Pretransplant Conditioning Research Articles

Correction of osteopetrosis in the neonate oc/oc murine model after lentiviral vector gene therapy and non-genotoxic conditioning.

Autosomal recessive osteopetrosis (ARO) is a rare genetic disease, characterized by increased bone density due to defective osteoclast function. Most of the cases are due to TCIRG1 gene mutation, leading to severe bone phenotype and death in the first years of life. The standard therapy is the hematopoietic stem cell transplantation (HSCT), but its success is limited by several constraints. Conversely, gene therapy (GT) could minimize the immune-mediated complications of allogeneic HSCT and offer a prompt treatment to these patients. The Tcirg1-defective oc/oc mouse model displays a short lifespan and high bone density, closely mirroring the human condition. In this work, we exploited the oc/oc neonate mice to optimize the critical steps for a successful therapy. First, we showed that lentiviral vector GT can revert the osteopetrotic bone phenotype, allowing long-term survival and reducing extramedullary haematopoiesis. Then, we demonstrated that plerixafor-induced mobilization can further increase the high number of HSPCs circulating in peripheral blood, facilitating the collection of adequate numbers of cells for therapeutic purposes. Finally, pre-transplant non-genotoxic conditioning allowed the stable engraftment of HSPCs, albeit at lower level than conventional total body irradiation, and led to long-term survival and correction of bone phenotype, in the absence of acute toxicity. These results will pave the way to the implementation of an effective GT protocol, reducing the transplant-related complication risks in the very young and severely affected ARO patients.

Allogeneic Hematopoietic Cell Transplantation for Myelofibrosis Aged 70 Years or Older: A Study from the German Registry for Stem Cell Transplantation

Current consensus recommends hematopoietic cell transplantation (HCT) for patients with myelofibrosis with intermediate or high-risk disease and age of less than 70 years. However, a higher chronological age should not be prohibitive for the eligibility decision in general, acknowledging that current life expectancy for the general population aged 70 years is ∼15 years, and current numbers of patients transplanted at 70 years or older is steadily increasing. The following study aimed to evaluate characteristics and outcomes of HCT in 115 myelofibrosis patients aged 70 years or older. This is a retrospective multicenter study, using the German Registry for Stem Cell Transplantation and Cellular Therapy (DRST). Adult myelofibrosis patients were included who received HCT up until 2021. Patients with secondary leukemia were excluded. Main endpoints were HCT demographics over time and outcomes after HCT (including overall survival, relapse incidence, non-relapse mortality, and graft-versus-host disease/relapse-free survival). Numbers of HCT increased over the past decade, with a significant spike since 2019. Comorbidity status of transplanted patients improved over time, while reduced-intensity conditioning was the preferred HCT platform, especially in most recent years. The 3-year overall survival was 55% (95% confidence interval [CI], 44%-65%). The 1-year cumulative incidence of relapse was 7% (95% CI, 3%-13%) and the 1-year cumulative incidence of non-relapse mortality was 22% (95% CI, 14%-31%). The 3-year graft-versus-host disease and relapse-free survival was 37% (95% CI, 27%-47%). Driver mutation genotype (in particular, non-CALR/MPL genotype) appeared to be the only variable that was significantly and independently associated with better survival in multivariable analysis, whereas neither comorbidity index nor dose intensity of pre-transplant conditioning appeared to influence outcome. This study demonstrated feasibility of curative treatment with HCT for myelofibrosis aged 70 or older, with significant increases in HCT numbers and improved fitness of older adults over recent years.

Cisplatin as a Viable and Secure Alternative to Carmustine in BEAM-Based Conditioning for Autologous Hematopoietic Stem Cell Transplantation in Patients with Lymphoma

BackgroundHigh-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) is a standard treatment for relapsed/refractory lymphoma patients. Yet, the widespread use of BEAM is hindered by carmustine accessibility. This study evaluates the efficacy and safety of PEAM (Cisplatin, Etoposide, Cytarabine, and Melphalan) versus BEAM in auto-HSCT for Hodgkin (HL) and non-Hodgkin lymphoma (NHL) patients. MethodsWe conducted a retrospective single-center study of adult lymphoma patients who received PEAM or BEAM pretransplant conditioning between January 2004 to December 2022, comparing efficacy and safety outcomes. ResultsAmong 143 patients (median age of 33 years, 58% males), 55 had HL, and 88 had NHL. The overall response rate (ORR) was 86.7% for PEAM and 72.3% for BEAM, and the relapse rate (RR) was lower for PEAM than BEAM (22.9% vs 45.6%). Median time to relapse (TTR) and overall survival (OS) were not reached for either group. PEAM exhibited a shorter time to both neutrophil (NE) and platelet (PE) engraftment compared to BEAM (10 vs 12 days), with a more tolerable gastrointestinal (GI) toxicity profile. ConclusionsBoth BEAM and PEAM showed similar outcomes, demonstrating comparable efficacy in terms of ORR, TTR, and OS for both HL and NHL patients. However, PEAM-conditioning was associated with a shorter time to engraftment and fewer GI adverse events.

Patient-Reported Outcomes in Phase 3 Clinical Trials for Blood Cancers: A Systematic Review

Published research suggests that patient-reported outcomes (PROs) are neither commonly collected nor reported in randomized clinical trials (RCTs) for solid tumors. Little is known about these practices in RCTs for hematological malignant neoplasms. To evaluate the prevalence of PROs as prespecified end points in RCTs of hematological malignant neoplasms, and to assess reporting of PROs in associated trial publications. All issues of 8 journals known for publishing high-impact RCTs (NEJM, Lancet, Lancet Hematology, Lancet Oncology, Journal of Clinical Oncology, Blood, JAMA, and JAMA Oncology) between January 1, 2018, and December 13, 2022, were searched for primary publications of therapeutic phase 3 trials for adults with hematological malignant neoplasms. Studies that evaluated pretransplant conditioning regimens, graft-vs-host disease treatment, or radiotherapy as experimental treatment were excluded. Data regarding trial characteristics and PROs were extracted from manuscripts and trial protocols. Univariable analyses assessed associations between trial characteristics and PRO collection or reporting. Ninety RCTs were eligible for analysis. PROs were an end point in 66 (73%) trials: in 1 trial (1%) as a primary end point, in 50 (56%) as a secondary end point, and in 15 (17%) as an exploratory end point. PRO data were reported in 26 of 66 primary publications (39%): outcomes were unchanged in 18 and improved in 8, with none reporting worse PROs with experimental treatment. Trials sponsored by for-profit entities were more likely to include PROs as an end point (49 of 55 [89%] vs 17 of 35 [49%]; P < .001) but were not significantly more likely to report PRO data (20 of 49 [41%] vs 6 of 17 [35%]; P = .69). Compared with trials involving lymphoma (18 of 29 [62%]) or leukemia or myelodysplastic syndrome (18 of 28 [64%]), those involving plasma cell disorders or multiple myeloma (27 of 30 [90%]) or myeloproliferative neoplasms (3 of 3 [100%]) were more likely to include PROs as an end point (P = .03). Similarly, compared with trials involving lymphoma (3 of 18 [17%]) or leukemia or myelodysplastic syndrome (5 of 18 [28%]), those involving plasma cell disorders or multiple myeloma (16 of 27 [59%]) or myeloproliferative neoplasms (2 of 3 [67%]) were more likely to report PROs in the primary publication (P = .01). In this systematic review, almost 3 of every 4 therapeutic RCTs for blood cancers collected PRO data; however, only 1 RCT included PROs as a primary end point. Moreover, most did not report resulting PRO data in the primary publication and when reported, PROs were either better or unchanged, raising concern for publication bias. This analysis suggests a critical gap in dissemination of data on the lived experiences of patients enrolled in RCTs for hematological malignant neoplasms.

#1331 PCSK9 inhibitor addition during hypothermic perfusion protects kidney from ischemic damage in a rat model of donation after circulatory death

Abstract Background and Aims PCSK9 inhibitors (PCSK9i) are a new class of cholesterol-lowering drugs that is gaining market share in treating hypercholesterolemia because of their effectiveness in lowering LDL cholesterol and cardiovascular risk, even in patients with kidney disease. In addition to the well-known effect of inhibiting the LDL receptor catabolism, new pharmacological properties are being discovered. Experimental cellular and animal models have showed that PCSK9i reduce apoptosis, pyroptosis and in acute myocardial infarction decrease the infarct area, suggesting their protective role in tissue ischemia. However, so far PCSK9i effect on renal ischemic damage has not yet been studied. The aim of this study was to evaluate the effects of PEP 2-8 (PCSK9i) addition during hypothermic perfusion (HP) on ischemic kidney damage (ID) in a rat model of donation after circulatory death (DCD). Method n. 15 Sprague-Dawley rats were used as DCD donors. Briefly after a midline laparotomy, the left and right retroperitoneal renal areas were exposed, and lumbar arteries were isolated and sectioned; subsequently, the renal arteries and veins were isolated. After 30 min of warm ischemia, induced by aorta clamping, left and right nephrectomies were completed with preservation of the renal hilums. Then the kidneys were perfused with Perf-Gen Solution (100 ml) (Institut Georges Lopez, Lissieu, France) or Perf-Gen solution (100 ml) supplemented with 3ug (10ug/kg) of PEP 2-8. Continuous HP was performed for 6 h at 4 °C. DCD right and left kidneys of each rat were randomized to the following experimental groups: CTRL group: n = 15 DCD rat kidneys perfused with Perf-Gen PEP group: n = 15 DCD rat kidneys perfused with Pef-Gen supplemented with PEP 2-8. Effluent fluid was collected at the beginning (T0) and at the end (T6h) of HP. Glucose and potassium levels were measured in the effluent fluid at T0 and T6h. At T6h the kidneys were splitted into three aliquots; one was fixed in 10% formalin for morphological studies, and the other two were stored in trizol for gene expression studies and at −80 °C for biochemical assays respectively. Tubular ischemic damage (TID) was evaluated at T6 by scoring all tubules observed in at least 10 non-consecutive high-powered fields, as described by Paller (Paller Score). NOX- 4 gene expression was studied by RT-PCR assay. Tissue LDH and ATP levels were measured at T6h. Results PEP 2-8 treated kidneys showed a lower TID score compared to CTRL (PEP 107.0 IQR 90.75-116.0 vs CTRL 134.5 IQR 131.3-155.3 p &amp;lt; 0.005) (Fig. 1). The percentage of tubules with score zero (normal tubules) was higher in PEP than CTRL (PEP 29.0% range % 24.2-39.5 vs CTRL 9.5% range % 5.5-12.0, p &amp;lt; 0.001). The percentage of tubules with necrosis was lower in PEP than CTRL (PEP 5.5% range % 3.2-10.5 vs CTRL 12.5% range % 9.0-15.7, p &amp;lt; 0.005). Expression of NOX-4 gene, known inducer of apoptosis, was lower in PEP compared to CTRL (p &amp;lt; 0.05) Tissue ATP content was higher in PEP than CTRL (PEP 0.031 ± 0.01 vs CTRL 0.025 ± 0.006 p &amp;lt; 0.05). In tissue samples at T6 LDH was lower in PEP than CTRL (PEP 554.8 ± 164.7 vs CTRL 742.4 ± 256.7 p &amp;lt; 0.05) conversely the potassium release in effluent was significant only in CTRL (T6 vs T0 p &amp;lt; 0.01), according to TID score results. During HP, PEP 2-8 treated kidneys released more glucose in the effluent than CTRL kidneys (PEP 35.4 IQR 12.3-82.9 vs CTRL 12.3 IQR 7.1-70.5 p &amp;lt; 0.01). Conclusion Our preliminary results show that PEP 2-8 added to Perf-Gen solution during HP protects kidneys from ID, preserving energy metabolism in rat DCD model. To the best of our knowledge, this is the first evidence of protective role of PCSK9 inhibition in pre-transplant renal conditioning and potentially it could be used in conditioning other organs (liver, lung). However, further studies are necessary to understand the mechanisms underlying PCSK9i effect on energy metabolism and neoglucogenesis.

#1446 PCSK9 inhibitor addition during hypothermic perfusion protects kidney from ischemic damage in a rat model of donation after circulatory death

Abstract Background and Aims PCSK9 inhibitors (PCSK9i) are a new class of cholesterol-lowering drugs that is gaining market share in treating hypercholesterolemia because of their effectiveness in lowering LDL cholesterol and cardiovascular risk, even in patients with kidney disease. In addition to the well-known effect of inhibiting the LDL receptor catabolism, new pharmacological properties are being discovered. Experimental cellular and animal models have showed that PCSK9i reduce apoptosis, pyroptosis and in acute myocardial infarction decrease the infarct area, suggesting their protective role in tissue ischemia. However, so far PCSK9i effect on renal ischemic damage has not yet been studied. The aim of this study was to evaluate the effects of PEP 2-8(PCSK9i) addition during hypothermic perfusion (HP) on ischemic kidney damage (ID) in a rat model of donation after circulatory death (DCD). Method n. 15 Sprague-Dawley rats were used as DCD donors. Briefly after a midline laparotomy, the left and right retroperitoneal renal areas were exposed, and lumbar arteries were isolated and sectioned; subsequently, the renal arteries and veins were isolated. After 30 min of warm ischemia, induced by aorta clamping, left and right nephrectomies were completed with preservation of the renal hilums. Then the kidneys were perfused with Perf-Gen Solution (100 ml) (Institut Georges Lopez, Lissieu, France) or Perf-Gen solution (100 ml) supplemented with 3ug (10ug/kg) of PEP 2-8. Continuous HP was performed for 6 h at 4 °C. DCD right and left kidneys of each rat were randomized to the following experimental groups: CTRL group: n = 15 DCD rat kidneys perfused with Perf-Gen PEP group: n = 15 DCD rat kidneys perfused with Pef-Gen supplemented with PEP 2-8. Effluent fluid was collected at the beginning (T0) and at the end (T6h) of HP. Glucose and potassium levels were measured in the effluent fluid at T0 and T6h. At T6h the kidneys were splitted into three aliquots; one was fixed in 10% formalin for morphological studies, and the other two were stored in trizol for gene expression studies and at −80 °C for biochemical assays respectively. Tubular ischemic damage (TID) was evaluated at T6 by scoring all tubules observed in at least 10 non-consecutive high-powered fields, as described by Paller (Paller Score). NOX- 4 gene expression was studied by RT-PCR assay. Tissue LDH and ATP levels were measured at T6h. Results PEP 2-8 treated kidneys showed a lower TID score compared to CTRL (PEP 107.0 IQR 90.75-116.0 vs CTRL 134.5 IQR 131.3-155.3 p &amp;lt; 0.005) (Fig. 1). The percentage of tubules with score zero (normal tubules) was higher in PEP than CTRL (PEP 29.0% range % 24.2-39.5 vs CTRL 9.5% range % 5.5-12.0, p &amp;lt; 0.001). The percentage of tubules with necrosis was lower in PEP than CTRL (PEP 5.5% range % 3.2-10.5 vs CTRL 12.5% range % 9.0-15.7, p &amp;lt; 0.005). Expression of NOX-4 gene, known inducer of apoptosis, was lower in PEP compared to CTRL (p &amp;lt; 0.05) Tissue ATP content was higher in PEP than CTRL (PEP 0.031 ± 0.01 vs CTRL 0.025 ± 0.006 p &amp;lt; 0.05). In tissue samples at T6 LDH was lower in PEP than CTRL (PEP 554.8 ± 164.7 vs CTRL 742.4 ± 256.7 p &amp;lt; 0.05) conversely the potassium release in effluent was significant only in CTRL (T6 vs T0 p &amp;lt; 0.01), according to TID score results. During HP, PEP 2-8 treated kidneys released more glucose in the effluent than CTRL kidneys (PEP 35.4 IQR 12.3-82.9 vs CTRL 12.3 IQR 7.1-70.5 p &amp;lt; 0.01). Conclusion Our preliminary results show that PEP 2-8 added to Perf-Gen solution during HP protects kidneys from ID, preserving energy metabolism in rat DCD model. To the best of our knowledge, this is the first evidence of protective role of PCSK9 inhibition in pre-transplant renal conditioning and potentially it could be used in conditioning other organs (liver, lung). However, further studies are necessary to understand the mechanisms underlying PCSK9i effect on energy metabolism and neoglucogenesis.

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.

Retrospective clinical study on cryopreservation-free integrated autologous hematopoietic stem cell transplantation model for newly diagnosed multiple myeloma

Objective: To explore the efficacy and safety of cryopreservation-free integrated autologous hematopoietic stem cell transplantation (HSCT) model for patients with multiple myeloma. Methods: A total of 96 patients with newly diagnosed multiple myeloma (NDMM) between July 31, 2020, and December 31, 2022, were retrospectively analyzed, of which 41 patients in the observation group received integrated non-cryopreserved transplantation mode. After hematopoietic stem cells were mobilized and collected, melphalan was started immediately for pre-transplant conditioning, and non-cryopreserved grafts from the medical blood transfusion refrigerator were directly injected intravenously into the patient within 24-48 h after the melphalan conditioning. The control group consisted of 55 patients who received traditional transplantation mode. After hematopoietic stem cells were collected, stem cell cryopreservation was performed in liquid nitrogen, and then the transplant plans were started at the right time. All patients received mobilization of autologous hematopoietic stem cells using the G-CSF combined with the plerixafor. Results: ① A total of 34 patients (82.9% ) with VGPR plus CR in the observation group were significantly higher than 33 patients (60.0% ) in the control group (P=0.016). ②Compared with the control group, the incidence of grade 1 oral mucosal inflammation was higher in the observation group (P<0.001) ; however, the incidence of grades 2 and 3 oral mucosal inflammation was lower (P=0.004, P=0.048), and neither group experienced grade 4 or above oral mucosal inflammation. The incidence of grade 1 diarrhea was higher in the observation group (P=0.002), whereas the incidence of grade 3 diarrhea was lower (P=0.007). No statistically significant difference was observed in the incidence of grade 4 diarrhea (P=0.506), and neither group experienced grade 5 diarrhea. ③ The incidence of bacterial infection in the observation group was lower than that in the control group (34.1% vs 65.5%, P=0.002), whereas no statistically significant difference was observed in the incidence of fungal infection (29.3% vs 31.4%, P=0.863) and viral infection (4.88% vs 3.64%, P=0.831). ④No statistically significant difference was observed in the implantation time of granulocytes and platelets between the observation and control groups [10 (8-20) days vs 11 (8-17) days, P=0.501; 13 (10-21) days vs 15 (10-20) days, P=0.245]. ⑤ All patients did not receive lenalidomide treatment 100 days post-transplantation. At 30 days post-transplantation, the CTL, NK, and Th cell counts in the observation group were lower than those in the control group (P<0.001, P=0.002, P=0.049), and the NKT cell counts were higher than those in the control group (P=0.024). At 100 days post-transplantation, the CTL, NKT, and Th cell counts in the observation group were higher than those in the control group (P=0.025, P=0.011, P=0.007), and no statistically significant difference in NK cell counts was observed between the two groups (P=0.396). ⑥ The median follow-up was 18 (4-33) months. The overall 2-year survival rates of the observation and control groups post-transplantation were 91.5% and 78.2%, respectively (P=0.337). The recurrence-free survival rates were 85.3% and 77.6%, respectively (P=0.386), and the cumulative recurrence rates were 9.8% and 16.9%, respectively (P=0.373) . Conclusion: In NDMM, the cryopreservation-free integrated autologous HSCT model can achieve similar therapeutic effects as traditional transplantation models, with lower rates of severe mucosal inflammation and infection compared with traditional transplantation models.

Survival after allogeneic transplantation according to pretransplant minimal residual disease and conditioning intensity in patients with acute myeloid leukemia.

The measurement of minimal residual disease (MRD) by multiparametric flow cytometry (MFC) before hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) is a powerful prognostic factor. The interaction of pretransplant MRD and the conditioning intensity has not yet been clarified. The aim of this study is to analyze the transplant outcomes of patients with AML who underwent HSCT in complete remission (CR), comparing patients with positive MRD (MRD+) and negative MRD (MRD-) before HSCT, and the interaction between conditioning intensity and pre-HSCT MRD. We retrospectively analyzed the transplant outcomes of 118 patients with AML who underwent HSCT in CR in a single institution, comparing patients with MRD+ and MRD- before HSCT using a cutoff of 0.1% on MFC, and the interaction between conditioning intensity and pre-HSCT MRD. Patients with MRD+ before HSCT had a significantly worse 2-year (2y) event-free survival (EFS) (56.5% vs. 32.0%, p = 0.018) than MRD- patients, due to a higher cumulative incidence of relapse (CIR) at 2 years (49.0% vs. 18.0%, p = 0.002), with no differences in transplant-related mortality (TRM) (2y-TRM, 19.0% and 25.0%, respectively, p = 0.588). In the analysis stratified by conditioning intensity, in patients who received MAC, those with MRD- before HSCT had better EFS (p = 0.009) and overall survival (OS) (p = 0.070) due to lower CIR (p = 0.004) than MRD+ patients. On the other hand, the survival was similar in reduced intensity conditioning (RIC) patients regardless of the MRD status. Patients with MRD+ before HSCT have worse outcomes than MRD- patients. In patients who received MAC, MRD- patients have better EFS and OS due to lower CIR than MRD+ patients, probably because they represent a more chemo-sensitive group. However, among RIC patients, results were similar regardless of the MRD status.

High sensitivity of host Helios+/Neuropilin-1+ Treg to pretransplant conditioning hampers development of OX40bright/integrin-β7+ regulatory cells in acute gastrointestinal GvHD.

This study sought to compare the behavior of Treg subsets displaying different coexpression patterns of Neuropilin-1 (Nrp1) and Helios, under the influence of gut stress unrelated to hematopoietic stem cell transplantation, pretransplantation conditioning, and posttransplant gastrointestinal acute graft versus host disease (GI-aGvHD). Host CD4+/CD25hi/Foxp3+ Treg cells, identified by flow cytometry, were isolated from various tissues of mice affected by these stressors. Expression of CD25, CTLA-4, CD39, OX40, integrin-β7, LAG3, TGFβ/LAP, granzyme-A, -B, and interleukin-10 was compared in four Treg subsets displaying Helios or Nrp1 only, both or none. Fluorescence-activated cell sorter-sorted Treg subsets, displaying markers affected in a conditioning- and GI-aGVHD-restricted manner, were further investigated by transcriptome profiling and T-cell suppression assays. We found that conditioning by irradiation greatly diminished the relative frequency of Helios+/Nrp1+ Treg, shifting the balance toward Helios-/Nrp1- Treg in the host. Upregulation of integrin-β7 and OX40 occurred in GI-aGvHD-dependent manner in Helios+/Nrp1+ cells but not in Helios-/Nrp1- Treg. Sorted Treg subsets, confirmed to overexpress Nrp1, Helios, OX40, or integrin-β7, displayed superior immunosuppressive activity and enrichment in activation-related messenger RNA transcripts. Our data suggest that conditioning-induced shrinkage of the Nrp1+/Helios+ Treg subset may contribute to the development of GI-GvHD by impairing gut homing and decreasing the efficiency of Treg-mediated immunosuppression.

Innovations in conditioning and post-transplant maintenance in AML: genomically informed revelations on the graft-versus-leukemia effect.

Acute Myeloid Leukemia (AML) is the prototype of cancer genomics as it was the first published cancer genome. Large-scale next generation/massively parallel sequencing efforts have identified recurrent alterations that inform prognosis and have guided the development of targeted therapies. Despite changes in the frontline and relapsed standard of care stemming from the success of small molecules targeting FLT3, IDH1/2, and apoptotic pathways, allogeneic stem cell transplantation (alloHSCT) and the resulting graft-versus-leukemia (GVL) effect remains the only curative path for most patients. Advances in conditioning regimens, graft-vs-host disease prophylaxis, anti-infective agents, and supportive care have made this modality feasible, reducing transplant related mortality even among patients with advanced age or medical comorbidities. As such, relapse has emerged now as the most common cause of transplant failure. Relapse may occur after alloHSCT because residual disease clones persist after transplant, and develop immune escape from GVL, or such clones may proliferate rapidly early after alloHSCT, and outpace donor immune reconstitution, leading to relapse before any GVL effect could set in. To address this issue, genomically informed therapies are increasingly being incorporated into pre-transplant conditioning, or as post-transplant maintenance or pre-emptive therapy in the setting of mixed/falling donor chimerism or persistent detectable measurable residual disease (MRD). There is an urgent need to better understand how these emerging therapies modulate the two sides of the GVHD vs. GVL coin: 1) how molecularly or immunologically targeted therapies affect engraftment, GVHD potential, and function of the donor graft and 2) how these therapies affect the immunogenicity and sensitivity of leukemic clones to the GVL effect. By maximizing the synergistic action of molecularly targeted agents, immunomodulating agents, conventional chemotherapy, and the GVL effect, there is hope for improving outcomes for patients with this often-devastating disease.

Cardiovascular Management of Patients Undergoing Hematopoietic Stem Cell Transplantation: From Pretransplantation to Survivorship: A Scientific Statement From the American Heart Association.

Hematopoietic stem cell transplantation can cure various disorders but poses cardiovascular risks, especially for elderly patients and those with cardiovascular diseases. Cardiovascular evaluations are crucial in pretransplantation assessments, but guidelines are lacking. This American Heart Association scientific statement summarizes the data on transplantation-related complications and provides guidance for the cardiovascular management throughout transplantation. Hematopoietic stem cell transplantation consists of 4 phases: pretransplantation workup, conditioning therapy and infusion, immediate posttransplantation period, and long-term survivorship. Complications can occur during each phase, with long-term survivors facing increased risks for late effects such as cardiovascular disease, secondary malignancies, and endocrinopathies. In adults, arrhythmias such as atrial fibrillation and flutter are the most frequent acute cardiovascular complication. Acute heart failure has an incidence ranging from 0.4% to 2.2%. In pediatric patients, left ventricular systolic dysfunction and pericardial effusion are the most common cardiovascular complications. Factors influencing the incidence and risk of complications include pretransplantation therapies, transplantation type (autologous versus allogeneic), conditioning regimen, comorbid conditions, and patient age. The pretransplantation cardiovascular evaluation consists of 4 steps: (1) initial risk stratification, (2) exclusion of high-risk cardiovascular disease, (3) assessment of cardiac reserve, and (4) optimization of cardiovascular reserve. Clinical risk scores could be useful tools for the risk stratification of adult patients. Long-term cardiovascular management of hematopoietic stem cell transplantation survivors includes optimizing risk factors, monitoring, and maintaining a low threshold for evaluating cardiovascular causes of symptoms. Future research should prioritize refining risk stratification and creating evidence-based guidelines and strategies to optimize outcomes in this growing patient population.

Maintain Efficacy and Spare Toxicity: Traditional and New Radiation-Based Conditioning Regimens in Hematopoietic Stem Cell Transplantation.

Novelty in total body irradiation (TBI) as part of pre-transplant conditioning regimens lacked until recently, despite the developments in the field of allogeneic stem cell transplants. Long-term toxicities have been one of the major concerns associated with TBI in this setting, although the impact of TBI is not so easy to discriminate from that of chemotherapy, especially in the adult population. More recently, lower-intensity TBI and different approaches to irradiation (namely, total marrow irradiation, TMI, and total marrow and lymphoid irradiation, TMLI) were implemented to keep the benefits of irradiation and limit potential harm. TMI/TMLI is an alternative to TBI that delivers more selective irradiation, with healthy tissues being better spared and the control of the radiation dose delivery. In this review, we discussed the potential radiation-associated long-term toxicities and their management, summarized the evidence regarding the current indications of traditional TBI, and focused on the technological advances in radiotherapy that have resulted in the development of TMLI. Finally, considering the most recent published trials, we postulate how the role of radiotherapy in the setting of allografting might change in the future.

Procalcitonin elevation in febrile recipients during pre-transplant conditioning with anti-thymocyte globulin

Procalcitonin elevation in febrile recipients during pre-transplant conditioning with anti-thymocyte globulin

Impact of Anti-Thymocyte Globulin on Procalcitonin Levels Comparison during Fever in Allogeneic Stem Cell Transplantation Conditioning

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a complex medical procedure that offers hope for patients with various hematological disorders. However, one of the significant challenges associated with allo-HSCT is the risk of infection, which remains a major contributor to non-relapse mortality. Detecting and managing infectious diseases in febrile patients during the pre-transplant conditioning phase is of utmost importance to ensure successful transplantation outcomes. In this context, procalcitonin (PCT) has emerged as a valuable diagnostic tool, serving as an auxiliary marker for severe infections. Additionally, PCT has shown promise as a predictor of infections in patients undergoing allo-HSCT. Its ability to aid in early detection and subsequent intervention has made it an attractive biomarker for clinicians. However, the interpretation of PCT levels in patients receiving anti-thymocyte globulin (ATG) as part of their pre-transplant conditioning has posed specific challenges. ATG, a commonly used immunosuppressive agent in allo-HSCT, plays a vital role in reducing the risk of graft rejection and graft-versus-host disease. However, ATG administration is not without its drawbacks, as it can lead to various side effects such as fever and hypotension. These ATG-induced symptoms must be carefully distinguished from infectious diseases to ensure appropriate treatment decisions. One particular concern in this regard is the potential impact of ATG administration on PCT levels. Unfortunately, there is a paucity of data on PCT levels in febrile patients who have received ATG, making it difficult for clinicians to interpret the results accurately. Furthermore, a comprehensive analysis comparing the increase in PCT levels during the conditioning phase for allo-HSCT and its associated risk factors in ATG and non-ATG regimens is lacking. Understanding how ATG affects PCT levels during febrile episodes and whether PCT can effectively discriminate between infections and ATG-related symptoms is crucial for optimizing patient care. To address these gaps in knowledge, we conducted a retrospective analysis involving 76 patients who developed febrile episodes during the pre-transplant conditioning phase, and their PCT levels were measured and compared in our institution. Our study aimed to elucidate whether ATG administration could lead to increased PCT levels during febrile episodes in the context of pre-transplant conditioning and whether PCT could serve as a reliable marker for distinguishing infections during this critical period. The findings of our analysis shed light on the complex relationship between ATG administration, PCT levels, and infectious diseases. Notably, ATG administration was identified as the sole significant factor contributing to increased PCT positivity during fever (p = 0.01). In contrast, the presence of infectious diseases did not significantly impact PCT positivity in the ATG group (p = 0.24). Intriguingly, bloodstream infection emerged as a significant risk factor for PCT positivity in patients who received non-ATG regimens (p &amp;lt; 0.01). These results underscore the importance of considering ATG administration when interpreting PCT levels in febrile patients undergoing pre-transplant conditioning for allo-HSCT. The administration of ATG can confound the interpretation of PCT levels during febrile episodes, potentially leading to inaccurate diagnoses of infectious diseases. Clinicians must exercise caution and be aware of this confounding factor when incorporating PCT values into the diagnostic workup, particularly in patients receiving ATG regimens. In conclusion, our study highlights the complexity of using PCT as a diagnostic marker in febrile patients undergoing pre-transplant conditioning for allo-HSCT. While PCT shows promise as a valuable tool for predicting and detecting infections, its interpretation must be approached with caution in patients receiving ATG regimens. Future research is warranted to further elucidate the intricacies of PCT dynamics in the context of allo-HSCT, enabling clinicians to optimize its use and improve patient outcomes in this challenging and high-stakes medical procedure.

Extracellular Release of Damaged Mitochondria Induced By Cytotoxic Conditioning Exacerbates Graft-Versus-Host Disease

Despite therapeutic advancements, graft versus host disease (GVHD) is a major complication of hematopoietic stem cell transplantation (HSCT). Pathogen and damage associated molecular patterns released following pre-transplant conditioning have an important role in the initiation of GVHD. However, the role of extracellular mitochondria (exMito) as an endogenous danger signal has not been explored. Herein, we report that cytotoxic conditioning with radiation leads to mitochondrial fission and impaired PINK-1/PARKIN-dependent mitophagy in the intestinal mucosal layer. This was coupled with extracellular release of damaged mitochondria in the plasma of BALB/c mice following irradiation. Sublethal irradiation of the Caco-2 epithelial cell line confirmed the in vivo expulsion of mitochondria in a cell-death independent manner. exMito released upon irradiation were damaged, and had impaired ATP production. Incubation of splenocytes with damaged exMito increased the cell surface expression of immune stimulatory molecules and induced Th1 cytokine release. Furthermore, in mixed lymphocyte reactions, exMito pre-treated BALB/c stimulator cells increased the activation and proliferation of C57BL6/J responder T cells. Finally, co-transplantation of isolated damaged mitochondria in a C57BL6/J to BALB/c mouse HSCT model aggravated GVHD. The translational relevance of these findings was studied in a cohort of pediatric patients who underwent HSCT. Fractionated irradiation given with their conditioning regimen increased the abundance of circulating exMito and correlated with the incidence of GVHD. Our results suggest that modulation of exMito release could be a novel therapeutic target to prevent GVHD after HSCT.

Myelodysplastic Syndromes Benefit from Iron-Restricted Bone Marrow Transplant in Preclinical Mouse Model

Background: Hematopoietic stem cell transplantation (HSCT) remains the only fully curative therapy for diseases such as b-thalassemia, sickle cell disease, MDS and AML and represents a relevant procedure for gene therapy .Tissue iron overload and non-transferrin bound iron (NTBI) have emerged as adverse prognostic factors for post-transplant survival. Recently, we showed that - in line with observations in transplanted individuals - preparatory chemotherapy conditioning with a combination of busulfan and fludarabine in wild-type mice resulted in elevated serum iron and transferrin (Tf) saturation and elicited NTBI formation. Tf saturation and NTBI levels increased proportionally with conditioning intensity. Interestingly, we found that pre-conditioning TMPRSS6 silencing through a GalNAc-conjugated siRNA - by increasing hepcidin levels - reduced the peri-transplant elevation of Tf saturation and limited the appearance of NTBI. These results proved that NTBI formation is induced by conditioning chemotherapy in the peri-trasplant period independently of the presence of pre-existing iron overload. Aims &amp; Methods: Here we asked whether these observations hold true in conditions hallmarked by pre-existing iron overload and elevated NTBI and how iron restriction impacts on bone marrow transplant (BMT) outcome. To this aim, we applied the GalNAc TMPRSS6 siRNA as iron restriction strategy in a mouse model of myelodysplastic syndromes (MDS) and assessed its ability to reduce conditioning-elicited NTBI formation as well as its potential benefit on BMT. After TMPRSS6 siRNA administration, CD45.2 + MDS mice received conditioning chemotherapy and transplant of CD45.1 + wild-type bone marrow cells. Systemic iron parameters, engraftment and chimerism were then analyzed. Results: Importantly, conditioning exacerbated the elevated systemic iron levels in MDS mice, which was prevented by pre-conditioning TMPRSS6 silencing. Similar to our observation in wild-type mice, recipient CD45.2 + MDS mice showed a superior blood chimerism, resulting from increased bone marrow and spleen engraftment of CD45.1 + donor cells. Multilineage engraftment in bone marrow, spleen and peripheral blood was superior in iron-restricted recipient MDS mice compared to controls. Finally, donor chimerism of hematopoietic stem and progenitor cells (HSPCs) was higher in iron-restricted versus control MDS mice undergoing BMT. Conclusion: These findings demonstrate that pre-transplant conditioning profoundly alters iron homeostasis and restricting iron improves BMT outcome by increasing engraftment efficiency. Overall, these data suggest that conditioning-elicited NTBI is a critical mediator of peri-transplant toxicity and adversely impacts transplant outcome. Specifically, our observations prove that iron restriction improves donor HSPC engraftment in the recipient bone marrow, likely resulting in more efficient reconstitution of the HSPC pool and improved multilineage engraftment. Lastly, our results indicate that the peri-transplant application of novel iron restriction strategies aimed at reducing conditioning-induced NTBI - by positively affecting BMT outcome - is of potential benefit for patients undergoing BMT or gene therapy, presenting either with or without pre-transplant iron overload.

Synergistic cytotoxicity of fludarabine, clofarabine, busulfan, vorinostat and olaparib in AML cells

Combinations of nucleoside analog(s) and DNA alkylating agent(s) are used for cancer treatment as components of pre-transplant regimens used in hematopoietic stem cell transplantation. Their efficacies are enhanced by combining drugs with different mechanisms of action, which also allows a reduction in the individual drug dosages and thus potentially in toxicity to the patient. We hypothesized that addition of SAHA and olaparib, an HDAC- and a PARP-inhibitor, respectively, to the established combination of fludarabine, clofarabine and busulfan would enhance AML cell cytotoxicity. Exposure of the AML cell lines KBM3/Bu2506, MV4-11, MOLM14 and OCI-AML3 to the 5-drug combination resulted in synergistic cytotoxicity with combination indexes &amp;lt; 1. Increased protein acetylation and decreased poly(ADP-ribosyl)ation were observed, as expected. Activation of apoptosis was suggested by cleavage of Caspase 3 and PARP1, DNA fragmentation, increased reactive oxygen species, and decreased mitochondrial membrane potential. The reduction in poly(ADP-ribosyl)ation was independent of caspase activation. Several proteins involved in DNA damage response and repair were downregulated, which may be contributing factors for the observed synergism. The increased phosphorylation of DNAPKcs suggests inhibition of its kinase activity and diminution of its role in DNA repair. A similar synergism was observed in patient-derived cell samples. These findings will be important in designing clinical trials using these drug combinations as pre-transplant conditioning regimens for AML patients.

Is myelo-ablative pretransplant conditioning really myelo-ablative: Implications for radiation and nuclear accidents?

Is myelo-ablative pretransplant conditioning really myelo-ablative: Implications for radiation and nuclear accidents?

Telomere Length in Survivors of Childhood Hematologic Malignancies

Background: Telomeres are involved in maintenance of genomic stability and DNA repair. Telomeres of hematopoietic cells shorten with age, and accelerated telomere shortening is seen with replicative stress, such as during administration of chemotherapy for the treatment of cancer. We aimed to analyze leukocyte relative telomere length (RTL) among survivors of childhood hematologic malignancies, and to evaluate the associations of RTL with disease characteristics, treatment, and chronic health conditions (CHCs). Method: This study was conducted at a single center in a retrospective cohort of survivors of childhood cancer diagnosed between 2000 and 2021 with a longitudinal follow-up of ≥1 year after cessation of treatment. The peripheral blood samples were collected between June 2022 and January 2023. This study enrolled survivors of childhood hematologic malignancies with the following criteria: diagnosis before the age of 19 years, continuous maintenance of clinical remission, compliance with regular clinical follow-up, and cessation of treatment more than one year before the start of the study. Considering that telomeres shorten with age, this study limited participants to those between 18 and 35 years of age at blood sampling. The telomere PNA Kit/Fluorescein isothiocyanate (FITC) for flow cytometry (Agilent Technologies, Singapore) was used for flow FISH for the measurement of leukocyte RTL. Result: Forty-three survivors of childhood hematologic malignancies with a median follow-up period of 73 months were recruited. Median age at diagnosis and at DNA sampling were 13.8 years (range, 6-18) and 22.6 years (range, 15-34), respectively. Survivors had leukemia (57.1%), lymphoma (31.4%), and myelodysplastic syndrome (11.4%). RTL in survivors of pediatric hematologic malignancies was not significantly shorter than the predicted value for age-matched references. There was no difference in RTL according to disease subtypes ( p=0.35). Survivors who experienced relapse had significantly shorter RTL than those who did not (7.6 ± 1.0 vs. 12.1 ± 5.0, p=0.009). Those who underwent allogeneic hematopoietic stem cell transplantation (HSCT) showed significant shortening of the RTL compared with those who did not (9.4 ± 4.1 vs. 12.6 ± 5.1, p=0.039). Total body irradiation (TBI) during pre-transplant conditioning did not influence the RTL (9.5 ± 3.8 with TBI vs. 12.1 ± 5.1 without TBI, p=0.117). Among the 15 patients who underwent allogeneic HSCT, those who developed acute graft-versus-host disease (GVHD) of grade II or higher had significantly shorter RTL than those who did not (6.8 ± 1.9 vs. 11.7 ± 4.1, p=0.013). Patients with chronic GVHD tended to have shorter RTL than those without GVHD, but the p-value was not statistically significant (7.1 ± 2.8 vs. 10.9 ± 4.2, p=0.088). Seventeen patients had CHCs, with 13 having grade I and 4 having grade II. Patients with grade II CHCs had significantly shorter RTL than those without CHCs or with grade I CHCs (7.1 ± 1.6 vs. 11.5 ± 5.3, p=0.041). When the influence of multiple CHCs on RTL was examined, survivors with ≥2 CHCs had shorter RTL, but this difference was not significant ( p=0.062). Conclusion: The overall RTL in survivors of childhood hematologic malignancy was not significantly shorter than the predicted values for age-matched references. However, patients who received allogeneic HSCT showed RTL attrition compared to those who did not receive HSCT. In addition, those who had GVHD showed augmented RTL attrition. Patients with grade II CHCs had shorter RTL compared to patients without or with grade I CHCs. Although there is currently no consensus on the extent and clinical significance of accelerated shortening of the RTL, the RTL may be a potential biomarker for determining CHCs in childhood hematologic malignancies.