Allogeneic HCT Research Articles

Contemporary Updates in the Prevention and Treatment of Graft-Versus-Host Disease.

Graft-versus-host disease (GVHD) is a serious complication after allogeneic HCT. Recently, several pivotal studies have been conducted demonstrating significant improvements in the management of GVHD. Here, we review important trials pertaining to GVHD prevention, acute GVHD treatment, and treatment of steroid refractory acute and chronic GVHD. Clinical trials in preventing GVHD demonstrate lower rates of severe acute GVHD and chronic GVHD with post-transplant cyclophosphamide. For acute GVHD, lower risk acute GVHD appears amenable to steroid-sparing therapies, such as sirolimus and itacitinib. Combinations with novel agents such as itolizumab appear promising for high risk acute GVHD. For steroid-refractory acute GVHD, ruxolitinib should be considered first line therapy. For chronic GVHD requiring therapy beyond steroids, ruxolitinib, belumosudil, and ibrutinib are now available and should be considered. Increasingly, GVHD has become a manageable complication after allogeneic HCT potentially translating to greater success with allogeneic HCT in the future.

VALIDATION OF THE REVISED 2022 EUROPEAN LEUKEMIANET RISK STRATIFICATION IN ADULT PATIENTS WITH ACUTE MYELOID LEUKEMIA

In 2022, the European LeukemiaNet (ELN) risk stratification for patients with AML has been updated. We aimed to validate the prognostic value of the 2022 ELN classification (ELN22) evaluating 1,570 newly diagnosed AML patients (median age, 56 years) treated with cytarabine-based intensive chemotherapy regimens. As compared to the 2017 ELN classification (ELN17), allocating 595 (38%), 413 (26%) and 562 (36%) patients to the favorable, intermediate and adverse risk category, ELN22 risk was favorable, intermediate, and adverse in 575 (37%), 410 (26%), and 585 (37%) patients, respectively. Risk group allocation was revised in 340 patients (22%). Most patients were re-classified into ELN22 intermediate or ELN22 adverse risk group. The allocation of patients according to the ELN22 risk categories resulted in a significantly distinct event-free survival (EFS), relapse-free survival (RFS), and overall survival (OS). As compared to ELN17, reallocation according to the ELN22 recommendations resulted in a significantly improved prognostic discrimination for OS (3-year area under the curve (AUC) 0.71 vs. 0.67). In patients with ELN22 favorable risk AML, co-occurring MR gene mutations did not significantly impact outcome. Within the ELN22 adverse risk group, we observed marked survival differences across mutational groups (5-year OS rate of 21% and 3% in patients with myelodysplasia-related (MR) gene mutations and TP53-mutated patients, respectively). In patients harboring MR gene mutations, EZH2-, STAG2- and ZRSR2-mutated patients showed an intermediate-like OS. In patients with secondary AML and those who underwent allogeneic HCT, EFS and OS significantly differed between ELN22 risk groups, while prognostic abilities of ELN17 and ELN22 classifications were similar. In conclusion, the ELN22 risk stratification improves prognostic discrimination in a large cohort of intensively treated AML patients. Given the heterogeneous outcome in patients with MR gene alterations, ranging between those of intermediate and adverse risk patients, we suggest reevaluation of risk allocation in these patients.

Precision medicine results from equitable representation.

In this special issue of Bone Marrow Transplantation, investigators report the impact of IDH1 [1], IDH2 [2], and FLT3-TKD [3] measurable residual disease (MRD) pre-hematopoietic cell transplantation (HCT) in predicting relapse of acute myeloid leukemia (AML) in adults receiving allogeneic HCT. The patient population for these retrospective cohorts, reflecting clinical transplant practice patterns and research biobank participation, was 84-86% non-Hispanic White (NHW) in each study. In this commentary, we explore the implications of racial and ethnic disparities in access to both HCT and HCT-related research and propose strategies to promote representation in precision medicine, given the emerging impact of the field on HCT outcomes.

Galectin-1 is associated with hematopoietic cell engraftment in murine MHC-mismatched allotransplantation.

Haploidentical hematopoietic cell transplantation (haplo-HCT) is associated with an increased risk of allograft rejection. Here, we employed a major histocompatibility complex (MHC)-mismatched allogeneic HCT (allo-HCT) murine model to better understand the role of Gal-1 in immune tolerance. Transplanted mice were classified into either rejected or engrafted based on donor chimerism levels. We noted significantly higher frequencies of CD4+ T cells, CD8+ T cells, natural killer cells, IFN-γ and TNF-α producing CD4+ T cells, and IFN-γ producing dendritic cells and macrophages in rejected mice. Conversely, we found significantly increased frequencies of regulatory T cells (Tregs), predominantly Helios+, IL-10-producing CD4+ T cells, type 1 regulatory (Tr1) cells, and the proportion of Tr1+Gal-1+ cells in engrafted mice. Further, Gal-1 specific blockade in Tregs reduced suppression of effector T cells in engrafted mice. Lastly, effector T cells from engrafted mice were more prone to undergo apoptosis. Collectively, we have shown that Gal-1 may favor HSC engraftment in an MHC-mismatched murine model. Our results demonstrate that Gal-1-expressing Tregs, especially at earlier time points post-transplant, are associated with inducing immune tolerance and stable mixed chimerism after HCT.

Comparison of Cytomegalovirus Reactivation in Children After Allogeneic Hematopoietic Cell Transplantation in 2 Transplant Eras

Reactivation of cytomegalovirus (CMV) is typically considered harmless as long as the immune system remains unaffected by medications or other factors. CMV reactivation may occur as a result of acute graft-versus-host disease of Grades II to IV. One possible factor contributing to this risk is the rise in the number of donors who lack genetic similarities or relationships. We hypothesized that the anti-CMV IgG level before transplantation could potentially serve as an indicator of the likelihood of CMV reactivation following hematopoietic cell transplantation. We examined a cohort of young individuals who underwent allogeneic HCT between 1998 and 2022 to evaluate the occurrence of CMV reactivation. The patients were divided into 2 time periods: 1998 to 2016 (comparison group) and 2017 to 2022 (intervention group). Between 1998 and 2016, 292 patients underwent hematopoietic HCT. Recipients from 2017 to 2022 experienced a slightly higher risk of CMV reactivation than those from 1998 to 2016. The comparison of prophylactic and preemptive medication showed no significant difference between the periods (P = .32). Patients treated from 1998 to 2016 experienced a 23% decrease in the risk of symptomatic CMV reactivation and related illnesses compared to those treated from 2017 to 2022 (P = .08 and .15, respectively). Our study showed that the intervention group had more symptomatic CMV reactivations. Various factors may contribute to this, including CD19-directed immunotherapy and the CMV status of the recipient before transplantation.

Reduced Intensity transplantation vs chemotherapy in CR1. A prospective, pseudorandomized study in 50-70 year old AML patients.

The aim of this prospective, international multicenter, pseudorandomized study comparing RICT HCT to standard-of-care chemotherapy in intermediate- or high-risk AML patients 50-70 years using the donor versus no-donor concept. Part 1 included only patients with potential family donors (RD) at the date of HLA-typing of the first potential sibling or CR-date, if later. Part 2 allowed the inclusion of patients without a possible sibling donor using the start of an unrelated donor (URD) search as inclusion date. 360 patients were registered and 309 analyzed. The median follow-up was 47 months (1-168). There was no difference in overall survival (OS) between the RD (n = 124) and the Control (n = 77) groups (p = 0.50, 3-year OS RD: 0.41(95% CI; 0.32-0.50); Controls: 0.49 (95% CI; 0.37-0.59)). The main cause of death was relapse (67% RD; 88% Controls). In Part 2, the 3-year OS was 0.60 (95% CI 0.50-0.70) for URD-HCT (n = 86) and 0.37 (95% CI 0.13-0.62) for Controls (n = 20), respectively (p = 0.10). When analyzing transplanted patients (Part 2), the OS at 3-years was higher for URD-HCT than RD-HCT (0.67 (0.55-0.76) vs. 0.42 (0.26-0.57; p = 0.005). This study doesn't support elderly HLA-identical siblings as donors for older AML patients undergoing a RICT allogeneic HCT in first CR.

Busulfan Exposure Target Attainment in Adults Undergoing Allogeneic Hematopoietic Cell Transplantation: A Single Day Versus a Multiple Day Therapeutic Drug Monitoring Regimen

Busulfan exposure has previously been linked to clinical outcomes, hence the need for therapeutic drug monitoring (TDM). Study objective was to evaluate the effect of day 1 TDM-guided dosing (regimen d1) versus days 1 + 2 TDM-guided dosing (regimen d1 + 2) on attaining adequate busulfan exposure. In this observational study, we included all adults who received an allogeneic HCT with intravenous once daily busulfan over 4 days as part of the conditioning regimen at the University Medical Centre Utrecht or between July 31, 2014 and November 12, 2021. The primary outcome was attainment of the therapeutic busulfan target (cumulative area under the curve [AUCcum] 80-100 mg*h/L). Dose adjustment was based on the estimated AUC of the preceding dosing day(s). Additional TDM was performed in the event of large dose adjustments (≥25%). The choice of TDM regimen was solely based on the first day the busulfan dose was administered (regimen d1 + 2 occurred when conditioning started on a Saturday). In all patients, blood sampling was performed on day 4 for evaluation. The AUCcum was estimated using a validated population pharmacokinetic model. Busulfan target exposure was compared between both TDM regimen groups using a propensity score adjusted logistic regression model. The variance in the AUCcum between the TDM regimens was compared using the F-test. Patients were stratified for age (categorical). In regimen d1, 87.6% (n = 113/129) attained a therapeutic busulfan exposure, while in regimen d1 + 2 a proportion of 97.4% was found (n = 74/76, adjusted odds ratio for non-therapeutic AUC = 0.19, 95% confidence interval [95% CI]: 0.04-0.89). Variance of busulfan exposure in the regimen d1 group (SD = 6.8 mg*h/L) differed significantly from the variance in the regimen d1 + 2 group (SD = 3.6 mg*h/L, F-test, P < .001). Performing busulfan TDM on both day 1 and day 2, rather than only on day 1, improves busulfan target exposure attainment in adults undergoing HCT, provided that subsequent TDM is carried out if required.

Sorafenib maintenance in FLT3-ITD mutated AML after allogeneic HCT: a real-world, single-center experience.

Despite allogeneic hematopoietic stem cell transplant (allo-HCT) and the development of novel FLT3 inhibitors in both induction (midostaurin) and in the relapsed/refractory setting (gilteritinib), FLT3-ITD mutated leukemia (FLT3-ITD+ AML) still represents a challenge for modern hematology. Sorafenib is, to this date, the only inhibitor that demonstrated efficacy in improving both progression-free and overall survival as post-HCT maintenance therapy, even if its use in this setting has not been approved so far by regulatory agencies. The aim of our study was to evaluate the feasibility, safety, and efficacy of sorafenib maintenance in preventing early relapse in FLT3-ITD+ AML after HCT in a single-center experience. We analyzed 26 consecutive patients who received post-HCT 2-year maintenance with sorafenib at our center between 2017 and 2023. The median time from HCT to sorafenib start was 130 days, and the median dosage was 200 mg per day. Two (8%) and three (12%) patients discontinued maintenance due to toxicity and disease relapse, respectively. Eight (31%) patients terminated the 2-year maintenance and stopped sorafenib, while 13 patients are still under treatment. Overall, 21/26 patients (81%) are alive and in stable complete remission as outlined by a 2-year disease-free survival of 83.61%. No major long-term toxicity was reported at the last follow-up. Our real-world experience supports the use of sorafenib as a feasible and effective therapeutic option in post-HCT maintenance for FLT3-ITD+ AML.

The effect of an online acceptance and commitment intervention on the meaning-making process in cancer patients following hematopoietic cell transplantation: study protocol for a randomized controlled trial enhanced with single-case experimental design

BackgroundHematopoietic cell transplantation (HCT) is a highly invasive and life-threatening treatment for hematological neoplasms and some types of cancer that can challenge the patient’s meaning structures. Restoring meaning (i.e., building more flexible and significant explanations of the disease and treatment burden) can be aided by strengthening psychological flexibility by means of an Acceptance and Commitment Therapy (ACT) intervention. Thus, this trial aims to examine the effect of the ACT intervention on the meaning-making process and the underlying mechanisms of change in patients following HCT compared to a minimally enhanced usual care (mEUC) control group. The trial will be enhanced with a single-case experimental design (SCED), where ACT interventions will be compared between individuals with various pre-intervention intervals.MethodsIn total, 192 patients who qualify for the first autologous or allogeneic HCT will be recruited for a two-armed parallel randomized controlled trial comparing an online self-help 14-day ACT training to education sessions (recommendations following HCT). In both conditions, participants will receive once a day a short survey and intervention proposal (about 5–10 min a day) in the outpatient period. Double-blinded assessment will be conducted at baseline, during the intervention, immediately, 1 month, and 3 months after the intervention. In addition, 6–9 participants will be invited to SCED and randomly assigned to pre-intervention measurement length (1–3 weeks) before completing ACT intervention, followed by 7-day observations at the 2nd and 3rd post-intervention measure. The primary outcome is meaning-related distress. Secondary outcomes include psychological flexibility, meaning-making coping, meanings made, and well-being as well as global and situational meaning.DiscussionThis trial represents the first study that integrates the ACT and meaning-making frameworks to reduce meaning-related distress, stimulate the meaning-making process, and enhance the well-being of HCT recipients. Testing of an intervention to address existential concerns unique to patients undergoing HCT will be reinforced by a statistically rigorous idiographic approach to see what works for whom and when. Since access to interventions in the HCT population is limited, the web-based ACT self-help program could potentially fill this gap.Trial registrationClinicalTrials.gov ID: NCT06266182. Registered on February 20, 2024.

Superiority of BM over PBSC for recipients with pre-transplant lung dysfunction in HLA-matched allogeneic HCT

Background aimsPre-transplant lung dysfunction is known to be a risk factor for non-relapse mortality (NRM) after allogeneic hematopoietic cell transplantation (allo-HCT). It is unclear which cell source gives better outcomes for patients with pulmonary dysfunction. MethodsWe analyzed 3289 adult patients with standard-risk disease who had received HLA-matched allo-HCT, and compared outcomes between those who received peripheral blood stem cell (PBSC) vs. bone marrow (BM) in two cohorts based on the presence of a lung score by the Hematopoietic Cell Transplantation-specific Comorbidity Index (HCT-CI): the Lung-scored (LS) and non-LS cohorts. ResultsIn the LS cohort, the 2-year overall survival (OS) in the BM group tended to be higher than that in the PBSC group (72.4% vs. 61.4%; P = 0.044). In the non-LS cohort, there was no significant difference between the two groups (71.7% vs. 73.2%; P = 0.13). Multivariate analyses confirmed that PBSC was significantly associated with inferior OS in the LS cohort (hazard ratio [HR], 1.66; 95% CI, 1.09-2.54; P = 0.019). On the other hand, the cell source did not affect OS in the non-LS cohort (HR, 0.92; 95% CI, 0.76-1.12; P = 0.41). We found that PBSC was associated with an increased risk of NRM in the LS cohort (HR, 2.17; 95% CI, 1.16-4.05; P = 0.016), while the cell source did not significantly affect NRM in the non-LS cohort. PBSC was not identified as a risk factor for relapse in either cohort. ConclusionsOur results suggest that BM might be beneficial for recipients with lung dysfunction in HLA-matched allo-HCT.

Post-Transplant Cyclophosphamide Attenuates the Adverse Effect of HLA Disparity and a Major ABO Mismatch on Graft Failure in Non-Myeloablative Allogeneic HCT

Post-Transplant Cyclophosphamide Attenuates the Adverse Effect of HLA Disparity and a Major ABO Mismatch on Graft Failure in Non-Myeloablative Allogeneic HCT

PMB-CT01 (BAFFR-CAR T cell) therapy to examine preliminary safety and clinical responses in patients with B-cell malignancies who are ineligible for or failed CD19-directed therapy, including CD19-negative disease.

6534 Background: CD19-targeted therapies have shown remarkable efficacy in patients with B-cell malignancies. However, relapse with CD19 loss as a mechanism of tumor escape is common and represents a serious challenge. Patients who are ineligible for or have failed prior CD19-directed therapy have limited salvage options and a very poor prognosis. The B-cell activating factor receptor (BAFF-R) is functionally expressed in B-cell acute lymphoblastic leukemia (B-ALL) and non-Hodgkin lymphomas (NHL), including in patients with CD19-negative relapse (Qin et al., Sci Transl Med. 2019). As a critical regulator of B-cell function and survival, BAFF-R may be less prone to downregulation by tumors as a mechanism of antigen escape. Methods: We are conducting two phase 1 clinical trials of BAFFR-CAR T cells in patients with relapsed/refractory (r/r) B-ALL (NCT04690595) and NHL (NCT05370430). Primary endpoints are dose limiting toxicities (DLTs) and all other toxicities. Secondary endpoints include response rate, minimal residual disease (MRD) negative rate, PFS and OS. Response is evaluated using European LeukemiaNet criteria for B-ALL and Lugano 2014 for NHL. Results: As of Feb. 1st, 2024, 1 B-ALL and 3 NHL patients have completed treatment and post-treatment evaluations. Each received 50M BAFFR CAR T cells (starting dose level in both trials). The B-ALL patient had CD19/CD20/CD22-negative disease, and had received prior blinatumomab. NHL patients #1 and #2 both had CD19-expressing mantle cell lymphoma (MCL) and had received prior CD19 CAR T cells. Patient #2 had also received a CD3/CD20 bispecific antibody. NHL patient #3 had CD19/CD20-negative T cell/histiocyte-rich large B-cell lymphoma (THRBCL) and had not received prior CD19 CAR T cells. There were no DLTs, all patients had Gr. 1 cytokine release syndrome, and 2/3 NHL patients had Gr. 1 immune effector cell-associated neurotoxicity syndrome. Robust CAR T cell expansion was seen in all patients with a peak on days 12-14 post-infusion. The B-ALL and the 2 MCL patients reached MRD-negative complete response (CR) at 1 month post-treatment. The THRBCL patient had partial response (PR) at 1 month that converted to CR at 3 months. The B-ALL patient successfully transitioned to allogeneic HCT while in CR at 3 months post-infusion. Responses are ongoing in all NHL patients at 14, 10, and 8 months for patients #1, #2 and #3, respectively. Additional patients have been enrolled at the next dose level (200M CAR T cells). Results for these patients will be presented at the meeting. Conclusions: With a 100% CR rate at 3 months in the first 4 patients and durable responses at dose level 1, BAFFR-CAR T cells are a promising therapeutic option for patients with r/r B-cell malignancies who are ineligible or failed prior CD19-targeted therapy, including with CD19 antigen loss. Clinical trial information: NCT04690595 , NCT05370430 .

Multiplexed Gastrointestinal PCR Panels for the Evaluation of Diarrhea in Hematopoietic Stem Cell Transplantation Recipients

Multiplexed gastrointestinal PCR panels (MGPPs) are frequently used to aid the diagnosis and management of diarrhea in hematopoietic stem cell transplantation (HCT) recipients. Many issues related to the optimal use of MGPPs in HCT patients remain to be clarified. We aimed to better define MGPP diagnostic and therapeutic stewardship in HCT recipients, including indications for and benefits of testing, optimal timing of tests, and interpretation of results. We retrieved 463 consecutive MGPPs ordered on 651 consecutive first HCT (312 allogeneic, 339 autologous) performed at our institution between June 2015 and June 2023. One hundred and sixteen of the 463 MGPPs (25%) identified at least 1 diarrheagenic pathogen, and 12 (3%) identified more than 1 diarrheagenic pathogen. A positive result was more likely if the test was ordered within 48 hours of a hospital admission (41%; 32 of 78) or as an outpatient (41%; 46 of 111) compared with evaluation of hospital-onset diarrhea (14%; 38 of 274). Among the positive results, the most frequent pathogens identified included Clostridioides difficile (64%), diarrheagenic Escherichia coli (20%), norovirus (9%), and adenovirus 40/41 (5%). Thirty-eight percent of the positive C. difficile MGPP determinations were associated with a positive test for toxin. In our allogeneic HCT cohort, 3% of MGPPs for hospital-onset diarrhea yielded an organism other than C. difficile. Fifty-six percent of positive and 14% of all submitted tests resulted in a change in treatment. For organisms other than C. difficile, only 1% of all tests and 5% of positive tests resulted in initiation of therapy. For patients at risk for acute graft-versus-host disease (aGVHD), a positive or negative MGPP result was not predictive of a new diagnosis of aGVHD in proximity to diarrhea onset. These results suggest that MGPP testing is most useful when performed at hospital admission or on an outpatient basis. Because MGPPs are sensitive and do not distinguish between colonization and causes of diarrhea, caution is needed when interpreting results, especially for toxin-negative C. difficile and diarrheagenic gram-negative organisms.

CURRENT USE AND OUTCOMES OF HEMATOPOIETIC STEM CELL TRANSPLANTATION: BRAZILIAN SUMMARY SLIDES – 2024

The development of the Brazilian Registry of Hematopoietic Cell Transplantation in collaboration with the Center for International Blood and Marrow Transplant Research (CIBMTR) allowed for an assessment of the activity and general outcomes of transplants in Brazil. Here, we report an updated activity. Brazilian transplant centers report their data to the CIBMTR, using the FormsNet3 platform. Information returns to Brazilian Cellular Therapy and Bone Marrow Transplant Society (SBTMO) through the Data Back to Centers (DBtC) tool. Data from patients who received an HCT from 2012 to 2023 from Brazilian centers were extracted from CIBMTR. Descriptive analysis was carried out by patient-, disease- and transplant-specific variables and overall survival analysis using Kaplan Meyer. A total of 12,230 patients were eligible for this study (5,573 autologous and 6,657 allogeneic transplants). The number of reporting centers increased from 40 to 44 during the period. The most common HCT indication in Brazil is AML for allogeneic HCT with 152 transplants year and multiple myeloma for autologous HCT with 245 transplants per year. Among allogeneic HCT, in the last 4 years, mismatched related donor was the main source of donors. Regarding the graft source for allogeneic transplants, BM was the most frequent among pediatric transplants, while PBSC was the most used in adults. Infections were the leading cause of death in the first 100 days after all types of transplants. Patients with acute leukemia who underwent HCT with advanced stage disease had lower survival rates compared to those at other stages. Despite the differences in the number of cases and follow-up time, the results in this study were similar to those presented in the United States (US) Summary Slides.

Increasing access to transplantation through telemedicine and patient navigation

BackgroundHematopoietic cell transplantation (HCT) is a promising treatment for hematological diseases, yet access barriers like cost and limited transplant centers persist. Telemedicine-based patient navigation (PN) has emerged as a solution. This study presents a cost-free PN telemedicine clinic (TC) in collaboration with the National Marrow Donor Program. Aim: to assess its feasibility and impac on HCT access determined by the cumulative incidence of transplantation. MethodsIn this single-center cohort study, patients of all ages and diagnoses referred for HCT participated. Two transplant physician-navigators established patient relationships via video calls, collecting medical history, offering HCT education and recommending pretransplant tests. The analysis involved descriptive statistics and intent-to-transplant survival assessment. ResultsOne hundred and three patients were included of whom n = 78 were referred for allogeneic HCT (alloHCT), with a median age of 28 years. The median time from initial contact to the first consult was 5 days. The cumulative incidence of transplantation was 50% at 6 months and 61% at 12 months, with varying outcomes based on HCT type. Notably, 49 patients were not transplanted, primarily due to refractory disease, progression or relapse (57.1%). Autologous HCT candidates and physician referrals were correlated with higher transplant success compared to alloHCT candidates and patients who were not referred by a physician. ConclusionOur pretransplant TC was feasible, facilitating access to HCT. Disease relapse posed a significant barrier. Enhancing timely physician referrals should be a focus for future efforts.

Management of post-autologous transplant relapse in patients with T-cell lymphomas.

Autologous hematopoietic cell transplantation (AHCT) is often used as a consolidation for patients with peripheral T-cell lymphomas (PTCLs) due to the poor prognosis associated with this heterogenous group of disorders. However, a significant number of patients will experience post-AHCT disease relapse. Here, we report a retrospective study of consecutive 124 patients with PTCLs who underwent AHCT from 2008 to 2020. With a median follow-up of 6.01 years following AHCT, 49 patients (40%) experienced disease relapse. As expected, more patients who were not in first complete remission experienced post-AHCT relapse. Following relapse, majority of the patients (70%) receiving systemic therapies intended as bridging to curative allogeneic HCT. However, only 18 (53%) patients eventually underwent allogeneic HCT. The estimated 3-year OS among patients proceeding to allogeneic HCT was 72% (95% CI 46%-87%). Our report details the pattern of post-AHCT relapse and the management of relapsed disease using different therapeutic modalities.

Outcomes of allogeneic haematopoietic cell transplantation for myelofibrosis in children and adolescents: the retrospective study of the EBMT Paediatric Diseases WP

This retrospective study evaluated 35 children (median age 5.2 years; range 0.4–18) with myelofibrosis (MF), including 33 with primary myelofibrosis and 2 with secondary myelofibrosis transplanted from matched sibling donor (MSD) (n = 17) or non-MSD (n = 18) between 2000 and 2022. Conditioning was usually chemotherapy-based (n = 33) and myeloablative (n = 32). Fifteen patients received bone marrow (BM), 14 haematopoietic cells (HC) from peripheral blood (PB), and 6 from cord blood (CB). Day +100 acute GvHD II–IV incidence was significantly lower after MSD-haematopoietic cell transplantation (MSD-HCT) than after non-MSD-HCT [18.8% (4.3–41.1) vs 58.8% (31–78.6); p = 0.01]. Six-year non-relapse mortality (NRM) was 18% (7.1–32.8), relapse incidence was 15.9% (5.6–30.9), progression-free survival (PFS) was 66.1% (47–79.7), GvHD-free relapse-free survival was 50% (30.6–66.7), and overall survival (OS) was 71.1% (51.4–84). Six-year PFS and OS were significantly higher after BM transplantation compared to HCT from other sources [85.1% (52.3–96.1) vs 50.8% (26.3–71), p = 0.03, and 90.9% (50.8–98.7) vs 54% (28.1–74.2), p = 0.01, respectively], whereas NRM was significantly lower [0% vs 32% (12.3–53.9); p = 0.02]. This first multicentre study on outcomes of allogeneic HCT in children with myelofibrosis proves feasibility and curative effect of transplantation in these children, suggests that bone marrow transplantation is associated with better outcomes, and indicates the need for further studies.

TIP24-196: Efficacy of a Mindfulness-Based Stress Management Program for Allogeneic HCT Caregivers: Trial in Progress.

TIP24-196: Efficacy of a Mindfulness-Based Stress Management Program for Allogeneic HCT Caregivers: Trial in Progress.

Significant impact of antibiotic exposure on GI-GVHD, NRM, and GRFS following allogeneic HCT with non-myeloablative Flu-TBI conditioning

Background Acute gastro-intestinal graft-versus-host disease (GI-GVHD) and non-relapse mortality (NRM) after allogeneic HCT are closely related to loss of microbial diversity and intestinal dominance by single taxa resulting from the use of antibiotics, dietary changes, and mucosal barrier injury. There is a paucity of data on the impact of use of antibiotics in HCT after Flu-TBI-based non-myeloablative (NMA) conditioning where there is absence of mucositis and limited malnutrition. Methods We did a retrospective single-center analysis of patients receiving Flu-TBI-based NMA HCT for a high-grade myeloid malignancy, mostly AML, and MDS, or acute lymphoblastic leukemia (ALL). We analyzed the impact of pre-engraftment antibiotic exposure, prophylactic ciprofloxacin, and or treatment with broad-spectrum cephalosporin/carbapenem, on HCT outcomes, with a focus on the incidence of acute GI-GVHD by day 180 and NRM at 1 year. Results A total of 150 patients were evaluable with a median age of 62 years. Antibiotics were used in 90 patients; 60 prophylactic use only and 30 therapeutic use with or without previous prophylaxis. Antibiotic use resulted in a significant higher incidence of GI-GVHD Stage 1–4; 29% (26/90) versus 5% (3/60) in those not receiving antibiotics (OR 8.1 (95% CI 2.3–28.3), p = 0.001). Use of antibiotics resulted in higher 1-year NRM (19% (17/90) versus 10% (6/60), HR 2.3, p = 0.06), and decreased 2-year GRFS (42% (38/90) versus 55% (33/60), HR 1.7, p = 0.04), but did not impact RFS or OS. Conclusions Use of antibiotics was related to the occurrence of GI-GVHD, NRM, and GRFS in patients receiving truly NMA HCT. Therefore, in the absence of mucositis and low incidence of bacteremia, antibiotics can and should be used restrictively in this setting.

Pulmonary function as a continuum of risk: critical care utilization and survival after allogeneic hematopoietic stem cell transplantation - a multicenter cohort study.

Abnormal pre-transplant pulmonary function tests (PFTs) are associated with reduced survival after allogeneic HCT. Existing scoring systems consider risk dichotomously, attributing risk only to those with abnormal lung function. In a multicenter cohort of 1717 allo-HCT recipients, we examined the association between pre-transplant PFT measures and need for ICU admission (120d), frequency of mechanical ventilation (120d) and overall survival (5 y). Predictive models were developed and validated using Cox proportional hazards, incorporating age, FEV1 (forced expiratory volume in 1-second) and diffusing capacity (DLCO). In univariate analysis, hazard ratios for each outcome (95% CI) were: mechanical ventilation (FEV1: 0.60 [0.52-0.69], DLCO: 0.69 [0.61-0.77], p < 0.001), ICU admission (FEV1: 0.74 [0.67-0.82], DLCO: 0.79 [0.72-0.86], p < 0.001) and overall survival (FEV1: HR 0.87 [0.81-0.94], DLCO: 0.83 [0.77-0.89], p < 0.001). A multivariable Cox model was developed and compared to the HCT-CI Pulmonary score in a validation cohort. This model was better at predicting need for ICU admission and mechanical ventilation, while both models predicted overall survival (p < 0.001). In conclusion, the risk conferred by pre-transplant pulmonary function should be considered in a continuous rather than dichotomous manner. A more granular prognostication system can better inform risk of critical care utilization in the early post-HCT period.