Improving results of autologous stem cell transplantation for Philadelphia-positive acute lymphoblastic leukaemia in the era of tyrosine kinase inhibitors: a report from the Acute Leukaemia Working Party of the European Group for Blood and Marrow Transplantation

Outcomes of allogeneic or autologous stem cell transplantation followed by maintenance chemotherapy in adult patient with B-ALL in CR1 with no detectable minimal residual disease

Autologous haematopoietic stem cell transplantation (auto-HSCT) as a treatment for B-cell acute lymphoblastic leukaemia (B-ALL) has been rigorously debated in recent years. We retrospectively analysed the outcomes of 355 adult patients with B-ALL in first complete remission who had received auto-HSCT or allogeneic HSCT (allo-HSCT) in our centre. The treatment efficacy was evaluated from a model stratified on the risk classification and minimal residue disease (MRD) status after three chemotherapy cycles. Auto-HSCT demonstrated comparable 3-year overall survival (OS) (72.7% vs. 68.5%, p = 0.441) and leukaemia-free survival rates (62.8% vs. 56.1%, p = 0.383) compared to allo-HSCT for patients with negative MRD, while the advantage of lower non-relapse mortality (1.5% vs. 25.1%, p < 0.001) was offset by a higher cumulative incidence of relapse (CIR) rates (35.7% vs. 18.9%, p = 0.018), especially in high-risk patients. For patients at high risk and with positive MRD, there was a lower trend of 3-year OS (50.0% vs. 66.0%, p = 0.078) and significantly higher CIR rates (71.4% vs. 39.1%, p = 0.018) in auto-HSCT. However, no significant interaction was observed in the tests. In conclusion, auto-HSCT appears to be an attractive treatment for patients with negative MRD after three chemotherapy cycles. For MRD-positive patients, allo-HSCT may be a more effective treatment.

Autologous versus allogeneic hematopoietic cell transplantation for older patients with acute lymphoblastic leukemia. An analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) with reduced intensity conditioning (RIC) is an option for elderly patients with acute lymphoblastic leukemia (ALL). We retrospectively compared results of RIC-allo-HCT from either a matched sibling donor (MSD, n = 209) or matched unrelated donor (MUD, n = 209) with autologous (auto, n = 142) HCT for patients aged 55 years or more treated in first complete remission (CR1) between 2000 and 2018. The probabilities of leukemia-free survival (LFS) at 5 years were 34% for RIC-allo-HCT versus 39% for auto-HCT (p = 0.11) while overall survival (OS) rates were 42% versus 45% (p = 0.23), respectively. The incidence of relapse (RI) and non-relapse mortality (NRM) was 41% versus 51% (p = 0.22) and 25% versus 10% (p = 0.001), respectively. In a multivariate model, using auto-HCT as reference, the risk of NRM was increased for MSD-HCT (Hazard ratio [HR] = 2.1, p = 0.02) and MUD-HCT (HR = 3.08, p < 0.001), which for MUD-HCT translated into a decreased chance of LFS (HR = 1.55, p = 0.01) and OS (HR = 1.62, p = 0.008). No significant associations were found with respect to the risk of relapse. We conclude that for patients with ALL in CR1, aged above 55 years, auto-HCT may be considered a transplant option alternative to RIC-allo-HCT, although its value requires verification in prospective trials.

Treatment of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia in Adults

Simple Summary

Outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) dramatically improved during the past 20 years with the advent of tyrosine kinase inhibitors and monoclonal antibodies. Their great efficacy in young and fit patients led to question our reliance on chemotherapy and allogeneic hematopoietic stem cell transplantation. Moreover, these well-tolerated treatments can be safely administrated even in the elderly that represent the majority of Ph+ ALL patient. This review will focus on the recent changes of paradigm in the management of Ph+ ALL patients and the development of novel therapeutic strategies.

Abstract

Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) is the most common subtype of B-ALL in adults and its incidence increases with age. It is characterized by the presence of BCR-ABL oncoprotein that plays a central role in the leukemogenesis of Ph+ ALL. Ph+ ALL patients traditionally had dismal prognosis and long-term survivors were only observed among patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first complete remission (CR1). However, feasibility of allo-HSCT is limited in this elderly population. Fortunately, development of increasingly powerful tyrosine kinase inhibitors (TKIs) from the beginning of the 2000′s dramatically improved the prognosis of Ph+ ALL patients with complete response rates above 90%, deep molecular responses and prolonged survival, altogether with good tolerance. TKIs became the keystone of Ph+ ALL management and their great efficacy led to develop reduced-intensity chemotherapy backbones. Subsequent introduction of blinatumomab allowed going further with development of chemo free strategies. This review will focus on these amazing recent advances as well as novel therapeutic strategies in adult Ph+ ALL.

The impact of tyrosine kinase inhibitors on allogeneic hematopoietic stem cell transplantation for adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

In the tyrosine kinase inhibitor (TKI) era, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still the most potential approach for cure of adult patients with Philadelphia chromosome-positive acute lymphocytic leukemia (Ph⁺ ALL). TKI plus chemotherapy has strikingly increased response rates and depth of response, and facilitated allo-HSCT, which decreases relapse and improves survival eventually. Meanwhile, for those with older age or comorbidities at diagnosis, TKI in combination with reduced-intensity chemotherapy or chemotherapy-free strategy reduces treatment-related mortality, deferred intensive chemotherapy increases molecular responses and reduced-intensity conditioning (RIC) allo-HSCT improves survival finally. Of note, according to minimal residual disease (MRD) and BCR/ABL1 kinase domain mutation screening, prophylactic or preemptive maintenance therapy with a sensitive TKI decreases relapse further. Regarding transplantation-related mortality and impaired quality of life related to complications of allo-HSCT, autologous-HSCT (auto-HSCT) among those with early and persistent molecular remission and the most potent TKI ponatinib plus intensive chemotherapy has exhibited non-inferior survival to allo-HSCT. Even so, risk-adapted strategy isn't available now. Lastly, outcomes of relapse after allo-HSCT are dismal due to TKIs exposure, and new therapeutic interventions combined with TKIs shed light on this thorny problem.

Comparison of autologous and allogeneic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

Objectives: To analyze the outcomes of patients who received autologous stem cell transplantation (auto-SCT), matched sibling donor stem cell transplantation (MSD-SCT) and haploidentical stem cell transplantation (haplo-SCT) and provide the basis for the choice of transplantation method in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Methods: We retrospectively investigated the outcomes of 119 adult patients with Ph+ ALL in our center. The overall survival (OS) rate, leukemia-free survival (LFS) rate, cumulative incidence of relapse (CIR) rate, non-relapse mortality (NRM) rate and the impact of achievement of complete molecular response (CMR) within 3 months and sustaining CMR up to transplantation (s3CMR) on transplantation method were explored. Results: The estimated OS, LFS, CIR and NRM rates at 3 years were not significantly different among three groups (p = 0.960, 0.917, 0.375 and 0.096, respectively). For the 65 patients who achieved s3CMR, there was no significant difference in OS (84.5% vs 72.5% vs 100%, p = 0.374), LFS (75.2% vs 64.5% vs 83.3%, p = 0.668), CIR (17.2% vs 8.1% vs 16.7%, p = 0.583) and NRM (3.1% vs 23.4% vs 0%, p = 0.055) among auto-SCT group, MSD-SCT group and haplo-SCT group. However, in patients who did not achieve s3CMR, auto-SCT recipients tended to have higher CIR (60% vs 33.2% vs 24.0%, p = 0.013) than the allo-HSCT group. Conclusions: Auto-SCT with maintenance therapy after HSCT appears to be an attractive treatment option for patients with Ph+ ALL especially for those whose s3CMR was kept up to transplantation. For non-s3CMR patients, allogeneic transplantation may be more effective from lower relapse.

Case Report: A Case With Philadelphia Chromosome Positive T-Cell Lymphoblastic Lymphoma and a Review of Literature

Philadelphia chromosome positive (Ph⁺) in T-lineage acute lymphoproliferative tumors is a rare event in both children and adults. In particular, it has not been reported in T-cell lymphoblastic lymphoma(T-LBL) yet. Here, we describe a patient with Ph⁺ T-LBL for both cytogenetic abnormality and BCR-ABL1 fusion transcript. Moreover, we review the published cases of Ph⁺ T-cell acute lymphoblastic leukemia (T-ALL) in the literature and summarize their clinical characteristics, management, and prognosis.

Comparative study on allogeneic with autologous hematopoietic stem cell transplantation in adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia in the era of TKIs: a systematic review and meta-analysis

In the era of tyrosine kinase inhibitors (TKIs), allogeneic hematopoietic stem cell transplantation (allo-HSCT) is recommended as a standard approach for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) achieving complete remission (CR). However, the role of autologous hematopoietic stem cell transplantation (auto-HSCT) in adult patients achieving complete molecular remission (CMR) is an alternative, less toxic treatment options, especially for the patients who lack suitable donors and are unfit for allo-HSCT. Thus, we conducted a systematic review and meta-analysis to compare the efficacy of allo-HSCT and auto-HSCT for the treatment of adult patients with Ph+ ALL. We searched the PubMed, Embase, Scopus, and Cochrane Library for studies published before June 2019 without language restriction. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for overall survival (OS) and relapse-free survival (RFS) and odds ratios (ORs) and 95% CIs for relapse rate (RR) and treatment-related mortality (TRM). Four prospective studies and one retrospective study were included with a total of 810 patients. We found auto-HSCT was superior to allo-HSCT in OS (HR = 1.42, 95% CI: 1.06-1.91, P = 0.02), and there was no difference between allo-HSCT and auto-HSCT for RFS (HR = 1.10, 95% CI: 0.86-1.40, P = 0.44) and RR (OR = 0.53, 95% CI: 0.22-1.26, P = 0.15). The risk of TRM for patients undergoing allo-HSCT was significantly higher than that of the patients who received auto-HSCT (OR = 5.06, 95% CI: 1.03-24.75, P = 0.05). Our meta-analysis shows that auto-HSCT may be an attractive and alternative treatment option for adult Ph+ ALL patients achieving CMR, with similar or better outcomes than allo-HSCT in the era of TKIs.

[Comparison of autologous versus matched sibling donor stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia]

目的

比较自体造血干细胞移植（auto-HSCT）和同胞全相合造血干细胞移植（MSD-HSCT）治疗费城染色体阳性急性淋巴细胞白血病（Ph⁺ ALL）的疗效，为患者移植方式的选择提供依据。

方法

回顾性总结2008年1月至2017年12月于中国医学科学院血液病医院行auto-HSCT（31例）及MSD-HSCT（47例）的78例Ph⁺ ALL患者的临床特征，比较不同移植方式患者的总生存（OS）率、无白血病生存（LFS）率、累积复发率（CIR）及非复发死亡率（NRM），并观察是否3个月内实现完全分子学缓解并持续至移植（s3CMR）条件下不同移植方式对预后的影响。

结果

auto-HSCT组、MSD-HSCT组粒细胞植入的中位时间分别为12（10～29）d、14（11～24）d（P＝0.006），血小板植入的中位时间分别为17.5（10～62）d、17（10～33）d（P＝0.794）。MSD-HSCT组中，Ⅱ～Ⅳ度和Ⅲ～Ⅳ度急性移植物抗宿主病（GVHD）的发生率分别为27.7%（13/47）和8.5%（4/47），局限型和广泛型慢性GVHD的发生率为17.0%（8/47）和12.8%（6/47）。auto-HSCT组、MSD-HSCT组3年CIR、NRM、LFS率差异均无统计学意义（P值均>0.05）。在达到s3CMR的44例患者中，auto-HSCT组和MSD-HSCT组的3年OS率［（84.0±8.6）%对（78.0±8.7）%，P＝0.612］、LFS率［（70.3±10.3）%对（68.2±10.1）%，P＝0.970］、CIR［（24.9±10.0）%对（14.4±8.0）%，P＝0.286］和NRM［（4.7±4.7）%对（17.4±8.1）%，P＝0.209］差异均无统计学意义；未达到s3CMR的34例患者中，auto-HSCT组与MSD-HSCT组相比，3年CIR明显升高［（80.0±14.7）%对（39.6±10.9）%，P＝0.057］。

结论

对于化疗后达s3CMR的Ph⁺ ALL患者，auto-HSCT是一种有效的巩固治疗选择，与MSD-HSCT疗效相当；对于未达到s3CMR的患者，MSD-HSCT复发率更低。

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.

Treatment Selection for Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia in the Era of Tyrosine Kinase Inhibitors

With the advent of tyrosine kinase inhibitors (TKIs), the treatment of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) has entered a new era. The efficacy of TKIs compared with other ALL treatment options is emphasized by a rapid increase in the number of TKI clinical trials. Subsequently, the use of traditional approaches, such as combined chemotherapy and even allogeneic hematopoietic stem cell transplantation (allo-HSCT), for the treatment of ALL is being challenged in the clinic. In light of the increased use of TKIs in the clinic, several questions have been raised. First, is it necessary to use intensive chemotherapy during the induction course of therapy to achieve a minimal residual disease (MRD)-negative status? Must a patient reach a complete molecular response/major molecular response before receiving allo-HSCT? Does MRD status affect long-term survival after allo-HSCT? Is auto-HSCT an appropriate alternative for allo-HSCT in those Ph+ ALL patients who lack suitable donors? Here, we review the recent literature in an attempt to summarize the current status of TKI usage in the clinic, including several new therapeutic approaches, provide answers for the above questions, and speculate on the future direction of TKI utilization for the treatment of Ph+ ALL patients.

Trends in the use of hematopoietic stem cell transplantation for adults with acute lymphoblastic leukemia in Europe: a report from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Hematopoietic stem cell transplantation (HSCT) is considered an effective way to prevent relapse in adults with acute lymphoblastic leukemia (ALL). This study aimed to assess general trends in the use of various types of HSCTs performed between 2001 and 2015 in Europe, based on data reported to the European Society for Blood and Marrow Transplantation registry. We also evaluated HSCT rates with respect to ALL incidence in selected countries. Altogether, 15,346 first allogeneic (n = 13,460) or autologous (n = 1886) HSCTs were performed in the study period. Comparing 2013–2015 and 2001–2003, the number of allogeneic HSCTs performed in first complete remission increased by 136%, most prominently for transplantations from unrelated (272%) and mismatched related donors (339%). The number of HSCTs from matched sibling donors increased by 42%, while the total number of autologous HSCTs decreased by 70%. Increased use of allogeneic HSCT was stronger for Philadelphia chromosome (Ph)-positive (166%) than for Ph-negative ALL (38%) and for patients aged > 55 years (599%) than for younger adults (59%). The proportion of allogeneic HSCT with reduced-intensity conditioning (RIC) increased from 6 to 27%. The age-standardized rates of allogeneic HSCT per ALL incidence varied strongly among countries. Our analysis showed a continued trend toward increased allogeneic HSCT use for adults with ALL, which may be attributed to increasing availability of unrelated donors, wider use of RIC regimens, and improving efficacy of pretransplant therapy, including tyrosine kinase inhibitors for Ph-positive ALL. Allogeneic HSCT remains a major tool in the fight against ALL in adults.

[The prognostic significance of minimal residual disease detection after first induction treatment in adult acute lymphoblastic leukemia patients treated with autologous stem cell transplantation]

Objective: To investigate the prognostic significance of detection of minimal residual disease after first induction treatment (MRD(1)) in adult acute lymphoblastic leukemia (ALL) patients treated with autologous stem cell transplantation (auto-HSCT). Methods: The clinical data of 87 ALL patients who underwent auto-HSCT during February 2006 to April 2017 with MRD(1) detection data by flow cytometry were analyzed retrospectively. The relationship between MRD(1) and relapse and survival of ALL patients after auto-HSCT was studied. Results: Of 87 patients, 26 (29.9%) were MRD(1) positive. The proportion of high-risk immunophenotype (pro-B, pro-T, pre-T, mature T) was significantly higher in MRD(1)-positive patients than that in MRD(1) negative patients (34.6% vs 14.5%, P=0.038). There was no significant difference between positive and negative MRD(1) patients at age, sex, lineage (T/B), immunophenotype (standard risk/high risk), high white blood cell count (B-ALL>30×10(9)/L or T-ALL>100×10(9)/L), high-risk chromosome/gene ratio, the time from first complete remission to transplantation and pre-treatment regimen. The 5-year overall survival (OS) and leukemia-free survival (LFS) in MRD(1) negative and positive patients were 72.7% vs 47.3% (P=0.004) and 75.7% vs 29.6% (P<0.001), respectively. Multivariate analysis showed that positive MRD(1) was an independent risk factor for OS (HR=3.007, 95% CI 1.256-7.200, P=0.013) , and positive MRD(1) and high-risk immunophenotype were risk factors for LFS (HR=3.986, 95% CI 1.813-8.764, P=0.001; HR=2.981, 95% CI 1.373-6.473, P=0.006) . Conclusions: Auto-HSCT could not reverse the poor prognosis of MRD(1) positive patients. Auto-HSCT treatment is optional for patients with MRD(1) negative and maintaining MRD(1) negative status during intensive therapy.

The role of stem cell transplantation in the management of Philadelphia chromosome-positive acute lymphoblastic leukemia

The concurrent administration of tyrosine kinase inhibitors (TKIs) with standard chemotherapy together with allogeneic hematopoietic stem cell transplantation (alloHSCT) has improved the outcome of patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). Although to date, no study has shown alloHSCT to be inferior to chemotherapy plus TKIs in any subgroup of adult Ph+ ALL, there is some evidence suggesting no additional benefit of alloHSCT in patients with deep molecular responses to intensive chemotherapy with a second-generation, and especially, third-generation TKI. As none of these positive and negative studies are controlled, randomized trials are needed to fully define the role of alloHSCT in Ph+ ALL, especially in those with deep molecular response. However, if studies combining TKIs with new approaches such as immunotherapy lead to durable responses, alloHSCT in the first complete remission could be avoided in the near future in the majority of patients with Ph+ ALL.

Recent advances in the biology and treatment of B-cell acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a hematologic malignancy arising from precursors of the lymphoid lineage. Conventional cytotoxic chemotherapies have resulted in high cure rates of up to 90% in pediatric ALL, but the outcomes for adult patients remain suboptimal with 5-year survival rates of only 30%-40%. Over the last decade, major advances have been made in our understanding and management of ALL. Identification of new prognostic genomic markers and incorporation of minimal residual diseases' assessment into therapeutic protocols have improved risk stratification and treatment strategies. The use of pediatric-inspired regimens for adolescent and young adults, and the advent of tyrosine kinase inhibitors and novel targeted therapies, including monoclonal antibodies and chimeric antigen receptor T cells, have redefined the therapeutic paradigm of ALL, and significantly improved the outcomes. In this article, we will provide an overview of the current knowledge regarding the biology and treatment of ALL, and highlight recent diagnostic and therapeutic advances made in this area over the past 5 years.

Comparable results of autologous and allogeneic haematopoietic stem cell transplantation for adults with Philadelphia-positive acute lymphoblastic leukaemia in first complete molecular remission: An analysis by the Acute Leukemia Working Party of the EBMT

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (alloHSCT) is considered a standard treatment for patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL) achieving complete remission after induction containing tyrosine kinase inhibitors (TKIs).

METHODS

We retrospectively compared results of myeloablative alloHSCT from either matched sibling donor (MSD) or unrelated donor (URD) with autologous (auto) HSCT for adults with Ph+ ALL in molecular remission, treated between 2007 and 2014.

RESULTS

In univariate analysis, the incidence of relapse at 2 years was 47% after autoHSCT, 28% after MSD-HSCT and 19% after URD-HSCT (P = 0.0002). Respective rates of non-relapse mortality were 2%, 18%, and 22% (P = 0.001). The probabilities of leukaemia-free survival were 52%, 55% and 60% (P = 0.69), while overall survival rates were 70%, 70% and 69% (P = 0.58), respectively. In multivariate analysis, there was a trend towards increased risk of overall mortality after MSD-HSCT (hazard ratio [HR], 1.5, P = 0.12) and URD-HSCT (HR, 1.6, P = 0.08) when referred to autoHSCT. The use of total body irradiation (TBI)-based regimens was associated with reduced risk of relapse (HR, 0.65, P = 0.02) and overall mortality (HR, 0.67, P = 0.01).

CONCLUSION

In the era of TKIs, outcomes of myeloablative autoHSCT and alloHSCT for patients with Ph+ ALL in first molecular remission are comparable. Therefore, autoHSCT appears to be an attractive treatment option potentially allowing for circumvention of alloHSCT sequelae. Irrespective of the type of donor, TBI-based regimens should be considered the preferable type of conditioning for Ph+ ALL.

"Society of Hematologic Oncology (SOHO) State of the Art Updates and Next Questions"-Treatment of ALL

The outcome of adult acute lymphoblastic leukemia (ALL) has substantially improved by adopting pediatric-inspired regimens, and approximately half of the patients are nowadays cured. The evaluation of minimal residual disease currently represents the most important prognostic indicator, which drives treatment algorithms, which include allogeneic stem cell transplantation (allo-SCT) allocation. Indeed, for high-risk patients, allo-SCT should be pursued as soon as possible, whereas in standard-risk patients this procedure should be avoided also in light of related toxicity and because there are no significant benefits. Furthermore, better characterization of the molecular genetic events can drive therapeutic decisions: a historical example in this respect is represented by the use of tyrosine kinase inhibitors (TKIs) in Philadelphia chromosome-positive ALL; in the upcoming future, TKIs might be used also in other subgroups, such as breakpoint cluster region/Abelson 1-like cases and others with deregulated tyrosine kinases. Finally, the greatest progress is currently achieved with new immunotherapies targeting frequently expressed surface antigens in ALL. It is also a new chance for elderly ALL patients, so far spared from intensive chemotherapy and allo-SCT. These targeted therapies will substantially change this treatment algorithm and the great challenge is to find optimal sequence of the extended therapy options in an individual patient.

Hematopoietic stem cell transplant in adults with acute lymphoblastic leukemia: the present state

INTRODUCTION

Allogeneic hematopoietic stem cell transplant (allo-HSCT) has an important role in management of acute lymphoblastic leukemia (ALL). Proper patient selection is central to ensure optimal outcomes. Areas covered: This review covers various aspects of HSCT in ALL patients, including indications, donor selection, conditioning regimens, and post-transplant management. Expert commentary: Allo-HSCT is important in post-remission management of ALL but proper risk-stratification is a major challenge. Incorporation of minimal residual disease (MRD) and molecular testing will improve patient allocation. Patients receiving pediatric-inspired induction who achieve molecular remission might not need allo-HSCT in first remission. Allo-HSCT should be considered in patients who don't achieve MDR negativity, didn't receive intensive induction, or have high risk cytogenetic and molecular features. Despite improved responses with tyrosine kinase inhibitors (TKIs) in Philadelphia positive (Ph+) ALL, allo-HSCT remains standard. Matched sibling donors are the optimal graft source, but other sources are valid alternatives. There is no single optimal conditioning regimen and retrospective studies found myeloablative and reduced intensity regimens to be comparable. Following allo-HSCT, there is no role for maintenance therapy in Philadelphia-negative ALL. In Ph+ ALL, maintenance TKIs improve outcomes. The integration of targeted and immunotherapies in the peri-transplant period holds potential for improved outcomes.

Current paradigms in the management of Philadelphia chromosome positive acute lymphoblastic leukemia in adults

Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) is a biologically, clinically, and genetically distinct subtype of precursor-B ALL. The Ph chromosome, results from a reciprocal translocation of the ABL1 kinase gene on chromosome 9 to the breakpoint cluster region (BCR) gene on chromosome 22. Depending on the translocation breakpoint, typically a p210 BCR-ABL1 or a p190 BCR-ABL onc protein are generated; both are constitutively active tyrosine kinases that play a central role to alter signaling pathways of cell proliferation, survival, and self-renewal, leading to leukemogenesis. In Ph-positive ALL, the p190-BCR-ABL (minor [m]-bcr) subtype is more frequent than the p210-BCR-ABL (major [M]-bcr) subtype, commonly found in chronic myeloid leukemia. The Philadelphia chromosome is the most frequent recurrent cytogenetic abnormality in elderly patients with ALL. Its incidence increases with age, reaching ∼50% in patients with ALL aged 60 years and over. Patients traditionally had a very poor outcome with chemotherapy, particularly if they do not undergo allogeneic hematopoietic cell transplantation (allo-HCT) in first complete remission (CR1). With the availability of multiple tyrosine kinase inhibitors (TKI), the therapeutic armamentarium is expanding quickly. However, there is no consensus on how to best treat Ph-positive ALL. With modern therapy, improved outcomes have led to the emergence of a number of controversies, including the need for intensive chemotherapy, the ideal TKI, and whether all eligible patients should receive an allo-HSCT, and if so, what type. Here, we discuss these controversies in light of the available literature.

Diagnostic and treatment of adult Philadelphia chromosome-positive acute lymphoblastic leukemia

The outcome of adult patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) has improved substantially with the introduction of tyrosine kinase inhibitors (TKIs). TKIs are now integral components of therapy for Ph+ ALL. The current consensus is that they improve patient outcomes compared with historical control patients treated with chemotherapy alone, and increase the number of patients able to receive stem cell transplant. New challenges have emerged with respect to induction of resistance mainly via Abelson tyrosine kinase mutations. Several novel kinase inhibitors with significantly more potent antileukemic activity are currently being developed. Furthermore novel immune therapies, which recruit or modify patient's own T cells to fight leukemic cells, are being developed and could find an important place in Ph+ ALL therapy by few years. In this article, we reviewed treatment approaches in adults with Ph+ ALL with a focus on TKIs and combined chemotherapy regimens.

The development of agents targeting the BCR-ABL tyrosine kinase as Philadelphia chromosome-positive acute lymphoblastic leukemia treatment

INTRODUCTION

In Philadelphia chromosome-positive (Ph⁺) acute lymphoblastic leukemia (ALL), the BCR-ABL translocation is the main transforming event; consequently, it is targeted by ABL-tyrosine kinase inhibitors (TKIs), the first of which to be identified was imatinib mesylate. There are now four newer TKIs, three so-called second-generation inhibitors and one third generation inhibitor, all of which are more potent than imatinib in in vitro assays. Areas covered: This paper reviews the current knowledge on the function of BCR-ABL. Furthermore, this paper highlights the impact of this knowledge on the development of a targeted therapy approach in Ph⁺ ALL and the obstacles for the successful treatment with these drugs. Expert opinion: Identifying key components involved in disease pathogenesis may lead to new approaches that might overcome resistance mediated to the BCR-ABL TKIs. In a near future, the authors believe that monoclonal antibodies and immunotherapy should also be combined with TKIs and up-front chemotherapy for the successful treatment of ALL.

A sequential approach with imatinib, chemotherapy and transplant for adult Ph+ acute lymphoblastic leukemia: final results of the GIMEMA LAL 0904 study

In the GIMEMA LAL 0904 protocol, adult Philadelphia positive acute lymphoblastic leukemia patients were treated with chemotherapy for induction and consolidation, followed by maintenance with imatinib. The protocol was subsequently amended and imatinib was incorporated in the induction and post-remission phase together with chemotherapy. Due to the toxicity of this combined approach, the protocol was further amended to a sequential scheme based on imatinib plus steroids as induction, followed by consolidation with chemotherapy plus imatinib and, when applicable, by a hematopoietic stem cell transplant. Fifty-one patients (median age 45.9 years) were enrolled in the final sequential protocol. At the end of induction (day +50), 96% of evaluable patients (n=49) achieved a complete hematologic remission; after consolidation, all were in complete hematologic remission. No deaths in induction were recorded. Overall survival and disease-free survival at 60 months are 48.8% and 45.8%, respectively. At day +50 (end of imatinib induction), a more than 1.3 log-reduction of BCR-ABL1 levels was associated with a significantly longer disease-free survival (55.6%, 95%CI: 39.0-79.3 vs. 20%, 95%CI: 5.8-69.1; P=0.03), overall survival (59.1%, 95%CI: 42.3-82.6 vs. 20%, 95%CI: 5.8-69.1; P=0.02) and lower incidence of relapse (20.5%, 95%CI: 7.2-38.6 vs. 60.0%, 95%CI: 21.6-84.3; P=0.01). Mean BCR-ABL1 levels remained significantly higher in patients who subsequently relapsed. Finally, BCR-ABL1^p190 patients showed a significantly faster molecular response than BCR-ABL1^p210 patients (P=0.023). Though the study was not powered to evaluate the role of allogeneic stem cell transplant, allografting positively impacted on both overall and disease-free survival. In conclusion, a sequential approach with imatinib alone in induction, consolidated by chemotherapy plus imatinib followed by a stem cell transplant is a feasible, well-tolerated and effective strategy for adult Philadelphia positive acute lymphoblastic leukemia, leading to the best long-term survival rates so far reported. (clinicaltrials.gov identifier: 00458848).

Refining the Role of Hematopoietic Cell Transplantation for Acute Lymphoblastic Leukemia as Novel Therapies Emerge

Acute lymphoblastic leukemia (ALL) is a rare adult neoplasm. The disorder consists of precursor B or T phenotypes. In the pediatric population, ALL was a success story in that 80% of children with ALL enjoy long-term survival. In adults, similar complete remission rates are achieved with current induction regimens; however, less than 50% of patients are alive at 5 years, with most deaths due to relapsed disease. Accordingly, optimizing post remission consolidation therapy might improve in outcomes. Such strategies may include chemotherapy and autologous or allogeneic transplant. Moreover, the ability to modify such therapy based on better disease risk stratification while taking into account patient characteristics such as performance status and presence of comorbidities is necessary to tailor treatment accordingly. Here, we review available medical literature on the use of hematopoietic cell transplantation as a consolidation modality in the treatment of adult ALL.

Use of tyrosine kinase inhibitors to prevent relapse after allogeneic hematopoietic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: A position statement of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a standard of care for patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). The introduction of tyrosine kinase inhibitors (TKIs) to first-line therapy has improved overall outcomes; however, a significant proportion of patients still relapse after alloHSCT. Posttransplant TKI maintenance was demonstrated to reduce the risk of relapse in a large retrospective study and, therefore, should be considered a valuable option. This consensus paper, written on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, presents an overview of clinical studies on the use of TKIs after alloHSCT and proposes practical recommendations regarding the choice of TKI, treatment timing, and dosage. It is hoped that these recommendations will become the state of art in this field and, more importantly, lead to a reduction of Ph-positive ALL relapse after alloHSCT. Cancer 2016;122:2941-2951. © 2016 American Cancer Society.

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.

Autologous stem cell transplantation versus alternative allogeneic donor transplants in adult acute leukemias

The availability of alternative sources of stem cells including most recently T-replete haploidentical marrow or peripheral blood, and the increasing use of reduced-intensity conditioning (RIC), renders feasible an allogeneic transplant to almost all patients with acute leukemia up to 70 years of age. Autologous stem cell transplantation (ASCT) for consolidation of complete remission (CR), however, offers in some circumstances an alternative option. Although associated with a higher relapse rate, autologous transplant benefits from a lower non-relapse mortality, the absence of graft-versus-host disease (GVHD), and a better quality of life for long-term survivors. The recent use of intravenous busulfan (IVBU) with high-dose melphalan, better monitoring of minimal residual disease (MRD), and maintenance therapy post autografting bring new interest. Few retrospective studies compared the outcome following alternative donor versus autologous transplants for remission consolidation. Genoidentical and phenoidentical allogeneic stem cell transplantations are undisputed gold standards, but there are no data showing the superiority of alternative allogeneic donor over autologous transplantation, at the time of undetectable MRD, in patients with good- and intermediate-1 risk acute myelocytic leukemia (AML) in first complete remission (CR1), acute promyelocytic leukemia in second complete remission (CR2), and Philadelphia chromosome-positive (Ph(+)) acute lymphocytic leukemia (ALL).

Management of adult Ph-positive acute lymphoblastic leukemia

Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) has been regarded for decades as the ALL subgroup with the worse outcome. It represents the most frequent genetic subtype of adult ALL, and increases progressively with age. The introduction of tyrosine kinase inhibitors (TKIs) has enabled to obtain complete hematologic remissions (CHRs) in virtually all patients, including the elderly, to improve disease-free survival and overall survival, as well as to increase the percentage of patients who can undergo an allogeneic stem cell transplant (allo-SCT).

The current management of adult Ph+ ALL patients relies on the use of a TKI with or without chemotherapy followed by an allo-SCT, which still remains the only curative option. Minimal residual disease screening is permitting not only a better stratification of patients, but has also allowed to reconsider the role of autologous stem cell transplant for a set of patients who do not have a donor or are not eligible for an allo-SCT. At present, clinical challenges are represented by the emergence of resistant mutations, particularly the gatekeeper T315I, for which alternative approaches, comprising novel TKIs or therapies based on the combination of TKI with immunotherapeutic strategies, are being considered in order to overcome resistance.

Autologous stem cell transplantation for adult acute leukemia in 2015: time to rethink? Present status and future prospects

The use of autologous stem cell transplantation (ASCT) as consolidation therapy for adult patients with acute leukemia has declined over time. However, multiple randomized studies in the past have reported lower relapse rates after autologous transplantation compared with chemotherapy and lower non-relapse mortality rates compared with allogeneic transplantation. In addition, quality of life of long-term survivors is better after autologous transplantation than after allogeneic transplantation. Further, recent developments may improve outcomes of autograft recipients. These include the use of IV busulfan and the busulfan+melphalan combination, better detection of minimal residual disease (MRD) with molecular biology techniques, the introduction of targeted therapies and post-transplant maintenance therapy. Therefore, ASCT may nowadays be reconsidered for consolidation in the following patients if and when they reach a MRD-negative status: good- and at least intermediate-1 risk acute myelocytic leukemia in first CR, acute promyelocytic leukemia in second CR, Ph-positive acute lymphocytic leukemia. Conversely, patients with MRD-positive status or high-risk leukemia should not be considered for consolidation with ASCT.

High frequency and poor prognosis of late childhood BCR-ABL-positive and MLL-AF4-positive ALL define the need for advanced molecular diagnostics and improved therapeutic strategies in pediatric B-ALL in Pakistan

BACKGROUND

Fusion oncogenes (FOs) resulting from chromosomal abnormalities have an important role in leukemogenesis in pediatric B cell acute lymphoblastic leukemia (ALL). The most common FOs are BCR-ABL, MLL-AF4, ETV6-RUNX1, and TCF3-PBX1, all of which have important prognostic and drug selection implications. Moreover, frequencies of FOs have ethnic variations. We studied Pakistani frequencies of FOs, clinical pattern, and outcome in pediatric B-ALL.

METHODS

FOs were studied in 188 patients at diagnosis using reverse transcriptase-polymerase chain reaction (RT-PCR) and interphase fluorescent in situ hybridization (FISH). Data were analyzed using SPSS version 17 (SPSS Inc., Chicago, IL, USA).

RESULTS

FOs were detected in 87.2 % of patients. Mean overall survival was 70.9 weeks, 3-year survival was 31.9 %, and 3-year relapse-free survival was 18.1 %. Four patients died of drug toxicities. ETV6-RUNX1 (19.14 %) had better survival (110.9 weeks; p = 0.03); TCF3-PBX1 (2.1 %) was associated with inferior outcome and higher central nervous system (CNS) relapse risk; MLL-AF4 (18.1 %) was more common in the 8- to 15-year age group (24/34; p = 0.001) and was associated with organomegaly, low platelet count, and poor survival; and BCR-ABL (47.9 %) was associated with older age (7-15 years, 52/90), lower remission rates, shorter survival (43.73 ± 4.24 weeks) and higher white blood cell count. Overall, MLL-AF4 and BCR-ABL were detected in 66 % of B-ALL, presented in later childhood, and were associated with poor prognosis and inferior survival.

CONCLUSIONS

This study reports the highest ethnic frequency of BCR-ABL FO in pediatric ALL, and is consistent with previous reports from our region. Poor prognosis BCR-ABL and MLL-AF4 was detected in two-thirds of pediatric B-ALL and is likely to be the reason for the already reported poor survival of childhood ALL in South-East Asia. Furthermore, MLL-AF4, usually most common in infants, presented in later childhood in most of the ALL patients, which was one of the unique findings in our study. The results presented here highlight the need for mandatory inclusion of molecular testing for pediatric ALL patients in clinical decision making, together with the incorporation of tyrosine kinase inhibitors, as well as hematopoietic stem cell transplantation facilities, to improve treatment outcome for patients in developing countries.

Indications for allo- and auto-SCT for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2015

This is the sixth special report that the European Society for Blood and Marrow Transplantation regularly publishes on the current practice and indications for haematopoietic SCT for haematological diseases, solid tumours and immune disorders in Europe. Major changes have occurred in the field of haematopoietic SCT over the last years. Cord blood units as well as haploidentical donors have been increasingly used as stem cell sources for allo-SCT, thus, augmenting the possibility of finding a suitable donor for a patient. Continuous refinement of conditioning strategies has also expanded not only the number of potential indications but also has permitted consideration of older patients or those with co-morbidity for a transplant. There is accumulating evidence of the role of haematopoietic SCT in non-haematological disorders such as autoimmune diseases. On the other hand, the advent of new drugs and very effective targeted therapy has challenged the role of SCT in some instances or at least, modified its position in the treatment armamentarium of a given patient. An updated report with revised tables and operating definitions is presented.

[Comparison of outcomes of adult acute lymphoblastic leukemia patients underwent autologous and allogeneic hematopoietic stem cell transplantation]

OBJECTIVE

To compare the outcomes of adult patients with acute lymphoblastic leukemia (ALL) who underwent autologous hematopoietic stem cell transplantation (auto-HSCT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

From Jan 2007 to Dec 2010, 106 adult ALL patients were retrospectively divided into two groups, 50 in auto-HSCT group and 56 in allo-HSCT group. Auto-HSCT group included 21 patients with high-risk, 46 patients in CR1 and 4 cases in CR2. All the 50 patients had negative minimal residual disease (MRD) prior to HSCT. Allo-HSCT group included 44 patients with high risk, 51 patients in CR1 and 5 cases in CR2, 15 patients with positive MRD before allo-HSCT. response, regulatory T cells (Treg), cytokines levels and treatment-related adverse effects were observed.

RESULTS

Of the total 106 patients, 29 patients relapsed at a medium follow-up of 22.9(0.8-63.3) months. The 3-year cumulative relapse rate (RR) was (29.9±8.0) % in auto-HSCT group and (32.7±6.8) % in allo-HSCT group. There were no significant differences in RR and overall survival (OS) between auto-HSCT and allo-HSCT groups, even of stratified risk groups. In standard risk group, 3-year OS was (77.1±13.2) % in auto-HSCT group and (90.9±8.7) % in allo-HSCT group (P=0.739). In high-risk group, 3-year OS was (68.7±10.8) % after auto-HSCT and (45.2±8.5) % after allo-HSCT (P=0.094).

CONCLUSION

Due to acceptable RR and OS, adult ALL patients with no MRD before HSCT showed favorable survival. Auto-HSCT may be a considerable choice for adult ALL patients with negative MRD when lacking of donors for allo-HSCT.

T-cell-replete haploidentical transplantation versus autologous stem cell transplantation in adult acute leukemia: a matched pair analysis

Adult patients with acute leukemia in need of a transplant but without a genoidentical donor are usually considered upfront for transplantation with stem cells from any other allogeneic source, rather than autologous stem cell transplantation. We used data from the European Society for Blood and Marrow Transplantation and performed a matched pair analysis on 188 T-cell-replete haploidentical and 356 autologous transplants done from January 2007 to December 2012, using age, diagnosis, disease status, cytogenetics, and interval from diagnosis to transplant as matching factors. "Haploidentical expert" centers were defined as having reported more than five haploidentical transplants for acute leukemia (median value for the study period). The median follow-up was 28 months. Multivariate analyses, including type of transplant categorized into three classes ("haploidentical regular", "haploidentical expert" and autologous), conditioning intensity (reduced intensity versus myeloablative conditioning) and the random effect taking into account associations related to matching, showed that non-relapse mortality was higher following haploidentical transplants in expert (HR: 4.7; P=0.00004) and regular (HR: 8.98; P<10(-5)) centers. Relapse incidence for haploidentical transplants was lower in expert centers (HR:0.39; P=0.0003) but in regular centers was similar to that for autologous transplants. Leukemia-free survival and overall survival rates were higher following autologous transplantation than haploidentical transplants in regular centers (HR: 1.63; P=0.008 and HR: 2.31; P=0.0002 respectively) but similar to those following haploidentical transplants in expert centers. We conclude that autologous stem cell transplantation should presently be considered as a possible alternative to haploidentical transplantation in regular centers that have not developed a specific expert program.

Prognostic impact of minimal residual disease in adult acute lymphoblastic leukemia

SUMMARY 

While adult acute lymphoblastic leukemia (ALL) is curable in 40–50% of the patients, the individual prognosis is rather unpredictable due to associated biological and clinical risk factors. In both B- and T-precursor ALL, minimal residual disease (MRD) represents the most sensitive prognostic marker, useful to support critical treatment decisions, ranging from allogeneic stem cell transplantation in patients with inadequate MRD response to chemotherapy only in MRD responsive ones. This optimized risk-adapted strategy allows to spare transplant-associated morbidity and mortality in patients curable by chemotherapy. Further progress is expected from the integration of the MRD-based strategy with improved pediatric-type regimens and novel targeting agents for discrete ALL subsets. These changes are increasing the cure rate to above 50%.

Pre-transplant achievement of negativity in minimal residual disease and French-American-British L1 morphology predict superior outcome after allogeneic transplant for Philadelphia chromosome positive acute lymphoblastic leukemia: an analysis of Southeast Asian patients

To better understand predictive factors and improve the clinical outcome of allogeneic transplant for patients with Philadelphia positive acute lymphoblastic leukemia, we analyzed 67 Southeast Asian patients transplanted in our institutions. Multivariate analysis showed that disease status before transplant, year of transplant and, interestingly, French-American-British (FAB) subtype had a significant impact on overall survival (OS) and non-relapse mortality. Patients who were minimal residual disease (MRD) negative at transplant had a 3-year OS of 73% compared to those who were MRD positive (45%) and refractory (0%). The 3-year cumulative incidence of relapse was 18% and 36% for the MRD negative and positive groups, respectively. FAB L1 subtype had a significantly superior 3-year OS of 63% vs. 29% for L2 subtype. Pre-transplant use of a tyrosine kinase inhibitor significantly improved outcomes in univariate but not multivariate analysis, as it served to induce more patients into MRD negativity, which was the factor that directly improved transplant outcome.

Autologous Hematopoietic Stem Cell Transplantation for High-risk Acute Lymphoblastic Leukemia: non-Randomized Study with a maximum Follow-up of more than 22 Years

OBJECTIVE

To evaluate the efficacy and toxicity of autologous hematopoietic stem cell transplantation (AHSCT) for high-risk acute lymphoblastic leukemia (ALL).

MATERIAL AND METHODS

Overall, 128 high-risk ALL patients at a median age of 26 years (range 18-56 years) at diagnosis received AHSCT between 1991-2008. Induction treatment was anthracycline-based in all patients. Conditioning regimen consisted of CAV (cyclophosphamide, cytarabine, etoposide) in 125 patients whereas 3 subjects received cyclophosphamide and TBI (total body irradiation). Bone marrow was stored for 72 hours in 4°C and re-infused 24 hours after conditioning completion. Bone marrow was a source of stem cells in 119 patients, peripheral blood in 2 and 7 subjects received both bone marrow and peripheral blood.

RESULTS

With a median follow-up after AHSCT of 1.6 years (range 0.1-22.3 years), the probability of leukemia-free survival (LFS) for the whole group at 10 years was 27% and 23% at 20 years. Transplant-related mortality at 100 days after AHSCT was 3.2%. There was a strong tendency for better LFS for MRD-negative patients if compared with patients who had positive or unknown MRD status at AHSCT (32% vs 23% and 25%, respectively; p=0.06). There was no difference in LFS between B- and T-lineage ALL as well as between patients transplanted in first complete remission (CR1) and CR2. LFS at 10 years for patients with Philadelphia-positive (Ph+) ALL at transplant was 20% and this was comparable with subjects with negative and missing Ph status (26% and 28%; p=0.97).

CONCLUSIONS

The results of AHSCT for high-risk ALL remains unsatisfactory with low probability of long-term LFS.

Outcome after HSCT in Philadelphia chromosome positive acute lymphoblastic leukemia in Sweden: a population-based study

Even in the tyrosine kinase inhibitor era, allogeneic hematopoietic stem cell transplantation (HSCT) is regarded as standard care for adult Philadelphia (Ph) positive acute lymphoblastic leukemia (ALL). In this retrospective national study, we have reviewed the outcome after HSCT in Sweden for adult Ph-positive ALL between 2000 and 2009. In total, 51 patients with median age 42 (range 20-66) years underwent HSCT. Mainly allogeneic HSCT was performed (24 related donor, 24 unrelated donor and one cord blood), and only two patients were treated with an autologous HSCT. The 5-year OS was 51 (37-64) %. The probabilities of morphological relapse and non-relapse mortality (NRM) at 5 years were 36 (23-49) and 18 (9-29) %, respectively. For the allogeneic transplanted, the 5-year OS was for patients <40 years 70 (50-90) % and for patients ≥40 years 34 (16-52) %, p = 0.002. The 5-year probability of NRM was for patients <40 years 10 (2-28) % compared to 25 (11-42) % for patients ≥40 years (p = 0.04). Patients with chronic graft-versus-host disease (GVHD) had a 5-year morphological relapse probability of 20 (6-40) % compared to 59 (35-77) % for patients without chronic GVHD (p = 0.03). Age ≥40 years and the absence of chronic GVHD were confirmed as independent negative prognostic factors for relapse and non-relapse mortality in a multivariate analysis although the impact of chronic GVHD was significant only in the older age cohort.

Intravenous busulfan for autologous stem cell transplantation in adult patients with acute myeloid leukemia: a survey of 952 patients on behalf of the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

Oral busulfan is the historical backbone of the busulfan+cyclophosphamide regimen for autologous stem cell transplantation. However intravenous busulfan has more predictable pharmacokinetics and less toxicity than oral busulfan; we, therefore, retrospectively analyzed data from 952 patients with acute myeloid leukemia who received intravenous busulfan for autologous stem cell transplantation. Most patients were male (n=531, 56%), and the median age at transplantation was 50.5 years. Two-year overall survival, leukemia-free survival, and relapse incidence were 67±2%, 53±2%, and 40±2%, respectively. The non-relapse mortality rate at 2 years was 7±1%. Five patients died from veno-occlusive disease. Overall leukemia-free survival and relapse incidence at 2 years did not differ significantly between the 815 patients transplanted in first complete remission (52±2% and 40±2%, respectively) and the 137 patients transplanted in second complete remission (58±5% and 35±5%, respectively). Cytogenetic risk classification and age were significant prognostic factors: the 2-year leukemia-free survival was 63±4% in patients with good risk cytogenetics, 52±3% in those with intermediate risk cytogenetics, and 37 ± 10% in those with poor risk cytogenetics (P=0.01); patients ≤50 years old had better overall survival (77±2% versus 56±3%; P<0.001), leukemia-free survival (61±3% versus 45±3%; P<0.001), relapse incidence (35±2% versus 45±3%; P<0.005), and non-relapse mortality (4±1% versus 10±2%; P<0.001) than older patients. The combination of intravenous busulfan and high-dose melphalan was associated with the best overall survival (75±4%). Our results suggest that the use of intravenous busulfan simplifies the autograft procedure and confirm the usefulness of autologous stem cell transplantation in acute myeloid leukemia. As in allogeneic transplantation, veno-occlusive disease is an uncommon complication after an autograft using intravenous busulfan.

Current and future management of Ph/BCR-ABL positive ALL

Following the introduction of targeted therapy with tyrosine kinase inhibitors (TKI) at the beginning of the past decade, the outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) has dramatically improved. Presently, the use of refined programs with first/second generation TKI's and chemotherapy together with allogeneic stem cell transplantation allow up to 50% of all patients to be cured. Further progress is expected with the new TKI ponatinib, overcoming resistance caused by T315I point mutation, other targeted therapies, autologous transplantation in molecularly negative patients, therapeutic monoclonal antibodies like inotuzumab ozogamicin and blinatumomab, and chimeric antigen receptor-modified T cells. Ph+ ALL could become curable in the near future even without allogeneic stem cell transplantation, minimizing the risk of therapy-related death and improving greatly the quality of patients' life.

Treatment of Philadelphia-positive acute lymphoid leukemia

SUMMARY Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) represents approximately 15–30% of ALL in adults and is characterized by the expression of the fusion protein BCR–ABL with oncogenic activity. Remission and survival rates were lower whereas relapse risk was increased in Ph+ compared with Philadelphia-negative ALL, until remarkable improvements in the management of Ph+ ALL were achieved through the introduction of tyrosine kinase inhibitors that reduce the activity of the BCR–ABL protein. However, in patients achieving complete remission, allogeneic hematopoietic stem cell transplantation is in most cases a mandatory therapeutic step because rate of relapses are still high. This review will illustrate the current therapeutic options for the management of Ph+ ALL and indicate how better curative options may stem from appropriate implementation of tyrosine kinase inhibitors and novel antitumoral agents.