HCT-CI Score Research Articles

Evaluation of risk for bronchiolitis obliterans syndrome after allogeneic hematopoietic cell transplantation with myeloablative conditioning regimens.

Bronchiolitis obliterans syndrome (BOS), as chronic manifestation of graft-versus-host disease (GVHD), is a debilitating complication leading to lung function deterioration in patients after allogeneic hematopoietic cell transplantation (allo-HCT). In the present study, we evaluated BOS development risk in patients after receiving myeloablative conditioning (MAC) regimens. We performed a retrospective analysis of patients undergoing allo-HCT, who received MAC with busulfan/cyclophosphamid (BuCy, n = 175) busulfan/fludarabin (FluBu4, n = 29) or thiotepa/busulfan/fludarabine (TBF MAC, n = 37). The prevalence of lung disease prior allo-HCT, smoking status, GvHD prophylaxis, HCT-CI score, EBMT risk score and GvHD incidence varied across the groups. The cumulative incidence of BOS using the NIH diagnosis consensus criteria at 2 years after allo-HCT was 8% in FluBu4, 23% in BuCy and 19% in TBF MAC (p = 0.07). In the multivariate analysis, we identified associated factors for time to BOS such as FEV1<median (99% of predicted) (HR = 2.39, p = 0.004), CMV patient serology positivity (HR = 2.11, p = 0.014), TLC < 80% of predicted (HR = 0.12, p = 0.02) and GvHD prophylaxis with in vivo T-cell depletion (HR = 0.29, p = 0.001) as predictors of BOS. In summary, we identified risk factors for BOS development in patients receiving MAC conditioning. These findings might serve to identify patients at risk, who might benefit from closely monitoring or early therapeutic interventions.

Understanding factors limiting hematopoietic cell transplantation for acute myeloid leukemia patients in Mexico: a comprehensive analysis.

Acute myeloid leukemia (AML) is the most frequent indication for allogeneic hematopoietic cell transplantation (alloHCT) worldwide; social and health system barriers limit its access. We performed an observational retrospective analysis in Mexico to analyze factors limiting alloHCT in fit patients with AML. With a median follow-up of 11.8 months, 301 patients were included, with a median age of 42; 33.5% were classified as adverse risk. Despite 215 patients (92.5%) achieving complete remission, only 103 (34%) had HLA-typing: 44.5% had a matched-sibling donor (MSD), 32% a haploidentical donor, and 23.5% had no donor. Only 23.5% of patients had an HCT consult; merely 36 underwent an HCT: 30 alloHCT, and six an autologous HCT. Age ≥ 60 years, HCT-CI score ≥ three, and the absence of a local transplant program negatively influenced HLA typing likelihood. Patients with an MSD had a higher alloHCT likelihood. The cumulative incidence of transplant (CIT) and relapse (CIR) at 6 and 12 months was 7.3% and 13.8%, 8.2% and 13%, respectively. A lack of HLA-typing was associated with a lower CIT (p < 0.001) and higher CIR (p = 0.033) (HR 11.72, CI 95% 4.39-31.27, p < 0.001), while the presence of an MSD was associated with a higher CIT (p = 0.002) (HR 4.22, CI 95% 1.89-9.44, p < 0.001). The main reasons hindering alloHCT are the lack of access to HLA-typing tests and the absence of an MSD. A national donor registry and improved HLA-typing accessibility are critical for increasing alloHCT access in Mexico.

Surrogates of Endothelial Injury Predict Survival After Post-transplant Cyclophosphamide

Post-transplant cyclophosphamide (PT-Cy) is becoming the standard of care for preventing graft-versus-host disease (GVHD) following allogeneic hematopoietic stem cell transplant (alloHCT). Cyclophosphamide is associated with endothelial injury. We hypothesized that the endothelial activation and stress index (EASIX) score, being a marker of endothelial dysfunction, will predict non-relapse mortality (NRM) in alloHCT patients receiving PT-Cy for GVHD prophylaxis. We evaluate the prognostic ability of the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) and EASIX scores, and report other factors influencing survival, in patients with hematologic malignancies undergoing alloHCT and receiving PT-Cy-based GVHD prophylaxis. Adult patients with hematologic malignancies who underwent alloHCT and received PT-Cy for GVHD prophylaxis at the three Mayo Clinic locations were included in this study. We retrospectively reviewed the Mayo Clinic database and the available electronic medical records to determine the patient, disease, and transplant characteristics. An HCT-CI score of ≥3 was considered high. The EASIX score was calculated from labs available between day -28 (of alloHCT) to the day of starting conditioning and analyzed on log2 transformed values. A log2-EASIX score ≥2.32 was considered high. The cumulative incidence of NRM was determined using competing risk analysis, with relapse considered as competing risk. Overall survival (OS) from transplant was determined using Kaplan-Meier and log-rank methods. Cox-proportional hazard method was used to evaluate factors impacting survival. A total of 199 patients were evaluated. Patients with a high log2-EASIX score had a significantly higher cumulative incidence of NRM at 1 year after alloHCT (34.5% versus 12.3%, P = .003). Competing risk analysis showed that a high log2-EASIX score (HR 2.92, 95% CI 1.38 to 6.17, P = .005) and pre-alloHCT hypertension (HR 2.15, 95% CI 1.06 to 4.36, P = .034) were independently predictive of 1 year-NRM. Accordingly, we combined the two factors to develop a composite risk model stratifying patients in low, intermediate, and high-risk groups: 111 (55.8%) patients were considered low-risk, 76 (38.2%) were intermediate and 12 (6%) were high-risk. Compared to patients in the low-risk group, the intermediate (HR 2.38, 95% CI 1.31 to 4.33, P = .005) and high-risk (HR 5.77, 95% CI 2.31 to 14.39, P < .001) groups were associated with a significantly inferior 1-year OS. Multiorgan failure (MOF) was among the common causes of NRM (14/32, 43.8%) particularly among patients with prior pulmonary comorbidities [7 (50%) patients]. Our study shows that EASIX score is predictive of survival after PT-Cy. The novel EASIX-HTN composite risk model may stratify patients prior to transplant. MOF is a common cause of NRM in patients receiving PT-Cy, particularly among patients with pulmonary comorbidities.

Treatment of acute myeloid leukemia with Orca-T.

6552 Background: Allogeneic hematopoietic stem cell transplants (alloHSCT) offer a potential curative treatment for many hematological cancers, however, traditional alloHSCT is associated with high mortality from complications including infection, graft versus host disease (GvHD) and relapse. Orca-T is an investigational allogeneic T-cell immunotherapy that includes stem and immune cells, derived from allogeneic donors, that leverages highly purified, polyclonal donor regulatory T cells to control alloreactive immune responses. In this sub-group analysis, we evaluated the safety and efficacy of patients with acute myeloid leukemia who were treated with Orca-T. Methods: Data from 37 patients with the diagnosis of acute myeloid leukemia (AML) in CR/CRi who received myeloablative conditioning with busulfan, fludarabine, and thiotepa (BFT) followed by Orca-T by 6/30/22 as part of a multicenter phase 1b single-arm trial (NCT04013685) are reported here. Patients enrolled in the phase 1b trial who did not meet these criteria were not included in this analysis. Patients received BFT prior to Orca-T, followed by single-agent GvHD prophylaxis with tacrolimus, and had an 8/8 related or unrelated matched donor. Donors were matched via DNA-based high-resolution typing of HLA-A, -B, -C, and -DRB1. Results: Orca-T was successfully manufactured at a centralized GMP facility, distributed, and infused at study sites throughout the U.S. Vein-to-vein time (i.e. time between end of donor apheresis to start of recipient’s Orca-T infusion) was &lt; 72 hours for all patients, with the majority &lt; 60 hours. Median age was 51 years, 49% were female and 16% were of Hispanic or Latino ethnicity. Twenty-three (62%) had matched related donors and 14 (38%) had matched unrelated donors. Baseline HCT-CI score was 3 and 4 in 27% and 8% of the patients, respectively. The majority had intermediate DRI scores (89%) and 41% were MRD positive at baseline. The median duration of follow-up was 14 months. Relapse-free survival at 12 months was 81.4% (95% CI: 62.9, 91.2). Non-relapse mortality and overall survival were 0% and 100% at 12 months, respectively. Conclusions: These encouraging results suggest that investigational Orca-T could represent a reduced toxicity alternative to conventional alloHSCT. This combination of Orca-T with myeloablative BFT led to &gt; 80% RFS without treatment related mortality, and 100% overall survival in this AML patient population. These outcomes were accomplished with consistent and reliable cell manufacturing and distribution of Orca-T at a national scale. A multi-center randomized controlled phase 3 trial comparing Orca-T to SOC, utilizing BFT or TBI-based conditioning, will complete enrollment during the first half of 2024. (NCT05316701). Clinical trial information: NCT04013685 .

Hematopoietic stem cell transplant for adults with mixed phenotypic acute leukemia.

6517 Background: Mixed phenotype acute leukemia (MPAL) is a rare acute leukemia subtype characterized by expression of lymphoid and myeloid lineage markers on blasts. Consequently, the role of hematopoietic stem cell transplant (HCT) consolidation is unclear. We conducted a retrospective study of MPAL patients treated at our institution integrating the impact of transplant status, chemotherapy, and initial response on survival. Methods: We evaluated patients with MPAL at Fred Hutchinson Cancer Center from 1/2005 – 9/2022, some of whom were previously reported (Huang et al, ASH 2023). Independent pathology review using 2022 WHO criteria verified MPAL diagnosis. Potentially transplant eligible patients were defined as those &lt;75 years of age, diagnosed at least 6 months prior to data retrieval date, and alive 100 days after diagnosis with an evaluable induction response. Log-rank and Cox proportional hazard models were used to compare survival and adjust for baseline covariates. Survival was landmarked at 100 days. Results: Of 55 total patients, 42 were potentially HCT eligible and 30 received HCT (71.4%; 20/30 myeloablative). Patients who did not complete HCT were similar in age (median 46.2, range 18-70 vs median 50.3, range 24 – 74, p = ns) and had similar ECOG (ECOG 0-1 86.6% vs 75.0%, p = ns) at diagnosis. Nine of 12 non-transplanted patients had age-adjusted HCT-CI score ≤ 3. Patients receiving a HCT had better progression free survival (PFS) (p = 0.025) and were more likely to be alive at 48 months (61.6% vs. 32.4%, p = 0.011) with a median overall survival (mOS) of not reached (NR) (95% CI, 43 months – NR) compared to a mOS of 13 months (95% CI, 9 months – NR) for those not transplanted. Given that our prior work showed that the type of induction chemotherapy did not influence OS (p = 0.40) or remission status (p = 0.16) (Huang et al. ASH 2023), we investigated impact of remission status at the time of transplant. Differences in PFS and OS persisted when stratifying patients by induction response status with HCT status (PFS p = 0.0048; OS p &lt; 0.0001). Patients who had a complete response (CR) followed by HCT had the longest mOS = NR (17 of 24 patients alive after 48 mo). Patients who had resistant disease (RD) and completed HCT had mOS = 43 months (95% CI, 43 months– NR). Patients who achieved CR but did not undergo HCT had mOS = 19 months (95% CI, 11 months – NR). Patients who had RD and did not undergo HCT had median OS of 6 months (95% CI, 6 – NR). The hazard ratio for death among patients who underwent HCT was 0.28 (95% CI 0.077 – 0.99, p = 0.049). Conclusions: HCT consolidation was significantly correlated with improved survival (p = 0.011). While potentially biased by selection and limited by small sample size, patients benefitted from undergoing a HCT regardless of response to prior therapy (p &lt; 0.0001). This study suggests that patients with MPAL in CR after induction chemotherapy as well as those with less than complete responses should be considered for HCT consolidation.

Identifying risk factors for severe omicron infection in allogeneic hematopoietic stem cell transplant recipients with hematologic malignancies.

In December 2022, a large-scale epidemic occurred in China due to Omicron variant of SARS-CoV-2. This study explored risk factors for Omicron infection in transplant recipients at our institution and investigated the factors influencing the severity of SARS-CoV-2 Omicron infection among recipients of allo-HSCT. This single-center study investigated totally 63 allogeneic hematopoietic stem cell transplant patients infected with Omicron variant at the Beijing GoBroad Boren Hospital Transplant Center during December 2022 and analyzed their risk factors. The study included 63 allogeneic hematopoietic stem cell transplant patients who developed Omicron infection. There were 34 mild and 29 moderate to severe cases. Their median age was 22 years (range, 1-65 years), with the male-to-female ratio being 1:1.1. Acute myeloid leukemia (53.97%), acute lymphoblastic leukemia (42.86%), and non-Hodgkin lymphoma (3.17%) were underlying diseases. The median time between HCT and Omicron infection was 8.45 months. Significant predictive factors for moderate to severe Omicron infection included older age (p < .0001), cGVHD (p = .0195), concurrent bacterial infection (p < .0001), low absolute lymphocyte count (p = .026), low CD4/CD8 ratio (p = .0091), high CRP (p < .0001), high serum ferritin (p = .0023), high D-dimer (p < .0001), low CD4 absolute count (p = .0057), and low B-cell absolute count (p = .0154). A moderate to high HCT-CI score tended to be associated with moderate to severe infection (p = .0596). This study indicates that risk factors for severe Omicron infection include certain clinical characteristics, such as age, cGVHD, and inflammatory response.

Effect of pre-transplant functional status on length of hospital stay in patients undergoing allogeneic hematopoietic stem cell transplant in an outpatient transplant program.

6560 Background: The use of reduced intensity conditioning regimens including non-myeloablative regimens in allogeneic hematopoietic stem cell transplant (allo SCT), has expanded the pool of transplant candidates in the United States. Nonetheless, allo SCT, is associated with significant morbidity and mortality especially in patients 65 and older. In our outpatient transplant program, allo SCT patients undergo a comprehensive physical and occupational therapy (PT/OT) evaluation pre-transplant. Methods: We retrospectively reviewed all patients undergoing an allo SCT between January 2019 and December 2022 who had a PT/OT evaluation pre-transplant. We analyzed lower extremity functional scale (LEFS) and fatigue score (FACIT). The FACIT score is a patient reported outcome tool where the lower the score, the less fatigue impacts a patient’s performance. Results: We identified 218 patients who had at least one variable reported. Eighty-one patients were 65 years of age or older. All patients in the 65 and older group had a RIC or NMA conditioning regimen. In the 65 and older group, 72.8% had an HCTCI score of 3 or more compared to 59.1% in the group younger than 65. In patients younger than 65, those who had a lower LEFS (ie less lower extremity strength), had a statistically significant longer hospital stay of 15.5 days compared to 9 days (p=0.003). In patients 65 and older, lower FACIT scores (ie less patient reported fatigue), resulted in a statistically significant shorter hospital stay of 7.5 days compared to 13 days (p=0.019). In addition, there was a trend towards shorter hospital stays in patient 65 and older who had a higher LEFS of 5 days compared to 12.5 days (p=0.07). There was no difference in survival outcomes but there was a trend towards better overall survival in patients 65 and older with high LEFS (p=0.08) and a trend towards better NRM in this group (p=0.11). Conclusions: Our study highlights the need for comprehensive assessments in patients undergoing allo SCT. Geriatric functional status assessments are necessary to determine patients at risk for complications and to optimize such patients with exercise and cognitive rehabilitation programs prior to allo SCT. [Table: see text]

Post-transplant cyclophosphamide at 80 mg/kg with low dose post-engraftment anti-thymocyte globulin in haploidentical transplantation with myeloablative conditioning.

While post-transplant cyclophosphamide (PTCy) is commonly used as graft-versus-host disease (GvHD) prophylaxis in haploidentical stem cell transplantation (haplo-HSCT), its dose remains a matter of debate due to side effect concerns. Standard dose of 100 mg/kg associated with tacrolimus and post-engraftment anti-thymocyte globulin (ATG) was used as the reference GvHD prophylaxis in our center and had demonstrated encouraging results. Though PTCy 80 mg/kg was shown to be feasible in patients in reduced-intensity conditioning, whether it exerts equivalent GvHD prophylactic efficacy in myeloablative conditioning (MAC) setting has not been confirmed. Here, we retrospectively analyzed the efficacy and safety of PTCy 80 mg/kg combined with tacrolimus and post-engraftment ATG as GvHD prophylaxis in patients aged more than 55 years or with cardiac antecedents or HCT-CI score >2 undergoing haplo-HSCT with MAC. The cumulative incidence of grade III-IV aGvHD at day 100 and moderate-to-severe cGvHD at 1 year was 4.8% ± 3.4% and 19.9% ± 7.0%, respectively. When compared with patients receiving the reference regimen, patients from the PTCy 80 mg/kg group had similar incidence of GvHDs and survival as their younger counterparts. Thus, PTCy 80 mg/kg seems to be feasible for patients treated with MAC conditioning regimens in haplo-HSCT, inviting further investigation notably in frail patients.

Lisocabtagene Maraleucel Versus Axicabtagene Ciloleucel: Efficacy and Toxicity in a Real-World Setting

CD19 CAR-T therapy has revolutionized the management of high-risk and relapsed/refractory (R/R) large B-cell lymphoma (LBCL) but remains limited by significant toxicities leading to morbidity/mortality and high resource utilization. Single-arm studies have suggested differences in efficacy and toxicity across FDA-approved CD19 CAR-T products. A matching-adjusted indirect treatment comparison showed comparable efficacy and more favorable safety with lisocabtagene maraleucel (liso-cel) compared to axicabtagene ciloleucel (axi-cel), but was limited to clinical trial patients (pts) and suffered from an absence of patient-level data (Maloney, J Hematol Oncol, 2021). In the absence of randomized clinical trial data, adjusted comparative analyses using pt-level data are critically needed to guide product choice. Therefore, we retrospectively evaluated the impact of CAR-T product type on the outcomes of 129 LBCL pts receiving liso-cel or axi-cel per standard of care. All LBCL pts treated at our center with liso-cel or axi-cel outside of a clinical trial between 1/2018 and 5/2023 were included. Best response was determined within 3 months of CAR-T infusion by PET-CT imaging per Lugano 2014 criteria. Cytokine release syndrome (CRS) and immune-effector cell-associated neurotoxicity syndrome (ICANS) were graded using ASTCT criteria. Of 129 total pts, 37% (n=48) and 63% (n=81) received liso-cel and axi-cel, respectively. Seven pts received out-of-specification liso-cel on an expanded access protocol. Pts who received liso-cel were older (median 67 vs 62 years, p=.003). Other baseline characteristics, including male sex (liso-cel vs axi-cel: 63% vs 69%, p=.4), HCT-CI score (1.0 vs 1.0, p=.6), pre-lymphodepletion (LD) LDH (178 vs 214 U/L, p=.14) and ALC (0.65 vs 0.60 x 10³/µL, p=.3), largest lesion diameter (3.1 vs 3.0 cm, p=.4), and extranodal disease (56% vs 56%, p&amp;gt;.9) were similar. The vein-to-vein time (time from leukapheresis to CAR-T infusion) was longer for liso-cel: median, 35 vs 27 days (p&amp;lt;.001). After liso-cel, the total inpt duration was shorter (median, 5 vs 14 days, p&amp;lt;.001) and fewer pts had ≥2 admissions (8.3% vs 22%, p=0.043). In pts with measurable disease prior to LD (n=113), we observed comparable efficacy with liso-cel vs axi-cel: ORR, 82% vs 77% (p=.5); CR, 56% vs 51% (p=.8). After a median follow-up of 17.7 months, we observed comparable 1-year outcomes with liso-cel vs axi-cel: duration of response (DOR), 56% vs 61% (p=.7); progression-free survival (PFS), 47% vs 47% (p=.99; Figure); and overall survival (OS), 69% vs 60% (p=.39). In pts evaluable for toxicity assessment (n=129), liso-cel was associated with lower rates of CRS and ICANS compared to axi-cel: any grade CRS, 62% vs 88% (p=.001); ICANS any grade, 32% vs 56% (p=.010); days with fever, median 2 vs 5 days (p&amp;lt;.001). Grade 3-4 CRS, 2.1% vs 9.9% (p=.2) or grade 3-4 ICANS, 23% vs 19% (p=0.5) were similar. We measured lower peak serum inflammatory markers after liso-cel: CRP, 58 vs 114 mg/L (p&amp;lt;.001); ferritin, 622 vs 1,315 ng/mL (p=0.007); IL-6, 55 vs 204 pg/mL (p=.010); and D-dimer, 1.4 vs 2.4 mg/L (p=.017). The incidence of infectious complications after liso-cel vs axi-cel was as follows: bacteremia: 6% vs 9% (p=.7); CMV viremia: 13% vs 6.2% (p=.3). Post-infusion median nadir cytopenias were less severe after liso-cel: ANC, 0.32 vs 0.04 x 10³/µL (p&amp;lt;.001); Plt, 69 vs 35 x 10³/µL (p=.003); and Hgb, 8.9 vs 8.2 g/dL (p&amp;lt;.001). Fewer pts developed severe neutropenia after liso-cel: 72% vs 93% (p=0.002). In multivariable analysis including pre-LD LDH and ALC, largest lesion diameter, age and HCT-CI score, we could not confirm an independent impact of the product type on CR, PFS, or OS ( Table). However, axi-cel remained independently associated with a higher odds of any grade CRS (adjusted OR [aOR] 4.56, 95% CI 1.65-13.5, p=.004) and any grade ICANS (aOR 3.44, 95% CI 1.42-8.85, p=.008). Our analysis of CD19 CAR-T therapy for R/R LBCL in the non-trial setting showed similar rates of durable responses following liso-cel and axi-cel. Pts who received liso-cel were older, with otherwise comparable baseline characteristics. Although liso-cel was associated with less toxicity, its vein-to-vein time was longer. In multivariable analyses, pre-LD LDH and largest lesion diameter were the only factors independently associated with response outcomes. We conclude that liso-cel is a robust alternative to other CD19 CAR-T products in older and frailer LBCL pts.

Assessing the Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) in Risk-Stratifying Multiple Myeloma Patients for Autologous Stem Cell Transplantation

Background: Hematopoietic stem cell transplant (SCT) is a high-intensity treatment that can cause psychological distress. Pre-transplant psychosocial screening is commonly used to assess mental health, social support, compliance, and health behaviors in HCT centers. However, the optimal standardized approach to psychosocial screening is still being defined. Some studies have shown that pre-transplant psychosocial assessments can predict overall survival (OS) after SCT, while others have found associations with non-relapse mortality (NRM) but not with OS. Single-institution reports consistently indicate that pre-HCT psychosocial assessments are associated with the length of SCT hospitalization and readmission rate. The Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) is an established tool in the solid organ transplant field that can be used to assess and quantify psychosocial risk, that can help in patient selection and pre-transplant preparation. Objective: This study aimed to validate the SIPAT as a standardized psychological assessment in patients with multiple myeloma (MM) undergoing autologous SCT (ASCT). The primary goal was to analyze the impact of psychosocial risk, as measured by the SIPAT score, on the length of hospital stay and readmission rates within 100 days post-discharge. Secondary outcomes included the risk of infections, progression-free survival (PFS), and overall survival (OS). Methods: This retrospective, single-center study included 87 patients with MM who underwent ASCT between 2019 and 2022 at University Hospitals Seidman Cancer Center. Patient and disease characteristics were collected, and SIPAT scores were recorded for all patients. Patients were grouped based on their SIPAT scores as “Excellent” (score ≤ 6) or “Good” (score &amp;gt; 6). Hospitalization duration during transplant, readmissions, and infections within the first 100 days after ASCT were used as indicators of treatment-related toxicity. Results: 30 patients had an “Excellent” SIPAT score (mean score: 3.47, SD 1.81), while 57 had a “Good” score (mean score: 11.81, SD 5.92). Both groups exhibited similar sex and race distribution, BMI, and KPS scores. The “Excellent” SIPAT group had more patients with HCT-CI scores of 0-2. Both groups had comparable ISS staging and high-risk cytogenetics, along with similar prior lines of treatment and disease status at the time of transplant. Patients in the “Good” SIPAT score group had a higher number of CD34+ cells infused per kg. No significant differences were observed between the groups in terms of engraftment time, hospitalization duration, or rates of hospitalizations and infections within the first 100 days after transplant. Univariate analysis of risk of readmissions showed that BMI had a significant effect (HR 1.09, 95% CI 1.02-1.16, p=0.009) for each unit increase and HCT-CI had a significant effect (HR 5.56, 95% CI 1.39-22.24, p=0.015) for HCT-CI score 3+ compared to 0-2. However, in the multivariable model, these effects did not persist. Conclusions: Although the SIPAT tool is widely used for evaluating different organ transplants, including HCT, a high SIPAT score alone may not be sufficient to risk-stratify candidates for ASCT in MM. Further research and evaluation are warranted to better understand the true predictive value of pre-transplant psychosocial assessments.

Outcomes of CAR-T Cell Therapy for Large B Cell Lymphoma in Patients of 70 Years and Older: Multicentric Experience on Behalf of Geth-TC/Geltamo

Background: Median age at diagnosis of diffuse large B cell lymphoma (DLBCL) patients is 66 years; 40% of patients are diagnosed at an age greater than 70 years. CAR-T cell therapy is approved for the treatment of relapsed/refractory DLBCL patients; however, a deeper understanding of outcomes in patients older than 70 years is needed. Our aim was to analyze outcomes of CAR-T cell therapy in this population and compare them to those obtained in younger patients in the real-world setting. Methods: A subgroup analysis of our real life experience report (Kwon, Iacoboni et al. Haematologica 2022) was performed. Data from consecutive patients treated in Spain with commercial CAR-T products were retrospectively collected on behalf of GETH-TC (Spanish Group of Stem Transplantation and Cell Therapy)-GELTAMO (Spanish Group of Lymphoma and Autologous Stem Cell Transplantation). Patients infused between November-2018 and August-2021 were included. Last update of the cohort was performed in June 2023. Cytokine release syndrome (CRS) and Immune effector cell-associated neurotoxicity syndrome (ICANS) were graded using the ASTCT consensus criteria. Response was assessed according to the Lugano criteria. Results: Characteristics of the patients are summarized in Table 1. A total of 307 patients underwent apheresis for CAR-T cell therapy as 3 rd or subsequent line of therapy. Fifty-four (18%) patients were 70 years or older. There were no differences between groups regarding product selection, proportion of patients infused, production failure and rate of bridging therapy. There were more patients with HCT-CI score ≥3 and a trend of higher proportion of patients with ECOG &amp;gt;2 at apheresis in the older group (31% vs. 19%, p=0.047; 9% vs. 5%, p=0.054); the remaining baseline characteristics did not differ. A similar proportion of patients were infused. Among the infused population (n=261), median time from apheresis to infusion was 49 days for patients ≥70 years (n=45) and 47 for younger patients (n=216) (p=0.824). A similar proportion of patients developed any grade of CRS and ICANS (88% vs. 80%, p=0.132 and 31% vs. 29%, p=0.843) and grade 3-4 events (11% vs. 6.5%, p=0.277 and 18% vs. 10%, p=0.146). Median duration of CRS (4 and 5 days, p=0.150), ICANS (4 and 5 days, p=0.540) and hospitalization length (20 days for both groups, p=0.995) did not differ between groups. There were not significant differences in the proportion of patients admitted to ICU (24% vs. 18%, p=0.284); however, the proportion of patients developing infection in the first 6 months after infusion showed a trend to be higher in the older group (42% vs. 29%, p=0.099). Non-relapse mortality was similar between groups (13% vs. 7%, 9=0.24). With a median follow-up of 19.2 months from infusion, both 12-m PFS (30% vs. 38%, p=0.281) and 12-m OS (49% vs. 54%, p= 0.473) were similar between older and younger patients (Figure 1). In the multivariate analysis of the whole population including CAR-T type, disease characteristics (primary refractory, progressive disease, disease stage, R-IPI and high LDH at apheresis), ECOG ≥2 and age ≥70, high LDH (HR 2.1, p=0.001), disease stage III-IV (HR 1.8, p=0.038) and ECOG ≥2 (HR 2, p=0.025) were risk factors for EFS. Age ≥70 (HR 1.5, p=0.054) and progressive disease at lymphodepletion (HR 1.8, p=0.055) were nearly significant risk factors. In the multivariate analysis for OS, high LDH (HR 1.7, p=0.013), high R-IPI (1.2, p=0.039), ECOG ≥2 (HR 2, p=0.014) and progressive disease at lymphodepletion (HR 1.9, p0.042) were risk factors for OS, while age had no impact (HR 1.1, p=0.674). Conclusions: In our real-life experience, CAR-T cell therapy showed a similar efficacy and safety in younger and older patients (&amp;gt;70 years). Consequently, this latter group should receive CAR-T cell therapy if treatment criteria are met.

A Single Center Retrospective Study on the Efficacy of Haploidentical Hematopoietic Stem Cell Transplantation in Patients with Myeloid Neoplasms over 50 Years Old

Objective: This study aims to evaluate the efficacy and safety of haploidentical hematopoietic stem cell transplantation in patients with myeloid neoplasms over 50 years old, and to compare the differences in survival, recurrence, and adverse reactions between patients aged 50-55 and over 55 years old. Methods: The patients with myeloid neoplasms over 50 years old who received haploidentical hematopoietic stem cell transplantation from November 2016 to December 2021 in the Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University, School of Medicine were enrolled. According to the age at the time of transplantation, patients were divided into Group A (50-55 years old) and Group B (≥ 55 years old). The differences in Overall survival (OS), progression free survival (PFS), non-relapse mortality (NRM), cumulative incidence of relapse (CIR), incidence of graft versus host disease (GVHD), and infection rate between the two groups were analyzed. Results: A total of 163 patients (group A, n=77; group B, n=86) were enrolled, including 112 cases of acute myeloid leukemia (AML), 39 cases of myelodysplastic neoplasms (MDS), 4 cases of chronic myeloid monocyte leukemia (CMML), 3 cases of primary myelofibrosis (MF), and 5 cases of chronic myeloid leukemia (CML). There were no statistically significant differences in baseline data between the two groups, including follow-up time, disease categories, HCT-CI score, remission status of AML patients, minimal residual lesion (MRD) level of AML patients, and IPSS-R score of MDS patients. However, more patients in Group A received myeloablative (MAC) conditioning than patients in Group B (92.2% vs 50%, P=0.000). The median follow-up time was 741 (7-2377) days. The overall 2-year OS is 73.0% ± 3.5%, 2-year PFS is 71.3% ± 3.6%, 2-year NRM is12.23%（7.65%-17.93%）, and 2-year CIR is 17.20%（11.64%-23.69%）. All patients in group A achieved hematopoietic reconstitution except one patient died of graft failure, while 5 patients of group B died of graft failure(P=0.126). Neutrophils and platelet reconstruction in Group B was slightly longer than in Group A. The neutrophils reconstruction occurred at a median of 12 (8-20) day and 13 (9-25) day, respectively (P=0.007), and platelet reconstruction occurred at a median of 12 (9-28) day and 13 (8-37) day, respectively (P=0.055). The 2-year OS of Group A and Group B was 76.6% ± 4.8% and 69.0 ± 5.1%, respectively (P=0.199); The 2-year PFS was 76.2% ± 4.9% and 66.9 ± 5.1%, respectively (P=0.236); The 2-year NRM was 9.16% (4.00% -16.96%) and 18.61% (11.18% -27.51%), respectively (P=0.094); The 2-year CIR was similar, with 14.66% (7.74% -23.67%) and 19.16% (11.48% -28.33%), respectively (P=0.782). Interestingly, there was a difference in NRM between patients receiving reduced-intensity (RIC) and MAC conditioning in Group B, which was 10.2% (3.69% -20.61%) and 25.58% (13.64% -39.34%), respectively (P=0.043), while there was no difference in CIR, which was 17.31% (7.88% -29.80%) and 18.90% (8.71% -32.06%), respectively (P=0.933). It is suggested that in older patients, the strength of conditioning regimen has a greater impact on NMR. The incidence of grade 3-4 aGVHD within 100 days in all patients was 11.84% (7.31% -17.56%), and the incidence of 2-year intensive cGVHD was 8.19% (4.58% -13.14%). The incidence of grade 3-4 aGVHD within 100 days was similar between the two groups, with 9.46% (4.13% -17.46%) and 14.10% (7.46% -22.81%) (P=0.368), respectively. The 2-year intensive cGVHD was 8.07% (3.26% -15.72%) and 8.28% (3.62% -15.42%) (P=0.890), with similar incidence rates. The incidence of bacterial septicemia, pneumonia, invasive fungal infection, herpes virus and other infections were similar in both groups. Univariate and multivariate analysis both showed that 50-55 years old was an independent protective factor of OS (2.384 (1070-5.312), P=0.034) and GRFS (2.683 (1.181-6.094), P=0.018) in AML patients. Conclusion: Haploidentical hematopoietic stem cell transplantation is an effective and safe treatment for myeloid neoplasms over the age of 50. Compared with patients aged 50 to 55 years old, patients with myeloid neoplasms aged over 55 years old had similar efficacy and safety. The impact of MAC and RIC pretreatment on the prognosis of patients at different ages may be different. This retrospective study is limited in number and needs more cases and prospective cohort study to further verify.

Comparison of Myeloablative Conditioning with Cyclophosphamide and Total-Body Irradiation (Cy/TBI) Vs. Fludarabine, Melphalan, and Total-Body Irradiation (Flu/Mel/TBI) in Patients Undergoing Allogeneic Stem Cell Transplant for AML/ALL

Background: Cyclophosphamide combined with total-body irradiation (Cy/TBI) has been widely used worldwide as the standard myeloablative conditioning (MAC) for allogeneic stem cell transplantation (allo-HCT), but there are concerns about the antitumor effects of CY, as well as side effects, including cardiotoxicity and mucosal toxicity. A few studies suggest that the addition of an anticancer agent to a Cy/TBI regimen may reduce recurrence rates, but comparative studies of Cy/TBI regimens versus other TBI regimens are scarce. Furthermore, the recent expansion of post-transplant cyclophosphamide as graft-versus-host disease (GVHD) prophylaxis has increased its utility for cyclophosphamide-free conditioning regimens. Our institution has extensive experience with cord blood transplantation for relatively elderly patients with high-risk leukemia and has worked to develop safer and more effective MAC regimens other than Cy/TBI. The purpose of this study is to examine the safety and efficacy of fludarabine and melphalan combined with total-body irradiation (Flu/Mel/TBI) regimen, which is widely used at our institution, compared to Cy/TBI. Methods: We retrospectively analyzed adult acute leukemia patients who underwent allo-HCT between August 1994 to February 2023 at Toranomon Hospital. The inclusion criteria were as follows: a diagnosis of acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL), the first allo-HCT, and Cy (120mg/kg) /TBI (8-12Gy) or Flu (180mg/m 2) /Mel (80-120mg/m 2) /TBI (8-12Gy) as MAC regimen. We excluded patients who underwent haploidentical transplantation with post-transplant cyclophosphamide. The primary endpoint was the 5-year cumulative incidence of relapse, and the secondary endpoints were the 5-year cumulative incidence of non-relapse mortality (NRM), 5-year overall survival (OS), and relapse-free survival (RFS). OS and RFS were estimated by the Kaplan-Meier method and multivariate Cox proportional hazard models. The cumulative incidence of relapse and NRM were investigated with a competing risk analysis using Gray's test and multivariable Fine and Gray competing risk regression. Results: A total of 198 patients were included in this study, comprising 101 patients treated with Cy/TBI and 97 treated with Flu/Mel/TBI. Patients who received Flu/Mel/TBI were of higher age (Median age: Cy/TBI 36 years vs. Flu/Mel/TBI 53 years, p&amp;lt;0.01), higher ECOG PS score (PS≥1: 51.5% vs. 66.0%, p=0.044), fewer AML (49.5% vs. 22.7%, p&amp;lt;0.01), and more frequent CBT (45.5% vs. 76.3%, p&amp;lt;0.01). Disease status at HCT (CR1: 53.5% vs. 43.3%, p=0.154) and HCT-CI scores (HCT-CI≥1: 35.6% vs. 44.3%, p=0.214) were not different between the two regimen groups. Regarding the primary endpoint, the 5-year cumulative incidence of relapse was significantly lower in Flu/Mel/TBI group (36.8% vs. 24.9%, p= 0.035). The cumulative incidence of NRM was not significantly different between the two groups (19.1% vs. 25.2%, p=0.345). In the multivariate analysis, conditioning with Flu/Mel/TBI was significantly associated only with a lower risk of relapse (HR: 2.817; 95%CI: 1.183-6.712; p=0.019). Regarding NRM, only disease status not in CR1 was associated with a higher risk (CR1 vs. non-CR1 HR: 2.21; 95%CI: 1.095-4.468; p=0.027). There was no significant difference in 5-year OS (Cy/TBI 48.1% vs. Flu/Mel/TBI 51.4%, p=0.604) and RFS (44.2% vs. 49.9%, p=0.24). Conclusion: Despite older age and worse PS in the Flu/Mel/TBI group, Flu/Mel/TBI had a significantly lower 5-year cumulative relapse rate than Cy/TBI, with no significant difference in NRM. Our results suggest that Flu/Mel/TBI is a reasonable alternative to CY/TBI and may be a superior TBI-containing MAC regimen.

Optimizing Outcomes with Myeloablative Conditioning in Older Patients: Efficacy and Safety of Precision Engineered Orca-T in Patients > 55 Years Old with Hematologic Malignancies

Background Allogeneic hematopoietic stem cell transplants (alloSCT) offer the only curative treatment for many hematological cancers but carry the risk of significant toxicity including graft versus host disease (GvHD). Additionally, while the use of a myeloablative conditioning (MAC) regimen optimizes disease control, it can increase the complications associated with transplant and non-relapse mortality. Therefore, older patients are often deemed unfit for MAC and relegated to treatment with reduced intensity conditioning (RIC) regimens, which result in a higher incidence of relapse. Orca-T is a high-precision cell therapy biologic that includes stem and immune cells, derived from allogeneic donors, that leverages highly purified, polyclonal donor regulatory T cells to control alloreactive immune responses. The specific subsets selected in the Orca-T manufacturing process retain cells with therapeutic benefit while removing those that pose potential risks, allowing for intensification of concomitant chemotherapy and resulting in overall positive outcomes to date in the phase 1b trial (NCT04013685). To assess the safety and efficacy in an older patient population, we compared outcomes in those at least 55 years old to younger patients treated with Orca-T, receiving chemotherapy-based MAC with tacrolimus as single-agent GvHD prophylaxis. Methods As of 6/02/23, 38 patients ≥18 to &amp;lt;55 (younger) and 25 patients ≥55 years of age (older) received Orca-T as part of a multicenter Phase 1b single-arm trial and had the following diagnosis: acute myeloid, lymphoid or mixed phenotype leukemia in CR/CRi, myelodysplastic syndrome or chronic myeloid leukemia that was in chronic phase. Patients with active disease at the time of transplantation and patients with myelofibrosis were not included in this analysis. Patients received a myeloablative regimen consisting of intravenous busulfan, fludarabine, and thiotepa (BFT) prior to Orca-T, followed by single-agent GvHD prophylaxis with tacrolimus, and had an 8/8 related or unrelated matched donor. Donors were matched via DNA-based high-resolution typing of HLA-A, -B, -C, and -DRB1. Results Orca-T was successfully manufactured at a centralized GMP facility, distributed and infused at study sites throughout the U.S. Vein-to-vein time (i.e. time between end of donor apheresis to start of recipient's Orca-T infusion) was &amp;lt; 72 hours for all patients, majority &amp;lt; 60 hours. Median age was 47 in the younger group and 59 in the older group. The younger group was 50% female, and the older group was 36% female. The percentage that were of Hispanic or Latino ethnicity were 11% in the younger group, and 12% in the older group. 8%, 74% and 11% vs 12%, 44% and 32% had ALL, AML and MDS in the younger and older groups, respectively. A greater proportion of patients in the younger group had a baseline HCT-CI score of 0 (53%), while more had a baseline HCT-CI score of 4 (12%) in the older group. The median duration of follow-up for both groups was 12 months (Table). Disease free survival at 1 year was similar in both groups at 89% in the younger patients and 86% in the older patients (Figure). Modified GRFS* rate at 12 months among patients in the younger group was 86% compared to 77% in the older group. Non-relapse mortality at 1 year was 0% in both of these groups who received BFT MAC. Overall survival was high at 100% and 96% at 12 months in the younger and older patients, respectively. There were two patients &amp;gt; 65 when they received Orca-T; both remain alive without evidence of grade 3-4 acute GvHD, moderate to severe cGvHD, or relapse to date. Only 2 patients experienced grade 3 mucositis (no grade 4-5) and 1 younger patient (2.6%) and 1 older patient (4.0%) required total parenteral nutrition. Conclusions Our analysis suggests that Orca-T cell therapy represents a reduced toxicity alternative to conventional transplant and is well-tolerated by patients 55 and older, with comparable clinical outcomes to those 18 - &amp;lt; 55. In both patient groups, relapse incidence was low, with high GRFS. Remarkably, non-relapse mortality was zero at 1 year with excellent overall survival , suggesting that this regimen could potentially improve outcomes for older patients. An ongoing Phase 3 trial evaluating Orca-T vs. standard of care is currently enrolling throughout the United States.

High Disease-Free Survival in Patients with High-Risk MDS Treated with Orca-T

BACKGROUND Allogeneic hematopoietic cell transplant (alloHCT) may be a curative treatment option for patients with myelodysplastic syndrome (MDS). The use of investigational therapies that potentially reduce transplant toxicity could improve outcomes in this patient population with difficult to treat disease. Per CIBMTR, survival after alloHCT for MDS using matched donors is approximately 65% at 1 year and relapse-free survival at 1 year was ~69% in MDS patients in the RICMAC trial who received myeloablative conditioning (MAC). Orca-T is a high-precision cell therapy biologic that includes stem and immune cells, derived from allogeneic donors, that leverages highly purified, polyclonal donor regulatory T cells to control alloreactive immune responses. In this phase 1b study, Orca-T was evaluated in MDS patients who were eligible for transplant per 2017 International Expert Panel recommendations. METHODS As of 03/31/23, 16 patients with intermediate to very high risk (HR) MDS with ≤10% blasts in the bone marrow at the time of transplant had received Orca-T in the phase 1b study. IPSS-M prognostic scores were Low (6%), Moderate Low (6%), Moderate High (19%), High (44%), and Very High (25%). Baseline HCT-CI scores were 0 (n=6), 1 (n=3), 2 (n=2), 3 (n=3), and 4 (n=2). The median f/u was 19.1 months (range 6.3 - 32.2). Patients were aged 43 - 65 (median 59) and 56% female. Donors were 8/8 HLA-matched related (n=7) or unrelated (n=9). Patients received a busulfan-based myeloablative chemotherapy regimen prior to Orca-T, followed by single-agent GvHD prophylaxis with tacrolimus. RESULTS Orca-T was successfully manufactured in a single, centralized GMP manufacturing facility for all patients enrolled, distributed, and infused throughout the U.S. Orca-T was delivered within &amp;lt; 72 hours vein-to-vein (i.e. time between end of donor apheresis to start of recipient's Orca-T infusion). Disease-free survival (RFS) at 12 months was 94% (Figure). At 1 year, no patients had experienced grade ≥ 3 acute GvHD and moderate to severe chronic GvHD had occurred in 2 patients. Modified GRFS (survival free of Grade 3-4 aGvHD, moderate-to-severe cGvHD and relapse) at 12 months was 75%. Non-relapse mortality (NRM) and overall survival (OS) were 0% and 94%, respectively, at 12 months. Additionally, one MDS patient with very poor prognosis, characterized by mutated TP53 and complex karyotype, remains in CR without active signs of acute or cGvHD at 500 days post-alloHCT. CONCLUSIONS Orca-T demonstrated promising results in this HR-MDS patient population, including high RFS, low incidence of GvHD, and very high OS at 1 year. A randomized controlled phase 3 multi-center trial comparing Orca-T to SOC in patients with MDS, AML, and ALL is currently enrolling across the US (NCT05316701).

Outcomes of CMML patients undergoing allo-HCT are significantly worse compared to MDS-a study of the CMWP of the EBMT.

Although CMML since long has been separated from MDS, many studies continue to evaluate the outcomes of both diseases after hematopoietic cell transplantation (allo-HCT) together. Data evaluating outcomes of a large CMML cohort after allo-HCT compared to MDS are limited. We aim to compare outcomes of CMML to MDS patients who underwent allo-HCT between 2010 and 2018. Patients ≥18 years with CMML and MDS undergoing allo-HCT reported to the EBMT registry were analyzed. Progression to AML before allo-HCT was an exclusion criterion. Overall survival (OS), progression/relapse-free survival (PFS), relapse incidence (including progression) (REL), and non-relapse mortality (NRM) were evaluated in univariable and multivariable (MVA) Cox proportional hazard models including interaction terms between disease and confounders. In total, 10832 patients who underwent allo-HCT were included in the study, there were a total of 1466 CMML, and 9366 MDS. The median age at time of allo-HCT in CMML (median 60.5, IQR 54.3-65.2 years) was significantly higher than in the MDS cohort (median 58.8, IQR 50.2-64.5 years; p < .001). A significantly higher percentage of CMML patients were male (69.4%) compared to MDS (61.2%; p < .001). There were no clinically meaningful differences in the distribution of Karnofsky score, Sorror HCT-CI score at allo-HCT, and donor type, between the CMML and MDS patients. RIC platforms were utilized in 63.9% of CMML allo-HCT, and in 61.4% of MDS patients (p = .08). In univariable analyses, we found that OS, PFS, and REL were significantly worse in CMML when compared with MDS (all p < .0001), whereas no significant difference was observed in NRM (p = .77). In multivariable analyses, the HR comparing MDS versus CMML for OS was 0.81 (95% CI, 0.74-0.88, p < .001), PFS 0.76 (95% CI 0.70-0.82, p < .001), relapse 0.66 (95% CI 0.59-0.74, p < .001), and NRM 0.87 (95% CI 0.78-0.98, p = .02), respectively. The association between baseline variables and outcome was found to be similar in MDS and CMML (all interaction p > .05) except for a decreasing trend over time of the risk of relapse in CMML (HR allo-HCT per year later 0.94, 95% CI 0.90-0.98), whereas no such trend was observed in MDS (HR 1.00, 95% CI 0.98-1.02). The poor outcome observed for CMML could be related to variables not measured in this study or to factors inherent to the disease itself. This study demonstrates that outcomes of CMML patients after allo-HCT are significantly worse compared to MDS. The results of this study may contribute to future recommendations for allo-HCT in CMML patients.

Adjusting diffusing capacity for anemia in patients undergoing allogeneic HCT: a comparison of two methodologies

BackgroundDiffusing capacity (DLCO) measurements are affected by hemoglobin. Two adjustment equations are used: Cotes (recommended by ATS/ERS) and Dinakara (used in the hematopoietic stem cell transplantation comorbidity index [HCT-CI]). It is unknown how these methods compare, and which is better from a prognostication standpoint. Study designThis is a retrospective cohort of 1273 adult patients who underwent allogeneic HCT, completed a pre-transplant DLCO and had a concurrent hemoglobin measurement. Non-relapse mortality was measured using competing risk analysis. ResultsPatients had normal spirometry (FEV1 99.7% [IQR: 89.4–109.8%; FVC 100.1% [IQR: 91.0-109.6%] predicted), left ventricular ejection fraction (57.2[6.7]%) and right ventricular systolic pressure (30.1[7.0] mmHg). Cotes-DLCO was 85.6% (IQR: 76.5-95.7%) and Dinakara-DLCO was 103.6% (IQR: 90.7-117.2%) predicted. For anemic patients (Hb<10g/dL), Cotes-DLCO was 84.2% (IQR: 73.9–94.1%) while Dinakara-DLCO 111.0% (97.3–124.7%) predicted. Cotes-DLCO increased HCT-CI score for 323 (25.4%) and decreased for 4 (0.3%) patients. Cotes-DLCO was superior for predicting non-relapse mortality: for both mild (66-80% predicted, HR 1.55 [95%CI: 1.26-1.92, p < 0.001]) and moderate (<65% predicted, HR 2.11 [95%CI: 1.55-2.87, p<0.001]) impairment. In contrast, for Dinakara-DLCO, only mild impairment (HR 1.69 [95%CI 1.26-2.27, p < 0.001]) was associated with lower survival while moderate impairment was not (HR 1.44 [95%CI: 0.64-3.21, p = 0.4]). In multivariable analyses, after adjusting for demographics, hematologic variables, cardiac function and FEV1, Cotes-DLCO was predictive of overall survival at 1-year (OR 0.98 [95%CI: 0.97-1.00], p = 0.01), but Dinakara-DLCO was not (OR 1.00 [95%CI: 0.98-1.00], p = 0.20). ConclusionThe ERS/ATS recommended Cotes method likely underestimates DLCO in patients with anemia, whereas the Dinakara (used in the HCT-CI score) overestimates DLCO. The Cotes method is superior to the Dinakara method score in predicting overall survival and relapse-free survival in patients undergoing allogeneic HCT.

Comparable Survival for Fludarabine and Treosulfan Vs. Fludarabine and TBI As Conditioning Regimens in Patients with AML and MDS Undergoing Allogeneic Stem Cell Transplantation

Introduction Allogeneic stem cell transplantation (alloSCT) is a standard treatment option for patients (pts) with acute myeloid leukemia (AML) and myelodysplastic neoplasia (MDS) with relapse remaining the main cause of treatment failure. For AML pts transplanted in complete remission (CR) or MDS pts, the combination of fludarabin with fractionated total body irradiation (8 GyTBI, “FluTBI”) is an established conditioning regimen. Based on the favorable outcome data reported for fludarabine/treosulfan (“FluTreo”), especially for older and/or comorbid pts, this regimen has become a reliable dose reduced conditioning therapy prior to alloSCT and a valuable alternative to other TBI or chemotherapy-based regimens. Methods We conducted a retrospective analysis of 215 pts with AML in CR and 96 pts with MDS who underwent first alloSCT between 2010 and 2022 with a median follow-up (FU) of survivors of 34 months (range: 1 - 124 months). After conditioning therapy with FluTreo (150mg/m 2 fludarabin, 30g/m 2 treosulfan) or FluTBI (120mg/m 2 fludarabin, 4x2Gy TBI) pts were allografted from matched related (MRD; n=65), 10/10 human leukocyte antigen (HLA)-matched unrelated (MUD; n=200), or 9/10 HLA-matched unrelated donors (MMUD; n=46). For AML pts, any detectable molecular/cytogenetic alteration prior to alloSCT was classified as potentially measurable residual disease. Propensity score matching allowed us to identify 55 pair-matched FluTBI and FluTreo pts (nearest matching for age at alloSCT, sex, disease, HCT-CI score, ECOG, with a caliper distance of 0.5). Results Before matching, pts characteristics differed significantly between FluTreo and FluTBI in terms of age at alloSCT (median 64 vs. 47 yr), underlying disease (AML: 59% vs. 88%), ECOG (≥2 15% vs. 6%) and HCT-CI-Score (≥3 50% vs. 25%). In the AML subgroup, pts with measurable residual disease prior to alloSCT were significantly more frequent in the FluTreo group (68% vs. 48%, p&amp;lt;.001). GvHD prophylaxis consisted of calcineurin inhibitor and methotrexate/MMF in all pts. In addition, pts transplanted from unrelated donors received ATLG (Neovii). In the FluTreo group, more patients were transplanted from MRDs (24% vs. 14%, p.013). After matching, patient characteristics were well balanced with respect to age (median 57 vs. 55 yr, p.11), disease (AML/MDS) ( p .8), HCT-CI score ( p .24), sex ( p .85), donor types (MRD: 25.5% vs. 14.5%, MUD: 58.2% vs. 67.3%, MMUD: 16.4% vs. 18.2%, p .36) and measurable residual disease prior to alloSCT ( p .58). Risk groups for AML and MDS pts at diagnosis were comparable across both groups (ELN for AML and IPSS-R for MDS). Relapse incidences (RI) at 3 yrs were similar for FluTreo and FluTBI pts in the unmatched (25% vs. 25%, p.8) and matched cohorts (28% vs. 28% p .7). The non-relapse mortality (NRM) rate was &amp;lt;10% trending towards a lower NRM rate for the FluTBI group in the unmatched cohorts (at 1 yr: 8% vs. 5%, p .07) and a significant difference after matching (at 1 year 2% vs. 9% p .03). Overall survival (OS) for the whole cohort showed a trend towards an inferior outcome for FluTreo (3 yr: 71% vs. 79% p .06), after matching, no difference could be observed (3 yr: 80% vs. 71% p .54). Leukemia-free survival (LFS) was comparable across conditionings in the unmatched (59% vs. 66% p .42) and the matched cohorts (70% vs. 59% p .42). Irrespective of conditioning therapy, pts with measurable residual disease prior to alloSCT had comparable OS and LFS. However, for the matched cohort, pts with measurable disease treated with FluTreo showed a trend towards an inferior OS and LFS after 3 yr in contrast to FluTBI pts (OS: 66% vs. 80%, p .13; PFS: 58% vs. 67%, p .3). No significant differences could be observed in the incidence of acute onset graft versus host disease (GvHD) grade 2-4 at day 100 after alloSCT. Similarly, occurrence of chronic GvHD at 3 yr did not differ in the matched cohorts (32% vs. 43%, p .4). Conclusion With a meaningful median follow up of 34 months, our data for dose-reduced conditioning with either FluTreo or FluTBI highlight favorable and comparable survival rates of &amp;gt;70%. RI and NRM were low for both regimens. For pts with AML, who received FluTBI, measurable residual disease prior to alloSCT seemed to have no effect on outcome, while for the FluTreo cohort measurable residual disease prior to alloSCT showed a trend towards lower survival rates. This finding should be evaluated in a prospective trial comparing TBI and treosulfan based conditioning.

Blast Clearance after High Dose-Melphalan Conditioning for Allogeneic Stem Cell Transplantation in Relapsed and Refractory Acute Myeloid Leukemia

Introduction: For patients (pts) with relapsed or refractory acute myeloid leukemia (r/r AML) allogeneic stem cell transplantation (ASCT) has become an established highly effective and potential curative treatment option. Even for pts with active disease, direct ASCT using sequential conditioning regimens has shown promising outcomes. In this retrospective study, we examined prognostic factors for long-term survival in r/r AML pts with active disease with special focus to the prognostic value of blast clearance during condition therapy. Patients and Methods: 186 r/r AML pts treated with sequential conditioning regimens at our center between 2014-2023 were included in our analysis. Patients underwent high-dose melphalan (100 - 140 mg/m 2, day -11 prior ASCT) followed by either fractionated total body irradiation with 8 Gy (TBI, n = 71) or non-TBI regimens (busulfan, n = 101, or treosulfan, n = 14) in combination with fludarabin (120 - 150 mg/m 2) from day -6 before ASCT. TBI-based conditioning was applied almost exclusively in patients aged &amp;lt; 60 years. Graft versus host-disease (GvHD) prophylaxis consisted of calcineurin inhibitors, mycophenolate and anti-T-lymphocyte globulin. In 180 out of 186 patients, blast clearance was assessed by cytologic and flow cytometric blast count via bone marrow (BM) aspirate in median 5 days after Melphalan and prior to continuation of the sequential conditioning therapy. Blast clearance was defined as cytologic BM blast count &amp;lt; 5% and &amp;lt; 0.1% BM cells with leukemia-associated immunophenotype in flow cytometry. Results: Median pts age was 67 years (range 45 - 76 years) in the non-TBI group and 51 years (range 19 - 71 years) in the TBI group, respectively. Median follow up of surviving patients was 46 months. As expected, comorbidities and disease-specific factors varied between these groups. HCTCI scores &amp;gt; 3 points were observed in 14% of TBI pts compared to 32% in non-TBI pts ( p .01) and 45% versus 54% harbored adverse risk genetics according to European Leukemia Net (ELN) 2017 classification ( p .41), respectively. In the non-TBI group, 38% of the pts had a secondary or therapy-related AML compared to 20% of pts in the TBI group ( p .03). HLA-mismatched (&amp;lt;10/10 matched) donor grafts were transplanted in 21% (TBI) vs. 20% (non-TBI) of the pts. 185 of 188 pts received GCS-F mobilized stem cell grafts; 3 pts received a bone marrow graft. Kaplan-Meier estimates for overall survival (OS) with and without blast clearance at 2 years were 69.6% (95% CI 60.1-80.6%) vs. 58% (95% CI 48.8-69.1%, p .33), for event free survival (EFS, event defined as death or overt relapse) 58.9% (95% CI 49-70.8%) vs. 46.1% (95% CI 36.7-58.1%, p .2), respectively. We included the re-occurrence / persistence of defined molecular and cytogenetic markers or decreasing CD34 + bone marrow chimerism (&amp;lt; 95%) after transplant as measures for impending relapse as a modified EFS. The EFS including impending relapse was 49.8% (95% CI 40-62%) vs. 36.4% (27.7-47.8%) after 2 years. A non-significant trend with reduced relapse risk for those patients who achieved blast clearance after Melphalan ( p .1, HR 0.73) was observed. Most patients with impending relapse showed similar survival as patients without evidence of relapse after ASCT. In multivariate cox regression, age, HCTCI scores &amp;gt; 3 points, adverse risk according to ELN 2017 definitions and donor mismatch &amp;lt; 10/10 resulted in adverse prognosis. Especially, patients with mismatched donors displayed highly significant inferior outcomes. Both leukemic burden prior to ASCT as well as blast clearance after melphalan showed no significant correlation with clinical outcome parameters. Conclusion: Sequential conditioning regimens followed by ASCT offer long-term survival for more than 50% of pts with active relapsed or refractory AML. Patients who did not achieve complete blast clearance during conditioning therapy showed a trend towards higher relapse risk after ASCT which did not result in inferior survival. This underscores the importance of close monitoring and early interventions such as accelerated immunosuppression tapering, preemptive donor lymphocyte infusions and targeted therapies in case of impending relapse after ASCT.

Allogeneic Hematopoietic Cell Transplantation for Vexas Syndrome: Results of a Multicenter Study from the Chronic Malignancies and Autoimmune Disease Working Parties of the EBMT

VEXAS is a new entity encompassing a variety of clinical manifestations spanning from autoimmune/auto-inflammatory to hematologic conditions including MDS, plasma cell dyscrasias, and recurrent thrombosis. Somatic mutations of the X-linked UBA1 gene in hematopoietic stem and progenitor cells constitute the molecular underpinnings of VEXAS, typically occurring in men during the 6 th decade of life. Over the last 2 years since its first description, VEXAS has elicited wide medical interest resulting in the identification of pleomorphic clinical phenotypes, which make this syndrome a “big masquerader” and a clinical diagnostic challenge. Treatment strategies aim at suppression of the UBA1-mutant clone (e.g., with azacitidine or allo-HCT) or blockade of the downstream pleiotropic effects of hypercytokinemia. However, no treatment guidelines exist to date, and patients may manifest life-threatening inflammatory symptoms frequently refractory to many therapies. As few literature reports have described the successful use of transplant, we here report the outcomes of patients with VEXAS in a multicenter EBMT registry-based study. Leveraging a multidisciplinary liaison of EBMT and key rheumatology centers across Europe, we disseminated a survey to gather further information on patients with VEXAS undergoing allo-HCT to explore overall survival (OS), transplant-specific outcomes, and reversal of the VEXAS clinical phenotype. We evaluated a total of 13 patients, all males and with a median age of 58 years (IQR, 52-63) at the time of transplant. The majority had concomitant MDS (n=10) while 2 presented with only autoinflammatory manifestations, and 1 had MPN. In line with the genomics of the disease, UBA1 mutations consisted of missense substitutions at the Met41 hotspot in 10 cases (n=6 Thr/3 Val/1 Leu), splice site (n=2 c.118-2A&amp;gt;C, c.118-1G&amp;gt;C), and the rare p.Ser56Phe at a median VAF of 73% (IQR, 45-84). All patients presented with anemia and had concomitant rheumatologic manifestations ( Fig1A) requiring specific treatment. VEXAS symptoms preceded the diagnosis of MDS/MPN in all but one case. Cytogenetics was normal in all VEXAS/MDS cases, which also displayed lower-risk IPSS-R scores with a median bone marrow blast of 2% (IQR, 1-4). Allo-HCT was performed at a median of 46 months (IQR, 22-59) from VEXAS onset. Before transplant, patients received a variety of both rheumatological (steroids/anti-interleukins) and hematological (azacitidine/ruxolitinib) treatments, with a high refractoriness (median number of lines 5, range 1-13). In all cases, stability of the clinical phenotype with no flares/uncontrolled manifestations was achieved at the time of the procedure. Conversely, in 3 MDS cases, clonal progression with acquisition of additional chromosomal alterations [+8, +21, t(12;16)] was evident. Overall, 62% of patients had a Karnofsky score &amp;gt;80% and low/intermediate (&amp;lt; 3) HCT-CI scores. Donor choice consisted of matched related in 23%, matched unrelated in 54%, mismatched related in 15%, and mismatched unrelated in 8% of the cohort. Peripheral blood was the preferred stem cell source in all but one case and conditioning regimen consisted of a variety of fludarabine-based strategies (n=4 MAC, n=9 RIC). GvHD prophylaxis was based on post-transplant cyclophosphamide (n=4), or serotherapy (n=8 ATG, n=1 alemtuzumab), in combination with cyclosporine and short-course methotrexate (n=5) or mycophenolate (n=4). All patients engrafted at a median time of 16 and 14 days for neutrophils and platelets, respectively. Overall, 92% of patients achieved full donor chimerism at last-follow-up. Grade II-IV acute GvHD occurred in 23% of cases, whereas only 1 patient presented with chronic extensive GvHD, which resolved 1-year after transplant. With a median time of 19 months (IQR, 8-42) from allo-HCT, 2-year OS was 82% ( Fig1B). Of note, 1 patient died because of infection and 1 because of CNS toxicity, whereas all cases with prolonged follow-up (&amp;gt;10 months) displayed resolution of the VEXAS clinical phenotypes and were able to discontinue immunosuppression between 2-8 months post-transplant. Allo-HCT remains the only curative option for MDS and is used to treat rheumatologic conditions refractory to conventional treatments. We present the largest series of allografted VEXAS cases. Given the hemato-inflammatory nature of the disease, allo-HCT may be a viable option in selected patients.