Low-dose post-transplant cyclophosphamide and anti-thymocyte globulin as an effective strategy for GVHD prevention in haploidentical patients

Post-transplant cyclophosphamide or cell selection in haploidentical allogeneic hematopoietic cell transplantation?

BACKGROUND

One major limitation for broader applicability of allogeneic hematopoietic cell transplantation (allo-HCT) in the past was the lack of HLA-matched histocompatible donors. Preclinical mouse studies using T-cell depleted haploidentical grafts led to an increased interest in the use of ex vivo T-cell depleted (TCD) haploidentical allo-HCT. TCD grafts through negative (T-cell depletion) or positive (CD34+ cell selection) techniques have been investigated to reduce the risk of graft-versus-host disease (GVHD) given the known implications of alloreactive T cells. A more practical approach to deplete alloreactive T cells in vivo using high doses of cyclophosphamide after allografting has proved to be feasible in overcoming the HLA barrier. Such approach has extended allo-HCT feasibility to patients for whom donors could not be found in the past. Nowadays, haploidentical donors represent a common donor source for patients in need of an allo-HCT. The broad application of haploidentical donors became possible by understanding the importance of depleting alloreactive donor T cells to facilitate engraftment and reduce incidence and severity of GVHD. These techniques involve ex vivo graft manipulation or in vivo utilization of pharmacologic agents, notably post-transplant cyclophosphamide (PTCy).

DISCUSSION

While acknowledging that no randomized controlled prospective studies have been yet conducted comparing TCD versus PTCy in haploidentical allo-HCT recipients, there are two advantages that would favor the PTCy, namely ease of application and lower cost. However, emerging data on adverse events associated with PTCy including, but not limited to cardiac associated toxicities or increased incidence of post-allograft infections, and others, are important to recognize.

Low-dose anti-thymocyte globulin plus low-dose posttransplant cyclophosphamide-based regimen for prevention of graft-versus-host disease in haploidentical peripheral blood stem cell transplantation for pediatric patients with hematologic malignancies

The low-dose anti-thymocyte globulin (ATG) plus low-dose post transplantation cyclophosphamide (PTCy) -based (low-dose ATG/PTCy-based) regimen had a promising activity in preventing of graft-versus-host disease (GVHD) in adult patients. However, its efficacy in pediatric patients remain to be defined. Here, we presented the findings from 35 pediatric patients undergoing haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) with the new regimen for GVHD prophylaxis. The cumulative incidences (CIs) of grades II-III and III-IV acute GVHD (aGVHD) were 34% (95% CI, 17-48%) and 11% (95% CI, 0-21%) within 180 days post-transplantation, respectively. The CIs of chronic GVHD (cGVHD) and moderate-to-severe cGVHD within 2 years were 26% (95% CI, 7-41%) and 12% (95% CI, 0-25%), respectively. The 2-year probabilities of overall survival, relapse-free survival, and graft-versus-host disease and relapse-free survival were 89% (95% CI, 78-100%), 82% (95% CI, 68-98%) and 59% (95% CI, 43-80%), respectively. The CIs of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivation by day 180 were 37% (95% CI, 19-51%) and 20% (95% CI, 6-32%) respectively. These results strongly advocate for the efficacy of the low-dose ATG/PTCy-based regimen as a robust strategy for GVHD prevention in haplo-PBSCT for pediatric patients.

Efficacy of a modified post-transplant cyclophosphamide regimen for unrelated donor hematopoietic stem cell transplantation in patients with severe aplastic anemia: A prospective study

The aim of the present study was to examine the efficacy of the modified post-transplant cyclophosphamide (PTCy) regimen, which involved reducing the Cy dose to 40 mg on days +3 and +4, in patients with severe aplastic anemia (SAA) subjected to unrelated donor allogeneic hematopoietic stem cell transplantation (URD-HSCT). For this purpose, a prospective single-center trial was conducted and the clinical outcomes were collected from 30 patients with SAA treated with the modified PTCy regimen for URD HSCT. The median time to neutrophil and platelet engraftment was 13 days (range, 11 to 16) and 12 days (range, 5 to 33), respectively. The cumulative incidence of neutrophil and platelet engraftment was 93.1±0.3% and 96.6±0.2%, respectively. The 2-year overall survival (OS) was 97% [95% confidence interval (CI): 90%-100%] and 2-year graft-versus-host disease (GVHD) and rejection-free survival (GRFS) was 93% (95% CI: 85%-100%). The incidence rates of acute GVHD (aGVHD) and chronic GVHD (cGVHD) were 13.8±0.4% and 10.3±0.3%, respectively, and no patients developed grade III-IV aGVHD. However, only one patient developed a moderate extensive cGVHD. The incidence of reconstitution varies among different subsets of immune cells after URD HSCT. Natural killer (NK) cells first recover, followed by CD8+ T and CD19+ B cells, and finally CD4+ T cells. In conclusion, the present study demonstrates that the modified PTCy regimen, with a reduced dose of 40mg on days +3 and +4, may be an effective regimen for URD HSCT in patients with SAA and reduce the occurrence of the GVHD.

Reduced-toxicity conditioning regimen with low dose post-transplantation cyclophosphamide and low-dose anti-thymocyte globulin as graft-versus-host disease prophylaxis for haploidentical stem cell transplantation in older patients

Reduced-toxicity conditioning (RIC) regimens are used for allogeneic hematopoietic stem cell transplantation in older patients. However, successful outcomes are hindered by graft-versus-host disease (GVHD), treatment-related mortality, and relapse, particularly after haploidentical donor hematopoietic stem cell transplantation (HID-HSCT). The aim of this study was to evaluate the effectiveness of an RIC conditioning regimen that included a combination of cyclosporin A, methotrexate (on day + 1), mycophenolate, lower doses of post-transplantation PTCy (40 mg/kg on day + 3), and ATG (7.5 mg/kg) as GVHD prophylaxis prior to haplo-stem cell transplantation (haplo-SCT) in older patients.

METHODS

We retrospectively analyzed outcomes in 55 patients ≥ 55 years of age with hematologic malignancies treated with fludarabine, cytarabine, busulfan, and low-dose cyclophosphamide as the conditioning regimen between January 1, 2019, and November 30, 2023.

RESULTS

Neutrophil engraftment was successful in all patients within 28 days, with 54 patients (98.2%) achieving complete donor chimerism. The cumulative incidence of non-relapse mortality was 0% at 30 days, 7.5% at 100 days, and 19% at 1 year. The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 25% (95%CI, 15-38%), whereas that of grade III-IV aGVHD was 9.1% (95% CI, 3.3-19%). The cumulative incidence of extensive chronic graft-versus-host disease at 1 year was 3.6% (95%CI, 0.66-11%). The cumulative incidences of relapse, overall survival, and GVHD-free/relapse-free survival at 1 year were 9.0%, 71.6%, and 67.1%, respectively.

CONCLUSIONS

An RIC conditioning regimen, including a combination of lower PTCy/ATG as GVHD prophylaxis, followed by haplo-SCT, might be a promising option for appropriately selected older patients.

First-line treatment of severe aplastic anemia: immunosuppressive therapy plus eltrombopag versus haploidentical hematopoietic stem cell transplantation, a multicenter prospective study

Matched-related donor hematopoietic stem cell transplantation (HSCT) remains the preferred first-line option for severe aplastic anemia (SAA) patients aged <40 years even in the era of eltrombopag (EPAG). However, there has not been any direct comparison between immunosuppressive therapy (IST) plus EPAG (IST + EPAG) and haploidentical HSCT (Haplo-HSCT) as first-line therapy. This study prospectively compared the efficacy, safety and health-related quality of life (HRQoL) of Haplo-HSCT (n = 147) and IST + EPAG (n = 121) as first-line treatment for patients with SAA. The results showed that 86.3% of patients in the Haplo-HSCT group and 24.1% of patients in the IST + EPAG group achieved normal complete blood count (CBC) (P < 0.001) after 6 months of treatment. The time to achieve transfusion independence and absolute neutrophil count ≥ 1.0 × 109/L were shorter in the Haplo-HSCT group than in the IST + EPAG group (P < 0.05). In the IST + EPAG and Haplo-HSCT, 3-year overall survival (OS) was 92.4 ± 2.4% and 82.8 ± 3.1% (P = 0.017), whereas 3-year failure-free survival (FFS) was 69.4 ± 4.2% and 81.6 ± 3.2% (P = 0.002), respectively. Similar results were observed in patients with <40 years of age. Among patients with ≥40 years of age, there was no difference in 3-year OS (88.6 ± 4.8% vs. 82.4 ± 8.1%, P = 0.517) between the IST + EPAG and Haplo-HSCT groups, whereas 3-year FFS was lower in the IST + EPAG (58.7 ± 7.5% vs. 82.4 ± 8.1%, P = 0.043). Subgroup analysis for populations aged <40 years indicated that SAA benefited more from IST + EPAG, and very SAA (vSAA) benefited more from Haplo-HSCT. Patients treated with haplo-HSCT scored significantly better in the HRQoL than treated with IST + EPAG (P < 0.0001). Multivariate analysis showed that first-line Haplo-HSCT was associated with normal CBC at 6 months, better FFS and led to a better HRQoL (P < 0.001). In summary, the IST + EPAG achieved better OS for <40 years SAA patients, while the Haplo-HSCT accelerated hematopoietic recovery and HRQoL, achieved better FFS even for those <40 years vSAA and ≥40 years patients.

Recent infection with SARS-CoV-2 in donors was associated with a higher incidence of acute graft-versus-host disease in recipients undergoing allogeneic haematopoietic stem cell transplantation

The global pandemic has resulted in the common occurrence of SARS-CoV-2 infection in the population. In the post-pandemic era, it is imperative to understand the influence of donor SARS-CoV-2 infection on outcomes after allogeneic haematopoietic stem cell transplantation (allo-HSCT). We retrospectively analysed allo-HSCTs from donors with mild SARS-CoV-2 infection or early recovery stage (ERS) (group 1, n = 65) and late recovery stage (group 2, n = 120). Additionally, we included allo-HSCT from donors without prior SARS-CoV-2 infection as group 0 (n = 194). Transplants from donors with different SARS-CoV-2 infection status had comparable primary engraftment and survival rates. However, group 1 had higher incidences of acute graft-versus-host disease (aGvHD), grade II-IV (41.5% vs. 28.1% in group 0 [p = 0.014] and 30.6% in group 2 [p = 0.067]) and grade III-IV (22.2% vs. 9.6% [p = 0.004] in group 0 and 12.2% in group 2 [p = 0.049]). Conversely, the risk of aGvHD in group 2 was similar to that in group 0 (p > 0.5). Multivariable analysis identified group 1 associated with grade II-IV (hazard ratio [HR] 2.307, p = 0.010) and grade III-IV (HR 2.962, p = 0.001) aGvHD, which yielded no significant risk factors for survival. In conclusion, we preliminarily demonstrated donors in the active infection state or ERS of mild SARS-CoV-2 infection were associated with higher incidences of aGvHD in transplants from related donors.

Combination of Anti-thymocyte Globulin with Post-transplant Cyclophosphamide for GVHD Prophylaxis in Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplantation: Systematic Review and Meta-analysis

A new strategy combining anti-thymocyte globulin with post-transplant cyclophosphamide (ATG/PTCy) for graft-versus-host disease (GVHD) prevention was developed. This study aims to perform a systematic review and meta-analysis of studies comparing ATG/PTCy with ATG or PTCy in patients with hematological malignancies undergoing haploidentical hematopoietic stem cell transplantation. Meta-analysis was conducted with Review Manager version 5.4; pooled risk ratios (RRs) and hazard ratios (HRs) were calculated for dichotomous data and time-to-event data, respectively. A fixed-effects model was used if there was no significant heterogeneity. Literature search and study selection identified 14 eligible studies, including both randomized controlled trial and retrospective comparative studies. Different dosage adjustment strategies were applied; the total dose was 2.5-10 mg/kg for ATG and 29-100 mg/kg for PTCy. Meta-analysis results suggest that ATG/PTCy is associated with significantly lower risk of grades II-IV acute GVHD compared with ATG (RR 0.52; 95% CI: 0.41-0.65; P < .00001) and PTCy (RR 0.53; 95% CI: 0.34-0.83; P = .005) without increasing risk of disease relapse. In addition, ATG/PTCy is associated with significantly better overall survival and GVHD-free/relapse-free survival than ATG and PTCy. Future research is required to further establish the benefits of ATG/PTCy and determine the optimal dosage adjustment strategies.

BACKGROUND

Haploidentical stem cell transplantation (haplo-HSCT) is associated with higher incidences of graft-versus-host disease (GVHD). A new strategy combining anti-thymocyte globulin with post-transplant cyclophosphamide (ATG/PTCy) for GVHD prevention has been developed, but its benefits and risks remain unclear.

OBJECTIVE

This study aims to performs a systematic review and meta-analysis of studies comparing ATG/PTCy with ATG or PTCy in patients with hematological malignancies undergoing haplo-HSCT.

STUDY DESIGN

Literature search was performed in databases including Ovid Medline, Embase, Cochrane Library and China Biology Medicine (CBM). Two investigators independently screened eligible studies and extracted data. Meta-analysis was conducted with Review Manager version 5.4; pooled hazard ratios (HRs) for time-to-event outcomes were obtained using a generic inverse-variance method, and pooled risk ratios (RRs) for dichotomous data were obtained using the Mantel-Haenszel method. A fixed-effects model was adopted if there was no significant heterogeneity. The primary outcome is incidence of acute GVHD.

RESULTS

Literature search and study selection identified 14 eligible studies, including both 1 randomized controlled trial and 13 retrospective comparative studies. Different dosage adjustment strategies were applied; the total dose was 2.5-10 mg/kg for ATG and 29-100 mg/kg for PTCy. Meta-analysis results suggest that ATG/PTCy is associated with significantly lower risk of grades II-IV acute GVHD compared with ATG (RR 0.52; 95% CI: 0.41-0.65; P < .00001) and PTCy (RR 0.53; 95% CI: 0.34-0.83; P = .005) without increasing risk of disease relapse. In addition, ATG/PTCy is associated with significantly lower risk of grades III-IV acute GVHD (RR 0.33; 95% CI: 0.23-0.49; P < .00001) and chronic GVHD (RR 0.65; 95% CI: 0.51-0.81; P = .0002) in comparison with ATG. Further analyses suggest that ATG/PTCy is associated with significantly better overall survival and GVHD-free/relapse-free survival than ATG and PTCy, but the risks of cytomegalovirus (RR 1.42; 95% CI: 1.03-1.95; P = .03) and Epstein Barr Virus (RR 3.17; 95% CI: 1.61-6.23; P = .0008) reactivation are higher when compared with PTCy.

CONCLUSIONS

Our results suggest that the combination of ATG with PTCy for GVHD prevention in haplo-HSCT is associated with improved efficacy but higher risk of infection. Future research is required to further establish the benefits and risks of ATG/PTCy and determine the optimal dosage adjustment strategies.

CAR-T Therapy Followed by Hematopoietic Stem Cell Transplantation Can Improve Survival in Children Relapsed/Refractory Philadelphia Chromosome-positive B-cell Acute Lymphoblastic Leukemia

BACKGROUND

Philadelphia chromosome (Ph)-positive B-cell acute lymphoblastic leukemia (ALL) has a high complete remission (CR) rate, but relapse and prolonged measurable residual disease remain serious problems. We sought to describe the CR rate measurable residual disease negative rate and address the results and safety of pediatric patients who underwent after receiving chimeric antigen receptor (CAR) specific for CD19 (CAR-19) followed by hematopoietic stem cell transplantation (HSCT) for the treatment of Ph-positive ALL.

METHODS

A descriptive study was conducted at Peking University People's Hospital from September 2013 to January 2021. 13 patients with relapsed/refractory Ph-positive B-ALL who received CAR-T therapy followed by allo-HSCT were included. We concentrated on the overall patient survival and CR rate.

RESULTS

The median time between CAR-T therapy and allo-HSCT was 58 days. Among all the patients, the CR rate was 100%, the flow cytometry negativity rate was 84.62%, and the BCR-ABL negativity rate was 53.85% at 1 month after CAR-T infusion. All the patients achieved a major molecular response in 6 months after HSCT. After a median follow-up of 45 months, the 3-year OS rate was 66.7%, and the 3-year DFS rate was 61.5%. The 3-year OS rate of patients with BCR-ABL-positive pre-HSCT was significantly lower than that in the BCR-ABL-negative group (40.0% vs. 85.7%, P =0.042). Also, the same trend was observed for the 3-year DFS rate but did not differ significantly (40.0% vs. 75.0%, P =0.233).

CONCLUSIONS

CAR-T therapy followed by allo-HSCT can be a safe and effective treatment for Ph-positive B-ALL pediatric patients.

Optimizing Outcomes in Mismatched Unrelated Donor Allogeneic Transplantation: Post-Transplant Cyclophosphamide's Dual Impact on Graft versus Host Disease Incidence and Overall Survival: Retrospective Analysis on Behalf of Polish Adult Leukemia Group

Allogeneic hematopoietic cell transplantation (allo-HSCT) stands as an effective treatment method for various hematologic malignancies. However, graft-versus-host disease (GvHD), an intricate immunological phenomenon where donor immune cells target recipient tissues, remains a significant challenge, particularly in mismatched unrelated donors (MMUD). Post-transplant cyclophosphamide (PTCy) has emerged as a promising immunosuppressive strategy, revolutionizing haploidentical transplantation and demonstrating promise in MMUD settings. Background/Objectives: This study aimed to evaluate the impact of PTCy on MMUD allo-HSCT outcomes, specifically its effects on GvHD incidence and overall survival, compared to anthitymocyte globulin (ATG). Methods: One hundred seventy-four patients were classified into three groups based on the type of transplantation: PTCy-haplo (114/174; 65.5%), PTCy-MMUD (23/174; 13.2%), and ATG-MMUD (37/174; 21.2%). Results: Our findings showed that PTCy-MMUD significantly reduced acute GvHD occurrence compared to PTCy-haplo and ATG-MMUD approaches (p = 0.006). The delayed onset of acute GvHD in the PTCy-MMUD group suggests a more controlled immune reconstitution, contributing to the lower incidence. Importantly, PTCy-MMUD exhibited enhanced five-year overall survival rates, aligning with the notion that reduced GvHD correlates with improved patient outcomes (p = 0.032). Conclusions: We believe that this study contributes valuable insights into PTCy-MMUD's management, underscoring its potential to significantly reduce GvHD incidence and enhance survival outcomes. Although further investigations and clinical trials are warranted, this research underscores the promising role of PTCy-based GvHD prophylaxis in improving MMUD allo-HCT success.

Dual T-cell depletion with individually tailored anti-thymocyte globulin and attenuated dose of post-transplant cyclophosphamide in haploidentical peripheral stem cell transplantation

This study aimed to assess the efficacy of dual T-cell suppression using individually tailored doses of antithymocyte globulin (ATG) and attenuated dose of post-transplant cyclophosphamide (PTCy) in haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We conducted a retrospective analysis of 78 adults with acute leukemia or myelodysplastic syndrome who underwent haplo-HSCT using intravenous busulfan and fludarabine conditioning. Thirty-two patients received attenuated ATG/PTCy, while 46 patients received ATG (7.5 mg/kg) as GVHD prophylaxis. The 100-day cumulative incidence of grade III-IV (9.7% vs. 32.4%, P = 0.018) acute GVHD, as well as 2-year moderate-severe chronic GVHD (13.9% vs. 43.9%, P = 0.018) in the ATG/PTCy group were significantly lower than those in the ATG group. The 2-year overall survival was comparable between the two groups. However, 2-year GVHD-free, relapse-free survival in the ATG/PTCy group was significantly higher compared to that in the ATG group (38.9% vs. 21.7%, P = 0.021). Moreover, during post-engraftment period, the ATG/PTCy group exhibited lower incidences of life-threatening bacterial (12.5% vs. 37%, P = 0.033) and viral infection (0% vs. 17.4%, P = 0.035) than the ATG group. In conclusion, the combination of individually tailored ATG and low-dose PTCy appears to be a promising strategy in haplo-HSCT.

Hematopoietic Stem-Cell Transplantation: Exploring the Latest Advances and Gaps in Disparities, Psychosocial and Symptom Management Interventions, and Chronic Graft-Versus-Host Disease Care

Although allogeneic hematopoietic cell transplantation (HCT) offers a potential for cure for many patients with advanced hematologic malignancies and bone marrow failure or immunodeficiency syndromes, it is an intensive treatment and accompanied by short- and long-term physical and psychological symptoms requiring specialized care. With substantial advances in therapeutic approaches for HCT and supportive care, HCT survivors experience less morbidity and mortality. However, disparities in both HCT access and outcomes persist, and HCT survivors and their caregivers often lack access to much-needed psychosocial care. Additionally, more medical and psychosocial resources are needed to holistically care for HCT survivors with chronic graft-versus-host disease (GVHD). Hence, this chapter focuses on three areas pertaining to advances and gaps in HCT care: disparities in access to and outcomes of HCT, psychosocial and physical symptom management with supportive care interventions, and GVHD prevention and management.

Case report: Difficult diagnosis of Mycobacterium tuberculosis infection in patients after allogeneic hematopoietic stem cell transplantation: two case reports and a literature review

Background

Mycobacterium tuberculosis (MTB) is a relatively infrequent infection encountered during hematopoietic stem-cell transplantation (HSCT). The identification of MTB following HSCT remains a complex task, with delayed detection and misdiagnosis potentially resulting in unfavorable outcomes. Metagenomic next-generation sequencing (mNGS) represents a novel, highly sensitive, and rapid diagnostic tool in clinical settings for discerning intricate infections and detecting exceedingly rare pathogens.

Methods

With the aid of mNGS, we diagnosed MTB in the lymph nodes and lungs of two patients with hematological diseases following allogeneic peripheral blood hematopoietic stem cell transplantation. Both patients presented with a fever, localized symptoms, and clinical signs. Following inconclusive results from routine tests, impractical biopsy procedures, and unsuccessful responses to empirical treatments, mNGS was employed as a final recourse, revealing DNA fragments of MTB in blood samples.

Results

The diagnoses were ultimately confirmed in conjunction with additional clinical evidence. The application of mNGS in MTB cases after allogeneic HSCT has rarely been reported. The mNGS technique can provide a prompt and highly sensitive indication leading to the definitive diagnosis of MTB in complex post-transplant scenarios.

Outcomes of Antithymocyte Globulin-Post-Transplantation Cyclophosphamide-Cyclosporine-Based versus Antithymocyte Globulin-Based Prophylaxis for 10/10 HLA-Matched Unrelated Donor Allogeneic Hematopoietic Cell Transplantation

In 2015, dual T cell depletion with antithymocyte globulin (ATG) and post-transplantation cyclophosphamide (PTCy) combined with cyclosporine A (CsA) replaced our prior institutional graft-versus-host disease (GVHD) prophylaxis regimen of 4.5 mg/kg ATG, CsA, and mycophenolate mofetil (MMF) (ATG-based) in 10/10 HLA-matched unrelated donor (MUD) peripheral blood allogeneic hematopoietic stem cell transplantation (allo-HCT). The initial ATG dose of 4.5 mg/kg [ATG(4.5)/PTCy] was reduced to 2 mg/kg [ATG(2)/PTCy] in 2018. This study compares the results obtained from 444 adults undergoing MUD allo-HCT at our institution who received ATG(4.5)/PTCy (n = 127) or ATG(2)/PTCy (n = 223) with those who received ATG-based prophylaxis without PTCy (n = 84). The rates of grade II-IV and grade III-IV acute GVHD (aGVHD) at day +100 and moderate/severe chronic GVHD (cGVHD) at 1 year were 35.7%, 21.6%, and 14.7%, respectively, in patients receiving ATG-based prophylaxis without PTCy; 16.5%, 4.9%, and 4.3% in patients receiving ATG(4.5)/PTCy; and 23.3% (P = .004), 8.0% (P < .001), and 14.1% (P =.006) in patients receiving ATG(2)/PTCy. One-year overall survival (OS), nonrelapse mortality (NRM), and GVHD-free relapse-free survival (GRFS) were 69.8%, 25.3%, and 52.0%, respectively, for patients receiving ATG-based prophylaxis without PTCy; 82.7%, 17.3%, and 59.8% for patients receiving ATG(4.5)/PTCy; and 78.3% (P = .446), 14.7% (P = 101), and 56.2% (P = .448) for patients receiving ATG(2)/PTCy. On univariate analyses, the use of ATG(2)/PTCy was associated with a lower risk of NRM (hazard ratio, .54; P = .023) compared with the use of ATG-based prophylaxis without PTCy. ATG(2)/PTCy prophylaxis effectively prevents GVHD and is associated with comparable relapse risk, OS, and GRFS as seen with ATG(4.5)/PTCy and ATG-based prophylaxis without PTCy.

Low dose post-transplant cyclophosphamide and sirolimus induce mixed chimerism with CTLA4-Ig or lymphocyte depletion in an MHC-mismatched murine allotransplantation model

Allogeneic hematopoietic cell transplantation (allo-HCT) offers a curative option for patients with certain non-malignant hematological diseases. High-dose post-transplant cyclophosphamide (PT-Cy) (200 mg/kg) and sirolimus (3 mg/kg), (HiC) synergistically induce stable mixed chimerism. Further, sirolimus and cytotoxic T lymphocyte-associated antigen-4 immunoglobulin (CTLA4-Ig), also known as Abatacept (Aba), promote immune tolerance and allograft survival. Here, in a major histocompatibility complex (MHC)-mismatched allo-HCT murine model, we combined Aba and/or T-cell depleting anti-Thy1.2 (Thy) with a lower dose of PT-Cy (50 mg/kg) and Sirolimus (3 mg/kg), (LoC). While mice in the LoC group showed graft rejection, the addition of Thy to LoC induced similar donor chimerism levels when compared to the HiC group. However, the addition of Aba to LoC led to graft acceptance only in younger mice. When Thy was added to the LoC+Aba setting, graft acceptance was restored in both age groups. Engrafted groups displayed significantly reduced frequencies of recipient-specific interferon-γ-producing T cells as well as an increased frequency in regulatory T cells (Tregs) except in the LoC+Aba group. Splenocytes from engrafted mice showed no proliferation upon restimulation with Balb/c stimulators. Collectively, in combination with Aba or Thy, LoC may be considered to reduce graft rejection in patients who undergo allo-HCT.

Mesenchymal stromal cells plus basiliximab improve the response of steroid-refractory acute graft-versus-host disease as a second-line therapy: a multicentre, randomized, controlled trial

BACKGROUND

For patients with steroid-refractory acute graft-versus-host disease (SR-aGVHD), effective second-line regimens are urgently needed. Mesenchymal stromal cells (MSCs) have been used as salvage regimens for SR-aGVHD in the past. However, clinical trials and an overall understanding of the molecular mechanisms of MSCs combined with basiliximab for SR-aGVHD are limited, especially in haploidentical haemopoietic stem cell transplantation (HID HSCT).

METHODS

The primary endpoint of this multicentre, randomized, controlled trial was the 4-week complete response (CR) rate of SR-aGVHD. A total of 130 patients with SR-aGVHD were assigned in a 1:1 randomization schedule to the MSC group (receiving basiliximab plus MSCs) or control group (receiving basiliximab alone) (NCT04738981).

RESULTS

Most enrolled patients (96.2%) received HID HSCT. The 4-week CR rate of SR-aGVHD in the MSC group was obviously better than that in the control group (83.1% vs. 55.4%, P = 0.001). However, for the overall response rates at week 4, the two groups were comparable. More patients in the control group used ≥ 6 doses of basiliximab (4.6% vs. 20%, P = 0.008). We collected blood samples from 19 consecutive patients and evaluated MSC-derived immunosuppressive cytokines, including HO1, GAL1, GAL9, TNFIA6, PGE2, PDL1, TGF-β and HGF. Compared to the levels before MSC infusion, the HO1 (P = 0.0072) and TGF-β (P = 0.0243) levels increased significantly 1 day after MSC infusion. At 7 days after MSC infusion, the levels of HO1, GAL1, TNFIA6 and TGF-β tended to increase; however, the differences were not statistically significant. Although the 52-week cumulative incidence of cGVHD in the MSC group was comparable to that in the control group, fewer patients in the MSC group developed cGVHD involving ≥3 organs (14.3% vs. 43.6%, P = 0.006). MSCs were well tolerated, no infusion-related adverse events (AEs) occurred and other AEs were also comparable between the two groups. However, patients with malignant haematological diseases in the MSC group had a higher 52-week disease-free survival rate than those in the control group (84.8% vs. 65.9%, P = 0.031).

CONCLUSIONS

For SR-aGVHD after allo-HSCT, especially HID HSCT, the combination of MSCs and basiliximab as the second-line therapy led to significantly better 4-week CR rates than basiliximab alone. The addition of MSCs not only did not increase toxicity but also provided a survival benefit.

The Proportion of Myeloid-derived Suppressor Cells in the Graft as a Potential Predictor of Acute Graft-versus-host Disease in Haploid Allogeneic Hematopoietic Stem Cell Transplantation

Myeloid-derived suppressor cells (MDSC) are powerful immunomodulatory cells that play an important role in infectious and inflammatory disorders, but the correlation between graft MDSC amount and early transplant outcomes remains unknown in allogeneic hematopoietic stem cell transplantation. We collected data from 91 patients with acute leukemia undergoing haploidentical allogeneic hematopoietic stem cell transplantation. The grafts were analyzed in terms of CD34+ cells, CD3+ T cells and subpopulation, and MDSC (HLA-DR -/low CD33 + CD16 - ) by flow cytometry. The cutoff value of the MDSC proportion in the graft on the receiver operating curve was 8.89%, with a sensitivity of 0.833 and specificity of 0.852. Day +100 cumulative incidences of II-IV and III-IV acute graft-versus-host disease (aGVHD) in the low MDSC group were 73.5% and 38.8%, respectively, and that in the high MDSC group were 5.3% and 0%, with a significant difference in incidences of II-IV and III-IV aGVHD ( P <0.001). The overall survival, relapse-free survival, and GVHD-relapse-free survival (GRFS) at 1 year were 66.3% versus 80.5% ( P =0.043), 71.6% versus 71.7% ( P =0.248), and 22.1% versus 62.8% ( P <0.001), respectively. No significant difference in the cumulative incidence of relapse between the 2 groups was observed. Multivariate analysis revealed that higher MDSC proportions were associated with a lower risk of II-IV aGVHD. Graft MDSC proportion exceeding 8.89% was significantly associated with higher overall survival and GRFS. The prophylaxis of antithymocyte globulin+post-transplant cyclophosphamide and higher MDSC proportion in the graft were favorable factors for improving GRFS. In conclusion, graft MDSC proportion may be a significant predictor of aGVHD.

Mesenchymal Stem Cells for Prophylaxis of Chronic Graft-vs-Host Disease After Haploidentical Hematopoietic Stem Cell Transplant: An Open-Label Randomized Clinical Trial

Importance

Chronic graft-vs-host disease (GVHD) limits the long-term benefit of haploidentical hematopoietic stem cell transplant (HSCT). This clinical trial evaluated repeated infusions of umbilical cord mesenchymal stem cells (MSCs) during the early stage (45 days and 100 days) after haplo-HSCT to prevent chronic GVHD.

Objective

To determine whether repeated infusions of MSCs during the early stage after haplo-HSCT decreases the incidence of severe chronic GVHD.

Design, Setting, and Participants

This open-label, multicenter, parallel randomized clinical trial was conducted from April 2016 to January 2022. Eligibility criteria included a diagnosis of acute leukemia and having a haploidentical, suitable related donor for HSCT. The median (range) follow-up time was 39.0 (1.5-67.0) months.

Interventions

The enrolled patients with a haploidentical relative for HSCT received the modified busulfan/cyclophosphamide + antithymocyte globulin modified regimen and standard GVHD prophylaxis. Patients were randomly chosen to receive MSCs (the MSC group) (1 × 106 cells/kg, every 2 weeks, starting from 45 days after transplant, 4 times total) or regular prophylaxis (control group).

Main Outcome and Measure

The cumulative incidence of severe chronic GVHD.

Results

Of 158 patients, 58 (36.7%) were female individuals; the median (range) age for the MSC and control groups was 28 (18-60) years and 28 (18-56) years, respectively. A total of 158 patients were screened, and 148 patients were randomly assigned to the MSC group (n = 74) or control group (n = 74) 1 day before MSCs infusion. The estimated 2-year cumulative incidence of severe chronic GVHD was 5.4% (95% CI, 1.8%-14.0%) in the MSC group and 17.4% (95% CI, 10.1%-28.5%) in the control group (hazard ratio [HR], 0.29; 95% CI, 0.10-0.88; P = .03). There was no difference between the MSC and control groups in the cumulative incidence of leukemia relapse (HR, 1.17; 95% CI, 0.55-2.47; P = .68). The cumulative incidence of stage II to IV acute GVHD in the MSC group was significantly lower than that in the control group (HR, 0.25; 95% CI, 0.09-0.67; P = .01). The MSC group had better GVHD-free and relapse-free survival rates than the control group (HR, 0.62; 95% CI, 0.39-0.98; P = .04).

Conclusions and Relevance

The results of this randomized clinical trial show that early repeated infusions of MSCs decreased the incidence and severity of chronic GVHD, and the incidence and severity of acute GVHD manifested as a better GVHD-free and relapse-free survival rate for patients after haplo-HSCT.

Trial Registration

Chinese Clinical Trial Registry: ChiCTR-IIR-16007806.

When is the best time and grade to start ruxolitinib in corticosteroid-refractory acute graft-versus-host-disease: A multi-center research

OBJECTIVE

Ruxolitinib was recently approved to treat corticosteroid-resistant acute graft-versus-host disease (GvHD). However, it is unknown as to whether starting ruxolitinib at a lower versus higher acute GvHD grade or earlier versus later affected outcomes. This study identified the impact of starting acute GvHD grade and start time after declaring corticosteroid resistance and the effect on complete and overall response rates to ruxolitinib therapy.

METHODS

Retrospective, observational multi-center study. We divided cohorts into starting ruxolitinib ≤ 7 days (N = 45) versus at > 7 days after declaring corticosteroid resistance (N = 24).

RESULTS

In ≤ 7 days cohort complete response (CR) rates at day 28 were 69% (54, 81%) versus 25% (11, 47%; p = .001) in > 7 days cohort, and overall response (OR) rates were 91% (78, 96%) versus 80% (48, 92%; p = .25).

CONCLUSIONS

Our data suggest that starting ruxolitinib in ≤ 7 days of declaring corticosteroid failure regardless of G vHD grade improves complete response rate but not OR rates. Starting ruxolitinib at grade I and within 7 days may get a more significant response.

Epstein-Barr virus reactivation correlates with worse outcomes for patients exposed to hepatitis B virus after haploidentical hematopoietic stem cell transplantation

Hepatitis B virus (HBV)has a high, chronic infection rate in Asian populations, but only few studies have analyzed the effect of Epstein-Barr virus (EBV) or Cytomegalovirus (CMV) reactivation in patients exposed to HBV after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). This study aimed to assess the clinical outcomes of these patients. We conducted a retrospective research including 61 patients exposed to HBV after undergoing haplo-HSCT. The patients were classified into two groups: the CMV reactivation group and no CMV reactivation group. The results were compared between the two groups using the K-W test for continuous variables, Pearson's chi-square test for categorical variables, Kaplan-Meier curves to estimate overall survival (OS) and leukemia-free survival (LFS), and a Cox proportional hazards model to analyze multivariable influences. The 3-year cumulative HBV reactivation rate was 8.2%. The median duration of HBV reactivation was 16 months (16-22 months) after haplo-HSCT. The CMV reactivation group had a higher cumulative incidence of HBV reactivation than the group without CMV reactivation. The EBV reactivation was substantially higher in the CMV reactivation group compared to that in the no CMV reactivation group (37.0% vs.5.9% respectively; P = 0.002). Furthermore, EBV reactivation was a risk factor for 1-year LFS and 1-year OS. Based on our data, EBV reactivation was related to worse outcomes in patients exposed to HBV after haplo-HSCT, whereas CMV reactivation was not.

[Impact of SARS-CoV-2 infection on graft composition and early transplant outcomes following allogeneic hematopoietic stem cell transplantation]

Objective: To assess the feasibility of using donors with novel coronavirus disease 2019 (COVID-19) for allogeneic hematopoietic stem cell transplantation (allo-HSCT) when there are no other available donors and allo-HSCT cannot be delayed or discontinued. Methods: Seventy-one patients with malignant hematological diseases undergoing allo-HSCT between December 8, 2022, and January 10, 2023, were included. Of these, 16 received grafts from donors with mild COVID-19 (D-COVID(+) group) and 55 received grafts from donors without COVID-19 (D-COVID(-) group). The graft compositions were compared between the two groups. Engraftment, acute graft-versus-host disease (aGVHD), overall survival (OS), and relapse were also evaluated. Results: There were no serious side effects or adverse events in the D-COVID(+) group. The mononuclear cell dose and CD34(+) cell dose were comparable between the two groups, and no additional apheresis was required. There were no significant differences in the lymphocyte, monocyte, and T-cell subset doses between the two groups. The median natural killer cell dose in the D-COVID(+) group was significantly higher than that in the D-COVID(-) group (0.69×10(8)/kg vs. 0.53×10(8)/kg, P=0.031). The median follow-up time was 72 (33-104) days. All patients achieved primary engraftment. The 60-day platelet engraftment rates in the D-COVID(+) and D-COVID(-) groups were 100% and (96.4±0.2) %, respectively (P=0.568). There were no significant differences in neutrophil (P=0.309) and platelet (P=0.544) engraftment times. The cumulative incidence of grade 2-4 aGVHD was (37.5±1.6) % vs. (16.4±0.3) % (P=0.062), and of grade 3-4 aGVHD was 25.0% ±1.3% vs. 9.1% ±0.2% (P=0.095) in the D-COVID(+) and D-COVID(-) groups, respectively. The probabilities of 60-day OS were 100% and 98.1% ±1.8% (P=0.522) in the D-COVID(+) and D-COVID(-) groups, respectively. There was no relapse of primary disease during the study period. Conclusion: When allo-HSCT cannot be delayed or discontinued and no other donor is available, a donor with mild COVID-19 should be considered if tolerable. Larger sample sizes and longer follow-up periods are required to validate these results.

Case report: Deep molecular remissions post two separate CD19-targeted chimeric antigen receptor T-cell therapies do not prevent disease from relapsing in Philadelphia chromosome-positive acute lymphoblastic leukemia

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is an aggressive B-cell malignancy. The management of a relapsed Ph+ ALL patient is challenging. Currently, either allogeneic stem cell transplant (allo-SCT) or CD19-targeted chimeric antigen receptor T-cell (CAR T-cell) are usually employed as salvage modalities for a relapsed patient. However, there are few reports concerning cases that had both allo-SCT and multiple CAR T-cell therapies, and the optimal management of such patients is unclear. Here, we report a relapsed Ph+ ALL male who was first salvaged with autologous CAR T-cell therapy, followed by allo-SCT. Unfortunately, he had a second relapse even with complete molecular remission (CMR) response after the first CAR T and allo-SCT. This patient was then successfully salvaged by a second CAR T-cell product that is donor-derived. However, even with a CMR response once again following the second CAR T-cell therapy and prophylactic donor lymphocyte infusion, he experienced a molecular relapse; ponatinib was employed as the subsequent salvage treatment. He achieved a CMR response following ponatinib and was still in remission at the last follow-up. No ABL kinase mutation was detected during the whole course of the disease. This case indicated that a repeated CD19-targeted CAR T-cell treatment is feasible and may be effective in a relapsed Ph+ ALL patient that had previous CAR T-cell and allo-SCT, even though both CAR T-cell have the same construction. However, even with a deep response after each CAR T-cell therapy and allo-SCT, there is still a very small amount of undetectable leukemic cells. The optimal management of Ph+ ALL patients who have a deep response after a second CAR T-cell therapy deserves further exploration.

Combining post-transplant cyclophosphamide with antithymocyte globulin for graft-versus-host disease prophylaxis in hematological malignancies

In search of an ideal partner or alternative to conventional immunosuppressive agents, rabbit anti-thymocyte globulin (ATG) and, more recently, post-transplant cyclophosphamide (PT-Cy) have both emerged as valid and efficient options for preventing graft-versus-host disease (GvHD). To further reduce the risk of GvHD, strategies combining ATG and PT-Cy have recently been investigated. In a haploidentical setting, retrospective studies suggest that combining PT-Cy and ATG may result in a lower incidence of chronic GvHD without increasing the risks of infection or relapse, when compared to PT-Cy without ATG. In haploidentical or unrelated donor settings, adding reduced doses of PT-Cy to ATG may reduce the risk of acute and chronic GvHD and improve survival, particularly GvHD-free, relapse-free survival (GRFS), when compared to ATG without PT-Cy. Overall, the combination of PT-Cy and ATG is a safe and promising approach for patients with hematological malignancies undergoing allogeneic hematopoietic stem cell transplantation (HSCT).

Post-transplantation cyclophosphamide as GVHD prophylaxis in allogenic hematopoietic stem cell transplantation: Recent advances and modification

Allogenic hematopoietic stem cell transplantation (allo-HSCT) is the most important therapeutic option for hematological disorders, although graft-versus-host disease (GVHD) remains the main cause of mortality. Post-transplantation cyclophosphamide (PTCY) induces immune tolerance and is associated with a low incidence of GVHD and non-relapse mortality. Therefore, PTCY has emerged as a safe and effective GVHD prophylaxis in haploidentical transplantation and has been expanded to matched related or unrelated donor and mismatched unrelated donor HSCT. On the basis of current understanding of the mechanisms of PTCY and antithymocyte globulin (ATG) in the prevention of GVHD, growing evidence suggests that the combination of ATG and PTCY could improve allo-HSCT clinical outcomes. Further research will focus on optimizing PTCY regimens by modifying the timing of administration or adding other immunosuppressive agents.

Haploidentical transplants with a G-CSF/ATG-based protocol: Experience from China

Haploidentical donor stem cell transplantation (haplo-SCT) has made great advances in recent decades. The granulocyte colony-stimulating factor (G-CSF)- and antithymocyte globulin (ATG)-based protocol, which is known as the Beijing Protocol, represents one of the current T-cell repletion strategies in haplo-SCT. The key elements of the Beijing Protocol for graft versus host disease (GvHD) prophylaxis include G-CSF inducing T-cell tolerance and altering graft cell components, as well as ATG administration exerting an immunoregulatory effect for intensive prophylaxis. This review will summarize the GvHD incidence, the underlying novel mechanism for GvHD prophylaxis, how to optimize GvHD prophylaxis, and the recent advances of the Beijing Protocol, mainly focusing on the issues of GvHD.

Low-dose anti-thymocyte globulin plus low-dose post-transplant cyclophosphamide-based regimen for prevention of graft-versus-host disease after haploidentical peripheral blood stem cell transplants: a large sample, long-term follow-up retrospective study

Introduction

The novel low-dose anti-thymocyte (ATG, 5 mg/kg) plus low-dose post-transplant cyclophosphamide (PTCy, 50 mg/kg) (low-dose ATG/PTCy)-based regimen had promising activity for prevention of graft-versus-host disease (GVHD) in haploidentical-peripheral blood stem cell transplantation (haplo-PBSCT), but its impacts on long-term outcomes remain to be defined.

Methods

We performed a large sample, long-term follow-up retrospective study to evaluate its efficacy for GVHD prophylaxis.

Results

The study enrolled 260 patients, including 162 with myeloid malignancies and 98 with lymphoid malignancies. The median follow-up time was 27.0 months. For the entire cohort, the cumulative incidences (CIs) of grade II-IV and III-IV acute GVHD (aGVHD) by 180 days were 13.46% (95% CI, 9.64%-17.92%) and 5.77% (95% CI, 3.37%-9.07%); while total and moderate/severe chronic GVHD (cGVHD) by 2 years were 30.97% (95% CI, 25.43%-36.66%) and 18.08% (95% CI, 13.68%-22.98%), respectively. The 2-year overall survival (OS), relapse-free survival (RFS), GVHD-free, relapse-free survival (GRFS), non-relapse mortality (NRM), and CIs of relapse were 60.7% (95% CI, 54.8%-67.10%), 58.1% (95% CI, 52.2%-64.5%), 50.6% (95% CI, 44.8-57.1%), 23.04% (95% CI, 18.06%-28.40%), and 18.09% (95% CI, 14.33%-23.97%, respectively. The 1-year CIs of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivation were 43.46% (95% CI, 37.39%-49.37%) and 18.08% (95% CI, 13.68%-22.98%), respectively. In multivariate analysis, the disease status at transplantation was associated with inferior survivor outcomes for all patients and myeloid and lymphoid malignancies, while cGVHD had superior outcomes for all patients and myeloid malignancies, but not for lymphoid malignancies.

Discussion

The results demonstrated that the novel regimen could effectively prevent the occurrence of aGVHD in haplo-PBSCT.

Novel developments in the prophylaxis and treatment of acute GVHD

Acute graft-versus-host disease (aGVHD) is a major life-threatening complication after allogeneic hematopoietic cell transplant. Traditional standard prophylaxis for aGVHD has included a calcineurin inhibitor plus an antimetabolite, whereas treatment has relied mainly on corticosteroids, followed by multiple nonstandard second-line options. In the past decade, this basic framework has been reshaped by approval of antithymocyte globulin products, the emergence of posttransplant cyclophosphamide, and recent pivotal trials studying abatacept and vedolizumab for GVHD prophylaxis, whereas ruxolitinib was approved for corticosteroid-refractory aGVHD treatment. Because of this progress, routine acute GVHD prophylaxis and treatment practices are starting to shift, and results of ongoing trials are eagerly awaited. Here, we review recent developments in aGVHD prevention and therapy, along with ongoing and future planned clinical trials in this space, outlining what future goals should be and the limitations of current clinical trial designs and end points.

Haploidentical stem cell transplantation with post-transplant cyclophosphamide challenges and outcome from a tertiary care center in Lebanon

This letter describes the experience of the American University of Beirut Medical Center in Lebanon with haploidentical stem cell transplant (haplo-SCT) for hematological malignancies in adult patients. Haplo-SCT made it possible through universal and rapid donor availability for most of the adult patients with leukemia or lymphoma not only in the Middle East but also globally. Moreover, the use of post-transplant cyclophosphamide (PTCy) and reduced intensity conditioning (RIC) regimens when indicated improved the outcome and decreased the toxicity of haploidentical stem cell transplant.RIC regimens also allowed its use in the elderly population. Patients from throughout the Middle East come to our center, the American university of Beirut Medical Center, to receive this transformative type of stem cell transplant. In this paper, we discuss the results of haplo-SCT with PTCy done on adult patients with hematological malignancies in our center from 2015 to 2021. The results are encouraging and show that haplo-SCT should be considered more often in the Middle Eastern countries. The subgroup analysis showed the importance of achieving complete remission of the disease prior to transplant to improve outcomes in our center. There is a paucity of literature on the outcomes of haplo-SCT in the Middle East which may contribute to the limited number of centers that offer this type of SCT. Herein, we aim to fill this gap in the hopes of encouraging the implementation of this potentially curative modality of treatment to a larger extent in the Middle East.

Low-dose post-transplant cyclophosphamide with G-CSF/ATG based haploidentical protocol provides favorable outcomes for SAA patients

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT), as one of the life-saving treatments for severe aplastic anemia (SAA), is widely used because of its great donor availability. Over decades, granulocyte colony-stimulating factor (G-CSF)/antithymocyte globulin (ATG)-based protocol (the so-called Beijing Protocol) has achieved favorable engraftment and survival outcomes. In this study, we modified the conventional Beijing Protocol: the full-dose Cyclophosphamide (Cy) (200 mg/kg in total) was divided into 42.75 mg/kg Cy on day -5 to day -2 and Low dose post-transplant Cy (PTCy) (14.5 mg/kg on days +3 and +4), hoping to reduce the incidence of severe acute graft-versus-host disease (aGVHD) and to guarantee successful and stable engraftment. Here we retrospectively reported and analyzed the data of first 17 patients with SAA who had received haplo-HSCT using this novel regimen between August 2020 and August 2022. The median follow-up was 522 days (range, 138-859 days). No patient developed primary graft failure. Four (23.5%) patients developed grade II bladder toxicity, two (11.8%) patients developed grade II cardiotoxicity. All patients achieved neutrophil and platelet engraftment at median times of 12 days (range, 11-20 days) and14 days (range, 8-36 days). During our follow-up, no patients developed grade III-IV aGVHD. The cumulative incidence of grade II and grade I aGVHD at 100 days was 23.5% (95% CI, 6.8%-49.9%) and 47.1% (95% CI, 23.0%-72.2%). Three patients (17.6%) developed chronic GVHD of skin, mouth, and eyes and all of which were mild. All patients are alive by the end of the follow-up, with a failure-free survival of 100%, which was defined as survival without treatment failures, such as death, graft failure, or relapse rate. The rate of cytomegalovirus (CMV) reactivation was 82.4% (95% CI, 64.3%-100%). The rate of Epstein-Barr virus (EBV) reactivation was 17.6% (95% CI, 3.8%-43.4%). No CMV disease and post-transplantation lymphoproliferative disorder (PTLD) occurred among these patients. In conclusion, the encouraging results of prolonged survival outcomes and reduced incidence of GVHD suggest promising effect of this novel regimen in haplo-HSCT for patients with SAA. Larger-sample prospective clinical trials are needed to confirm the effectiveness of this regimen.

Post-transplantation cyclophosphamide combined with tacrolimus and low-dose post-engraftment anti-thymoglobulin as GVHD prophylaxis for patients undergoing peripheral blood stem cell transplantation from haploidentical family donor: A single center analysis

Introduction

Post-transplantation cyclophosphamide (PT-Cy) use is a recent graft-versus-host disease (GVHD) prophylaxis strategy for patients undergoing allogeneic stem cell transplantation (allo-HSCT). PT-Cy combined with two immunosuppressants is now widely used after haplo-identical (haplo) and HLA-matched peripheral blood stem cell (PBSC) transplantations with promising GVHD and relapsefree survival (GRFS) probabilities. Although appealing, these results may benefit from improvement notably outside matched sibling donor transplantation, and should be investigated in various ethnic populations.

Methods

Therefore, we report our experience of GVHD prophylaxis regimen combining PT-Cy and tacrolimus with addition of post-engraftment low-dose anti-thymocyte globulin (ATG) in allogeneic stem cell transplantation from haplo-identical donors (Haplo). Sixtyseven patients were included in the analysis. All patients received myeloablative or intensified sequential conditioning regimen.

Results

The median follow-up was 521 (range, 10~991) days. The cumulative incidences of 100-day grade II-IV acute GVHD was 14.9±4.4%, and no case of grade III-IV acute GVHD was documented. The cumulative incidences of 2-yearchronic GVHD and moderate-to-severe chronic GVHD were 25.4±5.4% and 11.9±4%, respectively. The non-relapse mortality at day+100 and 2year were 7.5±3.2% and 9.0±3.5%, respectively. The cumulative incidence of relapse at 2year was 16±6.4%. The 2-year probability of DFS and OS were 73.8% (95%CI, 61.5~88.4%) and 72.5% (95% CI, 57.1~92.1%), respectively. The 2-year GRFS was estimated as 63.6% (95%CI, 50.6~80%).

Discussion

Our results suggested that a combination of PT-Cy, tacrolimus, and low-dose post-engraftment ATG was a promising GVHD prophylaxis with low incidence of acute GVHD in the haplo-transplantation setting.

Partially replacing cyclophosphamide with bendamustine in combination with cyclosporine A improves survival and reduces xenogeneic graft-versus-host-disease

Introduction

The use of allogeneic hematopoietic cell transplantation (allo-HCT) for treating hematological disorders is increasing, but the development of graft-versus-host disease (GvHD) remains a major cause of morbidity and mortality. The use of post-transplant cyclophosphamide (CY) has significantly improved outcomes following allo-HCT, but complications of viral reactivation due to delayed immune reconstitution or relapse remain. Other laboratories are evaluating the potential benefit of lowering the dose of CY given post-transplant, whereas our laboratory has been focusing on whether partially replacing CY with another DNA alkylating agent, bendamustine (BEN) may be advantageous in improving outcomes with allo-HCT.

Methods

Here, we utilized a xenogeneic GvHD (xGvHD) model in which immunodeficient NSG mice are infused with human peripheral blood mononuclear cells (PBMCs).

Results

We show that a lower dose of CY (25 mg/kg) given on days +3 and +4 or CY (75 mg/kg) given on only day +3 post-PBMC infusion is not sufficient for improving survival from xGvHD, but can be improved with the addition of BEN (15 mg/kg) on day +4 to day +3 CY (75 mg/kg). CY/BEN treated mice when combined with cyclosporine A (CSA) (10mg/kg daily from days +5 to +18 and thrice weekly thereafter), had improved outcomes over CY/CY +CSA treated mice. Infiltration of GvHD target organs was reduced in both CY/CY and CY/BEN treatment groups versus those receiving no treatment. CY/CY +CSA mice exhibited more severe xGvHD at day 10, marked by decreased serum albumin and increased intestinal permeability. CY/BEN treated mice had reductions in naïve, effector memory and Th17 polarized T cells. RNAseq analysis of splenocytes isolated from CY/CY and CY/BEN treated animals revealed increased gene set enrichment in multiple KEGG pathways related to cell migration, proliferation/differentiation, and inflammatory pathways, among others with CY/BEN treatment.

Conclusion

Together, we illustrate that the use of CY/BEN is safe and shows similar control of xGvHD to CY/CY, but when combined with CSA, survival with CY/BEN is significantly prolonged compared to CY/CY.

Fludarabine and antithymocyte globulin-based conditioning regimen combined with post-transplantation cyclophosphamide for haploidentical allogeneic hematopoietic stem cell transplantation in patients with high-risk acute myeloid leukemia and myelodysplastic syndrome

INTRODUCTION

Relapse and graft-versus-host disease (GVHD) are the important complications influencing mortality for patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). GVHD prophylaxis based on post-transplant cyclophosphamide (PTCy) or antithymocyte globulin (ATG) is widely used in haploidentical HSCT (haplo-HSCT).

OBJECTIVE

We developed a modified intensified conditioning regimen including fludarabine (Flu) and investigated the effect of ATG-PTCy combination on transplant outcomes in high-risk AML and MDS compared with those patients who received only ATG as GVHD prophylaxis.

METHODS

A total of 80 patients with high-risk AML and MDS were divided into two groups and assigned to one-to-one pairing.

RESULTS

The modified ATG-PTCy group had more infused mononuclear cells, CD34-positive cells and CD3-positive cells than those in the ATG group (P < 0.05). The amount of platelet transfusion was higher in the ATG group than the modified ATG-PTCy group [2 (range, 1-6) U vs 2 (range, 1-5) U, P = 0.005]. The median of platelet recovery was better in the modified ATG-PTCy group than in the ATG group (12 days vs 13 days,P = 0.041). The infection rates of bacteria, fungi and virus at 100 days after transplantation were similar in both groups. Compared with the ATG group, individuals who received the modified ATG-PTCy regimen had higher 2-year GVHD- and relapse-free survival(GRFS) [60.0% (95%CI, 44.9-75.1%) vs 34.8% (95%CI, 19.9-49.7%), P = 0.028]; lower 180-day incidence of II-IV acute GVHD (aGVHD) [15.0% (95%CI, 4.0-26.0%) vs 39.8% (95%CI, 23.9-55.7%), P = 0.029]; lower 1-year incidence of moderate to severe chronic GVHD (cGVHD) [2.9% (95%CI, 2.0-3.8%) vs 19.6% (95%CI, 5.3-33.9%), P = 0.039]; and without an increase in the 2-year cumulative incidence of relapse (CIR) [19.5% (95%CI, 6.6-32.4%) vs 30.4% (95%CI, 15.3-45.5%), P = 0.291].

CONCLUSIONS

High-dose stem cells can promote blood cell implantation. The modified ATG-PTCy combination was associated with decreased risk of aGVHD and cGVHD, no increased risk of recurrence, and improved GRFS. It represents an effective strategy for high risk AML and MDS.

Reduced-dose post-transplant cyclophosphamide plus low-dose post-transplant anti-thymocyte globulin as graft-versus-host disease prophylaxis with fludarabine-busulfan-cytarabine conditioning in haploidentical peripheral blood stem cell transplantation: A multicentre, randomized controlled clinical trial

Anti-thymocyte globulin (ATG) or post-transplant cyclophosphamide (PTCy)-based regimens are widely used for graft-versus-host disease (GVHD) prophylaxis in haploidentical haematopoietic stem cell transplantation (haplo-HSCT). To improve the effectiveness of GVHD prophylaxis in haploidentical peripheral blood stem cell transplantation (haplo-PBSCT), we conducted a multicentre, randomized clinical trial to determine the efficacy of reduced-dose PTCy (40 mg/kg/d on days 3 and 4) combined with low-dose post-transplant ATG (2.5 mg/kg on day 8)-based GVHD prophylaxis (reduced-dose PTCy/ATG) with fludarabine-busulfan-cytarabine (FBA) conditioning for patients with haematological malignancies. From 2018 to 2022, 122 patients from four institutions were randomly assigned 1:1 to either a reduced-dose PTCy/ATG or a standard-dose ATG group ('Beijing Protocol', ATG: 10 mg/kg). All patients achieved myeloid engraftment. Cumulative incidences of grade II-IV (11.5% vs 39.3%, p = 0.001) and grade III-IV (6.6% vs 24.6%, p = 0.014) acute GVHD at day 100 were significantly reduced in the reduced-dose PTCy/ATG group. Furthermore, two-year overall survival, disease-free survival and GVHD-free/relapse-free survival were significantly improved in the reduced-dose PTCy/ATG group (75.4% vs 54.1%, p = 0.021; 72.7% vs 55.0%, p = 0.044; 61.3% vs 42.3%, p = 0.022 respectively). Our results demonstrate that the addition of low-dose ATG to reduced-dose PTCy with FBA conditioning is a promising strategy in haplo-PBSCT.

Machine learning algorithm as a prognostic tool for Epstein-Barr virus reactivation after haploidentical hematopoietic stem cell transplantation

Epstein-Barr virus (EBV) reactivation is one of the most important infections after hematopoietic stem cell transplantation (HSCT) using haplo-identical related donors (HID). We aimed to establish a comprehensive model with machine learning, which could predict EBV reactivation after HID HSCT with anti-thymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis. We enrolled 470 consecutive acute leukemia patients, 60% of them (n = 282) randomly selected as a training cohort, the remaining 40% (n = 188) as a validation cohort. The equation was as follows: Probability (EBV reactivation) =   1 1       +       e x p ( - Y ) , where Y = 0.0250 × (age) - 0.3614 × (gender) + 0.0668 × (underlying disease) - 0.6297 × (disease status before HSCT) - 0.0726 × (disease risk index) - 0.0118 × (hematopoietic cell transplantation-specific comorbidity index [HCT-CI] score) + 1.2037 × (human leukocyte antigen disparity) + 0.5347 × (EBV serostatus) + 0.1605 × (conditioning regimen) - 0.2270 × (donor/recipient gender matched) + 0.2304 × (donor/recipient relation) - 0.0170 × (mononuclear cell counts in graft) + 0.0395 × (CD34+ cell count in graft) - 2.4510. The threshold of probability was 0.4623, which separated patients into low- and high-risk groups. The 1-year cumulative incidence of EBV reactivation in the low- and high-risk groups was 11.0% versus 24.5% (P < .001), 10.7% versus 19.3% (P = .046), and 11.4% versus 31.6% (P = .001), respectively, in total, training and validation cohorts. The model could also predict relapse and survival after HID HSCT. We established a comprehensive model that could predict EBV reactivation in HID HSCT recipients using ATG for GVHD prophylaxis.

Low-Dose Anti-Thymocyte Globulin Plus Low-Dose Posttransplant Cyclophosphamide as an Effective Regimen for Prophylaxis of Graft Versus Host Disease After Haploidentical Peripheral Blood Stem Cell Transplantation With Maternal/Collateral Related Donors

Maternal and collateral donors were associated with a higher incidence of graft-versus-host disease (GvHD) after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). A more effective regimen for GvHD prophylaxis after haplo-HSCT with maternal/collateral donors needed to be explored. A retrospective study was performed on 62 patients after haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) with maternal/collateral donors, which included 35 patients with low-dose antithymocyte globulin (ATG) plus low-dose posttransplant cyclophosphamide-based (low-dose ATG/PTCy-based) and 27 with ATG-based regimens for GvHD prophylaxis. The 180-day cumulative incidences (CIs) of grades II-IV and III-IV acute GvHD (aGvHD) were 17.7% and 6.8% in low-dose ATG/PTCy-based group, which were significantly lower than that in ATG-based group (55.4% and 31.9%) (P = 0.003 for grade II-IV and P = 0.007 for III-IV aGvHD). In low-dose ATG/PTCy-based group, the 1-year overall survival (OS) and relapse-free survival (RFS) were 80.0%and 80.4%, which were higher than that in ATG-based group with OS of 59.4% and RFS of 62.0%. In multivariate analysis, the low-dose ATG/PTCy-based regimen significantly reduced the risk of grade II-IV (HR = 0.357; P = 0.049) and grade III-IV aGvHD (HR = 0.190; P = 0.046) as an independent risk factor. The results suggested that the low-dose ATG/PTCy-based regimen could effectively prevent the occurrence of aGvHD after haplo-PBSCT with maternal/collateral donors compared with the ATG-based regimen.

Lower dose of ATG combined with basiliximab for haploidentical hematopoietic stem cell transplantation is associated with effective control of GVHD and less CMV viremia

Currently, the graft-versus-host disease (GVHD) prophylaxis consists of an immunosuppressive therapy mainly based on antithymocyte globulin (ATG) or post-transplant cyclophosphamide (PTCy). GVHD remains a major complication and limitation to successful allogeneic haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We modified the ATG-based GVHD prophylaxis with the addition of basiliximab in the setting of haplo-HSCT and attempted to explore the appropriate dosages. We conducted a retrospective analysis of 239 patients with intermediate- or high-risk hematologic malignancies who received haplo-HSCT with unmanipulated peripheral blood stem cells combined or not with bone marrow. All patients received the same GVHD prophylaxis consisting of the combination of methotrexate, cyclosporine or tacrolimus, mycofenolate-mofetil, and basiliximab with different doses of ATG (5-9mg/kg). With a median time of 11 days (range, 7-40 days), the rate of neutrophil engraftment was 96.65%. The 100-day cumulative incidences (CIs) of grade II-IV and III-IV aGVHD were 15.8 ± 2.5% and 5.0 ± 1.5%, while the 2-year CIs of total cGVHD and extensive cGVHD were 9.8 ± 2.2% and 4.1 ± 1.5%, respectively. The 3-year CIs of treatment-related mortality (TRM), relapse, overall survival (OS), and disease-free survival (DFS) were 14.6 ± 2.6%, 28.1 ± 3.4%, 60.9 ± 3.4%, 57.3 ± 3.4%, respectively. Furthermore, the impact of the reduction of the ATG dose to 6 mg/kg or less in combination with basiliximab on GVHD prevention and transplant outcomes among patients was analyzed. Compared to higher dose of ATG(>6mg/kg), lower dose of ATG (≤6mg/kg) was associated with a significant reduced risk of CMV viremia (52.38% vs 79.35%, P<0.001), while the incidences of aGVHD and cGVHD were similar between the two dose levels. No significant effect was found with regard to the risk of relapse, TRM, and OS. ATG combined with basiliximab could prevent GVHD efficiently and safely. The optimal scheme of using this combined regimen of ATG and basiliximab is that administration of lower dose ATG (≤6mg/kg), which seems to be more appropriate for balancing infection control and GVHD prophylaxis.

Association between haploidentical hematopoietic stem cell transplantation combined with an umbilical cord blood unit and graft-versus-host disease in pediatric patients with acquired severe aplastic anemia

Background:

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) based on granulocyte colony-stimulating factor plus anti-thymocyte regimens (‘Beijing Protocol’) provides a salvage treatment for patients of acquired severe aplastic anemia (SAA) in China. However, graft-versus-host disease (GVHD) is a major impediment of haplo-HSCT due to human leukocyte antigen disparity. Recently, haplo-HSCT combined with umbilical cord blood (UCB) (haplo-cord HSCT) is performed in clinical trials to potentially reduce the risk of severe GVHD. Nevertheless, studies comparing GVHD in pediatric patients receiving haplo and haplo-cord HSCT for SAA are limited.

Objective:

The objective of this study was to investigate the impact of UCB co-infusion on GVHD in pediatric patients receiving haplo-HSCT for SAA.

Design:

We conducted a retrospective study of 91 consecutive SAA children undergoing haploidentical transplantation based on the ‘Beijing Protocol’ with or without co-infusion of UCB in our center.

Methods:

All patients received uniform non-myeloablative conditioning and GVHD prophylaxis. We compared baseline characteristics and transplant outcomes between the haplo (n = 35) and haplo-cord (n = 56) recipients.

Results:

All 91 patients achieved hematopoietic recovery from haploidentical donors, with a higher incidence of peri-engraftment syndrome observed with the haplo-cord group as compared with the haplo group (75.0% versus 48.6%, p = 0.029). Notably, the haplo-cord group showed a lower incidence of II–IV acute GVHD (aGVHD) than the haplo group (16.1% versus 42.9%, p = 0.002). Observed incidences of chronic GVHD (cGVHD) and moderate to severe cGVHD in the haplo-cord group were also lower than that in the haplo group (25.6% versus 51.3%, p = 0.019; 16.2% versus 41.3%, p = 0.016, respectively). Haplo-cord HSCT was identified as the only factor associated with a lower incidence of II–IV aGVHD and cGVHD in multivariate analysis. However, no differences were observed between the two groups for infections and survival outcomes.

Conclusion:

Our data indicated that co-infusion of UCB in ‘Beijing Protocol’-based haplo-HSCT may be effective for reducing the risk of severe GVHD in SAA children.

Abatacept-based Graft-Versus-Host Disease Prophylaxis in Haplo-identical Hematopoietic Cell Transplant in a High-risk Cohort

BACKGROUND

There is insufficient guidance in using posttransplant cyclophosphamide in patients with organ dysfunctions. Abatacept (Aba), a T cell costimulation blockade, has recently been shown to prevent severe acute graft-versus-host disease (GVHD).

OBSERVATION

We report adding Aba as GVHD prophylaxis in 4 pediatrics patients who received haplo-hematopoietic cell transplantation. Two patients had grade 2 acute GVHD and 2 had mild chronic GVHD. All 4 patients are alive with full donor chimerism, and 3 are off immunosuppressants.

CONCLUSION

An Aba-based regimen can result in reliable engraftment and acceptable GVHD when concerns of organ dysfunction prevents the use of posttransplant cyclophosphamide in haplo-hematopoietic cell transplantation.

Should anti-thymocyte globulin be added in post-transplant cyclophosphamide based matched unrelated donor peripheral blood stem cell transplantation for acute myeloid leukemia? A study on behalf of the Acute Leukemia Working Party of the EBMT

In this registry-based study which includes acute myeloid leukemia patients who underwent a matched unrelated donor allogeneic peripheral-blood stem cell transplantation in complete remission and received post-transplant cyclophosphamide (PTCY) as graft-versus-host disease (GvHD) prophylaxis, we compared 421 recipients without anti-thymocyte globulin (ATG) with 151 patients with ATG. The only significant differences between PTCY and PTCY + ATG cohorts were the median year of transplant and the follow-up period (2017 vs 2015 and 19.6 vs 31.1 months, respectively, p < 0.0001). Overall, 2-year survival was 69.9% vs 67.1% in PTCY and PTCY + ATG, respectively, with deaths related to relapse (39% vs 43.5%), infection (21.9% vs 23.9%) or GvHD (17.1% vs 17.4%) not differing between groups. On univariate comparison, a significantly lower rate of extensive chronic GvHD was found when ATG was added (9.9% vs 21%, p = 0.029), a finding which was not confirmed in the multivariate analysis. The Cox-model showed no difference between PTCY + ATG and PTCY alone with respect to acute and chronic GvHD of all grades, non-relapse mortality, relapse, leukemia-free survival, overall survival, and GvHD-free-relapse-free survival between study cohorts. Our results highlight that the addition of ATG in PTCY does not provide any extra benefit in terms of further GvHD reduction, better GRFS or better survival.

Modified combination of anti-thymocyte globulin (ATG) and post-transplant cyclophosphamide (PTCy) as compared with standard ATG protocol in haploidentical peripheral blood stem cell transplantation for acute leukemia

In haploidentical peripheral blood stem cell transplantation (haplo-PBSCT), the combination of anti-thymocyte globulin and post-transplant cyclophosphamide (ATG/PTCy) has a synergistic impact in preventing graft-versus-host disease (GvHD). However, little is known about the long-term consequences of the new combination approach. Our goal is to evaluate the efficacy of ATG/PTCy versus a standard ATG regimen by focusing at long-term outcomes in a more homogeneous group of patients. We retrospectively included 118 adult patients up to 60 years with acute leukemia who underwent haplo-PBSCT at our single institution, following the same myeloablative conditioning regimen. From 2010 to 2020, 78 patients received a modified combination of ATG (2.5 mg/kg/day, on days −3, −2, and −1) and PTCy (40 mg/kg/day on days +3 and +4) compared to 40 patients who had a standard ATG-based regimen (2.5 mg/kg/day from days −4 to −1) from 2008 to 2015. The median follow-up time for all patients was 5.36 years, respectively. The cumulative incidence (CI) of neutrophil and platelet engraftment, as well as CMV reactivation, did not differ statistically between the two groups. The CI of the acute GvHD of grades II–IV and III–IV and extensive chronic GvHD were considerably lower in the ATG/PTCy (34.6%, 8.97%, and 13.63%) than in the ATG cohort (57.5%, 30%, and 38.23%) as validated by multivariable modeling. Additionally, compared to the ATG arm, the ATG/PTCy was a hazard factor associated with a higher risk of relapse (HR = 2.23, p = 0.039). The probability of 5-year overall survival, disease-free survival, and GvHD-free relapse-free survival in the ATG/PTCy group (53.34%, 49.77%, and 36.04%) was comparable with the ATG group (47.5%, 42.5%, and 22.5%), respectively. Our finding suggested that a modified ATG/PTCy combination resulted in a lower risk of acute and chronic GvHD and a higher risk of relapse than the standard ATG-based protocol but had no effect on long-term outcomes. However, certain adjustments in the immunosuppression protocol are warranted to improve the outcome.

Current status and prospects of hematopoietic stem cell transplantation in China

Hematopoietic stem cell transplantation (HSCT) is a highly effective and unique medical procedure for the treatment of most hematological malignancies. The first allogeneic transplantation was performed by E. Donnall Thomas in 1957. Since then, the field has evolved and expanded worldwide. The first successful allogenic HSCT (allo-HSCT) in China was conducted in 1981. Although the development of allo-HSCT in China lagged, China has since made considerable contributions to the process of HSCT worldwide, with more than 10,000 HSCTs performed annually. In particular, haploid HSCT (haplo-HSCT) technology represented in the Beijing Protocol has demonstrated similar efficacy to human leukocyte antigen-matched HSCT and has gradually become the pre-dominant choice for allo-HSCT in China. Currently, the number of haplo-HSCT procedures exceeds 5000 per year, and the Beijing Protocol has been greatly improved by implementing updated individualized strategies for controlling complications, relapse, and infection management. In addition, innovative haplo-HSCT technologies developed by different medical transplantation centers, such as Soochow, Zhejiang, Fujian, Chongqing, and Anhui, have emerged, providing inspiration for the refinement of global practice. This review will focus on the current activity in this field and highlight important trends that are vital in China's allo-HSCT process, examining the current viewpoint and future directions.

Low-dose post-transplant cyclophosphamide with low-dose antithymocyte globulin for prevention of graft-versus-host disease in first complete remission undergoing 10/10 HLA-matched unrelated donor peripheral blood stem cell transplants: a multicentre, randomized controlled trial

The most widely used regimens of graft-versus-host disease (GVHD) prophylaxis in HLA-matched unrelated donor peripheral blood stem cell transplantation (MUD-PBSCT) are based on anti-thymocyte globulin (ATG) or post-transplant cyclophosphamide (PTCy). To improve the efficiency of GVHD prophylaxis, a novel regimen, composed of low-dose PTCy (20 mg/kg on day +3 and +4) and low-dose ATG (6 mg/kg), was evaluted in patients with hematological malignancies ungoing 10/10 HLA MUD-PBSCT in first remission (CR1). In our prospective, multicenter study, 104 patients were randomly assigned one-to-one to low-dose PTCy-ATG (n = 53) or standard-dose ATG (10 mg/kg, n = 51). Both the cumulative incidences (CIs) of grade II-IV acute GVHD (aGVHD) and chronic GVHD (cGVHD) at 2 years in low-dose PTCy-ATG cohort were significantly reduced (24.5% vs. 47.1%; P = 0.017; 14.1% vs. 33.3%; P = 0.013). The CI of non-relapse-mortality (NRM) was much lower (13.2% vs. 34.5%; P = 0.049) and GVHD-free, relapse-free survival (GRFS) was significantly improved at 2 years in low-dose PTCy-ATG arm (67.3% vs 42.3%; P = 0.032). The low-dose PTCy-ATG based GVHD prophylaxis is a promising strategy for patients in CR1 after 10/10 HLA MUD-PBSCT.

Comparison of Outcomes of Haploidentical Peripheral Blood Stem Cell Transplantation Supported by Third-Party Cord Blood Versus Human Leukocyte Antigen-Matched Sibling Peripheral Blood Stem Cell Transplantation in Hematologic Malignancy Patients

Recent studies have shown that haploidentical hematopoietic stem cell transplantation supported by third-party cord blood (haplo-cord-HSCT) results in rapid hematopoietic recovery, low incidences of graft-versus-host disease (GVHD), and relapse of hematologic malignancies. However, few reports on haploidentical peripheral blood stem cell transplantation supported by third-party cord blood (haplo-cord-PBSCT) have been published. To evaluate the outcomes of patients who underwent haplo-cord-PBSCT or human leukocyte antigen (HLA)-matched sibling donor peripheral blood stem cell transplantation (MSD-PBSCT), we retrospectively reviewed the clinical data of patients with hematologic malignancies who underwent haplo-cord-PBSCT (n = 93) or MSD-PBSCT (n = 72) in our hospital from March 2017 to December 2020. In the haplo-cord-PBSCT and MSD-PBSCT groups, the median time for neutrophil and platelet engraftment was 13 vs. 12 days (p = 0.07) and 16 vs. 13 days (p = 0.06), respectively. The 30-day cumulative incidences of neutrophil engraftment were 100.0% and 98.6% (p = 0.12). The 100-day cumulative incidences of platelet engraftment were 96.8% and 98.6% (p = 0.01). The 100-day cumulative incidences of grade II–IV and grade III–IV acute GVHD were 29.1% vs. 23.6% (p = 0.42) and 9.7% vs. 4.2% (p = 0.18). The cumulative incidences of total and moderate/severe chronic GVHD at 1 year were 26.5% vs. 17.4% and 8.1% vs. 4.5%, respectively, and at 3 years were 34.7% vs. 34.3% (p = 0.60) and 13.6% vs. 10.6% (p = 0.49), respectively. The cumulative incidences of relapse at 1 year were 9.3% and 7.2% and at 3 years were 17.0% and 17.0% (p = 0.98). Non-relapse mortality (NRM) at 1 year was 14.6% and 8.6% and at 3 years was 17.4% and 8.6% (p = 0.13) in two groups. The probabilities of overall survival (OS), disease-free survival (DFS), and GVHD-free/relapse-free survival (GRFS) at 1 year were 81.7% vs. 88.6%, 76.1% vs. 84.2%, and 71.7% vs. 79.7%, respectively, and at 3 years were 78.7% vs. 79.0%, 65.6% vs. 74.4%, and 55.5% vs. 63.6%, respectively, in the corresponding group, p > 0.05. In conclusion, for patients with acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) and acute lymphoid leukemia (ALL), haplo-cord-PBSCT results in similar outcomes compared with MSD-PBSCT, and it may be a valid alternative transplantation method.

A comprehensive model to predict severe acute graft-versus-host disease in acute leukemia patients after haploidentical hematopoietic stem cell transplantation

BACKGROUND

Acute graft-versus-host disease (aGVHD) remains the major cause of early mortality after haploidentical related donor (HID) hematopoietic stem cell transplantation (HSCT). We aimed to establish a comprehensive model which could predict severe aGVHD after HID HSCT.

METHODS

Consecutive 470 acute leukemia patients receiving HID HSCT according to the protocol registered at https://clinicaltrials.gov (NCT03756675) were enrolled, 70% of them (n = 335) were randomly selected as training cohort and the remains 30% (n = 135) were used as validation cohort.

RESULTS

The equation was as follows: Probability (grade III-IV aGVHD) = [Formula: see text], where Y = -0.0288 × (age) + 0.7965 × (gender) + 0.8371 × (CD3 + /CD14 + cells ratio in graft) + 0.5829 × (donor/recipient relation) - 0.0089 × (CD8 + cell counts in graft) - 2.9046. The threshold of probability was 0.057392 which helped separate patients into high- and low-risk groups. The 100-day cumulative incidence of grade III-IV aGVHD in the low- and high-risk groups was 4.1% (95% CI 1.9-6.3%) versus 12.8% (95% CI 7.4-18.2%) (P = 0.001), 3.2% (95% CI 1.2-5.1%) versus 10.6% (95% CI 4.7-16.5%) (P = 0.006), and 6.1% (95% CI 1.3-10.9%) versus 19.4% (95% CI 6.3-32.5%) (P = 0.017), respectively, in total, training, and validation cohort. The rates of grade III-IV skin and gut aGVHD in high-risk group were both significantly higher than those of low-risk group. This model could also predict grade II-IV and grade I-IV aGVHD.

CONCLUSIONS

We established a model which could predict the development of severe aGVHD in HID HSCT recipients.

Haploidentical transplantation has a superior graft-versus-leukemia effect than HLA-matched sibling transplantation for Ph- high-risk B-cell acute lymphoblastic leukemia

Background:

Compared with human leukocyte antigen (HLA)-matched sibling donor (MSD) transplantation, it remains unclear whether haploidentical donor (HID) transplantation has a superior graft-versus-leukemia (GVL) effect for Philadelphia-negative (Ph–) high-risk B-cell acute lymphoblastic leukemia (B-ALL). This study aimed to compare the GVL effect between HID and MSD transplantation for Ph– high-risk B-ALL.

Methods:

This study population came from two prospective multicenter trials (NCT01883180, NCT02673008). Immunosuppressant withdrawal and prophylactic or pre-emptive donor lymphocyte infusion (DLI) were administered in patients without active graft-versus-host disease (GVHD) to prevent relapse. All patients with measurable residual disease (MRD) positivity posttransplantation (post-MRD+) or non-remission (NR) pre-transplantation received prophylactic/pre-emptive interventions. The primary endpoint was the incidence of post-MRD+.

Results:

A total of 335 patients with Ph– high-risk B-ALL were enrolled, including 145 and 190, respectively, in the HID and MSD groups. The 3-year cumulative incidence of post-MRD+ was 27.2% (95% confidence interval [CI]: 20.2%–34.7%) and 42.6% (35.5%–49.6%) in the HID and MSD groups (P = 0.003), respectively. A total of 156 patients received DLI, including 60 (41.4%) and 96 (50.5%), respectively, in the HID and MSD groups (P = 0.096). The 3-year cumulative incidence of relapse was 18.6% (95% CI: 12.7%–25.4%) and 25.9% (19.9%–32.3%; P = 0.116) in the two groups, respectively. The 3-year overall survival (OS) was 67.4% (95% CI: 59.1%–74.4%) and 61.6% (54.2%–68.1%; P = 0.382), leukemia-free survival (LFS) was 63.4% (95% CI: 55.0%–70.7%) and 58.2% (50.8%–64.9%; P = 0.429), and GVHD-free/relapse-free survival (GRFS) was 51.7% (95% CI: 43.3%–59.5%) and 37.8% (30.9%–44.6%; P = 0.041), respectively, in the HID and MSD groups.

Conclusion:

HID transplantation has a lower incidence of post-MRD+ than MSD transplantation, suggesting that HID transplantation might have a superior GVL effect than MSD transplantation for Ph– high-risk B-ALL patients.

Trial registration:

ClinicalTrials.gov: NCT01883180, NCT02673008.

A Predicted Model for Refractory/Recurrent Cytomegalovirus Infection in Acute Leukemia Patients After Haploidentical Hematopoietic Stem Cell Transplantation

Objective

We aimed to establish a model that can predict refractory/recurrent cytomegalovirus (CMV) infection after haploidentical donor (HID) hematopoietic stem cell transplantation (HSCT).

Methods

Consecutive acute leukemia patients receiving HID HSCT were enrolled (n = 289). We randomly selected 60% of the entire population (n = 170) as the training cohort, and the remaining 40% comprised the validation cohort (n = 119). Patients were treated according to the protocol registered at https://clinicaltrials.gov (NCT03756675).

Results

The model was as follows: Y = 0.0322 × (age) - 0.0696 × (gender) + 0.5492 × (underlying disease) + 0.0963 × (the cumulative dose of prednisone during pre-engraftment phase) - 0.0771 × (CD34+ cell counts in graft) - 1.2926. The threshold of probability was 0.5243, which helped to separate patients into high- and low-risk groups. In the low- and high-risk groups, the 100-day cumulative incidence of refractory/recurrent CMV was 42.0% [95% confidence interval (CI), 34.7%-49.4%] vs. 63.7% (95% CI, 54.8%-72.6%) (P < 0.001) for total patients and was 50.5% (95% confidence interval (CI), 40.9%-60.1%) vs. 71.0% (95% CI, 59.5%-82.4%) (P = 0.024) for those with acute graft-versus-host disease. It could also predict posttransplant mortality and survival.

Conclusion

We established a comprehensive model that could predict the refractory/recurrent CMV infection after HID HSCT.

Clinical Trial Registration

https://clinicaltrials.gov, identifier NCT03756675.

Addition of a Single Low Dose of Anti T-Lymphocyte Globulin to Post-Transplant Cyclophosphamide after Allogeneic Hematopoietic Stem Cell Transplant: A Pilot Study

Correlation between risk of graft-versus-host disease (GvHD) and CD3⁺ counts within the peripheral blood stem cell graft has recently been reported in the setting of post-transplant cyclophosphamide (PT-Cy). We aimed to investigate the benefit of the addition of a single dose of anti-T lymphocyte globulin (ATLG 5 mg/kg) to PT-Cy in this setting. Starting in 2019, all patients receiving PBSC transplant containing CD3⁺ counts above 300 × 10⁶/kg (study group) received a post-transplant dose of ATLG in addition to standard PT-Cy. The study was designed as a real-life analysis and included all consecutive Hematopoietic Stem Cell Transplantation (HSCT) recipients according to the above-mentioned inclusion criterion (n = 21), excluding cord blood and bone marrow donors. Using a 1:2 matched-pair analysis, we compared the outcomes with a historical population who received PT-Cy only (control group). We found a delayed platelet engraftment (29% vs. 45% at 30 days, p = 0.03) and a non-significant trend toward higher risk of poor graft function (29% vs. 19%, p = 0.52). The addition of ATLG impacted long-term immune reconstitution on the CD4⁺ subsets, but this did not translate into higher rate of relapse or viral infection. Acute GvHD was not significantly impacted, but 1-year cumulative incidence of chronic GvHD was significantly lower in the study group (15% vs. 41%, p = 0.04). Survival outcomes were comparable. In conclusion PT-Cy and ATLG was overall safe and translated into a low rate of chronic GvHD incidence.