Exagamglogene Autotemcel for Transfusion-Dependent ß-Thalassemia.

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis through ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of the erythroid-specific enhancer region of BCL11A in autologous CD34+ hematopoietic stem and progenitor cells (HSPCs). METHODS: We conducted an open-label, single-group, phase 3 study of exa-cel in patients 12 to 35 years of age with transfusion-dependent ß-thalassemia and a ß0/ß0, ß0/ß0-like, or non-ß0/ß0-like genotype. CD34+ HSPCs were edited by means of CRISPR-Cas9 with a guide mRNA. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was transfusion independence, defined as a weighted average hemoglobin level of 9 g per deciliter or higher without red-cell transfusion for at least 12 consecutive months. Total and fetal hemoglobin concentrations and safety were also assessed. RESULTS: A total of 52 patients with transfusion-dependent ß-thalassemia received exa-cel and were included in this prespecified interim analysis; the median follow-up was 20.4 months (range, 2.1 to 48.1). Neutrophils and platelets engrafted in each patient. Among the 35 patients with sufficient follow-up data for evaluation, transfusion independence occurred in 32 (91%; 95% confidence interval, 77 to 98; P<0.001 against the null hypothesis of a 50% response). During transfusion independence, the mean total hemoglobin level was 13.1 g per deciliter and the mean fetal hemoglobin level was 11.9 g per deciliter, and fetal hemoglobin had a pancellular distribution (≥94% of red cells). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No deaths or cancers occurred. CONCLUSIONS: Treatment with exa-cel, preceded by myeloablation, resulted in transfusion independence in 91% of patients with transfusion-dependent ß-thalassemia. (Supported by Vertex Pharmaceuticals and CRISPR Therapeutics; CLIMB THAL-111 ClinicalTrials.gov number, NCT03655678.).

Exagamglogene Autotemcel for Severe Sickle Cell Disease.

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis by means of ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of BCL11A. METHODS: We conducted a phase 3, single-group, open-label study of exa-cel in patients 12 to 35 years of age with sickle cell disease who had had at least two severe vaso-occlusive crises in each of the 2 years before screening. CD34+ HSPCs were edited with the use of CRISPR-Cas9. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was freedom from severe vaso-occlusive crises for at least 12 consecutive months. A key secondary end point was freedom from inpatient hospitalization for severe vaso-occlusive crises for at least 12 consecutive months. The safety of exa-cel was also assessed. RESULTS: A total of 44 patients received exa-cel, and the median follow-up was 19.3 months (range, 0.8 to 48.1). Neutrophils and platelets engrafted in each patient. Of the 30 patients who had sufficient follow-up to be evaluated, 29 (97%; 95% confidence interval [CI], 83 to 100) were free from vaso-occlusive crises for at least 12 consecutive months, and all 30 (100%; 95% CI, 88 to 100) were free from hospitalizations for vaso-occlusive crises for at least 12 consecutive months (P<0.001 for both comparisons against the null hypothesis of a 50% response). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No cancers occurred. CONCLUSIONS: Treatment with exa-cel eliminated vaso-occlusive crises in 97% of patients with sickle cell disease for a period of 12 months or more. (CLIMB SCD-121; ClinicalTrials.gov number, NCT03745287.).

Lentiviral Gene Therapy for Artemis-Deficient SCID.

BACKGROUND: The DNA-repair enzyme Artemis is essential for rearrangement of T- and B-cell receptors. Mutations in DCLRE1C, which encodes Artemis, cause Artemis-deficient severe combined immunodeficiency (ART-SCID), which is poorly responsive to allogeneic hematopoietic-cell transplantation. METHODS: We carried out a phase 1-2 clinical study of the transfusion of autologous CD34+ cells, transfected with a lentiviral vector containing DCLRE1C, in 10 infants with newly diagnosed ART-SCID. We followed them for a median of 31.2 months. RESULTS: Marrow harvest, busulfan conditioning, and lentiviral-transduced CD34+ cell infusion produced the expected grade 3 or 4 adverse events. All the procedures met prespecified criteria for feasibility at 42 days after infusion. Gene-marked T cells were detected at 6 to 16 weeks after infusion in all the patients. Five of 6 patients who were followed for at least 24 months had T-cell immune reconstitution at a median of 12 months. The diversity of T-cell receptor ß chains normalized by 6 to 12 months. Four patients who were followed for at least 24 months had sufficient B-cell numbers, IgM concentration, or IgM isohemagglutinin titers to permit discontinuation of IgG infusions. Three of these 4 patients had normal immunization responses, and the fourth has started immunizations. Vector insertion sites showed no evidence of clonal expansion. One patient who presented with cytomegalovirus infection received a second infusion of gene-corrected cells to achieve T-cell immunity sufficient for viral clearance. Autoimmune hemolytic anemia developed in 4 patients 4 to 11 months after infusion; this condition resolved after reconstitution of T-cell immunity. All 10 patients were healthy at the time of this report. CONCLUSIONS: Infusion of lentiviral gene-corrected autologous CD34+ cells, preceded by pharmacologically targeted low-exposure busulfan, in infants with newly diagnosed ART-SCID resulted in genetically corrected and functional T and B cells. (Funded by the California Institute for Regenerative Medicine and the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT03538899.).

Betibeglogene Autotemcel Gene Therapy for Non-ß0/ß0 Genotype ß-Thalassemia.

BACKGROUND: Betibeglogene autotemcel (beti-cel) gene therapy for transfusion-dependent ß-thalassemia contains autologous CD34+ hematopoietic stem cells and progenitor cells transduced with the BB305 lentiviral vector encoding the ß-globin (ßA-T87Q) gene. METHODS: In this open-label, phase 3 study, we evaluated the efficacy and safety of beti-cel in adult and pediatric patients with transfusion-dependent ß-thalassemia and a non-ß0/ß0 genotype. Patients underwent myeloablation with busulfan (with doses adjusted on the basis of pharmacokinetic analysis) and received beti-cel intravenously. The primary end point was transfusion independence (i.e., a weighted average hemoglobin level of ≥9 g per deciliter without red-cell transfusions for ≥12 months). RESULTS: A total of 23 patients were enrolled and received treatment, with a median follow-up of 29.5 months (range, 13.0 to 48.2). Transfusion independence occurred in 20 of 22 patients who could be evaluated (91%), including 6 of 7 patients (86%) who were younger than 12 years of age. The average hemoglobin level during transfusion independence was 11.7 g per deciliter (range, 9.5 to 12.8). Twelve months after beti-cel infusion, the median level of gene therapy-derived adult hemoglobin (HbA) with a T87Q amino acid substitution (HbAT87Q) was 8.7 g per deciliter (range, 5.2 to 10.6) in patients who had transfusion independence. The safety profile of beti-cel was consistent with that of busulfan-based myeloablation. Four patients had at least one adverse event that was considered by the investigators to be related or possibly related to beti-cel; all events were nonserious except for thrombocytopenia (in 1 patient). No cases of cancer were observed. CONCLUSIONS: Treatment with beti-cel resulted in a sustained HbAT87Q level and a total hemoglobin level that was high enough to enable transfusion independence in most patients with a non-ß0/ß0 genotype, including those younger than 12 years of age. (Funded by Bluebird Bio; HGB-207 ClinicalTrials.gov number, NCT02906202.).

Haematopoietic stem cell transplantation in children with sickle cell disease: Still to do?

Sickle cell disease affects the whole body through acute and chronic organ damage and results in significant physical and neurological constraints. The report by Cseh et al. demonstrates in a retrospective multinational study that allogeneic haematopoietic stem cell transplantation from HLA-identical siblings using a contemporary conditioning regimen is safe and effective in more than 96% of patients. Commentary on: Cseh et al. Busulfan-fludarabine- or treosulfan-fludarabine-based conditioning before allogeneic HSCT from matched sibling donors in paediatric patients with sickle cell disease: A study on behalf of the EBMT Paediatric Diseases and Inborn Errors Working Parties. Br J Haematol 2024;204:e1-e5. [Correction added on 23 November 2023, after first online publication: In the preceding sentence, the article title and doi have been updated in this version.].

Busulfan-fludarabine- or treosulfan-fludarabine-based conditioning before allogeneic HSCT from matched sibling donors in paediatric patients with sickle cell disease: A study on behalf of the EBMT Paediatric Diseases and Inborn Errors Working Parties.

How important is choice of conditioning regimen in allogeneic haematopoietic stem cell transplantation (HSCT) for sickle cell disease (SCD)? We compared HSCT outcomes by conditioning regimen in paediatric patients with SCD from the EBMT registry. In 2010-2020, 251 patients aged <18 years underwent a first matched sibling donor (MSD) HSCT with conditioning based on busulfan-fludarabine (bu-flu; n = 89) or treosulfan-fludarabine (treo-flu; n = 162). In the bu-flu and treo-flu groups, 51.7% and 99.4% of patients, respectively, received thiotepa. Median follow-up was 2.7 years. Two-year overall survival (OS) was 98.7% (95% confidence interval [CI]: 90.9-99.8) with bu-flu and 99.3% (95% CI: 95.2-99.9) with treo-flu (p = 0.63). Grade III-IV acute graft-versus-host disease (GVHD) at 100 days was 2.4% (95% CI: 0.4-7.5) and 0.6% (0.1%-3.2%) for bu-flu and treo-flu respectively (p = 0.25). The 2-year incidence of extensive chronic GVHD was 1.5% (95% CI: 0.1-7.3) with bu-flu and 8.0% (95% CI: 4.1-13.3) with treo-flu (p = 0.057). These multinational data confirm the excellent curative capacity of MSD HSCT with myeloablative conditioning. Both conditioning regimens yielded excellent OS, low rates of acute and chronic GVHD, and low rates of graft failure.

Busulfan, melphalan and carfilzomib high-dose chemotherapy and autologous haematopoietic stem cell transplantation in multiple myeloma.

The standard of care for fit, newly diagnosed multiple myeloma patients includes induction therapy followed by consolidative high-dose chemotherapy with melphalan and autologous stem cell transplant (AHSCT). Intensified preparative regimens, such as busulfan and melphalan (BuMel), have shown promise to lengthen progression-free survival (PFS). We previously reported that the addition of bortezomib to BuMel improved PFS compared to melphalan alone in CIBMTR-matched controls. We now integrate the second-generation protease inhibitor, carfilzomib, before and after BuMel (BuMelCar) in a phase I/II trial with carfilzomib. Patients with NDMM, relapsed/refractory MM (RRMM) and those failing prior AHSCT were eligible. Primary end-points were safety and tolerability. Secondary end-points included minimal residual disease negativity rates, PFS and OS. The study enrolled 19 patients. 73% were high risk either due to R-ISS III status, adverse genetics or relapsed after prior AHSCT. The maximum tolerated dose (MTD) of carfilzomib was determined to be 36 mg/m2. Noted grade 3 toxicities were febrile neutropenia (79%), mucositis (21%) and diarrhoea (16%). The 2-year PFS for the whole cohort and MTD was 89% and 100% respectively. 80% of all patients and 82% of patients in the MTD cohort achieved MRD negativity. Further studies regarding this regimen are planned.

Reduced-intensity conditioning with fludarabine/busulfan versus fludarabine/low-dose melphalan in patients with non-Hodgkin lymphoma undergoing allogeneic haematopoietic stem cell transplantation.

Reduced-intensity conditioning regimens are commonly used in allogeneic haematopoietic cell transplantation for non-Hodgkin lymphoma (NHL); however, the optimal regimen remains unknown. In this study, the outcomes of adult patients with NHL who received fludarabine plus reduced-dose busulfan (6.4 mg/kg; Flu/Bu2) (n = 286) and fludarabine plus low-dose melphalan (80 or 100 mg/m2; Flu/Mel80-100) (n = 283) between January 2009 and December 2020 were compared using Japanese registry data. The primary end-point was the 5-year overall survival (OS). The 5-year OS was 53.8% (95% CI, 47.6-59.6) and 42.4% (95% CI, 35.6-49.0) in the Flu/Bu2 and Flu/Mel80-100 groups respectively (p = 0.030). After inverse probability of treatment weighting adjustment, the adjusted HR of Flu/Bu2 compared with Flu/Mel80-100 group for 5-year OS was 0.77 (95% CI, 0.60-0.99, p = 0.046), 0.97 (95% CI, 0.78-1.21, p = 0.798) for 5-year progression-free survival, 0.65 (95% CI, 0.45-0.94, p = 0.022) for 5-year cumulative risk of non-relapse mortality and 1.25 (95% CI, 0.95-1.64, p = 0.115) for 5-year cumulative risk of relapse. In this study, patients with NHL who received Flu/Bu2 were associated with better OS and lower non-relapse mortality than those who received Flu/Mel80-100.

Successful Haematopoietic Stem Cell Transplantation for LRBA Deficiency with Fludarabine, Treosulfan, and Thiotepa-Based Conditioning.

LRBA deficiency is an inborn error of immunity defined by autoimmunity, lymphoproliferation, recurrent infections, cytopenia, and inflammatory bowel disease. Despite recent advances in managing this disease with targeted biologic therapy, haematopoietic stem cell transplant (HSCT) remains the only cure. However, great variability exists between protocols used to transplant patients with LRBA deficiency. We describe a cohort of seven patients with LRBA deficiency who underwent HSCT using a myeloablative, reduced toxicity regime of fludarabine, treosulfan, and thiotepa at two transplantation centres from 2016 to 2019. Data were collected both retrospectively and prospectively, measuring time to engraftment, infectious complications, incidence of graft versus host disease, and post-transplantation chimerism. Six of seven patients survived transplantation, and four of six surviving patients achieving treatment-free survival. We thus recommend that HSCT with fludarabine, treosulfan, and thiotepa-based conditioning be considered in patients with LRBA deficiency.

Impact of fludarabine and treosulfan on ovarian tumor cells and mesothelin chimeric antigen receptor T cells.

In addition to their immunosuppressive effect, cytostatics conditioning prior to adoptive therapy such as chimeric antigen receptor (CAR) T cells may play a role in debulking and remodeling the tumor microenvironment. We investigated in vitro the killing efficacy and impact of treosulfan and fludarabine on ovarian cancer cells expressing mesothelin (MSLN) and effect on MSLN-targeting CAR T cells. Treosulfan and fludarabine had a synergetic effect on killing of SKOV3 and OVCAR4 cells. Sensitivity to the combination of treosulfan and fludarabine was increased when SKOV3 cells expressed MSLN and when OVCAR4 cells were tested in hypoxia, while MSLN cells surface expression by SKOV3 and OVCAR4 cells was not altered after treosulfan or fludarabine exposure. Exposure to treosulfan or fludarabine (10 µM) neither impacted MSLN-CAR T cells degranulation, cytokines production upon challenge with MSLN + OVCAR3 cells, nor induced mitochondrial defects. Combination of treosulfan and fludarabine decreased MSLN-CAR T cells anti-tumor killing in normoxia but not hypoxia. In conclusion, treosulfan and fludarabine killed MSLN + ovarian cancer cells without altering MSLN-CAR T cells functions (at low cytostatics concentration) even in hypoxic conditions, and our data support the use of treosulfan and fludarabine as conditioning drugs prior to MSLN-CAR T cell therapy.

Outcome of first or second transplantation using unrelated umbilical cord blood without ATG conditioning regimen for pediatric bone marrow failure disorders.

BACKGROUND: Unrelated umbilical cord blood transplantation (UCBT) for bone marrow failure (BMF) disorders using conditioning regimens without Anti-Thymocyte Globulin (ATG) has been used as an alternative transplantation for emerging patients without matched-sibling donors. Experience with this transplant modality in children is limited, especially as a secondary treatment for transplant failure patients. PROCEDURE: We retrospectively reviewed 17 consecutive bone marrow failure patients who underwent unrelated umbilical cord blood transplantation in our center and received conditioning regimens of Total Body Irradiation (TBI) or Busulfan (BU) + Fludarabine (FLU) + Cyclophosphamide (CY). RESULTS: Among the 17 BMF patients, 15 patients were treated with first cord blood transplantation and another 2 with secondary cord blood transplantation because of graft failure after first haploidentical stem cell transplantation at days +38 and +82. All patients engrafted with a median donor cell chimerism of 50 % at days +7 (range, 16 %-99.95 %) and finally rose to 100 % at days +30. Median time to neutrophil engraftment was 19 days (range, 12-30) and time to platelet engraftment was 32 days (range, 18-61). Pre-engraftment syndrome (PES) was found in 16 patients (94.11 %, 16/17). Cumulative incidence of grades II to IV acute GVHD was 58.8 % (95 % CI: 32.7-84.9 %), and 17.6 % (95 % CI: 2.6-37.9 %) of patients developed chronic GVHD. The 3-year overall survival (OS) and failure-free survival (FFS) rates were 92.86 ± 6.88 %. CONCLUSION: UCBT is an effective alternative treatment for bone marrow failure pediatric patients. TBI/BU + FLU + CY regimen ensure a high engraftment rate for unrelated umbilical cord blood transplantation, which overcomes the difficulty of graft failure. Secondary salvage use of cord blood transplantation may still be useful for patients who have failed after other transplantation.

Hematopoietic stem cell transplantation for Wiskott-Aldrich syndrome: an EBMT Inborn Errors Working Party analysis.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for patients affected by Wiskott-Aldrich syndrome (WAS). Reported HSCT outcomes have improved over time with respect to overall survival, but some studies have identified older age and HSCT from alternative donors as risk factors predicting poorer outcome. We analyzed 197 patients undergoing transplant at European Society for Blood and Marrow Transplantation centers between 2006 and 2017 who received conditioning as recommended by the Inborn Errors Working Party (IEWP): either busulfan (n = 103) or treosulfan (n = 94) combined with fludarabine ± thiotepa. After a median follow-up post-HSCT of 44.9 months, 176 patients were alive, resulting in a 3-year overall survival of 88.7% and chronic graft-versus-host disease (GVHD)-free survival (events include death, graft failure, and severe chronic GVHD) of 81.7%. Overall survival and chronic GVHD-free survival were not significantly affected by conditioning regimen (busulfan- vs treosulfan-based), donor type (matched sibling donor/matched family donor vs matched unrelated donor/mismatched unrelated donor vs mismatched family donor), or period of HSCT (2006-2013 vs 2014-2017). Patients aged <5 years at HSCT had a significantly better overall survival. The overall cumulative incidences of grade III to IV acute GVHD and extensive/moderate/severe chronic GVHD were 6.6% and 2.1%, respectively. Patients receiving treosulfan-based conditioning had a higher incidence of graft failure and mixed donor chimerism and more frequently underwent secondary procedures (second HSCT, unconditioned stem cell boost, donor lymphocyte infusion, or splenectomy). In summary, HSCT for WAS with conditioning regimens currently recommended by IEWP results in excellent survival and low rates of GVHD, regardless of donor or stem cell source, but age ≥5 years remains a risk factor for overall survival.

Exosomes of mesenchymal stem cells and PRP restore spermatogenesis in the rat model of non-obstructive azoospermia.

In brief: Since available therapeutic approaches for chemotherapy-induced non-obstructive azoospermia (NOA) patients are not enough efficient, an urgent need for treatment alternatives is felt. This study shows that adipose tissue-derived mesenchymal stem cells-derived exosome (AD-Exo) treatment is more effective in ameliorating busulfan-induced NOA rat models compared to platelet-rich plasma (PRP). Abstract: Patients with non-obstructive azoospermia (NOA) are unable to have their children. Therefore, there is an urgent need for additional treatment alternatives for these patients. Recently, novel treatments based on the exosomes derived from mesenchymal stem cells (MSCs) as the agents responsible for exerting the paracrine effects and consequently biological functions of MSCs are proposed. Besides, platelet-rich plasma (PRP) as a significant blood byproduct has been therapeutically applied in several male infertility studies. In this study, we compared the effects of PRP and exosome treatment on spermatogenesis restoration in NOA rat models. Exosomes and PRP were isolated from the adipose tissue-derived MSCs (AD-MSCs) collected from conditioned medium and peripheral blood of human volunteers, respectively. Non-obstructive azoospermia (NOA) induction was done through two doses of busulfan at a 21-day interval. Thirty-five days after NOA induction, intratesticular injection of AD-MSCs-derived exosome (AD-Exo), PRP, and PBS was performed. The control group did not receive any treatment. Two months later, the rats were euthanized for further analysis. Our results revealed that both AD-Exo and PRP treatments improved the size and weight of testis, modulated the expression level of Dazl, Ddx4, Stra8, Pwil1, and Ccna1, and ameliorated the serum level of LDH, SOD, and GR enzymes in NOA rats. Moreover, the AD-Exo group showed improved testosterone, GPx, MAD, and CAT serum levels, sperm motility, and protein levels of DAZL and DDX4. This investigation verified the more efficient effects of AD-Exo treatment in comparison to PRP in ameliorating busulfan-induced NOA rat models.

Reduced intensity conditioning regimen of fludarabine, busulfan, ATG based haploidentical stem cell transplantation for older or unfit patients.

Reduced-intensity conditioning (RIC) regimens allogeneic hematopoietic stem cell transplantation (HSCT) was developed for older patients or those with poor functional status. Haploidentical donor was appropriate alternative donor for patients without matched donors or patients with emergency disease state. However, there was few studies report the outcomes of RIC regimen of anti-thymocyte globulin (ATG) based haploidentical HSCT. The selection of the appropriate RIC regimen based on age and comorbidities in ATG-based haploidentical HSCT remains poorly described. To investigate the safety and efficacy of RIC regimen ATG-based haploidentical HSCT in older or unfit patients. Additionally, to explore the potential factors that impact the prognosis of RIC regimen of ATG-based haploidentical HSCT. We included a retrospective cohort of 63 patients with hematologic malignant diseases who underwent their first RIC haploidentical HSCT from November 2016 to June 2022 at our institutions. The conditioning regimen involved fludarabine (Flu) 30 mg/m²/kg 6 days combined with busulfan 3.2 mg/kg 2 days (Bu2) or 3 days (Bu3). ATG-Fresenius (ATG-F) was administered 10 mg/kg in total, ATG-thymoglobulin (ATG-T) was administered 6 mg/kg in total. The median age of patients in the entire cohort was 60 (32-67) years with a median follow-up of 496 (83-2182) days. There were 29 patients with AML, 20 patients with MDS, and 14 patients with ALL. A total of 32 patients underwent Bu2 RIC haplo-HSCT and 31 patients were treated with Bu3 RIC haplo-HSCT. The 2-year overall survival (OS) and 2-year disease-free survival (DFS) in whole cohort were 67.7% (95% confidence interval [CI], 53.8 - 85.1%) and 61.4% (95% CI, 48.8 - 77.3%) respectively. The cumulative incidence rates of grades II to IV and grades III to IV acute graft-versus-host disease (aGVHD) in whole cohort were 15.8% (95% CI, 4.8 - 19.6%) and 9.7% (95% CI, 0.0 - 11.8%) respectively. The 2-year cumulative incidence of chronic GVHD was 34.0% (95% CI, 18.9 - 46.3%). The 2-year cumulative incidence rates of relapse (IR) and non-relapse mortality (NRM) rates in whole cohort were 27.5% (95% CI, 14.5 - 33.7%) and 11.6% (95% CI, 2.2 - 21.9%) respectively. The probability of 2-year OS were 60.2% (95% CI:42.5-85.3%) in Bu2 and 85.5%(95% CI:73.0-100%) in Bu3 group respectively(P = 0.150). The probability of 2-year DFS were 49.7% (95% CI:33.0-74.8%) in Bu2 and 72.6% (95% CI:55.5-95.5%) in Bu3 group respectively (P = 0.045). The 2-year IR of Bu2 group was significantly higher than Bu3 group (P = 0.045). However, the 2-year NRM were not significantly different between Bu2 and Bu3 group(P > 0.05). In multivariable analysis, RIC regimen of Bu3 had superior OS and DFS than Bu2 group respectively [HR 0.42, 95% CI 0.18-0.98; P = 0.044; HR 0.34, 95% CI 0.14-0.86; P = 0.022]. Besides, RIC regimen of Bu3 had lower IR than Bu2 group [HR 0.34, 95% CI 0.13-0.89; P = 0.029]. The RIC regimen of ATG-based haploidentical HSCT is a safe and effective treatment option for patients who are older or have poor functional status. In particular, a relatively high-intensity pre-treatment regimen consisting of Bu achieves significant improvements in OS and DFS, thus providing more favorable post-transplantation clinical outcomes.

Thiotepa-busulfan-fludarabine-based conditioning as a promising approach prior to allogeneic hematopoietic stem cell transplantation in patients with blastic plasmacytoid dendritic cell neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive myeloid malignancy associated with a poor prognosis. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) has emerged as a potential treatment strategy for BPDCN, standardized conditioning regimens remain lacking. In this manuscript, we present two cases of BPDCN that were treated with a thiotepa-busulfan-fludarabine (TBF)-based conditioning regimen prior to allo-HSCT. Both cases demonstrated complete remission post-transplantation, sustained donor chimerism, and remission maintenance, suggesting the potential efficacy of the TBF conditioning regimen for BPDCN transplantation. Given the small sample size in our study, we emphasize caution and advocate for larger studies to confirm the efficacy of TBF in the treatment of BPDCN.

Chidamide combined with a modified Bu-Cy conditioning regimen improves survival in patients with T-cell acute lymphoblastic leukemia/lymphoma undergoing allogeneic hematopoietic stem cell transplantation.

This study aimed to evaluate the efficacy and safety of chidamide (Chi) combined with a modified Busulfan-Cyclophosphamide (mBuCy) conditioning regimen for T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/LBL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Twenty-two patients received chidamide combined with mBuCy conditioning regimen (Chi group). A matched-pair control (CON) group of 44 patients (matched 1:2) received mBuCy only in the same period. The leukemia-free survival (LFS), overall survival (OS), cumulative incidence of relapse (CIR), and non-relapse-related mortality (NRM) were evaluated. Patients in the Chi group were associated with lower 2-year CIR (19.0 vs. 41.4%, P = 0.030), better 2-year LFS (76.1 vs. 48.1%, P = 0.014), and had no significant difference in 2-year OS (80.5 vs. 66.4%, P = 0.088). Patients with minimal residual disease (MRD) positive before HSCT in the Chi group exhibited an advantage in 2-year LFS and a trend towards better 2-year OS (75.0 vs. 10.2%, P = 0.048; 75.0 vs. 11.4%, P = 0.060, respectively). Multivariable analysis showed that the chidamide intensified regimen was independently associated with better LFS (HR 0.23; 95%CI, 0.08-0.63; P = 0.004), and showed no significant impact with OS for all patients (HR 0.34, 95%CI, 0.11-1.07; P = 0.064). The cumulative incidence rates of grade II-IV aGVHD were similar (36.4 vs. 38.6%, P = 0.858). 20 patients in Chi group evinced an elevation in γ-glutamyltransferase, as compared to the mBuCy group (90.9 vs. 65.9%, P = 0.029). No transplantation-related mortality was documented within the first 100 days after transplantation. The results demonstrate that the chidamide intensified regimen may be an effective and acceptable safety option for T-ALL/LBL undergoing allo-HSCT, and further validation is needed.

Addition of ruxolitinib and decitabine to modified busulfan/cyclophosphamide conditioning regimen for prophylaxis relapse in high-risk acute myeloid leukemia: the phase 2 prospective study.

The prognosis of patients with high-risk acute myeloid leukemia (AML) is dismal even after allogeneic stem cell transplantation (allo-HSCT), with relapse remaining the leading cause of treatment failure. Here, we investigated whether ruxolitinib and decitabine plus modified busulfan-cyclophosphamide (mBu/Cy) conditioning could reduce relapse in high-risk AML after allo-HSCT. This prospective, single-arm, phase II trial enrolled 37 patients who received allo-HSCT between September 2020 and March 2022 at the First Medical Center of Chinese People's Liberation Army (PLA) General Hospital. Eligible patients (10-62 years) had relapsed/refractory, positive measurable residual disease (MRD) prior to conditioning or adverse genetic abnormalities. Ruxolitinib (35 mg twice daily, days - 15 to - 10) and decitabine (20 mg/m2/day, days - 15 to - 10) were administered followed by mBu/Cy conditioning. All patients achieved engraftment. The cumulative incidences (CIs) of acute graft-versus-host disease (GVHD) grades II-IV and III-IV were 35.0% and 10.5%, respectively. The 1-year cumulative incidence of chronic GVHD was 8.1%. The 1-year CI of relapse was 29.7% among all patients, 0% in patients who achieved the first complete remission (CR1) prior to conditioning, and 0% in those with MRD-negative prior to conditioning. The 1-year non-relapse mortality was 5.4%. The 1-year probabilities of overall survival, disease-free survival, and GVHD-free relapse-free survival were 70.3%, 62.2%, and 54.1%, respectively. In conclusion, the novel conditioning showed primary efficacy in terms of a reduction in relapse in high-risk patients with AML after allo-HSCT, especially in those who achieved CR1 and MRD-negative prior to conditioning. Also, the new conditioning regimen may help reduce the incidence of chronic GVHD. ClinicalTrials.gov identifier: NCT04582604.

High dose total marrow irradiation (TMI) does not increase long-term toxicity of myeloablative fludarabine/busulfan (FluBu4) conditioning regimen in allogeneic hematopoietic stem cell transplantation (HSCT).

OBJECTIVES: Based on a previous phase 1 study, total marrow irradiation (TMI) at 9Gy was added to a myeloablative FluBu4 conditioning regimen in allogeneic hematopoietic stem cell transplantation (HSCT) for myeloid malignancies. Here, we report on the long-term toxicity of TMI combined with FluBu4 and compare it to patients who received only FluBu4. METHODS: We retrospectively analyzed 38 consecutive patients conditioned with FluBu4/TMI (n = 15) or FluBu4 (n = 23, control group) who had at least 1 year follow-up post-transplant. The rate of long-term adverse events that have been previously associated with total body irradiation (TBI) was analyzed in the two groups. RESULTS: The baseline characteristics did not differ between the two groups. The control group had a longer median follow-up (71.2 mo) than the TMI group (38.5 mo) (p = .004). The most common adverse events were xerostomia, dental complications, cataracts, or osteopenia and did not differ between the two groups. Cognitive dysfunction or noninfectious pneumonitis, often detected after high dose TBI, were also not different in the two groups (p = .12 and p = .7, respectively). There was no grade 4 adverse event. CONCLUSION: Our results suggest that a conditioning regimen with TMI 9Gy and FluBu4 does not increase long-term adverse events after allogeneic HSCT.

Impact of busulfan versus treosulfan dose intensity in myelofibrosis undergoing hematopoietic cell transplantation.

One key aspect of allogeneic hematopoietic cell transplantation (HCT) is pretransplant conditioning, balancing risk for relapse versus non-relapse mortality. Conditioning regimens with different alkylators at different doses can influence outcome, but data are missing for myelofibrosis, a challenging cohort of patients usually presenting at older age and with comorbidities. We evaluated in a multicenter retrospective study the comparative efficacy and safety of busulfan versus treosulfan in combination with fludarabine for myelofibrosis patients undergoing HCT. This study included 1115 patients (busulfan, n = 902; treosulfan, n = 213) receiving first HCT between 2005 and 2021. Patients were generally balanced for key patient characteristics. Overall survival at 4 years was 62% for the busulfan group versus 58% for the treosulfan group (p = .22). Impact on outcome was dose-dependent. Overall survival was 65% (95% CI, 61%-69%) for reduced intensity busulfan versus 69% (95% CI, 54%-84%) for reduced intensity treosulfan, 53% (95% CI, 44%-63%) for higher intensity busulfan, and 55% (95% CI, 46%-63%) for higher intensity treosulfan. Incidence of relapse was similar across intensity groups. In multivariable analysis, the hazard for death (with reduced intensity busulfan as reference) was 0.88 (95% CI, 0.39-2.01) for reduced intensity treosulfan (p = .77), 1.42 (95% CI, 0.96-2.10) for higher intensity busulfan (0.08), and 1.61 (95% CI, 1.14-2.26) for higher intensity treosulfan (p = .006). In terms of non-relapse mortality, comparison was not significantly different, while the hazard ratio for higher intensity treosulfan was 1.48 (95% CI, 0.98-2.23; p = .06). Here, we showed comparable outcomes and improved survival in myelofibrosis undergoing HCT with reduced intensity busulfan or treosulfan.

Safety and efficacy of a new high-dose regimen of panobinostat, gemcitabine, busulfan, and melphalan for 1st or 2nd salvage ASCT for refractory/relapsed or high-risk myeloma: Matched-pair comparisons with concurrent control cohorts.

Improvement of autologous stem-cell transplantation (ASCT) for myeloma is needed. Building on our prior work, we prospectively evaluated panobinostat and gemcitabine/busulfan/melphalan (GemBuMel) with ASCT in this population. Patients aged 18-65 years with relapsed/refractory or high-risk myeloma and adequate end-organ function were eligible. Treatment included panobinostat (20 mg/day, days -9 to -2) and GemBuMel (days -8 to -2). Patients were enrolled in 1st (ASCT-1) or 2nd ASCT (ASCT-2) cohorts. We compared their outcomes with all our other concurrent ASCT patients who met eligibility criteria but received melphalan or BuMel off study, matched for age, prior therapy lines, high-risk cytogenetics, and response at ASCT. We enrolled 80 patients, 48 and 32 in the ASCT-1 and ASCT-2 cohorts, respectively; in these two cohorts, high-risk cytogenetics were noted in 33 and 15 patients, respectively; unresponsive disease in 12 and 11 patients, respectively, after a median of 2 and 3 therapy lines, respectively. Transplant-related mortality (TRM) occurred in two ASCT-2 patients. One-year PFS rates were 69% (ASCT-1) and 72% (ASCT-2); 1-year OS rates were 79% (ASCT-1) and 84% (ASCT-2). Minimal residual disease negativity improved after ASCT-1 (8.5%-23%, p < .0001) and ASCT-2 (34%-55%, p = .02), which correlated with improved outcomes. Trial patients and controls (N = 371) had similar TRM and post-ASCT maintenance. Trial patients had better PFS after either a 1st (p = .02) or a 2nd ASCT (p = .04) than matched-paired control patients. In conclusion, panobinostat/GemBuMel is effective for relapsed/refractory or high-risk myeloma patients, with better PFS than concurrent matched controls receiving melphalan or BuMel.