Haploidentical haematopoietic stem cell transplantation for acute leukaemia in adults: experience in Europe and the United States. Bone Marrow Transplant. 2008;41:473-481. [PMID: 18176612 DOI: 10.1038/sj.bmt.1705966]

Half a century of healing: celebrating the 50th anniversary of EBMT

EBMT is a non-profit organization with a clear mission: "to save the lives of patients with blood cancers and other life-threatening diseases by advancing the fields of blood and marrow transplantation and cell therapy worldwide through science, education and advocacy". In 1974, EBMT was established by European physicians in St. Moritz to share bone marrow transplantation (BMT) experiences and foster collaboration. Founding members included Jon Van Rood, Bruno Speck, and Eliane Gluckman. By 1989, the group expanded significantly, emphasizing mutual trust and collaboration. EBMT played a crucial role in standardizing transplant procedures, improving outcomes, and expanding access to BMT through donor registries and advancements in HLA mismatched transplants. The organization has grown to include over 7000 members worldwide and has significantly expanded its educational and training initiatives. EBMT continues to adapt to new challenges and advances in the field, including the integration of new therapies and personalized medicine. As of 2024, EBMT remains committed to its mission, embracing diversity and inclusion, and advocating for patient-centered care.

Old drug, new use: Recent advances for G-CSF

Granulocyte colony-stimulating factor (G-CSF), also known as colony-stimulating factor 3 (CSF3), is a proinflammatory cytokine that primarily stimulates the survival, proliferation, differentiation and function of neutrophil granulocyte progenitor cells and mature neutrophils. Over the past years, G-CSF has mainly been used to cure patients with neutropenia and as a part of chemotherapy to induct the remission for refractory/relapse leukemia. Recent studies showed that C-CSF can been used as condition regimens and as a part of preventive methods after allogeneic transplantation to improve the survival of patients and also has immunoregulation, and has promote or inhibit the proliferation of solid tumors. Therefore, in this review, we firstly describe the structure for G-CSF. Then its functions and mechanism were reviewed including the neutrophil mobilization, differentiation, migration, and inhibiting apoptosis of neutrophils, and its immunoregulation. Finally, the clinical applications were further discussed.

Long-term follow-up of haploidentical haematopoietic stem cell transplantation in paediatric patients with high-risk acute myeloid leukaemia: Report from a single centre

Data from 200 children with high-risk acute myeloid leukaemia who underwent their first haploidentical haematopoietic stem cell transplantation (haplo-HSCT) between 2015 and 2021 at our institution were analysed. The 4-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) were 71.9%, 62.3% and 32.4% respectively. The 100-day cumulative incidences of grade II-IV and III-IV acute graft-versus-host disease (aGVHD) were 41.1% and 9.5% respectively. The 4-year cumulative incidence of chronic GVHD (cGVHD) was 56.1%, and that of moderate-to-severe cGVHD was 27.3%. Minimal residual disease (MRD)-positive (MRD+) status pre-HSCT was significantly associated with lower survival and a higher risk of relapse. The 4-year OS, EFS and CIR differed significantly between patients with MRD+ pre-HSCT (n = 97; 63.4%, 51.4% and 41.0% respectively) and those with MRD-negative (MRD-) pre-HSCT (n = 103; 80.5%, 73.3% and 23.8% respectively). Multivariate analysis also revealed that acute megakaryoblastic leukaemia without Down syndrome (non-DS-AMKL) was associated with extremely poor outcomes (hazard ratios and 95% CIs for OS, EFS and CIR: 3.110 (1.430-6.763), 3.145 (1.628-6.074) and 3.250 (1.529-6.910) respectively; p-values were 0.004, 0.001 and 0.002 respectively). Thus, haplo-HSCT can be a therapy option for these patients, and MRD status pre-HSCT significantly affects the outcomes. As patients with non-DS-AMKL have extremely poor outcomes, even with haplo-HSCT, a combination of novel therapies is urgently needed.

The level of Tim-3+CD8+ T cells can serve as a potential marker for evaluating the severity of acute graft-versus-host disease after haplo-PBSCT

Early and accurate diagnosis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation is crucial for the prognosis of patients. This study identified a potential biomarker for the severity of aGVHD after human leukocyte antigen (HLA)-haploidentical peripheral blood hematopoietic stem cell transplantation (haplo-PBSCT). We included 20 healthy subjects and 57 patients who underwent haplo-PBSCT. Of these patients, 22 developed aGVHD after haplo-PBSCT. The results showed that patients with aGVHD had significantly increased levels of Tim-3+/Perforin+/Granzyme B+CD8+ T cells, but significantly decreased Galectin-9. The differences in Galectin-9 and Tim-3+/Granzyme B+CD8+ T cells between grade I-II aGVHD and III-IV aGVHD were also significant. In vitro, the apoptosis of CD8+ T cells from aGVHD patients was significantly increased after Tim-3/Galectin-9 pathway activation, which decreased Granzyme B secretion. As revealed by univariate analysis, the level of Tim-3+CD8+ T cells was a risk factor for severe aGVHD. ROC analysis demonstrated that high levels of Tim-3+CD8+ T cells had a significant diagnostic value for severe aGVHD, with an area under the curve of 0.854 and cut-off value of 14.155%. In conclusion, the binding of Tim-3 with exogenous Galectin-9 can promote apoptosis of CD8+ T cells and affect the secretion of Granzyme B. Tim-3+CD8+ T cells have the potential to serve as immunological markers for assessing the severity of aGVHD after haplo-PBSCT and identifying patients at a higher risk for severe aGVHD.

Haploidentical transplant with posttransplant cyclophosphamide vs matched related and unrelated donor transplant in acute myeloid leukemia and myelodysplastic neoplasm

Hematopoietic cell transplantation from haploidentical donors (haploHCT) has facilitated treatment of AML and MDS by increasing donor availability and became more feasible since the introduction of post-transplant cyclophosphamide (ptCY). In our single-center retrospective analysis including 213 patients with AML or MDS, we compare the outcome of haploHCT (n = 40) with ptCY with HCT from HLA-identical MRD (n = 105) and MUD (n = 68). At 2 years after transplantation, overall survival (OS) after haploHCT was not significantly different (0.59; 95% confidence interval 0.44-0.79) compared to MRD (0.77; 0.67-0.88) and MUD transplantation (0.72; 0.64-0.82, p = 0.51). While progression-free survival (PFS) was also not significantly different (haploHCT: 0.60; 0.46-0.78, MRD: 0.55; 0.44-0.69, MUD: 0.64; 0.55-0.74, p = 0.64), non-relapse mortality (NRM) was significantly higher after haploHCT (0.18; 0.08-0.33) vs. MRD (0.029; 0.005-0.09) and MUD (0.06; 0.02-0.12, p < 0.05). Higher NRM was mainly caused by a higher rate of fatal infections, while deaths related to GvHD or other non-relapse reasons were rare in all groups. As most fatal infections occurred early and were bacterial related, one potential risk factor among many was identified in the significantly longer time to neutrophil engraftment after haploHCT with a median of 16 days (interquartile range; 14.8-20.0) vs. 12 days (10.0-13.0) for MRD and 11 days (10.0-13.0) for MUD (p = 0.01).

Sub-myeloablative Second Transplantations with Haploidentical Donors and Post-Transplant Cyclophosphamide have limited Anti-Leukemic Effects in Pediatric Patients

Pediatric patients with high-risk hematologic malignancies who experience relapse after a prior allogeneic hematopoietic cell transplant (HCT) have an exceedingly poor prognosis. A second allogeneic HCT offers the potential for long-term cure but carries high risks of both subsequent relapse and HCT-related morbidity and mortality. Using haploidentical donors for HCT (haploHCT) can expand the donor pool and potentially enhance the graft-versus-leukemia effect but is accompanied by a risk of graft-versus-host disease (GVHD). The goal of this protocol was to intensify the antileukemia effect of haploHCT for pediatric patients with hematologic malignancies that relapsed after prior allogeneic HCT, while limiting regimen-associated toxicities. This phase II clinical trial evaluated a sub-myeloablative preparative regimen consisting of anti-thymocyte globulin, clofarabine, cytarabine, busulfan, and cyclophosphamide, in combination with plerixafor to sensitize leukemic blasts. Participants received a mobilized peripheral blood unmanipulated haploidentical donor graft with one dose of post-transplant cyclophosphamide as GVHD prophylaxis, followed by natural killer (NK) cell addback. Here we report the clinical outcomes and immune reconstitution of 17 participants treated on the study and 5 additional patients treated on similar single-patient treatment plans. Of the 22 participants analyzed, 12 (55%) had active disease at the time of HCT. The regimen provided robust immune reconstitution, with 21 participants (95%) experiencing neutrophil engraftment at a median of 14 days after HCT. In this high-risk population, the overall survival was 45% (95% confidence interval [CI], 24%-64%), with a 12-month event-free survival of 31% (95% CI, 14%-51%) and cumulative incidence of relapse at 12 months of 50% (95% CI, 27%-69%). Four participants (18%) remain in remission at >5 years follow-up. Expected HCT-related organ-specific toxicities were observed, and 13 participants (59%) experienced acute or chronic GVHD. This intensified but sub-myeloablative regimen, followed by a high-dose unmanipulated haploidentical graft, post-transplantation cyclophosphamide, and NK cell infusion, resulted in adequate immune reconstitution but failed to overcome the elevated risks of relapse and treatment-related morbidity in this high-risk population.

Durable outcomes of double cord blood transplantation in adults with acute lymphoblastic leukemia: high-risk features for early and long-term mortality

Background:

Cord blood transplantation (CBT) has been reported as an acceptable option with comparable outcomes to conventional donors in adults with acute lymphoblastic leukemia (ALL). We aimed to analyze the long-term CBT outcomes and risk factors for early and long-term mortalities.

Methods:

Between 2006 and 2020, 112 patients (median age: 35 years; 62 Ph-negative ALL and 50 Ph-positive ALL) were treated with double CBT. Conditioning regimen consisted of total body irradiation (12 Gy) plus cytarabine (9.0 g/m²) plus fludarabine (150 mg/ m²), and graft-versus-host disease (GVHD) prophylaxis was attempted by administering tacrolimus plus mycophenolate mofetil.

Results:

The median time for neutrophil and platelet recovery was 25 days (range: 5–59 days) and 34 days (range: 7–185 days), respectively. The cumulative incidence of acute GVHD at 1 year was 43.8%, and the incidence of acute GVHD with grades III–IV was 8.9%. The overall cumulative incidence of chronic GVHD was 22.0%, and the incidence of moderate to severe chronic GVHD was 8.5%. After a median follow-up of 60.1 months (range: 5.7–181.3 months), the 5-year cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) were 15.9% and 28.5% (9.7% and 27.2% for CR1), respectively, and the 5-year overall survival (OS) was 57.9% (66.5% for CR1). In multivariate analysis of 88 patients receiving double CBT in CR1, delayed CR1 was related to high CIR, and age older than 40 years was associated with high NRM and early mortality. Unexpectedly, Ph-positive ALL with MRD had a higher NRM and early mortality than Ph-negative ALL and Ph-positive ALL without MRD subgroups, possibly due to delayed neutrophil and platelet recovery.

Conclusion:

Our data suggest that double CBT for adult ALL in CR1 has a greater benefit in younger patients and in patients with Ph-positive ALL without MRD or Ph-negative ALL.

Human herpesvirus 6 reactivation in unmanipulated haploidentical hematopoietic stem cell transplantation predicts the occurrence of grade II to IV acute graft-versus-host disease

BACKGROUND

Human herpesvirus 6 (HHV-6) reactivation is relatively common after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the incidence of HHV-6 reactivation and the clinical outcomes following unmanipulated haploidentical HSCT (haplo-HSCT) remain unknown.

METHOD

We prospectively monitored blood HHV-6 DNA using real-time quantitative polymerase chain reaction weekly until day 100 post unmanipulated haplo-HSCT in patients with hematological malignancies.

RESULTS

From November 2016 to March 2017, 102 patients (58 male and 44 female, median age 25(2-58) years old) were enrolled. Within 100 days post-transplantation, 27 patients (27/136, 19.9%) developed HHV-6 viremia with a median onset time of 14 (7-98) days. The cumulative incidence of HHV-6 reactivation on day 100 post-HSCT was 25.5 ± 4.3% in haplo-HSCT. The median HHV-6 copy number was 1.45 × 10³ (5.48 × 10² -2.00 × 10⁴ ) copies/ml. The HHV-6 viremia duration time was 7 days in 23 patients, 14 days in one patient and 21 days in one patient. In multivariate analysis, prior HHV-6 reactivation was an independent risk factor for grade 2-4 graft-versus-host disease (GVHD). But it did not influence the overall survival (OS)(HR 1.624, 95%CI 0.768-3.432, P = .204), disease-free survival (DFS) (HR 1.640, 95%CI 0.799-3.367, P = .177) and non-relapse mortality (NRM) (HR 1.644, 95%CI 0.670-4.038, P = .278).

CONCLUSION

The reactivation of HHV-6 after unmanipulated haploidentical transplantation predicts the occurrence of grade 2-4 a-GVHD, but it may not influence the overall survival (OS), disease-free survival (DFS) and non-relapse mortality (NRM).

Impact of donor type on long-term graft-versus-host disease-free/relapse-free survival for adult acute lymphoblastic leukemia in first remission

We assessed the impact of donor type on long-term outcomes of allogeneic hematopoietic cell transplantation (HCT) in 440 consecutive adults with acute lymphoblastic leukemia (ALL) in first complete remission (CR1), particularly focusing on the donor type-specific difference in graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS). Donor sources were matched sibling donor (MSD; n = 199), matched unrelated donor (MUD; n = 110), 1-allele-mismatched unrelated donor (1-MMUD; n = 83), and cord blood (CB; n = 48). Cumulative incidence of severe chronic GVHD was 14.8% for MSD-HCT, 30.1% for MUD-HCT, 9.6% for 1-MMUD-HCT, and 4.2% for CBT, respectively (P < 0.001), while no difference was observed in grade III-IV acute GVHD. After a median follow-up of 58.1 months, cumulative incidence of relapse was 26.1% for MSD-HCT, 27.2% for MUD-HCT, 31.2% for 1-MMUD-HCT, and 7.2% for CBT, respectively (P = 0.042). Disease-free survival and overall survival were comparable among all donor sources. However, GRFS for MSD-HCT, MUD-HCT, 1-MMUD-HCT, and CBT was 33.1%, 14.5%, 42.1%, and 50.3%, respectively (P = 0.001). In multivariate analysis, CBT showed a comparable GRFS to MSD-HCT (HR, 0.78; P = 0.290), while MUD-HCT was associated with a poorer GRFS (HR, 1.53; P = 0.002). Given the encouraging GRFS of CBT, our data suggest that CBT remains a valid option for adult ALL in CR1.

Outcomes of hematopoietic stem cell transplantation from unmanipulated haploidentical versus matched sibling donor in patients with acute myeloid leukemia in first complete remission with intermediate or high-risk cytogenetics: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic stem cell transplantation is the optimal care for patients with high-risk or intermediate - acute myeloid leukemia. In patients lacking matched sibling donor, haploidentical donors are an option. We compared outcomes of unmanipulated (Haplo) to matched sibling donor transplant in acute myeloid leukemia patients in first complete remission. Included were intermediate and high-risk acute myeloid leukemia in first complete remission undergoing Haplo and matched sibling donor transplant from 2007-2015, and reported to the ALWP of the EBMT. A propensity score technique was used to confirm results of main analysis: 2 matched sibling donors were matched with 1 Haplo. We identified 2654 pts (Haplo =185; matched sibling donor =2469), 2010 with intermediate acute myeloid leukemia (Haplo=122; matched sibling donor =1888) and 644 with high-risk acute myeloid leukemia (Haplo =63; matched sibling donor =581). Median follow up was 30 (range 1-116) months. In multivariate analysis, in intermediate - acute myeloid leukemia patients, Haplo resulted in lower leukemia-free survival (Hazard Ratio 1.74; P<0.01), overall-survival (HR 1.80; P<0.01) and GvHD-free-relapse-free survival (Hazard Ratio 1.32; P<0.05) and higher graft-versus-host disease (GvHD) non-relapse mortality (Hazard Ratio 3.03; P<0.01) as compared to matched sibling donor. In high-risk acute myeloid leukemia, no differences were found in leukemia-free survival, overall-survival, and GvHD-free- relapse-free survival according to donor type. Higher grade II-IV acute GvHD was observed for Haplo in both high-risk (Hazard Ratio 2.20; P<0.01) and intermediate risk (Hazard Ratio 1.84; P<0.01). A trend for a lower Relapse-Incidence was observed in Haplo among high-risk acute myeloid leukemia (Hazard Ratio 0.56; P=0.06). The propensity score analysis confirmed results. Our results underline that matched sibling donor is the first choice for acute myeloid leukemia patients in first complete remission. On the other hand, results of Haplo transplants are similar to matched sibling donor transplants in acute myeloid leukemia patients with high risk cytogenetics.

Long-term clinical outcomes of hematopoietic cell transplantation for intermediate-to-poor-risk acute myeloid leukemia during first remission according to available donor types

Standard therapy for acute myeloid leukemia (AML) consists of hematopoietic cell transplantation (HCT) including autologous-HCT (AUTO) and allogeneic-HCT from a matched-sibling donor (MSD) or well-matched unrelated donor (WM-URD). When a conventional donor is not available, HCT from a partially-matched (PM)-URD or familial-mismatched donor (FMMD) is typically considered. We analyzed 561 patients with intermediate to poor-risk molecular cytogenetics who underwent transplant from 2002 to 2013 in their first remission. Engraftment was successful in all donor types except five patients who died in aplasia. Disease-free survival (DFS) at 5 years was 61.4% for MSD, 62.1% for WM-URD, 65.3% for FMMD, 44.7% for AUTO and 36.8% for PM-URD. AUTO showed the highest relapse rate (51.0%) compared to MSD (23.5%) and FMMD (18.5%), but showed the lowest 5-year non-relapse mortality (NRM) rate (3.8%). PM-URD showed the highest NRM (29.3%) with more instances of acute graft-vs.-host disease (GVHD) with grade≥III (29.3%), compared to MSD (15.6%) and FMMD (15.7%). In a poor-risk subgroup, the 5-year DFS for FMMD and MSD was 59.8% and 46.7%, respectively, while for AUTO and PM-URD it was 12.6% and 0.0%, respectively, which was caused by a high relapse rate (87.1% in AUTO, 83.3% in PM-URD). In the intermediate-risk subgroup, the 5-year DFS of AUTO (53.9% was not different from the conventional donors in multivariate analysis, presenting a low NRM rate (5.1%). FMMD should be considered prior to PM-URD in intermediate-to-poor-risk AML and GVHD prophylaxis should be intensified when PM-URD is needed. AUTO might be considered for selected patients in the intermediate-risk group.

Impact of cyclosporine-A concentration in T-cell replete haploidentical allogeneic stem cell transplantation

This paper aims to study whether cyclosporine-A (CSA) levels have an impact on the clinical outcome of patients with T-cell replete haploidentical allogeneic hematopoietic stem cell transplantation (allo-HSCT). We analyzed 140 consecutive patients who had been given T-cell replete haploidentical allo-HSCT in our institute to assess the effect of CSA concentration in the early stages of allo-HSCT on clinical outcomes, such as hematopoietic recovery, acute graft vs host disease (aGVHD), infection, disease-free survival (DFS), and overall survival (OS). The median concentrations of CSA in the blood in the 1st, 2nd, 3rd, and 4th week after allo-HSCT were 218, 235, 263, and 270 ng/mL, respectively. Additionally, 46%, 40%, 27%, and 18% of the patients had CSA blood levels below 200 ng/mL during those weeks. In total, 39 patients developed aGVHD (grade II-IV), for a cumulative incidence of 27.8%, at a median of 32 days. Patients having a low CSA concentration (below 200 ng/mL) in the 3rd week had a higher cumulative incidence of grade II-IV aGVHD (P = .02). In addition, multivariate logistic regression analysis showed that low CSA concentration (below 200 ng/mL) in the 3rd week was an independent risk factor of grade II-IV aGVHD (P = .02; odds ratio = 2.66; 95% CI, 1.15-6.17). However, CSA levels during the first 4 weeks did not have a significant impact on the patients' hematopoietic recovery, infection, DFS, and OS. Our data indicated that adequate management of CSA levels during the peri-engraftment period might improve clinical outcomes for those with T-cell replete haploidentical allo-HSCT.

Single Antigen-Mismatched Unrelated Hematopoietic Stem Cell Transplantation Using High-Dose Post-Transplantation Cyclophosphamide Is a Suitable Alternative for Patients Lacking HLA-Matched Donors

The optimal prophylaxis regimen for graft-versus-host disease (GVHD) in the setting of mismatched unrelated donor (MMUD) allogeneic hematopoietic stem cell transplantation (alloHSCT) is not defined. The use of high-dose post-transplant cyclophosphamide (PTCy) in haploidentical transplantation has proven feasible and effective in overcoming the negative impact of HLA disparity on survival. We hypothesized that PTCy could also be effective in the setting of MMUD transplantation. We retrospectively analyzed 86 consecutive adult recipients of alloHSCT in our institution, comparing 2 contemporaneous groups: PTCy MMUD (n = 26) versus matched unrelated donor (MUD) (n = 60). Graft source was primarily peripheral blood (92%). All PTCy MMUD were HLA 7/8 (differences in HLA class I loci in 92% of patients) and received PTCy plus tacrolimus ± mofetil mycophenolate as GVHD prophylaxis. No differences were observed between PTCy MMUD and MUD in the 100-day cumulative incidence of acute GVHD grades II to IV (31% versus 22%, respectively; P = .59) and III to IV (8% versus 10%, P = .67). There was a trend for a lower incidence of moderate to severe chronic GVHD at 1 year after PTCy MMUD in comparison with MUD (22% versus 41%, P = .098). No differences between PTCy MMUD and MUD were found regarding nonrelapse mortality (25% versus 18%, P = .52) or relapse rate (11% versus 19%, P = .18). Progression-free survival and overall survival at 2 years were similar in both cohorts (67% versus 54% [HR, .84; 95% CI, .38 to 1.88; P = .68] and 72% versus 57% [HR, .71; 95% CI, .31 to 1.67; P = .44], respectively). The 2-year cumulative incidence of survival free of moderate to severe chronic GVHD and relapse tended to be higher in the PTCy MMUD group (47% versus 24%; HR, .60; 95% CI, .31 to 1.14; P = .12). We conclude that HLA 7/8 MMUD transplantation using PTCy plus tacrolimus is a suitable alternative for those patients who lack a MUD.

Risk factors in patients undergoing haploidentical hematopoietic stem cell transplantation for high-risk childhood acute leukemia

In the present study, we sought to analyze the risk factors following haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in children with high-risk acute leukemia. We retrospectively reviewed data from 73 children with high-risk leukemia. Univariate and multivariate analyses were performed to evaluate relationships between variables and patient outcomes. The mean time for neutrophil engraftment was significantly shorter in children given a graft with a higher number of nucleated cells (>10.13 × 108/kg vs ≤10.13 × 108/kg: 13.79 ± 2.73 vs 17.71 ± 3.90 days, P < 0.001) and in younger children (≤10 years vs >10 years: 14.21 ± 3.12 vs 17.71 ± 3.90 days, P < 0.001). Time to platelet engraftment was clearly shorter in children given a graft with higher number of nucleated cells (>10.13 × 108/kg vs ≤10.13 × 108/kg: 12.12 ± 8.62 vs 32.1 ± 24.83 days, P < 0.028). Overall survival was 64.6 ± 9.1%, 41.1 ± 10.1%, and 81.6 ± 9.6%, respectively, in children with HR-ALL in CR1, ALL in CR2-4, and AML (P = 0.012). The number of total nucleated cells was significantly associated with transplant-related mortality (TRM). We suggest that outcomes of haplo-HSCT may be improved by increased infusion of nucleated cells.

Low incidence of acute graft-versus-host disease with short-term tacrolimus in haploidentical hematopoietic stem cell transplantation

Although tacrolimus (Tac) has immunosuppressive properties and exhibits promising efficacy against graft-versus-host disease (GVHD), little is known about Tac in the prophylaxis of GVHD after HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT). In a multicenter randomized controlled trial, 174 patients received haplo-HSCT with GVHD prophylaxis involving short-term Tac (from -8days to +30days) or cyclosporine (CsA). The 100day cumulative incidences of acute GVHD (aGVHD) and grade III-IV aGVHD with the short-term Tac regimen and CsA regimen were 29.1 (19.5-38.7)% vs. 50.0(39.6-60.4)% (p=0.005) and 3.6(0.0-7.5)% vs. 13.5(6.1-20.9)% (p=0.027), respectively. There were no significant differences in the incidences of chronic GVHD (cGVHD), relapse and cytomegalovirus infection. Lymphocyte subset analysis showed that T cells decreased to lower levels on the short-term Tac regimen within 3 months of transplantation. The disease-free survival and overall survival on the short-term Tac and CsA regimens were 59.3 (48.9-69.7)% vs. 55.7 (45.3-66.1)% (p=0.696) and 65.1 (55.1-75.1)% vs. 61.4 (51.2-71.6)% (p=0.075), respectively. Our findings indicate that the short-term Tac regimen for GVHD prophylaxis in patients undergoing haplo-HSCT is associated with a low incidence and slight severity of aGVHD and did not increase the incidence of relapse and cytomegalovirus infection.

Genetic barriers in transplantation medicine

The successful of transplantation is determined by the shared human leukocyte antigens (HLAs) and ABO blood group antigens between donor and recipient. In recent years, killer cell receptor [i.e., killer cell immunoglobulin-like receptor (KIR)] and major histocompatibility complex (MHC) class I chain-related gene molecule (i.e., MICA) were also reported as important determinants of transplant compatibility. At present, several different genotyping techniques (e.g., sequence specific primer and sequence based typing) can be used to characterize blood group, HLA, MICA and KIR and loci. These molecular techniques have several advantages because they do not depend on the availability of anti-sera, cellular expression and have greater specificity and accuracy compared with the antibody-antigen based typing. Nonetheless, these molecular techniques have limited capability to capture increasing number of markers which have been demonstrated to determine donor and recipient compatibility. It is now possible to genotype multiple markers and to the extent of a complete sequencing of the human genome using next generation sequencer (NGS). This high throughput genotyping platform has been tested for HLA, and it is expected that NGS will be used to simultaneously genotype a large number of clinically relevant transplantation genes in near future. This is not far from reality due to the bioinformatics support given by the immunogenetics community and the rigorous improvement in NGS methodology. In addition, new developments in immune tolerance based therapy, donor recruitment strategies and bioengineering are expected to provide significant advances in the field of transplantation medicine.

Haploidentical Transplantation Without In Vitro T-Cell Depletion Results in Outcomes Equivalent to Those of Contemporaneous Matched Sibling and Unrelated Donor Transplantation for Acute Leukemia

The aim of the study is to determine whether HLA-haploidentical-related donor (HRD) transplant can achieve equivalent outcomes and have stronger GVL compared to HLA-matched sibling donor (MSD) and HLA-matched unrelated donor (MUD) transplants. A total of 355 consecutive patients with acute leukemia undergoing allogeneic transplant at our single institute between March 2008 and March 2014 were enrolled in this retrospective investigation. Of the 355 patients, 96 cases received HRD, 153 MSD, and 106 MUD transplants. HRD transplant was associated with higher incidences of grade II to IV aGVHD (40.6%) compared with MSD (23.5%, P = 0.002) and MUD transplants (34.0%, P = 0.049), whereas incidences of grade III to IV aGVHD (11.4%, 7.8%, 10.5%, respectively; P = 0.590) and cGVHD (29.5%, 24.0%, 29.5%, respectively; P = 0.538) did not differ among 3 groups. Five-year relapse rates were 19.2%, 26.8%, and 23.0% in 3 groups, respectively (P = 0.419). However, of 206 high-risk patients, the relapse rate in HRD transplant was lower than in MSD transplant (23.8% vs 41.9%, P = 0.026). Multivariate analysis showed that HRD had beneficial impact on relapse (for MSD: P = 0.006). Five-year transplant-related mortality was lower in MSD transplant compared with those in HRD (17.3% vs 26.4%, P = 0.041) and MUD transplants (17.3% vs 24.1%, P = 0.037). Five-year overall survival were 60.4%, 64.6%, and 61.0%, respectively, in HRD, MSD, and MUD groups (P = 0.371); 5-year disease-free survival were 59.6%, 58.8%, and 54.9%, respectively (P = 0.423). Our results suggest that HRD transplant results in outcomes equivalent to MSD and MUD transplants. HRD might carry a superior GVL effect compared to MSD for high-risk patients.

Favorable NK cell activity after haploidentical hematopoietic stem cell transplantation in stage IV relapsed Ewing's sarcoma patients

Natural killer (NK) cell activity has been shown to have potential activity against Ewing's sarcoma (EWS) especially in tumors with low HLA I expression and high NKG2D expression. Two patients with metastatic relapsed and primary metastatic stage IV EWS who had received two courses of high dose chemotherapy with autologous stem cell rescue were transplanted from a haploidentical parental stem cell donor. Patients are alive in ongoing CR for 10.2 and 3.4 years now. Post transplant local second and first relapses were treated successfully in both patients. In vivo IL-2 stimulation not only increased the number and activity of effector cells in one patient but was also associated with severe GvHD. In vitro studies demonstrated high NK cell activity against K562 and relevant activity against EWS cell line A673 post transplant. NK activity was enhanced by cytokine prestimulation as well as by EWS targeting anti-GD2 Ab. Haploidentical hematopoietic stem cell transplantation (HSCT) might contribute to long-term survival by NK cell-mediated effect exerted by donor-derived NK cells. Local tumor recurrence was manageable in both high-risk patients indicating systemic immune control preventing subsequent metastasizing. The efficacy of haploidentical HSCT, cytokine application and tumor targeting antibodies for the use of Ab-dependent cellular cytotoxicity needs evaluation in clinical trials.

Comparison of Three Distinct Prophylactic Agents Against Invasive Fungal Infections in Patients Undergoing Haplo-identical Hematopoietic Stem Cell Transplantation and Post-transplant Cyclophosphamide

Over the past decade, invasive fungal infections (IFIs) have remained an important problem in patients undergoing allogeneic haematopoietic stem cell transplantation (Allo-HSCT). The optimal approach for prophylactic antifungal therapy has yet to bedetermined.

We conducted a retrospective analysis, comparing the safety and efficacy of micafungin 50mg/day vs. fluconazole 400mg/day vs. itraconazole 200mg/day as prophylaxis for adult patients with various haematological diseases receiving haploidentical hematopoietic stem cell transplantation (haplo-HSCT) followed by high-dose cyclophosphamide (PT-Cy).

Overall, 99 patients were identified: 30 patients received micafungin, 50 and 19 patients received itraconazole and fluconazole, respectively. After a median follow-up of 12 months (range: 1–51), proven or probable IFIs were reported in 3 patients (10%) in the micafungin, 5 patients in the itraconazole (10%) and 2 patients (11%) in the fluconazole group (p=0.998). Fewer patients in the micafungin group had invasive aspergillosis (1 [3%] vs. 3 [6%] in the itraconazole vs. 2 [11%] in the fluconazole group, p=0.589). Four patients (13%) in the micafungin group vs 13 (26%) patients in the itraconazole group and 10 (53%) patients in the fluconazole received empirical antifungal therapy (P = 0.19).

No serious adverse events related to treatment were reported by patients, and there was no treatment discontinuation because of drug-related adverse events in both groups.

The present analysis shows that micafungin did better than fluconazole in preventing invasive aspergillosis after transplant in these high-risk hematological diseases, as expected. In addition, micafungin was more effective than itraconazole in preventing all IFI episodes when also considering possible fungal infections. Future prospective studies would shed light on this issue, concerning this increasingly used transplant platform.

Allogeneic hematopoietic stem cell transplantation in adult acute lymphoblastic leukemia: potential benefit of medium-dose etoposide conditioning

The outcomes of adult acute lymphoblastic leukemia (ALL) patients with chemotherapy or autologous hematopoietic stem cell transplantation (HSCT) are unsatisfactory. Therefore, allogeneic (allo) HSCT has been applied to those patients in first complete remission (CR1), and has shown a long-term survival rate of approximately 50 %. In terms of myeloablative conditioning (MAC) regimen, higher dose of cyclophosphamide (CY) and total body irradiation (TBI) (the standard CY + TBI) has been generally applied to allo HSCT. Other MAC regimens such as busulfan-based or etoposide-based regimens have also been used. Among those, medium-dose etoposide (ETP) in addition to the standard CY + TBI conditioning regimen appears to be promising for allo HSCT in adult ALL when transplanted in ALL patients aged under 50 years in CR1 and also in CR2, showing an excellent outcome without increasing relapse or transplant-related mortality (TRM) rates. By contrast, reduced-intensity conditioning (RIC) regimens have also been applied to adult ALL patients and favorable outcomes have been obtained; however, relapse and TRM rates remain high. Therefore, an allo HSCT conditioning regimen which deserves further study for adult ALL patients aged under 50 years in CR1 and CR2 appears to be medium-dose ETP + CY + TBI and RIC is suitable for patients aged over 50 years or for younger patients with comorbid conditions. On the contrary, new therapeutic strategies for adult ALL patients are increasingly utilized with better outcomes; namely, various tyrosine kinase inhibitors for Philadelphia chromosome (Ph)-positive ALL, human leukocyte antigen-haploidentical HSCT, and pediatric-inspired regimens for Ph-negative ALL. Therefore, the optimal treatment modality should be selected considering patient’s age, Ph-positivity, donor availability, risk classification, efficacy, and safety.

Unrelated cord blood compared with haploidentical grafts in patients with hematological malignancies

BACKGROUND

Alternative donors, such as unrelated umbilical cord blood (UCB) and related haploidentical (haplo) donors, are more and more frequently searched for and used for patients who are candidates for allogeneic hematopoietic stem cell transplantation but are without a suitable related or unrelated donor. The aim of the current retrospective study was to compare the outcome of patients after haplo and UCB grafts prepared using a nonmyeloablative conditioning regimen.

METHODS

A total of 150 adult patients with high-risk hematologic diseases who underwent allogeneic hematopoietic stem cell transplantation from alternative donors at 2 centers (Paoli-Calmettes Institute [Marseille, France] and Humanitas Cancer Center [Milan, Italy]) were analyzed. Sixty-nine patients had haplo donors and 81 patients had UCB donors.

RESULTS

The cumulative incidence of nonrecurrence mortality at 1 year was 23% in the UCB group versus 17% in the haplo group (P = .39). The incidence of grade 2 to 4 acute graft-versus-host disease and extensive chronic graft-versus-host disease in the UCB group versus the haplo group was 52% versus 29% (P = .05) and 12% versus 6% (P<.0001), respectively. The overall survival rate at 2 years was 45% in the UCB group (95% confidence interval [95% CI], 34%-56%) versus 69% in the haplo group (95% CI, 58%-80%) (P = .10). The progression-free survival rate at 2 years was 36% in the UCB group (95% CI, 25%-47%) versus 65% in the haplo group (95% CI, 53%-77%) (P = .01).

CONCLUSIONS

The results of the current study suggest that for patients with high-risk hematological diseases without a related or unrelated donor, haploidentical transplants are a promising alternative option that deserves further investigation.

Haploidentical stem cell transplantation for acute leukemia patients who experienced early relapse within one year after the first transplantation

To assess the safety and efficacy of allogeneic stem cell transplantation from haploidentical related donors (haplo-SCT) as 2nd transplantation for patients with early relapsed disease, we retrospectively evaluated 7 consecutive patients (median age, 42 years; range, 29-63 years) who experienced relapse within 1 year of the 1st transplantation and received haplo-SCT as a 2nd transplantation. Among the 7 patients who received haplo-SCT, 2 who were in morphologically complete remission (CR) at transplantation were conditioned with a reduced-intensity regimen, and the 5 non-CR patients were conditioned with a myeloablative regimen. Both conditioning regimens included antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and methylprednisolone. Sustained neutrophil engraftment was achieved in all 7 patients. One patient developed severe acute GVHD. Notably, only 1 patient experienced relapse, and each patient achieved longer CR duration than after the 1st transplantation. Three of the 7 patients died from treatment-related causes: acute GVHD, post-transplantation lymphoproliferative disorder, and bacterial pneumonia. At the time of analysis, the 2-year overall survival rate of these 7 patients was 42.9%. This suggests that use of haploidentical related donors is a viable alternative for 2nd transplantation and should be confirmed in larger cohorts.

T-cell-replete haploidentical HSCT with low-dose anti-T-lymphocyte globulin compared with matched sibling HSCT and unrelated HSCT

We developed an approach of T-cell-replete haploidentical hematopoietic stem cell transplantation (HSCT) with low-dose anti-T-lymphocyte globulin and prospectively compared outcomes of all contemporaneous T-cell-replete HSCT performed at our center using matched sibling donors (MSDs), unrelated donors (URDs), and haploidentical related donors (HRDs). From 2008 to 2013, 90 patients underwent MSD-HSCT, 116 underwent URD-HSCT, and 99 underwent HRD-HSCT. HRDs were associated with higher incidences of grades 2 to 4 (42.4%) and severe acute graft-versus-host disease (17.2%) and nonrelapse mortality (30.5%), compared with MSDs (15.6%, 5.6%, and 4.7%, respectively; P < .05), but were similar to URDs, even fully 10/10 HLA-matched URDs. For high-risk patients, a superior graft-versus-leukemia effect was observed in HRD-HSCT, with 5-year relapse rates of 15.4% in HRD-HSCT, 28.2% in URD-HSCT (P = .07), and 49.9% in MSD-HSCT (P = .002). Furthermore, 5-year disease-free survival rates were not significantly different for patients undergoing transplantation using 3 types of donors, with 63.6%, 58.4%, and 58.3% for MSD, URD, and HRD transplantation, respectively (P = .574). Our data indicate that outcomes after HSCT from suitably matched URDs and HRDs with low-dose anti-T-lymphocyte globulin are similar and that HRD improves outcomes of patients with high-risk leukemia. This trial was registered at www.chictr.org (Chinese Clinical Trial Registry) as #ChiCTR-OCH-12002490.

Experts' considerations on HLA-haploidentical stem cell transplantation

Recently, novel strategies to control graft-versus-host disease and facilitate engraftment have allowed an increasing number of human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (haploHSCT) to be performed. A meeting was convened to review the biological rationale and the clinical results of various T-cell-depleted (TCD) and T-cell-replete (TCR) HLA-haploidentical 'transplant platforms'. The objective of the meeting was to promote discussion and consent among leading researchers in the field on three main crucial issues for haploHSCT: (i) eligibility criteria, (ii) choice of the most suitable donor, and (iii) choice of the most appropriate transplant platform. The experts in attendance agreed that a patient who is eligible for an allogeneic transplant and lacks an HLA-identical sibling or an HLA-matched unrelated donor should be considered for an alternative donor transplant. Together with the experience of the individual center, the most important decision criteria in choosing an alternative donor source should be the rapidity of transplantation so as to avoid disease relapse/progression. The choice of the mismatched donor should be driven by younger age, ABO blood group compatibility, and Cytomegalovirus status. If a TCD transplant is planned, NK-alloreactive donors and/or the mother should be preferred. Prospective comparative studies are needed to establish the relative efficacy of different transplant platforms. However, expertise in stem cell manipulation and in adoptive immunotherapy is essential if a TCD transplant platform is chosen.

Effects of priming with recombinant human granulocyte colony-stimulating factor on conditioning regimen for high-risk acute myeloid leukemia patients undergoing human leukocyte antigen-haploidentical hematopoietic stem cell transplantation: a multicenter randomized controlled study in southwest China

HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is an effective and immediate treatment for high-risk acute myeloid leukemia (HR-AML) patients lacking matched donors. Relapse remains the leading cause of death for HR-AML patients after haplo-HSCT. Accordingly, the prevention of relapse remains a challenge in the treatment of HR-AML. In a multicenter randomized controlled trial in southwestern China, 178 HR-AML patients received haplo-HSCT with conditioning regimens involving recombinant human granulocyte colony-stimulating factor (rhG-CSF) or non-rhG-CSF. The cumulative incidences of relapse and graft-versus-host disease (GVHD), 2-year leukemia-free survival (LFS), and overall survival (OS) were evaluated. HR-AML patients who underwent the priming conditioning regimen with rhG-CSF had a lower relapse rate than those who were treated with non-rhG-CSF (38.2%; 95% confidence interval [CI], 28.1% to 48.3% versus 60.7%, 95% CI, 50.5% to 70.8%; P < .01). The cumulative incidences of acute GVHD, chronic GVHD, transplantation-related toxicity, and infectious complications appeared to be equivalent. In total, 53 patients in the rhG-CSF-priming group and 31 patients in the non-rhG-CSF-priming group were still alive at the median follow-up time of 42 months (range, 24 to 80 months). The 2-year probabilities of LFS and OS in the rhG-CSF-priming and non-rhG-CSF-priming groups were 55.1% (95% CI, 44.7% to 65.4%) versus 32.6% (95% CI, 22.8% to 42.3%) (P < .01) and 59.6% (95% CI, 49.4% to 69.7%) versus 34.8% (95% CI, 24.9% to 44.7%) (P < .01), respectively. Multivariate analyses indicated that the 2-year probability of LFS of patients who achieved complete remission (CR) before transplantation was better than that of patients who did not achieve CR. The 2-year probability of LFS of patients with no M4/M5/M6 subtype was better than that of patients with the M4/M5/M6 subtype in the G-CSF-priming group (67.4%; 95% CI, 53.8% to 80.9% versus 41.9%; 95% CI, 27.1% to 56.6%; P < .05). This study suggests that the rhG-CSF-priming conditioning regimen is an acceptable choice for HR-AML patients, especially for the patients with no M4/M5/M6 subtype who achieved CR before transplantation.

Unmanipulated haploidentical transplants compared with other alternative donors and matched sibling grafts

We studied 459 consecutive patients with hematologic malignancies, median age 44 years (range, 15 to 71 years), who underwent transplantation with grafts from identical sibling donors (SIB; n = 176), matched unrelated donors (MUD; n = 43), mismatched unrelated donors (mmUD; n = 43), unrelated cord blood (UCB; n = 105) or HLA-haploidentical family donors (HAPLO; n = 92). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate in the SIB recipients; antithymocyte globulin for the MUD, mmUD, and UCB recipients; and post-transplantation cyclophosphamide, cyclosporine, and mycophenolate in the HAPLO recipients. Conditioning regimens were mostly myeloablative (69%). Advanced disease phase was more frequent, but not significantly so, in the HAPLO and mmUD groups (P = .08). Acute GVHD grade II-IV was significantly less frequent in the HAPLO, UCB, and MUD groups (14% to 21%) compared with the SIB (31%) and mmUD (42%) groups (P < .001), and there was a trend toward less moderate-severe chronic GVHD in the HAPLO and UCB groups (P = .053). The proportion of patients off cyclosporine at 1 year ranged from 55% for the SIB group to 81% for the HAPLO group (P < .001). Transplantation-related mortality at 2 years was lower in the HAPLO and SIB groups (18% to 24%) compared with the MUD, mmUD, and UCB groups (33% to 35%; P = .10). Relapse rate was comparable in the 5 groups (P = .80). The 4-year actuarial survival was 45% in the SIB group, 43% in the MUD group, 40% in the mmUD group, 34% in the UCB group, and 52% in the HAPLO group (P = .10). In multivariate analysis, advanced disease was a negative predictor of survival (hazard ratio [HR], 2.4; P < .0001), together with a diagnosis of acute leukemia (HR, 1.8; P = .0001); HAPLO grafts were comparable to SIB (P = .80), whereas UCB had inferior survival (P = .03). In conclusion, unmanipulated haploidentical family donor transplants are an additional option for patients lacking a matched sibling donor.

Improving cytomegalovirus-specific T cell reconstitution after haploidentical stem cell transplantation

Cytomegalovirus (CMV) infection and delayed immune reconstitution (IR) remain serious obstacles for successful haploidentical stem cell transplantation (haplo-SCT). CMV-specific IR varied according to whether patients received manipulated/unmanipulated grafts or myeloablative/reduced intensity conditioning. CMV infection commonly occurs following impaired IR of T cell and its subsets. Here, we discuss the factors that influence IR based on currently available evidence. Adoptive transfer of donor T cells to improve CMV-specific IR is discussed. One should choose grafts from CMV-positive donors for transplant into CMV-positive recipients (D+/R+) because this will result in better IR than would grafts from CMV-negative donors (D−/R+). Stem cell source and donor age are other important factors. Posttransplant complications, including graft-versus-host disease and CMV infection, as well as their associated treatments, should also be considered. The effects of varying degrees of HLA disparity and conditioning regimens are more controversial. As many of these factors and strategies are considered in the setting of haplo-SCT, it is anticipated that haplo-SCT will continue to advance, further expanding our understanding of IR and CMV infection.

Total body irradiation and cyclophosphamide plus antithymocyte globulin regimen is well tolerated and promotes stable engraftment as a preparative regimen before T cell-replete haploidentical transplantation for acute leukemia

We compared total body irradiation (TBI, 700 cGy)/cyclophosphamide (Cy, 3.6 g/m(2))/simustine (250 mg/m(2)) plus antithymocyte globulin (ATG) (TBI/Cy plus ATG) with cytarabine (8 g/m(2))/i.v. busulfan (Bu, 9.6 mg/kg)/Cy (3.6 g/m(2))/simustine (250 mg/m(2)) plus ATG (modified Bu/Cy plus ATG) as preparative therapy in T cell-replete haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for acute leukemia. From August 2009 to August 2013, 38 consecutive patients using TBI/Cy plus ATG regimen for T cell-replete haplo-HSCT (TBI group) at our center were eligible, which contained 28 high-risk and 10 standard-risk patients. A nested case-control study was designed. Seventy-seven patients using modified Bu/Cy plus ATG regimen (Bu group) were randomly selected in a 1 to 3:1 ratio matching for age, disease and status, year of HSCT (±2 years), and length of follow-up. Only 1 graft failure occurred in the TBI group. The incidence and time of neutrophil and platelet engraftment were comparable between the 2 groups. Severe grades III/IV graft-versus-host disease was observed in 13.4% of Bu group and only 2.6% of TBI group (P = .083). More toxicity of the liver (37.7% versus 10.5%; P = .002) and more hemorrhagic cystitis occurred in the Bu group (49.3% versus 23.7%, P = .008). Diarrhea was more common in the TBI group (44.7% versus 22.1%; P = .031). No significant differences were found in the 2-year incidences of relapse (26.5% for TBI group versus 32.3% for Bu group, P = .742), 1-year transplant-related mortality (12.6% versus 16.2%, P = .862), 2-year overall survival (60.2% versus 57.0%, P = .937), and 2-year incidence of disease-free survival (57.9% versus 56.6%, P = .845) between the 2 groups. We conclude that the TBI/Cy plus ATG regimen seems to be feasible in T cell-replete haplo-HSCT, which promotes stable engraftment and a lower incidence of liver toxicity and hemorrhagic cystitis. However, longer follow-up is necessary to determine the late relapse rate and late toxicity.

Frequency of allogeneic hematopoietic cell transplantation among patients with high- or intermediate-risk acute myeloid leukemia in first complete remission

PURPOSE

To determine the frequency of allogeneic hematopoietic cell transplantation (HCT) for patients with acute myeloid leukemia (AML) in first complete remission (CR1).

PATIENTS AND METHODS

Between January 1, 2008, and March 1, 2011, 212 newly diagnosed patients with AML received treatment at our center. Ninety-five patients age less than 75 years with intermediate- or high-risk AML achieved a complete remission, and 21 patients achieved a morphologic remission with incomplete blood count recovery.

RESULTS

Seventy-eight (67%; 95% CI, 58% to 76%) of 116 patients received HCT at a median of 2.8 months (range, 0.5 to 19 months) from their CR1 date. The median age was 57 years in both the HCT patient group (range, 18 to 75 years) and the non-HCT patient group (range, 24 to 70 years; P = .514). Between the HCT patients and the non-HCT patients, the mean Eastern Cooperative Oncology Group performance status was 1.1 compared with 1.5, respectively (P = .005), and the average HCT comorbidity score within 60 days of CR1 was 1.7 and 2.1, respectively (P = .68). Twenty-nine (76%) of 38 non-HCT patients were HLA typed, and matched donors were found for 13 of these 29 patients (34% of all non-HCT patients). The most common causes for patients not receiving transplantation in CR1 were early relapse (within 6 months) in 12 patients (32%), poor performance status in eight patients (21%), and physician decision in five patients (13%).

CONCLUSION

HCT can be performed in CR1 in the majority of patients with AML for whom it is currently recommended. The main barriers to HCT were early relapse and poor performance status, highlighting the need for improved therapies for patients with AML of all ages.

The impact of T-cell depletion techniques on the outcome after haploidentical hematopoietic SCT

Several T-cell depletion (TCD) techniques are used for haploidentical hematopoietic SCT (HSCT), but direct comparisons are rare. We therefore studied the effect of in vitro TCD with graft engineering (CD34 selection or CD3/CD19 depletion, 74%) or in vivo TCD using alemtuzumab (26%) on outcome, immune reconstitution and infections after haploidentical HSCT. We performed a retrospective multicenter analysis of 72 haploidentical HSCT in Switzerland. Sixty-seven patients (93%) had neutrophil engraftment. The 1-year OS, TRM and relapse incidence were 48 (36-60)%, 20 (11-33)% and 42 (31-57)%, respectively, without differences among the TCD groups. In vivo TCD caused more profound lymphocyte suppression early after HSCT, whereas immune recovery beyond the second month was comparable between the two groups. Despite anti-infective prophylaxis, most patients experienced post-transplant infectious complications (94%). Patients with in vivo TCD had a higher incidence of CMV reactivations (54% vs 28%, P=0.015), but this did not result in a higher TRM. In conclusion, TCD by graft engineering or alemtuzumab are equally effective for haploidentical HSCT.

T cell depletion in paediatric stem cell transplantation

Haematopoietic stem cell transplantation (HSCT) can be a curative procedure for a growing number of paediatric diseases, but as the indications for HSCT grow, so does the need to find suitable stem cell donors. When the preferred option of a genoidentical sibling donor is not available alternative donors, including unrelated adult or umbilical cord blood donors, or haploidentical related donors may be considered. Outcome following alternative donor HSCT has improved over the past 20 years but graft-versus-host disease (GvHD) remains a significant obstacle. T cell depletion (TCD) for non-genoidentical grafts aims to reduce the morbidity and mortality associated with GvHD, but this intervention has not led directly to improved survival due to delayed immune reconstitution and increased infections, graft rejection and increased rates of disease relapse. Limited data from the paediatric population, however, suggest some encouraging results for children undergoing haploidentical HSCT: a move from positive selection of CD34(+) haematopoietic stem cells towards negative depletion of specific cell subsets in order to retain useful accessory cells within the graft appears to enhance immune reconstitution and improve disease-free survival. Here we review recent paediatric outcome data for T cell-depleted HSCT, explore the role of serotherapy in conditioning regimens and look at future possibilities to improve outcome, including novel allodepletion techniques, suicide gene therapy and pathogen-specific immunotherapy.

Haploidentical stem cell transplantation

The feasibility of stem cell transplantation across the major histocompatibility barrier-as in haploidentical stem cell transplantation-has been proved for some time in several studies. The main limitations include a higher graft failure rate, delayed immune reconstitution after transplantation with high rates of life-threatening infections, a higher incidence of post-transplant lymphoproliferative disease, and severe acute and chronic graft-versus-host disease. In an attempt to reduce the transplant-related morbidity/mortality, several techniques had been evaluated involving conditioning regimen intensity, graft engineering, post-transplant cellular therapy and immunosuppression. This review will describe the current situation. It will also discuss initiatives and strategies to overcome the limitations associated with transplant across the MHC barrier.

Haploidentical, unmanipulated, G-CSF-primed bone marrow transplantation for patients with high-risk hematologic malignancies

Eighty patients with high-risk hematologic malignancies underwent unmanipulated, G-CSF–primed BM transplantation from an haploidentical family donor. Patients were transplanted in first or second complete remission (CR, standard-risk: n =45) or in > second CR or active disease (high-risk: n =35). The same regimen for GVHD prophylaxis was used in all cases. The cumulative incidence (CI) of neutrophil engraftment was 93% 0.1%. The 100-day CIs for II-IV and III-IV grade of acute GVHD were 24% 0.2% and 5% 0.6%, respectively. The 2-year CI of extensive chronic GVHD was 6% 0.1%. The 1-year CI of treatment-related mortality was 36% 0.3%. After a median follow-up of 18 months, 36 of 80 (45%) patients are alive in CR. The 3-year probability of overall and disease-free survival for standard-risk and high-risk patients was 54% 8% and 33% 9% and 44% 8% and 30% 9%, respectively. In multivariate analysis, disease-free survival was significantly better for patients who had standard-risk disease and received transplantations after 2007. We conclude that unmanipulated, G-CSF–primed BM transplantation from haploidentical family donor provides very encouraging results in terms of engraftment rate, incidence of GVHD and survival and represents a feasible, valid alternative for patients with high-risk malignant hematologic diseases, lacking an HLA identical sibling and in need to be urgently transplanted.

KEY POINTS

Haploidentical, unmanipulated, G-CSF-primed bone marrow transplantation. Haploidentical hematopoietic stem cell transplantation for hematologic malignancies.

Allogeneic hematopoietic cell transplantation for MDS: for whom, when and how?

Hematopoietic cell transplantation (HCT) is currently the only treatment with curative potential for patients with myelodysplastic syndrome (MDS). However, treatment-related mortality and relapse have remained major barriers to uniform success. Therefore, important questions remain to be answered, such as whom to transplant, when and how. With reduced intensity conditioning (RIC) regimens, patients in their 70s and patients with comorbid conditions have been transplanted successfully, although the relapse incidence with this approach tends to be increased in comparison to high intensity regimens. Success rates are higher in patients transplanted at an early stage of their disease. Encouraging is the fact, that results with unrelated donors who are HLA-matched by high resolution typing are comparable to those achieved with HLA genotypically identical siblings. The establishment of cord blood as a source of stem cells, and the recent success with HLA-haploidentical related donors will allow the offering of HCT to virtually all patients. Dependent upon disease stage and characteristics, some 25% to 75% of transplanted patients will be cured. While 20%-30% of patients experience chronic medical problems after HCT, 70% report a "good to excellent" quality of life. New studies must focus on further reducing GVHD for all patients and on overcoming high relapse rates in patients with high risk disease.

Timeline, epidemiology, and risk factors for bacterial, fungal, and viral infections in children and adolescents after allogeneic hematopoietic stem cell transplantation

Advances made in the field of hematopoietic stem cell transplantations (HSCT) over the past 20 years may have had an impact on the distribution of posttransplantation infections. We sought to retrospectively analyze the epidemiology and risk factors for bacterial, fungal, and viral infections in children after allogeneic HSCT in a cohort of 759 children who underwent allogeneic HSCT in a single institution between 1990 and 2009. The association between infections and risk factors of interest at 0 to 30 days, 31 to 100 days, and 101 days to 2 years posttransplantation was evaluated using logistic regression. Difference among the subtypes within each category was studied. There were 243 matched-related donors, 239 matched-unrelated donors (MUDs), and 176 haploidentical donor transplantations. Era of transplantation (0-30 days), peripheral blood stem cell product, acute graft-versus-host disease (aGVHD; 31-100 days), and chronic GVHD (cGVHD; 101-730 days) were associated with higher risk for bacterial infections at the respective time periods. Patients with aGVHD (31-100 days), cGVHD, and older age (101-730 days) were at higher risk for fungal infections. Cytomegalovirus (CMV) donor/recipient (D/R) serostatus (0-100 days), era of transplantation, MUD HSCT (31-100 days), and cGVHD (101-730 days), influenced viral infections. Gram-positive outnumbered gram-negative bacterial infections; aspergillosis and candidemia were equally prevalent in all time periods. Haploidentical donor HSCT was not associated with an increased risk of infections. There seems to be a continuum in the timeline of infections posttransplantation, with bacterial, fungal, and viral infections prevalent in all time periods, particularly late after the transplantation, the risk affected by GVHD, CMV, D/R status, product type, older age, and use of unrelated donors.

Haploidentical transplantation using T cell replete peripheral blood stem cells and myeloablative conditioning in patients with high-risk hematologic malignancies who lack conventional donors is well tolerated and produces excellent relapse-free survival: results of a prospective phase II trial

Haploidentical hematopoietic stem cell transplant (HSCT) provides an opportunity for nearly all patients to benefit from HSCT. We conducted a trial of haploidentical T cell replete allografting using a busulfan-based myeloablative preparative regimen, peripheral blood stem cells (PBSCs) as the graft source, and posttransplantation cyclophosphamide (Cy). Eligibility was limited to patients at high risk of relapse after nonmyeloablative haploidentical bone marrow transplant (BMT). Twenty patients were enrolled in the study (11 with relapsed/refractory disease and 9 who underwent transplantation while in remission and considered standard risk). Donor engraftment occurred in all 20 patients with full donor T cell and myeloid chimerism by day +30. The cumulative incidence of grades II-IV and III-IV acute graft-versus-host disease (aGVHD) was 30% and 10%, respectively. The cumulative incidence of chronic GVHD (cGVHD) was 35%. Nonrelapse mortality (NRM) at 100 days and 1 year was 10% for all patients and 0% for standard-risk patients. With a median follow-up of 20 months, the estimated 1-year overall survival (OS) and disease-free survival (DFS) was 69% and 50%, respectively, for all patients, and 88% and 67% for standard-risk patients. Myeloablative haploidentical HSCT is associated with excellent rates of engraftment, GVHD, NRM, and DFS, and is a valid option in patients with high-risk malignancies who lack timely access to a conventional donor.

Allogeneic stem cell transplantation for advanced acute promyelocytic leukemia in the ATRA and ATO era

The role of allogeneic stem cell transplant in advanced acute promyelocytic leukemia patients who received standard first- and second-line therapy is still unknown. We report the outcome of 31 acute promyelocytic leukemia patients (median age 39 years) who underwent allogeneic transplant in second remission (n=15) or beyond (n=16). Sixteen patients were real-time polymerase chain reaction positive and 15 negative for PML/RARA pre-transplant. The 4-year overall survival was 62% and 31% for patients transplanted in second remission and beyond, respectively (P=0.05), and 64% and 27% for patients with pre-transplant negative and positive real-time polymerase chain reaction, respectively (P=0.03). The 4-year cumulative incidence of relapse was 32% and 44% for patients transplanted in second remission and beyond, respectively (P=0.37), and 30% and 47% for patients transplanted with negative and positive real-time polymerase chain reaction, respectively (P=0.30). Transplant-related mortality was 19.6%. In conclusion, allogeneic transplant is effective in advanced acute promyelocytic leukemia in the all-trans-retinoic acid and arsenic trioxide era, and should be considered once relapse is diagnosed.

The superiority of haploidentical related stem cell transplantation over chemotherapy alone as postremission treatment for patients with intermediate- or high-risk acute myeloid leukemia in first complete remission

We report the results of a prospective, patient self-selected study evaluating whether haploidentical related donor stem cell transplantation (HRD-HSCT) is superior to chemotherapy alone as postremission treatment for patients with intermediate- or high-risk acute myeloid leukemia (AML) in first complete remission (CR1). Among totally 419 newly diagnosed AML patients, 132 patients with intermediate- and high-risk cytogenetics achieved CR1 and received chemotherapy alone (n = 74) or HSCT (n = 58) as postremission treatment. The cumulative incidence of relapse at 4 years was 37.5% ± 4.5%. Overall survival (OS) and disease-free survival (DFS) at 4 years were 64.5% ± 5.1% and 55.6% ± 5.0%, respectively. The cumulative incident of relapse for the HRD-HSCT group was significantly lower than that for the chemotherapy-alone group (12.0% ± 4.6% vs 57.8% ± 6.2%, respectively; P < .0001). HRD-HSCT resulted in superior survival compared with chemotherapy alone (4-year DFS, 73.1% ± 7.1% vs 44.2% ± 6.2%, respectively; P < .0001; 4-year OS, 77.5% ± 7.1% vs 54.7% ± 6.3%, respectively; P = .001). Multivariate analysis revealed postremission treatment (HRD-HSCT vs chemotherapy) and high WBC counts at diagnosis as independent risk factors affecting relapse, DFS, and OS. Our results suggest that HRD-HSCT is superior to chemotherapy alone as postremission treatment for AML.

Cellular therapies in acute lymphoblastic leukemia

ALL remains a difficult disease to treat. In the adult setting, most patients will ultimately die of their disease, whereas in the pediatric setting, relapsed and refractory disease remains a therapeutic challenge. Cellular therapy through allo-HSCT remains an option for these patients, and recent advances in alternative forms of allo-HSCT, including unrelated donor transplants, UCB transplants, and haploidentical transplants, have expanded the numbers of patients eligible for allo-HSCT but have not improved outcomes when compared with HLA-matched related allo-HSCTs. In light of this persistent failure, several novel adoptive cellular approaches are being investigated to treat patients with ALL. The use of enriched WT-1–specific donor T cells to treat patients with ALL is currently under investigation in phase I trials at several centers. Treatment of ALL with genetically modified T cells targeted to the CD19 antigen through the expression of a CD19-specific CAR also have entered phase I clinical trials at several centers. Similarly, a clinical trial treating patients with ALL with genetically modified NK cells targeted to the CD19 antigen has recently opened for accrual. Collectively, these ongoing and anticipated trials provide a promising role for adoptive cellular therapies in the treatment of ALL. What remains to be seen is whether this promise will either translate into improved outcomes for these patients or provide significant insights on which to design second-generation adoptive cell therapeutic clinical trials for ALL in the future.

Unmanipulated HLA-mismatched/haploidentical peripheral blood stem cell transplantation for high-risk hematologic malignancies

BACKGROUND

Haploidentical hematopoietic stem cell transplantation (HSCT) has been increasingly applied in high-risk hematologic patients due to the absence of HLA-matched donors. The aim of this study was to investigate the efficacy and safety of unmanipulated haploidentical allogeneic peripheral blood stem cells transplantation (PBSCT) for hematologic malignancies.

STUDY DESIGN AND METHODS

Patients who underwent unmanipulated HLA-mismatched/haploidentical PBSCT from July 2007 to March 2010 with high-risk hematologic malignancies were enrolled for retrospective analysis.

RESULTS

Twenty-one patients with high-risk hematologic malignancies underwent unmanipulated HLA-mismatched/haploidentical PBSCT with myeloablative conditioning. The numbers of CD34+ cells infused at transplantation were 4.81 (range, 2.61-11.47)×10(6)/kg. Patients achieved myeloid and platelet engraftment at a median of 16.5 and 20 days, respectively. The cumulative incidence of acute graft-versus-host disease (GVHD) on Day 100 was 52.7±10.7%, and the 2-year cumulative incidence of chronic GVHD was 39.5±10.6%. The cumulative incidences of cytomegalovirus antigenemia and hemorrhagic cystitis within 100 days after PBSCT were 59.5±16.7 and 34.8±13.3%, respectively. One hundred-day transplantation-related mortality (TRM) rate and the 2-year cumulative TRM rate were 14.3 and 20.5±7.8%, respectively. The 2-year cumulative overall survival was 62.1±11.4% and the probability of disease-free survival at 2 years was 55.6±10.7% with a 16-month median follow-up.

CONCLUSION

Unmanipulated PBSCT is a promising protocol in HLA-mismatched/haploidentical transplant settings.