Alternative donor transplants for severe aplastic anemia

Recombinant Human Thrombopoietin Promotes Platelet Engraftment in Severe Aplastic Anemia Patients Following Treatment With Haploid Hematopoietic Stem Cell Transplantation using Modified Post-Transplantation Cyclophosphamide

BACKGROUND

Recombinant human TPO (rhTPO) promotes platelet engraftment in patients after allogeneic HSCT (allo-HSCT). However, the effects of rhTPO on platelet recovery after Haplo-HSCT in patients with severe aplastic anemia (SAA) have not been intensively studied.

OBJECTIVE

We aimed to evaluate the efficacy of rhTPO on platelet engraftment in patients with SAA who were treated with Haplo-HSCT using post-transplantation cyclophosphamide (PTCy).

STUDY DESIGN

SAA patients who received Haplo-HSCT plus PTCy regimen were divided into the rhTPO group (with subcutaneous injection of rhTPO, n = 28) and Control group (no rhTPO administration, n = 27). The engraftment of platelet/neutrophil, platelet infusion amount, and transplant-related complications between the 2 groups were compared.

RESULTS

All 55 patients showed successful hematopoietic reconstitution. The median time of platelet engraftment was 11 (9 to 29) days in the rhTPO group and 14 (9 to 28) days in the Control group (P = .003). The rhTPO group had a significantly reduced amount of infused platelets compared to the Control group (2 (1 to 11.5) versus 3 (1 to 14) therapeutic doses; P = .004). There was no significant difference between the 2 groups regarding median time of neutrophil engraftment, incidence of acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD), incidence of cytomegalovirus or Epstein-Barr virus reactivation, 3-yr overall survival rate, and failure-free-survival rate. No obvious adverse reactions were observed in the rhTPO group.

CONCLUSION

rhTPO promoted platelet engraftment, reduced the amount of transfused platelets, and demonstrated good safety profiles without evidence of adverse reactions in patients with SAA who received Haplo-HSCT using PTCy regimen.

Comparison of Stem Cell Transplantation Using Unrelated, Haploidentical, and Sibling Donors for Patients with Acquired Severe Aplastic Anemia: A Single-Center Retrospective Cohort Study

The preferred donor (haploidentical donor [HID] versus matched unrelated donor [URD]) choice in patients with acquired severe aplastic anemia (SAA) who lack an HLA-matched sibling donor (MSD) and fail upfront immunosuppressive treatment (IST) therapy is unknown. We retrospectively investigated SAA patients (n = 58) who underwent allogeneic stem cell transplantation (allo-SCT) between January 2012 and October 2022. The 5-year overall survival (OS) and 5-year failure-free survival (FFS) were comparable among the URD (n = 8), HID (n = 25), and MSD (n = 25) cohorts (OS: mean, 87.5 ± 11.7% versus 98.0 ± 6.5% versus 83.3 ± 7.6% [P = .926]; FFS: mean, 60.0 ± 18.2% versus 87.0 ± 7.0% versus 78.3 ± 8.6% [P = .222]). Multivariate analysis revealed that primary engraftment failure independently predicted OS and secondary graft failure predicted FFS among SAA patients who underwent allo-SCT, but donor type and age were not predictive of these outcomes. An urgent second SCT for patients with engraftment failure may be an effective salvage treatment. Our findings show that an alternative donor SCT is indicated for eligible SAA patients without an MSD even if age ≥40 years.

Shifting Paradigms: The Case of Autologous Reconstitution after an Upfront Matched Unrelated Hematopoietic Cell Transplantation for Severe Acquired Aplastic Anemia in a Child

During the last few years, the therapeutic landscape of idiopathic aplastic anemia (IAA) has been profoundly revolutionized by the increased use of alternative transplant procedures, such that today hematopoietic cell transplantation (HCT) from a matched unrelated donor (MUD) has been suggested as a possible first line strategy in pediatric patients with severe IAA, in the absence of a matched related donor. However, in this particular context, outcomes and early and long-term toxicities remain to be determined, as compared to non-transplant procedures. While prospective trials are ongoing, we report here the case of a 12-year-old boy with IAA, receiving an upfront bone marrow HCT from a MUD, who experienced early graft rejection associated with autologous hematological recovery, which could induce remission of his hemopathy. This case offers the opportunity to discuss the challenges associated with these new transplant paradigms and provides a brief review of the literature regarding the issue of autologous recoveries after allogeneic HCT in IAA.

The efficiency of human umbilical cord mesenchymal stem cells as a salvage treatment for steroid-refractory acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is a life-threatening complication after hematopoietic stem cell transplantation (HSCT) and is primarily treated with steroids. However, there is no standard treatment for steroid-refractory acute graft-versus-host disease (SR-aGVHD). Although mesenchymal stem cells (MSCs) have proven effective for SR-aGVHD, few reports have focused on human umbilical cord blood-derived MSCs (hUCB-MSCs). Here, we report on the efficiency of hUCB-MSCs as the salvage therapy for SR-aGVHD in 54 patients. The overall response rate (ORR) reached 59.3% (32/54) 28 days later. Twenty-four patients achieved complete remission (CR), and 8 achieved partial remission (PR). The median follow-up time after the initiation of hUCB-MSC treatment was 19.3 (0.6-59.0) months. The probability of overall survival (OS) and progression-free survival (PFS) was 60.9% (47.4-74.4%, 95% CI) and 58.8% (45.3-72.3%, 95% CI), respectively, while that of GVHD/relapse-free survival (GRFS) was only 30.8% (17.86-43.74%, 95% CI). Multivariate analysis revealed that response on Day 28 was an independent favorable prognostic factor (OS, P < 0.001; PFS, P < 0.001; GRFS, P = 0.001), but an age of ≥ 18 years suggested an unfavorable long-term prognosis (OS, P < 0.001; PFS, P < 0.001; GRFS, P = 0.003). In addition, liver involvement was adversely associated with PFS (P = 0.021) and GRFS (P = 0.009). An infused MNC ≥ 8.66 × 108/kg was also detrimental to GRFS (P = 0.031). Collectively, our results support hUCB-MSCs as an effective treatment for SR-aGVHD.

How to optimize outcome of patients undergoing HLA-matched related haematopoietic stem cell transplantation in acquired and inherited bone marrow failure syndromes

Up-front allogeneic haematopoietic stem cell transplantation (allo-HSCT) after a reduced intensity conditioning regimen is the standard treatment in children with acquired severe aplastic anaemia (aSAA) and inherited bone marrow failure syndromes (iBMFs) in the presence of a healthy matched related donor (MRD). The paper by Alsultan et al. report the safety and efficacy of MRD HSCT conditioned with low-dose cyclophosphamide, fludarabine and thymoglobulin in both aSAA and non-Fanconi iBMFs, strengthening the concept of the pivotal role of immunosuppressive approach in allo-HSCT for specific subgroups of non-malignant diseases requiring a reduced risk of toxicities, offering the opportunity to discuss the essential points for achieving patients' long-term survival after MRD HSCT in BMF. Commentary on: Alsultan et al. Human leucocyte antigen-matched related haematopoietic stem cell transplantation using low-dose cyclophosphamide, fludarabine and thymoglobulin in children with severe aplastic anaemia. Br J Haematol 2023;203:255-263.

Case Series Using Salvage Haplo-Identical Stem Cells for Secondary Transplantation

In order to expand the donor pool and accessibility of the transplant procedure, it was necessary to introduce haplo-identical stem cell transplants in the Fundeni Clinical Institute from 2015. Even if the Romanian population is an ethnically compact white population, many of the patients referred for bone marrow transplant lack a suitable donor. Hematopoietic stem cell transplant from a haplo-identical donor is an alternative option for those patients without an HLA (Human Leucocyte Antigen)-matched donor (sibling or matched unrelated). This procedure was used also as a salvage option for those who experienced engraftment failure or the rejection of the first stem cell graft. In this case series, we present three such cases, with a haplo-transplant used as a salvage protocol (after an engraftment failure or rejection of the first transplanted cells). The patients we present were diagnosed with AML (acute myeloid leukemia) with MDS (myelodysplastic syndrome), MDS-RAEB 2 (myelodysplastic syndrome-refractory anemia with excess blasts 2), and SAA (severe aplastic anemia). In two of the three cases, the engraftment failure may have been due to the conditioning Fludarabine/Busulfan/Cyclophosphamide (Flu/Bu/CFA) used, combined with marrow grafts. In all three cases, the second transplant was of haplo-identical peripheral blood stem cells using Melphalan/Fludarabine (Mel/Flu) conditioning, the cells engrafted properly and the patients experienced complete chimerism, and two of them are alive with an excellent quality of life.

Impact of Iron overload and Iron Chelation with deferasirox on outcomes of patients with severe aplastic anemia after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Patients suffering from severe aplastic anemia (SAA) need frequent blood transfusions during allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, these transfusions can result in an excess of iron in the body tissues, which can negatively impact the success of the transplant.

OBJECTIVES

This study aimed to examine the impact of pre-transplant iron overload (IO) on the outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with severe aplastic anemia (SAA). It also investigated whether iron chelation (IC) therapy was necessary to enhance transplantation outcomes in SAA patients by providing guidelines for determining when excess iron should be chelated.

STUDY DESIGN

The study consisted of two parts: Cohort 1, which was retrospective and conducted from April 2012 to December 2018, divided SAA patients receiving their first allo-HSCT into two groups based on their pre-transplant serum ferritin (SF) levels: the iron overload (IO) group (SF >1000 ng/ml, n=17) and the non-IO group (SF ≤ 1000 ng/ml, n=48). Cohort 2 was a prospective clinical trial conducted from January 2019 to July 2020. It involved SAA patients diagnosed with IO who were treated with iron chelation (IC) therapy using deferasirox (DFX) at a dose of 10-30 mg/kg. Patients were separated into two groups based on their pre-transplant SF levels: the IC success (IC^success) group (SF ≤ 1000 ng/ml, n=18) and the IC failure (IC^failure) group (SF >1000 ng/ml, n=28) groups. All participants were evaluated for the correlation between pre-transplant SF levels and transplantation outcomes. A P-value of less than 0.05 was considered statistically significant.

RESULTS

There was no significant difference in the speed of engraftment for the three lineages or in the incidence of 100-day grade II-IV acute graft-versus-host disease (aGVHD), grade III-IV aGVHD, or 3-year chronic GVHD between the two groups in both cohorts. However, in cohort 1, it was noteworthy that 1-year OS (83.3% vs. 41.2%, p < 0.001) and 3-year OS (83.3% vs. 35.3%, p < 0.001) were significantly worse in the IO group. Furthermore, 180-day TRM (14.6% vs. 47.1%, p = 0.005) and 1-year TRM (16.7% vs. 52.9%, p = 0.002) were significantly higher in the IO group. The IO group was significantly associated with inferior 3-year OS in both univariate and multivariate analyses. In cohort 2, it was found that 1-year OS (42.9% vs. 88.9%, p = 0.003) and 3-year OS (42.9% vs. 83.3%, p = 0.007) were significantly better in the IC^success group, while 180-day TRM (11.1% vs. 39.3%, p = 0.040) and 1-year TRM (11.1% vs. 57.1%, p = 0.003) were significantly lower in the IC^success group. These differences were confirmed in both univariate and multivariate analyses.

CONCLUSIONS

The study involving two cohorts showed that pre-HSCT iron overload has a negative impact on transplantation outcomes in SAA patients. Chelating excess iron with a serum ferritin level below 1000 ng/ml was found to be necessary and could potentially improve the outcomes.

Alternative Transplantation With Post-Transplantation Cyclophosphamide in Aplastic Anemia: A Retrospective Report From the BMF-WG of Hunan Province, China

Although the possibility of first-line hematopoietic cell transplantation (HCT) from alternative donors in severe aplastic anemia (SAA) patients has been suggested recently, transplantation strategies are still being investigated. We established a novel post-transplantation cyclophosphamide-based HCT protocol for patients with SAA in prior studies. We explores the effectiveness and safety of this HCT approach either as first-line or as salvage treatment in SAA patients. Outcomes of 71 consecutive young patients, who received HCT from unrelated or haploidentical donors, were retrospectively analyzed. According to their treatment before transplantation, the patients were classified into treatment-naive (TN) and relapsed or refractory (R/R) patients. The R/R patients were designated as such when a patient did not respond to previous immunosuppressive therapy or relapsed. We administered an antithymocyte globulin (ATG)-free, total body irradiation (TBI)-free conditioning regimen comprising cyclophosphamide, busulfan, and fludarabine, all in an intravenous formula. We used a thorough post-transplantation prophylaxis regimen for GVHD, including post-transplantation cyclophosphamide (PTCy) and short-term methotrexate and long-term cyclosporine A. The median age of the cohort was 16 (95% confidence interval, 12-20) years at transplantation. Most patients (61 of 71) received HCT from haploidentical donors, and the others received HCT from unrelated donors. TN patients (n = 38) were younger and had a shorter time-to-transplant and lower HCT-specific comorbidity index than patients with R/R diseases (n = 33). The frequencies of graft failure, grade II-IV acute graft-versus-host disease (GVHD), and moderate-severe chronic GVHD were similar, at 5.3% versus 6.5% (P = .057), 8.3% versus 0% (P = .109), and 5.7% versus 0% (P = .199) between R/R and TN patients. With a median 42-month follow-up, the frequencies of overall survival (OS) and event-free survival (EFS) were higher in the TN group than in the R/R group (100% versus 84.8% [P = .013] and 86.8% versus 75.8% [P = .255], respectively). All patients who achieved successful engraftment showed full donor chimerism. Four patients, all in the R/R group, suffered from donor-type aplasia; of these, 2 died, 1 was salvaged with another transplantation, and the final one was still receiving transfusion at the last follow-up. Currently, 93.9% (62 of 66) of the patients are alive more than 12 months after transplantation; of these 93.5% (58 of 62) no longer receive immunosuppression, including 91.7% (33 of 34) of the TN group and 89.3% (25 of 28) in the R/R group. This novel TBI-free and ATG-free HCT protocol using a reduced-intensity conditioning regimen followed by modified PTCy achieved promising engraftment, minimal GVHD risk, and encouraging OS and EFS. Our study suggests that unrelated or haploidentical HCT with PTCy can be used as a first-line treatment for young patients with SAA. Nevertheless, further efforts are needed to explore possibilities for older patients and patients with a poor performance status.

Comparisons of unmanipulated haploidentical donor, unrelated cord blood donor and matched unrelated donor hematopoietic stem cell transplantation in pediatric acquired severe aplastic anemia: a single center study

We retrospectively analyzed the outcomes of 240 pediatric SAA patients who underwent unmanipulated alternative HSCT between September 2012 and November 2020 at our center. The incidence of GF (PGF + SGF) was higher in the UCBD cohort compared to the MUD and HID cohorts [(13.5% ± 6.5%) vs (0%), and (1.6% ± 5.3%), respectively, p = .0001]. The incidence of platelet engraftment within 180 days post-HSCT was lower in the UCBD cohort (82.4% ± 2.3%) compared to the HID group (96.2% ± 1.3%) and the MUD group (97.4% ± 0.5%) (p = .020). the median duration time for platelet engraftment in the UCBD cohort was 29 days, longer than in HID cohort 14 days and the MUD cohort 13 days (p = .005). UCBD cohort had a lower 3-year failure-free survival (FFS) (70.5% ± 8.4%) compared to the HID cohort (81.1% ± 4.3%) and the MUD cohort (92.5% ± 3.1%) (p = .030) and lower 3-year GVHD/relapse free survival (GRFS) (63.3% ± 9.5.4%) compared to the HID cohort (75.5% ± 6.8%) and MUD cohort (87.9% ± 4.5%) (p = .002). UCBD-HSCT had inferior FFS and GRFS compared to an HSCT with an HID or MUD in pediatric patients with acquired SAA. A UCBD-HSCT had a higher GF and lower incidence of platelet engraftment and longer platelet engraftment time.

Dioscin Regulating Bone Marrow Apoptosis in Aplastic Anemia

Background

Aplastic anemia (AA), a disease of bone marrow failure, is caused by CD8⁺T mediated apoptosis of hematopoietic cells. However, traditional immunosuppressive therapy (IST) has severe liver and kidney toxicity and even cannot achieve the expected therapeutic effect in some patients.

Purpose

Our study is aimed to investigate the effect and mechanism of dioscin (DNS) for treating AA.

Methods

Briefly, we established and evaluated the AA mouse model, DNS and positive control drugs were used for intervention treatment. After 14 days of intervention, femoral bone marrow pathology, bone marrow mononuclear cells (BMMCs) apoptosis rate, bone marrow CD34+ cell surface Fas (CD95) expression and Fas signaling pathway key proteins were detected.

Results

After the establishment of the AA mouse model, the number of peripheral blood cells including granulocytes, erythrocytes, hemoglobin, platelets and reticulocytes in the AA group model was significantly decreased compared with the group control (P < 0.01). The degree of bone marrow hyperplasia in the sternum and femur is extremely low. After different drug interventions, compared with the group model, the number of peripheral blood cells in the AA mice rebounded significantly in group DNS (P < 0.01). Not only that the apoptosis rate of BM-MCs decreased (P < 0.01), meanwhile, the CD95 molecule expressed on the CD34+ bone marrow cells had a significant decline (P < 0.01), and the expression level of the key proteins of Fas signaling pathway was also significantly decreased (P < 0.01).

Conclusion

DNS recovered the peripheral pancytopenia and bone marrow failure in AA mice. DNS reduced the key protein of Fas signaling pathway level to inhibit apoptosis of bone marrow cells to treat AA.

A multicentre trial of intensive immunosuppressive therapy combined with umbilical cord blood for the treatment of severe aplastic anaemia

Immunosuppressive therapy (IST) is an effective treatment regimen for severe aplastic anaemia (SAA) patients without HLA-identical donors. This study further compared the outcomes between IST and IIST-UCB in SAA on the basis of research shown that IST combined with umbilical cord blood infusion (IIST-UCB) treated effectively. A total of 123 patients from 11 hospitals in China were enrolled. Sixty-nine patients in IIST-UCB group were treated with ATG + CsA + CTX combined with cord blood, while 54 patients in IST group with ATG + CsA. The overall remission rates (ORRs), complete remission (CR) rates and partial response (PR) rates of IIST-UCB group and IST group at 3 months were 69.67% vs 51.85% (P = .045), 21.74% vs 3.7% (P = .004) and 47.83% vs 48.15% (P = .972), respectively. After 6 months of treatment, they were 76.81% vs 57.41% (P = .022), 37.68% vs 11.11% (P = .001) and 39.13% vs 46.30% (P = .425), respectively. After 1 year of treatment, they were 85.51% vs 61.11% (P = .002), 59.42% vs 25.93% (P = .000) and 26.09% vs 35.19% (P = .275), respectively. The ORRs and CR rates of IIST-UCB group were both significantly higher than IST group after 3 months, 6 months and 1 year of treatment. The neutrophil granulocyte, platelet and haemoglobin recovery times of IIST-UCB group were significantly shorter than IST group. Compared with standard IST, IIST-UCB as an effective therapy for SAA patients without HLA-identical donors accelerated the haematopoietic reconstitution, resulting in higher early CR rates.

Imbalance and dizziness caused by unilateral vestibular schwannomas correlate with vestibulo-ocular reflex precision and bias

Imbalance and dizziness are disabling symptoms for many patients with vestibular schwannomas (VS) but symptom severity typically does not correlate with the vestibulo-ocular reflex (VOR) amplitude-based metrics used to assess peripheral vestibular damage. In this study, we tested the hypothesis that imbalance and dizziness in patients with VS relate to VOR metrics that are not based on response amplitude. Twenty-four patients with unilateral, sporadic VS tumors were studied, and objective (balance) and subjective (dizziness) vestibular dysfunction was quantified. The VOR was tested using two yaw-axis motion stimuli, low-frequency en-bloc sinusoidal, and high-frequency head-on-body impulsive rotations. Imbalance correlated with VOR precision (the inverse of the trial-to-trial variability) and with low-frequency VOR dynamics (quantified with the time constant), and these two metrics were also strongly correlated. Dizziness correlated with the VOR bias caused by an imbalance in static central vestibular tone, but not with dynamic VOR metrics. VOR accuracy (mean response amplitude relative to the ideal response) was not correlated with the severity of imbalance or dizziness or with measures of VOR precision or time constant. Imbalance in patients with VS, therefore, scales with VOR precision and time constant, both of which appear to reflect the central vestibular signal-to-noise ratio, but not with VOR slow-phase accuracy, which is based on the magnitude of the central vestibular signals. Dizziness was related to the presence of a static central tone imbalance but not to any VOR metrics, suggesting that abnormal perception in VS may be affected by factors that are not captured by yaw-axis VOR measurements.NEW & NOTEWORTHY The severity of symptoms associated with unilateral vestibular schwannomas (VS) is poorly correlated with standard yaw-axis vestibulo-ocular reflex (VOR) metrics that are based on response amplitude. In this study, we show that the balance and perceptual dysfunction experienced by patients with VS scales with VOR metrics that capture information about the central signal-to-noise ratio (balance) and central static tone (dizziness), but are not correlated with the VOR gain, which reflects central signal amplitude.

High Failure-Free Survival after Unrelated Donor Peripheral Blood Stem Cell Transplantation in Pediatric Severe Aplastic Anemia

The use of alternative donor peripheral blood stem cell transplantation (PBSCT) has increased in recent years. In this study, we analyzed the effect of stem cell source and HLA disparity on outcomes in pediatric patients with severe aplastic anemia (SAA). A total of 134 patients who underwent HSCT with nonmyeloablative conditioning between 2006 and 2020 were enrolled and classified into 3 groups: HLA-matched bone marrow transplantation (M-BMT; n = 24), HLA-matched PBSCT (M-PBSCT; n = 66), and HLA-mismatched PBSCT (MM-PBSCT; n = 44). Significantly higher stem cell doses were obtained for PBSCT than for BMT. A total of 13 patients experienced secondary graft failure (GF), with a cumulative incidence (CI) of 10.0%. HLA-mismatched PBSCT and a very severe degree of disease significantly decreased the incidence of secondary GF. The CI of grade II-IV acute graft-versus-host disease (GVHD) was significantly higher in PBSCT than in BMT, but the CI of grade III-IV acute GVHD and CI of chronic GVHD requiring systemic treatment did not increase in PBSCT. The estimated 5-year overall survival (OS), failure-free survival (FFS), and GVHD-free failure-free survival (GFFS) of the total cohort were 93.0%, 89.5%, and 77.5%, respectively. The most favorable FFS was observed in the MM-PBSCT group (97.6%; P = .03), whereas OS and GFFS were similar across the 3 groups. In multivariate analysis, HLA mismatch and short time from diagnosis to transplantation were associated with superior FFS. Unrelated donor PBSCT with low-intensity SAA conditioning showed favorable outcomes in terms of low rate of secondary GF, higher FFS, and manageable GVHD regardless of HLA compatibility. Our findings suggest the feasibility of PBSCT from unrelated donors, resulting in the possible expansion of the donor pool in transplantation for pediatric SAA. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

A comparative study of porcine antihuman lymphocyte globulin versus antithymocyte globulin-fresenius in an allogeneic hematopoietic cell transplantation conditioning regimen for severe aplastic anemia

OBJECTIVES

To compare the outcomes of antihuman T lymphocyte globulin (ATG-F) and porcine antihuman lymphocyte globulin (p-ALG) as part of a conditioning regimen in hematopoietic stem cell transplantation (HSCT) for severe aplastic anemia (SAA).

METHODS

we performed a retrospective analysis, evaluating the outcome of patients with SAA who received ATG-F based conditioning (n = 26) with those receiving p-ALG conditioning (n = 34).

RESULTS

The median time to neutrophil engraftment was 11 days (range, 8 - 38) and 11 days (range, 9 - 24) in the p-ALG and ATG-F groups (P = 0.857); the median platelet engraftment time was 15 (range, 9 - 330) days and 13 (range, 10 - 56) days (P = 0.155). There were no significant differences in grades II - IV acute graft-versus-host disease (aGVHD), grades III - IV aGVHD, chronic GVHD (cGVHD), and the moderate-severe cGVHD between the ATG-F and p-ALG groups (P>0.05).

DISCUSSION

Patients in the ATG-F group functioned significantly better on role-physical (P = 0.006), general health (P = 0.029), and physical component summary (P = 0.009). The estimated overall survival and failure free survival rates at 5 years were 88.5% ± 6.3% vs. 82.4% ± 6.5% (P = 0.515), 84.6% ± 7.1% vs. 79.4% ± 6.9%, respectively (P = 0.579). The infection rates were 61.53% and 47.05%, respectively (P = 0.265).

CONCLUSION

As part of the conditioning regimen, p-ALG achieved a similar efficacy as ATG-F without increasing the incidence of transplantation complications in SAA patients.

Total body irradiation-containing conditioning regimens without antithymocyte globulin in adults with aplastic anemia undergoing umbilical cord blood transplantation

Thus far, there have been no large cohort studies on total body irradiation (TBI)-containing conditioning regimens without antithymocyte globulin (ATG) in adults with aplastic anemia (AA) undergoing umbilical cord blood (UCB) transplantation (UCBT). We retrospectively analyzed 115 adults with idiopathic AA undergoing UCBT using TBI-containing reduced-intensity conditioning (RIC) regimens without ATG between 2000 and 2018 on behalf of the Adult Aplastic Anemia Working Group of the Japanese Society for Hematopoietic Cell Transplantation. We then compared transplantation outcomes between a fludarabine (Flu)- and melphalan (Mel)-based regimen (FM) and a Flu- and cyclophosphamide (Cy)-based regimen (FC). The median patient age at UCBT was 41 years. The median total nucleated cell and total CD34⁺ cell doses in a UCB unit at cryopreservation were 2.5 × 10⁷/kg and 0.7 × 10⁵/kg, respectively. The median follow-up period for survivors was 47 months. The cumulative incidence rate of neutrophil engraftment was 76.5%, and the 4-year overall survival (OS) rate was 64.3%. In multivariate analysis, the covariates that were significantly associated with a higher neutrophil engraftment were total CD34⁺ cell dose in an UCB unit (≥ 0.7 × 10⁵/kg; hazard ratio, 0.57, P = 0.01) and total dose of TBI (4 Gy of TBI; hazard ratio, 0.32, P = 0.01). There was no significant difference in the cumulative incidence of neutrophil engraftment and the 4-year OS between the FM and FC groups. In conclusion, TBI-containing RIC regimens without ATG are suitable for adults with AA undergoing UCBT. There were no significant differences in transplantation outcomes between the FM and FC groups.

Bone marrow transplantation for acquired aplastic anemia: What's new

Bone marrow transplantation is a major therapeutic option for patients with acquired severe aplastic anaemia: improved survival has been achieved in younger patients, thanks to better donor selection, conditioning regimens and graft versus host disease prophylaxis, together with improved supportive care, including diagnosis and treatment of opportunistic infections. This has not been the case for older patients over the age of 40 years. We will discuss transplantation platforms as used for different donor types and we will analyse major breakthroughs of the last years: the combination of Fludarabine and cyclophosphamide as a conditioning regimen, the use of alternative donors including HLA haploidentical related donors and new strategies to prevent acute and chronic graft versus host disease, including post transplantation Cyclophosphamide. These changes extend the option of a bone marrow transplantation for patients who lack an HLA matched donor and appear to improve engraftment and reduce graft versus host disease: whether this will be true for all age groups is currently being investigated.

Acquired severe aplastic anaemia: how medical therapy evolved in the 20th and 21st centuries

The progress in aplastic anaemia (AA) management is one of success. Once an obscure entity resulting in death in most affected can now be successfully treated with either haematopoietic stem cell transplantation (HSCT) or immunosuppressive therapy (IST). The mechanisms that underly the diminution of haematopoietic stem cells (HSCs) are now better elucidated, and include genetics and immunological alterations. Advances in supportive care with better antimicrobials, safer blood products and iron chelation have greatly impacted AA outcomes. Working somewhat 'mysteriously', anti-thymocyte globulin (ATG) forms the base for both HSCT and IST protocols. Efforts to augment immunosuppression potency have not, unfortunately, led to better outcomes. Stimulating HSCs, an often-sought approach, has not been effective historically. The thrombopoietin receptor agonists (Tpo-RA) have been effective in stimulating early HSCs in AA despite the high endogenous Tpo levels. Dosing, timing and best combinations with Tpo-RAs are being defined to improve HSCs expansion in AA with minimal added toxicity. The more comprehensive access and advances in HSCT and IST protocols are likely to benefit AA patients worldwide. The focus of this review will be on the medical treatment advances in AA.

Thrombopoietin Promotes Cell Proliferation and Attenuates Apoptosis of Aplastic Anemia Serum-Treated 32D Cells via Activating STAT3/STAT5 Signaling Pathway and Modulating Apoptosis-Related Mediators

The present study aimed to investigate the effect and possible mechanism of recombinant human thrombopoietin (rhTPO) on mouse 32D cells (a mouse myeloid progenitor cell line) treated with serum from patients with aplastic anemia and to elucidate the potential mechanism of rhTPO in the treatment of aplastic anemia. After treatment with aplastic anemia serum, the apoptotic rate of 32D cells was increased and the proliferation of 32D cells was significantly inhibited. rhTPO reduced the apoptotic rate and promoted the proliferation of 32D cells, while rhTPO failed to restore the cell proliferation of 32D cells from aplastic anemia serum group to the normal level as compared to that from the normal serum group. The phosphorylation level of STAT3 protein was higher, and the phosphorylation level of STAT5 protein was lower in 32D cells from aplastic anemia serum group than that in normal serum group. After rhTPO treatment, the phosphorylation level of STAT3 protein in aplastic anemia serum group was decreased and the phosphorylation level of STAT5 protein was increased. The expression levels of Survivin and Bcl-2 were significantly decreased in 32D cells from aplastic anemia serum group, which were significantly increased after rhTPO treatment. The expression level of Bax protein in 32D cells from the normal serum group after rhTPO treatment was significantly decreased; while the mRNA expression level of Bax was not affected by rhTPO. The expression levels of Bax mRNA and protein were significantly up-regulated in 32D cells from aplastic anemia serum group, which was significantly decreased by rhTPO treatment. In conclusion, our results indicated that aplastic anemia serum impaired proliferative potential and enhanced apoptosis of 32D cells. Further mechanistic studies revealed that rhTPO promoted cell proliferation and attenuated apoptosis of aplastic anemia serum-treated 32D cells via activating STAT3/STAT5 signaling pathway and modulating apoptosis-related mediators.

Evolution of the role of haploidentical stem cell transplantation: past, present, and future

INTRODUCTION

The accessibility to haplo-donors has led to an increase in the number of haplo-HSCT worldwide. A systematic search of the PubMed database between 2000 to present was performed.

AREAS COVERED

In this review, the authors discussed the most used approaches to perform haplo-HSCT and its results: T-cell depletion (TCD, including Perugia platform and its modifications) and T-cell repleted haplo (TCR, including the high-dose post-transplant cyclophosphamide strategy (Baltimore protocol) and the Beijing protocol). The improvements and modifications made to the different strategies have increased the indications of haplo-HSCT, including both malignant and nonmalignant disorders. Focusing on the Baltimore protocol, the authors review the results of the retrospective studies that have compared it to other donor transplants. The limitations of this strategy in terms of toxicity, graft complications, and GVHD are also discussed in detail. Finally, possible approaches to improve the outcomes of TCR haplo-HSCT are presented.

EXPERT OPINION

The recent advances in the field of haplo-HSCT have allowed a large number of patients with incurable diseases to benefit from this procedure despite not having a matched donor. With all available strategies, virtually no patient who needs an allogeneic transplant should be excluded by the absence of a donor.

Haploidentical transplantation and posttransplant cyclophosphamide for treating aplastic anemia patients: a report from the EBMT Severe Aplastic Anemia Working Party

In the absence of an HLA-matched donor, the best treatment for acquired aplastic anemia patients refractory to immunosuppression is unclear. We collected and analyzed data from all acquired aplastic anemia patients who underwent a haploidentical transplantation with posttransplant cyclophosphamide in Europe from 2011 to 2017 (n = 33). The cumulative incidence of neutrophil engraftment was 67% (CI_95%: 51-83%) at D +28 and was unaffected by age group, stem cell source, ATG use, or Baltimore conditioning regimen. The cumulative incidence of grades II-III acute GvHD was 23% at D +100, and limited chronic GvHD was 10% (0-20) at 2 years, without cases of grade IV acute or extensive chronic GvHD. Two-year overall survival was 78% (64-93), and 2-year graft-versus-host disease-free survival was 63% (46-81). In univariate analysis, the 2-year OS was higher among patients who received the Baltimore conditioning regimen (93% (81-100) versus 64% (41-87), p = 0.03), whereas age group, stem cell source, and ATG use had no effect. Our results using unmanipulated haploidentical transplantation and posttransplant cyclophosphamide for treating refractory AA patients are encouraging, but warrant confirmation in a prospective study with a larger number of patients and longer follow-up.

Current status of umbilical cord blood transplantation in children

The first umbilical cord blood (UCB) transplantation was performed 30 years ago. UCB transplantation (UCBT) is now widely used in children with malignant and non-malignant disorders who lack a matched family donor. UCBT affords a lower incidence of graft-versus-host disease compared to alternative stem cell sources, but also presents a slower immune recovery and a high risk of infections if serotherapy is not omitted or targeted within the conditioning regimen. The selection of UCB units with high cell content and good human leucocyte antigen match is essential to improve the outcome. Techniques, such as double UCBT, ex vivo stem cell expansion and intra-bone injection of UCB, have improved cord blood engraftment, but clinical benefit remains to be demonstrated. Cell therapies derived from UCB are under evaluation as potential novel strategies to reduce relapse and viral infections following transplantation. In recent years, improvements within haploidentical transplantation have reduced the overall use of UCBT as an alternative stem cell source; however, each may have its relative merits and disadvantages and tailored use of these alternative stem cell sources may be the optimal approach.

Haploidentical Transplantation with Post-Transplant Cyclophosphamide versus Unrelated Donor Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Hematopoietic stem cell transplantation (HSCT) is the standard treatment for patients with high-risk hematologic malignancies. Only approximately 25% of siblings are HLA-matched, and thus alternative donors-unrelated or haploidentical-are usually the only options available. This meta-analysis aimed to compare haploidentical HSCT with post-transplantation cyclophosphamide and unrelated donor (URD) HSCT. We searched the PubMed and Cochrane databases for pertinent studies indexed between 2008 and 2018. Twenty observational studies (with a total of 1783 haploidentical HSCT recipients and 6077 URD HSCT recipients) were included. Results for overall survival, graft-versus-host disease (GVHD), nonrelapse mortality (NRM), and relapse incidence were pooled. Measures of association used were hazard ratios and risk differences. The median age was 51 years for haploidentical transplant recipients and 52 years for URD transplant recipients. Peripheral blood stem cell (PBSC) grafts were more frequent in the URD transplant recipients (85%) than in the haploidentical transplant recipients (31%). Overall survival was not different between the 2 groups. NRM was lower for haploidentical transplantation. All forms of GVHD (acute grades II-IV and III-IV and moderate, severe, and extensive chronic) were lower with haploidentical donor HSCT. The risk of chronic GVHD was fairly proportional to the differential use of PBSC grafts across studies, however. All included studies were retrospective, representing the major limitation of this meta-analysis. In conclusion, haploidentical HSCT for hematologic malignancies achieved the same overall survival as URD HSCT, with a lower incidence of GVHD and NRM. The increased frequency of PBSC use in the unrelated donor group could partially explain the higher cGVHD rate. Haploidentical transplantation with post-transplantation cyclophosphamide should strongly be considered as the first option for adult patients with hematologic malignancies who do not have matched sibling donors in experienced centers. This systematic review has been registered at PROSPERO (65790).

Indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2019

This is the seventh special EBMT report on the indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders. Our aim is to provide general guidance on transplant indications according to prevailing clinical practice in EBMT countries and centres. In order to inform patient decisions, these recommendations must be considered together with the risk of the disease, the risk of the transplant procedure and the results of non-transplant strategies. In over two decades since the first report, the EBMT indications manuscripts have incorporated changes in transplant practice coming from scientific and technical developments in the field. In this same period, the establishment of JACIE accreditation has promoted high quality and led to improved outcomes of patient and donor care and laboratory performance in transplantation and cellular therapy. An updated report with operating definitions, revised indications and an additional set of data with overall survival at 1 year and non-relapse mortality at day 100 after transplant in the commonest standard-of-care indications is presented. Additional efforts are currently underway to enable EBMT member centres to benchmark their risk-adapted outcomes as part of the Registry upgrade Project 2020 against national and/or international outcome data.