Unmanipulated haploidentical transplantation conditioning with busulfan, cyclophosphamide and anti-thymoglobulin for adult severe aplastic anaemia

Meta-analysis of the results of haploidentical transplantation in the treatment of aplastic anemia

This meta-analysis was to evaluate the outcome of haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) for aplastic anemia (AA) compared with matched related donor (MRD)-HSCT, matched unrelated donor (MUD)-HSCT, and immunosuppressive therapy (IST). Pubmed, Embase, Cochrane Library, Web of Science, CNKI, WanFang, and VIP databases were searched for relevant studies from inception to 22 June 2022. Relative risk (RR) was used to indicate the effect indicator, with a 95% confidence interval (CI) being applied to express the effect size. A subgroup analysis based on the literature quality (low, fair, and high) was applied. Totally, 25 studies were included in this study, comprising 2252 patients. Our findings demonstrated no difference between Haplo-HSCT and MRD-HSCT in 1-, 2-, and 3-year overall survival (OS), failure-free survival (FFS), and engraftment. However, Haplo-HSCT had higher incidences of II-IV acute graft-versus-host disease (aGVHD), chronic GVHD (cGVHD), and cytomegalovirus infection. There were no differences in 3- and 5-year OS, 3-year FFS, platelet engraftment, graft failure (GF), II-IV grade of aGVHD, and complication between Haplo-HSCT and MUD-HSCT; however, Haplo-HSCT had a lower incidence of cGVHD. Compared with IST, Haplo-HSCT had a higher 3-year FFS and 3- and 6-month response rate. However, there were no differences in 3- and 5-year OS, and 12-month response rate between Haplo-HSCT and IST. This study suggests that Haplo-HSCT may be a realistic therapeutic option for AA, which may provide a reference for decision-making.

Comparison of Haploidentical Hematopoietic Stem Cell Transplant With or Without Unrelated Cord Blood Infusion in Severe Aplastic Anemia: Outcomes of a Multicenter Study

The purpose of this study in severe aplastic anemia (SAA) patients was to compare the feasibility and efficacy of haploidentical hematological stem cell transplantation combined with a single unrelated cord blood (UCB) infusion (Haplo-cord-HSCT) or haplo-identical HSCT (Haplo-HSCT) alone. The five-year graft-versus-host disease (GVHD)-free or failure-free survival (GFFS) was similar between the two groups (72.4 ± 3.4% vs. 65.4 ± 5.2%, P = 0.178); however, the five-year overall survival (OS) was more favorable in the Haplo-cord-HSCT group than that in the Haplo-HSCT group (84.0 ± 2.8% vs. 72.6 ± 4.9%, P = 0.022), as was transplantation-related mortality (16.4% vs. 27.4%, P = 0.039). Multivariate analysis showed that Haplo-cord HSCT was the only independent determinant of increased OS (P = 0.013). Explorative subgroup analysis showed that only an Human leukocyte antigen-A (HLA-A) allele match between UCB and the recipient was a beneficial factor for GFFS in the Haplo-cord-HSCT group (P = 0.011). In the haplo-cord with an HLA-A match (n = 139) or mismatch (n = 32) or Haplo-HSCT groups, a haplo-cord HLA-A allele match was associated with lower I–IV and III–IV acute GVHD. The haplo-cord with an HLA-A match subgroup also had higher five-year OS than the Haplo-HSCT group (85.4 ± 3.0% vs. 72.6 ± 4.9%, P = 0.013), and higher five-year GFFS than the Haplo-cord HLA-A allele mismatch subgroup (76.2 ± 3.6% vs. 56.3 ± 8.8%, P = 0.011). These findings suggest that the coinfusion of a single UCB potentially improves survival of Haplo-HSCT in SAA patients and that an HLA-A allele-matched UCB is the preferred option.

Comparable Outcomes in Acquired Severe Aplastic Anemia Patients With Haploidentical Donor or Matched Related Donor Transplantation: A Retrospective Single-Center Experience

Clinical data of patients with severe aplastic anemia (SAA) were retrospectively analyzed to evaluate the outcomes of haploidentical hematopoietic stem cell transplantation (HID-HSCT) with matched related sibling hematopoietic stem cell transplantation (MSD-HSCT) in complications and survivals. Thirty consecutive patients were enrolled in the study with a median follow-up of 50 months (range 4, 141), and the median age of the patients was 21 years (range 3, 49). All the patients achieved myeloid engraftment in the two cohorts. The cumulative incidences of platelet engraftment were 95.5 and 100% in HID cohort and MSD cohort, respectively. The median time for neutrophil and platelet recovery was 11 (range 9, 19) and 15 (range 10, 25) days in HID cohort, and 12 (range 10, 19) and 14 (range 8, 25) days in MSD cohort. The cumulative incidences of grade II–IV and grade III–IV acute graft vs. host disease (aGvHD) in HID cohort and in MSD cohort were 18.9 vs. 14.3% (p = 0.77) and 10.5 vs. 0% (p = 0.42), respectively. The cumulative incidences of chronic graft vs. host disease (cGvHD) was 22.7% in HID cohort and 25.5% in MSD cohort (p = 0.868). The 5-year overall survival (OS) rates and 5-year failure-free survival (FFS) rates in HID cohort and MSD cohort were 85.1 vs. 87.5% (p = 0.858), 80.3 vs. 87.5% (p = 0.635), respectively. The median time to achieve engraftment, cumulative incidence of aGvHD and cGvHD, and the 5-year OS and FFS rates were not significantly different between the two cohorts. We suggest that HID-HSCT might be a safety and effective option for SAA patients without a matched donor.

Infusion of haploidentical hematopoietic stem cells combined with mesenchymal stem cells for treatment of severe aplastic anemia in adult patients yields curative effects

BACKGROUND AIMS

Despite the great advances in immunosuppressive therapy for severe aplastic anemia (SAA), most patients are not completely cured. Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been recommended as an alternative treatment in adult SAA patients. However, haplo-HSCT presents a higher incidence of graft failure and graft-versus-host disease (GVHD). The authors designed a combination of haplo-HSCT and umbilical cord-derived mesenchymal stem cells (UC-MSCs) for treatment of SAA in adult patients and evaluated its effects.

METHODS

Adult patients (≥18 years) with SAA (N = 25) were given HLA-haploidentical hematopoietic stem cells (HSCs) combined with UC-MSCs after a conditioning regimen consisting of busulfan, cyclophosphamide, fludarabine and anti-thymocyte globulin and intensive GVHD prophylaxis, including cyclosporine, basiliximab, mycophenolate mofetil and short-term methotrexate. Additionally, the effects of the protocol in adult SSA patients were compared with those observed in juvenile SAA patients (N = 75).

RESULTS

All patients achieved myeloid engraftment after haplo-HSCT at a median of 16.12 days (range, 11-26). The median time of platelet engraftment was 28.30 days (range, 13-143). The cumulative incidence of grade II acute GVHD (aGVHD) at day +100 was 32.00 ± 0.91%. No one had grade III-IV aGVHD at day +100. The cumulative incidence of total chronic GVHD was 28.00 ± 0.85%. The overall survival was 71.78 ± 9.05% at a median follow-up of 42.08 months (range, 2.67-104). Promisingly, the protocol yielded a similar curative effect in both young and adult SAA patients.

CONCLUSIONS

The authors' data suggest that co-transplantation of HLA-haploidentical HSCs and UC-MSCs may provide an effective and safe treatment for adult SAA.

Development and validation of a mortality predicting scoring system for severe aplastic anaemia patients receiving haploidentical allogeneic transplantation

Haploidentical allogeneic haematopoietic stem cell transplantation (haplo-HSCT) is a significant alternative treatment for severe aplastic anaemia (SAA). To improve this process by modifying the risk stratification system, we conducted a retrospective study using our database. 432 SAA patients who received haplo-HSCT between 2006 and 2020 were enrolled. These patients were divided into a training (n = 288) and a validation (n = 144) subset randomly. In the training cohort, longer time from diagnosis to transplantation, poorer Eastern Cooperative Oncology Group (ECOG) status and higher haematopoietic cell transplantation-specific comorbidity index (HCT-CI) score were independent risk factors for worse treatment-related mortality (TRM) in the final multivariable model. The haplo-HSCT scoring system was developed by these three parameters. Three-year TRM after haplo-HSCT were 6% [95% confidence interval (CI), 1-21%], 21% (95% CI, 7-40%), and 47% (95% CI, 20-70%) for the low-, intermediate-, and high-risk group, respectively (P < 0·0001). In the validation cohort, the haplo-HSCT scoring system also separated patients into three risk groups with increasing risk of TRM: intermediate-risk [hazard ratio (HR) 2·45, 95% CI, 0·92-6·53] and high-risk (HR 11·74, 95% CI, 3·07-44·89) compared with the low-risk group (P = 0·001). In conclusion, the haplo-HSCT scoring system could effectively predict TRM after transplantation.

CMV Infection and CMV-Specific Immune Reconstitution Following Haploidentical Stem Cell Transplantation: An Update

Haploidentical stem cell transplantation (haploSCT) has advanced to a common procedure for treating patients with hematological malignancies and immunodeficiency diseases. However, cure is seriously hampered by cytomegalovirus (CMV) infections and delayed immune reconstitution for the majority of haploidentical transplant recipients compared to HLA-matched stem cell transplantation. Three major approaches, including in vivo T-cell depletion (TCD) using antithymocyte globulin for haploSCT (in vivo TCD-haploSCT), ex vivo TCD using CD34 + positive selection for haploSCT (ex vivo TCD-haploSCT), and T-cell replete haploSCT using posttransplant cyclophosphamide (PTCy-haploSCT), are currently used worldwide. We provide an update on CMV infection and CMV-specific immune recovery in this fast-evolving field. The progress made in cellular immunotherapy of CMV infection after haploSCT is also addressed. Groundwork has been prepared for the creation of personalized avenues to enhance immune reconstitution and decrease the incidence of CMV infection after haploSCT.

Upfront Alternative Donor Transplant versus Immunosuppressive Therapy in Patients with Severe Aplastic Anemia Who Lack a Fully HLA-Matched Related Donor: Systematic Review and Meta-Analysis of Retrospective Studies, on Behalf of the Severe Aplastic Anemia Working Party of the European Group for Blood and Marrow Transplantation

Idiopathic aplastic anemia is a rare and life-threatening disorder, and hematopoietic stem cell transplantation (HSCT) from a matched sibling donor (MSD) is the standard treatment strategy for young patients. Alternative donor transplantation (ADT) from a matched unrelated donor or an HLA haploidentical donor is not commonly used in the frontline setting. This systematic review/meta-analysis was conducted to compare ADT as an upfront, rather than delayed, treatment strategy in the absence of an MSD to immunosuppressive therapy (IST) in severe aplastic anemia (SAA). We searched PubMed/MEDLINE and Embase (1998 to 2019) for studies that compared the outcomes of ADT with IST as upfront therapy in patients with SAA. We included studies with 5 patients or more in each arm. Studies that included patients with inherited forms of bone marrow failure syndromes were excluded. The primary outcome was the 5-year overall survival (OS) rate. Five studies met the inclusion criteria and were included in this meta-analysis. The pooled 5-year odds ratio (OR) for OS was statistically significant at 0.44 (95% confidence interval [CI], 0.23 to 0.85) in favor of upfront ADT. In addition, survival was compared between upfront ADT versus salvage ADT in 6 studies. The pooled 5-year OR for OS was statistically significant at 0.31 (95% CI, 0.15 to 0.64) in favor of upfront ADT. Although this analysis has some limitations, including the retrospective nature of the included studies, the lack of ethnic diversity, the predominantly pediatric population, and the relatively suboptimal IST regimen used in some of the studies, it indicates that upfront ADT is a potential alternative treatment option in young and pediatric SAA patients who lack an HLA identical sibling donor, particularly when optimal IST is not available. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Successful haploidentical transplantation using plasma exchange and post-transplantation cyclophosphamide for severe aplastic anemia patients with anti-human leukocyte antigen donor-specific antibodies

Haploidentical allogeneic hematopoietic stem cell transplantation (Haplo-HSCT) has emerged as a novel strategy to treat patients suffering from severe aplastic anemia (SAA) who lack matched donors due to the availability and easy access to sources of donors. Anti-human leukocyte antigen donor-specific antibodies (DSAs) have been found to influence the outcome of Haplo-HSCT. Between March 2016 and March 2020, 7 SAA patients with DSAs underwent Haplo-HSCT in our center. We employed a modified protocol of post-transplantation cyclophosphamide and plasma exchange aiming to decrease the levels of DSAs. All 7 patients successfully achieved hematopoietic reconstruction. The median follow-up is 31 (range, 8 to 45) months. They survived and were transfusion-independent in the absence of clonality. No occurrence of primary or secondary graft failure has been noted among any of the patients. There was no severe acute and chronic GVHD occurred. This protocol is effective for Haplo-HSCT in SAA patients with DSAs, which provides an option for the SAA patients without other alternative donor.

Optimizing outcomes for haploidentical hematopoietic stem cell transplantation in severe aplastic anemia with intensive GVHD prophylaxis: a review of current findings

Introduction: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has resulted in increased levels of disease-free survival in severe aplastic anemia (SAA). Haploidentical transplantation (haplo-SCT) was previously not recommended due to unacceptable incidences of graft-versus-host disease (GvHD) and graft failures. With the advent of intensive GvHD prophylaxis strategies, the outcomes obtained with haplo-SCT for SAA have gradually improved.Areas covered: A comprehensive search considered PubMed reported articles before 1 February 2021, presented abstracts, and clinical trials pertaining to haplo-HSCT for SAA. This manuscript covers modern approaches with intensive GvHD prophylaxis in haplo-SCT for SAA. The representative methods consist of granulocyte colony stimulating factor (G-CSF) plus ATG-based and posttransplantation cyclophosphamide (PT-Cy)-based protocols.Expert opinion: Currently, haplo-SCT has become a feasible option for treating SAA. The G-CSF/ATG-based protocol included the largest sample size and reported comparable survival rates with identical siblings. The PT-Cy protocol resulted in a relatively lower incidence of GvHD and seemingly poorer but continuously improved engraftment with augmented conditioning. The optimized outcomes are constantly updated with the modification of the conditioning regimen, donor selection, graft source and GvHD prophylaxis. In the future, we should pay more attention to quality of life in addition to survival, and personalized haplo-SCT may improve outcomes.

Haploidentical Transplantation with Modified Post-transplantation Cyclophosphamide for Patients with Primary Aplastic Anemia: A Multicenter Experience

Aplastic anemia (AA) is a life-threatening hematological disorder that can be cured by hematopoietic stem cell transplantation. Haploidentical transplantation becomes an alternative choice for patients in the absence of a matched sibling donor. We used a retrospective study aimed to confirm the feasibility of busulfan-based modified post-transplantation cyclophosphamide (PTCY) strategy in haploidentical hematopoietic stem cell transplantation for AA patients. We analyzed the outcomes of 27 patients from 3 clinical centers who had undergone haploidentical transplantation between October 2018 and July 2020. The modified condition regimen consisted of anti-thymoglobulin/antilymphocyte globulin, fludarabine, busulfan and low-dose cyclophosphamide, and high-dose cyclophosphamide, mycophenolate mofetil (MMF) and tacrolimus were administered as graft versus host disease (GVHD) prophylaxis after transplantation. The median follow-up time was 370 (range 65-721) days. One patient developed primary graft failure, and successful engraftment was observed in 96.29% (95% confidence interval [CI], 93.45%-97.91%) of patients. The median times for neutrophil and platelet engraftment were 13 (range 11-18) days and 13 (range 11-28) days, respectively. The most common regimen-related toxicity was bladder toxicity, followed by stomatitis and gastrointestinal toxicity. The cumulative incidence of grade II-IV aGVHD was 25.93% (95% CI, 5.84%-52.64%), whereas the cumulative incidence of grade III-IV aGVHD was 7.4% (95% CI, 0%-52.16%). Chronic GVHD was observed in 3 patients by the end of follow-up. All 27 patients are alive, with a failure-free survival rate of 96.30% (95% CI, 6.49%-99.47%) and GVHD relapse-free survival rate of 88.89% (95% CI, 69.39%-96.28%). Virus reactivation was comparable, with rates of 53.54% for cytomegalovirus (CMV) reactivation and 41.57% for Epstein-Barr virus, but the CMV diseases and post-transplantation lymphoproliferative disorder were rare. Our study using haploidentical transplantation with modified PTCY demonstrated an encouraging result with prolonged survival and reduced complications for aplastic anemia patients.

Haploidentical stem cell transplantation for aplastic anemia: the current advances and future challenges

Haematopoietic stem cell transplantation (HSCT) is a curative option for severe aplastic anemia (SAA). Finding a suitable matched donor in a timely manner is a challenge. The availability of haploidentical donors and their successful use in transplantation have expanded valid choices for SAA. In recent decades, haploidentical HSCT (haplo-HSCT) for the treatment of SAA has been continuously attempted, and great strides have been made. Nowadays, haplo-HSCT using different regimens has overcome the difficulty of graft failure and severe graft-versus-host disease (GvHD), and achieved inspiring survival outcomes in SAA. The regimens consist mainly of granulocyte colony-stimulating factor (G-CSF) plus antithymocyte globulin (ATG), posttransplantation cyclophosphamide (PT-Cy), and ex vivo graft T-cell depletion (TCD). In particular, the G-CSF and ATG-based regimen includes the largest sample size and the successful wide use of the G-CSF and ATG-based regimen has promoted haplo-HSCT a higher priority in SAA patients without matched related or unrelated donors in China. Recent studies have also indicated that haplo-HSCT using PT-Cy or TCD regimen is a practicable alternative, but the sample size is relatively small. Here, we offer an overview of clinical results obtained through the use of haploidentical transplantation in SAA, mainly focusing on current advances and future challenges.

Current insights into the treatments of severe aplastic anemia in China

Recently, several studies have been conducted to generate considerable evidence regarding unique treatments for severe aplastic anemia (SAA) in China. Haploidentical donor hematopoietic stem cell transplantation (HID-HSCT) showed an overall survival rate (80.3-86.1%) comparable to those with immunosuppressive therapy (IST) and matched related donor (MRD)- and matched unrelated donor (MUD)-HSCT. Failure-free survival of HID-HSCT was also comparable (76.4-85.0%) to those of MRD- and MUD-HSCT and better than IST in patients < 40 years. Although these results are promising, HID-HSCT should be regarded as a salvage therapy when young patients fail to respond to IST. Porcine anti-human lymphocyte immunoglobulin (pALG) showed similar or superior overall response at 6 months compared to rabbit anti-human thymocyte immunoglobulin (rATG) (64.0-79.4% in the pALG-group vs.48.1-64.7% in the rATG-group) as a first-line IST. Promising hematological response (28.4-33.3%) was observed in patients with refractory AA following infusion of the mesenchymal stromal cells (MSCs) derived from the bone marrow of allogeneic donors. pALG can replace rATG as an immunosuppressive drug and MSCs infusion can be used as a second-line treatment for refractory SAA. We believe that this review contributes to refine the global practices for SAA treatment.

Haploidentical hematopoietic stem cell transplantation in aplastic anemia: a systematic review and meta-analysis of clinical outcome on behalf of the severe aplastic anemia working party of the European group for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia (AA) is a serious hematological disorder, which is solely cured by hematopoietic stem cell transplantation (HSCT). Haploidentical HSCT is an emerging modality with encouraging outcomes in several blood conditions. The present study aims to comprehensively assess the feasibility and safety of haploidentical HSCT in patients with severe and very severe AA. It is a systematic review and meta-analysis of studies related to haploidentical stem cell transplantation in idiopathic AA investigating rates of successful engraftment, acute graft-versus-host disease (aGvHD), chronic GvHD (cGvHD), transplant-related mortality (TRM), and posttransplantation viral infections (including cytomegalovirus [CMV]) in patients with AA. The effects of reduced-intensity conditioning (RIC) and nonmyeloablative conditioning (NMA), as well as various GvHD prophylaxis regimens on these outcomes were evaluated. In total 15 studies were identified, (577 patients, 58.9% males), successful engraftment was observed in 97.3% of patients (95% CI, 95.9-98.7) while grades II-IV aGvHD and cGvHD were reported in 26.6% and 25.0%, respectively. The pooled incidence of TRM was 6.7% per year (95% CI, 4.0-9.4). RIC regimens were associated with higher proportions of successful engraftment (97.7% vs 91.7%, P = 0.03) and aGvHD (29.5% vs 18.7%, P = 0.008) when compared with NMA regimens with no differences in cGvHD or mortality incidence. When compared with methotrexate-containing regimens and other regimens, posttransplant cyclophosphamide-containing regimens reduced the rates of aGvHD (28.6%, 27.8%, and 12.8%, respectively, P = 0.02), CMV viremia (55.7%, 38.6%, and 10.4%, respectively, P < 0.001), and CMV disease in initially viremic patients (2.1%, 33.0%, and 0%, respectively, P < 0.001). We have concluded that Haploidentical HSCT was associated with promising outcomes in terms of successful engraftment and reduced complications. Future prospective trials are needed to identify the preferred conditioning regimen, GvHD prophylaxis, and graft source in the setting of haploidentical transplant for AA.

Comparison of hemorrhagic and ischemic stroke after allogeneic hematopoietic stem cell transplantation

Stroke is an important complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Nevertheless, few studies have been published to analyzed the occurrence and prognosis of stroke after allo-HSCT. From January 2007 to December 2018 in Peking University People's Hospital, 6449 patients received HSCT and there were 2.3% of patients diagnosed with stroke after allo-HSCT (hemorrhagic: 1.0%, ischemic: 1.3%). The median time to hemorrhagic and ischemic stroke after HSCT was 161 days and 137 days, respectively. In total, 8.4% of patients experienced neurological sequelae. The outcome was much worse in patients with stroke than in control subjects. The comparison of prognosis showed no statistical differences between patients with hemorrhagic stroke and those with ischemic stroke. Significant risk factors for hemorrhagic stroke were pretransplant central nervous system leukemia (CNSL), and delayed platelet engraftment. Risk factors associated with the occurrence of ischemic stroke included high-risk disease, prior venous thromboembolism (VTE), grade III-IV acute graft-versus-host disease (aGVHD), and thrombotic microangiopathy (TMA). Haplo-identical transplantation was not a risk factor for stroke and had no impact on the prognosis compared with HLA-matched HSCT. Altogether, these results show that stroke is a severe complication after allo-HSCT. The prognosis of posttransplant stroke did not differ between hemorrhagic and ischemic stroke.

Comparable survival outcome between transplantation from haploidentical donor and matched related donor or unrelated donor for severe aplastic anemia patients aged 40 years and older: A retrospective multicenter cohort study

This retrospective multicenter cohort study aimed to compare the outcome of haploidentical hematopoietic stem cell transplantation (HID-HSCT) with matched sibling donor (MSD) and unrelated donor (URD) transplantation in severe aplastic anemia (SAA) patients 40 years of age and older. With a median follow-up time of 17.6 months, 85 consecutive patients were enrolled in the study, and the median patient age was 45 years (40, 58). The cumulative engraftment rates of neutrophil and platelet were 98.8 ± 0.0% and 92.9 ± 0.1%. The cumulative incidences of Grade 2-4 acute graft-versus-host disease (aGvHD) and chronic graft-versus-host disease (cGvHD) at 3 years were 14.1 ± 0.1% and 17.3 ± 0.2%. The 3-year estimated overall survival (OS) and failure-free survival (FFS) were 91.2 ± 3.2% and 89.7 ± 3.5%. In multivariate analysis, the only factor associated with inferior survival was an ECOG score ≥2. HID-HSCT was associated with a higher incidence of GvHD, but the difference of 3-year estimated OS between HID group and the other two cohorts was not significant (86.7 ± 6.4% for HID vs 92.1% ± 4.4% for MSD and 100% for URD, P = .481). HID-HSCT might be a feasible alternative option for selected SAA patients aged 40 years and older without a matched donor.

Revisiting acquired aplastic anaemia: current concepts in diagnosis and management

Acquired aplastic anaemia is a rare, serious, immunologically mediated bone marrow failure syndrome, characterised by marrow hypoplasia of varying severity and significant pancytopenia. Careful attention and investigation, including molecular testing, is required to confirm the diagnosis and exclude other mimicking conditions, such as inherited bone marrow failure syndromes. In a proportion of patients, the disease evolves to myelodysplasia or acute myeloid leukaemia and in some there is an association with paroxysmal nocturnal haemoglobinuria. The disease has a major impact on patient quality of life. Haemopoietic stem/progenitor cell transplantation for eligible patients with an available donor is the only current curative therapy. Other patients may receive immunosuppression, most commonly with anti-thymocyte globulin and cyclosporin. An initial response to immunosuppression is often encouraging, but relapse is common. Supportive care, including management of transfusion requirements and infections, is central to management. Promising new diagnostic tools and emerging therapies will likely transform approaches to this important, chronic and life-threatening condition.

Posttransplant cyclophosphamide in allogeneic bone marrow transplantation for the treatment of nonmalignant hematological diseases

We present a single-center retrospective series of allogeneic bone marrow transplantation (BMT) with the use of posttransplant cyclophosphamide (PTCy) in the setting of nonmalignant hematological conditions. Nine patients were treated between 2013 and 2019. Nonmyeloablative conditioning consisted of antithymocyte globulin, fludarabine, low-dose cyclophosphamide, and total body irradiation (200cGy) followed by allogeneic bone marrow infusion. Post-BMT GVHD prophylaxis was with PTCy, tacrolimus, and mycophenolate mofetil. At a median follow-up of 24 months (range 4, 63), all patients are alive, with donor-derived hematopoiesis and free of significant acute or chronic GVHD. Donors were haploidentical (n = 6), fully matched unrelated (n = 2), and fully matched sibling (n = 1). Neutrophil and platelet engraftment occurred at a median of 21 days and 33 days, respectively, after transplantation. Three patients (3/9, 33%) experienced stage 1-2 acute skin GVHD. The only cases of chronic GVHD are in three patients (3/9, 33%) with ocular disease (two mild, one moderate). No patient has required systemic immunosuppression beyond 12 months after BMT. PTCy-based nonmyeloablative allogeneic BMT is safe and effective for nonmalignant hematologic conditions and should be prospectively compared with historical regimens.

Who is the best haploidentical donor for acquired severe aplastic anemia? Experience from a multicenter study

BACKGROUND

Haploidentical transplantation has been proposed as an effective treatment for severe aplastic anemia (SAA). The majority of patients have more than one HLA-haploidentical donor. Herein, we compared the outcomes between different donor-recipient relationships for optimal haploidentical donor selection in acquired SAA.

METHODS

We conducted a multicenter study based on a registered database of 392 patients with SAA treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT) between 2006 and 2018. In total, 223 patients received grafts from father donors, 47 from mother donors, 91 from siblings, 29 from children, and 2 from collateral donors.

RESULTS

Of the 381 patients who survived more than 28 days, 379 (99.5%) recipients were engrafted. The 2-year overall survival (OS) was 86.6 ± 2.5%, 87.1 ± 4.9%, 84.3 ± 3.9%, and 92.2 ± 5.1% for recipients of father, mother, sibling, and child grafts, respectively, (P = 0.706). The 2-year failure-free survival (FFS) was 82.8 ± 2.7%, 86.7 ± 5.1%, 80.8 ± 4.2%, and 92.5 ± 5.1% for recipients of father, mother, sibling, and child grafts, respectively, (P = 0.508). There was no difference in the incidence of either acute or chronic graft-versus-host disease (GVHD) among the different donor sources in multivariate analyses. There were also no differences in the OS or FFS among the different donor sources in the Cox regression analysis. However, OS was significantly better in the patients with a shorter history of aplastic anemia (< 12 months), better performance status (ECOG scores 0-1), or moderate graft mononuclear cell (MNC) counts (6-10 × 10⁸/kg), and in female recipients with male donors. The FFS was also higher in patients with a shorter history of aplastic anemia (< 12 months) and better performance status (ECOG scores 0-1).

CONCLUSIONS

Fathers, mothers, siblings, and children are all suitable haploidentical donors for patients with SAA.

[Haploidentical allogenetic hematopoietic stem cell transplantation for X-linked adrenoleukodystrophy]

OBJECTIVE

X-linked adrenoleukodystrophy (ALD) is a severe inherited disorder leading to rapid neurological deterioration and premature death. Allogeneic hematopoietic stem cell transplantation (HSCT) is still the only treatment that halts the neurologic symptoms in ALD. However, many patients lack suitable human leukocyte antigen (HLA) matched related donors and must rely on alternative donors for a source of stem cells. The purpose of this study was to explore the outcomes of haploidentical allogeneic stem cell transplantation for ALD patients.

METHODS

Between December 2014 and December 2018, eight children with ALD lacking HLA matched related or unrelated donors were treated with haploidentical allogeneic hematopoietic stem cell transplantation. The patients received conditioning regimen with busulfan 9.6 mg/kg, cyclophosphamide 200 mg/kg and fludarabine 90 mg/m². Graft-versus-host disease (GVHD) prophylaxis consisted of anti-human thymocyte globulin, cyclosporine A, mycophenolate mofetil and short course of methotrexate.

RESULTS

All the 8 children received allogeneic stem cell transplants from their fathers. The median age of the recipients was 8 (range: 5-12) years. The median age of the donors was 36 (range: 32-40) years. All the recipients received granulocyte colony-stimulating factor (G-CSF) mobilized bone marrow and peripheral blood-derived stem cells. The median number of total mononuclear cells dose and CD34+ dose was 10.89 (range: 9.40-12.16)×10⁸/kg and 7.06 (range: 0.74-7.80)×10⁶/kg, respectively. Neutrophil engraftment occurred a median of 11 days (range:8-13 days) after transplantation. Platelet engraftment occurred a median of 10 days (range:8-12 days) after transplantation. All the patients achieved complete donor chimerism at the time of engraftment. Four patients had grades II-IV acute GVHD and 1 had chronic graft-versus-host disease. No severe chronic GVHD occurred. Among all the children, 2 had cytomegalovirus (CMV) DNAemia and 2 Epstein-Barr virus (EBV) DNAemia. Overall, seven of them survived and had no major complications related to transplantation. One died of cerebral hernia after epilepsy 125 days after transplantation.

CONCLUSION

The preliminary observation demonstrates that haploidentical allogeneic stem cell transplantation with this novel regimen could successfully achieve full donor chimerism in ALD patients. According to our experience, haploidentical allogeneic hematopoietic stem cell transplantation is safe and feasible in the treatment of X-linked adrenoleukodystrophy.

Haploidentical donor transplants for severe aplastic anemia

Haploidentical stem cell transplantation (HAPLO) is being increasingly used, and significant progress has been made both with ex vivo T-cell depleted grafts as well as with unmanipulated marrow or peripheral blood grafts. We here review the current status of HAPLO grafts in patients with acquired severe aplastic anemia. Several transplant platforms have been tested, to overcome graft severe rejection and graft vs host disease (GvHD): these include differences in the conditioning regimen, in graft source and graft manipulation, and in GvHD prophylaxis. The latter include ex vivo T-cell depletion and/or antithymocyte globulin and/or high dose post-transplant cyclophosphamide. Some programs also include the use of marrow or cord blood mesenchymal stem cells, infused at the time of transplantation. Extremely encouraging results are being reported especially in the pediatric population, but also in young adults: we will review reports on 375 patients, with an average rejection rate of 6%, grade II-IV GvHD of 23% and 1-year survival of 80%. Finally we will discuss the place of HAPLO transplants in the context of alternative donor grafts for acquired aplastic anemia.

Immunosuppressive therapy versus haploidentical transplantation in adults with acquired severe aplastic anemia

Our study aimed to compare treatment outcomes between hematopoietic stem cell transplantation (HSCT) from haploidentical donors (HID) and immunosuppressive therapy (IST) in adults with acquired severe aplastic anemia (SAA). The medical records of 113 SAA adults who received IST, including rabbit ATG and cyclosporin (N = 37), or HID HSCT (N = 76) within 6 months of diagnosis at two institutions were retrospectively reviewed. Estimated 8-year overall survival (OS) was comparable between the IST and HID HSCT groups (75.6 vs. 83.7%, respectively, P = 0.328), but failure free survival (FFS) was significantly lower in IST group than HID HSCT group (38.5 vs. 83.7%, respectively, P = 0.001). Furthermore, a significant improvement in FFS was observed with HSCT over IST in patients under 40 years old. At the last follow-up, patients in HSCT group achieved better Karnofsky Performance Status (KPS) than those in IST group (100 [20-100] vs. 90 [20-100], P = 0.002). In terms of blood count, 83.1% (54/65) of patients in HSCT group showed complete recovery compared to only 38.2% (13/34) in IST group (P < 0.001). These data suggest that HID HSCT could be an effective alternative treatment option for SAA adults, and additional prospective studies are necessary.