Nonmyeloablative Transplantation Research Articles

Azathioprine/hydroxyurea preconditioning prior to nonmyeloablative matched sibling donor hematopoietic stem cell transplantation in adults with sickle cell disease: A prospective observational cohort study.

Nonmyeloablative, matched sibling donor hematopoietic stem cell transplantation with alemtuzumab/total body irradiation (TBI) conditioning is a curative therapy with low toxicity for adults with sickle cell disease (SCD). However, relatively low donor chimerism levels and graft rejection remain important challenges. We hypothesized that adding azathioprine/hydroxyurea preconditioning will improve donor chimerism levels and reduce graft failure rate. In this prospective cohort study, we enrolled consecutive adult patients with SCD undergoing matched sibling donor transplantation at the Amsterdam UMC. Patients received azathioprine 150 mg/day and hydroxyurea 25 mg/kg/day for 3 months prior to alemtuzumab 1 mg/kg and 300 cGy TBI conditioning. Twenty patients with SCD (median age 26 years [range 19-49], 13 females) were transplanted. Median follow-up was 46.0 months (IQR 21.8-57.9). One-year overall survival and event-free survival (graft failure or death) were both 95% (95% confidence interval 86-100). Mean donor myeloid and T-cell chimerism 1-year post-transplant were 95.2% (SD ±10.6) and 67.3% (±15.3), respectively. One patient (5%) experienced graft failure without autologous regeneration, resulting in infections and death. All other patients had a corrected SCD phenotype and were able to discontinue sirolimus. Three patients were successfully treated with alemtuzumab (1 mg/kg) after the transplant because of declining donor chimerism and cytopenias to revert impending graft rejection. Toxicity was mostly related to sirolimus and alemtuzumab. One patient developed steroid-responsive grade II intestinal acute graft-versus-host disease. Collectively, preconditioning with azathioprine/hydroxyurea prior to nonmyeloablative matched sibling donor transplantation resulted in excellent event-free survival and robust donor T-cell chimerism, enabling the successful withdrawal of sirolimus. ClinicalTrials.gov: NCT05249452.

Graft Failure Incidence, Risk Factors, and Outcomes in Patients Undergoing Non-Myeloablative Allogeneic Hematopoietic Cell Transplantation Using Post-Transplant Cyclophosphamide

Graft failure (GF) is a major complication of allogeneic hematopoietic cell transplantation (alloHCT) that results in significant morbidity and mortality. Post-transplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis has emerged as an effective regimen across the spectrum of donor-match settings, but few studies have investigated the characteristics of GF in the setting of PTCy-based GVHD prophylaxis. The objective was to detail the incidence, clinical features, risk factors, and outcomes for patients with primary graft failure (PGF) and secondary graft failure (SGF). In this retrospective study at a single institution, 958 consecutive patients undergoing first nonmyeloablative (NMA) alloHCT with PTCy-based GVHD prophylaxis were analyzed. PGF was defined as a failure to achieve an ANC ≥ 500 cells/m3 by day 30 of transplant in the absence of residual disease. SGF was defined as complete loss of donor chimerism after initial engraftment. The incidences of PGF and SGF were 3.8% (n = 37) and 1.8% (n = 17), respectively. Neither PGF nor SGF were associated with HLA disparity. In a multivariate analysis, risk factors for PGF in this cohort included age ≥ 65 (OR 2.4, 95% CI 1.2 to 4.8, P = .0120), an underlying diagnosis of MDS, MPN, or MDS/MPN overlap (OR 2.8, 95% CI 1.4 to 5.7, P = .0050), post-transplant viremia with HHV-6 (OR 2.9, 95% CI 1.5 to 5.7, P = .0030), and low CD34+ dose (OR 0.7, 95% CI 0.5 to 0.9, P = .0080). Patients with PGF had poor overall survival, driven primarily by a high rate of nonrelapse mortality (59% at 36 months). SGF was associated with use of a bone marrow graft source and a diagnosis of Hodgkin lymphoma. Patients with SGF had excellent clinical outcomes with only one of seventeen patients experiencing relapse and relapse-related mortality. The incidence of PGF and SGF in patients receiving NMA conditioning and PTCy is low and is not impacted by HLA disparities between donors and recipients. PGF is more common in recipients with age ≥ 65, a diagnosis of MDS, MPN, or MDS/MPN-overlap, post-transplant HHV-6 viremia, and low CD34+ cell dose. Low total nucleated cell dose is also a risk factor for PGF in patients receiving a bone marrow graft source. Patients who experience PGF have poor outcomes due to high rates of nonrelapse mortality, whereas patients who experience SGF have excellent long-term outcomes.

Favorable outcome of non-myeloablative allogeneic transplantation in adult patients with severe sickle cell disease: A single center experience of 200 patients.

Allogeneic hematopoietic stem cell transplant (HSCT) for adults with severe sickle cell disease (SCD) is potentially curative but not commonly utilized therapy due to complications such as graft failure (GF) and organ toxicity. Herein, we are reporting our long-term outcome data of non-myeloablative (NMA) HSCT in adults with severe SCD with emphasis on factors predicting event free survival (EFS). Adults with severe SCD undergoing NMA match-related donor allogeneic HSCT from 2015 to 2021 with at least 12 months of follow-up were included. A total of 200 patients were included with a median age of 26 years (14-43) and 56% were male. The median infused CD34 dose was 13.7 (5.07-25.8), respectively. Median absolute neutrophil count engraftment was 19 (13-39) days with 51% of patients receiving GCSF to expedite recovery. A total of 17 patients experienced GF; 3 as primary and 14 as secondary within a median time of 204 days (40-905). A 76% successfully discontinued sirolimus at the last follow-up. Median follow-up for the cohort is 29.2 (2.1-71.4) months. Estimated 3-year EFS and OS were 88.2% (81.9-92.5) and 94.6% (89.2-97.3). At multivariable analysis, minor ABC incompatibility hazard ratio (HR) 4 (1.3-12.1; 0.014) and allo-antibody against non-ABO donor antigens HR 4.3 (1.3-14.1; 0.016) were significant for EFS. No clonal evolution or myeloid malignancies were seen. This largest single-center report of NMA HSCT in adults with severe SCD further delineated its feasibility, potential toxicities, and fertility outcomes. GF remains a major impediment and appears dependent on ABO matching and non-ABO antibodies.

Establishment of acute graft-versus-host disease model after non-myeloablative haploidentical peripheral blood stem cell transplantation in aged mice

Objective: To establish an acute graft-versus-host disease (aGVHD) model in aged mice after non-myeloablative haploidentical peripheral blood stem cell transplantation (haplo-PSCT). Methods: C57BL/6 (H-2b) male mice aged 6-8 weeks were used as donor mice, and CB6F1 (H-2b×d) female mice aged 14-16 months were used as recipient mice. The donor mice were injected subcutaneously with rehuman granulocyte-colony stimulating factor (rhG-CSF) 5 days before transplantation for hematopoietic stem cell mobilization.The recipient mice were divided into control group (CG), spleen cell low-dose group (SL), spleen cell medium-dose group (SM) and spleen cell high-dose group (SH) according to random number table method, with 16 rats in each group, all of which received total linear accelerator X-ray irradiation (TBI) with a total dose of 6 Gy. Peripheral blood mononuclear cells (PBMC) and spleen cells of different doses (0.5×107/each, 1.0×107/each and 2.0×107/each in SL group, SM group and SH group, respectively) were transfused through the tail vein within 4 hours after TBI, and only the same amount of normal saline was transfused in CG group. After transplantation, the survival and weight changes of mice in each group were observed for 30 days, and the changes of blood routine were monitored regularly. Mice peripheral blood was collected 21 days after transplantation to detect the chimerism rate of the donor. Hematoxylin-eosin staining was performed on the skin, liver and colon of mice 21 days after transplantation to analyze the histopathological changes of aGVHD target organs. Results: All the mice in each group were successfully transplanted. After TBI, the weight and activity of mice in all groups decreased, and the phenomenon of bone marrow suppression appeared. During the observation period, all mice in CG group and SL group survived, 3 mice in SM group died with survival time of (26.0±5.8) days, and 6 mice in SH group died with survival time of (20.9±7.3) days. The body weight of mice in SH group was lower than that in CG group, SL group and SM group 21days after transplantation [(25.0±0.7), (25.5±0.4), (25.0±1.4) vs (20.8±0.8) g, all P<0.05]. Compared with CG group, SL group and SM group, the levels of leukocyte, erythrocyte, hemoglobin and platelet in SH group decreased 21 days after transplantation (all P<0.05). There was no significant difference in donor chimerism rate among SL group, SM group and SH group [(95.8%±0.8%), (95.5%±1.4%) and (95.1%±1.3%), respectively, all P>0.05]. Compared with CG group, SL group and SM group, the tissue structure of aGVHD target organs in SH group was severely damaged, with a large number of inflammatory cells infiltratedand higher histopathological scores than SL group and SM group (all P<0.05). Conclusion: For aging CB6F1 mice, after 6 Gy TBI pretreatment with linear accelerator X-ray, PBMC (1×107/each) and spleen cells (2.0×107/each) were injected to successfully induce aGVHD model after non-myelablative haplo-PSCT.

Post-Transplant Maintenance in AML and MDS Patients Undergoing Non-Myeloablative Peripheral Blood Stem Cell Transplant with Post-Transplant Cyclophosphamide

Post-Transplant Maintenance in AML and MDS Patients Undergoing Non-Myeloablative Peripheral Blood Stem Cell Transplant with Post-Transplant Cyclophosphamide

Efficacy and Prognostic Factors of Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Acute Myeloid Leukemia

To retrospectively analyze the efficacy and complications of our institution's modified nonmyeloablative allogeneic hematopoietic stem cell transplantation (NST) in treating intermediate-risk acute myeloid leukemia (AML) - first complete remission (CR1) and prognostic factors. Clinical data of 50 intermediate-risk AML-CR1 patients who underwent matched related NST at the Fifth Medical Center of Chinese People's Liberation Army General Hospital from August 2004 to April 2021 were collected, the hematopoietic recovery, donor engraftment and complications were observed, and overall survival (OS) rate, leukemia-free survival (LFS) rate, treatment-related mortality (TRM), and cumulative relapse rate were calculated. Statistical analysis of factors affecting prognosis was also preformed. The median times for neutrophil and platelet recovery after transplantation were 10 (6-16) and 13 (6-33) days, respectively. One month after transplantation, 22 patients (44%) achieved full donor chimerism (FDC), and 22 patients (44%) achieved mixed chimerism (MC), among whom 18 cases gradually transited to FDC during 1-11 months, 4 cases maintained MC status. The overall incidence of acute graft-versus-host disease (aGVHD) was 36%, with a rate of 18% for grade II-IV aGVHD and a median onset time of 45 (20-70) days after transplantation. The overall incidence of chronic GVHD (cGVHD) was 34%, with 20% and 14% of patients having limited or extensive cGVHD, respectively. The incidence rates of infections, interstitial pneumonia, and hemorrhagic cystitis were 30%, 10%, and 16%, respectively. The 5-year OS rate, LFS rate, TRM, and cumulative relapse rate were 68%, 64%, 16%, and 20%, respectively. The increase of the number of CD34+ cells infused had shortened the recovery time for neutrophils and platelets (r =0.563, r =0.350). The number of CD34+ cells infused significantly influenced the occurrence of extensive cGVHD (OR =1.36, 95%CI : 1.06-1.84, P =0.024). Modified NST is effective in treating intermediate-risk AML-CR1 patients, however, further expansion of sample size is needed to study prognostic factors.

SCD Dyslipidemia Normalizes Long-Term Following Nonmyeloablative Hematopoietic Cell Transplantation

Dyslipidemia is common in patients with sickle cell disease (SCD). Individuals with SCD have a unique type of dyslipidemia. This SCD dyslipidemia (hypocholesterolemia subtype) is characterized by low total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c), and normal triglycerides (TG). This SCD dyslipidemia state is theorized to be cardioprotective regarding atherosclerotic risk due to the hypolipidemic condition. Hematopoietic cell transplantation (HCT) is a potentially curative therapy for SCD. Nonmyeloablative HCT has been employed at the National Institutes of Health (NIH) and internationally with good results. Long-term survivors of HCT, specifically for hematologic malignancies, are at increased risk for dyslipidemia (hypercholesterolemia subtype), thus increasing atherosclerotic risk long-term. There are no studies investigating the short or long-term effects of HCT on SCD dyslipidemia. Therefore, we report a novel study to characterize lipid profiles at baseline and after HCT for SCD. This cohort study analyzes data from patients who received their first nonmyeloablative HLA-matched sibling or haploidentical HCT for SCD at the NIH from May 2009 to December 2021. All patients received sirolimus as GVHD prophylaxis. Total cholesterol, HDL-c, LDL-c, and triglycerides were collected pre-HCT, one-year post-HCT, and annually thereafter via a fasting serum-based lipid panel (median follow-up of 4 years). Data were analyzed using linear generalized estimating equation regression models to measure the influence of factors such as year of HCT, sirolimus use, gender, age, and graft failure on TC, LDL-c, HDL-c, and TG levels. A total of 116 patients were included in this analysis. There were 72 male and 44 female patients. The median age was 31 (range 10 to 64) years. 90% of the patients had Hb-SS, 3% Hb-SC, 5% Hb-Sβ 0, and 2% Hb-Sβ +. Overall survival is 87%, and 19% experienced graft failure. The median time on sirolimus post-HCT was one year. Baseline, one-year, and two-year mean (25th, 75th percentile) values, respectively, for the TC, LDL-c, HDL-c, and TG are as follows: TC [130.7 (107.0, 147.0), 183.2 (144.5, 220.0), 175.2 (144.5, 209.0)], LDL-c [72.5 (50.0, 87.0), 109 (73.5, 130), 104.2 (75.5, 128.0)], HDL-c [32.3 (23.8, 39.3), 49.4 (38.0, 55.5), 49.2 (41.5, 58.0)] and TG [127.3 (88.5, 156.5), 125.9 (87.0, 153.5), 112.6 (72.0, 133.5)]. Generally, the first-year post-HCT changes were maintained annually thereafter. (Figure 1). According to linear regression modeling, the change in TC, LDL-c, HDL-c, and TG at one-year post-HCT was +50.3 mg/dL (p&amp;lt;0.0001), +36.4 mg/dL (p &amp;lt;0.0001), +20.4 mg/dL (p&amp;lt;0.0001) and -26.5 mg/dL (p&amp;lt;0.0001), respectively. For failed grafts, the estimated changes after one-year post-HCT in TC, LDL-c, HDL-c, and TG were +6.5 mg/dL (p=0.45), -2.1 mg/dL (p=0.78), +14.8 mg/dL (p&amp;lt;0.0001), and -28.0 (p=0.03), respectively. The use of sirolimus only resulted in a significant change in TG (+32.8 mg/dL (p = 0.004)). Age had statistically significant changes only on TC (+1.08 mg/dL for a one-year change in age, p=0.005) and LDL-c (+0.73 mg/dL for a one-year change in age, p=0.03). There were no significant differences in TC, LDL-c, HDL-c, and TG levels (p&amp;gt;0.05) based on gender and HCT type. To summarize, HCT with sustained grafts led to significant rises in TC, LDL-c, and HDL-c and a decline in TG from baseline to one-year post-HCT, resulting in the normalization of lipid profiles. These changes were maintained annually thereafter. Graft failure most notably resulted in TC and LDL-c level declines back to pre-HCT baseline (Figure 2), while HDL-c and TG levels did not completely revert to baseline values. Sirolimus effects were significant on TG levels alone. These findings suggest that the mechanism underlying SCD dyslipidemia is corrected with the reversal of SCD. Long-term follow-up studies are indicated to assess patients' risk for atherosclerosis and adverse cardiac outcomes.

Post-Transplant Maintenance in AML and MDS Patients Undergoing Non-Myeloablative Peripheral Blood Stem Cell Transplant with Post-Transplant Cyclophosphamide

Disease relapse remains a major cause of mortality for patients with AML and MDS undergoing allogeneic hematopoietic stem cell transplant (HSCT). Several trials have evaluated the use of hypomethylating agents (HMA) like azacitadine or decitabine as post-transplant maintenance with its use not currently recommended. Here we review our experience with AML and MDS patients undergoing non-myeloablative (NMA) peripheral blood stem cell transplant using post-transplant cyclophosphamide (PTCy) as GVHD prophylaxis and in whom post-transplant maintenance was used. We retrospectively reviewed AML and MDS patients who had a NMA HSCT from January 2015 until December 2022. All patients received fludarabine, cyclophosphamide and TBI200 or TBI300 as conditioning regimen with tacrolimus, mycophenolate mofetil and PTCy as GVHD prophylaxis (Table 1). Sixty patients received TBI200 and 28 patients received TBI300. Median age at transplant was 65.5 years in the TBI200 group vs 69 years in the TBI300 group. Haploidentical donors were used in 59 (98%) of patients in the TBI200 group and 18 (64%) of patients in the TBI300 group. Minimal residual disease (MRD) was present 35 (58%) of patients receiving TBI200 and 12 (43%) of patients receiving TBI300. Post-transplant therapy was given in 46 (77%) of patients in the TBI200 group and 23 (82%) in the TBI300 group. The majority of patients in both groups received azacitadine. The median cycles of HMAs was 4 (range 1-12). We found no difference in OS, PFS, relapse, or NRM comparing Flu/Cy/TBI200 and Flu/Cy/TBI300 (not shown). We evaluated the use of post-transplant maintenance on survival endpoints and found no difference in endpoints. In addition, post-transplant maintenance had no effect on OS, PFS, relapse, NRM or grade II-IV aGVHD regardless of MRD status at time of transplant. While, this is a small retrospective series, it warrants further investigation into the use of post-transplant maintenance in the setting of NMA HSCT using PTCy. While the use of HMA's did not increase NRM, their efficacy and perhaps combination with other drugs needs to be more closely studied in NMA PTCy transplants to decrease relapse.

Low Disease Relapse and High Survival in Non-Myeloablative Two-Step Haploidentical Transplant, Results of a Prospective Trial

Introduction We previously developed a two-step approach that separates the lymphoid and myeloid portions of the graft, allowing a consistent T cell dosing and sparing the stem cells from the effect of cyclophosphamide. The two-step approach demonstrated safety and efficacy in patients treated with a myeloablative conditioning protocol. Here, we extended our 2-step platform to older and less fit patients and explored the effects of using a high dose of T cells on disease relapse and transplant outcomes. Methods Patients received fludarabine 30mg/m 2 IV daily for 3 days, from day -10 to day -8. Two hundred cGy total body irradiation (TBI) was given on day -7. This was increased to 400 cGy TBI in 2 doses after 13 patients had been treated. A fixed dose of 2 x 10 8/kg CD3+ T cells was given on day -6, followed 2 days later by cyclophosphamide 60mg/kg IV daily on day -3 and day -2. Tacrolimus and mycophenolic acid were started on day -1, followed by infusion of CD34-selected stem cells on day 0. Results Thirty-three patients with hematologic malignancies were treated (Table 1). Majority were haploidentical transplants (91%), and the rest were matched related donors. Median age was 68 (range, 33-76) years, with 64% patients &amp;gt;65 years old. Median follow-up was 31 months (range, 0-76 months). Median HCT-comorbidity score was 4 (range, 0-9). Forty-seven percent had high or very high-risk disease risk index. Twenty-seven percent had prior autologous transplant. Overall survival was 75% at 1 year and 50% at 3 years. The cumulative incidence (CI) of non-relapse mortality (NRM) and relapse were 22% and 31% at 3 years. However, the CI of relapse was much lower for patients treated with 400 cGy TBI versus those treated with 200 cGy TBI (6% vs 54%, p = 0.017) (Figure 1), while NRM was similar (25% vs 15%, p = 0.348). This contributed to a very high survival of 69% in patients who received the higher dose of TBI at 3 years, with median OS not reached. The median time to neutrophil and platelet recovery was 11 and 17 days, respectively. The median donor CD3+ T cell chimerism at day +28 was 100% (range, 71% to 100%). The CI of grade II acute graft-versus-host-disease (GVHD) was 23% and 27% at 100 days and 6 months, respectively. The CI of chronic GVHD was 8% at 3 years. There were no grade III or IV acute GVHD, no severe chronic GVHD and no deaths attributable to acute or chronic GVHD. There were 13 deaths in the study, of which 7 died from disease relapse, 3 died from toxicity related to treatment regimen, and 2 died from infection. Conclusions The NMA two-step approach allo-SCT showed a low disease relapse rate and high survival in patients treated with 400 cGy TBI, despite a generally older and more medically compromised patient population.

Follow-up analysis of sex hormone levels and prognosis in women after hematopoietic stem cell transplantation

Objective: To investigate the levels of sex hormone and fertility in female patients after hematopoietic stem cell transplantation (HSCT), as well as their correlation with conditioning regimens, and analyse the effect of hormone replacement therapy (HRT) in young women after HSCT. Methods: Retrospective case series study. The clinical data of 147 women who underwent HSCT in the First Affiliated Hospital of Soochow University from January 2010 to January 2021 were retrospectively analyzed. The sex hormone levels were measured and followed-up, and the survival, menstrual fertility and the use of HRT of the patients were also followed-up. The sex hormone levels were measured after transplantation, and the ovarian function was evaluated. Independent sample t test and χ2 test were used for comparison between the two groups. Results: The median age of the 147 patients was 26 (range, 10-45) years. Of them, 135 patients received allogeneic HSCT and 12 patients received autologous HSCT. Furthermore, 129 patients received myeloablative conditioning, and 18 patients received reduced conditioning dose. The median follow-up time was 50 months (range, 18-134 months). Five patients died of disease recurrence during follow-up. Of the 54 patients with subcutaneous injection of zoladex, three recovered menstruation spontaneously after transplantation, and all of them were myeloablative conditioning patients, one patient gave birth to twins through assisted reproductive technology. Ninety-three patients did not use zoladex before conditioning, two patients with aplastic anemia with non-myeloablative transplantation resumed menstruation spontaneously, and conceived naturally. The level of follicle stimulating hormone after transplantation in patients receiving myeloablative conditioning regimen was significantly higher than that in patients receiving reduced-dose conditioning regimen [(95.28±3.94) U/L vs. (71.85±10.72) U/L, P=0.039]. Among 147 patients, 122 patients developed premature ovarian failure, 83 patients received sex hormone replacement therapy after transplantation, and 76 patients recovered menstruation and improved endocrine function. Conclusions: The incidence of premature ovarian failure is high in female patients after HSCT, and patients have a chance at natural conception. Reducing the dose of conditioning regimen and the application of zoladex before transplantation can reduce ovarian of conditioning drugs. HRT after transplantation can partially improve the endocrine function of patients.

Thyroid and Adrenal Dysfunction in Hemoglobinopathies Before and After Allogeneic Hematopoietic Cell Transplant.

To determine the rate and clinical characteristics associated with abnormal thyroid and adrenal function in recipients of nonmyeloablative hematopoietic cell transplantation (HCT) for sickle cell disease (SCD) and beta-thalassemia. We retrospectively reviewed patients who enrolled in 4 nonmyeloablative HCT regimens with alemtuzumab and total body irradiation (TBI). Baseline and annual post-HCT data were compared, which included age, sex, sickle phenotype, thyroid panel (total T3, free T4, thyroid stimulating hormone, antithyroid antibodies), cortisol level, ACTH stimulation testing, ferritin, medications, and other relevant medical history. Among 43 patients in haploidentical transplant and 84 patients in the matched related donor protocols with mostly SCD, the rate of any thyroid disorder pre-HCT was 3.1% (all subclinical hypothyroidism) and post-HCT was 29% (10 hypothyroidism, 4 Grave's disease, and 22 subclinical hypothyroidism). Ninety-two (72%) patients had ferritin >1000 ng/dL, of which 33 patients (35.8%) had thyroid dysfunction. Iron overload was noted in 6 of 10 patients with hypothyroidism and 12 of 22 patients with subclinical hypothyroidism.Sixty-one percent were on narcotics for pain control. With respect to adrenal insufficiency (AI) pre-HCT, 2 patients were maintained on corticosteroids for underlying rheumatologic disorder and 8 had AI diagnosed during pre-HCT ACTH stimulation testing (total 10, 7.9%). Post-HCT, an additional 4 (3%) developed AI from corticosteroid use for acute graft vs host disease, Evans syndrome, or hemolytic anemia. Although iron overload was common in SCD, thyroid dysfunction pre-HCT related to excess iron was less common. Exposure to alemtuzumab or TBI increased the rates of thyroid dysfunction post-HCT. In contrast, AI was more common pre-HCT, but no risk factor was identified. AI post-HCT was infrequent and associated with corticosteroid use for HCT-related complications.

Post-Transplant Cyclophosphamide for the Prevention of Graft-vs.-Host Disease in Allogeneic Hematopoietic Cell Transplantation: A Guide to Management for the Advanced Practitioner.

Cyclophosphamide remains a critical component to haploidentical transplant conditioning regimens. Post-transplant cyclophosphamide (PTCy) emerged as an effective component of graft-vs.-host disease (GVHD) prophylaxis in the nonmyeloablative haploidentical bone marrow transplant setting. The relative ease of administration compared with ex vivo manipulations and efficacy in reducing GVHD has led to increasing PTCy use in transplant centers around the world. The role of PTCy has expanded to haploidentical transplantation with myeloablative conditioning regimens and peripheral blood progenitor cells as the donor source. Moreover, encouraging results in GVHD management have been shown with the use of PTCy alone or in combination with other immunosuppressives in the human leukocyte antigen-matched donor setting. The toxicity profile of cyclophosphamide varies extensively depending on dose, duration, overall drug exposure, and, potentially, pharmacogenetics. This review highlights the pharmacology, pharmacokinetics, and toxic effects of cyclophosphamide and offers practical guidance for clinical application in the post-transplant setting. We summarize data on the management of high-dose cyclophosphamide toxicities and provide insights into the pharmacogenetic implications on drug efficacy and safety data.

O-151 - Non-myeloablative allogeneic stem cell transplantation using TSEBT, TLI and ATG for mycosis fungoides and Sézary syndrome: results from a large single centre cohort

O-151 - Non-myeloablative allogeneic stem cell transplantation using TSEBT, TLI and ATG for mycosis fungoides and Sézary syndrome: results from a large single centre cohort

A multimodal interdisciplinary rehabilitation programme (HAPPY) for patients undergoing allogeneic non-myeloablative haematopoietic stem cell transplantation: A feasibility study.

To evaluate the feasibility of the multimodal interdisciplinary rehabilitation programme HAPPY, targeting patients with haematological malignancy and undergoing allogeneic non-myeloablative haematopoietic stem cell transplantation (NMA-HSCT). A single arm longitudinal design was applied to test the feasibility of the 6-month HAPPY programme, which consisted of motivational interviewing dialogues, individual supervised physical exercise training, relaxation exercises, nutritional counselling, and home assignments. The feasibility measures included acceptability, fidelity, exposure, practicability, and safety. Descriptive statistics were conducted. From November 2018 to January 2020, thirty patients (mean age (SD) 64.1 (6.5)) were enrolled in HAPPY, of whom 18 patients completed the programme. Acceptance was 88%; attrition 40%; fidelity was 80%-100% for all HAPPY elements except phone calls; exposure of HAPPY elements at the hospital reflected individual differences but was acceptable, whereas exposure of HAPPY elements at home was low. Planning of HAPPY for the individual patient was time consuming, and patients were dependent of reminders and incites from the health care professionals. Most elements of the rehabilitation programme HAPPY were feasible. Yet, HAPPY will benefit from further development and simplifications before an effectiveness study can be conducted, especially regarding improvement of the intervention elements supporting patients at home.

Triple-Drug Graft-versus-Host Disease Prophylaxis after HLA-Matched Unrelated Donor Nonmyeloablative Allogenic Hematopoietic Stem Cell Transplantation

Adding sirolimus to graft-versus-host disease (GVHD) prophylaxis with cyclosporin and mycophenolate mofetil (MMF) reduced the risk of grade II-IV acute GVHD after nonmyeloablative (NMA) allogenic hematopoietic stem cell transplantation (HSCT) with an HLA-matched unrelated donor in a randomized clinical trial. We analyzed real-life data to investigate the impact of implementing the triple-drug regimen with cyclosporin, MMF and sirolimus as standard GVHD prophylaxis after NMA HSCT with an HLA-matched unrelated donor at our institution. We studied all adult patients (age ≥18 years) who underwent NMA HSCT with an HLA-matched unrelated donor at Rigshospitalet, Copenhagen University Hospital, Denmark between 2018 and 2021 and received GVHD prophylaxis with cyclosporin, MMF and sirolimus (triple-drug group [TDG]). Comparisons were made with a historical cohort who received tacrolimus and MMF as GVHD prophylaxis after HLA-matched unrelated donor NMA HSCT between 2014 and 2017 (control group [CG]). Outcomes were grade II-IV and grade III-IV acute GVHD, chronic GVHD, relapse, nonrelapse mortality (NRM) andoverall survival (OS). A total of 264 patients were included (TDG, n = 137; CG, n = 127). Median age was 66 years (interquartile range [IQR], 58 to 69 years) in the TDG and 63 years (IQR, 57 to 68 years) in the CG. Acute myeloid leukemia and myelodysplastic syndrome were the most frequent indications for HSCT in both groups (TDG, 33% and 23%, respectively; CG, 36% and 22%, respectively). The cumulative incidence at day +110 of grade II-IV GVHD was 17% (95% confidence interval [CI] 11% to 23%) in the TDG versus 29% (95% CI, 21% to 37%) in the CG (P = .02, Gray's test) and that of grade III-IV acute GVHD was 3% (95% CI, 0 to 6%) versus 5% (95% CI, 1% to 8%), respectively (P = .4, Gray's test). In a Cox regression model adjusted for age, donor age and female donor to male recipient the risk of grade II-IV acute GVHD was lower in the TDG compared to the CG (hazard ratio [HR], .51; 95% CI .30 to .86; P = .01). The 2-year OS was 77% (95% CI, 70% to 84%) in the TDG and 69% (95% CI, 61% to 77%) in the CG (P = .04), and this difference remained significant after adjustment for age and Karnofsky Performance Status (HR, .65; 95% CI, .42 to .99; P = .04). The 2-year cumulative incidences of chronic GVHD, relapse and NRM were 60% (95% CI, 51% to 69%), 21% (95% CI, 13% to 28%), and 12% (95% CI, 6% to 17%), respectively, in the TDG and 62% (95% CI, 54% to 71%), 27% (95% CI, 19% to 35%) and 14% (95% CI, 8% to 20%), respectively, in the CG. Multivariable analyses revealed no difference in the risk of chronic GVHD (HR, .91; 95% CI, .65 to 1.26; P = .56), relapse (HR, .70; 95% CI, .42 to 1.15; P = .16) or NRM (HR, .56; 95% CI, .31 to 1.05; P = .07). After changing the standard GVHD prophylaxis in patients undergoing NMA HSCT with an HLA-matched unrelated donor from tacrolimus and MMF to cyclosporin, MMF and sirolimus, we observed a reduction in the incidence of grade II-IV acute GVHD and improved 2-year OS.

Accumulation of Dystrophin-Positive Muscle Fibers and Improvement of Neuromuscular Junctions in mdx Mouse Muscles after Bone Marrow Transplantation under Different Conditions.

Duchenne muscular dystrophy (DMD) is a severe muscular disorder caused by mutations in the dystrophin gene. It leads to respiratory and cardiac failure and premature death at a young age. Although recent studies have greatly deepened the understanding of the primary and secondary pathogenetic mechanisms of DMD, an effective treatment remains elusive. In recent decades, stem cells have emerged as a novel therapeutic product for a variety of diseases. In this study, we investigated nonmyeloablative bone marrow cell (BMC) transplantation as a method of cell therapy for DMD in an mdx mouse model. By using BMC transplantation from GFP-positive mice, we confirmed that BMCs participate in the muscle restoration of mdx mice. We analyzed both syngeneic and allogeneic BMC transplantation under different conditions. Our data indicated that 3 Gy X-ray irradiation with subsequent BMC transplantation improved dystrophin synthesis and the structure of striated muscle fibers (SMFs) in mdx mice as well as decreasing the death rate of SMFs. In addition, we observed the normalization of neuromuscular junctions (NMJs) in mdx mice after nonmyeloablative BMC transplantation. In conclusion, we demonstrated that nonmyeloablative BMC transplantation could be considered a method for DMD treatment.

Human Hematopoietic Stem/Progenitor Cells in Type One Diabetes Mellitus Treatment: Is There an Ideal Candidate?

Type 1 diabetes mellitus (T1DM) is a highly prevalent autoimmune disease causing the destruction of pancreatic islet β-cells. The resulting insulin production deficiency leads to a lifelong need for insulin re-placement therapy, systemic complications, and reduced life quality and expectancy. Cell therapy has been extensively attempted to restore insulin independence (IID), and autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) has appeared to give the most promising results, but with a highly variable quote of patients achieving IID across the studies. We performed a comprehensive review of the trials involving stem cells, and in particular AHST, for the treatment of T1DM. We then pooled the patients enrolled in the different trials and looked for the patient characteristics that could be associated with the achievement of IID. We found a significantly higher probability of achieving IID in older patients (OR 1.17, 95%CI 1.06-1.33, p = 0.002) and a significantly lower probability in patients with a history of ketoacidosis (OR 0.23, 95%CI 0.06-0.78, p = 0.023). This suggests that there could be a population of patients more likely to benefit from AHST, but further data would be required to depict the profile of the ideal candidate.

74 - Interleukin-6 (IL-6) Continuous Infusion Adversely Affects Engraftment in a Non-Myeloablative Transplant Murine Model

74 - Interleukin-6 (IL-6) Continuous Infusion Adversely Affects Engraftment in a Non-Myeloablative Transplant Murine Model

How does autologous non-myeloablative selective hematopoietic stem cell transplantation (HSCT) compare with cyclophosphamide in adults with systemic sclerosis?

How does autologous non-myeloablative selective hematopoietic stem cell transplantation (HSCT) compare with cyclophosphamide in adults with systemic sclerosis?

Anti-Thymocyte Globulin (ATG)-Free Nonmyeloablative Haploidentical PBSCT Plus Post-Transplantation Cyclophosphamide Is a Safe and Efficient Treatment Approach for Pediatric Acquired Aplastic Anemia

Most cases of acquired aplastic anemia (AA) arise from autoimmune destruction of hematopoietic stem and progenitor cells. Human leukocyte antigen (HLA)-haploidentical nonmyeloablative hematopoietic stem cell transplantation (HSCT) plus post-transplantation cyclophosphamide (PTCy) is increasingly applied to salvage AA using bone marrow as graft and anti-thymocyte globulin (ATG) in conditioning. Herein, we characterize a cohort of twelve AA patients clinically and molecularly, six who possessed other immunological disorders (including two also carrying germline SAMD9L mutations). Each patient with SAMD9L mutation also carried an AA-related rare BCORL1 variant or CTLA4 p.T17A GG genotype, respectively, and both presented short telomere lengths. Six of the ten patients analyzed harbored AA-risky HLA polymorphisms. All patients recovered upon non-HSCT (n = 4) or HSCT (n = 8) treatments. Six of the eight HSCT-treated patients were subjected to a modified PTCy-based regimen involving freshly prepared peripheral blood stem cells (PBSC) as graft and exclusion of ATG. All patients were engrafted between post-transplantation days +13 and +18 and quickly reverted to normal life, displaying a sustained complete hematologic response and an absence of graft-versus-host disease. These outcomes indicate most AA cases, including of the SAMD9L-inherited subtype, are immune-mediated and the modified PTCy-based regimen we present is efficient and safe for salvage.