Who Should Receive a Transplant for Acute Lymphoblastic Leukaemia?

[Acute lymphoblastic leukemia in developing countries: Management from the transplant indication (allo/auto) until post-transplant follow-up. Guidelines from the SFGM-TC]

Management of acute lymphoblastic leukemia (ALL) patients in countries with limited resources depends on the means of prognostic stratification, available treatment and logistics. During the 12th annual harmonization workshops of the francophone Society of bone marrow transplantation and cellular therapy (SFGM-TC), a designated working group reviewed the literature in order to elaborate unified guidelines for allogeneic hematopoietic cell transplantation (Allo-HCT) in this disease. Conventional poor prognostic factors can be used to determine the indication of allo-HCT in first remission. Patients lacking a HLA-matched related donor can be allografted with a haploidentical donor allo-HCT if available. Chemotherapy based conditioning regimen can be used if TBI is not available, because the probability to find a radiotherapy department with the capacity for total body irradiation is low. For patients with Philadelphia chromosome positive (Phi+) ALL, post-transplantation tyrosine kinase inhibitors as a systematic maintenance strategy is recommended. Autologous HCT is optional for Phi+ ALL patients with negative minimal residual disease, who not eligible for allo-HCT. Patients with refractory/relapsed disease have a poor prognosis which highlights the importance of acquiring in the future new therapies such as: blinatumumab, inotuzumab, and CAR-T cells.

Feasibility and Outcomes of a Third Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Few therapeutic options are available for patients with acute myeloid or lymphoblastic leukemia (AML/ALL) relapsing after a second allogeneic stem cell transplantation (alloSCT2). In selected patients a third allogeneic stem cell transplantation (alloSCT3) has been used, but no detailed analysis is available so far. The European Society for Blood and Marrow Transplantation (EBMT) registry was screened for patients with acute leukemia (AL) receiving alloSCT3 from an identical or alternative donor to treat AL in either haematological relapse or disease persistence after alloSCT2 between 2001 and 2018. Feasibility, efficacy, outcome, and risk factors of this approach were analyzed retrospectively. Forty-five patients (median age, 37 years, range 12-71) with AML (n=34) or ALL (n=11) were identified. Eleven patients received alloSCT3 in complete remission (CR), 34 had active disease. Fifteen patients were transplanted from the same donor at all three transplants, 30 patients had at least 2 different donors. Between alloSCT2 and alloSCT3, the donor was changed in 25 patients. After alloSCT3, 38 patients engrafted, and 26 achieved CR or CR with incomplete hematological reconstitution (CRi). Acute graft-versus-host disease (GvHD) grade II-IV was observed in 19%, chronic GvHD occurred in 13%. After 1-year, cumulative incidences of leukemia relapse and non-relapse mortality were 47% and 42%, respectively. Median progression free and overall survival (PFS/OS) from alloSCT3 were 2.5 and 4 months, respectively, 1-year PFS and OS were 11% and 20%,. Outcome was improved in patients with at least one donor change (1-year PFS/OS: 17%/30%), further factors for better outcome included an unrelated donor for alloSCT3, Karnofsky performance score >80, and more recent year of alloSCT3. Only patients with AML achieved >1 year OS. In conclusion, results after a third alloSCT are poor, limiting this procedure to few, highly selected patients. Recurrent relapses of acute leukemia after alloSCT remain an unmet therapeutic need.

Haploidentical transplant in adult patients with acute lymphoblastic leukemia in Argentina: a comparison with matched related and unrelated donors

We aimed at analyzing the outcome of allogeneic stem cell transplant (ASCT) in adult patients with acute lymphoblastic leukemia (ALL), comparing Haploidentical (Haplo) with HLA-matched (sibling and unrelated) donors. Between 2008 and 2017, we collected data from 236 patients (median age 31 years; range 16-64; 90% HCT-CI 0-1) who underwent unmanipulated ASCT in first complete remission and subsequent remissions in 15 Argentinian centers. Donors were HLA-matched (n = 175; 74%) and Haplo (n = 61; 26%). Two-year overall survival (OS) was 55% (95% CI 47-63) for the HLA-matched group and 49% (95% CI 34-62) for the Haplo group (p = 0.351). For OS, crude HR, adjusted HR for covariates (HR 1.24; 95% CI 0.77-1.99; p = 0.363) and HR including a propensity score in the model (HR 1.22; 95% CI 0.71-2.08; p = 0.414) showed no impact of donor category on the OS. No difference was found in terms of nonrelapse mortality, relapse, leukemia-free survival, and grade 3-4 acute graft-versus-host disease (GVHD); 2-year incidence of chronic GVHD was higher in HLA-matched vs Haplo group (p = 0.028). Patients with ALL who underwent ASCT were young subjects with low HCT-CI. In this setting, a Haplo donor represents an alternative widely available in the absence of an HLA-matched donor. Relapse remains a challenge for all donor categories.

Approach to the Adult Acute Lymphoblastic Leukemia Patient

During recent decades, understanding of the molecular mechanisms of acute lymphoblastic leukemia (ALL) has improved considerably, resulting in better risk stratification of patients and increased survival rates. Age, white blood cell count (WBC), and specific genetic abnormalities are the most important factors that define risk groups for ALL. State-of-the-art diagnosis of ALL requires cytological and cytogenetical analyses, as well as flow cytometry and high-throughput sequencing assays. An important aspect in the diagnostic characterization of patients with ALL is the identification of the Philadelphia (Ph) chromosome, which warrants the addition of tyrosine kinase inhibitors (TKI) to the chemotherapy backbone. Data that support the benefit of hematopoietic stem cell transplantation (HSCT) in high risk patient subsets or in late relapse patients are still questioned and have yet to be determined conclusive. This article presents the newly published data in ALL workup and treatment, putting it into perspective for the attending physician in hematology and oncology.

Hematopoietic Cell Transplantation in Young Adult Acute Lymphoblastic Leukemia: A United States Population-Level Analysis

In this population-based evaluation of adolescents and young adults (AYA) acute lymphoblastic leukemia (ALL), we describe patterns of care (POC) and outcomes regarding hematopoietic cell transplantation (HCT) in first complete remission (CR1). Data were abstracted from the 2013 United States Surveillance, Epidemiology, and End Results POC study; newly diagnosed AYA ALL were included. Multivariable logistic regression evaluated associations with HCT in CR1; Cox proportional hazards regression evaluated survival associations. Of 399 AYAs with ALL included, 102 (28.5%) underwent HCT in CR1. High-risk cytogenetics (odds ratio [OR] = 4.86, 95% confidence interval [CI] = 3.02-7.83) and hyper-cyclophosphamide, vincristine, adriamycin, and dexamethasone (CVAD) induction (OR = 1.84, 95% CI = 1.07-3.16) were associated with HCT in CR1. Two-year cumulative incidence of relapse, relapse-free survival (RFS), and overall survival (OS) of the entire cohort were 28.3% (95% CI = 23.4-33.4), 69.3% (95% CI = 63.6-74.3%), and 84.1% (95% CI = 79.7-87.5), respectively. Two-year RFS was significantly higher in patients receiving CR1 HCT relative to chemotherapy (83.6%, 95% CI = 72.6-90.5% vs. 64.3%, 95% CI = 57.5-70.3), but no difference was seen in 2-year OS (88.9%, 95% CI = 80.8-93.7 vs. 82.5%, 95% CI = 77.2-86.7). Treatment at a nonteaching hospital was independently associated with inferior OS (hazard ratio = 2.15, 95% CI = 1.23-3.76). Although the ALL landscape is changing, these data provide a snapshot of the use and outcomes of HCT for AYA ALL across the United States.

Reduced Intensity Conditioning Allogeneic Hematopoietic Stem Cell Transplantation for Acute Lymphoblastic Leukemia; Current Evidence, and Improving Outcomes Going Forward

PURPOSE OF REVIEW

Outcomes for older adults with acute lymphoblastic leukemia (ALL) remain poor, and allogeneic hematopoietic stem cell transplant (HSCT) remains a potentially curative modality. However, benefits are offset by high rates of non-relapse mortality (NRM) in patients undergoing myeloablative conditioning (MAC) regimens. Reduced intensity conditioning (RIC) regimens can extend this therapy to adults who are unfit for MAC, although at the cost of higher relapse rates. In this review, we discuss evidence to support the usage of RIC regimens, controversies, and potential strategies to improve transplant outcomes going forward.

RECENT FINDINGS

Several novel therapies have recently been approved for the treatment of relapsed ALL and may play an important role in bridging adults with residual disease to RIC transplant. Assessing response to initial therapy via minimal residual disease (MRD) monitoring may determine which patients will derive the most benefit from allogeneic HSCT. Reduced intensity allogeneic HSCT remains a potentially curative therapy that can be offered to older adults however challenges remain. Going forward, MRD testing and novel therapies may help better select which patients should proceed to transplant and assist in getting those patients to transplant with optimally controlled disease.

Chimeric Antigen Receptor T-Cells for the Treatment of B-Cell Acute Lymphoblastic Leukemia

Chimeric antigen receptor (CAR) T-cell technology has seen a rapid development over the last decade mostly due to the potential that these cells may have in treating malignant diseases. It is a generally accepted principle that very few therapeutic compounds deliver a clinical response without treatment-related toxicity, and studies have shown that CAR T-cells are not an exception to this rule. While large multinational drug companies are currently investigating the potential role of CAR T-cells in hematological oncology, the potential of such cellular therapies are being recognized worldwide as they are expected to expand in the patient to support the establishment of the immune memory, provide a continuous surveillance to prevent and/or treat a relapse, and keep the targeted malignant cell subpopulation in check. In this article, we present the possible advantages of using CAR T-cells in treating acute lymphoblastic leukemia, presenting the technology and the current knowledge in their preclinical and early clinical trial use. Thus, this article first presents the main present-day knowledge on the standard of care for acute lymphoblastic leukemia. Afterward, current knowledge is presented about the use of CAR T-cells in cancer immunotherapy, describing their design, the molecular constructs, and the preclinical data on murine models to properly explain the background for their clinical use. Last, but certainly not least, this article presents the use of CAR T-cells for the immunotherapy of B-cell acute lymphoblastic leukemia, describing both their potential clinical advantages and the possible side effects.

Current challenges and opportunities in treating adult patients with Philadelphia-negative acute lymphoblastic leukaemia

Significant advances have been made in recent years in the field of Philadelphia-negative acute lymphoblastic leukaemia (ALL). New insights into the biology and genetics of ALL as well as novel clinical observations and new drugs are changing the way we diagnose, risk-stratify and treat adult patients with ALL. New genetic subtypes and alterations refine risk stratification and uncover new actionable therapeutic targets. The incorporation of more intensive, paediatric and paediatric-inspired approaches for young adults seem to have a positive impact on survival in this population. Minimal residual disease at different time points can assist in tailoring risk-adapted interventions for patients based on individual response. Finally, novel targeted approaches with monoclonal antibodies, immunotherapies and small molecules are moving through clinical development and entering the clinic. The aim of this review is to consolidate the abundance of emerging data and to review and revisit the concepts of risk-stratification, choice of induction and post-remission strategies as well as to discuss and update the approach to specific populations with ALL, such as young adult, elderly/unfit and relapsed/refractory patients with ALL.

Concise Review: Emerging Principles from the Clinical Application of Chimeric Antigen Receptor T Cell Therapies for B Cell Malignancies

Gene-engineered T cell therapies are soon to be United States Food and Drug Administration (FDA) approved for at least two types of B cell malignancies in pediatric and adult patients, in the form of CD19 targeted chimeric antigen receptor T (CAR T) cell therapy. This represents a triumph of a true bench to bedside clinical translation of a therapy that was conceived of in the early 1990s. Clinical results have demonstrated efficacious responses in patients with the CD19 positive diseases B cell acute lymphoblastic leukemia and diffuse large B cell lymphoma. However, significant challenges have emerged, including worrisome immune-related toxicities, therapy resistance, and understanding how to administer CD19 CAR T cells in clinical practice. Although much remains to be learned, pioneering clinical trials have led to foundational insights about the clinical translation of this novel therapy. Here, we review the "lessons learned" from the pre-clinical and human experience with CAR T cell therapy. Stem Cells 2018;36:36-44.