and provide descriptive analyses by HLA match level. Among 268 adults, 183 received 7/8 and 85 received <7/8 MMUD grafts; 82.4% of the <7/8 cohort received 6/8 grafts. Median follow-up among survivors was 11.9 months. At 1-year, overall survival was 78.6% (95% CI, 71.9-83.9) in the 7/8 cohort and 85.6% (95% CI, 76.0-91.5) in the <7/8 cohort. One-year relapse, non-relapse mortality, and GVHD-free relapse-free survival were 17.1%, 13.7%, and 51.1% versus 22.8%, 8.4%, and 54.6%, respectively. The cumulative incidence of grade II-IV and grade III-IV acute GVHD by day 100 was 36.6% and 7.7% in the 7/8 cohort versus 28.3% and 5.9% in the <7/8 cohort. Moderate-to-severe chronic GVHD at 1 year was 11.3% versus 7.7%, respectively. Among adult ACCESS recipients treated on a uniform young-donor PBSC/PTCy platform, short-term outcomes with predominantly 6/8 MMUD transplantation were encouraging. Because donor match level was not prospectively assigned and between-group comparisons were exploratory, these findings are descriptive and should not be interpreted as establishing equivalence with 7/8 MMUD transplantation. (Registered as NCT04904588 at CT.gov)

Abstract Newer approaches to control alloreactivity may produce similar transplant outcomes using HLA-mismatched donors vs HLA-matched unrelated donors (MUD). However, prospective comparisons are lacking. BMT CTN 1702 used a donor search prognosis score to assign patients to an 8/8 HLA MUD or the center’s preference of haploidentical related donors (HAPLO), mismatched unrelated donors (MMUD), or umbilical cord blood (UCB). Outcomes of MUD were compared to HAPLO, MMUD, and UCB transplantation after adjusting for covariates. Patients (n = 1179 [93% adults]) underwent transplantation with MUD (n = 772), HAPLO (n = 254), MMUD (n = 112), and UCB (n = 41) at a median of 3.7, 3.4, 3.9, and 3.8 months from enrollment. Posttransplant cyclophosphamide (PTCy) was used in 23.9%, 83.9%, 65.2%, and 0% of MUD, HAPLO, MMUD, and UCB. In multivariate analyses, compared to MUD, survival was lower for UCB (hazard ratio [HR], 2.65; P< .001) but not statistically different for HAPLO and MMUD (HRs, 1.08 and 1.18, respectively). Relapse risk was not significantly different by donor, but treatment-related mortality (HR, 3.31; P< .001) and disease-free survival (HR, 1.99; P = .002) were inferior for UCB but not different for HAPLO and MMUD than MUD. In patients who received PTCy, HAPLO and MMUD were associated with increased grade 3 or 4 acute graft-versus-host disease (GVHD; HR, 2.39 [P = .017] and 2.53 [P = .038], respectively) and chronic GVHD (HR, 1.71 for both; P = .028 and .080) than MUD, but other outcomes were not different. HAPLO or MMUD may be used to expedite transplantation when finding MUD is unlikely. This study was registered at www.clinicaltrials.gov as NCT03904134.

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.

Abstract Allogeneic hematopoietic cell transplantation (HCT) using an HLA mismatched unrelated donor (MMUD) with calcineurin inhibitor-based graft versus host disease (GVHD) prophylaxis results in increased incidence of non-relapse mortality (NRM) and lower survival compared to matched donor HCT. The NMDP sponsored 15-MMUD study demonstrated that post-transplant cyclophosphamide (PTCy)-based prophylaxis following bone marrow derived MMUD HCT resulted in reduced incidence of GVHD and favorable survival. Because marrow grafts can be difficult to procure and vary in quality, we conducted a phase II, prospective, multicenter study to evaluate PTCy-based GVHD prophylaxis in adult recipients of MMUD using peripheral blood stem cell (PBSC) allografts. The primary study aim was to estimate the probability of one-year overall survival (OS) post HCT. Secondary aims were to assess other key clinical endpoints and determine the rate of severe infections. Initial results of the first 70 recipients who received reduced intensity conditioning (RIC) were previously reported by Al Malki et al (JCO 2025) demonstrating a 1-year OS of 78.6% (95% CI, 67% to 86.5%). Here, we report results from a planned expansion of the study that included 123 additional RIC recipients, with updated results from the initial cohort of 70 patients (total N = 193 subjects) treated at 33 centers. Study participants received cyclophosphamide 50 mg/kg (ideal body weight) administered on days 3 and 4 post HCT with tacrolimus and mycophenolate mofetil as previously described (Al Malki, JCO, 2025). The median study participant age was 65.0 (range: 22.9-78.9); 92 (47.7%) of participants were male, and 84 (43.5%) identified as having other than non-Hispanic white ancestry. The HCT comorbidity index was high-risk (>3) in 65 (33.7%). Underlying histologic diagnosis was AML in 96 (49.7%) participants, MDS in 43 (22.3%), ALL in 20 (10.4%), lymphoma or CLL in 24 (12.4%), and CML/other leukemias in 10 (5.2%). Conditioning regimens used were fludarabine and melphalan (100 or 140 mg/m2) (N=120; 62.2%), 2-day busulfan and fludarabine (N=38; 19.7%), and fludarabine, cyclophosphamide and total body irradiation (200 cGy) (N=32; 16.6%). Donor HLA matching (considering HLA-A, -B, -C, and -DRB1) was 7/8 in 131 (67.9%) of participants, 6/8-matched in 51 (26.4%), and 4-5/8-matched in 11 (5.7%) participants. Median donor age was 25.5 years (range: 18.7-35.7). The one-year overall OS estimate was 79.6% (95% confidence interval [CI]: 73.2-84.7). Survival was similar among HLA 7/8-matched donor recipients (77.8%, 69.7-84%) and <7/8 matched donor recipients (83.7%, 71.8-90.9%). The one-year GVHD-free, relapse-free survival (GRFS) was 49.9% (42.6-56.9%) and the one-year progression-free survival was 70.2% (63.2-76.2%). The one-year cumulative incidence (CI) rates of NRM and relapse were 12.5% (8.3-17.6%) and 17.3%(12.3-23%), respectively. The 6-month CI of grade II-IV and grade III-IV acute GVHD were 40.0% (33.0-46.8%) and 7.8% (4.6-12.1%), respectively. The one-year incidence of all chronic GVHD and severe chronic GVHD were 15.6% (10.7-21.2%) and 3.7% (1.6-7%), respectively, by NIH consensus criteria. The CI of grade 1-4 cytokine release syndrome (CRS) by day 7 post HCT was 28.0% (21.8-34.9%), and grade 3-4 CRS was 0.5% (0-2.9%). Primary engraftment failure occurred in 9 (4.7%) participants. Among 145 evaluated participants, 85.5% were >95% donor in blood chimerism at day 100 post HCT. Within the first 100 days after HCT, CTCAE grade 2-5 infections occurred in 113 (58.5%) of participants and grade 3-5 infections occurred in 59 (30.6%) of participants. The most common etiologies of grade 2-5 infections were bacterial (N=78), followed by viral (N=48). The most common grade 3-5 non-infectious toxicities were cardiac disorders, which occurred in 4 (2.1%) of participants. In conclusion, the results including this expansion cohort demonstrate encouraging 1-year OS, NRM and relapse rates in RIC recipients of PTCy-based GVHD prophylaxis and PBSC allografts from MMUDs. This larger cohort of 193 recipients re-affirm the results from the initial cohort with greater robustness.Measures to mitigate infection risk are likely to further improve outcomes. Reducing the dose of PTCy is a candidate approach currently being tested in the ongoing OPTIMIZE trial (NCT 06001385).These results support the extension of PBSC MMUD using PTCy to individuals who lack an HLA-matched donor and require RIC HCT.

Abstract Allogeneic hematopoietic cell transplantation (HCT) remains inaccessible to many patients, particularly those of non-European ancestry, due to the limited availability of matched unrelated donors (URD). While single-HLA mismatched donors (7/8) often yield acceptable outcomes, URD HCT mismatched at ≥ 2 HLA alleles (<7/8) has historically been associated with poor survival and prohibitive toxicity. Post-transplant cyclophosphamide (PTCy) has improved outcomes following mismatched unrelated donor (MMUD) HCT, potentially enabling less stringent donor matching. Whether the degree of donor-recipient HLA disparity remains prognostic after MMUD HCT when PTCy is used is unknown. The ACCESS trial (NCT04904588) was conducted by the Center for International Blood and Marrow Transplant Research Clinical Research Organization and prospectively evaluated PTCy-based graft versus host disease (GVHD) prophylaxis in adult recipients of 4–7/8 (HLA-A, -B, -C and -DRB1) MMUD peripheral blood stem cells (PBSC) from donors age ≤35 years old following either myeloablative (MAC) or reduced intensity/non-myeloablative (RIC/NMA) conditioning. This analysis focused on all adult recipients of <7/8 grafts enrolled on the study across both conditioning strata, with descriptive comparison to patients who received 7/8 MMUD PBSC grafts. The primary endpoint was 1-year overall survival (OS). Secondary endpoints included primary graft failure (PGF), non-relapse mortality (NRM), relapse, acute and chronic GVHD, and GVHD-free relapse-free survival (GRFS). A total of 268 adults received MMUD PBSC grafts: 85 with <7/8 matches (MAC: n=23; RIC/NMA: n=62) and 183 with 7/8 matches (MAC: n=52; RIC/NMA: n=131). Among <7/8 recipients, median age was 57 years old (range, 24–78), 49% were male, with diagnoses of acute myeloid leukemia (AML) (55%), myelodysplastic syndromes (MDS) (15%), and lymphoma (14%). HLA mismatch distribution in the <7/8 group was 6/8 in 82%, 5/8 in 14%, and 4/8 in 4%. Most received fludarabine/melphalan (44%) or myeloablative busulfan/fludarabine (21%). Median CD34+ cell dose was 5.5 ×10^6/recipient kg (range: 3.2-8.0) and 75% of grafts were cryopreserved prior to infusion. Median donor age was 25.8 (range: 18.7-35.7) in the 7/8 group and 25.0 (range: 18.3-34.8) in the <7/8 group. The <7/8 cohort was racially and ethnically diverse, with 61% identifying as other than non-Hispanic white. The 7/8 cohort had a median age of 63 years old (range, 20–79), with 52% male. Disease distribution, conditioning intensity, and infused cell doses were similar to the <7/8 group. A smaller proportion of grafts were cryopreserved (61%), and 47% of patients identified as other than non-Hispanic White. One-year OS for <7/8 recipients was 86% (95% CI: 76–92%), compared to 79% (95% CI: 72–84%) in 7/8 recipients. One-year incidence of relapse was 23% (95% CI: 14–33%) in the <7/8 group and 17% (95% CI: 12–23%) in 7/8 recipients; NRM was 8% (95% CI: 4–16%) and 14% (95% CI: 9–19%), respectively. GRFS was 55% (95% CI: 43–65%) for <7/8 and 51% (95% CI: 44–58%) for 7/8 recipients. PGF occurred in 8% (95% CI: 3–18%) of <7/8 RIC recipients and 3% (95% CI: 1–8%) of 7/8 RIC recipients; no MAC recipients had PGF. At 6 months post-HCT, grade II–IV acute GVHD occurred in 34% (95% CI: 24–44%) of <7/8 patients and 39% (95% CI: 32–46%) of 7/8; grade III–IV acute GVHD was observed in 7% (95% CI: 3–14%) and 8% (95% CI: 5–13%), respectively. Moderate to severe chronic GVHD (NIH consensus criteria) at one year occurred in 8% (95% CI: 3–15%) of <7/8 recipients and 11% (95% CI: 7–16%) of 7/8 recipients. When grouped by conditioning intensity, 1-year outcomes within the <7/8 cohort were: OS 91% after MAC and 84% after RIC/NMA; relapse in 32% after MAC and 20% after RIC/NMA, respectively; GRFS was 53% for MAC and 55% for RIC/NMA; and NRM remained low at 9% after MAC and 8% after RIC/NMA. In this cohort of adult recipients of <7/8 MMUD PBSC grafts with PTCy-based GVHD prophylaxis enrolled on the ACCESS study, 1-year OS exceeded 80% and was comparable to 7/8 recipients. Relapse, NRM, and GVHD rates were similarly favorable and consistent with outcomes reported in 7/8 donor recipients. These findings support extending suitable MMUD match considerations to include 4-6/8 in the context of PTCy, potentially enabling near-universal donor access, while allowing for optimization of other non-HLA donor factors.

PURPOSE The likelihood of finding a human leukocyte antigen (HLA)–matched unrelated donor (MUD) for hematopoietic cell transplantation can be predicted using a donor search prognosis score. Patients without a MUD may use alternative donors (haploidentical related, mismatched unrelated, or umbilical cord blood). METHODS This multicenter biological assignment trial was conducted by the Blood and Marrow Transplant Clinical Trials Network (BMT CTN 1702). Eligibility criteria were broad to mirror clinical practice. The primary end point was 2-year survival from evaluability and compared between those Very Likely (>90%) and Very Unlikely (<10%) to find a MUD. All other patients, Less Likely to find a MUD, were enrolled in an observational arm. Transplant outcomes were compared for all three groups. RESULTS A total of 1,751 evaluable patients at 47 centers were Very Likely (54.7%), Less Likely (29.5%), and Very Unlikely (15.8%) to identify a MUD. Survival did not differ in univariate (hazard ratio [HR], 1.00 [95% CI, 0.82 to 1.21]; P = .98) or multivariate (HR, 1.07 [95% CI, 0.86 to 1.33]; P = .56) analyses between the Very Unlikely and Very Likely groups, measured through 2 years from the beginning of a search for a MUD or alternative donor. Of the transplanted patients (n = 1,179), MUD was used for 94% of the Very Likely, 38% of Less Likely, and 9% of Very Unlikely patients. Multivariate analyses showed no differences in relapse, treatment-related mortality, disease-free survival, and acute and chronic graft-versus-host diseases for the three search prognosis groups after transplantation. CONCLUSION Using a donor search prognosis strategy to prioritize an alternative donor for patients Very Unlikely to find a MUD resulted in survival and transplant outcomes that were not statistically different compared with those Very Likely to find a MUD.

ABSTRACTThe optimal conditioning schedule and CD34+ cell dose for autologous stem cell transplantation (ASCT) for AL amyloidosis is unknown. Patients (n = 1704) who underwent ASCT for AL amyloidosis between 2003 and 2020 in 9 centers were included. Data on melphalan conditioning dose, number of conditioning days, whether a rest day between conditioning and stem cell infusion was given or not, and infused CD34+ cell dose were collected. Full‐dose melphalan (≥ 180 mg/m2) was administered in 63.7% of the patients, and 80.4% had melphalan split into 2‐day conditioning. A rest day (day −1) between the conditioning regimen and stem cell infusion was provided in 52.5% of patients. The median infused CD34+ cell count was 4.7 × 106/kg. An infused CD34+ cell count ≥ 4.5 × 106/kg was associated with a shorter time to neutrophil and platelet engraftment. In a nominal regression analysis, full‐dose melphalan, 1‐day melphalan conditioning, and omitting a rest day between conditioning and stem cell infusion were independent predictors of post‐ASCT higher deep hematological response. The median follow‐up was 8.6 years, and 38% of patients died. Independent predictors of superior overall survival in multivariate Cox regression analysis included full‐dose melphalan, having no rest day, and infused CD34+ cells ≥ 4.5 × 106/kg. Independent predictors of higher day‐100 transplant‐related mortality (TRM) in nominal logistic regression analysis included poorer performance status, NT‐proBNP/BNP ≥ 1800/400 pg/mL, serum albumin < 2.5 g/dL, CD34+ cells < 4.5 × 106/kg, and not having a rest day. In conclusion, 1 day of melphalan conditioning and administration of CD34+ cells ≥ 4.5 × 106/kg are recommended for ASCT in AL amyloidosis.

Autologous stem cell transplantation (ASCT) in AL amyloidosis effectively produces a high overall hematological response rate, complete response rate, and durable remissions. However, it is a high-dose chemotherapy-based therapy with high morbidity which can be offered only to a subset of AL amyloidosis patients who are considered fit for this therapy. Transplant-related mortality (TRM) in AL amyloidosis has decreased over the past three decades due to improvement in patient selection. New therapeutic options question the utilization of ASCT. A model to predict TRM can improve the decision-making process, patient selection and further reduce TRM. AL amyloidosis patients (n=1718) from 9 centers globally, transplanted in the years 2003-2020 were included. Pre-ASCT variables of interest were assessed for association with Day-100 all-cause mortality, including age at ASCT (≥ 60 years), sex, light chain isotype, ECOG performance status (ECOG PS; 0, 1 and 2/3), the difference between involved and uninvolved light chains (dFLC; ≥180 mg/L), N-terminal prohormone of B natriuretic peptide (NT-proBNP; ≥1800 pg/mL) or B-type natriuretic peptide (BNP; ≥400 pg/mL), left ventricle ejection fraction (LVEF, &lt;50%), interventricular septum (&gt;16 mm), corrected diffusing capacity for carbon monoxide (cDLCO; ≤65% of predicted), forced expiratory volume in one second (FEV1; ≤65% of predicted), serum albumin (&lt;2.5 g/dL), estimated glomerular filtration rate (eGFR; &lt;30 mL/min/m2), alkaline phosphatase (&gt;X2 upper limit of normal), and systolic blood pressure (&lt;100 mmHg). Troponins could not be included in our modeling given the multitude of assays used across institutions and periods that could not be reconciled. A random forest (RF) classifier with 10-fold cross-validation was used to assist in variable selection. The final model variables were selected based on statistical performance and clinical relevance. The model was fitted using logistic regression. The median age at ASCT was 58, and 40% of patients were women. The most frequently involved organs were the kidneys (69%) and the heart (52%). Mayo 2004 stages I and II were collectively present in 83% of patients. Day-100 TRM occurred in 75 patients (4.4%) with the 3 main causes being shock (n=27), cardiac arrhythmia (n=26), and organ failure (n=22). Age at ASCT, sex, and light chain isotype were not predictors of Day-100 TRM. Across the other pre-ASCT variables, adverse features were present from 6.9% (LVEF &lt;50%) to 25.8% (dFLC ≥180 mg/L) of patients. Ten factors were associated with Day-100 TRM on univariate analysis. The odds ratio of these variables ranged from 1.6 to 10.2. RF classifier using all these variables identified a model with an area under the curve (AUC) of 0.72±0.12. Using the importance hierarchy function to refine the model selection, a 4-variable model [NT-proBNP/BNP ≥1800/400 pg/mL, serum albumin &lt;2.5 g/dL, ECOG PS 1 or 2/3, and systolic blood pressure &lt;100 mmHg] was built with an AUC of 0.70±0.12. Based on logistic regression coefficients, ECOG PS 2/3 was assigned two points, while other adverse predictors were assigned 1-point each (model score range 0-5). We then applied the model scoring to our study population. Score distribution was as follows: 0 (n=431, 25.1% of patients), 1 (n=688,40.1%), 2 (n=413, 24.0%), and 3 and above (n=186, 10.8%). Day-100 TRM rates were 0.46%, 3.2%, 5.8%, and 14.5% for 0, 1, 2, and ≥3 points, respectively. The respective rates for the years 2003-2011 were 1.1%, 3.3%, 6.4%, and 19.2%, while for the years 2012-2020 0%, 3.1%, 5.2%, and 8.4%. We developed a simple clinical tool to predict the Day-100 TRM risk in AL patients undergoing ASCT. This tool will allow more informed decision making weighing the individual benefits and risks of ASCT compared to other therapies.

Introduction: Adults older than 60 years constitute 20-25% of newly diagnosed classic Hodgkin lymphoma (cHL) and have inferior outcomes compared to younger patients (pts). Salvage therapy followed by an autologous stem cell transplant (ASCT) is a potentially curative option for pts with relapsed/refractory (R/R cHL). There is limited data regarding outcomes of older adults with R/R cHL who undergo ASCT in the current era where novel agents are employed in the R/R setting, in comparison with younger patients. Methods: This multicenter, international, retrospective study of 18 participating institutions included adults with R/R cHL who underwent ASCT from January 1, 2010 through December 31 2020. Retrospective chart review was performed to collect data on patient and disease characteristics at relapse, including lines and type of salvage therapy, pre-ASCT response by PET, and use of brentuximab vedotin (BV) as consolidation post-ASCT. Study objectives were to assess progression-free survival (PFS), overall survival (OS), and the probability of non-relapse mortality (NRM) with relapse as a competing event. NRM was defined as death without preceding relapse. Results: Of the total 1172 adults with R/R cHL enrolled in the parent cohort, 96 (8.1%) were age 60 years or older at the time of ASCT. In this older cohort, the median age was 66 years (range: 60-72). 54 (56%) were age 60-64, 31 (32%) were of age 65-69 and 11 (11%) were of age 70-72. 59 (61%) were male, 63 (66%) had advanced stage disease, 17 (18%) had bulky disease, 37 (39%) had B symptoms and 38 (40%) had extranodal disease. All patients (pts) received ABVD or ABVD-like frontline therapy. The median time to relapse was 6 months (range: 0-174). 48 pts (50%) relapsed within a year after completion of frontline treatment and 25 (26%) had primary refractory disease. Salvage therapy prior to ASCT included platinum-based chemotherapy (65%), BV-based regimen (34%), and PD-1 inhibitor-based regimens (3%). 16 pts (16%) underwent ASCT after &gt;1 line of salvage therapy and 75 (78%) underwent ASCT after achieving a complete metabolic response (CMR). 14 pts (14.6%) received BV consolidation. Median follow-up for entire population was 53.4 months (range: 0.3-199.0). In older adults, the 5-year PFS was 54.2% (CI95: 43.4-67.6) not statistically different compared to pts &lt;60 years (67.7% (CI95: 64.3-71.3), p=0.2). However, 5-year OS was inferior in older adults: 71.9% (CI95: 43.4-67.6) vs. 82.6% (CI95: 43.4-67.6) in pts &lt;60 years (p &lt;0.0001)). In pts ≥60, 26 (27%) died including 12 (12.5%) without preceding relapse. Older adults had 3-month, 1-year and 5-year probability of NRM of 5.2% (CI95: 2.2-12.2), 7.5% (CI95: 3.6-15.3), and 10.9% (CI95: 5.8-20.8), respectively. NRM was significantly higher in older adults compared to pts &lt;60 who had 3-month, 1-year and 5-year probability of NRM of 0.3% (CI95: 0.1-1.0), 0.9% (CI95: 0.5-1.7), and 2.5% (CI95: 1.6-3.9), respectively (p&lt;0.0001). Older adults had 3-month, 1-year and 5-year probability of relapse of 1% (CI95: 0.2-7.3), 7.5% (CI95: 3.6-15.3), and 28.6% (CI95: 19.1-42.1), respectively, which did not differ significantly from younger pts (p=0.3) who had 3-month, 1-year and 5-year probability of relapse of 0.6% (CI95: 0.3-1.3), 5.1% (CI95: 3.8-6.6), and 29.9% (CI95: 26.6-33.5), respectively. Conclusions: Although older adults with cHL are more likely to relapse after frontline treatment, only a minority of pts (&lt;10%) in this large multicenter cohort underwent ASCT at age ≥60. In select older adults who underwent ASCT, the risk of relapse was similar to younger pts, but NRM was significantly higher, especially in the early post-ASCT period. Detailed assessment of comorbidity scores, toxicities of salvage therapies, and prognostic factors will be presented at the conference.

Background: Immunosuppressive therapy (IST) is considered the standard front-line treatment for acquired severe aplastic anemia (SAA) for pts &gt;40 years. For pts aged &lt;40 years who have a suitable human leukocyte antigen (HLA)-matched sibling donor (MSD), hematopoietic stem cell transplantation (HSCT) is recommended. This recommendation is based on the toxicity associated with alternative donors; haploidentical (HAPLO) and unrelated donor (URD) HSCT for patients who lack a MSD. However, the hematopoietic response after IST is ~ 70-80%, even after augmentation with eltrombopag in the front-line setting, and failure-free survival (FFS, defined as patients alive and in remission without clonal disease more than 10 years after IST) remains &lt; 40%. HSCT is often employed as a second line salvage therapy for those who do not respond to IST or have disease recurrence. However, outcomes after HSCT are often compromised because of IST-related complications such as clonal evolution, development of donor specific antibodies, infectious adverse events and organ dysfunction. In contrast, a successful allogeneic HSCT leads to relatively prompt hematopoietic and immune reconstitution and mitigates the risk of secondary clonal disease. Innovations in recent decades, such as improved graft versus host disease (GVHD) prophylaxis and supportive care, have steadily reduced the morbidity and mortality of adults undergoing HSCT from unrelated or mismatched donors and expanded the donor pool such that almost all pts with SAA have a potential donor available. The use of post-transplant cyclophosphamide (PTCy) is now a well-established approach to facilitate engraftment and mitigate the risk of GVHD. It was successfully used in relapsed/refractory SAA pts using HAPLO donors in the multi-center BMT CTN #1502 trial (NCT02918292). Similar PTCy based approaches have been effective in the upfront setting with HAPLO and URD in small single center studies. Opened in July 2024, the CureAA trial (NCT06517641), seeks to increase donor options for SAA pts who have not yet received IST by using PTCy based GVHD prophylaxis for HSCT using HAPLO or URD. Study Design and Methods: This BMT CTN study (#2207) is a prospective multi-center phase II trial to assess efficacy of HSCT using HAPLO or URD bone marrow with a reduced intensity, thymoglobulin (ATG)-containing preparative regimen and PTCy GVHD prophylaxis in previously untreated SAA pts. This trial has two parallel cohorts for each donor type, HAPLO and URD, with an accrual goal of 30 participants in each cohort. All will receive ATG (0.5mg/kg on day -9 and 2mg/kg on days -8 and -7), cyclophosphamide (14.5mg/kg on days -6 and -5), fludarabine (30mg/m2 on days -6 to -2), 400 cGy total body irradiation (day -1 in a single fraction), a marrow graft (goal &gt;2.5 x 108 nucleated cells per kg of recipient) on day 0 and PTCy (50mg/kg on days +3 and +4). Additionally, participants receive tacrolimus (until day +180) and mycophenolate mofetil days +5-35. The primary objective of the trial is to estimate the GVHD-free failure-free survival (GFFS) rate at 1 year after initiation of conditioning. GFFS is a composite endpoint of survival without grade III-IV acute GVHD, chronic GVHD requiring immunosuppression, or primary or secondary graft failure requiring second definitive therapy within 1 year after initiation of conditioning. Secondary objectives will evaluate patient survival, engraftment, transfusion dependence, cumulative incidence of GVHD and hematologic response. Health related quality of life, healthcare utilization and financial toxicity data will also be collected. These endpoints will allow clinical comparison with current results achieved with upfront IST in other studies. We hypothesize that this HSCT approach will improve survival without significant transplant-associated morbidity by using a low toxicity regimen that reduces rates of GVHD and provides rapid hematologic recovery without graft failure, thereby making HAPLO and URD HSCT a viable option for initial upfront treatment of SAA. The ability to use mismatched donors will also ensure that a HSCT option is more widely available to all racial/ethnic groups. This collaborative study was funded by grants U10HL069294, U24HL138660 to the BMT CTN from the NHLBI/ NCI, along with funding from Sanofi. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.