Haploidentical hematopoietic stem cell transplantation in adults with Philadelphia-negative acute lymphoblastic leukemia: no difference in the high- and low-risk groups

Allogeneic haematopoietic stem cell transplantation for adult T-lymphoblastic lymphoma: A real-world multicentre analysis in China

In this multicentre, real-world study, we aimed to identify the clinical outcomes and safety of allogeneic haematopoietic stem cell transplantation (allo-HSCT) in T-lymphoblastic lymphoma (T-LBL). A total of 130 Ann Arbor stage III or IV T-LBL patients (>16 years) treated with allo-HSCT across five transplant centres were enrolled. The 2-year cumulative incidence of disease progression, the probabilities of progression-free survival (PFS), overall survival (OS) and non-relapse mortality (NRM) after allo-HSCT were 21.0%, 69.8%, 79.5% and 9.2% respectively. Patients with central nervous system (CNS) involvement had a higher cumulative incidence of disease progression compared with those without CNS involvement (57.1% vs. 18.9%, HR 3.78, p = 0.014). Patients receiving allo-HSCT in non-remission (NR) had a poorer PFS compared with those receiving allo-HSCT in complete remission (CR) or partial remission (49.2% vs. 72.7%, HR 2.21, p = 0.041). Particularly for patients with bone marrow involvement and achieving CR before allo-HSCT, measurable residual disease (MRD) positivity before allo-HSCT was associated with a poorer PFS compared with MRD negativity (62.7% vs. 86.8%, HR 1.94, p = 0.036). On multivariate analysis, CNS involvement at diagnosis and receiving allo-HSCT in NR were associated with disease progression. Thus, our real-world data suggested that allo-HSCT appeared to be an effective therapy for adult T-LBL patients with Ann Arbor stage III or IV disease.

Mutation of the TP53 gene in acute lymphoblastic leukemia does not affect survival outcomes after haploidentical hematopoietic stem cell transplantation

Previous studies have demonstrated that TP53 mutation is correlated with insufficient therapy response and unfavorable prognosis in acute lymphoblastic leukemia (ALL). Few studies have investigated the impact of TP53 mutation in ALL patients after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We completed a retrospective study of 65 ALL patients with available TP53 status who underwent haplo-HSCT. They were divided into a TP53 mutation group (TP53^mut ) and a TP53 wild-type (TP53^wt ) group. TP53^mut showed comparable 2-year cumulative incidence of relapse (CIR) rates (13.1% vs 12.5%, P = .96) and 2-year leukemia-free survival (LFS) (74.2% vs 77.4%, P = .80) with TP53^wt . No significant differences in 2-year overall survival (OS) rates (82.9% vs 87.3%, P = .61) or 2-year NRM rates (12.7% vs 10.2%, P = .69) were observed in TP53^mut and TP53^wt patients. Multivariate analysis suggested that white blood cell (WBC) count at initial diagnosis (>50 × 10⁹ /L: hazard ratio [HR] = 3.860, P = .016) and age (>40 years old: HR = 4.120, P = .012) are independent risk factors for 2-year LFS. Our study showed that TP53 mutations may not be related to the unfavorable impact on survival in ALL patients after treatment with haplo-HSCT. The present results suggested that haplo-HSCT may eliminate the poor prognosis effect of TP53 mutation in ALL.

Haploidentical vs. sibling, unrelated, or cord blood hematopoietic cell transplantation for acute lymphoblastic leukemia

Haploidentical HCT is the preferred alternate donor approach for adults with ALL.

Haploidentical transplantation had similar survival compared with fully HLA-matched donor HCT but with reduced GVHD.

The role of haploidentical hematopoietic cell transplantation (HCT) using posttransplant cyclophosphamide (PTCy) for acute lymphoblastic leukemia (ALL) is being defined. We performed a retrospective, multivariable analysis comparing outcomes of HCT approaches by donor for adults with ALL in remission. The primary objective was to compare overall survival (OS) among haploidentical HCTs using PTCy and HLA-matched sibling donor (MSD), 8/8 HLA-matched unrelated donor (MUD), 7 /8 HLA-MUD, or umbilical cord blood (UCB) HCT. Comparing haploidentical HCT to MSD HCT, we found that OS, leukemia-free survival (LFS), nonrelapse mortality (NRM), relapse, and acute graft-versus-host disease (aGVHD) were not different but chronic GVHD (cGVHD) was higher in MSD HCT. Compared with MUD HCT, OS, LFS, and relapse were not different, but MUD HCT had increased NRM (hazard ratio [HR], 1.42; P = .02), grade 3 to 4 aGVHD (HR, 1.59; P = .005), and cGVHD. Compared with 7/8 UD HCT, LFS and relapse were not different, but 7/8 UD HCT had worse OS (HR, 1.38; P = .01) and increased NRM (HR, 2.13; P ≤ .001), grade 3 to 4 aGVHD (HR, 1.86; P = .003), and cGVHD (HR, 1.72; P ≤ .001). Compared with UCB HCT, late OS, late LFS, relapse, and cGVHD were not different but UCB HCT had worse early OS (≤18 months; HR, 1.93; P < .001), worse early LFS (HR, 1.40; P = .007) and increased incidences of NRM (HR, 2.08; P < .001) and grade 3 to 4 aGVHD (HR, 1.97; P < .001). Haploidentical HCT using PTCy showed no difference in survival but less GVHD compared with traditional MSD and MUD HCT and is the preferred alternative donor HCT option for adults with ALL in complete remission.

Integrating CAR T-Cell Therapy and Transplantation: Comparisons of Safety and Long-Term Efficacy of Allogeneic Hematopoietic Stem Cell Transplantation After CAR T-Cell or Chemotherapy-Based Complete Remission in B-Cell Acute Lymphoblastic Leukemia

Patients often undergo consolidation allogeneic hematopoietic stem cell transplantation (allo-HSCT) to maintain long-term remission following chimeric antigen receptor (CAR) T-cell therapy. Comparisons of safety and efficacy of allo-HSCT following complete remission (CR) achieved by CAR-T therapy versus by chemotherapy for B-cell acute lymphoblastic leukemia (B-ALL) has not been reported. We performed a parallel comparison of transplant outcomes in 105 consecutive B-ALL patients who received allo-HSCT after achieving CR with CAR-T therapy (n=27) or with chemotherapy (n=78). The CAR-T-allo-HSCT group had more patients in second CR compared to the chemotherapy-allo-HSCT group (78% vs. 37%; p<0.01) and more with complex cytogenetics (44% vs. 6%; p<0.001) but the proportion of patients with pre-transplant minimal residual disease (MRD) was similar. The median follow-up time was 49 months (range: 25-54 months). The CAR-T cohort had a higher incidence of Grade II-IV acute graft-versus-host disease (aGVHD 48.1% [95% CI: 46.1-50.1%] vs. 25.6% [95%CI: 25.2-26.0%]; p=0.016). The incidence of Grade III-IV aGVHD was similar in both groups (11.1% vs.11.5%, p=0.945). The overall incidence of chronic GVHD in the CAR-T group was higher compared to the chemotherapy group (73.3% [95%CI: 71.3-75.3%] vs. 55.0% [95%CI: 54.2-55.8%], p=0.107), but the rate of extensive chronic GVHD was similar (11.1% vs.11.9%, p=0.964). Efficacy measures 4 years following transplant were all similar in the CAR-T vs. the chemotherapy groups: cumulative incidences of relapse (CIR; 11.1% vs.12.8%; p=0.84), cumulative incidences of non-relapse mortality (NRM; 18.7% vs. 23.1%; p=0.641) leukemia-free survival (LFS; 70.2% vs. 64.1%; p=0.63) and overall survival (OS; 70.2% vs. 65.4%; p=0.681). We found that pre-transplant MRD-negative CR predicted a lower CIR and a higher LFS compared with MRD-positive CR. In conclusion, our data indicate that, in B-ALL patients, similar clinical safety outcomes could be achieved with either CD19 CAR T-cell therapy followed by allo-HSCT or chemotherapy followed by allo-HSCT. Despite the inclusion of more patients with advanced diseases in the CAR-T group, the 4-year LFS and OS achieved with CAR T-cells followed by allo-HSCT were as remarkable as those achieved with chemotherapy followed by allo-HSCT. Further confirmation of these results requires larger, randomized clinical trials.

Outcomes of Adolescents and Young Adults Compared with Children with Acute Leukemia after Single-Unit Unrelated Cord Blood Transplantation Using Myeloablative Conditioning without Antithymocyte Globulin

BACKGROUND

Although the use of cord blood transplantation (CBT) is becoming more frequent in acute leukemia, considering the relationship between the low stem cell dose and graft failure, whether use of CBT for adolescents and young adults (AYAs) is appropriate remains uncertain.

METHODS

A retrospective registry-based analysis of clinical outcomes and immune reconstitution was conducted for 105 AYAs and 187 children with acute leukemia who underwent single-unit CBT using myeloablative conditioning (MAC) without antithymocyte globulin (ATG).

RESULTS

Outcomes were similar between AYAs and children, except for nonrelapse mortality (NRM) and recovery rates of neutrophils and platelets. The 30-day cumulative incidence of neutrophil engraftment was similar between AYAs and children, but children had faster rates of neutrophil and platelet recovery than AYAs. The median time to neutrophil engraftment was earlier in children than in AYAs (AYAs, 19 days, 95% confidence interval [CI] 17.3-21.7; children, 16 days, 95% CI 13.1-19.5, p = 0.00003). The incidence of platelet recovery on day 120 was higher in children than in AYAs (AYAs, 80%, 95% CI 71-81%; children, 88%, 95% CI 82-92%, p = 0.037). CD34+ cell dose was the only independent factor influencing both neutrophil and platelet recovery. The cumulative incidence of NRM at 2 years was higher among AYAs than among children (AYAs, 27.5%, 95% CI 20-37%; children, 15%, 95% CI 10-21%, p = 0.008). Conditioning regimen was an independent factor influencing NRM. With respect to immune reconstitution, natural killer cell counts quickly recovered to normal levels 1-month post-CBT in both children and AYAs. CD8+ T-cell counts were higher in children than in AYAs at 1 and 3 months post-CBT. CD4+ T-cell counts were similar in both children and AYAs after CBT.

CONCLUSION

AYAs with acute leukemia have outcomes of single-unit CBT using MAC without ATG that are as good as those of children. Thus, single-unit CBT using modified MAC without ATG is an acceptable choice for both AYAs and children who do not have a suitable donor.

G-CSF-Primed Peripheral Blood Stem Cell Haploidentical Transplantation Could Achieve Satisfactory Clinical Outcomes for Acute Leukemia Patients in the First Complete Remission: A Registered Study

G-CSF-mobilized peripheral blood (G-PB) harvest is the predominant graft for identical sibling donor and unrelated donor allogeneic hematopoietic stem cell transplantation (HSCT) recipients, but it was controversial in haploidentical related donor (HID) HSCT. In this registry study, we aimed to identify the efficacy of HID G-PB HSCT (HID-PBSCT) for acute leukemia (AL) patients in first complete remission (CR1). Also, we reported the outcomes for the use of G-PB grafts in comparison with the combination of G-BM and G-PB grafts in HID HSCT recipients. Sixty-seven AL patients in CR1 who received HID-PBSCT were recruited at Institute of Hematology, Peking University. Patients who received haploidentical HSCT using the combination of G-BM and G-PB harvests in the same period were enrolled as controls (n=392). The median time from HSCT to neutrophil and platelet engraftment was 12 days (range, 9-19 days) and 12 days (range, 8-171 days), respectively. The 28-day cumulative incidence of neutrophil and platelet engraftment after HSCT was 98.5% and 95.5%, respectively. The cumulative incidences of grade II-IV and grade III-IV acute graft-versus-host disease (GVHD) were 29.9% (95%CI 18.8-40.9%) and 7.5% (95%CI 1.1-13.8%), respectively. The cumulative incidences of total and moderate-severe chronic GVHD were 54.9% (95%CI 40.9-68.8%) and 17.4% (95%CI 6.7-28.0%), respectively. The cumulative incidences of relapse and non-relapse mortality were 13.9% (95%CI 5.4-22.5%) and 3.4% (95%CI 0-8.1%), respectively. The probabilities of overall survival (OS) and leukemia-free survival (LFS) were 84.7% (95%CI 74.7-94.7%) and 82.7% (95%CI 73.3-92.1%) respectively. Compared with the HID HSCT recipients using the combination of G-BM and G-PB grafts, the engraftments of neutrophil and platelet were both significantly faster for the G-PB group, and the other clinical outcomes were all comparable between the groups. In multivariate analysis, graft types did not influence the clinical outcomes. Overall, for the patients with AL CR1, G-PB graft could be considered an acceptable graft for HID HSCT recipients. This study was registered at https://clinicaltrials.gov as NCT03756675.

Minimal residual disease monitoring and preemptive immunotherapies for frequent 11q23 rearranged acute leukemia after allogeneic hematopoietic stem cell transplantation

The prognosis of 11q23/KMT2A-rearranged (KMT2A-r) acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poor. Minimal residual disease (MRD) is an important prognostic factor for relapse. Thus, we aimed to identify the evolution of KMT2A before and after allo-HSCT and the efficacy of preemptive immunotherapies for KMT2A-r AL patients receiving allo-HSCT. KMT2A expression was determined through TaqMan-based RQ-PCR technology. Preemptive immunotherapies included interferon-α and donor lymphocyte infusion. We collected 1751 bone marrow samples from 177 consecutive KMT2A-r AL patients. Pre-HSCT KMT2A positivity was correlated with post-HSCT KMT2A positivity (correlation coefficient=0.371, P<0.001). The rates of achieving KMT2A negativity after allo-HSCT were 96.6%, 92.9%, and 68.8% in the pre-HSCT low-level group (>0, <0.1%), intermediate-level group (≥ 0.1%, <1%), and high-level group (≥1%), respectively. The rates of regaining KMT2A positivity after allo-HSCT were 7.7%, 35.7%, 38.5%, and 45.5% for the pre-HSCT KMT2A-negative, low-level, intermediate-level, and high-level groups, respectively (P<0.001). The 4-year cumulative incidence of relapse after allo-HSCT was as high as 53.7% in the pre-HSCT KMT2A expression ≥ 0.1% group, which was compared to the KMT2A-negative group (15.1%) and KMT2A <0.1% group (31.2%). The clinical outcomes of patients with post-HSCT KMT2A positivity were poorer than those of patients with persistent KMT2A negativity. Although post-HSCT preemptive immunotherapies might help to achieve KMT2A negativity, the long-term efficacy was unsatisfactory. Thus, pre-HSCT KMT2A positivity was significantly associated with post-HSCT KMT2A positivity. The clinical outcomes of patients with post-HSCT KMT2A positivity were poor, which might not be overcome by commonly used immunotherapies.

Unmanipulated haploidentical hematopoietic stem cell transplantation for children with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal disorders and is rare in children. Allogeneic hematopoietic stem cell transplantation (HSCT) is commonly used in children with MDS with excess blasts and in patients with refractory cytopenia of childhood (RCC) associated with monosomy 7, complex karyotype, severe neutropenia, or transfusion dependence. We recruited 27 children with MDS who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT). At transplantation, 10 patients had RCC, 12 patients had advanced MDS (RAEB and RAEB-T), and 5 patients had myelodysplasia-related acute myeloid leukemia (MDR-AML). All patients received granulocyte colony-stimulating factor (G-CSF)-mobilized bone marrow cells and peripheral blood stem cells. At a median follow-up of 24.1 months (range: 2.0-74.5 months) after HSCT, the estimated probabilities of 3-year disease-free survival (DFS) and overall survival (OS) were both 81.9% (95% CI, 66.8-100.0%). The estimated 3-year incidences of relapse (CIR) and non-relapse mortality (NRM) were both 7.4% (95% CI, 1.2%-21.4%). The 100-day cumulative incidence of grade II-IV aGVHD was 52.6% (95% CI, 42.9-62.3%), while that of grade III-IV aGVHD was 11.1% (95% CI, 5.1-17.1%). The 3-year cumulative incidences of overall and extensive cGVHD were 42.3% (95% CI, 19.8%-57.5%) and 21.1% (95% CI, 2.5%-63.2%), respectively. Univariate analysis showed that chronic GVHD significantly affected OS and DFS. Haploidentical HSCT may be an effective treatment option with easier donor availability for pediatric patients with MDS.

Monosomal karyotype is associated with poor outcomes in patients with Philadelphia chromosome-negative acute lymphoblastic leukemia receiving chemotherapy but not allogeneic hematopoietic stem cell transplantation

Monosomal karyotype (MK) is associated with poor prognosis in patients with myeloid neoplasms; however, its prognostic significance in Philadelphia chromosome-negative (Ph-negative) acute lymphoblastic leukemia (ALL) remains unclear. Data of 323 patients with Ph-negative ALL treated at Peking University People's Hospital were retrospectively analyzed. MK was identified in 49 (14.8%) patients. The patients with MK had lower hemoglobin levels (P = 0.026), lower platelet count (P = 0.032), higher percentages of blasts in the peripheral blood at diagnosis (P = 0.008), and higher percentages of high-risk karyotypes (P < 0.001) compared with those without MK. The complete remission (CR) rate and the minimal residual disease negativity rate were not significantly different between patients with and without MK. In the multivariate analysis, MK was identified as an independent factor associated with higher cumulative incidence of relapse (CIR) (hazard ratio (HR), 2.07; 95% confidence interval (CI), 1.02, 4.21; P = 0.043), shorter disease-free survival (DFS) (HR, 2.80; 95% CI, 1.20, 6.54; P = 0.017) and shorter overall survival (OS) (HR, 5.75; 95% CI, 2.07, 16.03; P = 0.001) in the chemotherapy cohort; however, MK had no impact on outcomes in the allogeneic hematopoietic stem cell transplantation (allo-HSCT) cohort. Mantel-Byar analysis showed that allo-HSCT was associated with lower CIR (P < 0.001), longer DFS (P < 0.001), and longer OS (P < 0.001) in CR patients with MK. In conclusion, our study showed that MK was an independent predictor of poor outcomes in patients with Ph-negative ALL receiving chemotherapy but not allo-HSCT, and allo-HSCT could improve the outcomes of patients with MK.

Unmanipulated haploidentical peripheral blood stem cell transplantation for patients with Philadelphia-negative acute lymphoblastic leukaemia in first complete remission

Haploidentical peripheral blood stem cell transplantation (Haplo-PBSCT) is a promising treatment option for patients with Ph-negative acute lymphoblastic leukemia (ALL). In this study, we retrospectively analyzed data from Ph-negative ALL patients who underwent haplo-PBSCT during their first complete remission (CR1), and compared the long-term outcomes between the standard-risk and high-risk patients. The 3-year probability of relapse was 7.6% and 16.7% for the standard- and high-risk group (p = .274). The 3-year probability of disease-free survival (DFS) and overall survival (OS) for the standard-risk versus high-risk groups were 84.6% versus 50% (p = .0063) and 92.3% versus 61.1% (p = .046), respectively. Univariate analysis showed that a diagnosis of high risk with fusion/mutation genes were associated with worse outcomes, which was confirmed by multivariate analysis (p = .016). In summary, haplo-PBSCT may be a promising alternative for patients with Ph-negative ALL in CR1, although the fusion/mutation genes in high-risk patients may relatively impair the long-term efficacy compared with standard-risk patients.

Hematopoietic Cell Transplantation in the Treatment of Adult Acute Lymphoblastic Leukemia: Updated 2019 Evidence-Based Review from the American Society for Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in adults with acute lymphoblastic leukemia (ALL) is reviewed and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the recommendations. A panel of ALL experts developed consensus on the treatment recommendations based on the evidence. Allogeneic HCT offers a survival benefit in selected patients with ALL, and this review summarizes the standard indications as well as the areas of controversy. There is now greater experience with pediatric-inspired chemotherapy regimens that has transformed upfront therapy for adult ALL, resulting in higher remission rates and overall survival. This in turn has increased the equipoise around decision making for ALL in first complete remission (CR1) when there is no measurable residual disease (MRD) at the end of induction and/or consolidation. Randomized studies are needed for adults with ALL to compare allogeneic HCT in CR1 with pediatric-inspired chemotherapy alone. Indications for transplantation in the evolving landscape of MRD assessments and novel targeted and immune therapeutics remain important areas of investigation.

Perspectives on the Use of a Medium-Dose Etoposide, Cyclophosphamide, and Total Body Irradiation Conditioning Regimen in Allogeneic Hematopoietic Stem Cell Transplantation: The Japanese Experience from 1993 to Present

The outcome for adults with acute lymphoblastic leukemia (ALL) treated with chemotherapy or autologous hematopoietic stem cell transplantation (HSCT) is poor. Therefore, allogeneic HSCT (allo HSCT) for adults aged less than 50 years with ALL is performed with myeloablative conditioning (MAC) regimens. Among the several MAC regimens, a conditioning regimen of 120 mg/kg (60mg/kg for two days) cyclophosphamide (CY) and 12 gray fractionated (12 gray in six fractions for three days) total body irradiation (TBI) is commonly used, resulting in a long term survival rate of approximately 50% when transplanted at the first complete remission. The addition of 30 mg/kg (15 mg/kg for two days) etoposide (ETP) to the CY/TBI regimen revealed an excellent outcome (a long-term survival rate of approximately 80%) in adults with ALL, showing lower relapse and non-relapse mortality rates. It is preferable to perform allo HSCT with a medium-dose ETP/CY/TBI conditioning regimen at the first complete remission in high-risk ALL patients and at the second complete remission (in addition to the first complete remission) in standard-risk ALL patients. The ETP dose and administration schedule are important factors for reducing the relapse and non-relapse mortality rates, preserving a better outcome. The pharmacological study suggests that the prolonged administration of ETP at a reduced dose is a promising treatment.

Comparable Outcomes after Hematopoietic Stem Cell Transplantation from Mother Donors and Matched Unrelated Donors in Patients with Hematopoietic Malignancies

Haploidentical transplantations have achieved comparable survival as HLA fully matched unrelated donors (URDs). When choosing the best donor for HLA haploidentical transplantations, most institutions prioritize using young male donors over mother donors. In a retrospective study we compared outcomes in mother donor and URD transplantations. We found that both 2-year overall survival and 2-year leukemia-free survival were comparable between the mother donor group and URD group (74.8% versus 72.9%, P = .937, and 71.7% versus 67.0%, P = .580, respectively). Higher incidences of grades II to IV acute graft-versus-host disease (GVHD) and chronic GVHD were observed in the mother donor group than in the URD group (43.5% versus 14.0%, P = .001, and 62.2% versus 38.7%, P = .007, respectively). The 2-year cumulative incidences of relapse were significantly decreased in the mother donor group (7.6% versus 20.9%, P = .036). These findings suggest mother donor transplantations could achieve comparable survival with URD transplantations and exhibited decreased rates of relapse but increased rates of GVHD, indicating that mother donors would be a suitable choice for patients without an identical sibling donor.

Chemotherapy plus DLI for relapse after haploidentical HSCT: the biological characteristics of relapse influences clinical outcomes of acute leukemia patients

This study investigated the prognostic factors in patients (n = 89) who experienced relapse and received chemotherapy plus donor leukocyte infusion (Chemo-DLI) after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Patients with early relapse (< 6 vs. > 6 months after haplo-HSCT), higher bone marrow blast count before chemo-DLI (> 20% vs. 5-19%), and without chronic graft-versus-host disease (cGVHD) after chemo-DLI had a higher rate of progressive disease (PD) and worse progression-free survival (PFS) and overall survival (OS). In multivariate analysis, non-cGVHD after Chemo-DLI and high blast count predicted a higher risk of PD and poorer PFS, and non-cGVHD after Chemo-DLI and early relapse predicted poorer OS. The patients were stratified into three groups according to these three risk factors. Patients with all three risk factors (n = 14) had the highest PD rate and poorest survival compared with those with one or two risk factors (n = 63) or no risk factors (n = 12). Thus, early relapse, high leukemia burden before Chemo-DLI, and non-cGVHD after Chemo-DLI can predict outcomes in patients who have experienced relapse and received Chemo-DLI after haplo-HSCT. New therapeutic strategies should be identified for these patients.

The role of collateral related donors in haploidentical hematopoietic stem cell transplantation

A key issue in the haploiedntical hematopoietic stem cell transplantation (haplo-HSCT) setting is the search for the best donor, because donor selection can significantly impact the clinical outcomes. We aimed to identify the role of collateral related donors (CRDs) in donor selection for haplo-HSCT through comparing the clinical outcomes between CRDs (n = 60) and maternal donors (MDs, n = 296), which were the last choice of donor selection in immediate related donors (IRDs). The cumulative incidence of graft-versus-host disease was comparable between CRDs and MDs. The 5-year cumulative incidence of relapse and non-relapse mortality was 22.0% (95% CI, 11.3%-32.7%) versus 17.4% (95% CI, 13.0%-21.8%) (P = 0.455) and 25.0% (95% CI, 13.9%-36.1%) versus 23.1% (95% CI, 18.2%-28.0%) (P = 0.721) for the CRDs and MDs, respectively. The 5-year probabilities of disease-free survival and overall survival was 53.2% (95% CI, 40.4%-66.0%) versus 59.5% (95% CI, 53.8%-65.2%) (P = 0.406) and 56.5% (95% CI, 43.8%-69.2%) versus 61.8% (95% CI, 56.1%-67.5%) (P = 0.458) for the CRDs and MDs, respectively. Female donor/male recipient (FDMR) CRDs were associated with the poorest clinical outcomes, and the clinical outcomes of non-FDMR CRDs were comparable to those of MDs. In summary, our results showed that CRDs did not showed superiority over MDs. Thus, IRDs should be the first choice of donor selection, and CRDs could only be the donors for those without IRDs.

Is human leukocyte antigen-matched sibling donor transplant always better than haploidentical allograft?

Currently, haploidentical donor has been an alternative source of stem cell allografts for patients who have no human leukocyte antigen-matched sibling donor or unrelated donors. A number of studies indicated that treating hematological malignancy patients with haploidentical stem cell transplantation (haplo-SCT) could achieve comparable outcomes to those who underwent matched sibling donor transplantation (MSDT). In recent years, more and more evidence support the notion that haploidentical allografts may have a stronger graft-vs-leukemia (GVL) effect than MSDT. In this review, we summarized the transplant outcomes of haplo-SCT and MSDT, mainly focusing on the subgroup of patients who will benefit from the stronger GVL effects of haplo-SCT compared with MSDT. We also offered strategies of how to translate the strong antileukemia activity of haploidentical allograft into superior survival. Future directions of GVL effects in haplo-SCT settings were also discussed.

CD20 expression sub-stratifies standard-risk patients with B cell precursor acute lymphoblastic leukemia

Patients with standard-risk adult acute lymphoblastic leukemia (ALL) treated with chemotherapy do not have satisfactory outcomes. To more precisely classify ALL patients and optimize treatment, we re-evaluated the risk stratification system by examining CD20 expression and other classic risk factors at diagnosis. We retrospectively analyzed response to induction chemotherapy of 217 consecutive patients with newly diagnosed Philadelphia-negative B cell precursor-ALL. Survival analyses were conducted for the 136 patients who were intended to be treated with chemotherapy alone. Among the 217 patients, 69 (31.8%) were considered standard risk based on age <35 years, white blood cell count <30 × 10⁹/L, absence of central nervous system involvement, and high-risk cytogenetic abnormalities. Seventy-four patients (34.1%) expressed CD20 on ≥20% of leukemia blasts and were considered CD20 positive. We found that fewer CD20-positive than CD20-negative patients achieved durable first complete responses (CR1 ≥3 months) (81.1% vs. 94.9%, P=0.002). Within the standard-risk group, more CD20-negative than CD20-positive patients achieved CR (100% vs. 83.3%, P=0.003) and durable CR1 (100% vs. 82.4%, P=0.014). For patients in the CD20-negative standard-risk, CD20-positive standard-risk, CD20-negative high-risk, and CD20-positive high-risk groups, the 3-year cumulative incidence of relapse was 42.6%, 70.0%, 59.3%, and 69.5%, respectively (P=0.118); the 3-year disease-free survival rates were 52.1%, 0%, 20.7%, and 13.7%, respectively (P=0.006); and the 3-year overall survival rates were 55.8%, 13.8%, 23.6%, and 16.9%, respectively (P=0.006). Our results suggest that patients with CD20-negative standard-risk B cell precursor-ALL have favorable prognosis compared with CD20-positive standard-risk or CD20-negative or -positive high-risk patients. CD20-positive standard-risk ALL patients may need other therapeutic modalities bridging to allogeneic hematopoietic stem cell transplantation.

Haploidentical transplantation compared with matched sibling and unrelated donor transplantation for adults with standard-risk acute lymphoblastic leukaemia in first complete remission

We retrospectively investigated outcomes of haploidentical donor (HID) transplant for adults with standard-risk acute lymphoblastic leukaemia (ALL) in first complete remission (CR1) compared with human leucocyte antigen (HLA)-matched sibling donor (MSD) and HLA-matched unrelated donor (MUD) transplants. A total of 348 adult patients were enrolled, including 127 HID, 144 MSD and 77 MUD recipients. The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 39·5%, 24·0% and 40·3% for HID, MSD and MUD, respectively (P = 0·020). However, there was no difference in grade III-IV aGVHD (11·4%, 7·7%, 13·5%, respectively, P = 0·468). The 5-year cumulative transplant-related mortality was 16·4%, 11·6% and 19·6% (P = 0·162), the 5-year relapse rate post-transplantation was 14·8%, 21·1% and 16·7% (P = 0·231), the 5-year overall survival was 70·1%, 73·7% and 69·8% (P = 0·525), and the 5-year disease-free survival was 68·7%, 67·3% and 63·7%, respectively (P = 0·606). Furthermore, the 3-year GVHD-free, relapse-free survival was not different (50·8%, 54·9% and 52·2%, respectively, P = 0·847). Our results indicate that the outcomes of HID transplants are equivalent to those of MSD and MUD, and that HID transplantation is a valid alternative for standard-risk adults with ALL in CR1 who lack matched donors.

Haploidentical hematopoietic stem cell transplantation for pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia in the imatinib era

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains an important curative option for children with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) who have a poor response to chemotherapy plus imatinib. For such children, if there are no matched related or unrelated donors, alternative donor transplantation may be a choice. The role of haploidentical donor (HID) HSCT in pediatric patients with Ph+ ALL has not been reported. The study population included pediatric patients with Ph+ ALL who underwent HID-HSCT. BCR-ABL transcript levels were analyzed using real-time quantitative reverse transcription polymerase chain reaction. At a median follow-up of 34 months, the 5-year probabilities of event-free survival (EFS) and overall survival (OS) were 61.0% and 70.0%, respectively in HID HSCT. The 3-year incidence of relapse and non-relapse mortality was 22.7% and 16.4%. Multivariate analysis showed that the post-HSCT BCR-ABL transcript level on +30day was a significant factor affecting relapse rate. HID HSCT for the treatment of pediatric patients with Ph+ ALL yielded promising long-term survival. Post-HSCT BCR-ABL transcript positivity was a significant factor for clinical relapse after allo-HSCT in the imatinib era.

The impact of minimal residual disease prior to unmanipulated haploidentical hematopoietic stem cell transplantation in patients with acute myeloid leukemia in complete remission

The minimal residual disease (MRD) before and after a haploidentical hematopoietic stem cell transplantation (HSCT) of 86 patients with acute myeloid leukemia (AML) in complete remission (CR) was measured using flow cytometry (FCM) and Wilms tumor 1 (WT1). In all, 18 patients met the criteria of pre-MRD + before HSCT. The FCM + (p = .028) and the combinative criteria for positive MRD (MRDco+) (p = .022) post-transplantation were significantly correlated to relapse in univariate analysis. A multivariate analysis showed that only MRDco + post-transplantation was an independent risk factor of leukemia relapse (p = .022, HR = 4.653, 95% CI: 1.249-17.334). A significant difference in the cumulative incidence of relapse between patients with or without post-transplant MRDco + was observed (p < .001). However, the results suggested that the MRD status before transplantation might not affect leukemia relapse of patients with AML in CR after haploidentical HSCT. These types of patients might not need to receive further intensive chemotherapy or active intervention concerning HSCT.

[Comparison of immune reconstitution at early stage after unmanipulated haploidentical stem cell transplantation between high- and standard- risk Philadelphia chromosome- negative acute lymphoblastic leukemia patients in CR1]

目的

比较费城染色体（Ph）阴性急性淋巴细胞白血病（ALL）第1次完全缓解期（CR1）高危组与标危组患者非体外去T细胞单倍型骨髓联合外周血造血干细胞移植（haploidentical blood and marrow stem cell transplatation, HBMT）术后早期免疫重建与预后特征。

方法

以2010年1月至2012年12月在北京大学人民医院行HBMT的49例Ph阴性ALL CR1患者为研究对象，应用流式细胞术分别检测患者＋30 d、+60 d及＋90 d外周血CD19⁺、CD3⁺、CD4⁺、CD8⁺、CD4⁺CD45RO⁺、CD4⁺CD45RA⁺、CD4⁺CD28⁺及CD8⁺CD28⁺淋巴细胞亚群免疫重建指标，比较标危组（18例）、成人高危组（16例）及儿童高危组（15例）淋巴细胞亚群早期重建规律、生存状况及预后。

结果

三组患者CD3⁺、CD4⁺CD28⁺、CD8⁺CD28⁺、CD4⁺CD45RO⁺和CD4⁺CD45RA⁺等早期免疫重建（+30 d、+60 d及＋90 d）指标差异均无统计学意义。标危组、成人高危组及儿童高危组患者2年复发率（27.8%、31.3%、26.7%，P=0.957）、2年非复发死亡率（11.1%、0、13.3%，P=0.185）、2年无白血病生存率（61.1%、68.8%、60.0%，P=0.834）及总生存率（77.8%、68.8%、60.0%，P=0.529）差异均无统计学意义。三组患者移植后100 d内Ⅱ~Ⅳ度急性移植物抗宿主病发生率（44.4%、12.5%、46.7%，P=0.075）和2年总慢性移植物抗宿主病发生率（61.1%、50.0%、40.0%，P=0.249）差异无统计学意义。

结论

在HBMT模式下，Ph阴性ALL CR1高危组与标危组患者移植后可取得相当的早期免疫重建，这可能是克服移植前高危因素并取得相同移植疗效的免疫机制之一。

Comparison of outcomes after umbilical cord blood and unmanipulated haploidentical hematopoietic stem cell transplantation in children with high-risk acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective therapy for children with high-risk acute lymphoblastic leukemia (ALL). Human leukocyte antigen (HLA)-haploidentical HSCT (haplo-HSCT) or umbilical cord blood transplantation (UCBT) are both important alternative sources of stem cells for those without an HLA-identical sibling donor or unrelated matched donor. We aimed to compare the therapeutic effects of single UCBT and unmanipulated haplo-HSCT in high-risk ALL children (n = 129). Hematopoietic recovery was significantly faster in haplo-HSCT recipients than in UCBT recipients. The 2-year cumulative incidences of relapse in the haplo-HSCT and UCBT groups were 16.1% and 24.1%, respectively (p = 0.169). The 2-year cumulative incidences of non-relapse mortality in the haplo-HSCT and UCBT groups were 12.8% and 18.8%, respectively (p = 0.277). The 2-year probabilities of overall survival in the haplo-HSCT and UCBT groups were 82.0% and 69.6%, respectively (p = 0.071), and the 2-year probability of disease-free survival in the haplo-HSCT group was higher than in the UCBT group (71.0% vs. 57.2%, p = 0.040). However, several variables (such as leukocyte count and cytogenetics at diagnosis) were different between the groups, and a possible center effect should also be considered. In addition, only mild and moderate chronic graft-versus-host disease (GVHD) was associated with significantly improved survival compared to those without chronic GVHD in multivariate analysis. Thus, our results show that both unmanipulated haplo-HSCT and UCBT are valid for high-risk ALL children lacking a HLA matched donor, and both strategies expand the donor pool for children in need.

How do we choose the best donor for T-cell-replete, HLA-haploidentical transplantation?

In haploidentical stem cell transplantations (haplo-SCT), nearly all patients have more than one donor. A key issue in the haplo-SCT setting is the search for the best donor, because donor selection can significantly impact the incidences of acute and chronic graft-versus-host disease, transplant-related mortality, and relapse, in addition to overall survival. In this review, we focused on factors associated with transplant outcomes following unmanipulated haplo-SCT with anti-thymocyte globulin (ATG) or after T-cell-replete haplo-SCT with post-transplantation cyclophosphamide (PT/Cy). We summarized the effects of the primary factors, including donor-specific antibodies against human leukocyte antigens (HLA); donor age and gender; killer immunoglobulin-like receptor-ligand mismatches; and non-inherited maternal antigen mismatches. We also offered some expert recommendations and proposed an algorithm for selecting donors for unmanipulated haplo-SCT with ATG and for T-cell-replete haplo-SCT with PT/Cy.

Granulocyte colony-stimulating factor-primed bone marrow: an excellent stem-cell source for transplantation in acute myelocytic leukemia and chronic myelocytic leukemia

Background:

Steady-state bone marrow (SS-BM) and granulocyte colony-stimulating growth factor-primed BM/peripheral blood stem-cell (G-BM/G-PBSC) are the main stem-cell sources used in allogeneic hematopoietic stem-cell transplantation. Here, we evaluated the treatment effects of SS-BM and G-BM/G-PBSC in human leucocyte antigen (HLA)-identical sibling transplantation.

Methods:

A total of 226 patients (acute myelogenous leukemia-complete remission 1, chronic myelogenous leukemia-chronic phase 1) received SS-BM, G-BM, or G-PBSC from an HLA-identical sibling. Clinical outcomes (graft-versus-host disease [GVHD], overall survival, transplant-related mortality [TRM], and leukemia-free survival [LFS]) were analyzed.

Results:

When compared to SS-BM, G-BM gave faster recovery time to neutrophil or platelet (P < 0.05). Incidence of grade III-IV acute GVHD and extensive chronic GVHD (cGVHD) was lower than seen with SS-BM (P < 0.05) and similar to G-PBSC. Although the incidence of cGVHD in the G-BM group was similar to SS-BM, both were lower than G-PBSC (P < 0.05). G-BM and G-PBSC exhibited similar survival, LFS, and TRM, but were significantly different from SS-BM (P < 0.05). There were no significant differences in leukemia relapse rates among the groups (P > 0.05).

Conclusions:

G-CSF-primed bone marrow shared the advantages of G-PBSC and SS-BM. We conclude that G-BM is an excellent stem-cell source that may be preferable to G-PBSC or SS-BM in patients receiving HLA-identical sibling hematopoietic stem-cell transplantation.

Modern approaches to HLA-haploidentical blood or marrow transplantation

Allogeneic blood or bone-marrow transplantation (alloBMT) is a potentially curative treatment for a variety of haematological malignancies and nonmalignant diseases. Historically, human leukocyte antigen (HLA)-matched siblings have been the preferred source of donor cells owing to superior outcomes compared with alloBMT using other donors. Although only approximately one-third of patients have an HLA-matched sibling, nearly all patients have HLA-haploidentical related donors. Early studies using HLA-haploidentical alloBMT resulted in unacceptably high rates of graft rejection and graft-versus-host disease (GVHD), leading to high nonrelapse mortality and consequently poor survival. Several novel approaches to HLA-haploidentical alloBMT have yielded encouraging results with high rates of successful engraftment, effective GVHD control and favourable outcomes. In fact, outcomes of several retrospective comparative studies seem similar to those seen using other allograft sources, including those of HLA-matched-sibling alloBMT. In this Review, we provide an overview of the three most-developed approaches to HLA-haploidentical alloBMT: T-cell depletion with 'megadose' CD34(+) cells; granulocyte colony-stimulating factor-primed allografts combined with intensive pharmacological immunosuppression, including antithymocyte globulin; and high-dose, post-transplantation cyclophosphamide. We review the preclinical and biological data supporting each approach, results from major clinical studies, and completed or ongoing clinical studies comparing these approaches with other alloBMT platforms.

Favorable outcome of haploidentical hematopoietic stem cell transplantation in Philadelphia chromosome-positive acute lymphoblastic leukemia: a multicenter study in Southwest China

Background

Since the introduction of tyrosine kinase inhibitors (TKIs) into combination chemotherapy regimens, the majority of newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) patients have achieved complete remission (CR). However, without allogeneic hematopoietic stem cell transplantation (HSCT), long-term outcomes in adults remain unsatisfactory. Indeed, haploidentical HSCT has become a common treatment for adult patients who lack an HLA-matched donor, though limited data are available on the efficacy of haploidentical HSCT in Ph+ ALL patients.

Methods

We analyzed the clinical outcomes of 82 Ph+ ALL patients who underwent haploidentical HSCT (n = 47) or HLA-matched HSCT (n = 35). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to assess BCR-ABL expression. All of the patients were treated with an imatinib-based regimen before undergoing HSCT. Imatinib treatment was resumed in the patients’ posttransplantation following detection of BCR-ABL transcripts.

Results

All of the patients achieved neutrophil and platelet engraftment, with the exception of five patients who died prior to engraftment. Haploidentical HSCT was associated with higher incidences of acute graft-versus-host disease (GVHD) (51.1 vs. 25.7 %, p < 0.05) and chronic GVHD (48.9 vs. 25.7 %, p < 0.05) compared with HLA-matched HSCT, but there was no difference in the incidence of either grades III–IV acute GVHD or extensive chronic GVHD. The incidence of cytomegalovirus (CMV) infection was significantly higher in the patients treated with haploidentical HSCT than in those treated with HLA-matched HSCT (38.3 vs. 14.3 %, p < 0.05). Haploidentical HSCT was associated with a significantly lower relapse rate compared with HLA-matched HSCT (44.8 vs. 19.1 %, p < 0.05). There were no differences in non-relapse mortality (NRM), leukemia-free survival (LFS), or overall survival (OS) between the patients who received HLA-matched HSCT and those who underwent haploidentical HSCT.

Conclusions

Our data indicate that the incidence of NRM after HSCT is similar between the patients who receive HLA-matched donor cells and those who receive haploidentical donor cells and that haploidentical HSCT reduces the relapse rate. Haploidentical HSCT represents an encouraging treatment option for Ph+ ALL patients who lack a suitable HLA-matched donor.

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.

Haploidentical hematopoietic stem cell transplantation without in vitro T cell depletion for the treatment of philadelphia chromosome-positive acute lymphoblastic leukemia

The role of haploidentical related allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) is not clear. We aimed to investigate the long-term survival of Ph(+) ALL patients who underwent haploidentical donor (HID)-HSCT and to analyze the factors influencing relapse and survival after allo-HSCT. The study population included Ph(+) ALL patients who underwent haploidentical related allo-HSCT. Additionally, Ph(+) ALL patients who underwent HLA-matched related donor (MRD) transplants during the same period were included to compare outcomes. BCR-ABL transcript levels were analyzed by using real-time quantitative reverse transcription PCR. Clinical data from 139 Ph(+) ALL patients who received allo-HSCT in our center were analyzed. Of these patients, 101 received HID transplants and 38 received MRD transplants. At a median follow-up of 36 months, 5-year disease-free survival (DFS) and overall survival (OS) rates in the HID transplant group were 65.8% and 74.0%, respectively. The 5-year cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) rates for the HID transplant group were 20.3% and 15.6%, respectively. In addition, there were no differences in OS, DFS, CIR, and NRM between the HID and MRD groups. Multivariate analysis showed that imatinib resistance was a significant factor influencing DFS and CIR in HID transplant patients. Haploidentical HSCT for the treatment of Ph(+) ALL achieves promising long-term survival, which is comparable with that of HLA-MRD HSCT. Imatinib resistance is a negative predictor of relapse and DFS after allo-HSCT.