Conditioning Regimen For Patients Research Articles

Liver stiffness measurements predict Sinusoidal Obstructive Syndrome after hematopoietic stem cell transplantation

Sinusoidal Obstructive Syndrome (SOS) is a life-threatening complication after hematopoietic stem-cell transplantation (HSCT), characterized by post-sinusoidal portal hypertension. FibroScan is used to assess portal hypertension non-invasively. We assessed transient elastography (TE) applicability in diagnosing SOS. The study included 27 adult patients, 11 underwent TE for high SOS risk pre-HSCT, 17 underwent TE post-HSCT due to bilirubin ≥2 mg/dl with no definite diagnosis of SOS. The first group had median Liver Stiffness Measurement (LSM) of 7.4 kPa (range, 3.3–22.5). Based on LSM results, conditioning regimen was modified for six patients and two of them developed SOS. Only one patient who did not have protocol adjustment experienced SOS. No patient with LSM < 7 kPa developed SOS. The second group had median LSM of 7.7 kPa (4.4–31.5). Median LSM after HSCT was significantly higher in patients who subsequently developed established SOS (n = 10) compared to patients who did not (n = 8), with values of 10.7 kPa (5.6–31.5) and 5.9 kPa (4.4–13.8), respectively (p = 0.02). An LSM cut-off of 7.5 kPa had a sensitivity and specificity of 75 and 80% for diagnosing SOS. In conclusion, pre-HSCT LSM can help adjustment of conditioning regimen in patients with high-risk for SOS. Post-HSCT LSM can help in early diagnosis of SOS.

Decitabine in combination with idarubicin within a modified busulfan/cyclophosphamide conditioning regimen for patients with advanced myelodysplastic syndrome: A prospective multicenter clinical cohort study.

Decitabine in combination with idarubicin within a modified busulfan/cyclophosphamide conditioning regimen for patients with advanced myelodysplastic syndrome: A prospective multicenter clinical cohort study.

Radiation and Busulfan-Free Hematopoietic Stem Cell Transplantation Using Briquilimab (JSP191) Anti-CD117 Antibody-Conditioning, Transient Immunosuppression and TCRαβ + T-Cell/CD19 + B-Cell Depleted Haploidentical Grafts in Patients with Fanconi Anemia

Introduction: Fanconi anemia (FA) is a rare, genetic disorder clinically characterized by congenital abnormalities, progressive bone marrow failure (BMF), and a predisposition to malignancies. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for BMF. In patients with FA who do not have a matched sibling donor, HSCT conditioning regimens typically use reduced doses of cyclophosphamide, fludarabine and anti-thymocyte globulin (ATG) with total body irradiation (TBI) or busulfan. However, treatment is complicated by conditioning related toxicities, graft vs host disease (GvHD) and increased predisposition to malignancies later in life. Prior attempts to remove TBI from FA conditioning regimens have been unsuccessful due to increased risk of graft rejection - and alternative approaches have replaced TBI with busulfan which is still genotoxic. Objective: To reduce acute and long-term treatment-related toxicities, we have developed a first of its kind treatment intended to improve the safety of allo-HSCT through: 1) a TBI- and busulfan-free conditioning regimen consisting of briquilimab, rabbit ATG (rATG - Thymoglobulin), fludarabine, cyclophosphamide and rituximab - briquilimab (formerly called JSP191) is a monoclonal antibody (mAb) that targets human CD117 to deplete host HSCs enabling blood and immune reconstitution with minimal toxicity with the other agents being used for transient immune suppression to prevent immunologic rejection; 2) transplantation of TCRαβ + T-cell/CD19 + B-cell hematopoietic grafts - a stem cell therapy that enhances donor hematopoietic and immune reconstitution while decreasing GvHD; and 3) a pre- and post-transplant monitoring protocol to maximize engraftment. This is the first HSCT regimen to use anti-CD117 mAb-based conditioning in immunocompetent patients without concurrent use of irradiation. Methods: Patients with FA in BMF were eligible to be enrolled in this Phase 1b/2a trial to receive allo-HSCT with TCRαβ + T-cell/CD19 + B-cell depleted hematopoietic grafts from 10/10 unrelated, 9/10 unrelated or haploidentical family donors. Per the treatment schema, in this regimen a fixed dose of briquilimab was administered at 0.6 mg/kg in combination with standard FA dosing of rATG, fludarabine, cyclophosphamide and rituximab as lymphodepletion (Figure 1). Prospective pharmacokinetic measurements of briquilimab, rATG and fludarabine are included in the protocol. Results: Treatment of all of the patients on the Phase 1b portion of the study has been completed with each of the three patients showing promising safety and efficacy results (Table 1). Importantly, briquilimab treatment was well tolerated without any complications with appropriate antibody clearance of &amp;lt; 500 ng/ml prior to HSCT in all three patients. Each of the patients achieved full blood count recovery by Day +14 post HSCT with haploidentical grafts that were within specifications of the protocol. Total, CD34 +, and CD15 + donor chimerism of &amp;gt; 98% in the bone marrow has been observed in all patients with &amp;gt; 91% chimerism in all immune subsets (CD3, CD19 and CD56) at the last follow-up with 1 year of follow-up post HSCT in the first patient. None of the patients have developed acute or chronic GvHD at the time of reporting. Conclusions: All three patients in the Phase 1b portion of the study show early safety and efficacy of this approach. Briquilimab was well tolerated and all patients have shown prompt and durable donor engraftment. This data indicates that it might be possible to remove irradiation or alkylator chemotherapy from the conditioning regimen in patients with FA without matched sibling donors thus decreasing the chances for cancer predisposition in these patients that have inherited DNA repair defects.

Outcomes of Attenuated Dose Fludarabine and Melphalan Based Conditioning Regimen in Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplant for Acute Leukemia and Myelodysplastic Syndrome

Introduction: Fludarabine combined with melphalan 140 mg/m2 (FluMel140) is a commonly used reduced-intensity conditioning (RIC) regimen in patients undergoing matched related (MRD) and unrelated donor (MUD) allogeneic stem cell transplant (alloSCT). Ciurea et al Blood 2020, described outcomes of Flu 160 mg/m2 and Mel 100 mg/m2. In this study, we describe our experience of attenuated melphalan dosing 100-120 mg/m2 versus 140 mg/m2 with fludarabine 125 mg/m2 (attenuated FluMel versus regular dose FluMel). Methods: We retrospectively reviewed patients from November 2016 to April 2023 with AML, ALL or MDS undergoing alloSCT who received fludarabine and melphalan. Patients who received the lower dose of melphalan were considered to be the attenuated FluMel cohort, whereas patients receiving the melphalan 140 mg/m2 were considered to be the control cohort. Kaplan-Meier and log-rank tests were used to estimate OS. NRM and relapse incidence (RI) was calculated using competing risk analysis. R 4.2.0 (R Foundation for Statistical Computing) was used for statistical analyses. Results: A total of 134 patients [92 (68.7%) males] were evaluated. Thirty-seven (27.6%) patients received attenuated FluMel and 97 (72.4%) patients received regular dose FluMel (controls). Among the patients in the attenuated FluMel cohort, 5 (13.5%) patients also received fludarabine at doses less than 125 mg/m 2 [median 20 mg/m 2 (range 87.5-112.5 mg/m 2]. Median age at transplant was 65 years (range 30 - 76 years). The most common disease was AML [75 (56.0%) patients] ( Table 1). Patients in the attenuated FluMel group had comparable iothalamate clearance compared to control cohort (clearance &amp;lt;65 ml/min/1.73 m2: 18.9% vs. 12.4%, P = 0.52). Patients in the attenuated FluMel group had comparable rates of high/very high DRI to those in control cohort (51.4% vs. 43.3%, P = 0.91). Compared to the control cohort, patients in the attenuated FluMel group were less likely to have a matched related donor (21.6% vs. 45.4%, P = 0.02) and were more likely to receive PTCy for GVHD prophylaxis (37.8% vs. 16.5%, P = 0.02). Among the patients receiving attenuated FluMel, the median melphalan dose administered was 100 mg/m2. The median time to neutrophil engraftment was 19 days (IQR 16-21 days), and median time to platelet engraftment was 18 days (range 12-25 days). Eleven (29.7%) patients developed post-alloSCT mucositis, and 3 (8.1%) patients developed grade 3-4 mucositis. All the patients in the attenuated FluMel group achieved 100% CD33 donor chimerism at day +30 (n=35) and day +100 (n=28) after alloSCT. Similarly, 26 (74.3%, n = 35) patients achieved ≥ 95% CD3 donor chimerism at day +30 after alloSCT and 23 (82.1%, n = 28) patients achieved ≥ 95% CD3 donor chimerism at day +100 after alloSCT. Median follow-up of the entire cohort after alloSCT was 2.3 years (95% CI 2.1-2.5 years). Median follow-up was 1.5 years in the attenuated FluMel cohort and 2.5 years for the control cohort ( P&amp;lt;0.001) . Survival was similar among patients receiving attenuated FluMel vs. control cohort (2-year OS 74.7% vs. 65.0%, P = 0.28). At 2 years post-alloSCT, the attenuated FluMel and control cohort had similar non-relapse mortality (19.9% vs. 24.4%, P=0.58) and relapse (22% vs. 15.2%, P=0.51). The attenuated FluMel was not associated with an increased incidence of relapse (HR 1.36, 95% CI 0.50-3.73, P=0.55) or NRM (HR 0.74, 95% CI 0.28-1.95, P = 0.55). GVHD-free relapse free (GRFS) survival was also similar among the attenuated Flu/Mel and control cohort (1-year GRFS rate 41.1% vs. 45.6%, P = 0.8). Among the patients receiving PTCy for GVHD prophylaxis, the 2-year OS in patients receiving attenuated FluMel was higher than the control group, but it was not statistically significant (2-year OS rate: 90% vs. 55%, P=0.37, Figure 1). Compared to the control group, the attenuated FluMel group had similar rates of NRM at 100 days (10% vs. 12.5%), 1 year (NA vs. 25%) and at 2 years after alloSCT (NA vs. 25%, P=0.54). GRFS at 1 year was also similar between the attenuated FluMel and control group (68.6% vs. 43.8%, P = 0.69). Conclusion: The attenuated dosed FluMel conditioning is a safe and effective regimen for elderly patients with acute leukemia and MDS, and is non-inferior to regular dose FluMel. Among patients receiving PTCy for GVHD prophylaxis, the lower dose of melphalan was non-inferior to regular dose FluMel for survival outcomes. Larger studies are needed to confirm our findings.

Total Marrow and Lymphoid Irradiation (TMLI) -Based Conditioning Regimen in Patients with Acute Leukemia Undergoing Allogeneic Hematopoietic Cell Transplant with Measurable Residual Disease

Relapse of primary hematologic malignancy remains the leading cause of treatment failure afterallogeneic Hematopoietic cell transplantation (allo-HCT). Multiple studies have shown that presence of measurable residual disease (MRD), at the time of HCT, irrespective of the detection method, is associated with lower overall survival (OS) and relapse-free survival (RFS). In a recent meta-analysis of 11,151 patients with AML, Short et al., reported 5-year disease-free survival (DFS) of 25% for patients who have detectable MRD pre -HCT, compared to 64% for those without MRD. The 5-year OS was 34% and 68% for patients with or without MRD at HCT (JAMA Oncology 2020). In AML patients with genomic evidence of MRD before allo-HCT, myeloablative conditioning (MAC) regimens result in improved survival when compared to reduced intensity conditioning (RIC); (Hourigan et al, JCO 2020). Our center has pioneered and developed Total marrow and lymphoid irradiation (TMLI) that allows for delivery of higher dose of radiation to the sites with high disease burden (bone marrow and lymphoid organs), while sparing healthy tissues. In an ongoing Phase 2 trial (NCT02094794), we delivered TMLI (20Gy) with high dose chemotherapy to patients with high-risk leukemias (ALL or AML) undergoing allo-HCT from an HLA matched or mismatched donor. Here, we report on the results of our prospective analysis on a subset of patients of NCT02094794 who underwent allo-HCT with morphologic remission but had detectable MRD status in their pre HCT bone marrow biopsy (n=30). Conditioning regimen comprised of TMLI on days -9 to -5 (total of 20Gy), etoposide (60 mg/kg) on day -4, and cyclophosphamide (100mg/kg) on day -2. Unmanipulated peripheral blood stem cells (PBSC) graft from 10/10 HLA matched related or unrelated donor was infused on day 0 and graft-versus-host disease (GVHD) prophylaxis was tacrolimus and sirolimus-based. TMLI was delivered by intensity modulated radiation therapy (IMRT). MRD assay was done by either University of Washington flow cytometry with 0.01% - 0.1 % sensitivity, FISH/conventional cytogenetics, or NGS-based assays. Patient and HCT characteristics are summarized in Table 1. Briefly, the median age at the time of HCT was 36 years (range: 16-59) with the majority of patients receiving PBSC grafts (87%). Donors were match related (67%) or match unrelated (33%). The underlying diagnosis was AML (n=22; 73%), ALL (n=7; 23%), or CML-BC (n=1; 3%). Karnofsky performance status was 80-100 in 90% of patients and HCT-CI ≥3 was seen in 35% of patients. Pre-HCT MRD + status was documented by Flow cytometry MRD assay in 17 patients [AML (n=14) and ALL (n=3)], with mean MRD positivity of 2.9 % (range: 0.02-5.6%) for AML and 0.4% (range: 0.003-1.7%) for ALL patients. Thirteen additional patients had MRD positive status confirmed by FISH/cytogenetics (n=6 patients) or NGS (n=7). With a median duration follow up of 22.3 months (range: 6.0-81.1), the 1 and 2-year OS were 68% (95% CI: 0.47-0.82) and 59% (95% CI: 0.38-0.75), respectively. The 1 and 2- year disease-free survival (DFS) were 55% (95% CI: 0.34-0.71) and 45% (95% CI: 0.26-0.63), while the cumulative incidence (CI) of relapse at 1 and 2 years were 28% (95% CI: 0.13-0.46) and 33% (95% CI: 0.16-0.51), respectively. At day 100 post-HCT, the CI of NRM was 7%, grade 2-4 acute GVHD was 40% and Grade 3-4 acute GVHD was 13%. The CI of NIH moderate- severe chronic GVHD at 1- year was 35% (95% CI: 0.17-0.52). No difference in outcomes were noted in patients who were MRD positive by UWFC vs FISH/NGS testing. In conclusion, TMLI based conditioning regimen in patients undergoing allo-HCT with MRD+ disease from matched donors is associated with improvement in 2-year RFS/OS and is associated with low NRM compared to historic controls. The current phase 2 study is enrolling patients at our center.

Identifying the Optimal Conditioning Intensity of Hematopoietic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia in Complete Remission

Background Allogeneic hematopoietic stem cell transplantation (HSCT) as consolidation therapy is considered a curative option for acute myeloid leukemia (AML) in complete remission (CR) to prevent relapse. Many studies have investigated the optimal conditioning intensity, comparing reduced-intensity conditioning regimen (RIC) and myeloablative conditioning regimen (MAC) for patients with AML in CR. However, inconsistent results have been observed, possibly due to selection biases and significant heterogeneous treatment effects when focusing on average treatment effect. Some studies have attempted to assess treatment effects in specific subgroups, highlighting the heterogeneity conditioning intensity's impact. However, these analyses typically examined one factor at a time, overlooking potential multiple-factor combinations that might contribute to such heterogeneity.To address these limitations and surpass conventional comparison studies and subgroup analyses, machine-learning methods for group identification have been developed. In this study, we aimed to identify patient groups in which MAC or RIC had a superior PFS in patients with AML in CR using a machine-learning approach. Methods Our study included 3273 patients aged 40-69 years with AML in CR from the TRUMP2. These patients were divided into training (N=2020) and validation cohorts (N=1253). In the training cohort, we employed a group identification model to identify patient subsets. Preprocessing of variables was performed to ensure the ease of use in clinical practice. We modeled the magnitude of interaction between treatment and covariates without the main effect of covariates, thus leading to the construction of a scoring system that measures the individualized-treatment effect. The objective variable was set as 1-year PFS, and the interaction effects between treatment and covariates were estimated using a regression model with propensity score weight and LASSO regularization. The sum of the interaction term between treatment and covariates was defined as the “Conditioning Intensity Score”. Patients were categorized into high-score and low-score groups using a cut-off level of median in patients who received RIC. Subsequently, in the validation cohort, we estimated the average treatment effect of RIC compared to MAC for each group with hazard ratios (HR) using inverse treatment probability weight analysis. Results In the training cohort, the median age was 55 years (IQR, 48-61 years), with 1110 (55%) male patients. Among them, 666 (33%) received RIC, while the others underwent MAC. Conditioning Intensity Model was developed and consistent with followings; age over 49 (1.4 points), age over 49 and male (0.8 points), age over 49 and poor karyotype (0.5 point), age over 49 and cord blood transplantation (0.9 points), poor karyotype (-1.6 points), poor karyotype and primary induction failure (8.0 points), poor karyotype and bone marrow transplantation (-5.3 points), cord blood transplantation and hematopoietic cell transplant comorbidity index over 2 (2.1 points) and cord blood transplantation and extra bone marrow involvement (-8.6 points). The cut-off level was set as 2.2. The weighted HR of RIC on 1-year PFS was 0.56 (95%CI; 0.40-0.79, p &amp;lt; 0.001) in the high-score group and 1.23 (95%CI: 0.97- 1.57, p=0.094) in the low-score group. In the entire validation cohort, there were no significant differences in PFS between the RIC and MAC (67.7% [95% CI: 62.1-70.3%] in the RIC group vs. 70.3% [95% CI: 67.2-73.1%] in the MAC group, P=0.318). Patients were divided into two groups based on Conditioning Intensity Score. In the high-score group, the 1-year PFS was 73.9% (95% CI: 65.0-80.9%) in the RIC group vs. 66.2% (95% CI: 58.3-73.0%) in the MAC group ( P=0.181), with a weighted HR of 0.69 (95% CI: 0.43-1.11) for PFS in the RIC group compared to that the MAC group ( P=0.125) (Figure left). Conversely, in the low-score group, the 1-year PFS was 63.7% (95% CI: 56.3-70.2%) in the RIC group vs. 71.2% (95% CI: 67.8-74.2%) in the MAC group ( P=0.031), with a weighted HR of 1.35 (95% CI: 0.96-1.89) in the RIC group compared to the MAC group (log-rank P=0.086) (Figure right). Conclusion In conclusion, we have demonstrated the feasibility of utilizing a machine learning method for subgroup identification of conditioning regimens in patients with AML in CR. This established model holds promise for designing patient-specific regimens.

Impact of immunosuppression intensified conditioning regimen for patients with strong positive pre-transplantation donor-specific anti-HLA antibodies (DSAs) undergoing haploidentical hematopoietic stem cell transplantation

Objective: To explore the efficacy of immunosuppression intensified conditioning regimen in patients who have strongly positive donor-specific Anti-HLA antibodies (DSAs) and received a haploidentical hematopoietic stem cell transplantation (haplo-HSCT) . Methods: Clinical data of 10 patients with strongly positive pretransplant DSAs (defined as MFI ≥10000) were retrospectively analyzed in this study. All of them received a haplo-HSCT in the Hematology Department of Shanghai Zhaxin Traditional Chinese & Western Medicine Hospital. Results: ① Of all ten patients, three were males, and seven were females, with a median age of 53.5 (36-64) years. Of the 10 patients, three were diagnosed with acute myeloid leukemia, two were myelodysplastic syndromes (MDS), two were chronic myelomonocytic leukemia (CMML), two were in an accelerated phase of chronic myeloid leukemia (CML-AP), and one was primary myelofibrosis (PMF). ② Conditioning regimen consisted of fludarabine (Flu) /busulfan (Bu) combined with whole-body irradiation (TBI) /cyclophosphamide (Cy). ③ On the seventh day after transplantation, the median pretransplant DSA level was MFI 15 999 (10 210-23 417) and 10 787 (0-22 720). ④ Eight patients acquired hematopoietic reconstitution; the median time of neutrophil engraftment was 14 (10-16) days; and 18 (14-20) days for platelet engraftment. After a median follow-up of 12.5 (1.5-27) months, primary graft failure was found in one patient and another with poor graft function. Seven patients remained in a disease remission state, and all were DSA-negative. Conclusions: An intensified immunosuppression conditioning regimen can efficiently decrease the level of donor-specific anti-HLA antibodies (DSAs), leading to good short-term efficacy.

FLUDARABINE-BASED LOW-INTENSITY CONDITIONING FOR FANCONI ANEMIA IS ASSOCIATED WITH GOOD OUTCOMES IN APLASTIC ANEMIA BUT NOT IN MDS - A SINGLE-CENTER EXPERIENCE

Background: Hematopoietic stem cell transplantation [HSCT] is the only curative option for Fanconi Anemia (FA) patients with hematological abnormalities.&#x0D; Materials and Methods: This is a retrospective analysis of patients with FA who underwent a matched-related donor HSCT.&#x0D; Results: Sixty patients underwent 65 transplants between 1999-2021 using a fludarabine-based low-intensity conditioning regimen. The median age at transplant was 11 years (range: 3-37). Aplastic anemia (AA) was the underlying diagnosis in 55 (84.6%) while 8 (12.4%) had myelodysplastic syndrome (MDS) and 2 (3%) had acute myeloid leukemia (AML). The conditioning regimen used was fludarabine with low-dose cyclophosphamide for aplastic anemia and Fludarabine with low-dose busulfan for MDS/AML. Graft versus host disease (GVHD)prophylaxis consisted of cyclosporine and methotrexate. Peripheral blood stem cells was the predominant graft source (86.2%). Engraftment occurred in all but 1 patient. The median time to neutrophil and platelet engraftment was 13 days (range: 9-29) &amp; 13 days (range: 5-31), respectively. Day 28 chimerism analysis showed complete chimerism in 75.4 % and mixed chimerism in 18.5%. Secondary graft failure was encountered in 7.7%. Grade II–IV acute GVHD occurred in 29.2% while Grade III-IV acute GVHD occurred in 9.2%. Chronic GVHD was seen in 58.5% and was limited in most patients. The median follow-up is 55 months [range: 2-144] &amp; the 5-year estimated overall survival (OS) is 80.2 ± 5.1%. Secondary malignancies were noted in 4 patients. The 5-year OS was significantly higher in patients undergoing HSCT for AA (86.6 + 4.7%) as compared to MDS/AML (45.7+16.6%) (p= 0.001).&#x0D; Conclusion: SCT using a fully matched donor provides good outcomes with low-intensity conditioning regimens in patients with FA who have an aplastic marrow.

Myeloablative fractionated busulfan-based conditioning regimen in patients with AML and MDS: Results of a randomized clinical trial comparing 2 fractionation schedules.

7051 Background: Hematopoietic stem cell transplantation (HSCT) cures leukemias, but comes at a cost of higher toxicity and non-relapse mortality (NRM). We previously showed that fractionating the busulfan (Bu) dose and starting it on day -13 instead of day -6, leads to lower toxicity and permits delivery of a myeloablative regimen, even to older patients. We designed a single institution randomized trial to validate the concept of fractionation and to test the hypothesis that further fractionation by starting chemotherapy on day -20 further reduces toxicity and lowers NRM without increasing relapse risk. Methods: Patients with AML or MDS, 18 to 70 years old, with a matched related or unrelated donor were eligible if they had adequate organ function. Patients were randomized to one of two arms: The shorter arm consisted of outpatient Bu 80mg/m2 on days -13 and -12, while the longer arm consisted of outpatient Bu 80mg/m2 on days -20 and -13. The rest of the regimen and GVHD prophylaxis were similar in both arms: On days -6 to -3, fludarabine 10mg/m2, cladribine 10mg/m2 and Bu dosed to achieve total Bu exposure of 20,000 ± 12% µMol-min for the whole course, including outpatient doses. Additionally, the last 33 patients received venetoclax from days -22 to -3 in both arms. The GVHD prophylaxis was tacrolimus and mini-methotrexate in the first 29 patients and tacrolimus and cyclophosphamide in the remainder. The only difference between the two arms was if busulfan was started on day -20 or not. Results: A total of 116 patients were randomized, 59 to the shorter day -13 arm and 57 to the longer day -20 arm. Median age was 59 in the day -13 arm and 57 in the -20 arm. 70.7% had AML. 41.4% were transplanted in first complete remission. The characteristics of the two groups were well-balanced. The median follow-up in the 67 surviving patients was 48.9 months. More patients in the day -13 group experienced grade ≥3 toxicities than in the day -20 group (93.2% vs. 73.7%, p = 0.005). The difference in toxicity led to a reduction of the 3-year NRM (19% vs. 7%, p = 0.067). There was no difference in relapse rate (p = 0.99) (Table). Conclusions: Further fractionating busulfan and moving just one dose of busulfan 1 week earlier reduces toxicities and may lower NRM, without increasing relapse rate. Clinical trial information: NCT02250937 . [Table: see text]

Busulfan versus treosulfan conditioning for acute myeloid leukemia and myelodysplastic syndrome: A systematic review and meta-analysis.

e19032 Background: Busulfan containing myeloablative conditioning regimens are widely used before allogeneic hematological stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Treosulfan-based conditioning regimens are a potential alternative with potent myelotoxic immunosuppressive characteristics and favorable extramedullary toxicity profile compared to busulfan. In order to determine the optimal conditioning regimen, we conducted a systematic review and meta-analysis to compare the efficacy and safety outcomes of busulfan and treosulfan based conditioning regimens in patients with AML/MDS. Methods: A retrospective systematic literature search was undertaken on PubMed, Cochrane, Embase and Clinicaltrials.gov, using MeSH terms and relevant keywords for AML, MDS, busulfan and treosulfan, to retrieve studies published prior to February 5, 2023. Efficacy outcomes were overall survival (OS), disease-free survival (DFS), and relapse. Safety outcomes included non-relapse mortality (NRM), acute (a) and chronic (c) graft-versus-host disease (GvHD). The random-effects model with the Mantel-Haenszel method was used to pool risk ratios (RR) for dichotomous variables in Revman version 5.4. Results: The initial search retrieved 1094 articles. After removal of duplicates, reviews and non-relevant articles, data was extracted from seven different studies. Busulfan and treosulfan were employed in 4706 and 1979 patients, respectively. The median age ranged from 55 to 61 years, and the median follow-up ranged from 14 to 58 months. The treosulfan and busulfan doses administered ranged from 10-42 g/m2 and 0.8-12.8 mg/kg, respectively. Treosulfan was superior to busulfan in terms of OS (RR 1.39, 95% CI 1.15-1.68, p-value 0.0007, I2 58%), DFS (RR 1.39, 95% CI 1.10-1.75, p-value 0.006, I2 60%) and NRM (RR 0.95, 95% CI 0.90-1.00, p-value 0.05, I2 67%). The two regimens were comparable in terms of relapse (RR 0.96, 95% CI 0.89-1.04, p-value 0.33, I2 76%), aGvHD (RR 1.00, 95% CI 0.65-1.54, p-value 1.00, I2 94%) and cGvHD (RR 1.00, 95% CI 0.95-1.05, p-value 0.92, I2 0%). Conclusions: Treosulfan was superior in terms of OS, EFS and NRM, whereas both regimens were comparable in terms of relapse, aGvHD and cGvHD. Treosulfan may be more favorable compared to busulfan as conditioning in AML/MDS. Large scale prospective studies are needed to confirm the most suitable option.

Total Marrow Irradiation for Second Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Advanced Acute Leukemia

Second allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment option for patients with acute leukemia who relapse after a first HSCT. Although myeloablative conditioning (MAC) regimens before the first HSCT are considered superior to reduced- intensity conditioning (RIC) in terms of disease control in acute leukemia patients, the optimal conditioning regimen for the second allogeneic HSCT remains controversial. The most important prognostic factors are the remission disease phase at the time of the second HSCT and an interval >12 months from the first HSCT to the second HSCT. Total marrow irradiation (TMI) is an advanced high-precision radiation treatment that delivers therapeutic doses over extensively selected targets while substantially reducing radiation to vital organs compared to conventional total body irradiation (TBI). Here we report the results of a retrospective analysis of second allogeneic HSCT treated with TMI as an MAC regimen with the intent of limiting toxicity. We investigated the efficacy of high dose per fraction TMI in combination with thiotepa, fludarabine, and melphalan in 13 consecutive patients with acute leukemia who had relapsed after a first allogeneic HSCT treated between March 2018 and November 2021. Donor type was haploidentical in 10 patients, unrelated in 2 patients, and HLA-identical sibling in 1 patient. The conditioning regimen consisted of 8 Gy TMI in 5 patients on days -8 and -7 and 12 Gy TMI in 8 patients on days -9 to -7, plus thiotepa 5 mg/kg on day -6, fludarabine 50 mg/day on days -5 to -3, and melphalan 140 mg/day on day -2. The TMI was delivered at the dosage og 4 GY for 2 consecutive days (total = 8 GY) or for 3 consecutive days (total = 12 GY). The median patient age was 45 years (range, 19 to 70 years); 7 patients were in remission, and 6 had active disease at the time of their second allogeneic HSCT. The median time to a neutrophil count of >.5×109/L was 16 days (range, 13 to 22 days), and the median time to a platelet count of >20×109/L was 20 days (range, 14 to 34 days). All patients showed complete donor chimerism on day +30 post-transplantation. The cumulative incidence of grade I-II acute graft-versus-host disease (GVHD) was 43%, and that of chronic GVHD was 30%. The median duration of follow-up was 1121 days (range, 200 to 1540 days). Day +30 and +100 transplantation-related mortality (TRM) was 0. The overall cumulative incidence of TRM, relapse rate, and disease free-survival were 27%, 7%, and 67%, respectively. This retrospective study demonstrates the safety and efficacy of a hypofractionated TMI conditioning regimen in patients with acute leukemia undergoing second HSCT with encouraging outcomes in terms of engraftment, early toxicity, GVHD, and relapse.

Hematopoietic stem cell transplantation with reduced toxicity conditioning regimen in mitochondrial neurogastrointestinal encephalopathy syndrome.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder due to mutations in the TYMP gene. Clinical findings are characterized by neurologic manifestations and severe gastrointestinal dysfunction. The syndrome is usually fatal, the most effective treatment appears to be hematopoietic stem cell transplantation (HSCT). In this retrospective study, we evaluated HSCT that was performed using a reduced toxicity myeloablative conditioning regimen in patients with MNGIE at our center. A total of six allogeneic transplant procedures were performed in four patients. Three patients had fully matched donors, and one patient had a haploidentical donor. Treosulfan-based myeloablative conditioning regimen was applied in five of six transplants. Bone marrow was used as a stem cell source. One patient is being followed up in the 4th year of posttransplant with full chimeric and without graft versus host disease (GVHD). One patient died of acute stage IV gastrointestinal system GVHD. Two patients underwent second transplantation due to engraftment failure, one of which was the patient who had a haploidentical transplant. Treosulfan-based regimen is well tolerated, although engraftment failure with this conditioning regimen can be a significant problem. We share our haploidentical transplant experience, which will be the first reported case in the literature.

Improving total body irradiation with a dedicated couch and 3D-printed patient-specific lung blocks: A feasibility study.

Total body irradiation (TBI) is an important component of the conditioning regimen in patients undergoing hematopoietic stem cell transplants. TBI is used in very few patients and therefore it is generally delivered with standard linear accelerators (LINACs) and not with dedicated devices. Severe pulmonary toxicity is the most common adverse effect after TBI, and patient-specific lead blocks are used to reduce mean lung dose. In this context, online treatment setup is crucial to achieve precise positioning of the lung blocks. Therefore, in this study we aim to report our experience at generating 3D-printed patient-specific lung blocks and coupling a dedicated couch (with an integrated onboard image device) with a modern LINAC for TBI treatment. TBI was planned and delivered (2Gy/fraction given twice a day, over 3 days) to 15 patients. Online images, to be compared with planned digitally reconstructed radiographies, were acquired with the couch-dedicated Electronic Portal Imaging Device (EPID) panel and imported in the iView software using a homemade Graphical User Interface (GUI). In vivo dosimetry, using Metal-Oxide Field-Effect Transistors (MOSFETs), was used to assess the setup reproducibility in both supine and prone positions. 3D printing of lung blocks was feasible for all planned patients using a stereolithography 3D printer with a build volume of 14.5×14.5×17.5 cm3. The number of required pre-TBI EPID-images generally decreases after the first fraction. In patient-specific quality assurance, the difference between measured and calculated dose was generally<2%. The MOSFET measurements reproducibility along each treatment and patient was 2.7%, in average. The TBI technique was successfully implemented, demonstrating that our approach is feasible, flexible, and cost-effective. The use of 3D-printed patient-specific lung blocks have the potential to personalize TBI treatment and to refine the shape of the blocks before delivery, making them extremely versatile.

Second Allogeneic Hematopoietic Stem Cell Transplantation for Hemophagocytic Syndrome with Engraftment Failure

This study aims to assess the efficacy of second allogeneic hemopoietic stem cell transplantation (allo-HSCT) for treating hemophagocytic syndrome with first engraftment failure. Among a total of 35 patients who underwent allo-HSCT between June 2015 and July 2021 for HLH, 10 patients who underwent a second HSCT following graft rejection were retrospectively analyzed. Various factors, such as the treatment course and outcome, the remission status, donor selection, and the conditioning regimen of patients before second allo-HSCT, were scrutinized for transplant-related complications and transplant-related mortality, as well as transplant outcomes. All the subjects have achieved complete donor engraftment, in which the neutrophils and platelets engraftment occurred in a median time of 12 d (range 10–19 d) and 24 d (range 11–97 d), respectively. Among the selected subjects, 20% of patients are diseased due to transplant-related thrombotic microangiopathy. Further, 90% of patients are diagnosed with aGVHD, in which 3 of them with grade I aGVHD, one patient with grade II aGVHD, two patients with grade III GVHD, and three patients with localized chronic GVHD. Moreover, 70% of patients showed signs of combined viral infections. Despite the complex symptoms, the overall survival rate is around 80%, with transplant-related mortality and the incidence of post-transplant GVHD of 20% and 60%, respectively. Together, our findings indicated that the second allo-HSCT showed great potential in treating hemophagocytic syndrome with engraftment failure.

Efficacy and Safety of a Novel Non-Myeloablative Conditioning Regimen for Hematopoietic Cell Transplantation in Adults with Severe Aplastic Anemia

Introduction The distinct "age effect" that exists in severe aplastic anemia (SAA) following hematopoietic cell transplantation (HCT) favors the use of reduced intensity conditioning regimens in patients >40 years. For older adults, overall survival and disease-free survival (DFS) is reduced with increasing age and unrelated donor transplant are associated with higher rates of graft failure, Epstein-Barr virus (EBV) reactivation, and post-transplant lymphoproliferative disorders (PTLD) (Rice C, et al. BBMT 2019.). To overcome this, a novel, non-myeloablative conditioning regimen called FCR, which consists of fludarabine, cyclophosphamide, and rituximab, was designed at Vanderbilt University Medical Center (VUMC) and the associated VA Tennessee Valley Healthcare System (TVHS) for use in all SAA patients. This regimen was subsequently evaluated in the first 11 SAA patients treated at VUMC/TVHS and found to result in lower toxicity, graft-versus-host disease (GVHD), and viral reactivation with no graft failure or relapse compared to historical controls (Gatwood KS, et al. BMT 2018.). Given these initial favorable results, FCR has now been expanded as the preferred conditioning regimen for all SAA patients undergoing HCT at our center, warranting follow-up evaluation in a larger cohort. Methods Utilizing institutional registries, all SAA patients were identified who underwent first allogeneic HCT using an FCR regimen (Figure 1) between January 2016 and May 2022. VUMC and TVHS Institutional Review Boards approved this retrospective analysis. Outcomes analyzed included time to engraftment, incidence of graft failure, incidence of acute GVHD (aGVHD) and chronic GVHD (cGVHD), rate of viral reactivation, post-HCT disease status, and number of inpatient hospital days through day +100. An analysis of 1-year GVHD-free, relapse-free survival (GRFS) was conducted in evaluable patients, with differences between the curves determined using log-rank tests. Results Twenty-four SAA patients underwent HCT from January 26, 2016 to May 11, 2022, the majority of which were male with a median age of 43.5 years (range: 22-62). All patients received at least one line of therapy prior to HCT with the most common treatment being the combination of cyclosporin A with anti-thymocyte globulin with or without eltrombopag and/or corticosteroid. Median time from diagnosis to transplantation was 434.5 days (range: 84-6408). Patients received transplants from matched related (n=8), haploidentical (n=2), and matched unrelated donors (n=14) using either a peripheral blood (PB) or bone marrow (BM) stem cell source (PB=15, BM=9). Median time to neutrophil and platelet engraftment was 14 days (range: 10-25) and 18 days (range: 10-38), respectively. No patients experienced graft failure. At median follow-up of 806.5 days (range: 72-2180) post-transplant, all patients were alive and in remission. No patients developed grade III-IV aGVHD and no differences in grade I-II aGVHD rates were noted based on stem cell source. By date of last follow-up, mild to moderate cGVHD graded per 2014 NIH criteria developed in 7 and 3 patients, respectively. There were no cases of severe cGVHD. Only 2 patients experienced a viral reactivation (cytomegalovirus [CMV]=1, EBV=1) by date of last follow-up. The case of EBV reactivation did not require treatment and did not progress to PTLD. The median number of inpatient hospital days required post-engraftment through the first 100 days post-transplant was 5 days (range: 0-21). The unadjusted Kaplan-Meier estimate of 1-year GRFS was 86.3% (95% CI: 72.8%-100%) (Figure 2), with moderate cGVHD accounting for all GFRS events in the study cohort. Conclusions The use of our novel non-myeloablative conditioning regimen in SAA is well tolerated with 0% non-relapse mortality and 100% DFS with low GVHD rates at 1-year post-transplant. Despite a high-risk population with median age >40 years, using primarily matched unrelated donors, and majority peripheral blood stem cell source, there were no deaths and rates of complications remained low. This study further supports the findings of our previous study, redemonstrating low rates of toxicity, severe GVHD and viral reactivation with no graft failure, relapse, or mortality. The use of these regimens needs to be validated in a larger cohort as they have the potential to provide a new standard of care for pre-HCT conditioning in SAA patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Treosulfan-based conditioning vs. low-dose busulfan-based conditioning for allogeneic hematopoietic stem cell transplantation: a cost-utility analysis in Poland

Introduction: In Poland, busulfan conditioning is used for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Cost-utility analyses comparing alternative conditioning regimens in patients undergoing allo-HSCT have not been conducted so far. Material and methods: A United Kingdom-based partitioned survival model was adapted to the Polish setting to compare treosulfan to low-dose busulfan conditioning regimen from the public payer’s perspective in Poland. Patient characteristics, overall survival (OS), event-free survival (EFS), and the rate of adverse events were obtained from the randomized MC-FludT.14/L trial. Parametric survival models of up to 5 years (the cure threshold), with subsequent mortality defined using survival of the general population of Poland adjusted for cancer survivors, were used to extrapolate OS and EFS beyond the trial duration. Published utilities were adjusted for age using age-dependent general population utilities. The costs of treatment, adverse events, and inpatient/outpatient care were assessed via official remuneration schemes. Results: Treosulfan-based conditioning outperformed low-dose busulfan, i.e. it was more effective with incremental quality-adjusted life years (QALY) of 0.78 and less expensive by 1,139 PLN per patient over the lifetime horizon. Deterministic sensitivity analyses revealed treosulfan was highly cost-effective (i.e. incremental cost-utility ratio was lower than the gross domestic product per capita in Poland) compared to low-dose busulfan, if most uncertain parameters are changed or alternative scenarios are implemented. The probability of treosulfan being cost-effective with a threshold of 155,514 PLN was 99.6%. Conclusions: Compared to low-dose busulfan, treosulfan is a highly cost-effective conditioning regimen for allo-HSCT patients ineligible for standard conditioning regimens.

Rapid and accurate method for quantifying busulfan in plasma samples by isocratic liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Administration of busulfan is extending rapidly as a part of a conditioning regimen in patients undergoing hematopoietic stem cell transplantation (HSCT). Monitoring blood plasma levels of busulfan is recommended for identifying the optimal dose in patients and for minimizing toxicity. The aim of this research was to validate a simple, rapid, and cost-effective analytical tool for measuring busulfan in human plasma that would be suitable for routine clinical use. This novel tool was based on liquid chromatography coupled to mass spectrometry. Human plasma samples were prepared using a one-step protein precipitation protocol. These samples were then resolved by isocratic elution in a C18 column. The mobile phase consisted 2mM ammonium acetate and 0.1% formic acid dissolved in a 30:70 ratio of methanol/water. Busulfan-d8 was used as the internal standard. The run time was optimized at 1.6min. Standard curves were linear from 0.03 to 5mg/L. The coefficient of variation(%CV) was less than 8%. The accuracy of this method had an acceptable bias that fell within 85-115% range. No interference between busulfan and the interfering compound hemoglobin, lipemia, or bilirubin not even at the highest concentrations of compound was tested. Neither carryover nor matrix effects were observed using this method. The area under the plasma drug concentration-time curves obtained for 15 pediatric patients who received busulfan therapy prior to HSCT were analyzed and correlated properly with the administered doses. This method was successfully validated and was found to be robust enough for therapeutic drug monitoring in a clinical setting.

Myeloablative Versus Reduced-Intensity Conditioning With Fludarabine/Busulfan for Myelodysplastic Syndrome: A Propensity Score-Matched Analysis

There are limited data comparing myeloablative conditioning with fludarabine/busulfan (Flu/Bu4) and reduced-intensity conditioning with fludarabine/busulfan (Flu/Bu2) in patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed nationwide registry data and compared the outcomes of adult patients with MDS receiving Flu/Bu4 and Flu/Bu2 by propensity score (PS) matching. Patients who met the following criteria were eligible for enrollment: (1) age ≥16 years; (2) diagnosis of de novo MDS; (3) first allo-HSCT between 2006 and 2018; (4) related bone marrow transplantation (BMT) or peripheral blood stem cell transplantation from an HLA-matched donor, unrelated BMT from an HLA-matched or HLA-1 allele–mismatched donor, or unrelated cord blood transplantation; and (5) receiving Flu/Bu4 or Flu/Bu2 as a conditioning regimen. Flu/Bu4 comprised intravenous busulfan (total dose, 12.8 mg/kg) combined with fludarabine (total dose, 125–180 mg/m2). Flu/Bu2 comprised intravenous busulfan (total dose, 6.4 mg/kg) combined with the same dose of fludarabine. To minimize selection bias and confounding factors, we performed a propensity score (PS)-matched analysis. The primary endpoint was overall survival (OS) after allo-HSCT. A total of 3386 patients with de novo MDS underwent their first allo-HSCT between 2006 and 2018. Among them, 202 patients were assigned each to the Flu/Bu4 and Flu/Bu2 groups after PS-matched analysis. The median age was 61 (interquartile, 57-65) years. The 3-year OS rates were 44.8% (95% confidence interval [CI], 37.1–52.1%) and 46.9% (95% CI, 39.2–54.2%) in the Flu/Bu4 and Flu/Bu2 groups, respectively (P = .67). The 3-year rates of graft-versus-host disease (GVHD)–free survival, relapse-free survival (GRFS) were 28.8% (95% CI, 22.2–35.7%) and 33.0% (95% CI, 26.2–40.0%), respectively (P = .36). The 3-year cumulative incidence rates of relapse were 28.9% (95% CI, 22.6–35.6%) and 30.0% (95% CI, 23.6–36.6%), respectively (P = .47). The 3-year cumulative incidence rates of non-relapse mortality (NRM) were 28.2% (95% CI, 21.7–35.0%) and 27.1% (95% CI, 20.6–33.9%), respectively (P = .60). The 100-day cumulative incidence rate of grade II–IV acute GVHD was significantly higher in the Flu/Bu4 group than in the Flu/Bu2 group (41.7% [95% CI, 34.8%–48.4%] versus 29.3% [95% CI, 23.2%-35.7%], P = 0.012). To identify patients who had more favorable outcomes with 1 of the 2 regimens, we compared the outcomes between the 2 groups after stratifying by age, hematopoietic cell transplantation-comorbidity index, cytogenetic risk, disease status at allo-HSCT, stem cell source, and donor type. OS, GRFS, relapse, and NRM did not differ between the 2 groups in any subgroup analyses. There were no significant interactions between the choice of conditioning regimens and any other factors. There are no differences in survival between Flu/Bu4 and Flu/Bu2, although our study population was highly selected by PS matching. Data from more patients and prospective studies are needed to determine the optimal intensity of conditioning regimens in patients with MDS.

Impact of concurrent gabapentin or pregabalin with high-dose melphalan in patients with multiple myeloma undergoing autologous hematopoietic stem cell transplant.

Melphalan is an alkylating agent used in both autologous (ASCT) and allogeneic stem cell transplantation. It is a substrate of L-type amino acid transporter-1 (LAT-1) and LAT-2, which are involved in its tissue penetration and elimination. Gabapentin and pregabalin, common concomitant medications in patients with multiple myeloma undergoing ASCT, are also substrates of LAT transporters, raising concern for potential competitive inhibition of melphalan transport. We evaluated whether concurrent use of gabapentin or pregabalin in patients receiving high-dose melphalan (≥140mg/m2 ) prior to ASCT impacted frequency and severity of melphalan-related adverse events. We aimed to determine if concurrent administration of gabapentin or pregabalin and melphalan increased melphalan toxicity. This was a single-center, retrospective evaluation including patients ≥18years of age who received high-dose melphalan as part of a conditioning regimen at the Winship Cancer Institute of Emory University between August 1, 2010 and April 1, 2020 and were followed through their transplant admission. After identification and inclusion of patients who received melphalan in combination with gabapentin or pregabalin, patient matching based on age (±5years), sex, and melphalan dose (140mg/m2 or 200mg/m2 ) was utilized to generate a comparable cohort of patients who received melphalan alone. The primary outcome was hospital length of stay (LOS); secondary outcomes included supportive care requirements between days +4 and day +14 and time to neutrophil and platelet-20 engraftment. Among 176 patients evaluated in each group, median hospital LOS was 16days, median time to neutrophil engraftment was 14days, and median time to platelet-20 engraftment was 16days in both groups. In addition, there were no significant differences in supportive care requirements between groups. In this study, use of gabapentin or pregabalin in combination with melphalan did not impact safety of the conditioning regimen in patients undergoing ASCT.

Long-term follow-up of patients with poor-risk acute leukemia treated on a phase 2 trial undergoing intensified conditioning regimen prior to allogeneic hematopoietic cell transplantation

Patients with acute leukemia who undergo allogenic hematopoietic cell transplantation with active disease have high rates of relapse and poor overall survival (OS) post-transplant compared to patients undergoing HCT in remission. Here, we report the long-term outcomes in 32 patients who received a high-intensity conditioning regimen comprising fractionated total body irradiation (FTBI; 1200 cGy) with pharmacokinetic (PK) dosing of intravenous Busulfan (IV BU) targeted to first dose area under curve (AUC) of 700–900 µM/min and etoposide (30 mg/kg) in a prospective phase 2 clinical trial. The median age of the patients at the time of HCT was 37 years (range: 18–50) presenting with high-risk (n = 6) and relapsed/refractory(r/r) acute leukemias (n = 26). All but one patient underwent HCT using peripheral blood stem cells from matched sibling donors. At a median follow-up of 17.3 years (range 14.4–19.0), 11 patients remained alive. The disease-free survival and OS at 15 years was 34% (versus 40% at 5-years post-HCT). The 15-year cumulative incidence of relapse was 26% and non-relapse mortality (NRM) was 38% (95% CI: 21–54%) and the cumulative incidence of chronic GVHD at 15 years was 33% using a prophylactic regimen of cyclosporine A and mycophenolate mofetil. The most common life-threatening late effects were secondary malignancies, metabolic, or cardiac complications with a cumulative incidence of 6.6%, 6.6%, and 13.3%, respectively. No unusual late effects or patterns of relapse were noted on longer followed on patients treated with intensified myeloablative condition regimen. Results from this study supports continued development of intensive conditioning regimens in patients with r/r acute leukemias to improve leukemia free (LFS) and OS in this high-risk population.