Defining the intensity of conditioning regimens: working definitions

Current status of conditioning regimens in haploidentical hematopoietic cell transplantation

The development of effective prophylaxis strategies against graft-versus-host disease (GVHD) has contributed to the widespread use of haploidentical related hematopoietic cell transplantation (Haplo-HCT). Currently, GVHD prophylaxis containing posttransplant cyclophosphamide (PTCY) is considered the standard of care in Haplo-HCT, and recent studies have shown comparable results for PTCY-based Haplo-HCT and HCT from other donor sources. The conditioning regimen plays an important role in eradicating tumor cells to prevent disease relapse and suppressing the recipient's immune system to facilitate engraftment. PTCY-based Haplo-HCT was initially developed using a nonmyeloablative conditioning regimen consisting of fludarabine, cyclophosphamide and low-dose total body irradiation, but high relapse rates reinforced the need to intensify the conditioning regimen. In this respect, various myeloablative and reduced-intensity conditioning regimens have been investigated. However, the optimal conditioning regimens for PTCY-based Haplo-HCT have not yet been established, and this issue needs to be addressed based on data from patients undergoing the procedure. In this article, we review the existing literature on conditioning regimens for PTCY-based Haplo-HCT and discuss future perspectives.

Varicella-Zoster Virus Reactivation After Pediatric Allogeneic Hematopoietic Stem Cell Transplantation, Single-Center Experience of Acyclovir Prophylaxis

BACKGROUND

Varicella-zoster virus (VZV) reactivation is the most common infectious complication in the late posthematopoietic stem cell transplantation (HSCT) period and is reported as 16%-41%. Acyclovir prophylaxis is recommended for at least 1 year after HSCT to prevent VZV infections. However, studies on the most appropriate prophylaxis are ongoing in pediatric patients.

METHODS

Patients who underwent allogeneic HSCT between January 1, 1996 and January 1, 2020 were retrospectively analyzed to outline the characteristics of VZV reactivation after allogeneic HSCT in pediatric patients using 6 months acyclovir prophylaxis.

RESULTS

There were 260 patients and 273 HSCTs. Median age was 10.43 (0.47-18.38), and 56% was male. Median follow-up was 2325 days (18-7579 days). VZV reactivation occurred in 21.2% (n = 58) at a median of 354 (55-3433) days post-HSCT. The peak incidence was 6-12 months post-HSCT (43.1%). Older age at HSCT, female gender, history of varicella infection, lack of varicella vaccination, low lymphocyte, CD4 count, and CD4/CD8 ratio at 9 and 12 months post-HSCT was found as a significant risk for herpes zoster (HZ) in univariate analysis, whereas history of varicella infection and low CD4/CD8 ratio at 12 months post-HSCT was an independent risk factor in multivariate analysis.

CONCLUSIONS

Tailoring acyclovir prophylaxis according to pre-HCT varicella history, posttransplant CD4 T lymphocyte counts and functions, and ongoing immunosuppression may help to reduce HZ-related morbidity and mortality.

Transplant versus no transplant in myelodysplastic syndrome and acute myeloid leukemia with TP53 mutation; a referral center experience

A remarkably high rate of post-transplant relapse in patients with TP53-mutated myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) calls to question the utility of allogeneic stem cell transplant (HSCT). We, therefore, performed a retrospective analysis to compare the outcomes between HSCT (N = 38) versus non-HSCT (N = 45) approaches. Patients in the HSCT cohort were younger (median age 63 vs. 72) while patients in the non-HSCT cohort more commonly had complex karyotype with chromosome 17 aberrancy and 5q deletion (p < .01). A total of 69 TP53 variants including 64 pathogenic variants, and 5 variants of undetermined significance were detected. Nine patients (4 in HSCT and 5 in non-HSCT) had multi-hit TP53 variants. After induction: 57.9% versus 56.6% in the HSCT versus non-HSCT cohort achieved morphologic complete remission. Median time to HSCT was 6 months and median follow-up was 15.1 months for HSCT and 5.7 months for non-HSCT. Median disease-free survival (DFS) and overall survival (OS) were 11.7 and 15.9 months for HSCT, and 4.1 and 5.7 months for non-HSCT cohorts, respectively. Non-relapse mortality at 12 months was 22% versus 44% for HSCT versus non-HSCT. In the HSCT cohort, the rate of grade II-IV acute and chronic graft-versus-host disease (GVHD) was 55% and 18%, respectively. None of the patients from the non-HSCT cohort were alive while four patients from the HSCT cohort were alive, in remission, and without GVHD (GRFS) at the time of abstraction. Better treatment strategies for patients with TP53-mutated MDS/AML remain an area of unmet clinical need.

Lower relapse incidence with haploidentical versus matched sibling or unrelated donor hematopoietic cell transplantation for core-binding factor AML patients in CR2: A study from the Global Committee and the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) is recommended for core-binding factor mutated (CBF) AML patients achieving second complete remission (CR2). However, approximately 20% of patients may relapse after transplant and donor preference remains unclear. We compared in this EBMT global multicenter registry-based analysis the allo-HCT outcomes using either haploidentical (Haplo), matched siblings donors (MSD), or 10/10 matched unrelated donors (MUD). Data from 865 de novo adult CBF AML patients in CR2 receiving allo-HCT in 227 EBMT centers from 2010 to 2022 were analyzed, in which 329 MSD, 374 MUD, and 162 Haplo-HCTs were included. For the entire cohort, 503 (58%) patients were inv(16)/CBFB-MYH11 and 362 patients (42%) were t(8;21)/RUNX1-RUNX1T1 AML. On multivariate analysis, Haplo-HCT was associated with a lower Relapse Incidence (RI) compared to either MSD (hazard ratio [HR] = 0.56, 95% CI 0.32-0.97; p < .05) or MUD (HR = 0.57, 95% CI: 0.33-0.99, p < .05). No significant difference was observed among the 3 types of donors on LFS, OS and GRFS. CBF-AML with t(8;21) was associated with both higher RI (HR = 1.79, 95% CI 1.3-2.47; p < .01) and higher NRM (HR = 1.58, 95% CI 1.1-2.27; p < .01) than CBF-AML with inv(16), which led to worse LFS, OS and GRFS. To conclude, for CBF-AML patients in CR2, Haplo-HCTs were associated with a lower RI compared to MSD and MUD allo-HCTs. There was no difference on LFS, OS or GRFS. CBF AML patients with inv(16) had a better progonosis than those with t(8;21) after allo-HCT in CR2.

Role of gene therapy in sickle cell disease

BACKGROUND

Gene therapy is an emerging treatment for sickle cell disease that works by replacing a defective gene with a healthy gene, allowing the body to produce normal red blood cells. This form of treatment has shown promising results in clinical trials, and is a promising alternative to traditional treatments. Gene therapy involves introducing a healthy gene into the body to replace a defective gene. The new gene can be delivered using a viral vector, which is a modified virus that carries the gene. The vector, carrying the healthy gene, is injected into the bloodstream. The healthy gene then enters the patient's cells and begins to produce normal hemoglobin, the protein in red blood cells that carries oxygen throughout the body.

METHODOLOGY

We conducted an all-language literature search on Medline, Cochrane, Embase, and Google Scholar until December 2022. The following search strings and Medical Subject Heading (MeSH) terms were used: "Sickle Cell," "Gene Therapy" and "Stem Cell Transplantation". We explored the literature on Sickle Cell Disease for its epidemiology, etiopathogenesis, the role of various treatment modalities and the risk-benefit ratio of gene therapy over conventional stem cell transplant.

RESULTS

Gene therapy can reduce or eliminate painful episodes, prevent organ damage, and raise the quality of life for those living with the disease. Additionally, gene therapy may reduce the need for blood transfusions and other traditional treatments. Gene therapy has the potential to improve the lives of those living with sickle cell disease, as well as reduce the burden of the disease on society.

Acute kidney injury and risk factors in pediatric patients undergoing hematopoietic stem cell transplantation

BACKGROUND

Acute kidney injury (AKI) is a common complication of hematopoietic stem cell transplantation (HSCT) with increased mortality and morbidity. Understanding the risk factors for AKI is essential. This study aimed to identify AKI incidence, risk factors, and prognosis in pediatric patients post-HSCT.

METHODS

We conducted a retrospective case-control study of 278 patients who were divided into two groups: those with AKI and those without AKI (non-AKI). The groups were compared based on the characteristics and clinical symptoms of patients, as well as post-HSCT complications and the use of nephrotoxic drugs. Logistic regression analysis was employed to identify the risk factors for AKI.

RESULTS

A total of 16.9% of patients had AKI, with 8.5% requiring kidney replacement therapy. Older age (OR 1.129, 95% CI 1.061-1.200, p < 0.001), sinusoidal obstruction syndrome (OR 2.562, 95% CI 1.216-5.398, p = 0.011), hemorrhagic cystitis (OR 2.703, 95% CI 1.178-6.199, p = 0.016), and nephrotoxic drugs, including calcineurin inhibitors, amikacin, and vancomycin (OR 17.250, 95% CI 2.329-127.742, p < 0.001), were identified as significant independent risk factors for AKI following HSCT. Mortality rate and mortality due to AKI were higher in stage 3 patients than those in stage 1 and 2 AKI (p = 0.019, p = 0.007, respectively). Chronic kidney disease developed in 1 patient (0.4%), who was in stage 1 AKI (2.1%).

CONCLUSIONS

AKI poses a serious threat to children post-HSCT, leading to alarming rates of mortality and morbidity. To enhance outcomes and mitigate these risks, it is vital to identify AKI risk factors, adopt early preventive strategies, and closely monitor this patient group.

Longitudinal outcome over four decades of allogeneic stem cell transplantation: a single center experience

This 45-year study (1978-2022) at a single institution evaluated HSCT outcomes and complications, emphasizing recent advances, with to provide insights into HSCT's evolving field and ongoing efforts to enhance patient outcomes. Involving 1707 patients, the study revealed an initial phase (1978-1987) with a limited activity that yielded modest outcomes, a nearly three-decade span (1988-2016) with a substantial increase in transplant activity, emphasizing umbilical cord blood transplantation (UCBT) for patients lacking a suitable matched sibling donor. In addition to a gradual increase in recipient age, significant improvement in outcomes emerged in the recent period (2017-2022), marked by UCBT replacement with haploidentical transplants, introduction of PTCY-based GVHD prophylaxis for all type of transplants, and increased use of conditioning regimens with thiotepa, busulfan, and fludarabine. In this period, reductions in GVHD, non-relapse mortality, and relapse rates significantly contributed to improved overall survival, event-free survival, and GVHD-free/relapse-free survival. The study identified specific factors, including GVHD prophylaxis and donor selection changes, associated with these positive trends. This four-decade study provides a unique perspective on allogeneic HSCT, showcasing the dynamic evolution of transplantation practices and their impact on outcomes, offering valuable insights for personalized treatment approaches and emphasizing continual innovation in this critical therapeutic modality.

Optimizing Outcomes in Mismatched Unrelated Donor Allogeneic Transplantation: Post-Transplant Cyclophosphamide's Dual Impact on Graft versus Host Disease Incidence and Overall Survival: Retrospective Analysis on Behalf of Polish Adult Leukemia Group

Allogeneic hematopoietic cell transplantation (allo-HSCT) stands as an effective treatment method for various hematologic malignancies. However, graft-versus-host disease (GvHD), an intricate immunological phenomenon where donor immune cells target recipient tissues, remains a significant challenge, particularly in mismatched unrelated donors (MMUD). Post-transplant cyclophosphamide (PTCy) has emerged as a promising immunosuppressive strategy, revolutionizing haploidentical transplantation and demonstrating promise in MMUD settings. Background/Objectives: This study aimed to evaluate the impact of PTCy on MMUD allo-HSCT outcomes, specifically its effects on GvHD incidence and overall survival, compared to anthitymocyte globulin (ATG). Methods: One hundred seventy-four patients were classified into three groups based on the type of transplantation: PTCy-haplo (114/174; 65.5%), PTCy-MMUD (23/174; 13.2%), and ATG-MMUD (37/174; 21.2%). Results: Our findings showed that PTCy-MMUD significantly reduced acute GvHD occurrence compared to PTCy-haplo and ATG-MMUD approaches (p = 0.006). The delayed onset of acute GvHD in the PTCy-MMUD group suggests a more controlled immune reconstitution, contributing to the lower incidence. Importantly, PTCy-MMUD exhibited enhanced five-year overall survival rates, aligning with the notion that reduced GvHD correlates with improved patient outcomes (p = 0.032). Conclusions: We believe that this study contributes valuable insights into PTCy-MMUD's management, underscoring its potential to significantly reduce GvHD incidence and enhance survival outcomes. Although further investigations and clinical trials are warranted, this research underscores the promising role of PTCy-based GvHD prophylaxis in improving MMUD allo-HCT success.

Impact of payment source, referral site, and place of residence on outcomes after allogeneic transplantation in Mexico

BACKGROUND

The impact of social determinants of health in allogeneic transplant recipients in low- and middle-income countries is poorly described. This observational study analyzes the impact of place of residence, referring institution, and transplant cost coverage (out-of-pocket vs government-funded vs private insurance) on outcomes after allogeneic hematopoietic stem cell transplantation (alloHSCT) in two of Mexico's largest public and private institutions.

AIM

To evaluate the impact of social determinants of health and their relationship with outcomes among allogeneic transplant recipients in Mexico.

METHODS

In this retrospective cohort study, we included adolescents and adults ≥ 16 years who received a matched sibling or haploidentical transplant from 2015-2022. Participants were selected without regard to their diagnosis and were sourced from both a private clinic and a public University Hospital in Mexico. Three payment groups were compared: Out-of-pocket (OOP), private insurance, and a federal Universal healthcare program “Seguro Popular”. Outcomes were compared between referred and institution-diagnosed patients, and between residents of Nuevo Leon and out-of-state. Primary outcomes included overall survival (OS), categorized by residence, referral, and payment source. Secondary outcomes encompassed early mortality, event-free-survival, graft-versus-host-relapse-free survival, and non-relapse-mortality (NRM). Statistical analyses employed appropriate tests, Kaplan-Meier method, and Cox proportional hazard regression modeling. Statistical software included SPSS and R with tidycmprsk library.

RESULTS

Our primary outcome was overall survival. We included 287 patients, n = 164 who lived out of state (57.1%), and n = 129 referred from another institution (44.9%). The most frequent payment source was OOP (n = 139, 48.4%), followed by private insurance (n = 75, 26.1%) and universal coverage (n = 73, 25.4%). No differences in OS, event-free-survival, NRM, or graft-versus-host-relapse-free survival were observed for patients diagnosed locally vs in another institution, nor patients who lived in-state vs out-of-state. Patients who covered transplant costs through private insurance had the best outcomes with improved OS (median not reached) and 2-year cumulative incidence of NRM of 14% than patients who covered costs OOP (Median OS and 2-year NRM of 32%) or through a universal healthcare program active during the study period (OS and 2-year NRM of 19%) (P = 0.024 and P = 0.002, respectively). In a multivariate analysis, payment source and disease risk index were the only factors associated with overall survival.

CONCLUSION

In this Latin-American multicenter study, the site of residence or referral for alloHSCT did not impact outcomes. However, access to healthcare coverage for alloHSCT was associated with improved OS and reduced NRM.

Younger unrelated donors may be preferable over HLA match in the PTCy era: a study from the ALWP of the EBMT

ABSTRACT

There is a paucity of information on how to select the most appropriate unrelated donor (UD) in hematopoietic stem cell transplantation (HSCT) using posttransplant cyclophosphamide (PTCy). We retrospectively analyzed the characteristics of 10/10 matched UDs (MUDs) and 9/10 mismatched UDs (MMUDs) that may affect transplant outcomes in patients with acute myeloid leukemia (AML) in first or second complete remission (CR1 or CR2). The primary end point was leukemia-free survival (LFS). Overall, 1011 patients were included with a median age of 54 years (range, 18-77). Donors had a median age of 29 years (range, 18-64); 304 (30%) were females, of which 150 (15% of the whole group) were donors to male recipients, and 621 (61%) were MUDs; 522 (52%) had negative cytomegalovirus (CMV-neg) serostatus, of which 189 (19%) were used for CMV-neg recipients. Donor age older than 30 years had a negative impact on relapse (hazard ratio [HR], 1.38; 95% confidence interval [CI], 1.06-1.8), LFS (HR, 1.4; 95% CI, 1.12-1.74), overall survival (HR 1.45; 95% CI, 1.14-1.85) and graft-versus-host disease (GVHD) free, relapse-free survival (HR, 1.29; 95% CI, 1.07-1.56). In addition, CMV-neg donors for CMV-neg recipients were associated with improved LFS (HR, 0.74; 95% CI, 0.55-0.99). The use of MMUD and female donors for male recipients did not significantly impact any transplant outcomes. For patients undergoing HSCT from a UD with PTCy for AML, donor age <30 years significantly improves survival. In this context, donor age might be prioritized over HLA match considerations. In addition, CMV-neg donors are preferable for CMV-neg recipients. However, further research is needed to validate and refine these recommendations.

Comparable relapse incidence after unrelated allogeneic stem cell transplantation with post-transplant cyclophosphamide versus conventional anti-graft versus host disease prophylaxis in patients with acute myeloid leukemia: A study on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

We compared relapse incidence (RI) post-unrelated transplantation with post-transplant cyclophosphamide (PTCy) versus no PTCy graft-versus-host disease (GVHD) prophylaxis, in 7049 acute myeloid leukemia (AML) patients in remission, 707 with PTCy, and 6342 without (No PTCy). The patients in the PTCy group were younger, 52.7 versus 56.6 years (p < .001). There were more 9/10 donors in the PTCy group, 33.8% versus 16.4% (p < .001), and more received myeloablative conditioning, 61.7% versus 50.2% (p < .001). In the No PTCy group, 87.7% of patients received in vivo T-cell depletion. Neutrophil and platelet engraftment were lower in the PTCy versus No PTCy group, 93.8% and 80.9% versus 97.6% and 92.6% (p < .001). RI was not significantly different in the PTCy versus the No PTCy group, hazard ratio (HR) of 1.11 (95% confidence interval [CI] 0.9-1.37) (p = .31). Acute GVHD grades II-IV and III-IV, were significantly lower in the PTCy versus the No PTCy group, HR of 0.74 (95% CI 0.59-0.92, p = .007) and HR = 0.56 (95% CI 0.38-0.83, p = .004), as were total and extensive chronic GVHD, HRs of 0.5 (95% CI 0.41-0.62, p < .001) and HR = 0.31 (95% CI 0.22-0.42, p < .001). Non-relapse mortality (NRM) was significantly lower with PTCy versus the No PTCy group, HR of 0.67 (95% CI 0.5-0.91, p = .007). GVHD-free, relapse-free survival (GRFS) was higher in the PTCy versus the No PTCy group, HR of 0.69 (95% CI 0.59-0.81, p = .001). Leukemia-free survival (LFS) and overall survival (OS) did not differ between the groups. In summary, we observed comparable RI, OS, and LFS, significantly lower incidences of GVHD and NRM, and significantly higher GRFS in AML patients undergoing unrelated donor-hematopoietic stem cell transplantation with PTCy versus No PTCy GVHD prophylaxis.

Early blast clearance during sequential conditioning prior to allogeneic stem cell transplantation in patients with acute myeloid leukaemia

For patients with relapsed or refractory AML, sequential conditioning prior to allogeneic stem cell transplantation (alloSCT) is an established and potentially curative treatment option. Early response to treatment during conditioning indicates chemotherapy-responsive disease and may have prognostic value. We retrospectively evaluated blast clearance on day 5 after melphalan, administered 11 days prior to alloSCT as part of a sequential conditioning in 176 patients with active AML. Overall survival (OS) was 52% (95% confidence interval [CI] 45%-60%), and relapse-free survival (RFS) was 47% (95% CI 40%-55%) at 3 years. Patients who achieved early blast clearance did not show a significant improvement in OS and RFS (OS, hazard ratio [HR] HR 0.75, p 0.19; RFS, HR 0.71, p 0.09, respectively), but had a significantly lower non-relapse mortality rate (HR 0.46, p 0.017). HLA-mismatched donor, older age, adverse genetic risk and higher comorbidity scores were associated with inferior survival outcomes. A high initial blast count was only associated with inferior prognosis in patients receiving chemotherapy-only compared to total body irradiation containing conditioning therapy. These results indicate that for patients transplanted with active AML, sensitivity to chemotherapy might be of less importance, compared to other disease- and transplant-related factors.

Impact of post-transplant cyclophosphamide and splenomegaly on primary graft failure and multi-lineage cytopenia after allogeneic hematopoietic cell transplantation

Primary graft failure (PGF) and multi-lineage cytopenia (MLC) increase the risk of nonrelapse mortality in allogeneic hematopoietic cell transplants (HCT). We evaluated the impact of post-transplant cyclophosphamide (PTCy) and splenomegaly on PGF and MLC for hematological malignancies. This study included patients with PTCy (N=84) and conventional graft-vs.-host disease prophylaxis (N=199). The occurrence of splenomegaly varied widely, ranging from 17.1 % (acute myeloid leukemia) to 66.7 % (myeloproliferative neoplasms). Ten patients (N=8 in the PTCy and N=2 in the non- PTCy) developed PGF, and 44 patients developed MLC (both N=22). PTCy and severe splenomegaly (≥20 cm) were risk factors for PGF (odds ratio (OR): 10.40, p<0.01 and 6.74, p=0.01 respectively). Moreover, severe splenomegaly was a risk factor for PGF in PTCy patients (OR: 10.20, p=0.01). PTCy (hazard ratio (HR) 2.09, p=0.02), moderate (≥15, <20 cm, HR 4.36, p<0.01), and severe splenomegaly (HR 3.04, p=0.01) were independent risk factors for MLC. However, in subgroup analysis in PTCy patients, only mild splenomegaly (≥12, <15 cm, HR 4.62, p=0.01) was a risk factor for MLC. We recommend all patients be screened for splenomegaly before HCT, and PTCy is cautioned in those with splenomegaly.

Idiopathic Pneumonitis Syndrome After Total Body Irradiation in Pediatric Patients Undergoing Myeloablative Hematopoietic Stem Cell Transplantation: A PENTEC Comprehensive Review

PURPOSE

Pulmonary complications, especially idiopathic pneumonitis syndrome (IPS), are potentially life altering or fatal sequelae of hematopoietic cell transplantation (HCT). Total body irradiation (TBI) as part of the conditioning regimen has been implicated in IPS. A comprehensive PENTEC (Pediatric Normal Tissues in the Clinic) review was performed to increase our understanding of the role of TBI in the development of acute, noninfectious IPS.

METHODS AND MATERIALS

A systematic literature search was conducted using the MEDLINE, PubMed, and Cochrane library databases for articles describing pulmonary toxicity in children treated with HCT. Data pertaining to TBI and pulmonary endpoints were extracted. Risk of IPS was analyzed in relation to patient age, TBI dose, fractionation, dose rate, lung shielding, timing, and type of transplant, with the goal to better understand factors associated with this complication in children undergoing HCT. A logistic regression model was developed using a subset of studies with comparable transplant regimens and sufficient TBI data.

RESULTS

Six studies met criteria for modeling of the correlation of TBI parameters with IPS; all consisted of pediatric patients undergoing allogeneic HCT with a cyclophosphamide-based chemotherapy regimen. IPS was variably defined, but all studies that reported IPS were included in this analysis. The mean incidence of post-HCT IPS was 16% (range, 4%-41%). Mortality from IPS, when it occurred, was high (median, 50%; range, 45%-100%). Fractionated TBI prescription doses encompassed a narrow range of 9 to 14 Gy. Many differing TBI methods were reported, and there was an absence of 3-dimensional dose analysis of lung blocking techniques. Thus, a univariate correlation between IPS and total TBI dose, dose fractionation, dose rate, or TBI technique could not be made. However, a model, built from these studies based on prescribed dose using a normalized dose parameter of equivalent dose in 2-Gy fractions (EQD2), adjusted for dose rate, suggested correlation with the development of IPS (P = .0004). The model-predicted odds ratio for IPS was 24.3 Gy-1 (95% confidence interval, 7.0-84.3). Use of TBI lung dose metrics (eg, midlung point dose) could not be successfully modeled, potentially because of dosimetric uncertainties in the actual delivered volumetric lung dose and imperfections in our modeling process.

CONCLUSIONS

This PENTEC report is a comprehensive review of IPS in pediatric patients receiving fractionated TBI regimens for allogenic HCT. IPS was not clearly associated with 1 single TBI factor. Modeling using dose-rate adjusted EQD2 showed a response with IPS for allogeneic HCT using a cyclophosphamide-based chemotherapy regimen. Therefore, this model suggests IPS mitigation strategies can focus on not just the dose and dose per fraction but also the dose rate used in TBI. More data are needed to confirm this model and to determine the influence of chemotherapy regimens and contribution from graft-versus-host disease. The presence of confounding variables (eg, systemic chemotherapies) that affect risk, the narrow range of fractionated TBI doses found in the literature, and limitations of other reported data (eg, lung point dose) may have prevented a more straightforward link between IPS and total dose from being observed.

Clostridium butyricum MIYAIRI 588 contributes to the maintenance of intestinal microbiota diversity early after haematopoietic cell transplantation

In patients undergoing haematopoietic stem-cell transplantation (HSCT), the intestinal microbiota plays an important role in prognosis, transplant outcome, and complications such as graft-versus-host disease (GVHD). Our prior research revealed that patients undergoing HSCT substantially differed from healthy controls. In this retrospective study, we showed that administering Clostridium butyricum MIYAIRI 588 (CBM588) as a live biotherapeutic agent is associated with maintaining intestinal microbiota in the early post-HSCT period. Alpha diversity, which reflects species richness, declined considerably in patients who did not receive CBM588, whereas it remained consistent in those who received CBM588. In addition, β-diversity analysis revealed that CBM588 did not alter the gut microbiota structure at 7-21 days post-HSCT. Patients who developed GVHD showed structural changes in their microbiota from the pre-transplant period, which was noticeable on day 14 before developing GVHD. Enterococcus was significantly prevalent in patients with GVHD after HSCT, and the population of Bacteroides was maintained from the pre-HSCT period through to the post-HSCT period. Patients who received CBM588 exhibited a contrasting trend, with lower relative abundances of both genera Enterococcus and Bacteroides. These results suggest that preoperative treatment with CBM588 could potentially be beneficial in maintaining intestinal microbiota balance.

Outcomes from hematopoietic stem cell transplantation following treosulfan-based conditioning: A clinical and pharmacokinetic analysis

BACKGROUND

The aims of this study are to report our experience with treosulfan-based conditioning regimens for patients with non-malignant hematologic conditions, correlating clinical outcomes at different time points post-transplant with treosulfan exposure (AUC).

METHODS

This study was a single-center observational study investigating overall survival (OS), disease-free survival (DFS), and event-free survival (EFS) end-points post-transplant. The consequences of treosulfan AUC with respect to toxicity, correction of underlying disease, and long-term chimerism were also explored using pharmacokinetic analysis.

RESULTS

Forty-six patients received 49 transplants with treosulfan and fludarabine-based conditioning between 2005 and 2023. Twenty-four patients also received thiotepa. Donor chimerism was assessed on either whole blood or sorted cell lines at different time points post-transplant. Thirty-nine patients received treosulfan pharmacokinetic assessment to evaluate cumulative AUC, with five infants receiving real-time assessment to facilitate daily dose adjustment. OS, DFS, and EFS were 87%, 81%, and 69%, respectively. Median follow-up was 32.1 months (range 0.82-160 months) following transplant. Lower EFS was associated with patient age (<1 year; p = .057) and lower cumulative treosulfan dose (<42 g/m2; p = .003). Stable donor chimerism in B-cell, NK-cell, and granulocyte lineages at 1-year post-transplant were more prevalent in patients receiving thiotepa conditioning. Two infants required daily dose adjustment to treosulfan to avoid high AUC.

CONCLUSIONS

Excellent clinical outcomes and stable chimerism were observed in this patient series. The addition of thiotepa conferred no significant toxicity and trended toward sustained ongoing donor engraftment. Correlating treosulfan AUC with long-term patient outcomes is required.

HLA-haploidentical stem cell transplantation in children with inherited bone marrow failure syndromes: A retrospective analysis on behalf of EBMT severe aplastic Anemia and pediatric diseases working parties

Haploidentical stem cell transplantation (haplo-SCT) represents the main alternative for children with inherited bone marrow failure syndrome (I-BMF) lacking a matched donor. This retrospective study, conducted on behalf of the EBMT SAAWP and PDWP, aims to report the current outcomes of haplo-SCT in I-BMFs, comparing the different in vivo and ex vivo T-cell depletion approaches. One hundred and sixty-two I-BMF patients who underwent haplo-SCT (median age 7.4 years) have been registered. Fanconi Anemia was the most represented diagnosis (70.1%). Based on different T-cell depletion (TCD) approaches, four categories were identified: (1) TCRαβ+/CD19+-depletion (43.8%); (2) T-repleted with post-transplant Cyclophosphamide (PTCy, 34.0%); (3) In-vivo T-depletion with ATG/alemtuzumab (14.8%); (4) CD34+ positive selection (7.4%). The cumulative incidences (CI) of neutrophil and platelet engraftment were 84% and 76% respectively, while that of primary and secondary graft failure was 10% and 8% respectively. The 100-day CI of acute GvHD grade III-IV(95% CI) was 13%, while the 24-month CI of extensive chronic GvHD was 4%. After a median follow-up of 43.4 months, the 2-year overall survival(OS) and GvHD/Rejection-free Survival (GRFS) probabilities are 67% and 53%, respectively. The TCR CD3+αβ+/CD19+ depletion group showed a significantly lower incidence of both acute and chronic GvHD and higher OS (79%; p0.013) and GRFS (71%; p < .001), while no significant differences in outcomes have been observed by different diagnosis and conditioning regimens. This large retrospective study supports the safety and feasibility of haplo-SCT in I-BMF patients. TCRαβ+/CD19+ depletion offers higher chances of patients' survival, with a significantly lower risk of severe a- and c-GvHD in I-BMFs compared to other platforms.

Reduced toxicity (FluBu3) versus myeloablative (BuCy) conditioning in acute myeloid leukemia patients who received first allogeneic hematopoietic stem cell transplantation in measurable residual disease-negative CR1

In the present study, reduced toxicity (FluBu3) and myeloablative (BuCy) conditioning were compared in patients with AML who received first allogeneic HSCT in MRD-negative CR1. The study included 124 adult patients who underwent HSCT from an HLA-matched (8/8) sibling, unrelated, or 1-locus mismatched (7/8) unrelated donor (MMUD). The median age was 45 years and intermediate cytogenetics comprised majority (71.8%). The 2-year OS, RFS, CIR and NRM for BuCy (n = 78, 62.9%) and FluBu3 (n = 46, 37.1%) groups were 78.3% and 84.5% (p = 0.358), 78.0% and 76.3% (p = 0.806), 7.7% and 21.5% (p = 0.074) and 14.3% and 2.2% (p = 0.032), respectively. At the time of data cut-off, relapse and NRM were the main causes of HSCT failure in each of the FluBu3 and BuCy arms. Among patients, 75% of relapsed FluBu3 patients had high-risk features of either poor cytogenetics or FLT3-ITD mutation compared with 16.7% of BuCy patients. The majority of NRM in the BuCy group was due to GVHD (73%), half of whom received MMUD transplantation. To conclude, the FluBu3 reduced toxicity conditioning showed comparable post-transplant OS and RFS to BuCy and was associated with significantly reduced NRM that was offset by a trend towards higher risk of relapse even in MRD-negative CR1 population.

Mismatched related donor allogeneic haematopoietic cell transplantation compared to other donor types for Ph+ chronic myeloid leukaemia: A retrospective analysis from the Chronic Malignancies Working Party of the EBMT

Allogeneic haematopoietic cell transplantation (allo-HCT) remains an option for tyrosine kinase inhibitor-resistant chronic myeloid leukaemia (CML) in first chronic phase (CP1) and high-risk patients with advanced disease phases. In this European Society for Blood and Marrow Transplantation (EBMT) registry-based study of 1686 CML patients undergoing first allo-HCT between 2012 and 2019, outcomes were evaluated according to donor type, particularly focusing on mismatched related donors (MMRDs). Median age at allo-HCT was 46 years (IQR 36-55). Disease status was CP1 in 43%, second CP (CP2) or later in 27%, accelerated phase in 12% and blast crisis in 18%. Donor type was matched related (MRD) in 39.2%, MMRD in 8.1%, matched unrelated (MUD) in 40.2%, and mismatched unrelated (MMUD) in 12.6%. In 4 years, overall survival (OS) for MRD, MMRD, MUD and MMUD was 61%, 56%, 63% and 59% (p = 0.21); relapse-free survival (RFS) was 48%, 42%, 52% and 46% (p = 0.03); cumulative incidence of relapse (CIR) was 33%, 37%, 27% and 30% (p = 0.07); non-relapse mortality (NRM) was 19%, 21%, 21% and 24% (p = 0.21); and graft-versus-host disease (GvHD)-free/relapse-free survival (GRFS) was 16%, 18%, 22% and 15% (p = 0.05) respectively. On multivariate analysis, MMRD use associated with longer engraftment times and higher risk of graft failure compared to MRD or MUD. There was no statistical evidence that MMRD use associated with different OS, RFS and incidence of GvHD compared to other donor types.

Harmonizing definitions for hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism in allogeneic hematopoietic cell transplantation: a report on behalf of the EBMT, ASTCT, CIBMTR, and APBMT

Despite emergence of novel therapies to treat hematologic malignancies, allogeneic hematopoietic cell transplantation (allo-HCT) remains an essential treatment modality capable of curing these diseases. Allo-HCT has been also shown to be curative in benign hematologic disorders such as aplastic anemia, sickle cell disease, and thalassemia, among others. Recently, the American Society for Transplantation and Cellular Therapy (ASTCT) published standardized definitions for hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism. To attempt broader international consensus, a panel of adult and pediatric physician transplant experts was assembled from European Society for Blood and Marrow Transplantation (EBMT), ASTCT, the Center for International Blood and Marrow Transplant Research (CIBMTR), and Asia-Pacific Blood and Marrow Transplantation (APBMT). Consensus was defined as ≥70% of voting members strongly agreeing or somewhat agreeing with a definition. With few exceptions, there was a consensus to endorse the prior ASTCT definitions. Importantly, we revised existing EBMT and CIBMTR data collection forms to align with these harmonized definitions that will facilitate research and international collaboration among transplant researchers and across transplant registries.

Systemic inflammatory autoimmune disease before allogeneic hematopoietic stem cell transplantation is a risk factor for death in patients with myelodysplastic syndrome or chronic myelomonocytic leukemia

Myelodysplastic syndrome (MDS) is well known to be complicated by systemic inflammatory autoimmune disease (SIADs). However, it remains unclear how the prognosis after allogenic hematopoietic stem cell transplantation (allo-HSCT) in patients with MDS is impacted by SIADs that occur before allo-HSCT. Therefore, we hypothesized that SIADs before allo-HSCT may be a risk factor for negative outcomes after allo-HSCT in patients with MDS. We conducted a single-center, retrospective, observational study of sixty-nine patients with MDS or chronic myelomonocytic leukemia who underwent their first allo-HCT. Fourteen of the patients had SIADs before allo-HSCT. In multivariate analysis, the presence of SIADs before allo-HSCT was an independent risk factor for overall survival (HR, 3.36, 95% confidence interval: 1.34-8.42, p = 0.009). Endothelial dysfunction syndrome was identified in five of 14 patients with SIADs who required immunosuppressive therapy or intensive chemotherapy, and notably, all patients with uncontrollable SIADs at allo-HSCT developed serious endothelial dysfunction syndrome and died in the early phase after allo-HSCT. The development of SIADs in the context of MDS is thought to reflect the degree of dysfunction of hematopoietic cells in MDS and suggests a higher risk of disease progression. In addition, MDS patients with SIADs before allo-HSCT are considered to be at higher risk of endothelial dysfunction syndrome because of preexisting vascular endothelial dysfunction due to SIADs. In conclusion, SIADs before allo-HSCT constitute an independent risk factor for death in MDS patients undergoing allo-HSCT.

Music Listening in Stem Cell Transplantation and Acute Myeloid Leukemia: A Randomized Clinical Trial

CONTEXT

Music listening (ML) has been shown to have a beneficial effect on patients with cancer. However, novel intervention approaches are needed.

OBJECTIVES

We aimed to determine whether ML based on the iso-principle, conducted using a mobile application (GloMus), improves symptom burden, quality of life (QoL), anxiety, and depression in patients undergoing stem cell transplantation (SCT) and intensive induction chemotherapy for acute myeloid leukemia (AML).

METHODS

In this randomized controlled clinical trial, we assigned 71 patients to the ML or standard care (SC) groups, stratified by the reason for admission (AML, allogeneic-SCT, or inpatient/outpatient autologous-SCT). Upon admission, participants in the ML groups were invited to undergo daily ML sessions designed to change negative moods into positive ones (iso-principle). The intervention consisted of listening to pre-recorded classical music ordered by beats per minute and tonality. Symptom burden (Edmonton Symptom Assessment System-Revised) was assessed in the ML groups before and after each session. Anxiety, depression (Hospital Anxiety and Depression Scale), and QoL (Functional Assessment of Cancer Therapy-Bone Marrow Transplantation/Leukemia) were measured weekly in the ML and SC groups.

RESULTS

Symptom burden in both allogeneic- and inpatient autologous-SCT ML groups reduced after the intervention. In all experimental groups, clinically important improvements were observed after ML sessions. No differences were found between the groups (ML vs. SC) at different weeks of admission regarding anxiety, depression, and QoL.

CONCLUSIONS

ML based on our innovative iso-principle strategy, conducted using GloMus, reduced the symptom burden in patients undergoing allogeneic- and inpatient autologous-SCT (ClinicalTrials.gov number, NCT05696457).

Genetic landscape and clinical outcomes of patients with BCOR mutated myeloid neoplasms

The BCL6-corepressor (BCOR) is a tumor-suppressor gene located on the short arm of chromosome X. Data are limited regarding factors predicting survival in BCOR-mutated (mBCOR) acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). We evaluated 138 patients with mBCOR myeloid disorders, of which 36 (26.1%) had AML and 63 (45.6%) had MDS. Sixty-six (47.8%) patients had a normal karyotype while 18 (13%) patients had complex karyotype. BCOR-mutated MDS/AML were highly associated with RUNX1 and U2AF1 co-mutations. In contrast, TP53 mutation was infrequently seen with mBCOR MDS. Patients with an isolated BCOR mutation had similar survival compared to those with high-risk co-mutations by European LeukemiaNet (ELN) 2022 criteria (median OS 1.16 vs. 1.27 years, P=0.46). Complex karyotype adversely impacted survival among mBCOR AML/MDS (HR 4.12, P<0.001), while allogeneic stem cell transplant (alloSCT) improved survival (HR 0.38, P=0.04). However, RUNX1 co-mutation was associated with an increased risk of post-alloSCT relapse (HR 88.0, P=0.02), whereas melphalan-based conditioning was associated with a decreased relapse risk (HR 0.02, P=0.01). We conclude that mBCOR is a high-risk feature across MDS/AML, and that alloSCT improves survival in this population.

Neurologic Complications of the Central Nervous System after Allogeneic Stem Cell Transplantation: The Role of Transplantation-Associated Thrombotic Microangiopathy as a Potential Underreported Cause

Neurologic complications (NCs), especially those of the central nervous system (CNS), represent a severe complication after allogeneic stem cell transplantation (allo-HSCT) and are associated with relevant morbidity and mortality. We aimed to characterize the potential risk factors for the development of CNS-NC, with a special focus on the role of calcineurin inhibitors (CNIs) as a predisposing factor. For this purpose, we compared cyclosporin A (CsA) versus tacrolimus (TAC) with respect to their influence on the incidence and type of CNS-NC after allo-HSCT. We retrospectively analyzed the incidence, risk factors, and impact on outcomes of CNS-NC diagnosed during the post-transplantation follow-up in patients with different high-risk hematologic malignancies who underwent allo-HSCT at our institution over a 20-year period. All patients included in the analysis received CNI (CsA or TAC) as graft-versus-host disease (GVHD) prophylaxis. We evaluated a total of 739 consecutive patients who underwent transplantation between December 1999 and April 2019. During a median follow-up of 6.8 years, we observed a CNS-NC incidence of 17%. The development of CNS-NC was associated with decreased overall survival (OS) and increased transplantation-related mortality (TRM). The most frequent CNS-NCs were infections (30%) and neurologic adverse events related to the administration of CNI, TAC, or CsA as GVHD prophylaxis (42%). In the multivariable analysis, age, total body irradiation (TBI), and severe acute GVHD and chronic GVHD were significant risk factors in the development of CNS-NCs. TAC compared with CsA emerged as an independent predisposing factor for CNS-NCs. The TAC-associated risk of CNS-NCs was related mostly to the occurrence of transplantation-associated thrombotic microangiopathy (TA-TMA) with neurologic manifestations (neuro-TA-TMA), although the general TA-TMA incidence was comparable in the 2 CNI subgroups. CNS-NCs are associated with poor prognosis after allo-HSCT, with TAC emerging as a potential yet insufficiently characterized predisposing factor.

Toxicities associated with tyrosine kinase inhibitor maintenance following allogeneic hematopoietic cell transplantation in Philadelphia chromosome-positive acute lymphoblastic leukemia

Allogeneic hematopoietic cell transplantation (HCT) offers a potential cure in Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL); nonetheless, relapses are common and the major cause of mortality. One strategy to prevent relapse is tyrosine kinase inhibitor (TKI) maintenance post-HCT, but published clinical experience is primarily with the first-generation TKI imatinib while data with newer generation TKIs are limited. We conducted a retrospective analysis of 185 Ph+ ALL patients who underwent HCT followed by TKI maintenance from 2003 to 2021 at City of Hope. Initially, 50 (27.0%) received imatinib, 118 (63.8%) received a second-generation TKI (2G-TKI), and 17 (9.2%) received ponatinib. A total of 77 patients (41.6%) required a dose reduction of their initial TKI due to toxicity. Sixty-six patients (35.7%) did not complete maintenance due to toxicity; 69 patients (37.3%) discontinued 1 TKI, and 11 (5.9%) discontinued 2 TKIs due to toxicity. Initial imatinib versus 2G-TKI versus ponatinib maintenance was discontinued in 19 (38.0%) versus 68 (57.6%) versus 3 (17.6%) patients due to toxicity (p = .003), respectively. Patients on ponatinib as their initial TKI had a longer duration of TKI maintenance versus 2G-TKI: 576.0 days (range, 72-921) versus 254.5 days (range, 3-2740; p = .02). The most common reasons for initial TKI discontinuation include gastrointestinal (GI) intolerance (15.1%), cytopenia (8.6%), and fluid retention (3.8%). The 5-year overall survival and progression-free survival for the total population were 78% and 71%, respectively. Our findings demonstrate the challenges of delivering post-HCT TKI maintenance in a large real-world cohort as toxicities leading to TKI interruptions, discontinuation, and dose reduction were common.

Donor/recipient Rh-mismatched allogeneic hematopoietic stem cell transplantation: transfusion strategy and allo-immunization to red blood cell antigens

In the case of donor/recipient rhesus (Rh)-incompatibility after allogeneic hematopoietic stem cell transplantation (alloHSCT), the transfusion policy in France is to transfuse red blood cells (RBC) in the donor's Rh phenotype from the day of transplantation, leading to a risk of allo-immunization, either of donor or recipient origin. In this single-center retrospective study, the incidence of donor/recipient Rh incompatibility was 7.1% over an 8-year period including 1012 alloHSCT. Six of 58 evaluable patients (10.3%) developed alloantibodies to RBC antigens within one year of alloHSCT. None of these allo-immunizations were directed against the donor-mismatched Rh antigens and none could have been prevented by the transfusion of recipient and donor Rh-compatible RBC units. None of these allo-immunizations led to immune-mediated hemolytic anemia. We observed a statistically significant higher incidence of chronic GVHD among patients with anti-RBC allo-immunization. In the context of donor/recipient Rh incompatibility, the transfusion of packed RBC units in the donor's Rh phenotype from the day of alloHSCT is feasible and not associated with a high risk of allo-immunization. The generalization of this strategy could be discussed even when donor and recipient Rh phenotypes could be respected, to allow the preservation of units of infrequent phenotypes for other indications.

Association of the pre-transplant CD4/CD8 ratio with the prognosis following allogeneic hematopoietic stem cell transplantation

The tumor microenvironment's cells can promote or inhibit tumor formation, and there are no reports on the CD4/CD8 ratio's association with outcomes post allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively evaluated the pre-transplant peripheral blood CD4/CD8 ratio in 168 patients who underwent their first allo-HSCT for hematological malignancies at our institution. When patients were divided into two groups according to the median CD4/CD8 ratio 1.35 (range, 0.09-19.89), the high CD4/CD8 ratio group had a higher incidence of relapse, equivalent non-relapse mortality and worse overall survival (OS) than the low CD4/CD8 ratio group. In a multivariate analysis, the CD4/CD8 ratio was significantly associated with an increased risk of relapse, although there was a marginally significant difference in OS. The pre-transplant peripheral blood CD4/CD8 ratio could be a novel biomarker for predicting the prognosis of allo-HSCT.

Posttransplant cyclophosphamide versus anti-thymocyte globulin versus combination for graft-versus-host disease prevention in haploidentical transplantation for adult acute myeloid leukemia: A report from the European Society for Blood and Marrow Transplantation Acute Leukemia Working Party

BACKGROUND

The optimal choice for graft-versus-host disease (GVHD) prophylaxis in haploidentical stem cell transplantation (haplo-SCT) remains debatable. Posttransplant cyclophosphamide (PTCy) and anti-thymocyte globulin (ATG) are two common strategies, but little is known about their combination.

METHODS

Using the European Society for Blood and Marrow Transplantation (EBMT) registry, the authors identified 3649 adult patients with acute myeloid leukemia (AML) who underwent haplo-SCT in complete remission between 2007 and 2021 at 260 EBMT-participating centers who received either PTCy (n = 2999), ATG (n = 358), or combination prophylaxis (n = 292). Cord blood transplants, combined bone marrow and peripheral grafts, and transplants with ex vivo graft manipulation were excluded. Median follow-up was 31.8 months.

RESULTS

On multivariate analysis, adjusting for patient age and performance status, disease status at transplant, cytogenetic risk, conditioning intensity, stem cell source, female-to-male graft, and donor and patient CMV status, we present the following. Compared to PTCy, ATG had a higher risk of nonrelapse mortality (hazard ratio [HR], 1.6; p = .003), worse leukemia-free survival (HR, 1.4; p = .002), overall survival (HR, 1.49; p = .0009), and GVHD-free and relapse-free survival (HR, 1.29; p = .012). The combination of PTCy and ATG, however, led to significantly reduced rates of grade 2-4 (HR, 0.51; p = .0003) and grade 3-4 (HR, 0.5; p = .018) acute GVHD and did not affect any transplant outcomes compared to PTCy without ATG.

CONCLUSION

The authors conclude that ATG alone is a less effective prophylaxis strategy compared to PTCy, however, the combination of PTCy and ATG is superior to either monotherapy. They propose that this combination could be considered a potential new standard of care for GVHD prophylaxis in haplo-SCT for AML.

Acute pulmonary injury in hematology patients supported with pathogen-reduced and conventional platelet components

ABSTRACT

Patients treated with antineoplastic therapy often develop thrombocytopenia requiring platelet transfusion, which has potential to exacerbate pulmonary injury. This study tested the hypothesis that amotosalen-UVA pathogen-reduced platelet components (PRPCs) do not potentiate pulmonary dysfunction compared with conventional platelet components (CPCs). A prospective, multicenter, open-label, sequential cohort study evaluated the incidence of treatment-emergent assisted mechanical ventilation initiated for pulmonary dysfunction (TEAMV-PD). The first cohort received CPC. After the CPC cohort, each site enrolled a second cohort transfused with PRPC. Other outcomes included clinically significant pulmonary adverse events (CSPAE) and the incidence of treatment-emergent acute respiratory distress syndrome (TEARDS) diagnosed by blinded expert adjudication. The incidence of TEAMV-PD in all patients (1068 PRPC and 1223 CPC) was less for PRPC (1.7 %) than CPC (3.1%) with a treatment difference of -1.5% (95% confidence interval [CI], -2.7 to -0.2). In patients requiring ≥2 PCs, the incidence of TEAMV-PD was reduced for PRPC recipients compared with CPC recipients (treatment difference, -2.4%; 95% CI, -4.2 to -0.6). CSPAE increased with increasing PC exposure but were not significantly different between the cohorts. For patients receiving ≥2 platelet transfusions, TEARDS occurred in 1.3% PRPC and 2.6% CPC recipients (P = .086). Bayesian analysis demonstrated PRPC may be superior in reducing TEAMV-PD and TEARDS for platelet transfusion recipients compared with CPC recipients, with 99.2% and 88.8% probability, respectively. In this study, PRPC compared with CPC demonstrated high probability of reduced severe pulmonary injury requiring assisted mechanical ventilation in patients with hematology disorders dependent on platelet transfusion. This trial was registered at www.ClinicalTrials.gov as #NCT02549222.

The impact of infused red blood cell volume on major and bidirectional ABO-mismatched bone marrow transplantation

BACKGROUND AIMS

ABO incompatibility does not hinder bone marrow transplantation (BMT), but it has been associated with worse outcomes and additional adverse events. This study aimed to verify the impact of incompatible red blood cells (iRBCs) in allogeneic BMT and to determine a safe number of iRBCs to be infused.

METHODS

We compared ABO-incompatible (iABO) allogeneic BMT (n = 42) with ABO-compatible allogeneic BMT (n = 44) and evaluated the impact of the number of infused iRBCs on outcomes and adverse events.

RESULTS

The iABO patients demonstrated delayed time to transfusion independence at 30 days and 60 days, increased requirement for red blood cell (RBC) transfusion and greater hemolysis signals and incidence of pure red cell aplasia. Neutrophil/platelet engraftment, length of hospitalization post-transplant, platelet units required, graft-versus-host disease occurrence and overall survival were similar in both groups. Patients in the iABO group received 1.03 × 1010 iRBCs/kg (range, 0.36-3.88). Infusion of iRBCs >1.0 × 1010 /kg was related to graft failure or death before neutrophil engraftment or platelet engraftment or both as well as increased plasma requirement and increased creatinine. Our results also suggest that antibody titers impact the transplantation scenario.

CONCLUSIONS

The iABO transplantation showed some unfavorable outcomes. It is important to monitor the value of iRBCs to be infused, considering the recipient antibody titers. We propose using the number of iRBCs (iRBCs/kg) as a dose parameter with regard to infused iRBCs. Further studies are necessary to clarify the maximum safe number of iRBCs in iABO transplants.

Prognostic impact of the conditioning intensity on outcomes after allogeneic transplantation for MDS with low blasts: a nationwide retrospective study by the adult MDS working group of the Japan Society for Transplantation and Cellular Therapy

Poor prognostic factors, such as transfusion dependency and chromosomal risk, need to be considered in the indication of allogeneic hematopoietic cell transplantation (allo-HCT) for patients harboring myelodysplastic syndromes with less than 5% marrow blasts (MDS-Lo). We analyzed the post-transplant outcomes of 1229 MDS-Lo patients who received myeloablative (MAC)(n = 651), reduced-intensity (RIC)(n = 397), and non-myeloablative conditioning (NMAC) regimens (n = 181). The multivariate analysis revealed that the RIC group had better chronic graft-versus-host disease (GVHD)- and relapse-free survival (CRFS) (P = 0.021), and GVHD- and relapse-free survival (GRFS) than the MAC group (P = 0.001), while no significant differences were observed between the NMAC and MAC groups. In the subgroup analysis, the MAC group has better overall survival (P = 0.008) than the RIC group among patients with an HCT-comorbidity index (HCT-CI) score of 0, while the RIC group had better overall survival (P = 0.029) than the MAC group among those with an HCT-CI score ≥3. According to the type of conditioning regimen, total body irradiation 12 Gy-based MAC regimen showed better OS and CRFS than the other MAC regimen, and comparable outcomes to the RIC regimen. In conclusion, the RIC and NMAC regimens are promising options for MDS-Lo patients in addition to the MAC regimen.

Impact of Different Fludarabine Doses in the Fludarabine-Based Conditioning Regimen for Unrelated Bone Marrow Transplantation

The purine analog fludarabine (Flu) plays a central role in reduced-intensity conditioning and myeloablative reduced-toxicity conditioning regimens because of limited nonhematologic toxicities. Few reports assess the impact of different dose of Flu on the clinical outcomes and the Flu doses vary across reports. To compare the effect of Flu dose, the clinical outcomes of patients who received Flu and busulfan (FB; n = 1647) or melphalan (Flu with melphalan (FM); n = 1162) conditioning for unrelated bone marrow transplantation were retrospectively analyzed using Japanese nationwide registry data. In the FB group, high-dose Flu (180 mg/m2; HFB) and low-dose Flu (150/125 mg/m2; LFB) were given to 1334 and 313 patients, respectively. The 3-year overall survival (OS) rates were significantly higher in the HFB group than in the LFB group (49.5% versus 39.2%, P < .001). In the HFB and LFB groups, the cumulative incidences were 30.4% and 36.6% (P = .058) for 3-year relapse and 25.1% and 28.1% (P = .24) for 3-year nonrelapse mortality (NRM), respectively. In the multivariate analysis for OS and relapse, Flu dose was identified as an independent prognostic factor (hazard ratio: 0.83, P = .03; hazard ratio: 0.80, P = .043). In the FM group, high-dose Flu (180 mg/m2; HFM) and low-dose Flu (150/125 mg/m2; LFM) were given to 118 and 1044 patients, respectively. The OS, relapse, and NRM after 3 years did not differ significantly between the HFM and LFM groups (48.3% versus 48.8%, P = .92; 23.7% versus 27.2%, P = .55; 31.9% versus 30.8%, P = .67). These findings suggest that high-dose Flu was associated with favorable outcomes in the FB group but not in the FM group.

Improvements in Posttransplant Outcomes Over Two Decades in Older Patients with Acute Myeloid Leukemia in the EBMT ALWP Study

PURPOSE

Acute myeloid leukemia (AML) is a disease of older patients. Progress in allogeneic hematopoietic cell transplantation (allo-HCT) allowed the delivery of allo-HCT to older patients. We assessed changes over time in transplant characteristics and outcomes in patients with AML ages 65 years and above.

PATIENTS AND METHODS

We identified 7,215 patients with AML (median age 68 years, range 65-80) allografted between 2000 and 2021 in first complete remission (CR1; 64%), second or subsequent remission (CR2+; 14%), or active disease (22%).

RESULTS

Median follow-up was 40 months. The 3-year cumulative relapse incidence (RI) gradually and significantly decreased from 37% to 31%, then to 30% (P = 0.001) over the three time periods (2000-2009; 2010-2014; 2015-2021), whereas nonrelapse mortality (NRM) decreased from 31% and 31% to 27% (P = 0.003). The 3-year leukemia-free survival (LFS) and overall survival (OS) gradually and significantly improved from 32% to 38%, and then to 44% (P = 0.001) and from 37% to 42%, and then to 49% (P = 0.001), respectively. In multivariate analysis, significant improvement in the RI, LFS, and OS were noted after 2015, whereas NRM was not significantly affected. This improvement was observed regardless of disease status at transplant.

CONCLUSIONS

In older patients with AML, we observed an impressive improvement over time in posttransplant outcomes, mostly attributed to decreased RI rather than decreased NRM, and regardless of disease status at transplant. These large-scale, real-world data can serve as a benchmark for future studies in this setting and indicate that the opportunity for transplant for the elderly should be mandatory and no longer an option.

Treosulfan is a safe and effective alternative to busulfan for conditioning in adult allogeneic HSCT patients: Data from a single center

INTRODUCTION

Type of conditioning regimen impacts the outcome of patients who undergo allogeneic HSCT since graft versus host disease (GVHD), infections, regimen related toxicities (RRT) are important causes of post-transplant mortality. Despite the RRT profile of busulfan, it is frequently used worldwide. Treosulfan has advantages in terms of dose of administration, lower incidence of sinusoidal obstruction syndrome and lower neurotoxicity. We retrospectively investigated outcomes of patients who underwent allogeneic HSCT with treosulfan or busulfan based conditioning regimens in our institution.

METHODS

Treosulfan was administered to 94 patients while 85 patients received busulfan. Our outcomes were RRT, chronic and acute GVHD, relapse related mortality (RRM), non-relapse mortality, and fungal infection. The clinical follow up data, regarding the primary and secondary endpoints of our study, of the patients who received treosulfan or busulfan based conditioning regimens were statistically analyzed.

RESULTS

The median follow-up was 14 months for the treosulfan group while it was 11 months for the busulfan group (p = 0.16). RRT was 11.7% and 7.1% for treosulfan and busulfan respectively. The incidence of extensive chronic GVHD was less frequent in the treosulfan group compared to the busulfan group (15.7% vs. 32.1%) (p < 0.001). The incidence of acute GVHD (Grade 3 or higher) was 32.2% in the treosulfan group while it was 31.6% in the busulfan group. The RRM was 17% in the treosulfan group while it was 34% in the busulfan group. The non-relapse mortality was 35.5% and 29.4% in the treosulfan group and in the busulfan group respectively (p = 0.962).

CONCLUSION

Treosulfan, with a lower RRM, lower chronic GVHD incidence and with a similar RRT profile appears to be a safe alternative to busulfan.

Peripheral blood stem cell transplantation using HLA-haploidentical donor with post-transplant cyclophosphamide versus HLA-matched sibling donor for lymphoma

Data comparing HLA-haploidentical donors and HLA-matched sibling donors (MSDs) in peripheral blood stem cell transplantation (PBSCT) for lymphoma are scarce. We retrospectively analyzed 465 patients with lymphoma aged 16 years or older who underwent PBSCT using haploidentical donors with post-transplant cyclophosphamide (PTCy-haplo) (n = 166) or MSDs with calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis (n = 299). Two-year overall survival (OS), progression-free survival (PFS), and GVHD-free, relapse-free survival (GRFS) in the PTCy-haplo and MSD groups were 49.2% versus 51.9% (P = 0.64), 38.0% versus 39.9% (P = 0.97), and 27.7% versus 18.5% (P = 0.006), respectively. In multivariable analyses, PTCy-haplo recipients had slower neutrophil recovery (hazard ratio [HR], 0.62; P < 0.001) and platelet recovery (HR, 0.54; P < 0.001), lower risk of chronic GVHD (HR, 0.64; P = 0.038) and extensive chronic GVHD (HR, 0.45; P = 0.008), and better GRFS (HR, 0.66; P = 0.003) than MSD transplant recipients. OS, PFS, relapse or progression, and non-relapse mortality were similar between the groups. The difference might be mainly due to PTCy use rather than donor type; however, the results suggested that PTCy-haplo could be a possible option as an alternative to conventional MSD transplantation for lymphoma in PBSCT.

Autotaxin is a potential predictive marker for the development of veno-occlusive disease/sinusoidal obstruction syndrome after allogeneic hematopoietic cell transplantation

Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a life-threatening complication after allogeneic hematopoietic cell transplantation (allo-HCT), and stratification of the high-risk group before transplantation is significant. Serum autotaxin (ATX) levels have been reported to increase in patients with liver fibrosis caused by metabolic inhibition from liver sinusoidal endothelial cells. Considering that the pathophysiology of VOD/SOS begins with liver sinusoidal endothelial cell injury, an increase in serum ATX levels may precede the onset of VOD/SOS. A retrospective study with 252 patients, including 12 patients with VOD/SOS, who had received allo-HCT was performed. The cumulative incidence of VOD/SOS was higher in the group with serum ATX levels before conditioning (baseline ATX) above the upper reference limit (high ATX group, p < 0.001), and 1-year cumulative incidences were 22.7% (95% confidence interval [95%CI], 3.1-42.4%) and 3.5% (95%CI, 1.1-5.8%), respectively. In the multivariate analysis, elevated baseline ATX was identified as an independent risk factor for VOD/SOS development and showed an additive effect on the predictive ability of known risk factors. Furthermore, the incidence of VOD/SOS-related mortality was greater in the high ATX group (16.7% vs. 1.3%; p = 0.005). Serum ATX is a potential predictive marker for the development of VOD/SOS.

Clinical effects of tacrolimus blood concentrations early after allogeneic hematopoietic stem cell transplantation

BACKGROUND AIMS

Tacrolimus (TAC) plus short-term methotrexate (stMTX) is used for graft-versus-host disease (GVHD) prophylaxis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). TAC blood concentrations are frequently adjusted to enhance the graft-versus-leukemia/lymphoma effect or attenuate severe GVHD. Limited information is available on the clinical impact of these adjustments and the optimal time to perform them in order to achieve good clinical outcomes.

METHODS

We retrospectively analyzed 211 patients who underwent allo-HSCT at our institutes.

RESULTS

Higher TAC concentrations in week 3 correlated with a significantly higher cumulative incidence of relapse (CIR) (P = 0.03) and lower nonrelapse mortality (P = 0.04). The clinical impact of high TAC concentrations in week 3 on CIR was detected in the refined disease risk index: low/intermediate (P = 0.04) and high (P < 0.01), and conditioning regimens other than cyclophosphamide/total body irradiation and busulfan/cyclophosphamide (P = 0.07). Higher TAC concentrations in week 1 correlated with a lower grade 2-4 acute GVHD rate (P = 0.01). Higher TAC concentrations in weeks 2 and 3 correlated with slightly lower (P = 0.05) and significantly lower (P = 0.02) grade 3-4 acute GVHD rates, respectively. Higher TAC concentrations in weeks 1 and 3 were beneficial for severe acute GVHD in patients with a human leukocyte antigen-matched donor (P = 0.03 and P < 0.01, respectively), not treated with anti-thymocyte globulin (P = 0.02 and P = 0.02, respectively), and receiving three stMTX doses (P = 0.03 and P = 0.02, respectively).

CONCLUSIONS

The clinical impact of TAC concentrations varied according to patient characteristics, including disease malignancy, conditioning regimens, donor sources, and GVHD prophylaxis. These results suggest that TAC management needs to be based on patient profiles.

Clinical features of immature leukemias in children

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL), mixed phenotypic acute leukemia (MPAL), and acute myeloid leukemia with minimal differentiation (AML-M0) all originate from immature hematopoietic progenitor cells and have a poor prognosis. We investigated the clinical characteristics of these immature leukemias in 17 children (ETP-ALL: 8, MPAL: 5, AML-M0: 4) at seven institutions. Clinical and laboratory findings were comparable across disease types. Eleven and six patients received ALL- and AML-oriented induction chemotherapy, with six and four achieving complete remission (CR), respectively. Five additional patients achieved CR after salvage with the other type of chemotherapy. Eight patients received hematopoietic cell transplantation (HCT) in first CR, and six survived without relapse. However, six of seven patients who did not receive HCT during first CR relapsed; all underwent HCT later, and only three survived. The 5-year event-free survival (EFS) and overall survival (OS) rate were 37% and 69%, respectively. Patients who achieved CR after induction chemotherapy and received HCT in first CR had favorable EFS and OS. Notably, all patients who received HCT in first CR survived 5 years after diagnosis. Appropriate induction chemotherapy and HCT in first CR could improve the outcome of immature leukemias.

Treosulfan- Versus Busulfan-based Conditioning in Allogeneic Hematopoietic Cell Transplantation for Myelodysplastic Syndrome: A Single-center Retrospective Propensity Score-matched Cohort Study

Treosulfan has shown promise in allogeneic hematopoietic cell transplantation (HCT) for its myeloablative properties and low toxicity. In this single-center retrospective propensity score-matched cohort study we compared treosulfan- and busulfan-based conditioning in allogeneic HCT for patients with myelodysplastic syndrome (MDS). This study included 138 adults who underwent allogeneic HCT for MDS or chronic myelomonocytic leukemia at Princess Margaret Hospital, Toronto, from 2015 to 2022. Using propensity score matching, we compared transplant outcomes between 2 well-matched cohorts who received conditioning with either fludarabine-treosulfan (FT) (n = 46) or fludarabine-busulfan with total body irradiation (FBT200) (n = 92). A scoring system based on patient age, Karnofsky performance score, and hematopoietic cell transplant comorbidity index was used to assign patients based on fitness to low-dose (30 g/m2) or high-dose (42 g/m2) treosulfan: 32 (69.6%) received high-dose treosulfan. The racial composition of the 2 groups was similar, with 27.2% and 21.7% of FBT200 and FT recipients, respectively, identifying as non-Caucasian (P = .61). Primary outcomes were analyzed at a median follow-up of 747 days. Of all participants, 116 (84.0%) received graft-versus-host disease (GVHD) prophylaxis with post-transplant cyclophosphamide (PTCY) and antithymocyte globulin (ATG). Patients who received FT had a superior 2-year overall survival (OS) compared to those who received FBT200: 66.9% (95% confidence interval (CI): 46.1 to 81.2) versus 44.5% (95% CI: 34 to 54.4), hazard ratio (HR): 0.43, 95% CI: 0.22 to 0.84 (P = .013). In multivariate analysis (MVA), only the use of fresh grafts (P = .02) and FT (P = .01) were associated with improved OS. FT was associated with superior 2-year relapse-free survival (RFS) compared to FBT200: 63.1% (95% CI: 42.6 to 77.9) versus 39.1% (95% CI: 29.1 to 49.1), HR: 0.44 (95% CI: 0.24 to 0.81), P = .008. In MVA, the use of fresh grafts (P = .03) and FT (P = .009) were associated with improved RFS. Recipients of FT demonstrated superior 2-year graft-versus-host disease relapse-free survival (GRFS) compared to those who received FBT200: 57.4% (95% CI: 37.8 to 72.8) versus 35.1% (95% CI: 25.5 to 45). In MVA, only FT was associated with superior GRFS (P = .02). FT recipients exhibited markedly superior 1-year event-free survival compared to recipients of FBT200 in univariate analysis (40.3% (95% CI: 25.9 to 54.2) versus 9.2% (95% CI: 4.4 to 16.3), HR: 0.47 (95% CI: 0.30 to 0.72), P < .001) and MVA (P = .004). FT was associated with lower 1-year nonrelapse mortality compared to FBT200 in univariate analysis (9.9% (95% CI: 3.0 to 21.8) versus 29.7% (95% CI: 20.6 to 39.3), HR: 0.41 (95% CI: 0.17 to 0.96), P = .04) and MVA (P = .04). Our study utilized propensity score matching to demonstrate superiority of treosulfan- over busulfan-based conditioning in stem cell transplantation of patients with MDS and is the first to evaluate the performance of treosulfan-based conditioning in combination with ATG and PTCY. As such, it contributes to the increasing body of evidence supporting the safety of treosulfan, even at the dose of 42 g/m2.

Post-Transplant Cyclophosphamide versus Anti-Thymocyte Globulin in Patients with Hematological Malignancies Treated with Allogeneic Hematopoietic Stem Cell Transplantation from Haploidentical and Matched Unrelated Donors: A Real-Life Experience

Background: Post-transplant cyclophosphamide (PTCY) is widely used as graft versus host disease (GvHD) prophylaxis in allogeneic hematopoietic stem cell transplant (HSCT) recipients, with reported clinical benefits in patients who underwent transplant from a matched unrelated donor (MUD). However, real-life data on clinical efficacy and safety of PTCY in haploidentical and MUD transplantations are still poor. Methods: In our real-life retrospective observational study, we included a total of 40 consecutive adult patients who underwent haploidentical or MUD HSCT for various hematological malignancies and who received PTCY (n = 24) or ATG (n = 16) as GvHD prophylaxis at Hematology Units from hospitals of Salerno and Avellino, Italy, and clinical outcomes were compared. Results: We showed protective effects of PTCY against disease relapse with the relapse rate after transplantation of 16% versus 50% in the ATG arm (p = 0.02). All-cause mortality was lower (36% vs. 75%; p = 0.02) and the 2-year overall survival was slightly superior in patients administered PTCY (61% vs. 42%; p = 0.26). Conclusions: We support the use of PTCY, even in a real-life setting; however, the optimization of this protocol should be further investigated to better balance relapse prevention and GvHD prophylaxis.

Lymphocyte Crossmatch Testing or Donor HLA-DP and -DQ Allele Typing Effectiveness in Single Cord Blood Transplantation for Patients With Anti-HLA Antibodies Other Than Against HLA-A, -B, -C, and -DRB1

Anti-human leukocyte antigen (HLA) antibodies other than those against HLA-A, -B, -C, and DRB1 are a risk factor for engraftment delay and failure, especially in cord blood transplantation (CBT). The primary objective of this study was to assess the impact of the presence of anti-HLA antibodies on CBT and to evaluate the utility of lymphocyte crossmatch testing or additional HLA-DP and -DQ typing of CB units in improving transplant outcomes. We retrospectively assessed the engraftment rates and transplant outcomes of 772 patients who underwent their first CBT at our hospital between 2012 and 2021. Donors were routinely typed for HLA-A, -B, -C, and-DRB1 alleles, and the anti-HLA antibodies of recipients were screened before donor selection in all cases. Among patients who had antibodies against other than HLA-A, -B, -C, and DRB1 (n = 58), lymphocyte crossmatch testing (n = 32) or additional HLA-DP/-DQ alleles typing of CB (n = 15) was performed to avoid the use of units with corresponding alleles. The median patient age was 57 years (16 to 77). Overall, 75.7% had a high-risk disease status at transplantation, 83.5% received myeloablative conditioning regimens, and >80% were heavily transfused. Two hundred twenty-nine of the 772 recipients (29.6%) were positive for anti-HLA antibodies. There were no statistical differences in the number of infused CD34-positive cells between the anti-HLA antibody-positive and the anti-HLA antibody-negative patients. Of the 229 patients with anti-HLA antibodies, 168 (73.3%) had antibodies against HLA-A, -B, -C, and-DRB1 (Group A), whereas 58 (25.3%) had antibodies against HLA-DP, HLA-DQ, or -DRB3/4/5 with or without antibodies against HLA-A, -B, -C, and -DRB1 (Group B). No patients in both Groups A and B exhibited donor-specific anti-HLA antibodies against HLA-A, -B, -C, and -DRB1. The neutrophil engraftment rate was lower in patients with anti-HLA antibodies than in those without antibodies (89.9% versus 94.1%), whereas nonrelapse mortality (NRM) before engraftment was higher in antibody-positive patients (9.6% versus 4.9%). In patients who received 2 or more HLA allele-mismatched CB in the host-versus-graft (HVG) direction (n = 685), the neutrophil engraftment rate was lower in the anti-HLA antibody-positive recipients than in the antibody-negative recipients with significant differences (88.8% versus 93.8%) (P = .049). Similarly, transplant outcomes were worse in the antibody-positive patients with respect to 2-year overall survival (OS) (43.1% versus 52.3%) and NRM (44.0% versus 30.7%) than in the antibody-negative patients. In contrast, the results of Group B were comparable to those of the antibody-negative patients, while those of Group A were statistically worse than the antibody-negative patients in terms of all engraftment rate (88.6%), OS (34.2%), and NRM (49.0%). The presence of anti-HLA antibodies negatively impacts engraftment, NRM, and OS in CBT. However, HLA-DP/-DQ allele typing of CB units or lymphocyte crossmatch testing could be a useful strategy to overcome poor engraftment rates and transplant outcomes, especially in patients with anti-HLA antibodies against HLA-DP, HLA-DQ, or -DRB3/4/5.

Post-transplant cyclophosphamide, calcineurin inhibitor, and mycophenolate mofetil compared to anti-thymocyte globulin, calcineurin inhibitor, and methotrexate combinations as graft-versus-host disease prophylaxis post allogeneic stem cell transplantation from sibling and unrelated donors in patients with acute myeloid leukemia: a study on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Post-transplant cyclophosphamide plus calcineurin inhibitor (CNI)(tacrolimus or cyclosporine A) plus mycophenolate mofetil (PTCy/TAC or CSA/MMF) and anti-thymocyte globulin plus CNI (tacrolimus or cyclosporine A) plus methotrexate (ATG/TAC or CSA/MTX) are common graft-versus-host disease (GVHD) prophylaxis regimens. We compared the two regimens in patients with acute myeloid leukemia (AML) undergoing allogeneic transplantation from matched siblings or unrelated donors. 402 received PTCy/TAC or CSA/MMF and 5648 received ATG/TAC or CSA/MTX. Patients in the PTCy-based group were younger (48.7 vs. 51.5 years, p = 0.024) and there was a higher frequency of patient cytomegalovirus seropositivity and female donor to male patient combination in this group (77.8% vs. 71.8%, p = 0.009 and 18.4% vs. 14.4%, p = 0.029, respectively). More patients in the PTCy-based group received reduced-intensity conditioning (51.5% vs. 41%, p < 0.0001). No differences were observed in the incidence of acute GVHD grade II-IV and III-IV (21.2% vs. 20.4%, p = 0.92 and 8.1% vs. 6%, p = 0.1) or 2-year total and extensive chronic GVHD (33.7% vs. 30%, p = 0.09 and 10.7% vs. 11.2%, p = 0.81) between the groups. In the multivariate analysis, all transplant outcomes did not differ between the groups. PTCy/CNI/MMF and ATG/CNI/MTX are alternative regimens for GVHD prophylaxis in AML patients.

Late Relapse after Allogeneic Stem Cell Transplantation in Patients Treated for Acute Myeloid Leukemia: Relapse Incidence, Characteristics, Role of Conditioning Regimen, and Outcome

Late relapse, beyond 2 years following alloHSCT for AML, is rare. Among the 376 patients allografted for AML in our center between 1990 and 2016, 142 (38%) relapsed. The majority (68%) of relapses occurred during the first year following transplantation. Beyond 2 years after alloHSCT, relapse was observed in 26 patients, representing 6.9% of the whole transplanted cohort and 18.3% of the relapsing patients. Cytogenetics at relapse was available in 21 patients and remained for 15 of them concordant to that at diagnosis. The majority (85.7%) of the patients were in CR prior to transplant. Thirteen patients had grade 1-2 acute GvHD, while 13 other patients had grade 3-4 acute GvHD. None of these patients subsequently developed chronic GvHD. In multivariate analyses, a predictive factor of the absence of relapse 2 years after transplantation was the development of extensive chronic GVHD. Salvage therapy achieved new CR in 77% of these patients. We conclude that late relapse can affect a significant minority of patients allografted for AML, and the intensity of the conditioning regimen does not seem to have an impact on these relapses. Moreover, we were able to show that those patients can receive effective salvage therapy.

Donor KIR genotype based outcome prediction after allogeneic stem cell transplantation: no land in sight

Optimizing natural killer (NK) cell alloreactivity could further improve outcome after allogeneic hematopoietic cell transplantation (alloHCT). The donor's Killer-cell Immunoglobulin-like Receptor (KIR) genotype may provide important information in this regard. In the past decade, different models have been proposed aiming at maximizing NK cell activation by activating KIR-ligand interactions or minimizing inhibitory KIR-ligand interactions. Alternative classifications intended predicting outcome after alloHCT by donor KIR-haplotypes. In the present study, we aimed at validating proposed models and exploring more classification approaches. To this end, we analyzed samples stored at the Collaborative Biobank from HLA-compatible unrelated stem cell donors who had donated for patients with acute myeloid leukemia (AML) or myelodysplastic neoplasm (MDS) and whose outcome data had been reported to EBMT or CIBMTR. The donor KIR genotype was determined by high resolution amplicon-based next generation sequencing. We analyzed data from 5,017 transplants. The median patient age at alloHCT was 56 years. Patients were transplanted for AML between 2013 and 2018. Donor-recipient pairs were matched for HLA-A, -B, -C, -DRB1, and -DQB1 (79%) or had single HLA mismatches. Myeloablative conditioning was given to 56% of patients. Fifty-two percent of patients received anti-thymocyte-globulin-based graft-versus-host disease prophylaxis, 32% calcineurin-inhibitor-based prophylaxis, and 7% post-transplant cyclophosphamide-based prophylaxis. We tested several previously reported classifications in multivariable regression analyses but could not confirm outcome associations. Exploratory analyses in 1,939 patients (39%) who were transplanted from donors with homozygous centromeric (cen) or telomeric (tel) A or B motifs, showed that the donor cen B/B-tel A/A diplotype was associated with a trend to better event-free survival (HR 0.84, p=.08) and reduced risk of non-relapse mortality (NRM) (HR 0.65, p=.01). When we further dissected the contribution of B subtypes, we found that only the cen B01/B01-telA/A diplotype was associated with a reduced risk of relapse (HR 0.40, p=.04) while all subtype combinations contributed to a reduced risk of NRM. This exploratory finding has to be validated in an independent data set. In summary, the existing body of evidence is not (yet) consistent enough to recommend use of donor KIR genotype information for donor selection in routine clinical practice.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia with BCR::ABL1 fusion

BCR::ABL1 fusion is found in < 1% of de novo acute myeloid leukemia (AML) cases and confers a poor prognosis. This Japanese nationwide survey analyzed patients with AML (n = 22) and mixed phenotype acute leukemia (MPAL) (n = 10) with t(9;22) or BCR::ABL1 who underwent allogeneic hematopoietic cell transplantation (allo-HCT) between 2002 and 2018. The 3-year overall survival (OS) rates were 81.3% and 56.0%, respectively (p = 0.15), and leukemia-free survival (LFS) rates were 76.2% and 42.0%, respectively (p = 0.10) in patients with AML and MPAL. The relapse rates were 9.5% and 14.0% (p = 0.93), and the non-relapse mortality (NRM) rates were 14.3% and 44.0%, respectively (p = 0.10) in patients with AML and MPAL. One in 17 patients with AML, with pre-transplant tyrosine kinase inhibitors (TKI), and three in five patients with AML, without pre-transplant TKI, did not achieve complete remission (CR) before allo-HCT (p = 0.024). Among the 20 patients with known disease status after allo-HCT, 95.0% were in hematological or molecular CR. None of the four patients who received post-transplant TKI for prophylaxis or measurable residual disease relapse experienced hematological relapse. In conclusion, our results suggest that pre-transplant TKI could improve disease status before allo-HCT. Moreover, allo-HCT resulted in high OS, high LFS, low relapse, and low NRM rates in patients with AML with BCR::ABL1.

Oral complications in a paediatric graft versus host disease (GVHD) clinic: A retrospective study

OBJECTIVE

The aim of this study was to investigate the oral health status among allogeneic transplant recipients who were seen in a multidisciplinary graft-versus-host disease paediatric clinic at the University of California, San Francisco (UCSF).

METHODS

This was a retrospective cohort study of patients who underwent allogeneic transplants and were seen in the graft-versus-host disease paediatric clinic between January 2010 and September 2021. Demographic, medical and oral health data were recorded and analysed using descriptive statistics.

RESULTS

A total of 25 patients were seen in the paediatric graft-versus-host disease clinic (68% males) with a median age of 12 years at the time of transplant were included. Among them, 12 patients (48%) were diagnosed with oral chronic GVHD, 11 (44%) with dry mouth, four (16%) with oral pseudomembranous candidiasis, one (4%) with recrudescent Herpes Simplex Virus (HSV) infection and one (4%) with mammalian target of rapamycin-inhibitor stomatitis and were managed by the oral medicine team, accordingly with medications, such as topical steroids (44%) and anti-fungal (20%).

CONCLUSIONS

HSCT recipients may present with a variety of oral complications. Patients may benefit by a multi-disciplinary approach including a dental specialist as part of the cancer care team.

The paradigm of total body irradiation in acute lymphoblastic leukaemia: Therapeutic effectiveness versus the challenges of toxicity

INTRODUCTION

Total body irradiation (TBI) is part of the myeloablative conditioning for hematopoietic stem cell transplantation (HSCT) in malignant hematologic disorders. This therapy has recently shown improved survival in acute lymphoblastic leukemia (ALL) compared to chemotherapy-based regimens. However, side effects are a significant limitation, especially in the pediatric population.

PATIENTS AND METHODS

We retrospectively analyzed the survival of patients with ALL who underwent an HSCT at a tertiary hospital between 1996 and 2009 (N = 69 HSCT in 57 patients). We differentiated a cohort that received TBI (N = 44) from another that did not (N = 25). Subsequently, we interviewed the survivors from the TBI group with a minimum of 10 years of follow-up (N = 18), asking about the presence of side effects.

RESULTS

The overall survival (OS) at 2 and 5 years was 79.1% and 65.2% respectively for the TBI group and 66.2% and 55.8% for the non-TBI group, although this difference was not significant (P=.31). The event-free survival (EFS) at 2 and 5 years was 77.3% and 63.6% respectively for the TBI group and 56% and 32% for the non-TBI group (P=.02). The probability of relapse (PR) at 2 years for those who received TBI was 10% compared to 28.6% for those who did not receive TBI (P=.005). Survivors who received TBI developed secondary neoplasms (39%), dyslipidemia (67%), cognitive impairments affecting memory (44%), recurrent respiratory infections (39%), thyroid abnormalities (45%), premature ovarian failure (89%), cataracts (22%), and psychological problems (44%). However, the quality of life, as self-assessed by the patients, was considered good for 83% of the participants..

CONCLUSIONS

Patients who received TBI had significantly higher EFS and lower PR. However, adverse effects are frequent and significant, although they do not subjectively affect quality of life.

A Nationwide Retrospective Analysis of Allogeneic Hematopoietic Stem Cell Transplantation for Adult Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder characterized by systemic hyperinflammation. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only potentially curative treatment for primary and relapsed/refractory HLH, the optimal strategy has not been established. We retrospectively analyzed 56 adult patients (≥18 years) with primary and secondary HLH (mainly consisting of Epstein-Barr virus-associated HLH) who underwent allo-HSCT using the registry database of the Japanese Society for Transplantation and Cellular Therapy, including 26 patients who underwent cord blood transplantation (CBT). One-fourth of patients received myeloablative conditioning (MAC), mainly consisting of total body irradiation-based regimens. The 3-year overall survival (OS) was 40.6%, while the 3-year cumulative incidences of relapse and non-relapse mortality (NRM) were 19.8% and 39.6%, respectively. In univariable analysis, age at allo-HSCT (the 3-year OS: 27.5% for ≥ 25 years old vs 58.0% for < 25 years old, P = .025), conditioning intensity (7.1% for MAC vs 51.8% for reduced-intensity conditioning (RIC), P = .002), and donor source (26.0% for CBT vs 52.9% for bone marrow or peripheral blood stem cell transplantation (BMT/PBSCT), P = .030) were associated with significantly inferior OS. In multivariable analysis, older age at allo-HSCT (≥ 25 years old) (Hazard ratio [HR], 2.37; 95% CI, 1.01 to 5.58; P = .048), MAC (HR, 2.45; 95% CI, 1.09 to 5.53; P = .031), and CBT (HR, 2.21; 95% CI, 1.04 to 4.71; P = .040) were independently associated with worse OS. In addition, only conditioning intensity predicted higher NRM (the 3-year NRM: 78.6% for MAC vs 26.6% for RIC), while no factors were associated with the relapse rate. This study includes the largest number of adult HLH patients undergoing CBT. Although the use of CBT is acceptable, BMT/PBSCT are more favorable strategies in allo-HSCT in adult HLH. Regarding conditioning intensity, RIC regimens are more beneficial in this setting.