Adverse prognostic significance of CD20 expression in adults with Philadelphia chromosome-negative B-cell precursor acute lymphoblastic leukemia

Diagnosis, prognostic factors, and assessment of ALL in adults: 2024 ELN recommendations from a European expert panel

ABSTRACT

Working groups of the European LeukemiaNet have published several important consensus guidelines. Acute lymphoblastic leukemia (ALL) has many different clinical and biological subgroups and the knowledge on disease biology and therapeutic options is increasing exponentially. The European Working Group for Adult ALL has therefore summarized the current state of the art and provided comprehensive consensus recommendations for diagnostic approaches, biologic and clinical characterization, prognostic factors, and risk stratification as well as definitions of endpoints and outcomes. Aspects of treatment, management of subgroups and specific situations, aftercare, and supportive care are covered in a separate publication. The present recommendation intends to provide guidance for the initial management of adult patients with ALL and to define principles as a basis for future collaborative research.

Asciminib Maintains Antibody-Dependent Cellular Cytotoxicity against Leukemic Blasts

B cell acute lymphoblastic leukemia (B-ALL) is characterized by an accumulation of malignant precursor cells. Treatment consists of multiagent chemotherapy followed by allogeneic stem cell transplantation in high-risk patients. In addition, patients bearing the BCR-ABL1 fusion gene receive concomitant tyrosine kinase inhibitor (TKI) therapy. On the other hand, monoclonal antibody therapy is increasingly used in both clinical trials and real-world settings. The introduction of rituximab has improved the outcomes in CD20 positive cases. Other monoclonal antibodies, such as tafasitamab (anti-CD19), obinutuzumab (anti-CD20) and epratuzumab (anti-CD22) have been tested in trials (NCT05366218, NCT04920968, NCT00098839). The efficacy of monoclonal antibodies is based, at least in part, on their ability to induce antibody-dependent cellular cytotoxicity (ADCC). Combination treatments, e.g., chemotherapy and TKI, should therefore be screened for potential interference with ADCC. Here, we report on in vitro data using BCR-ABL1 positive and negative B-ALL cell lines treated with rituximab and TKI. NK cell activation, proliferation, degranulation, cytokine release and tumor cell lysis were analyzed. In contrast to ATP site inhibitors such as dasatinib and ponatinib, the novel first-in-class selective allosteric ABL myristoyl pocket (STAMP) inhibitor asciminib did not significantly impact ADCC in our settings. Our results suggest that asciminib should be considered in clinical trials.

Ponatinib Improved the Prognosis of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: A Japanese Single-Center Cohort Study

Introduction The overall survival (OS) of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) has improved with the combination of tyrosine kinase inhibitor (TKI) with intensive chemotherapy. In recent years, there has been increased interest in the possibility of long-term survival without allogeneic hematopoietic stem cell transplantation (HSCT) or maintenance therapy. The aim of this study was to determine the effectiveness of treatment and the resultant outcomes in Ph+ALL patients using real-world data. Methods We performed a single-center retrospective analysis utilizing Akita University Hospital data (Akita, Japan) from November 2000 to June 2023 to evaluate the outcomes of TKI with intensive chemotherapy for Ph+ALL. Results Twenty-three patients with Ph+ALL were treated with intensive chemotherapy combined with TKI, including six imatinib, four dasatinib, and 13 ponatinib. The median patient age was 53 years (range; 28-67). Eighteen patients (78%) achieved complete molecular remission (CMR) within three months. HSCT was performed in 16 patients (70%), all of whom did not receive post-transplant TKI maintenance therapy. Six of the seven patients who did not undergo HSCT received maintenance therapy with ponatinib after intensive chemotherapy. The three-year OS was 81%. Ponatinib treatment resulted in a much higher OS rate than imatinib/dasatinib (100% vs. 60%; P=0.011). CMR within three months was identified as a prognostic factor for molecular relapse-free survival (hazard ratio (HR)=0.22; P=0.027). CD20 positivity was identified as a risk factor for hematological relapse (HR=5.2, P=0.032). Conclusion Even in a single-center cohort study, ponatinib, as a combination TKI with intensive chemotherapy or maintenance therapy, may improve the prognosis of Ph+ALL. Patients with CMR within three months might not necessarily need to receive HSCT, but a subsequent treatment-free status could have been achieved only by HSCT. Furthermore, CD20 positivity may be a useful biomarker for future treatment decisions in patients with Ph+ALL.

Immunotherapy in Acute Leukemias: Past Success Paves the Way for Future Progress

Immunotherapy as a cancer treatment modality has undergone recent widespread proliferation across all cancer types, especially amongst patients with solid tumors. However, the longest tenured immunotherapy approach to cancer is allogeneic stem cell transplantation (allo-SCT) for two hematologic malignancies: acute myeloid and acute lymphoid leukemia (AML and ALL, respectively). While allo-SCT remains a standard of care for eligible patients, recent advances/applications of monoclonal antibodies, immune checkpoint inhibitors, bispecific T-cell engagers (BiTEs), and CAR T-cell therapy are changing the treatment landscape for these acute leukemias by either direct to tumor immune targeting or through decreased toxicities that expand patient eligibility. Pre-clinical data and clinical trials have shown promising results for novel immunotherapies in acute leukemia, and multiple ongoing trials are investigating these novel approaches. While there have been promising results with these approaches, particularly in the relapsed/refractory setting, there remain challenges in optimizing the use of these therapies, such as managing cytokine release syndrome and other immune-related toxicities. Immunotherapy is a rapidly evolving field in the treatment of acute leukemia and has the potential to significantly impact the management of both AML and ALL. This review highlights the history of immunotherapy in the treatment of acute leukemias, the evolution of immunotherapy into more targeted approaches, the potential benefits and limitations of different immune targeting approaches, and ongoing research and development in the field.

Prognostic Significance of CD20 Expression in Children with Philadelphia Chromosome-Negative B-Cell Precursor Acute Lymphoblastic Leukemia

INTRODUCTION

The prognostic significance of CD20 in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) remains unclear. Therefore, in this study, we evaluated the prognostic value of CD20 expression in leukemia blasts in pediatric BCP-ALL at our institute.

METHODS

Between 2005 and 2017, 796 children with newly diagnosed Philadelphia-negative BCP-ALL were enrolled consecutively; clinical characteristics and treatment outcomes were analyzed and compared between CD20-positive and CD20-negative groups.

RESULTS

CD20 positivity was observed in 22.7% of enrolled patients. The analysis of overall and event-free survival showed that white blood cell count ≥50 × 109/L, no ETV6-RUNX1, day 33 minimal residual disease (MRD) ≥0.1%, and week 12 MRD ≥0.01% were independent risk factors. Meanwhile, in the CD20-positive group, week 12 MRD ≥0.01% was the only factor associated with long-term survival. Moreover, subgroup analysis revealed that in patients with extramedullary involvement (p = 0.047), MRD ≥0.1% on day 33 (p = 0.032), or MRD ≥0.01% at week 12 (p = 0.004), CD20 expression led to a poorer outcome compared to those without CD20 expression.

CONCLUSIONS

Pediatric BCP-ALL with CD20 expression had unique clinicopathological characteristics, and MRD remained the major prognostic factor. CD20 expression had no prognostic value in pediatric BCP-ALL.

Monoclonal antibodies: new chance in the management of B-cell acute lymphoblastic leukemia

OBJECTIVES

This review aims to see the progress of several clinically-used monoclonal antibodies in treating ALL patients and how they improved patients' outcomes.

METHODS

We searched Web of Science, Elsevier and PubMed for relevant published studies, and summarized eligible evidence on the management of newly-diagnosed and relapsed or refractory ALL with monoclonal antibodies. Ongoing trials were identified from ClinicalTrials.gov.

RESULTS

Rituximab, an anti-CD20 monoclonal antibody, prolonged patients' complete remission duration and overall survival when combined with hyper-CVAD regimen. Another anti-CD20 monoclonal antibody, Ofatumumab, was reported to have similar benefits. Blinatumomab allows endogenous CD3-positive cytotoxic T cells to target and eliminate CD19-positive blasts. FDA has approved its efficacy in patients with R/R B-ALL and eliminating minimal residual disease (MRD). It serves as a bridge to eradicate MRD before transplantation, and may also be a new choice for patients unable to undergo transplantation. An anti-CD22 monoclonal antibody named Inotuzumab Ozogamicin showed great improvement in patients' outcome, but its toxicity to liver is also worthy of our attention.

CONCLUSION

Monoclonal antibodies are proven to be a promising immunotherapeutic strategy to improve ALL patients' outcome in the long term. There's still a need for individualized treatment with effective and well-tolerated medicines.Trial registration: ClinicalTrials.gov identifier: NCT01363128.Trial registration: ClinicalTrials.gov identifier: NCT01466179.Trial registration: ClinicalTrials.gov identifier: NCT02013167.Trial registration: ClinicalTrials.gov identifier: NCT02000427.Trial registration: ClinicalTrials.gov identifier: NCT01564784.Trial registration: ClinicalTrials.gov identifier: NCT03677596.Trial registration: ClinicalTrials.gov identifier: NCT01363297.Trial registration: ClinicalTrials.gov identifier: NCT02981628.Trial registration: ClinicalTrials.gov identifier: NCT03094611.Trial registration: ClinicalTrials.gov identifier: NCT01371630.Trial registration: ClinicalTrials.gov identifier: NCT04224571.Trial registration: ClinicalTrials.gov identifier: NCT02458014.Trial registration: ClinicalTrials.gov identifier: NCT04546399.Trial registration: ClinicalTrials.gov identifier: NCT02879695.Trial registration: ClinicalTrials.gov identifier: NCT03913559.Trial registration: ClinicalTrials.gov identifier: NCT03441061.Trial registration: ClinicalTrials.gov identifier: NCT03739814.Trial registration: ClinicalTrials.gov identifier: NCT02877303.Trial registration: ClinicalTrials.gov identifier: NCT03698552.Trial registration: ClinicalTrials.gov identifier: NCT04601584.Trial registration: ClinicalTrials.gov identifier: NCT04684147.Trial registration: ClinicalTrials.gov identifier: NCT04681105.

The different predictive effects of the intensity and proportion of CD20 expression on the prognosis of B-lineage acute lymphocyte leukemia

The prognostic effects of the CD20 positivity have been studied extensively in B‐lineage acute lymphocyte leukemia (B‐ALL) patients, but the results remain controversial. The aim of this study is to investigate the different predictive effects of the intensity and proportion of CD20 expression on the prognosis for B‐ALL patients by retrospective analysis. The mean fluorescence intensity (MFI) and percentage of CD20 on B‐ALL cells from 206 patients with B‐ALL were dynamically measured by flow cytometry, and their optimal cut‐off values were determined using the receiver operating characteristic curve. Changes in MFI and percentage of CD20 at various time points and their relationship with prognosis were analyzed. We found that a low baseline CD20 MFI or high CD20 proportion was significantly associated with shorter 5‐year overall survival and progression‐free survival, and the combination of these two factors could more accurately predict worse survival for B‐ALL patients. Furthermore, low CD20 MFI or a high CD20 proportion had different predictive effects for ALL patients with different clinical characteristics and could serve as an independent risk factor for adverse prognosis. There were significant decreases in both the intensity and proportion of CD20 after recurrence in the absence of rituximab treatment, particularly with CD20 intensity. Notably, the decrease of CD20 intensity after recurrence indicated a more shortened survival time. Finally, we conclude that a low intensity or high proportion of CD20 expression may be used as an indicator for inferior prognosis for B‐ALL patients. CD20 intensity is more likely to be a more universal biomarker for worse prognosis.

Addition of four doses of rituximab to standard induction chemotherapy in adult patients with precursor B-cell acute lymphoblastic leukaemia (UKALL14): a phase 3, multicentre, randomised controlled trial

BACKGROUND

Treatment for adults with acute lymphoblastic leukaemia requires improvement. UKALL14 was a UK National Cancer Research Institute Adult ALL group study that aimed to determine the benefit of adding the anti-CD20 monoclonal antibody, rituximab, to the therapy of adults with de novo B-precursor acute lymphoblastic leukaemia.

METHODS

This was an investigator-initiated, phase 3, randomised controlled trial done in all UK National Health Service Centres treating patients with acute lymphoblastic leukaemia (65 centres). Patients were aged 25-65 years with de-novo BCR-ABL1-negative acute lymphoblastic leukaemia. Patients with de-novo BCR-ABL1-positive acute lymphoblastic leukaemia were eligible if they were aged 19-65 years. Participants were randomly assigned (1:1) to standard-of-care induction therapy or standard-of-care induction therapy plus four doses of intravenous rituximab (375 mg/m² on days 3, 10, 17, and 24). Randomisation used minimisation and was stratified by sex, age, and white blood cell count. No masking was used for patients, clinicians, or staff (including the trial statistician), although the central laboratory analysing minimal residual disease and CD20 was masked to treatment allocation. The primary endpoint was event-free survival in the intention-to-treat population. Safety was assessed in all participants who started trial treatment. This study is registered with ClincialTrials.gov, NCT01085617.

FINDINGS

Between April 19, 2012, and July 10, 2017, 586 patients were randomly assigned to standard of care (n=292) or standard of care plus rituximab (n=294). Nine patients were excluded from the final analysis due to misdiagnosis (standard of care n=4, standard of care plus rituximab n=5). In the standard-of-care group, median age was 45 years (IQR 22-65), 159 (55%) of 292 participants were male, 128 (44%) were female, one (<1%) was intersex, and 143 (59%) of 244 participants had high-risk cytogenetics. In the standard-of-care plus rituximab group, median age was 46 years (IQR 23-65), 159 (55%) of 294 participants were male, 130 (45%) were female, and 140 (60%) of 235 participants had high-risk cytogenetics. After a median follow-up of 53·7 months (IQR 40·3-70·4), 3-year event-free survival was 43·7% (95% CI 37·8-49·5) for standard of care versus 51·4% (45·4-57·1) for standard of care plus rituximab (hazard ratio [HR] 0·85 [95% CI 0·69-1·06]; p=0·14). The most common adverse events were infections and cytopenias, with no difference between the groups in the rates of adverse events. There were 11 (4%) fatal (grade 5) events in induction phases 1 and 2 in the standard-of-care group and 13 (5%) events in the standard-of-care plus rituximab group). 3-year non-relapse mortality was 23·7% (95% CI 19·0-29·4) in the standard-of-care group versus 20·6% (16·2-25·9) in the standard-of-care plus rituximab group (HR 0·88 [95% CI 0·62-1·26]; p=0·49).

INTERPRETATION

Standard of care plus four doses of rituximab did not significantly improve event-free survival over standard of care. Rituximab is beneficial in acute lymphoblastic leukaemia but four doses during induction is likely to be insufficient.

FUNDING

Cancer Research UK and Blood Cancer UK.

Evaluating outcomes of adult patients with acute lymphoblastic leukemia and lymphoblastic lymphoma treated on the GMALL 07/2003 protocol

Chemotherapy-based approaches still constitute an essential feature in the treatment paradigm of adult acute lymphoblastic leukemia (ALL). The German Multicenter Study Group (GMALL) is a well-established protocol for ALL. In this study, we assessed our recent experience with the GMALL 07/2003 protocol reviewing all adult ALL patients who were treated with GMALL in three major centers in Israel during 2007-2020. The analysis comprised 127 patients with a median age of 41 years (range 17-83). Sixty-two were B-ALL (49%), 20 (16%) patients were Philadelphia chromosome positive ALL, and 45 (35%) were T-ALL. The 2-year and 5-year overall survival rates were 71% and 57%, respectively. The 2-year relapse rate was 30% with 2-year and 5-year leukemia-free survival rates of 59% and 50%, respectively. Adolescents and young adults experienced significantly longer overall survival (84 months versus 51 months; p=0.047) as well as leukemia-free survival compared with older patients (66 months versus 54 months, p=0.003; hazard ratio=0.39, 95% confidence interval, 0.19-0.79; p=0.009). T-ALL patients had longer survival compared to B-ALL patients while survival was comparable among Philadelphia chromosome positive patients and Philadelphia chromosome negative patients. An increased number of cytogenetic clones at diagnosis were tightly associated with adverse prognosis (15-month survival for ≥2 clones versus 81 months for normal karyotype; p=0.003). Positive measurable residual disease studies following consolidation were predictive for increased risk of relapse (64% versus 22%; p=0.003) and shorter leukemia-free survival (11 months versus 42 months; p=0.0003). While GMALL is an effective adult regimen, a substantial patient segment still experiences relapse.

Immunotherapies in acute leukemia

In the past decade, immunotherapy has emerged as one of the most promising field of therapeutic progress in acute leukemia. Antibody-drug conjugates are now combined to standard chemotherapy backbones in both acute myeloid (AML) and lymphoblastic leukemia (ALL). CD19 targeting immune cell engagers and chimeric antigen receptor (CAR) T-cells have been approved in relapsed/refractory B-cell acute lymphoblastic leukemia and pave the way to promising developments in acute myeloid leukemia. Next generation immune checkpoint inhibitors targeting TIM-3 or CD47 binding by SIRPα on macrophages are tested in combination to hypomethylating agents to improve survival of unfit AML patients with acceptable safety profiles. This review summarizes the antibody-derived strategies developed in the field of acute leukemias with a specific focus on recently approved drugs.

Acute Lymphoblastic Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Radiation-Free myeloablative allogeneic hematopoietic stem cell transplantation for adult acute lymphoblastic leukemia: A comparison of outcomes between patients with and without central nervous system involvement

For patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), total body irradiation (TBI) has been particularly advocated as a part of the conditioning regimen in case of extramedullary involvement in sanctuary sites such as the central nervous system (CNS), to ensure greater tissue penetration. In resource-limited countries lacking TBI facilities; however, ALL patients undergo radiation-free myeloablative conditioning, though its impacts on post-HSCT outcomes of the patients with pre-HSCT CNS involvement have not been analyzed. In this 14-year series of 278 adult (> 18 y) ALL patients undergoing TBI-free busulfan/cyclophosphamide conditioning allo-HSCT, we found that the long-term probabilities of overall survival, disease free survival, relapse and non-relapse mortality were not significantly different between CNS-involved and CNS-spared patients. Moreover, there was no statistically significant difference in the incidence of post-HSCT CNS relapse between CNS-involved and CNS-spared patients. Pre-HSCT cranial radiation therapy (CRT) showed no significant preventive effect on the likelihood of post-HSCT CNS relapse. Through multivariable regression analysis, grade III-IV acute graft-versus-host disease (GvHD), extensive chronic GvHD and post-HSCT relapse were ascertained as independent determinants of mortality (Adj.R² = 53.9 %, F_(12,265) = 28.1, P < 0.001), while other parameters including Philadelphia translocation, pre-HSCT CNS involvement and CRT were found to have no independent effect. Although this study was not an attempt to compare TBI-based vs. non-TBI conditioning, the TBI-free myeloablative allo-HSCT was shown to be feasible and an option for adult ALL patients with CNS involvement, considering the comparable outcomes between patients with and without CNS involvement.

Hyper-CVAD plus ofatumumab versus hyper-CVAD plus rituximab as frontline therapy in adults with Philadelphia chromosome-negative acute lymphoblastic leukemia: A propensity score analysis

BACKGROUND

The outcome of hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone plus ofatumumab hyper-CVAD + ofatumumab (hyper-CVAD + ofatumumab) has not been compared with the outcome of hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone plus ofatumumab hyper-CVAD plus rituximab (hyper-CVAD + Rituximab) in Philadelphia chromosome-negative acute lymphoblastic leukemia (ALL) in a randomized clinical trial.

METHODS

The authors compared the outcomes of 69 patients treated with hyper-CVAD + ofatumumab and 95 historical-control patients treated with hyper-CVAD + Rituximab. Historical-control patients were treated with hyper-CVAD + Rituximab if they had CD20 expression ≥ 20%. Ofatumumab (day 1 of course 1, 300 mg intravenously; subsequent doses, 2000 mg intravenously) was administered on days 1 and 11 of courses 1 and 3 and on days 1 and 8 of courses 2 and 4 for a total of 8 doses. A propensity score analysis with inverse probability of treatment weighting (IPTW) was performed to adjust for baseline covariates between groups.

RESULTS

The median event-free survival with stem cell transplantation (SCT) censoring was 33 and 65 months with hyper-CVAD + Rituximab and hyper-CVAD + ofatumumab, respectively (crude P = .064; IPTW P = .054). The median overall survival with SCT censoring was 52 months and not reached, respectively (crude P = .087; IPTW P = .097).

CONCLUSIONS

Hyper-CVAD + ofatumumab was associated with better outcomes than hyper-CVAD + Rituximab among patients with newly diagnosed Philadelphia chromosome-negative ALL.

Indications for Allogeneic HCT in Adults with Acute Lymphoblastic Leukemia in First Complete Remission

OPINION STATEMENT

Acute lymphoblastic leukemia (ALL) in adults is associated with poor outcomes as compared to children when treated with chemotherapy, leading to a considerably inferior cure rate. Historically, consolidation with allogeneic hematopoietic cell transplant (alloHCT) was routinely recommended for eligible adults with ALL in first complete remission (CR1) if a donor was available, since randomized studies showed superiority over continuing chemotherapy. With the increasing use of pediatric-inspired frontline regimens in young adults with ALL and the availability of novel salvage agents for relapsed/refractory B-cell ALL that have high potential in inducing a second CR, the role of early alloHCT in the treatment paradigm for ALL needs to be reevaluated, and the decision should be individualized for each patient. Simultaneously, alloHCT has evolved considerably lately, and historical randomized studies that have proven the benefit of alloHCT in adults with ALL in CR1 did not included the increasing use of reduced intensity conditioning and haploidentical transplants, and therefore, data may not entirely apply. Nowadays, detectable minimal residual disease (MRD) is the most prognostic determinant of ALL outcome and should be a major consideration in the decision to perform alloHcT in CR1. Nonetheless, other biological and clinical factors remain relevant and can support the complex decision-making. Such factors include high-risk leukemia genetics, the type of administered chemotherapy regimen and the ability of the patient to tolerate all key components of the regimen, and the availability of effective salvage therapies that allow alloHCT to be performed in CR2 in case of relapse after chemotherapy.

Recent Advances in Managing Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is characterized by chromosomal translocations and somatic mutations that lead to leukemogenesis. The incorporation of pediatric-type regimens has improved survival in young adults, and the incorporation of tyrosine kinase inhibitors for patients with Philadelphia chromosome-positive disease has led to further improvements in outcomes. However, older patients often have poor-risk biology and reduced tolerance to chemotherapy, leading to lower remission rates and overall survival. Regardless of age, patients with relapsed or refractory ALL have extremely poor outcomes. The advent of next-generation sequencing has facilitated the revolution in understanding the genetics of ALL. New genetic risk stratification together with the ability to measure minimal residual disease, leukemic blasts left behind after cytotoxic chemotherapy, has led to better tools to guide postremission approaches-that is, consolidation chemotherapy or allogeneic stem cell transplantation. In this article, we discuss the evolving and complex genetic landscape of ALL and the emerging therapeutic options for patients with relapsed/refractory ALL and older patients with ALL.

Recent Advances in Adult Acute Lymphoblastic Leukemia

PURPOSE OF REVIEW

This article reviews the recent advances in the pathophysiology and management of acute lymphoblastic leukemia (ALL) in adults.

RECENT FINDINGS

Addition of rituximab to standard chemotherapy improves survival in the frontline treatment of B cell ALL, and measurable residual disease (MRD) is the most important prognostic factor. Tyrosine kinase inhibitors (TKI), particularly ponatinib, in combination with Hyper-CVAD significantly improve outcomes in Ph + ALL challenging the benefit of allogeneic stem cell transplant in first line for these patients. Blinatumomab, inotuzumab ozogamicin, and chimeric antigen receptor (CAR) T cells are better options than chemotherapy alone for the treatment of relapsed or refractory ALL. Combination of these agents with chemotherapy and their incorporation in the frontline setting show promises to improve cure rates of ALL. Development of monoclonal antibodies, CAR T, and potent TKI has improved the outcome of ALL. Advances in our understanding of ALL biology are expected to bring new therapeutic strategies in the upcoming years.

[CD20 is not a poor prognostic factor for childhood B-lineage acute lymphoblastic leukemia with high white blood cell count]

OBJECTIVE

To study the significance of CD20 combined with white blood cell (WBC) count at diagnosis in the prognosis assessment in children with B-lineage acute lymphoblastic leukemia (ALL).

METHODS

A retrospective analysis was performed on the medical data of 821 B-ALL children who were treated with CCLG-ALL2008 regimen from April 2008 to April 2015. Their survival status was followed up.

RESULTS

Among the 821 children, 547 (66.6%) were negative, while 274 (33.4%) were positive for CD20 expression. Among 694 children with WBC<50×10⁹/L (lower WBC count), the 5-year EFS rates were 65.9%±3.2% and 77.3%±2.0% for CD20 positive and negative patients respectively (P=0.001); the 5-year OS rates were 78.3%±2.9% and 87.5%±1.6% for CD20 positive and negative patients respectively (P=0.005); CD20 positive expression was an independent risk factor for EFS (HR=1.634, P=0.001) and OS (HR=1.761, P=0.005). Among 127 children with WBC>50×10⁹/L (higher WBC count), the 5-year EFS rates was 64.3%±7.7% and 53.7%±5.5% for CD20 positive and negative patients respectively (P=0.135); the 5-year OS rate was 81.4%±6.4% and 58.6%±5.6% for CD20 positive and negative patients respectively (P=0.022); CD20 positive expression was an independent protective factor for OS (HR=0.367, P=0.016).

CONCLUSIONS

In children with B-ALL who are treated with CCLG-ALL2008 regimen, those with CD20 positive expression in lower WBC count at diagnosis have a poor prognosis; however, those with CD20 positive expression in higher WBC count at diagnosis have a better long-time survival.

Hyper-CVAD regimen in combination with ofatumumab as frontline therapy for adults with Philadelphia chromosome-negative B-cell acute lymphoblastic leukaemia: a single-arm, phase 2 trial

BACKGROUND

The addition of rituximab to intensive chemotherapy improves outcomes in patients with B-cell acute lymphoblastic leukaemia. Ofatumumab is an anti-CD20 monoclonal antibody that binds to the small extracellular loop of CD20 and has greater in vitro complement-mediated cytotoxicity than rituximab. In this study, we assessed the activity and safety of ofatumumab in combination with chemotherapy in patients with Philadelphia chromosome (Ph)-negative CD20-positive B-cell acute lymphoblastic leukaemia.

METHODS

This was a single-arm, phase 2 trial done at the MD Anderson Cancer Center (Houston, TX, USA). Patients with newly diagnosed, Ph-negative B-cell acute lymphoblastic leukaemia or lymphoblastic lymphoma with CD20 expression of at least 1% were eligible. Patients were treated with up to eight courses of the hyper-CVAD regimen (hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone) on courses 1, 3, 5, and 7 alternating with high-dose methotrexate and cytarabine on courses 2, 4, 6, and 8. Ofatumumab was administered on days 1 and 11 of courses 1 and 3 and on days 1 and 8 of courses 2 and 4 for a total of eight doses. The first dose of ofatumumab was 300 mg intravenously and all subsequent doses were 2000 mg intravenously. Patients received 30 courses of maintenance therapy with 6-mercaptopurine, vincristine, methotrexate, and prednisone (POMP), with four intensification courses (high-dose methotrexate plus L-asparaginase and hyper-CVAD plus ofatumumab on courses 6-7 and 18-19). The primary endpoints were event-free survival, overall response, and overall survival. All enrolled patients were included in the primary and safety analyses. The trial is registered with ClinicalTrials.gov, NCT01363128.

FINDINGS

Between Aug 26, 2011, and May 18, 2017, 69 patients (67 patients had B-cell acute lymphoblastic leukaemia and two had B-cell lymphoblastic lymphoma; median age 41 years [IQR 32-50]) were enrolled and treated, including 33 (48%) aged between 18 and 39 years. Nine (27%) of 33 patients had Ph-like acute lymphoblastic leukaemia. With a median follow-up of 44 months (26-53), 4-year event-free survival was 59% (95% CI 48-73); 69% (54-87) in adolescents and young adults aged 18-39 years. 4-year overall survival was 68% (58-81); 74% (60-91) in adolescents and young adults. The overall response rate was 98% (64 of 65 patients). The most common non-haematological grade 3 or 4 adverse events were infections (35 [54%] of 65 patients during induction and 53 [78%] of 68 patients during consolidation). Ten (14%) of 69 patients died in complete remission from sepsis (two [3%]), cardiac arrest (one [1%]), therapy-related acute myeloid leukaemia (two [3%]), and haematopoietic stem-cell transplantation complications (five [7%]). None of these deaths were considered related to ofatumumab treatment by the study investigators.

INTERPRETATION

The combination of hyper-CVAD plus ofatumumab is safe and active in adults with Ph-negative CD20-positive B-cell acute lymphoblastic leukaemia. Modifications of this regimen with the addition of novel monoclonal and bispecific antibody constructs targeting CD19 and CD22 might further improve outcomes and allow reduction in the intensity and duration of chemotherapy.

FUNDING

Novartis.

[CD20 is not a poor prognostic factor for childhood B-lineage acute lymphoblastic leukemia with high white blood cell count]

OBJECTIVE

To study the significance of CD20 combined with white blood cell (WBC) count at diagnosis in the prognosis assessment in children with B-lineage acute lymphoblastic leukemia (ALL).

METHODS

A retrospective analysis was performed on the medical data of 821 B-ALL children who were treated with CCLG-ALL2008 regimen from April 2008 to April 2015. Their survival status was followed up.

RESULTS

Among the 821 children, 547 (66.6%) were negative, while 274 (33.4%) were positive for CD20 expression. Among 694 children with WBC<50×109/L (lower WBC count), the 5-year EFS rates were 65.9%±3.2% and 77.3%±2.0% for CD20 positive and negative patients respectively (P=0.001); the 5-year OS rates were 78.3%±2.9% and 87.5%±1.6% for CD20 positive and negative patients respectively (P=0.005); CD20 positive expression was an independent risk factor for EFS (HR=1.634, P=0.001) and OS (HR=1.761, P=0.005). Among 127 children with WBC>50×109/L (higher WBC count), the 5-year EFS rates was 64.3%±7.7% and 53.7%±5.5% for CD20 positive and negative patients respectively (P=0.135); the 5-year OS rate was 81.4%±6.4% and 58.6%±5.6% for CD20 positive and negative patients respectively (P=0.022); CD20 positive expression was an independent protective factor for OS (HR=0.367, P=0.016).

CONCLUSIONS

In children with B-ALL who are treated with CCLG-ALL2008 regimen, those with CD20 positive expression in lower WBC count at diagnosis have a poor prognosis; however, those with CD20 positive expression in higher WBC count at diagnosis have a better long-time survival.

Impact of Insurance Status on Survival Outcomes in Adults With Acute Lymphoblastic Leukemia (ALL): A Single-center Experience

BACKGROUND

Socioeconomic factors including race, ethnicity, and poverty level have been associated with disparities in survival among adult patients with acute leukemia. Insurance status is also likely to affect survival outcomes in these patients but has not been well studied. We investigated the impact of insurance status at time of diagnosis on survival in adult patients with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Adult patients diagnosed with B-lineage ALL between January 1, 2007 and October 31, 2017 were included, with follow-up through January 19, 2018. Kaplan-Meier survival curves were used to estimate overall survival (OS) and progression-free survival (PFS) for the 2 groups. Cox proportional hazard regression methods were used for univariate and multivariate analyses.

RESULTS

A total of 136 patients were included in the study, 29 without insurance and 107 with insurance at time of diagnosis. Patients without insurance were younger and more likely to be Hispanic or Latino compared with insured patients. When controlling for confounding variables, patients without insurance had worse PFS. There was no statistically significant difference in OS between the 2 groups. Hispanic or Latino ethnicity was associated with improved PFS and OS in multivariate analyses.

CONCLUSIONS

Adult patients with ALL without health insurance at time of diagnosis had worse PFS when controlling for other relevant clinical factors. Lack of insurance may be an obstacle to timely, effective maintenance therapy in the outpatient setting. Further research is needed to understand how insurance status impacts survival and ways to mitigate any disparities.

Outcome of CD20-positive Adult B-cell Acute Lymphoblastic Leukemia and the Impact of Rituximab Therapy

BACKGROUND

In adult B cell precursor acute lymphoblastic leukemia (BCP-ALL), CD20 expression has generally been associated with an adverse prognosis. Incorporating rituximab to standard of care is found to improve the outcome of CD20⁺ BCP-ALL. The aim of this study is to estimate the prognostic effect of CD20 expression and the impact of rituximab in BCP-ALL in Saudi Arabia.

PATIENTS AND METHODS

We performed a retrospective study of 55 Saudi adult patients with BCP-ALL in King Fahad Specialist Hospital in Dammam from 2008 to 2017.

RESULTS

The proportion of CD20⁺ cases was approximately 55%. Excluding rituximab-treated patients, the 5-year overall survival (OS) rate of CD20⁺ patients was lower than CD20^- patients (56% vs. 66%; P = .62). Among CD20⁺ patients, the proportion that received rituximab was approximately 27%. Comparing CD20⁺ patients with and without rituximab, all patients who received rituximab achieved complete remission (CR) 4 weeks post-induction. The 3-year OS rate (88% vs. 63%; P = .35) and the 2-year event-free survival rate (70% vs. 68%; P = .75) were in favor of rituximab. In univariate and multivariate analyses, CR 4 weeks post-induction is recognized as an independent predictor of outcome. However, differences in survival rates did not have a statistical significance.

CONCLUSION

CD20 expression in adult patients with BCP-ALL seems to be higher in Saudi Arabians than in Caucasians, and it seems to have a tendency towards an inferior outcome in terms of OS. Incorporating rituximab to standard of care seems to improve the outcome in terms of CR, OS, and event-free survival.

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia develops in both children and adults, with a peak incidence between 1 year and 4 years. Most acute lymphoblastic leukaemia arises in healthy individuals, and predisposing factors such as inherited genetic susceptibility or environmental exposure have been identified in only a few patients. It is characterised by chromosomal abnormalities and genetic alterations involved in differentiation and proliferation of lymphoid precursor cells. Along with response to treatment, these abnormalities are important prognostic factors. Disease-risk stratification and the development of intensified chemotherapy protocols substantially improves the outcome of patients with acute lymphoblastic leukaemia, particularly in children (1-14 years), but also in adolescents and young adults (15-39 years). However, the outcome of older adults (≥40 years) and patients with relapsed or refractory acute lymphoblastic leukaemia remains poor. New immunotherapeutic strategies, such as monoclonal antibodies and chimeric antigen receptor (CAR) T cells, are being developed and over the next few years could change the options for acute lymphoblastic leukaemia treatment.

CAR T-cells that target acute B-lineage leukemia irrespective of CD19 expression

Chimeric antigen receptor (CAR) T-cells targeting CD19 demonstrate remarkable efficacy in treating B-lineage acute lymphoblastic leukemia (BL-ALL), yet up to 39% of treated patients relapse with CD19(−) disease. We report that CD19(−) escape is associated with downregulation, but preservation, of targetable expression of CD20 and CD22. Accordingly, we reasoned that broadening the spectrum of CD19CAR T-cells to include both CD20 and CD22 would enable them to target CD19(−) escape BL-ALL while preserving their upfront efficacy. We created a CD19/20/22-targeting CAR T-cell by coexpressing individual CAR molecules on a single T-cell using one tricistronic transgene. CD19/20/22CAR T-cells killed CD19(−) blasts from patients who relapsed after CD19CAR T-cell therapy and CRISPR/Cas9 CD19 knockout primary BL-ALL both in vitro and in an animal model, while CD19CAR T-cells were ineffective. At the subcellular level, CD19/20/22CAR T-cells formed dense immune synapses with target cells that mediated effective cytolytic complex formation, were efficient serial killers in single-cell tracking studies, and were as efficacious as CD19CAR T-cells against primary CD19(+) disease. In conclusion, independent of CD19 expression, CD19/20/22CAR T-cells could be used as salvage or front-line CAR therapy for patients with recalcitrant disease.

Recent Advances in the Management of Acute Lymphoblastic Leukaemia

OPINION STATEMENT

The last few years have seen unprecedented advances in treatment options for patients diagnosed with acute lymphoblastic leukaemia (ALL) in adulthood. New targeted drug therapies have been shown in randomised trials to offer significant survival improvements above standard-of-care (SoC) for relapsed disease, whilst being relatively well tolerated. Chimeric antigen receptor T cell therapy (CAR-T) has offered spectacular promise amongst the young adult population, with the possibility of cure for refractory disease. It has reversed the paradigm that transplant is the only curative option at relapse. Data is awaited regarding its effectiveness in the older adult population. Nelarabine represents an advance, but there remains a pressing need to develop new therapies with efficacy against T-ALL, especially in the relapse setting.Outcomes for younger adults have improved with the adoption of paediatric-like regimens, with a focus on dose intensity and heavy use of pegylated asparaginase. Defining who falls into the "young adult" category and would benefit from this approach remains a controversial area. In elderly patients with ALL, the introduction of tyrosine kinase inhibitors (TKIs) and reduction in standard chemotherapy intensity (especially for those with Philadelphia-positive disease) have significantly reduced treatment-associated mortality and resulted in durable remissions with good quality of life.Bone marrow transplantation remains a key therapy in adult ALL, and is still the treatment of choice for relapsed disease. The mortality associated with a myeloablative approach can be substantially lowered by reduced intensity conditioning, without an apparently significant reduction in efficacy.

Clinical-biological characteristics and treatment outcomes of pediatric pro-B ALL patients enrolled in BCH-2003 and CCLG-2008 protocol: a study of 121 Chinese children

Background

Although leukemic blast cells of Pro-B cell acute lymphoblastic leukemia (ALL) are arrested at the same stage of B cell differentiation, the immature B cell subtype is still biologically heterogeneous and is associated with diverse outcomes. This study aimed to explore the clinical-biological characteristics of pediatric pro-B ALL and factors associated with outcomes.

Methods

This study enrolled 121 pediatric patients aged 6 months to 14 years with newly diagnosed CD19⁺CD10⁻ pro-B cell acute lymphoblastic leukemia (pro-B ALL) treated at Beijing Children’s Hospital from March 2003 to October 2018. Genetic abnormalities, immunophenotypic markers, minimal residual disease (MRD) at early treatment stage and long-term outcomes of children treated on two consecutive protocols were analyzed.

Results

KMT2A rearrangements were the most frequent abnormalities (incidence rate 33.06%), and were associated with lower frequency of CD13, CD33, CD22 and CD34 expression and higher frequency of CD7 and NG2 expression. Higher frequency of CD15 and CD133 expression was found in KMT2A-AFF1⁺ patients, exclusively. Presence of CD15 and absence of CD34 at diagnosis correlated with the high burden of MRD at the early stage of treatment. Outcomes were more favorable in patients older than 1 year, with absence of CD20 expression and KMT2A rearrangements, and with MRD lower than 1% at the end of induction and 0.1% before consolidation. Increased intensity of chemotherapy based on MRD analysis did not improve outcomes significantly (5-year EFS 73.9 ± 6.5% for BCH-2003 and 76.1 ± 5.3% for CCLG-2008, P = 0.975). Independent adverse prognostic factors were MRD ≥ 0.1% before consolidation and presence of KMT2A gene rearrangements (odds ratios [ORs] 9.424 [95% confidence interval (CI) 3.210, 27.662; P < 0.001]; 4.142 [1.535, 11.715, P = 0.005]; respectively).

Conclusions

Pediatric pro-B ALL is a heterogeneous disease. Genetic analysis and MRD evaluation can predict patients with dismal prognosis; however, intensive chemotherapy alone does not improve outcomes of these patients and targeted therapy or hematopoietic stem cell transplantation may be required.

Novel monoclonal antibody-based treatment strategies in adults with acute lymphoblastic leukemia

Adult acute lymphoblastic leukemia (ALL) has a poor overall survival compared with pediatric ALL where cure rates are observed in more than 90% of patients. The recent development of novel monoclonal antibodies targeting CD20, CD19, and CD22 has changed the long-term outcome of this disease, both in the frontline setting (e.g. rituximab) and for patients with relapsed/refractory disease (e.g. inotuzumab ozogamicin and blinatumomab). The CD3-CD19 bispecific T-cell-engaging antibody blinatumomab is also the first drug approved in ALL for patients with persistent or recurrent measurable residual disease, providing a new treatment paradigm for these patients. Several new agents are also in development that use novel constructs or target alternative surface epitopes such as CD123, CD25, and CD38. Herein, we review the role of monoclonal antibodies in adult ALL and summarize the current and future approaches in ALL, including novel combination therapies and the possibility of early incorporation of these agents into treatment regimens.

Guidelines Insights: Acute Lymphoblastic Leukemia, Version 1.2019

Survival outcomes for older adults with acute lymphoblastic leukemia (ALL) are poor and optimal management is challenging due to higher-risk leukemia genetics, comorbidities, and lower tolerance to intensive therapy. A critical understanding of these factors guides the selection of frontline therapies and subsequent treatment strategies. In addition, there have been recent developments in minimal/measurable residual disease (MRD) testing and blinatumomab use in the context of MRD-positive disease after therapy. These NCCN Guidelines Insights discuss recent updates to the NCCN Guidelines for ALL regarding upfront therapy in older adults and MRD monitoring/testing in response to ALL treatment.

A pediatric regimen for older adolescents and young adults with acute lymphoblastic leukemia: results of CALGB 10403

Retrospective studies have suggested that older adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) have better survival rates when treated using a pediatric ALL regimen administered by pediatric treatment teams. To address the feasibility and efficacy of using a pediatric treatment regimen for AYA patients with newly diagnosed ALL administered by adult treatment teams, we performed a prospective study, CALGB 10403, with doses and schedule identical to those in the Children's Oncology Group study AALL0232. From 2007 to 2012, 318 patients were enrolled; 295 were eligible and evaluable for response. Median age was 24 years (range, 17-39 years). Use of the pediatric regimen was safe; overall treatment-related mortality was 3%, and there were only 2 postremission deaths. Median event-free survival (EFS) was 78.1 months (95% confidence interval [CI], 41.8 to not reached), more than double the historical control of 30 months (95% CI, 22-38 months); 3-year EFS was 59% (95% CI, 54%-65%). Median overall survival (OS) was not reached. Estimated 3-year OS was 73% (95% CI, 68%-78%). Pretreatment risk factors associated with worse treatment outcomes included obesity and presence of the Philadelphia-like gene expression signature. Use of a pediatric regimen for AYAs with ALL up to age 40 years was feasible and effective, resulting in improved survival rates compared with historical controls. CALGB 10403 can be considered a new treatment standard upon which to build for improving survival for AYAs with ALL. This trial was registered at www.clinicaltrials.gov as #NCT00558519.

Antibody-based therapies in patients with acute lymphoblastic leukemia

The use of multiagent combination chemotherapy regimens results in cure rates of >90% for children and ∼40% for adults with acute lymphoblastic leukemia (ALL) but is associated with extensive toxicity and disappointingly low efficacy in relapsed patients. ALL blast cells express several surface antigens, including CD20, CD22, and CD19, which represent valuable targets for immunotherapy. Monoclonal antibodies, antibody-drug conjugates, and bispecific T-cell-engaging antibodies targeting these antigens offer novel mechanisms of action. Within the last several years, the anti-CD20 antibody rituximab has been added to chemotherapy for newly diagnosed patients <60 years with CD20+ pre-B ALL and significantly improved the 2-year event-free survival from 52% to 65%. In adults with relapsed or refractory CD22+ ALL, the antibody-drug conjugate inotuzumab ozogamicin resulted in a complete response rate of 81% and median overall survival of 7.7 months with reduced toxicity compared with standard chemotherapy. Similarly, the bispecific T-cell-engaging antibody blinatumomab yielded a complete response rate of 44% and a median overall survival of 7.7 months in an extensively treated ALL population. Moreover, ∼80% of ALL patients in complete remission with evidence of minimal residual disease (MRD) achieved a complete MRD response following treatment with blinatumomab. These results highlight the tremendous promise of antibody-based treatment approaches for ALL. Ongoing and future research is critical to further define the role of the various immunotherapies in the frontline treatment of ALL. Additional challenges include the optimal sequencing of the available antibodies in the relapsed setting as well as their integration with stem cell transplant and chimeric antigen receptor T-cell therapy.

Blast Percentage of Bone Marrow Aspirate on Day 14 of Induction Chemotherapy Predicts Adult Acute Lymphoblastic Leukemia Treatment Outcomes

The prognosis of adult acute lymphoblastic leukemia is much worse than that of pediatric acute lymphoblastic leukemia, even when patients achieve complete remission. Early response to treatment can be an important alternative indicator of treatment outcomes. The purpose of our current study was to identify the prognostic value of the blast percentage of the induction interim bone marrow, which might predict relapse-free survival and overall survival in patients with adult acute lymphoblastic leukemia. A retrospective analysis was performed on 80 adult patients diagnosed with Philadelphia chromosome-negative acute lymphoblastic leukemia from 1994 to 2011. Complete remission was observed in 75 (93.8%) patients after induction chemotherapy. On multivariate analysis, a reduction of blasts to a level of 5% or less in the induction interim bone marrow and CD20 positivity were significant prognostic predictors of relapse-free survival (hazard ratio, HR = 2.88, p = 0.006, and HR = 2.67, p = 0.010) and overall survival (HR = 2.10, p = 0.033, and HR = 2.39, p = 0.013). The blast percentage of the induction interim bone marrow may be a useful prognostic factor to predict outcome.

Prognostic Effect of CD20 Expression in Adult B-cell Acute Lymphoblastic Leukemia

INTRODUCTION

The expression of the CD20 on adult B-cell acute lymphoblastic leukemia (ALL-B) has generally been associated with a poor prognosis, and several studies have explored the incorporation of rituximab into the therapeutic regimen for adult ALL-B patients, with a positive effect on event-free survival (EFS).

PATIENTS AND METHODS

We analyzed the prognostic value of CD20 expression and the effect of rituximab for the treatment of Hispanic adult ALL-B patients. We performed a retrospective study of 152 ALL-B patients treated from 2009 to 2016. The patient characteristics and treatment outcomes were analyzed according to CD20 expression (CD20⁺ vs. CD20^-), age group, and treatment with rituximab.

RESULTS

CD20 expression was positive for 47.7% of patients (n = 72). Excluding the patients who had received rituximab, the overall survival (OS) was greater for the CD20^- patient subgroup than for the CD20⁺ subgroup (11.2 vs. 6.9 months; 95% confidence interval [CI], 7.43-14.9; P = .008). In the CD20⁺ subgroup, 10 patients (7.2%) received treatment with rituximab, with 100% reaching complete remission (CR) 4 weeks after treatment. In the 18- to 39-year age group, CD20⁺ patients treated with rituximab had EFS and OS that was not reached. In addition, for CD20⁺ patients who received with chemotherapy, EFS was 3.9 months (95% CI, 0.6-7.2 months; P = .025) and OS was 7.2 months (95% CI, 3.37-11.0; P = .013). Multivariate analysis showed that the use of rituximab was independently associated with OS and CR at 4 weeks after induction.

CONCLUSION

CD20 expression in adult ALL-B is associated with decreased OS. Treatment with rituximab can increase OS, EFS, and CR in the 18- to 39-year age group.

Rituximab in the management of acute lymphoblastic leukemia

INTRODUCTION

The anti-CD20 chimeric monoclonal antibody rituximab has revolutionized the treatment of B-cell malignancies, significantly improving patient clinical outcome. Recently, some single-group studies have suggested that adding rituximab to chemotherapy can improve the outcome of CD20-positive B-cell acute lymphoblastic leukemia (ALL) patients. Areas covered: An overview of the current insights of rituximab in adult ALL patients is presented here. In particular, we focused on results of multicenter randomized phase III trial (GRAALL-2005 - Group for Research on Adult Acute Lymphoblastic Leukemia) that evaluated the benefit of associating rituximab to chemotherapy in Ph-negative, B-lineage ALL expressing the CD20 antigen. Expert opinion: Data from clinical trials confirm that rituximab enhances the efficacy of chemotherapy without additive toxicity in ALL. However, results of GRAAL 2005 study represent only a modest incremental improvement in the treatment of ALL. Other promising compounds as single agent or in combination with chemotherapy are currently in different stages of clinical development. The GRAALL 2005 study sets the stage for other prospective studies which will further elucidate the role of monoclonal antibodies in the management of ALL.

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.

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.

The ABCs of Immunotherapy for Adult Patients With B-Cell Acute Lymphoblastic Leukemia

OBJECTIVE

To review the pharmacology, efficacy, and safety of Food and Drug Administration approved and promising immunotherapy agents used in the treatment of acute lymphoblastic leukemia (ALL).

DATA SOURCES

A literature search was performed of PubMed and MEDLINE databases (1950 to July 2017) and of abstracts from the American Society of Hematology and the American Society of Clinical Oncology. Searches were performed utilizing the following key terms: rituximab, blinatumomab, inotuzumab, ofatumumab, obinutuzumab, Blincyto, Rituxan, Gazyva, Arzerra, CAR T-cell, and chimeric antigen receptor (CAR).

STUDY SELECTION/DATA EXTRACTION

Studies of pharmacology, clinical efficacy, and safety of rituximab, ofatumumab, obinutuzumab, inotuzumab, blinatumomab, and CAR T-cells in the treatment of adult patients with ALL were identified.

DATA SYNTHESIS

Conventional chemotherapy has been the mainstay in the treatment of ALL, producing cure rates of approximately 90% in pediatrics, but it remains suboptimal in adult patients. As such, more effective consolidative modalities and novel therapies for relapsed/refractory disease are needed for adult patients with ALL. In recent years, anti-CD20 antibodies, blinatumomab, inotuzumab, and CD19-targeted CAR T-cells have drastically changed the treatment landscape of B-cell ALL.

CONCLUSION

Outcomes of patients with relapsed disease are improving thanks to new therapies such as blinatumomab, inotuzumab, and CAR T-cells. Although the efficacy of these therapies is impressive, they are not without toxicity, both physical and financial. The optimal sequencing of these therapies still remains a question.

Novel immunotherapies for adult patients with B-lineage acute lymphoblastic leukemia

The past decade witnessed the rapid development of adult B-lineage acute lymphoblastic leukemia (ALL) treatment. Beyond the development of chemotherapy regimens, immunotherapy is starting a new era with unprecedented complete remission (CR) rate. Targeting B-lineage-specific surface markers such as CD19, CD20, CD22, or CD52, immunotherapy has been demonstrating promising clinical results. Among the immunotherapeutic methods, naked monoclonal antibodies (mAbs), antibody-drug conjugate (ADC), bispecific T cell engager (BiTE), and chimeric antigen receptor (CAR) T cells are the main types. In this review, we will examine the emerging preclinical and clinical development on (1) anti-CD20 naked mAbs rituximab, ofatumumab, and obinutuzumab; (2) anti-CD19 ADCs SAR3419 and SGN-CD19A and anti-CD19 BiTE blinatumomab; (3) anti-CD22 naked mAb epratuzumab and anti-CD22 ADC inotuzumab ozogamicin; (4) anti-CD52 naked mAb alemtuzumab; and (5) anti-CD19 CAR T cells. We will discuss their efficacy, adverse effects, as well as future development.

Estimating Long-Term Survival of Adults with Philadelphia Chromosome-Negative Relapsed/Refractory B-Precursor Acute Lymphoblastic Leukemia Treated with Blinatumomab Using Historical Data

Introduction

Blinatumomab is a bispecific T cell-engaging antibody construct indicated for adult patients with relapsed/refractory (R/R) Ph(−) B-precursor acute lymphoblastic leukemia (ALL), an aggressive disease with poor prognosis. A phase 2 single-arm clinical study showed that 43% of patients achieved CR/CRh within two cycles and approximately 20% of patients receiving blinatumomab were still alive after 2 years.

Methods

The objective of the current analysis was to estimate long-term survival of patients receiving blinatumomab beyond the observed time period in the clinical study using a large historical observational dataset. Conditional survival probabilities of blinatumomab-treated patients beyond month 60 were assumed to be the same as the US general population.

Results

At month 60, the estimated proportion of blinatumomab-treated patients alive was more than double that of historical patients (12.6% vs 5.4%). The mean overall survival was 76.1 months for blinatumomab patients and 39.8 months for historical patients. Sensitivity analyses including additional follow-up data from the clinical study showed consistent results.

Conclusions

These findings suggest that blinatumomab provides substantial overall survival benefit to patients with (R/R) Ph(−) B-precursor ALL compared with salvage chemotherapy.

Funding

Amgen.

Trial Registration

ClinicalTrials.gov identifier NCT01466179 and NCT02003612.

Rituximab in B-Lineage Adult Acute Lymphoblastic Leukemia

BACKGROUND

Treatment with rituximab has improved the outcome for patients with non-Hodgkin's lymphoma. Patients with B-lineage acute lymphoblastic leukemia (ALL) may also have the CD20 antigen, which is targeted by rituximab. Although single-group studies suggest that adding rituximab to chemotherapy could improve the outcome in such patients, this hypothesis has not been tested in a randomized trial.

METHODS

We randomly assigned adults (18 to 59 years of age) with CD20-positive, Philadelphia chromosome (Ph)-negative ALL to receive chemotherapy with or without rituximab, with event-free survival as the primary end point. Rituximab was given during all treatment phases, for a total of 16 to 18 infusions.

RESULTS

From May 2006 through April 2014, a total of 209 patients were enrolled: 105 in the rituximab group and 104 in the control group. After a median follow-up of 30 months, event-free survival was longer in the rituximab group than in the control group (hazard ratio, 0.66; 95% confidence interval [CI], 0.45 to 0.98; P=0.04); the estimated 2-year event-free survival rates were 65% (95% CI, 56 to 75) and 52% (95% CI, 43 to 63), respectively. Treatment with rituximab remained associated with longer event-free survival in a multivariate analysis. The overall incidence rate of severe adverse events did not differ significantly between the two groups, but fewer allergic reactions to asparaginase were observed in the rituximab group.

CONCLUSIONS

Adding rituximab to the ALL chemotherapy protocol improved the outcome for younger adults with CD20-positive, Ph-negative ALL. (Funded by the Regional Clinical Research Office, Paris, and others; ClinicalTrials.gov number, NCT00327678 .).

Correlation between deletion of the CDKN2 gene and tyrosine kinase inhibitor resistance in adult Philadelphia chromosome-positive acute lymphoblastic leukemia

BACKGROUND

Frequency relapses are common in Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) following tyrosine kinase inhibitors (TKIs). CDKN2A/B is believed to contribute to this chemotherapy resistance.

METHODS

To further investigate the association between CDKN2 status and TKI resistance, the prevalence of CDKN2 deletions and its correlation with a variety of clinical features was assessed in 135 Ph-positive ALL patients using interphase fluorescence in situ hybridization (I-FISH).

RESULTS

Results showed that no difference occurred between patients with CDKN2 deletion (44/135) and wild-type patients in sex, age, and complete remission (CR) rate following induction chemotherapy combined with tyrosine kinase inhibitors (TKIs). However, CDKN2 deletion carriers demonstrated higher white blood cell (WBC) count, enhanced rates of hepatosplenomegaly (P = 0.006), and upregulation of CD20 expression (P = 0.001). Moreover, deletions of CDKN2 resulted in lower rates of complete molecular response (undetectable BCR/ABL), increased cumulative incidence of relapse, short overall survival (OS), and disease-free survival (DFS) time (P < 0.05) even though these patients received chemotherapy plus TKIs followed by allogenic hematopoietic stem cell transplantation (Allo-HSCT). In the case of 44 patients who presented with CDKN2 deletion, 18 patients were treated with dasatinib treatment, and another 26 patients were treated with imatinib therapy, and our study found that there were no differences associated with OS (P = 0.508) and DFS (P = 0.555) between the two groups.

CONCLUSIONS

CDKN2 deletion is frequently acquired during Ph-positive ALL progression and serves as a poor prognostic marker of long-term outcome in Ph-positive ALL patients with CDKN2 deletion even after the second-generation tyrosine kinase inhibitor treatment.

Immunophenotypic markers in adult acute lymphoblastic leukemia: the prognostic significance of CD20 and TdT expression

BACKGROUND

Efforts to overcome poor outcomes in patients with adult acute lymphoblastic leukemia (ALL) have focused on combining new therapeutic agents targeting immunophenotypic markers (IPMs) with classical cytotoxic agents; therefore, it is important to evaluate the clinical significance of IPMs.

METHODS

Baseline characteristics and clinical outcomes of patients with adult ALL were retrospectively analyzed. The percentage of blasts expressing IPMs at diagnosis was measured by multicolor flow cytometry analysis. Samples in which ≥20% of blasts expressed an IPM were considered positive.

RESULTS

Among the total patient population (N=230), almost all (92%) were in first or second hematological complete remission (HCR) and 54% received allogeneic hematopoietic cell transplant (allo-HCT). Five-year hematologic relapse-free survival (HRFS) and overall survival (OS) rates were 36% and 39%, respectively, and 45.6% and 80.5% of patients were positive for the IPMs CD20 and terminal deoxynucleotidyl transferase (TdT), respectively. Expression of CD20, CD13, CD34, and TdT was associated with HRFS rate, and expression of CD20 and CD13 was associated with OS rate, as was the performance of allo-HCT. In multivariate analysis, positivity for CD20 (HRFS: hazard ratio [HR], 2.21, P<0.001; OS: HR, 1.63, P=0.015) and negativity for TdT (HRFS: HR, 2.30, P=0.001) were both significantly associated with outcomes. When patients were categorized into three subgroups according to positivity for CD20 and TdT, there were significant differences in HRFS and OS among the subgroups.

CONCLUSION

Positivity for CD20 and TdT expression and clinical risk group were prognostic factors in adult ALL.

Clinical updates in adult acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a clonal disease characterized by B or T lineage. Here we cover the clinical manifestations, pathophysiology and therapy for ALL. Additionally, we will discuss the evidence for minimal residual disease assessment, novel molecular targets and newly developed targeted therapies. The separation of ALL into Philadelphia chromosome positive and recently into Philadelphia-like disease represents the most exciting developments in this disease. Finally, the advent of new immunotherapeutic approaches led us to predict that in few years, ALL therapy might be based heavily on non-chemotherapeutic approaches.

Outcome of B-Cell Acute Lymphoblastic Leukemia in Brazilian Children: Immunophenotypical, Hematological, and Clinical Evaluation

The aim of this study is to investigate the clinical, hematological, and immunophenotypic characteristics of Brazilian children with B-cell acute lymphoblastic leukemia (B-ALL) to identify prognostic biomarkers of the disease. Thirty-three children newly diagnosed with B-ALL were followed between March 2004 and December 2009. Information about the demographic profile, diagnosis, immunophenotype, clinical manifestations, and disease outcome were gathered from the patients' medical records. Of the 33 patients with B-ALL, 18 were male and 15 female. Eighteen patients were classified as high risk; 13 as low risk, and 2 as true low risk. The frequencies of cluster of differentiation (CD)10, CD19, and CD20 antigens were 69.7%, 81.8%, and 18.2%, respectively. Six patients (18.2%) had aberrant expression of myeloid antigens. At diagnosis, patients immunopositive for CD20 had elevated white blood cell counts (P = 0.018) and lower platelet counts (P = 0.017). The 6-year overall survival was 67.5%± 3.47%. Our results demonstrate the distinct immunophenotypic and prognostic characteristics of patients with B-ALL, which can be related to the Brazilian racial admixture. Consequently, these results will most likely aid in the selection of additional prognostic markers and their use in monitoring the clinical manifestations and treatment response among B-ALL patients.

CD20 and Outcome of Childhood Precursor B-cell Acute Lymphoblastic Leukemia: A Meta-analysis

CD20 is a B-cell differentiation antigen that is expressed variably in precursor B-cell acute lymphoblastic leukemia (BCP-ALL). The prognostic significance of CD20 expression in childhood BCP-ALL remains controversial. Some studies have demonstrated that CD20 overexpression correlates with worse survival in pediatric patients with BCP-ALL, but some other studies suggest a better outcome. To explore the prognostic role of high CD20 expression in pediatric BCP-ALL, we performed a meta-analysis of the previous studies that provided survival information according to CD20 expression status. Pooled hazard ratios (HRs) indicated that high CD20 expression had no inferior impact on the prognosis of pediatric BCP-ALL. The summary HR for overall survival was 0.70 and combined HR for event-free survival was 1.01. These findings suggest that high CD20 expression does not influence the outcome for pediatric BCP-ALL. CD20 may lack prognostic value in children with BCP-ALL.

[Clinical features and survival analysis of patients with CD20 positive adult B-lineage acute lymphoblastic leukemia]

OBJECTIVE

To explore the clinical and survival significance of CD20 positive adult patients with B-lineage acute lymphoblastic leukemia (B-ALL).

METHODS

The clinical features and survival of 168 adult patients with B-ALL diagnosed and treated in our department from May 2007 to July 2011 were analyzed retrospectively, 58 expressed CD20 and 110 not.

RESULTS

The sex, distribution of age, anemia, thrombocytopenia, infiltration of liver, spleen and lymph nodes, the expression of myeloid lineage marker, incidence of Ph chromosome, complete remission within 4 weeks showed no significant differences in CD20 positive and negative groups (P>0.05); median white blood cell count at diagnosis and the rate of patients with high white blood cell count in CD20 positive group were 19.2×10⁹/L and 37.9% respectively, which were significantly higher than those of 6.93 × 10⁹/L and 20.9% in CD20 negative group (P<0.05); cumulative incidence of relapse between two groups showed significant difference (P<0.05); multivariable analysis for overall survival and progress-free survival identified CD20 positivity as independent predictor.

CONCLUSION

The expression of CD20 in adult patients with B-ALL appeared to be associated with high white blood cell count and poor prognosis.