Autologous hematopoietic stem cell transplantation in adult acute lymphoblastic leukemia: still not out of fashion

Fate of hematopoietic stem cells determined by Notch1 signaling (Review)

Regulation of the fate of hematopoietic stem cells (HSCs), including silencing, self-renewal or differentiation into blood line cells, is crucial to maintain the homeostasis of the human blood system and prevent leukemia. Notch1, a key receptor in the Notch signaling pathway, plays an important regulatory role in these properties of HSCs, particularly in the maintenance of the stemness of HSCs. In recent decades, the ubiquitination modification of Notch1 has been gradually revealed, and also demonstrated to affect the proliferation and differentiation of HSCs. Therefore, a detailed elucidation of Notch1 and its ubiquitination modification may help to improve understanding of the maintenance of HSC properties and the pathogenesis of leukemia. In addition, it may aid in identifying potential therapeutic targets for specific leukemias and provide potential prognostic indicators for HSC transplantation (HSCT). In the present review, the association between Notch1 and HSCs and the link between the ubiquitination modification of Notch1 and HSCs were described. In addition, the association between abnormal HSCs mediated by Notch1 or ubiquitinated Notch1and T-cell acute lymphoblastic leukemia (T-ALL) was also examined, which provides a promising direction for clinical application.

How I Use Measurable Residual Disease in the Clinical Management of Adult Acute Lymphoblastic Leukemia

Over the last decade the use of measurable residual disease (MRD) diagnostics in adult acute lymphoblastic leukemia (ALL) has expanded from a limited number of study groups in Europe and the United States to a world-wide application. In this review, we summarize the advantages and drawbacks of the current available techniques used for MRD monitoring. Through the use of three representative case studies, we highlight the advances in the use of MRD in clinical decision-making in the management of ALL in adults. We acknowledge discrepancies in MRD monitoring and treatment between different countries, reflecting differing availability, accessibility and affordability.

Optimizing autologous hematopoietic stem cell transplantation for acute leukemia

Autologous hematopoietic stem cell transplantation (ASCT) remains an important postremission treatment for acute leukemia (AL). It is known that some prognostic factors, such as age, cytogenetic and molecular risk stratification, and minimal residual disease (MRD) status, are closely related to clinical outcomes following ASCT. Moreover, there are multiple measurements, including pretransplant treatment, stem cell mobilization and collection, conditioning regimens, and maintenance treatment after transplantation, that can affect prognosis after ASCT. Our clinical practice of ASCT should be better standardized to further improve patient outcomes. This review outlines optimization and quality control measures for ASCT developed at the Institute of Hematology and Blood Diseases Hospital of the Chinese Academy of Medical Sciences, the first established and largest autologous stem cell transplant center in China. These measures will enhance the development of best practices and strategies for AL ASCT therapies, thereby improving patient outcomes.

Outcomes of Adults with Acute Lymphoblastic Leukemia After Autologous Hematopoietic Stem Cell Transplantation and the Significance of Pretransplantation Minimal Residual Disease: Analysis from a Single Center of China

Background:

The postremission therapies for adult patients generally contain consolidation chemotherapy, allogeneic hematopoietic stem cell transplantation and autologous hematopoietic stem cell transplantation (auto-HSCT). Because of the various results from different centers, the optimal therapy for adult acute lymphoblastic leukemia (ALL) patients is still uncertain. This study aimed to better understand predictive factors and role of auto-HSCT in the postremission therapy for adult ALL patients.

Methods:

The outcomes of 135 adult patients with ALL, who received the first auto-HSCT in Hematopoietic Stem Cell Transplantation Center of Blood Diseases Hospital, Chinese Academy of Medical Sciences from January 1, 1994 to February 28, 2014, were retrospectively analyzed. Survival curves were estimated using the Kaplan-Meier method and simultaneous effects of multiple covariates were estimated with the Cox model.

Results:

Overall survival (OS) and disease-free survival (DFS) at 5 years for the whole cohort were 59.1 ± 4.5% and 59.0 ± 4.4%, respectively. The cumulative nonrelapse mortality and relapse rate at 5 years were 4.5 ± 0.03% and 36.6 ± 0.19%. For both OS and DFS, acute T-cell lymphoblastic leukemia, high lactate dehydrogenase (LDH) at diagnosis, blast cell proportion ≥5% on the 15^th day of induction therapy, and extramedullary infiltration before HSCT were the poor prognosis factors. In addition, age ≥35 years predicted poor DFS. Only T-ALL and high LDH were the independent undesirable factors associated with OS and DFS in Cox regression model. For 44 patients who had results of pretransplantation minimal residual disease (MRD), positive MRD (MRD ≥0.01%) indicated poor OS (P = 0.044) and DFS (P = 0.008). Furthermore, for the standard risk group, the patients with negative MRD (MRD <0.01%) had better results (OS at 18 months was 90.0 ± 9.5%, while for the patients with positive MRD OS was 50.0 ± 35.4%, P = 0.003; DFS at 18 months was 90.0 ± 9.5%, while for the positive MRD group DFS was 0%, P < 0.001).

Conclusions:

This study confirmed that auto-HSCT combined with posttransplantation maintenance chemotherapy could be an option for adult ALL patients and pretransplantation MRD may play a significant role in the direction of therapy for adult ALL patients.

[Outcomes of adults with Ph-negative B-cell acute lymphoblastic leukemia after autologous hematopoietic stem cell transplantation and the significance of minimal residual disease]

目的

探讨自体造血干细胞移植（auto-HSCT）在成人Ph染色体阴性急性B淋巴细胞白血病（B-ALL）中的地位及其预后因素。

方法

回顾性分析1996年1月至2014年2月86例首次行auto-HSCT患者的疗效。

结果

5年总生存（OS）和无病生存（DFS）率分别为（63.8±5.6）％和（60.9±5.6）%，5年累积无复发死亡（NRM）率和复发率分别为（4.70±0.05）％和（34.40±0.31）%。年龄≥35岁、诊断时乳酸脱氢酶水平高、高白细胞起病、首次诱导治疗第15天骨髓原始细胞比例≥5%、第1次完全缓解（CR1）至移植时间间隔>6个月及回输物中CD34⁺细胞数≥3.8×10⁶/kg均为不良预后因素。且CR1至移植时间间隔>6个月是影响预后的独立不良因素。34例患者具有微小残留病（MRD）检测结果，显示移植前MRD阳性（MRD≥0.01 %）、首次诱导化疗后MRD未转阴或巩固化疗过程中MRD转阳均提示不良预后，且巩固化疗中MRD转阳是影响DFS的独立不良因素。

结论

auto-HSCT联合维持化疗是成人B-ALL治疗的可选方案。由于移植前及化疗过程中MRD阴性结果提示更好的结局，故MRD可能在指导成人B-ALL移植治疗中具有重要意义。