He, Naya

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.

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.

ABSTRACTBackgroundIn this study, we compared outcomes of intensified myeloablative conditioning regimens using large registry data from Japan (Japanese Society for Transplantation and Cellular Therapy) and the United States (Center for International Blood and Marrow Transplant Research).MethodsAdult patients who underwent their first myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) for acute leukemia in remission between 2010 and 2018 using conditioning regimens of cyclophosphamide plus total‐body irradiation (CY/TBI), CY/TBI+cytarabine (AraC), or CY/TBI+etoposide (VP16) were included.ResultsThe acute myeloid leukemia (AML) cohort (N = 480, 38.8%) indicated that overall survival (OS) was poorer in CY/TBI+AraC (hazard ratio [HR] 1.46, p < 0.001) and CY/TBI+VP16 (HR 1.39, p = 0.059) compared to CY/TBI. Relapse was not suppressed, while treatment‐related mortality (TRM) was significantly higher (HR 1.78 and 1.74, p < 0.001 and 0.018, respectively). In the acute lymphoblastic leukemia (ALL) cohort (N = 3901, 61.2%), OS was comparable among these regimens. With intensified regimens, relapse was significantly suppressed in CY/TBI+VP16 (HR 0.74, p = 0.005), while TRM was higher (HR 1.21, p = 0.077). No interactions were observed regarding the country.ConclusionIn AML adding AraC and VP16 to CY/TBI had an adverse effect on OS. Conversely, in ALL, adding VP16 or AraC to CY/TBI did not affect survival, but the addition of VP16 reduced the risk of relapse.Clinical Trial RegistrationThe authors have confirmed clinical trial registration is not needed for this submission.

Abstract Allogeneic hematopoietic cell transplantation (allo-HCT) can provide curative treatment for hematologic malignancies but is associated with prolonged lymphopenia that may contribute to an increased risk of infection and relapse, resulting in decreased survival. We hypothesized that patients with rapid and robust CD4 T- and B-cell recovery have improved survival and decreased treatment-related mortality (TRM). A total of 2089 patients were included who underwent first allo-HCT for acute myeloid leukemia/acute lymphoblastic leukemia/myelodysplastic syndrome from 2008 to 2019 reported to the Center for International Blood and Marrow Transplant Research with available CD4 counts at days 100 and 180. Patients (median age, 51 years [range, 2-75]) were categorized into 4 groups based on graft-versus-host disease (GVHD) prophylaxis: ex vivo T-cell depletion (TCD/CD34), posttransplant cyclophosphamide, calcineurin inhibitor alone (CNI), or CNI with antithymocyte globulin. Based upon survival, we could identify optimal cutoff points for CD4+ T cells in pediatric (age of &lt;20 years) patients: 248 × 106/L and 420 × 106/L at days 100 and 180, respectively; and in adult (age of &gt;20 years) patients: 104 × 106/L and 115 × 106/L at days 100 and 180, respectively. In adults, day-100 CD4 count was associated with overall survival (OS), progression-free survival (PFS), and TRM but not relapse, incidence of infections, or chronic GVHD. Similarly, CD4 counts above the cutoff point at day 180 in adults were associated with improved OS, PFS, and TRM but no other outcomes. No clinical associations for CD4 counts were identifiable in pediatric patients. These findings underscore the importance of tailoring transplant strategies for adults to optimize immune recovery and improve patient outcomes.

Background: A donor search prognosis score based on HLA type and race/ethnicity can classify patients into 3 groups based on the likelihood of finding an HLA-matched (8/8) unrelated donor (MUD): Very Likely (44% of the population), Likely (41%) and Very Unlikely (15%). Previous studies showed that &gt;90% of Very Likely, 26% of Likely and &lt;10% of Very Unlikely patients used a MUD for their hematopoietic cell transplants (HCT), with the rest using other donor sources (mismatched unrelated donor, cord blood, or haploidentical relative). For some patients, prolonged efforts to identify a MUD might be futile and delay HCT, leading to increased morbidity, greater chance for relapse and disease resistance, and worse HCT outcomes. BMT CTN 1702 (NCT03904134) was the first national study to track the entire donor search identification process. Designed as a biologic assignment study, the goal was to estimate and compare overall survival between two arms: patients who are Very Likely to find a MUD versus those who are Very Unlikely to find a MUD. It tested whether provision of a donor search prognosis score to centers could prevent prolonged futile searches for the Very Unlikely group and improve their transplant rates and outcomes, compared to the Very Likely group. Methods: Eligible diagnoses included acute leukemia, myelodysplastic syndromes, lymphoma, acquired aplastic anemia and sickle cell disease. Patients could be consented at any time after diagnosis until an unrelated donor search was started. Consented patients became evaluable only after it was determined that no appropriate HLA-identical siblings were available. The primary endpoint was survival time after the patient was declared evaluable, regardless of whether HCT occurred, and was compared between the Very Unlikely and Very Likely groups. The target enrollment was 1732 evaluable patients. Because this was a biologic assignment trial and not a randomized trial, formal comparisons of overall survival between the Very Likely and Very Unlikely groups were done using a covariate-adjusted Cox proportional hazards model. The following covariates were a priori specified for adjustment in the model, according to the statistical analysis plan: sex, age, Karnofsky Performance Score (KPS), race/ethnicity, disease, disease status, and interval from consent to evaluability. Results: 1751 evaluable patients were enrolled at 47 centers: 44% female, median age 59.4 years (range 0.6-81.3 years), 73% were non-Hispanic White, 10% Hispanic White, 8% Black, 5% Asian/Native Hawaiian/Pacific Islander, 0.5% American Indian/Alaska Native. Among the evaluable patients, 1181 received a HCT, 827 died, and 924 are still alive with or without HCT, with a median of 25 months of follow up (range=6-54 months [mos], inter-quartile range [IQR]=25-34 mos). The distribution was: 958 Very Likely, 517 Less Likely, and 276 Very Unlikely. Individuals in the Very Unlikely group were younger and were less likely to be non-Hispanic White. The unadjusted cumulative incidences of undergoing HCT by 6 mos and 2 years [yrs], in the Very Unlikely group were 51% and 61% vs. 60% and 69% in the Very Likely Group; after adjustment, there was not a significant difference in the likelihood of undergoing HCT (Dehn et al, submitted). There was no difference in median time from evaluability to HCT: 3.4 mos Very Unlikely and 3.3 mos Very Likely. Unadjusted survival rates from the time of evaluability for the Very Unlikely and the Very Likely groups were: 6 mos (85% vs 84%), 1 yr (69% vs. 69%) and 2 yrs (55% vs. 56%). In the multivariate Cox model, there was no significant difference in the risk of death (HR = 1.07 for Very Unlikely vs. Very Likely, 95% confidence interval 0.86-1.33, p=0.56) adjusting for significant clinical covariates: age, KPS, disease status, and time from consent to evaluability were all significantly associated with overall survival. There was no significant center effect and no interaction between donor search prognosis group and clinical covariates. Conclusion: In this large multicenter BMT CTN study, using the donor selection strategy described, there was no difference in adjusted time to HCT or survival for patients Very Likely versus Very Unlikely to find an 8/8 MUD. These results suggest that patients Very Unlikely to identify a MUD should proceed to HCT using the best available alternative donor rather than delaying HCT to try to identify a MUD.

Abstract Social determinants of health, including poverty, contribute significantly to health outcomes in the United States; however, their impact on pediatric hematopoietic cell transplantation (HCT) outcomes is poorly understood. We aimed to identify the association between neighborhood poverty and HCT outcomes for pediatric allogeneic HCT recipients in the Center for International Blood and Marrow Transplant Research database. We assembled 2 pediatric cohorts undergoing first allogeneic HCT from 2006 to 2015 at age ≤18 years, including 2053 children with malignant disease and 1696 children with nonmalignant disease. Neighborhood poverty exposure was defined a priori per the US Census definition as living in a high-poverty ZIP code (≥20% of persons below 100% federal poverty level) and used as the primary predictor in all analyses. Our primary outcome was overall survival (OS), defined as the time from HCT until death resulting from any cause. Secondary outcomes included relapse and transplantation-related mortality (TRM) in malignant disease, acute and chronic graft-versus-host disease, and infection in the first 100 days post-HCT. Among children undergoing transplantation for nonmalignant disease, neighborhood poverty was not associated with any HCT outcome. Among children undergoing transplantation for malignant disease, neighborhood poverty conferred an increased risk of TRM but was not associated with inferior OS or any other transplantation outcome. Among children with malignant disease, a key secondary finding was that children with Medicaid insurance experienced inferior OS and increased TRM compared with those with private insurance. These data suggest opportunities for future investigation of the effects of household-level poverty exposure on HCT outcomes in pediatric malignant disease to inform care delivery interventions.

Abstract Acute lymphoblastic leukemia (ALL) and acute myelogenous leukemia (AML) are the two most common childhood leukemias. Novel drug therapies and allogeneic hematopoietic cell transplant (alloHCT) have improved ALL and AML treatment outcomes over the past two decades. However, alloHCT may be associated with significant morbidity and mortality that results in increased healthcare utilization. To date, no multi-center comparative effectiveness studies have been performed specifically evaluating alloHCT in children with ALL or AML. This study uses a novel methodology to investigate the hypothesis that matched sibling donor (MSD) alloHCT has significantly lower healthcare utilization compared to unrelated donor (URD) and that among URD, umbilical cord blood transplants (CBT) will have higher initial utilization but lower long-term utilization. Clinical and transplant outcomes data from the Center for International Blood and Marrow Transplant Research (CIBMTR) database were merged with inpatient resource utilization and standardized cost data from the Pediatric Health Information System (PHIS) database using a probabilistic merge methodology. This merged dataset contained U.S. patients age 1-21 years who received alloHCT for ALL or AML from 2004-2013 with comprehensive CIBMTR data at a PHIS reporting hospital. The primary outcomes of overall survival (OS), leukemia free survival (LFS), and inpatient resource utilization were evaluated using Kaplan-Meier analysis, Cox proportional hazards, and unadjusted Poisson regression analysis. Cost and resource comparisons for all donor types were made through day+100 and focused on URD only comparisons up to 2-year follow-up. Donor procurement costs were not directly included in this analysis. A total of 797 patients (54% of CIBMTR eligible patients and 89% of CIBMTR patients at PHIS centers) were successfully identified in both CIBMTR and PHIS; 433 had ALL and had 364 AML. LFS for ALL at 3 years was 68% for MSD, 53% for MUD, and 53% for CBT. The LFS in ALL was significantly impacted by donor type, age, disease status, and CMV (Table). The associated total costs were significantly higher for well-matched unrelated bone marrow (MUD) vs MSD at 100d ($246,149 vs $147,547, p<0.01), but CBT costs were not significantly higher compared to MUD at 100d ($275,673 vs $246,149, p=0.09). When median total costs per day were compared across donor source, findings were similar with well- MUD was significantly higher than MSD at 100d ($3,388/d vs $2,511/d, p=0.012), and no significant difference between CBT and MUD ($3,881/d vs $3,388/d, p=0.53). The corresponding average length of stay (ALOS) was 35 days for MUD, 34 days MSD, and 53 days CBT. Among URD alloHCT, median CBT costs per day were not significantly higher compared to MUD at 2yrs ($2,472/d vs $2,294/d, p=0.49). AlloHCT for AML had a 3-yr LFS of 56% for MSD, 46% for MUD, and 41% for CBT. LFS were significantly different by disease status and performance status (Table). The associated total costs were significantly higher for MUD at 100d than MSD ($259,293 vs $143,870, p<0.001), but CBT costs were not significantly higher compared to MUD at 100d ($301,160 vs $259,293, p=0.055). Comparisons of median total costs per day were similar, MUD vs MSD at 100d was significantly higher ($3,627/d vs $2,478/d, p<0.01), but CBT costs were not significantly higher compared to MUD at 100d ($3,891/d vs $3,627/d, p=0.95). The corresponding ALOS was 38 days for MUD, 35 days MSD, and 66 days CBT. Among URD alloHCT, median CBT costs per day were not significantly higher compared to MUD at 2yrs ($3,232/d vs $3,102/d, p=0.49). This study recapitulates previously published outcomes of alloHCT for acute leukemia AND adds key findings on the impact of alloHCT on inpatient resource utilization and costs. Specifically, MSD and MUD alloHCT provide similar survival outcomes; however, MSD alloHCT has a significant advantage in cost and resource utilization for both ALL and AML. Among URD transplants, CBT does not show any substantial survival or resource utilization advantage over MUD. Ongoing research will need to be performed to determine if the difference among URD alloHCT becomes significant with a larger sample size and/or beyond the 2 years following alloHCT. Table Table. Disclosures Pulsipher: Novartis: Consultancy, Other: Study Steering Committee; Jazz Pharmaceutical: Consultancy; Medac: Other: Housing support for conference; Chimerix: Consultancy. Hahn:Novartis: Equity Ownership; NIH: Research Funding.

Abstract Introduction: Current advances in allogeneic hematopoietic cell transplant (alloHCT) may warrant a paradigm shift in managing children with sickle cell disease (SCD). This study characterizes the clinical outcomes and health care utilization (HCU) of alloHCT for pediatric SCD. We hypothesize that early alloHCT will have improved clinical outcomes, and decreased HCU. Methods: The Center for International Blood and Marrow Transplant Research database was used to identify children 21 years or less with alloHCT for SCD in the United States. Patient data included comprehensive research forms (CRF) from 2000-13 and transplant essential data (TED) forms from 2000-11. CRFs provided clinical risk factors associated with overall survival, graft failure, grade III-IV acute GVHD, and GVHD related event free survival (GREFS) - the survival free of graft failure, chronic GVHD, or death. Risk factors included age, gender, performance status, year of alloHCT, prior SCD complications and therapy, CMV status, donor type, conditioning regimen, and GVHD prophylaxis. Due to low event rates and sample size, only univariate analysis of risk factors was performed. TED data was merged with Pediatric Health Information System (PHIS) inpatient data using a probabilistic merging algorithm to determine risk factors and clinical outcomes associated with HCU. Available PHIS adjusted cost data was used to determine the total adjusted cost for all inpatient admissions per patient per hospital day. To standardize these costs, the total adjusted cost per 30 hospital days was calculated for each patient and used as the primary HCU outcome. HCU outcomes were analyzed for the alloHCT year, day 0 to day +365. Results: CRF data for 161 patients showed an overall survival at 2 years of 90% (95% confidence intervals [CI] 85-95%): 96% (95% CI 89-100%) for related and unrelated cord blood transplant (CBT), 94% (95% CI 86-98%) matched siblings (MSD), and 74% (95% CI 54-90%) matched unrelated donors (MUD, p=0.002). All deaths occurred among children with pre-alloHCT complications of SCD, and deaths were due to organ failure (37.5%), infections (25%), GVHD (6.25%). Risk of death was significantly higher for children ≥10 years old (HR 21, p=0.003) and MUD compared to MSD (HR 5.88, p=0.005) but lower with cyclosporine A (CSA) GVHD prophylaxis versus FK506 (HR 0.33, p=0.031). 75% of deaths occurred before day +42. Cumulative acute GVHD incidence at day 100 was 14% (95% CI 9-20%)and was associated with age ≥10yrs (HR 2.63, p=0.035). Chronic GVHD incidence was 31% (95% CI 23-38%) at 2yrs, and factors associated were age ≥10yrs (HR 1.92, p=0.034), MUD vs MSD (HR 2.53, p=0.017), and CSA vs FK506 prophylaxis (HR 0.48, p=0.018). Chronic GVHD risk increased significantly after 2006 (HR 2.81, p=0.018). The 2yr GREFS was 64% (95% CI 56-71%). Age ≥10yrs (HR 2.2, p=0.005), MUD (vs MSD, HR 3.00, p=0.002) and CSA prophylaxis (vs FK506, HR 0.49, p=0.011) were significantly associated with this outcome. Among the 175 patients with combined TED and PHIS data, the median total adjusted cost was $117,393 per 30 hospital days per patient (range: $36,244-$515,640) during the alloHCT year with a median of 53 hospital days per patient (range: 16-304). Age ≥10yrs and HCU were not significantly associated (p=0.775). MSD had the lowest HCU compared to CBT and unrelated transplants (p<0.001). CBT and peripheral blood stem cells were associated with higher HCU compared to bone marrow (p=0.004). Increased HCU was associated with prior stroke (p=0.0004) and pain crises (p=0.0094) but not acute chest syndrome (p=0.2913). Overall SCD complication and severity indices correlated with increased HCU (p=0.052, p=0.0219, respectively). Conclusions: AlloHCT outcomes in children with SCD were linked to age and donor type suggesting that early alloHCT before age 10 years is preferred. Specifically, SCD severity and MUD alloHCT are associated with poorer outcomes and increased HCU. This supports the recommendation of early alloHCT, prior to onset of SCD complications, for children with SCD and an available MSD. Donor source and type had a significant impact on both outcomes and HCU. CBT outcomes were similar to MSD bone marrow; yet CBT had higher HCU suggesting additional analysis is needed to determine if the clinical benefit outweighs the cost. Further analysis is also needed to better understand and mitigate risk factors associated with poor outcomes and increased HCU following MUD alloHCT. Disclosures Arnold: Robert Wood Johnson Foundation Harold Amos Medical Faculty Development Program: Other: award. Hahn:NIH/NHLBI: Research Funding; Novartis: Equity Ownership.