Outcome of treatment after first relapse in adults with acute lymphoblastic leukemia initially treated by the LALA-94 trial

The clinical efficacy of a daratumumab-based regimen in relapsed/refractory acute leukemia: a single-center experience

Relapsed/refractory acute leukemia (R/R-AL) is associated with a low remission rate, short survival rate, and poor prognosis. Treating R/R-AL remains challenging as there is no standardized effective regimen; hence, there is a need for efficient therapies. CD38 expression has been observed in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Daratumumab is a humanized anti-CD38 monoclonal antibody used to treat multiple myeloma and has been reported to treat R/R-AL safely and effectively. The clinical data of 10 adult patients with R/R-AL who were treated with a daratumumab-based salvage regimen between July 2018 and May 2023 at our center were analyzed retrospectively. Seven AML and three ALL cases were included in the analysis. Seven (70%) patients showed responses to the treatments (complete response [CR], 60%; partial response [PR], 10%). Of the seven responders, three underwent allogenic stem cell transplantation (ASCT), including one who underwent a second ASCT. Among the five patients with R/R AML who had prior exposure to venetoclax, three achieved a therapeutic response (two CR and one PR) when re-treated with venetoclax in combination with daratumumab. The median follow-up time was 6.15 months (0.9-21 months). Overall survival and event-free survival rates at 12 months were 68.6% and 40.0%, respectively. The main adverse events included grade 3 febrile neutropenia (20%) and grade 3 hematological toxicities (60%). The daratumumab-based salvage regimen offers patients with R/R-AL the opportunity of remission with acceptable tolerability, creating the possibility of bridging ASCT.

Flotetuzumab as a salvage immunotherapy in advanced CD123-positive hematological malignancies, a phase 1 pilot study

CD123 "expression" is common in hematological malignancies, including acute lymphoblastic leukemia (ALL). Flotetuzumab is a novel, investigational CD3/CD123 DART®. We conducted a phase 1 study evaluating safety and efficacy of flotetuzumab in relapsed/refractory ALL (Cohort A) and other advanced CD123-positive hematological malignancies (excluding myeloid malignancies) (cohort B). Thirteen patients (9 in Cohort A and 4 in Cohort B) were treated at dose level 1 (500 ng/kg/day) before early closure due to discontinuation of drug development by sponsor. Two dose limiting toxicities (Grade 4 thrombocytopenia and neutropenia) occurred in one patient in Cohort B. Cytokine release syndrome occurred in most patients (85%), all being grade ≤2. Responses only occurred in Cohort B, with a partial response in one patient with Hodgkin's lymphoma and morphological complete remission in the bone marrow in one patient with blastic plasmacytoid dendritic cell neoplasm. In conclusion, flotetuzumab had a manageable safety profile in advanced CD123-positive hematological malignancies.

Management of ALL in adults: 2024 ELN recommendations from a European expert panel

ABSTRACT

Experts from the European Leukemia Net (ELN) working group for adult acute lymphoblastic leukemia have identified an unmet need for guidance regarding management of adult acute lymphoblastic leukemia (ALL) from diagnosis to aftercare. The group has previously summarized their recommendations regarding diagnostic approaches, prognostic factors, and assessment of ALL. The current recommendation summarizes clinical management. It covers treatment approaches, including the use of new immunotherapies, application of minimal residual disease for treatment decisions, management of specific subgroups, and challenging treatment situations as well as late effects and supportive care. The recommendation provides guidance for physicians caring for adult patients with ALL which has to be complemented by regional expertise preferably provided by national academic study groups.

Nelarabine: when and how to use in the treatment of T-cell acute lymphoblastic leukemia

ABSTRACT

T-cell acute lymphoblastic leukemia or lymphoblastic lymphoma (T-ALL/LBL) is a rare hematologic malignancy most commonly affecting adolescent and young adult males. Outcomes are dismal for patients who relapse, thus, improvement in treatment is needed. Nelarabine, a prodrug of the deoxyguanosine analog 9-β-arabinofuranosylguanine, is uniquely toxic to T lymphoblasts, compared with B lymphoblasts and normal lymphocytes, and has been developed for the treatment of T-ALL/LBL. Based on phase 1 and 2 trials in children and adults, single-agent nelarabine is approved for treatment of patients with relapsed or refractory T-ALL/LBL, with the major adverse effect being central and peripheral neurotoxicity. Since its approval in 2005, nelarabine has been studied in combination with other chemotherapy agents for relapsed disease and is also being studied as a component of initial treatment in pediatric and adult patients. Here, we review current data on nelarabine and present our approach to the use of nelarabine in the treatment of patients with T-ALL/LBL.

Diagnostic and therapeutic advances in adults with acute lymphoblastic leukemia in the era of gene analysis and targeted immunotherapy

Acute lymphoblastic leukemia (ALL) is one of the most rapidly changing hematological malignancies with advanced understanding of the genetic landscape, detection methods of minimal residual disease (MRD), and the development of immunotherapeutic agents with good clinical outcomes. The annual incidence of adult ALL in Korea is 300-350 patients per year. The WHO classification of ALL was revised in 2022 to reflect the molecular cytogenetic features and suggest new adverse- risk subgroups, such as Ph-like ALL and ETP-ALL. We continue to use traditional adverse-risk features and cytogenetics, with MRD-directed post-remission therapy including allogeneic hematopoietic cell transplantation. However, with the introduction of novel agents, such as ponatinib, blinatumomab, and inotuzumab ozogamicin incorporated into frontline therapy, good MRD responses have been achieved, and overall survival outcomes are improving. Accordingly, some clinical trials have suggested a possible era of chemotherapy-free or transplantation-free approaches in the near future. Nevertheless, relapse of refractory ALL still occurs, and some poor ALL subtypes, such as Ph-like ALL and ETP-ALL, are unsolved problems for which novel agents and treatment strategies are needed. In this review, we summarize the currently applied diagnostic and therapeutic practices in the era of advanced genetic analysis and targeted immunotherapies in United States and Europe and introduce real-world Korean data.

A pilot study of implication of machine learning for relapse prediction after allogeneic stem cell transplantation in adults with Ph-positive acute lymphoblastic leukemia

The posttransplant relapse in Ph-positive ALL increases the risk of death. There is an unmet need for instruments to predict the risk of relapse and plan prophylaxis. In this study, we analyzed posttransplant data by machine learning algorithms. Seventy-four Ph-positive ALL patients with a median age of 30 (range 18-55) years who previously underwent allo-HSCT, were retrospectively enrolled. Ninety-three percent of patients received prophylactic/preemptive TKIs after allo-HSCT. The values of the BCR::ABL1 level at serial assessments and over variables were collected in specified intervals after allo-HSCT. They were used to model relapse risk with several machine-learning approaches. GBM proved superior to the other algorithms and provided a maximal AUC score of 0.91. BCR::ABL1 level before and after allo-HSCT, prediction moment, and chronic GvHD had the highest value in the model. It was shown that after Day + 100, both error rates do not exceed 22%, while before D + 100, the model fails to make accurate predictions. As a result, we determined BCR::ABL1 levels at which the relapse risk remains low. Thus, the current BCR::ABL1 level less than 0.06% in patients with chronic GvHD predicts low risk of relapse. At the same time, patients without chronic GVHD after allo-HSCT should be classified as high risk with any level of BCR::ABL1. GBM model with posttransplant laboratory values of BCR::ABL1 provides a high prediction of relapse after allo-HSCT in the era of TKIs prophylaxis. Validation of this approach is warranted.

Novel precision medicine approaches and treatment strategies in hematological malignancies

Genetic testing has been applied for decades in clinical routine diagnostics of hematological malignancies to improve disease (sub)classification, prognostication, patient management, and survival. In recent classifications of hematological malignancies, disease subtypes are defined by key recurrent genetic alterations detected by conventional methods (i.e., cytogenetics, fluorescence in situ hybridization, and targeted sequencing). Hematological malignancies were also one of the first disease areas in which targeted therapies were introduced, the prime example being BCR::ABL1 inhibitors, followed by an increasing number of targeted inhibitors hitting the Achilles' heel of each disease, resulting in a clear patient benefit. Owing to the technical advances in high-throughput sequencing, we can now apply broad genomic tests, including comprehensive gene panels or whole-genome and whole-transcriptome sequencing, to identify clinically important diagnostic, prognostic, and predictive markers. In this review, we give examples of how precision diagnostics has been implemented to guide treatment selection and improve survival in myeloid (myelodysplastic syndromes and acute myeloid leukemia) and lymphoid malignancies (acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and chronic lymphocytic leukemia). We discuss the relevance and potential of monitoring measurable residual disease using ultra-sensitive techniques to assess therapy response and detect early relapses. Finally, we bring up the promising avenue of functional precision medicine, combining ex vivo drug screening with various omics technologies, to provide novel treatment options for patients with advanced disease. Although we are only in the beginning of the field of precision hematology, we foresee rapid development with new types of diagnostics and treatment strategies becoming available to the benefit of our patients.

General condition and comorbidity of long-term survivors of adult acute lymphoblastic leukemia

Cure rates in adult acute lymphoblastic leukemia (ALL) improved using pediatric-based chemotherapy and stem cell transplantation (SCT). However, limited data on the health condition of cured adults are available whereas pediatric data cannot be transferred. The GMALL analyzed the health status in survivors of adult ALL retrospectively. Physicians answered a questionnaire on general condition (Eastern Cooperative Oncology Group [ECOG] status) and comorbidity or syndrome occurrence observed after treatment. Five hundred and thirty-eight patients with a median age of 29 (range, 15-64) years at diagnosis were analyzed, median follow-up was 7 (range, 3-24) years. Thirty-one percent had received SCT. ECOG status was 0-1 in 94%, 34% had not developed significant comorbidities. Most frequent comorbidities involved the neurologic system (27%), endocrine system (20%), skin (18%), graft-versus-host-disease (15%), cardiac system (13%), fatigue (13%). SCT impacted ECOG status and comorbidity occurrence significantly. ECOG 0-1 was observed in 86% of SCT and 98% of non-SCT patients (P<0.0001); comorbidity was observed in 87% and 57% respectively (P<0.0001). Our analysis elucidates the spectrum of comorbidities in cured adult ALL patients, with higher risk for transplanted patients, providing stimulations for the design of adequate aftercare programs. Overall, a large proportion of non-SCT patients achieved unrestricted general condition. The data provide a reference for new patient-centered endpoints in future trials.

Long-term follow-up of donor-derived CD7 CAR T-cell therapy in patients with T-cell acute lymphoblastic leukemia

BACKGROUND

Donor-derived CD7-directed chimeric antigen receptor (CAR) T cells showed feasibility and early efficacy in patients with refractory or relapsed T-cell acute lymphoblastic leukemia (r/r T-ALL), in a previous phase I trial report, at a median follow-up of 6.3 months. Here we report long-term safety and activity of the therapy after a 2-year follow-up.

METHODS

Participants received CD7-directed CAR T cells derived from prior stem cell transplantation (SCT) donors or from HLA-matched new donors after lymphodepletion. The target dose was 1 × 10⁶ (± 30%) CAR T cells per kg of patient weight. The primary endpoint was safety with efficacy secondary. This report focuses on the long-term follow-up and discusses them in the context of previously reported early outcomes.

RESULTS

Twenty participants were enrolled and received infusion with CD7 CAR T cells. After a median follow-up time of 27.0 (range, 24.0-29.3) months, the overall response rate and complete response rate were 95% (19/20 patients) and 85% (17/20 patients), respectively, and 35% (7/20) of patients proceeded to SCT. Six patients experienced disease relapse with a median time-to-relapse of 6 (range, 4.0-10.9) months, and 4 of these 6 patients were found to have lost CD7 expression on tumor cells. Progression-free survival (PFS) and overall survival (OS) rates 24 months after treatment were respectively 36.8% (95% CI, 13.8-59.8%) and 42.3% (95% CI, 18.8-65.8%), with median PFS and OS of respectively 11.0 (95% CI, 6.7-12.5) months and 18.3 (95% CI, 12.5-20.8) months. Previously reported short-term adverse events (< 30 days after treatment) included grade 3-4 cytokine release syndrome (CRS; 10%) and grade 1-2 graft-versus-host disease (GVHD; 60%). Serious adverse events reported > 30 days after treatment included five infections and one grade 4 intestinal GVHD. Despite good CD7 CAR T-cell persistence, non-CAR T and natural killer cells were predominantly CD7-negative and eventually returned to normal levels in about half of the participants.

CONCLUSIONS

In this 2-year follow-up analysis, donor-derived CD7 CAR T-cell treatment demonstrated durable efficacy in a subset of patients with r/r T-ALL. Disease relapse was the main cause of treatment failure, and severe infection was a noteworthy late-onset adverse event.

TRIAL REGISTRATION

ChiCTR2000034762.

The evolution of acute lymphoblastic leukemia research and therapy at MD Anderson over four decades

Progress in the research and therapy of adult acute lymphoblastic leukemia (ALL) is accelerating. This analysis summarizes the data derived from the clinical trials conducted at MD Anderson between 1985 and 2022 across ALL subtypes. In Philadelphia chromosome-positive ALL, the addition of BCR::ABL1 tyrosine kinase inhibitors (TKIs) to intensive chemotherapy since 2000, improved outcomes. More recently, a chemotherapy-free regimen with blinatumomab and ponatinib resulted in a complete molecular remission rate of 85% and an estimated 3-year survival rate of 90%, potentially reducing the role of, and need for allogeneic stem cell transplantation (SCT) in remission. In younger patients with pre-B Philadelphia chromosome-negative ALL, the integration of blinatumomab and inotuzumab into the frontline therapy has improved the estimated 3-year survival rate to 85% across all risk categories. Our future strategy is to evaluate the early integration of both immunotherapy agents, inotuzumab and blinatumomab, with low-dose chemotherapy (dose-dense mini-Hyper-CVD-inotuzumab-blinatumomab) into the frontline setting followed by CAR T cells consolidation in high-risk patients, without any further maintenance therapy. In older patients, using less intensive chemotherapy (mini-Hyper-CVD) in combination with inotuzumab and blinatumomab has improved the 5-year survival rate to 50%. Among patients ≥ 65-70 years, the mortality in complete remission (CR) is still high and is multifactorial (old age, death in CR with infections, development of myelodysplastic syndrome or acute myeloid leukemia). A chemotherapy-free regimen with inotuzumab and blinatumomab is being investigated. The assessment of measurable residual disease (MRD) by next-generation sequencing (NGS) is superior to conventional assays, with early MRD negativity by NGS being associated with the best survival. We anticipate that the future therapy in B-ALL will involve less intensive and shorter chemotherapy regimens in combination with agents targeting CD19 (blinatumomab), CD20, and CD22 (inotuzumab). The optimal timing and use of CAR T cells therapy may be in the setting of minimal disease, and future trials will assess the role of CAR T cells as a consolidation among high-risk patients to replace allogeneic SCT. In summary, the management of ALL has witnessed significant progress during the past four decades. Novel combination regimens including newer-generation BCR::ABL1 TKIs and novel antibodies are questioning the need and duration of intensive chemotherapy and allogeneic SCT.

Comparing the efficacy of salvage regimens for relapsed/refractory B-cell acute lymphoblastic leukaemia: a systematic review and network meta-analysis

The complete remission (CR) rate and overall survival (OS) of relapsed/refractory (R/R) B-cell acute lymphoblastic leukaemia (B-ALL) are not satisfactory. The available salvage regimens include standard chemotherapy, inotuzumab ozogamicin, blinatumomab and cluster of differentiation (CD)19 chimeric antigen receptor T cells (CAR T), and the NCCN guidelines recommend all of these therapies with no preference. Dual CD19/CD22 CAR T-cells have emerged as new treatments and have shown some efficacy, with high CR rates and preventing CD19-negative relapse. However, direct comparisons of the CR rate and long-term survival among the different salvage therapies are lacking. Databases including PubMed, Embase, Web of Science and Cochrane were searched from inception to January 31, 2022, for relevant studies. The outcomes of interest were complete remission/complete remission with incomplete haematologic recovery (CR/CRi) rates and 1-year overall survival (OS) rates. Odds ratios (ORs) were generated for binary outcomes, and the mean difference (MD) was generated for consecutive outcomes by network meta-analysis. CD19 CAR T-cells demonstrated a significantly better effect in improving the CR/CRi rate than blinatumomab (OR = 8.32, 95% CI: 1.18 to 58.44) and chemotherapy (OR = 16.4, 95% CI: 2.76 to 97.45). In terms of OS, CD19 CAR T-cells and dual CD19/CD22 CAR T-cells both had a higher 1-year OS rate than blinatumomab, inotuzumab ozogamicin and chemotherapy. There was no significant difference between CD19 CAR T-cells and dual CD19/CD22 CAR T-cells in terms of 1-year OS and CR/CRi rates. CD19 CAR T-cells are effective in inducing CR, and CD19 CAR T-cells and dual CD19/CD22 CAR T-cells show benefits for overall survival. More high-quality randomized controlled trials and longer follow-ups are needed to confirm and update the results of this analysis in the future.

Management of B-cell lineage acute lymphoblastic leukemia: expert opinion from an Indian panel via Delphi consensus method

Introduction

Currently, there are no guidelines for the management of B-cell lineage acute lymphoblastic leukemia (B-ALL) from an Indian perspective. The diagnostic workup, monitoring, and treatment of B-ALL vary among different physicians and institutes.

Objective

To develop evidence-based practical consensus recommendations for the management of B-ALL in Indian settings.

Methods

Modified Delphi consensus methodology was considered to arrive at a consensus. An expert scientific committee of 15 experts from India constituted the panel. Clinically relevant questions belonging to three major domains were drafted for presentation and discussion: (i) diagnosis and risk assignment; (ii) frontline treatment; and (iii) choice of therapy (optimal vs. real-world practice) in relapsed/refractory (R/R) settings. The questionnaire was shared with the panel members through an online survey platform. The level of consensus was categorized into high (≥ 80%), moderate (60%-79%), and no consensus (< 60%). The process involved 2 rounds of discussion and 3 rounds of Delphi survey. The questions that received near or no consensus were discussed during virtual meetings (Delphi rounds 1 and 2). The final draft of the consensus was emailed to the panel for final review.

Results

Experts recommended morphologic assessment of peripheral blood or bone marrow, flow cytometric immunophenotyping, and conventional cytogenetic analysis in the initial diagnostic workup. Berlin-Frankfurt-Münster (BFM)-based protocol is the preferred frontline therapy in pediatric and adolescent and young adult patients with B-ALL. BFM/German Multicenter Study Group for Adult Acute Lymphoblastic Leukemia-based regimen is suggested in adult patients with B-ALL. Immunotherapy (blinatumomab or inotuzumab ozogamicin) followed by allogeneic hematopoietic cell transplantation (allo-HCT) is the optimal choice of therapy that would yield the best outcomes if offered in the first salvage in patients with R/R B-ALL. In patients with financial constraints or prior allo-HCT (real-world practice) at first relapse, standard-intensive chemotherapy followed by allo-HCT may be considered. For subsequent relapses, chimeric antigen receptor T-cell therapy or palliative care was suggested as the optimal choice of therapy.

Conclusion

This expert consensus will offer guidance to oncologists/clinicians on the management of B-ALL in Indian settings.

TSLP as a Potential Therapy in the Treatment of CRLF2 B Cell Acute Lymphoblastic Leukemia

Cytokine receptor-like factor 2 B-cell acute lymphoblastic leukemia (CRLF2 B-ALL) is a high-risk subtype characterized by CRLF2 overexpression with poor survival rates in children and adults. CRLF2 and interleukin-7 receptor alpha (IL-7Rα) form a receptor for the cytokine thymic stromal lymphopoietin (TSLP), which induces JAK/STAT and PI3K/AKT/mTOR pathway signals. Previous studies from our group showed that low TSLP doses increased STAT5, AKT, and S6 phosphorylation and contributed to CRLF2 B-ALL cell survival. Here we investigated the role of TSLP in the survival and proliferation of CRLF2 B-ALL cells in vitro and in vivo. We hypothesized that high doses of TSLP increase CRLF2 signals and contribute to increased proliferation of CRLF2 B-ALL cells in vitro and in vivo. Interestingly, we observed the opposite effect. Specifically, high doses of TSLP induced apoptosis in human CRLF2 B-ALL cell lines in vitro, prevented engraftment of CRLF2 B-ALL cells, and prolonged the survival of +TSLP patient-derived-xenograft mice. Mechanistically, we showed that high doses of TSLP induced loss of its receptor and loss of CRLF2 signals in vitro. These results suggest that high doses of TSLP could be further investigated as a potential therapy for the treatment of CRLF2 B-ALL.

Comparable outcomes in patients with B-cell acute lymphoblastic leukemia receiving haploidentical hematopoietic stem cell transplantation: Pretransplant minimal residual disease-negative complete remission following chimeric antigen receptor T-cell therapy versus chemotherapy

Introduction

Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy followed by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) markedly improves the long-term survival of patients with refractory/relapsed (R/R) B-cell acute lymphoblastic leukemia (B-ALL).

Methods

We performed a parallel comparison of transplant outcomes in 168 B-ALL patients undergoing haplo-HSCT after achieving minimal residual disease (MRD)-negative complete remission (CR) from CAR-T therapy (n = 28) or chemotherapy (n = 140) between January 2016 and August 2021. We further divided the chemotherapy group into the first CR group (chemo+CR1, n = 118) and a second or more CR group (chemo+≥CR2, n = 22).

Results

With a median follow-up period of 31.0 months, the 2-year overall survival (OS), leukemia-free survival (LFS), non-relapse mortality (NRM), and relapse rates in the CAR-T and chemotherapy groups did not differ significantly (OS, 87.9% vs. 71.5 %; LFS, 72.0% vs. 66.8%; NRM, 3.9% vs. 13.7%; relapse, 24.1% vs. 19.4%). Multivariate analysis confirmed that ≥CR2 at transplantation following chemotherapy was an independent risk factor associated with poor OS (hazard ratio (HR) 4.22 [95% CI, 1.34–13.293], p = 0.014) and LFS (HR 2.57 [95% CI, 1.041–6.343], p = 0.041). The probabilities of OS and LFS at 2 years in the CAR-T group were comparable to those in the chemo+CR1 group but significantly higher than those in the chemo+≥CR2 group (OS, 87.9% vs. 37.8%, p = 0.007; LFS, 72.0% vs. 41.7%, p = 0.043). No significant differences in the incidences of NRM were noted among the three groups.

Conclusions

Our results demonstrated that patients with R/R B-ALL receiving haplo-HSCT after CAR-T therapy achieved comparable outcomes to patients transplanted post-chemotherapy-based MRD-negative CR1, without increased risk of transplant-related mortality and toxicity.

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.

Allogeneic Hematopoietic Stem Cell Transplantation for Adult Philadelphia Chromosome-Negative B-Cell Acute Lymphoblastic Leukemia in Second Complete Remission

Even in the era of high-intensity chemotherapy, disease recurrence remains a major cause of treatment failure in adult patients with Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia (Ph-negative B-ALL). For patients who achieved second complete remission (CR2) with salvage chemotherapy, allogeneic hematopoietic stem cell transplantation (allo-HSCT) could be the best curative treatment. However, limited data are available on the outcomes of allo-HSCT for adult Ph-negative B-ALL in CR2 in the high-intensity chemotherapy era. We evaluated the transplantation outcomes of adult patients with Ph-negative B-ALL in CR2 compared with those in CR1. We also clarified the prognostic factors among adult allo-HSCT recipients with Ph-negative B-ALL in CR2. We conducted a nationwide retrospective study using the data form Japanese transplant registry database. Patients aged ≥16 years and underwent their first allo-HSCT between 2003 and 2017 were included. The 3-year overall survival (OS) rate of the patients in CR2 (n = 382) was significantly lower than that in first complete remission (n = 1375) (51.8% versus 68.1%; P < .001), accompanied by a higher relapse rate (34.2% versus 17.6% at 3 years; P < .001). In a multivariate analysis among CR2 patients, time from diagnosis to allo-HSCT (≤2 years) was a significant factor for OS (hazard ratio [HR] 1.87; P < .001) and relapse (HR = 1.88; P < .001), whereas age at allo-HSCT (≥30 years) was a significant factor for OS (HR = 2.10, P < .001) and nonrelapse mortality (HR = 2.68; P < .001). By assigning a score of 1 to each factor, the 3-year OS rate of CR2 patients significantly stratified: 70.7% in patients with score 0, 56.4% with score 1, and 28.4% with score 2 (P < .001). The survival outcomes of allo-HSCT in adult Ph-negative B-ALL patients in CR2 were inferior to those in CR1 in the high-intensity chemotherapy era, mainly because of the higher relapse rate. Among the CR2 patients, the short time between diagnosis and allo-HSCT was a significant risk factor for disease recurrence and overall mortality. Better disease control with novel treatment strategies may be needed for early relapse. In addition, the nonrelapse mortality rate in patients over 30 years of age was particularly high among CR2 patients, suggesting the need for improved supportive care for these patients. Further studies are warranted on the outcomes of allo-HSCT after achieving CR2 with novel drugs, such as inotuzumab ozogamicin and blinatumomab.

Real-World Multicenter Experience in Tumor Debulking Prior to Blinatumomab Administration in Adult Patients With Relapsed/Refractory B-Cell Precursor Acute Lymphoblastic Leukemia

Blinatumomab is an immunotherapeutic agent with dual specificity for CD3 and CD19 that is approved for the treatment of relapsed/refractory B-cell precursor acute lymphoblastic leukemia (R/R B-ALL). A steroid based pre-treatment is recommended before administering blinatumomab to patients with a high tumor burden to minimize the risk of tumor lysis syndrome, but the optimal debulking regimen and whether it can improve responses remain unclear. The present study retrospectively evaluated real-world outcomes following tumor debulking and blinatumomab infusion in R/R B-ALL adult patients treated at 7 Italian centers. Data were collected from 34 patients. The choice of the cytoreductive therapy was made by the treating clinician on an individual patient basis; regimens included chemotherapy (n=23), steroids (n=7) and tyrosine kinase inhibitors alone or in combination (n=4). The rate of complete responses (CR) and complete minimal residual disease (MRD) responses in CR patients were 67.6% and 81% respectively, after 2 cycles of blinatumomab. Moreover, among patients with a high tumor burden 50% obtained a CR, with 89% of them also achieving a complete MRD response. Favorable responses were also obtained in patients over 50 years of age at treatment initiation. Overall, 7 of 23 patients in CR after blinatumomab underwent hematopoietic stem cell transplantation. The results of this retrospective study highlight the heterogeneity in the use of pre-blinatumomab tumor debulking in real-life clinical practice. Nonetheless, debulking pre-treatment enhanced responses to blinatumomab compared to historic studies, indicating that this strategy may help to improve outcomes for R/R B-ALL patients.

Cost-Effectiveness of Inotuzumab Ozogamicin Compared to Standard of Care Chemotherapy for Treating Relapsed or Refractory Acute Lymphoblastic Leukaemia Patients in Norway and Sweden

OBJECTIVE

The aim was to estimate the cost-effectiveness of inotuzumab ozogamicin (InO) versus standard of care chemotherapy (SoC) for adults with relapsed or refractory B cell acute lymphoblastic leukaemia (R/R ALL) in Sweden and Norway, and compare this to evaluations made by the health technology assessment (HTA) authorities Tandvårds- och läkemedelsförmånsverket (TLV) and the Norwegian Medicines Agency (NoMA).

MATERIALS AND METHODS

A partitioned survival model was developed to determine incremental cost-effectiveness ratios (ICERs) for InO versus SoC. Parametric survival models were fit to overall survival and progression-free survival Kaplan-Meier data from the INO-VATE ALL phase III trial. Two base cases were run using (1) Swedish and (2) Norwegian inputs (costs and discount rates). Core clinical inputs and utilities did not differ between countries. Analyses were then conducted to reflect the preferred assumptions of TLV and NoMA. Univariate and multivariate sensitivity analyses were performed.

RESULTS

The base case deterministic ICERs for InO versus SoC were €16,219/quality-adjusted life years (QALY) in Sweden (probabilistic €19,415) and €44,405/QALY in Norway (probabilistic €47,305). The ICERs using our model but applying the preferred assumptions of TLV or NoMA were €74,061/QALY (probabilistic €77,484) and €59,391/QALY (probabilistic €63,632), respectively. Differences between our base cases and the ICERs with TLV and NoMA settings were mainly explained by the exclusion of productivity costs and use of pooled post-haematopoietic stem-cell transplant (post-HSCT) survival in Sweden and use of higher HSCT costs in Norway. All ICERs remained below the approximated willingness-to-pay thresholds. The probability of InO being cost-effective ranged from 77 to 99% versus SoC.

CONCLUSIONS

InO can likely be considered cost-effective versus SoC under our and the HTA-preferred settings.

Keeping up with venetoclax for leukemic malignancies: key findings, optimal regimens and clinical considerations

INTRODUCTION

Venetoclax has transformed the treatment landscape in hematologic malignancies, especially in elderly population. With high rates of remission, deep and durable responses, and safe toxicity profile, venetoclax in combination therapy has been extremely effective, garnering accelerated approval and becoming standard of care in lymphoid and myeloid malignancies.

AREAS COVERED

The role of venetoclax in the intrinsic apoptotic pathway is covered. This includes preclinical and clinical experience of venetoclax monotherapy and combination therapy in relapsed/refractory and frontline CLL, AML, ALL and high-risk MDS, with an emphasis on key clinical trials and efficacy of combination regimens in distinct mutational landscapes. Strategies to mitigate myelosuppression, manage dose adjustments and infectious complications are addressed.

EXPERT OPINION

Targeting BCL-2 offers a safe and highly effective adjunct to available therapies in hematologic malignancies. Despite success and frequent utilization of venetoclax, several resistance mechanisms have been elucidated, prompting development of novel combinatorial strategies. Further, on-target myelosuppression of venetoclax is a key obstacle in clinical practice, requiring diligent monitoring and practice-based knowledge of dose modifications. Despite these limitations, venetoclax has gained tremendous popularity in hematologic-oncology, becoming an integral component of numerous combination regimes, with ongoing plethora of clinical trials encompassing standard chemotherapy, targeted agents and immune-based approaches.

Clinical experience of CAR T cells for B cell acute lymphoblastic leukemia

Chimeric antigen receptor (CAR) T cell therapy has transformed the treatment for both pediatric and adult patients with relapsed or refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL). Clinical trial results across multiple institutions with different CAR constructs report significant response rates in treated patients. One product (tisagenlecleucel) is currently FDA approved for the treatment of R/R B-ALL in patients <26 y/o. Successful application of this therapy is limited by high relapse rates, potential for significant toxicity, and logistical issues surrounding collection/production. Herein, we review published data on the use of CAR T cells for B-ALL, including results from early pivotal clinical trials, relapse data, incidence of toxicity, and mechanisms to optimize CAR T cell therapy.

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.

Acute Lymphoblastic Leukemia and Acute Lymphoblastic Lymphoma: Same Disease Spectrum but Two Distinct Diagnoses

PURPOSE OF REVIEW

Rare malignancies developing from lymphocyte precursor cells, lymphoblastic leukemia (LBL), and acute lymphoblastic lymphoma (ALL) have historically been viewed as different manifestations of the same disease process. This review examines data on their epidemiology, genetics, clinical presentation, and response to treatment while highlighting areas of similarity and divergence between these two clinical entities.

RECENT FINDINGS

Pediatric-type ALL chemotherapy regimens, compared to both lymphoma-type chemotherapy and adult-type ALL regimens, have led to improved outcomes for children, adolescents, and young adults with ALL. BCR-ABL-targeting tyrosine kinase inhibitors (TKIs) have improved outcomes in Philadelphia chromosome-positive (Ph +) ALL and in rare cases of Ph + LBL. Newer therapies including blinatumomab, inotuzumab, CAR-T therapy, and nelarabine have improved outcomes in selected cases of ALL and have an emerging role in the management of LBL. Better understanding of ALL and LBL biology allows for the development of therapies that target immunophenotypic or genetic features found in subsets of both diseases. Novel therapies are leading to improved outcomes in Ph + and relapsed and refractory disease.

KTE-X19 for relapsed or refractory adult B-cell acute lymphoblastic leukaemia: phase 2 results of the single-arm, open-label, multicentre ZUMA-3 study

BACKGROUND

Despite treatment with novel therapies and allogeneic stem-cell transplant (allo-SCT) consolidation, outcomes in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia remain poor, underlining the need for more effective therapies.

METHODS

We report the pivotal phase 2 results of ZUMA-3, an international, multicentre, single-arm, open-label study evaluating the efficacy and safety of the autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy KTE-X19 in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia. Patients were enrolled at 25 sites in the USA, Canada, and Europe. Eligible patients were aged 18 years or older, with Eastern Cooperative Oncology Group performance status of 0-1, and morphological disease in the bone marrow (>5% blasts). After leukapheresis and conditioning chemotherapy, patients received a single KTE-X19 infusion (1 × 106 CAR T cells per kg bodyweight). The primary endpoint was the rate of overall complete remission or complete remission with incomplete haematological recovery by central assessment. Duration of remission and relapse-free survival, overall survival, minimal residual disease (MRD) negativity rate, and allo-SCT rate were assessed as secondary endpoints. Efficacy and safety analyses were done in the treated population (all patients who received a dose of KTE-X19). This study is registered with ClinicalTrials.gov, NCT02614066.

FINDINGS

Between Oct 1, 2018, and Oct 9, 2019, 71 patients were enrolled and underwent leukapheresis. KTE-X19 was successfully manufactured for 65 (92%) patients and administered to 55 (77%). The median age of treated patients was 40 years (IQR 28-52). At the median follow-up of 16·4 months (13·8-19·6), 39 patients (71%; 95% CI 57-82, p<0·0001) had complete remission or complete remission with incomplete haematological recovery, with 31 (56%) patients reaching complete remission. Median duration of remission was 12·8 months (95% CI 8·7-not estimable), median relapse-free survival was 11·6 months (2·7-15·5), and median overall survival was 18·2 months (15·9-not estimable). Among responders, the median overall survival was not reached, and 38 (97%) patients had MRD negativity. Ten (18%) patients received allo-SCT consolidation after KTE-X19 infusion. The most common adverse events of grade 3 or higher were anaemia (27 [49%] patients) and pyrexia (20 [36%] patients). 14 (25%) patients had infections of grade 3 or higher. Two grade 5 KTE-X19-related events occurred (brain herniation and septic shock). Cytokine release syndrome of grade 3 or higher occurred in 13 (24%) patients and neurological events of grade 3 or higher occurred in 14 (25%) patients.

INTERPRETATION

KTE-X19 showed a high rate of complete remission or complete remission with incomplete haematological recovery in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia, with the median overall survival not reached in responding patients, and a manageable safety profile. These findings indicate that KTE-X19 has the potential to confer long-term clinical benefit to these patients.

FUNDING

Kite, a Gilead Company.

Inotuzumab Ozogamicin Monotherapy as an Outpatient Salvage Treatment in Relapsed Refractory B-Cell Acute Lymphoblastic Leukemia: Compassionate Access

Relapsed and refractory (RR) acute lymphoblastic leukemia (ALL) poses unique and difficult challenges to a practicing clinician in India where access to novel immunotherapies is limited. Between 2017 and 2020, eight patients with B-cell ALL at our center received inotuzumab ozogamicin (IO) monotherapy on compassionate access, as salvage therapy after at least two lines of conventional therapy failure, and most often as outpatient infusion. Eight patients (21–60 years, three females) received IO. Three patients had morphologic relapse and five patients reported persistent measurable residual disease (MRD). The best response on IO therapy achieved was negative MRD in six of seven patients and complete response (CR) with persistent MRD in one. One patient died (intracranial hemorrhage) before completion of first cycle. All responding patients were transplant eligible and four patients (57%) underwent allogeneic hematopoietic cell transplantation (Allo-HCT). Median follow-up of this cohort is 9 months (4–29.6 months), four patients (57%) are alive as stable with negative MRD. No significant infusion reactions occurred during therapy. Three patients developed grades III and IV neutropenia, two patients showed grade III transaminitis, and two patients developed post-HCT severe sinusoidal obstruction syndrome (SOS). IO is a feasible outpatient based salvage therapy to improve the remission status in RR B-cell ALL.

Residual disease is a strong prognostic marker in patients with acute lymphoblastic leukaemia with chemotherapy-refractory or relapsed disease prior to allogeneic stem cell transplantation

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is one of the curative treatment options for acute lymphoblastic leukaemia (ALL). However, the outcomes in patients transplanted without complete remission (non-CR) have not yet been fully reported, and detailed analyses are required to identify subgroups in which optimal prognosis is expected and to optimize pre-transplant therapeutic strategies. Hence, we performed a multicentred retrospective cohort study including a total of 663 adult ALL patients transplanted at non-CR status; the median bone marrow (BM) blast counts at HSCT was 13·2%, and 203 patients (30·6%) were treated at primary induction failure status. The overall survival (OS) was 31·1% at two years, and the multivariate analyses identified five prognostic risk factors, including older age (≥50 years), increased BM blasts (≥10%), poor performance status, high haematopoietic cell transplantation (HCT)-comorbidity index, and relapsed disease status, among which BM blast was the most significantly related. A predictive scoring system composed of these risk factors clearly stratified OS (15·6-59·5% at two years). In conclusion, this is the first large-scale study to analyze the correlation of patient characteristics with post-transplant prognosis in ALL transplanted at non-CR status. The importance of blast control before HSCT should be focused on for better patient prognosis.

Real-world outcomes of adult B-cell acute lymphocytic leukemia patients treated with blinatumomab

The availability and use of blinatumomab symbolizes a paradigm shift in the management of B-cell acute lymphoblastic leukemia (ALL). We conducted a retrospective multicenter cohort analysis of 239 ALL patients (227 relapsed refractory [RR], n = 227; minimal residual disease [MRD], n = 12) who received blinatumomab outside of clinical trials to evaluate safety and efficacy in the "real-world" setting. The median age of patients at blinatumomab initiation was 48 years (range, 18-85). Sixty-one (26%) patients had ≥3 prior therapies and 46 (19%) had allogeneic hematopoietic cell transplantation before blinatumomab. The response rate (complete remission/complete remission with incomplete count recovery) in patients with RR disease was 65% (47% MRD-). Among 12 patients who received blinatumomab for MRD, 9 (75%) patients achieved MRD negativity. In patients with RR disease, median relapse-free survival and overall survival (OS) after blinatumomab was 32 months and 12.7 months, respectively. Among patients who received blinatumomab for MRD, median relapse-free survival was not reached (54% MRD- at 2 years) and OS was 34.7 months. Grade ≥3 cytokine release syndrome, neurotoxicity, and hepatotoxicity were observed in 3%, 7%, and 10% of patients, respectively. Among patients who achieved complete remission/complete remission with incomplete count recovery, consolidation therapy with allogeneic hematopoietic cell transplantation retained favorable prognostic significance for OS (hazard ratio, 0.54; 95% confidence interval, 0.30-0.97; P = .04). In this largest "real-world" experience published to date, blinatumomab demonstrated responses comparable to those reported in clinical trials. The optimal sequencing of newer therapies in ALL requires further study.

STAT5: From Pathogenesis Mechanism to Therapeutic Approach in Acute Leukemia

BACKGROUND

Based on the results of multiple studies, multiple signaling pathways is a major cause of resistence to chemotherapy in leukemia cells. Signal transducer and activator of transcription 5 (STAT5) is among these factors; it plays an essential role in proliferation of leukemic cells.

METHODS

We obtained the materials used in our study via PubMed search from 1996 through 2019. The key search terms included "STAT5," "acute leukemia," "leukemogenesis," and "mutation."

RESULTS

On activation, STAT5 not only inhibits apoptosis of leukemic cells via activating the B-cell lymphoma 2 (BCL-2) gene but also inhibits resistance to chemotherapy by enhancing human telomerase reverse transcriptase (hTERT) expression and maintaining telomere length in cells. It has also been shown that a number of mutations in the STAT5 gene and in related genes alter the expression of STAT5.

CONCLUSION

The identification of STAT5 and the factors activated in its up- or downstream expression, affecting its function, contribute to better treatments such as targeted therapy rather than chemotherapy, improving the quality of life patients.

Blinatumomab-induced T cell activation at single cell transcriptome resolution

Background

Bi-specific T-cell engager (BiTE) antibody is a class of bispecific antibodies designed for cancer immunotherapy. Blinatumomab is the first approved BiTE to treat acute B cell lymphoblastic leukemia (B-ALL). It brings killer T and target B cells into close proximity, activating patient’s autologous T cells to kill malignant B cells via mechanisms such as cytolytic immune synapse formation and inflammatory cytokine production. However, the activated T-cell subtypes and the target cell-dependent T cell responses induced by blinatumomab, as well as the mechanisms of resistance to blinatumomab therapy are largely unknown.

Results

In this study, we performed single-cell sequencing analysis to identify transcriptional changes in T cells following blinatumomab-induced T cell activation using single cells from both, a human cell line model and a patient-derived model of blinatumomab-mediated cytotoxicity. In total, the transcriptome of 17,920 single T cells from the cell line model and 2271 single T cells from patient samples were analyzed. We found that CD8+ effector memory T cells, CD4+ central memory T cells, naïve T cells, and regulatory T cells were activated after blinatumomab treatment. Here, blinatumomab-induced transcriptional changes reflected the functional immune activity of the blinatumomab-activated T cells, including the upregulation of pathways such as the immune system, glycolysis, IFNA signaling, gap junctions, and IFNG signaling. Co-stimulatory (TNFRSF4 and TNFRSF18) and co-inhibitory (LAG3) receptors were similarly upregulated in blinatumomab-activated T cells, indicating ligand-dependent T cell functions. Particularly, B-ALL cell expression of TNFSF4, which encodes the ligand of T cell co-stimulatory receptor TNFRSF4, was found positively correlated with the response to blinatumomab treatment. Furthermore, recombinant human TNFSF4 protein enhanced the cytotoxic activity of blinatumomab against B-ALL cells.

Conclusion

These results reveal a target cell-dependent mechanism of T-cell activation by blinatumomab and suggest that TNFSF4 may be responsible for the resistant mechanism and a potential target for combination therapy with blinatumomab, to treat B-ALL or other B-cell malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07435-2.

A Review of Clinical Outcomes of CAR T-Cell Therapies for B-Acute Lymphoblastic Leukemia

Introduction: Treatment of relapsed and refractory (R/R) B acute lymphoblastic leukemia (B-ALL) represents an unmet medical need in children and adults. Adoptive T cells engineered to express a chimeric antigen receptor (CAR-T) is emerging as an effective technique for treating these patients. Areas covered: Efficacy and safety of CAR-T therapy in R/R B-ALL patients. Expert opinion: CD19 CAR-T infusion induce high CR rates in patients with poor prognosis and few therapeutic options, while real-life data demonstrate similar results with an interestingly lower incidence of grade 3/4 toxicity. Nevertheless, despite impressive in-depth responses, more than half of patients will experience a relapse. Therefore, rather than using CAR-T cell therapy as a stand-alone option, consolidation with allogeneic stem-cell transplant (Allo-SCT) after CAR-T treatment might increase long-term outcome. Moreover, CD19 is one target, but several other targets are being examined, such as CD20 and CD22 and dual-targeting CARs or combination therapy. Another issue is the time consuming process of CAR-T engineering. New platforms have shortened the CAR-T cell manufacturing process, and studies are underway to evaluate the effectiveness. Another way to mitigate waiting is the development of allogeneic “off the shelf” therapy. In conclusion, CD19-targeted CAR-modified T-cell therapy has shown unprecedented results in patients without curative options. Future work focusing on target identification, toxicity management and reducing manufacturing time will broaden the clinical applicability and bring this exciting therapy to more patients, with longer-term remissions without additional Allo-SCT.

Clonal evolution detected with conventional cytogenetic analysis is a potent prognostic factor in adult patients with relapsed Philadelphia chromosome-negative acute lymphoblastic leukemia

Additional cytogenetic abnormality (ACA) acquisition at relapse has been recognized as clonal evolution at the cytogenetic level, and has a significant prognostic impact on relapsed acute myeloid leukemia (AML) patients. We retrospectively investigated 48 relapsed Philadelphia chromosome (Ph)-negative acute lymphoblastic leukemia (ALL) patients to clarify the clinical significance of ACA acquisition at the first relapse. Twenty-seven patients (56 %) acquired ACA at the first relapse. No significant predisposing factor for ACA acquisition was identified. Notably, patients with ACA acquisition showed a significantly lower second complete remission rate compared to those without ACA acquisition (14.8 % vs. 76.2 %, respectively; p < 0.01), and furthermore, the overall survival rates after the first relapse were significantly different between patients with and without ACA acquisition (25.9 % vs. 55.3 % at 1 year, respectively; p < 0.01). Multivariate analysis extracted ACA acquisition as the only negative prognostic factor (hazard ratio: 2.55, p < 0.01). All seven patients with ACA acquisition who underwent allogeneic transplant died within 2 years after relapse. These findings suggested that clonal evolution detected with conventional cytogenetic analysis at the first relapse triggers severe chemo-refractoriness in Ph-negative ALL cells, just like AML cells. Novel therapeutic strategies are warranted for this subset of patients.

Allogeneic Hematopoietic Cell Transplantation for Relapsed and Refractory Philadelphia Negative B Cell ALL in the Era of Novel Salvage Therapies

Introduction of novel salvage therapies and expansion of the donor pool within the past decade have allowed more patients with relapsed/refractory (r/r) B cell acute lymphoblastic leukemia (B-ALL) to receive allogeneic hematopoietic cell transplantation (alloHCT). The impact of each salvage therapy on transplant outcomes have not been compared. Our primary objective was to determine post-HCT relapse-free survival (RFS) in adult patients with r/r Philadelphia-chromosome negative (Ph^neg) B-ALL. We retrospectively studied alloHCT outcomes in 108 adult patients with r/r Ph^neg B-ALL transplanted in morphological remission achieved by salvage therapy. Salvage therapies were chemotherapy-based combination (n = 45, 42%), blinatumomab (n=43, 40%), inotuzumab (n = 14, 13%), or CAR T cells (n = 6, 6%). The 2-year RFS and overall survival (OS) were 44% and 50%, respectively. In multivariable analysis, conditioning with reduced-intensity or non-myeloablative regimens (hazard ratio [HR] = 2.23, 95% confidence interval [CI], 1.31-3.80; P = .003), having received ≥3 lines of therapies prior to transplant (HR = 2.66, 95% CI, 1.56-4.54; P < .001), and inotuzumab (HR = 2.42, 95% CI, 1.14-5.12; Wald P value = .021) were independently associated with lower RFS. Blinatumomab (HR = 1.10, 95% CI, 0.62-1.96) had comparable RFS to chemotherapy. Incidence of hepatic sinusoidal syndrome was highest with inotuzumab (P < .001); however, 30-day mortality and intensive care unit admissions were not different per salvage therapy. The alloHCT in r/r Ph^neg B-ALL after remission induction with blinatumomab or chemotherapy led to encouraging outcomes if morphologic CR was achieved. In contrast, pretransplantation inotuzumab therapy was associated with inferior RFS. Larger studies are warranted to confirm our observations. Early transplantation after relapse and the utilization of myeloablative conditioning, when feasible, were key factors associated with improved outcomes after alloHCT in these patients.

Role of blinatumomab, inotuzumab, and CAR T-cells: Which to choose and how to sequence for patients with relapsed disease

Recent approval of several novel agents has dramatically improved outcomes for patients with relapsed and refractory (R/R) B-cell acute lymphoblastic leukemia. Blinatumomab, a bi-specific T-cell engager targeted to CD3 and CD19, inotuzumab ozogamicin (InO), an antibody-drug conjugate to CD22, and tisagenlecleucel, a CD19 chimeric antigen receptor T-cell with a 4-1BB costimulatory domain, have all demonstrated impressive response rates in R/R B-ALL as compared to historic controls. However, important considerations when choosing among these novel agents include clinical features that may impact efficacy, such as relative disease burden, antigen expression, and T-cell function, as well as patient and disease characteristics that may contribute to risk of toxicity. In addition, suitability of the patient for hematopoietic stem cell transplant (HSCT) as well as patient preference must also be considered. This review will focus on factors to weigh when choosing an agent in the setting of R/R disease and important challenges moving forward.

Antibody based therapy in relapsed acute lymphoblastic leukemia

Outcomes for relapsed and refractory acute lymphoblastic leukemia (ALL) remain poor. With the advent of targeted monoclonal antibodies and antibody constructs, these outcomes have been significantly improved both in the frontline and salvage setting. These targets include a bispecific antibody that targets both CD3 and CD19, known as blinatumomab, as well as a conjugated antibody that targets CD22, known as inotuzumab ozogamicin. These agents have been thoroughly studied and successively approved for use as monotherapy, however, more recently they have been incorporated in combination or sequentially with cytotoxic chemotherapy. In this chapter, we will discuss the role that these monoclonal antibodies play as monotherapy and in combination in the treatment of ALL in the salvage setting, and how they continue to transform the treatment management of relapsed and refractory ALL.

Long-term survival of patients with relapsed/refractory acute lymphoblastic leukemia treated with blinatumomab

Background

Blinatumomab is a CD19 BiTE (bispecific T‐cell engager) immuno‐oncology therapy that mediates the lysis of cells expressing CD19.

Methods

A pooled analysis of long‐term follow‐up data from 2 phase 2 studies that evaluated blinatumomab in heavily pretreated adults with Philadelphia chromosome–negative, relapsed/refractory B‐cell precursor acute lymphoblastic leukemia was conducted.

Results

A total of 259 patients were included in the analysis. The median overall survival (OS) among all patients, regardless of response, was 7.5 months (95% confidence interval [CI], 5.5‐8.5 months); the median follow‐up time for OS was 36.0 months (range, 0.3‐60.8 months). The median relapse‐free survival (RFS) among patients who achieved a complete remission (CR) or complete remission with partial hematologic recovery (CRh) in the first 2 cycles (n = 123) was 7.7 months (95% CI, 6.2‐10.0 months); the median follow‐up time for RFS was 35.0 months (range, 9.5‐59.5 months). OS and RFS plateaued with 3‐year rates of 17.7% and 23.4%, respectively. The cumulative incidence function of the time to relapse, with death not due to relapse considered a competing risk, for patients who achieved a CR/CRh within 2 cycles of treatment also plateaued with a 3‐year relapse rate of 59.3%. For patients who achieved a CR/CRh with blinatumomab followed by allogeneic hematopoietic stem cell transplantation while in continuous CR, the median OS was 18.1 months (95% CI, 10.3‐30.0 months) with a 3‐year survival rate of 37.2%.

Conclusions

These data suggest that long‐term survival is possible after blinatumomab therapy.

Lay Summary

Immuno‐oncology therapies such as blinatumomab activate the patient's own immune system to kill cancer cells.

This study combined follow‐up data from 2 blinatumomab‐related clinical trials to evaluate long‐term survival in patients with relapsed and/or refractory B‐cell precursor acute lymphoblastic leukemia at high risk for unfavorable outcomes.

Among patients who achieved a deep response with blinatumomab, one‐third lived 3 years or longer. These findings suggest that long‐term survival is possible after treatment with blinatumomab.

Patients achieving remission after blinatumomab can have a durable response. The survival plateau indicates a high probability of a cure in those patients responding to blinatumomab and alive after 3 years.

Prognostic factors for survival after allogeneic transplantation in acute lymphoblastic leukemia

Allogeneic stem cell transplantation (allo-SCT) offers a curative option in adult patients with acute lymphoblastic leukemia (ALL). Prognostic factors for survival after allo-SCT have not been sufficiently defined: pheno-/genotype, patients´ age, conditioning regimens and remission at allo-SCT are under discussion. We analyzed the outcome of 180 consecutive adult ALL-patients undergoing allo-SCT at our center between 1995 and 2018 to identify specific prognostic factors. In our cohort 19% were older than 55 years, 28% had Philadelphia-positive B-ALL, 24% T-ALL. 54% were transplanted in first complete remission (CR1), 13% in CR2 after salvage therapy, 31% reached no remission (8% within first-line, 23% within salvage therapy). In 66% conditioning contained total body irradiation (TBI). With a median follow-up of 10 years, we observed an overall survival of 33% at 10 years, and a progression free survival of 31%. The cumulative incidence of relapse was 41% at 10 years, the cumulative incidence of non-relapse mortality 28%. Acute graft-versus-host disease (GvHD) II°-IV° occurred in 31%, moderate/severe chronic GvHD in 27%. Survival was better in patients reaching CR before allo-SCT and in those receiving TBI. No difference between patients younger/older than 55 years and between different phenotypes was observed. Survival after allo-SCT improved considerably over the last decades.

Treatment and outcome of Philadelphia chromosome-positive acute lymphoblastic leukemia in adults after relapse

INTRODUCTION

Despite the significant progress that has been made over the last years in the front-line treatment of Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL), relapses are frequent and their treatment remains a challenge, especially among patients with resistant BCR-ABL1 mutations.

AREAS COVERED

This manuscript reviews available data for the treatment of adult patients with relapsed/refractory Ph-positive ALL, with a focus on the role of tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and immunotherapy.

EXPERT OPINION

Although a majority of patients with first relapsed Ph-positive ALL respond to subsequent salvage chemotherapy plus TKI combination, their outcomes remain poor. The main predictor of survival is the achievement of major molecular response anytime during the morphological response. More treatment strategies to improve survival are under investigation. Monoclonal antibodies and bispecific antibody constructs hold considerable promise in improving the outcomes of patients with relapsed ALL including Ph-positive ALL.

CART19-BE-01: A Multicenter Trial of ARI-0001 Cell Therapy in Patients with CD19+ Relapsed/Refractory Malignancies

We evaluated the administration of ARI-0001 cells (chimeric antigen receptor T cells targeting CD19) in adult and pediatric patients with relapsed/refractory CD19⁺ malignancies. Patients received cyclophosphamide and fludarabine followed by ARI-0001 cells at a dose of 0.4-5 × 10⁶ ARI-0001 cells/kg, initially as a single dose and later split into 3 fractions (10%, 30%, and 60%) with full administration depending on the absence of cytokine release syndrome (CRS). 58 patients were included, of which 47 received therapy: 38 with acute lymphoblastic leukemia (ALL), 8 with non-Hodgkin's lymphoma, and 1 with chronic lymphocytic leukemia. In patients with ALL, grade ≥3 CRS was observed in 13.2% (26.7% before versus 4.3% after the amendment), grade ≥3 neurotoxicity was observed in 2.6%, and the procedure-related mortality was 7.9% at day +100, with no procedure-related deaths after the amendment. The measurable residual disease-negative complete response rate was 71.1% at day +100. Progression-free survival was 47% (95% IC 27%-67%) at 1 year: 51.3% before versus 39.5% after the amendment. Overall survival was 68.6% (95% IC 49.2%-88%) at 1 year. In conclusion, the administration of ARI-0001 cells provided safety and efficacy results that are comparable with other academic or commercially available products. This trial was registered as ClinicalTrials.gov: NCT03144583.

Cost-utility analysis of inotuzumab ozogamicin for relapsed or refractory B cell acute lymphoblastic leukemia from the perspective of Taiwan's health care system

OBJECTIVES

We conduct a cost-utility analysis of inotuzumab ozogamicin (INO) versus chemotherapy as the standard of care (SOC) for adults with relapsed or refractory B cell acute lymphoblastic leukemia.

METHODS

A Markov model incorporating transition probabilities between health states was applied to simulate disease progression. The model inputs, including overall survival, progression-free survival, and utility parameters, were obtained from the INO-VATE ALL trial and literatures. The Taiwan Cancer Registry Database and the Health and Welfare Database were utilized to identify the patient cohort and medical costs from the perspective of National Health Insurance Administration. The lifetime medical costs (in 2017 US dollars), quality-adjusted life years (QALYs) gained, and associated incremental cost-effectiveness ratio (ICER) were the main study outcomes.

RESULTS

The lifetime medical costs for INO and SOC were $176,795 and $69,496, and the QALYs gained were 2.25 and 0.84, respectively. The ICER for INO versus SOC was $76,044 per QALY gained, which is slightly more than three times Taiwan's gross domestic product per capita (i.e., $73,224). Favorable economic results for INO versus SOC were found with an increased time horizon for model simulation, less discounting for the future benefit, and higher stem cell transplantation (SCT) rate after INO treatment; and among patients aged less than 55 years, with no SCT history, or in the first salvage treatment.

CONCLUSIONS

INO versus SOC has higher costs but is more effective. The use of INO is favorable for patients in the early treatment course and when more future benefit associated with INO is considered.

Molecular response with blinatumomab in relapsed/refractory B-cell precursor acute lymphoblastic leukemia

Minimal residual disease (MRD), where leukemic cell levels are lower than the morphologic detection threshold, is the most important prognostic factor for acute lymphoblastic leukemia (ALL) relapse during first-line chemotherapy treatment and is standard of care in treatment monitoring and decision making. Limited data are available on the prognostic value of MRD response after relapse. We evaluated the relationship between MRD response and outcomes in blinatumomab-treated adults with relapsed/refractory (R/R) B-cell precursor ALL. Of 90 patients with complete remission (CR) or CR with partial hematologic recovery (CRh), 64 (71.1%) achieved a complete MRD response (no detectable individual rearrangements of immunoglobulin/T-cell receptor genes by polymerase chain reaction [PCR] at a minimum sensitivity level of 10-4). Eleven patients had MRD <10-4. Therefore, overall, 75 (83.3%) experienced an MRD response (no detectable MRD or detectable MRD) measured by PCR within the first 2 treatment cycles. Overall survival (OS) and relapse-free survival (RFS) were significantly longer in patients who achieved CR/CRh and MRD response (median, 20.6 and 9.0 months, respectively) compared with CR/CRh patients without MRD response (median, 12.5 and 2.3 months, respectively). In conclusion, longer durations of OS and RFS associated with MRD response support the value of achieving MRD response and its use as a prognostic factor for blinatumomab treatment in R/R ALL. This trial was registered at www.clinicaltrials.gov as #NCT01466179.

Inotuzumab ozogamicin for relapsed/refractory acute lymphoblastic leukemia: outcomes by disease burden

Adults with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) have a poor prognosis, especially if disease burden is high. This post hoc analysis of the phase 3 INO-VATE trial examined the efficacy and safety of inotuzumab ozogamicin (InO) vs. standard of care chemotherapy (SC) among R/R ALL patients with low, moderate, or high disease burden, respectively, defined as bone marrow blasts (BMB) < 50% (n = 53 vs. 48), 50–90% (n = 79 vs. 83), and >90% (n = 30 vs. 30). Patients in the InO vs. SC arm with low, moderate, and high BMB%, respectively, had improved rates of complete remission/complete remission with incomplete hematologic recovery (74% vs. 46% [p = 0.0022], 75 vs. 27% [p < 0.0001], and 70 vs. 17% [p < 0.0001]), and improved overall survival (hazard ratio: 0.64 [p = 0.0260], 0.81 [p = 0.1109], and 0.60 [p = 0.0335]). Irrespective of BMB%, cytopenias were the most common treatment-emergent adverse events, and post-transplant veno-occlusive disease was more common with InO vs. SC. Patients with extramedullary disease or lymphoblastic lymphoma showed similar efficacy and safety outcomes. This favorable benefit-to-risk ratio of InO treatment irrespective of disease burden supports its use in challenging and high disease burden subpopulations. INO-VATE is registered at www.clinicaltrials.gov: #NCT01564784.

Acute lymphoblastic leukemia (ALL for short) is a type of blood cancer where the body makes too many immature white blood cells called lymphoblasts. This study involved people with ALL whose cancer had returned after, or stopped responding to, previous treatment. These people received either inotuzumab ozogamicin (InO for short) or standard chemotherapy. Researchers divided people into groups, based on the level of lymphoblast cells they had in their bone marrow (called disease burden): low, medium, or high disease burden. In this study, compared with people who received standard chemotherapy, people who received InO were more likely to have no signs of their cancer (called remission), live to the end of the study, and/or reach the end of the study without their cancer getting worse. The researchers saw these results across all disease burden groups. For people who received InO, those with high disease burden were equally as likely as those with low disease burden to achieve remission, and/or experience medical problems. For people who received standard chemotherapy, those with high disease burden were less likely than those with low disease burden to achieve remission. Further information in a plain language format is available in Supplementary Information (SI) Fig. S1.

Current treatment strategies for Philadelphia chromosome-positive adult acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is an aggressive hematological disease. The incorporation of tyrosine kinase inhibitors (TKIs) into the standard treatment regimen for Philadelphia (Ph)-positive ALL significantly improved clinical outcomes. TKI-based induction chemotherapy, followed by allogeneic hematopoietic cell transplantation (HCT) during the first complete remission (CR), is the standard of care for ALL patients. However, treatment with TKIs alone or TKIs plus low-intensity chemotherapy can achieve CR in some patients. Although this strategy is not enough to induce a deeper molecular response, it can reduce the incidence of treatment-related mortality. Despite promising results from pediatric trials, allogeneic HCT remains an important component of the treatment strategy for Ph-positive adult ALL. However, improving the highly sensitive BCR-ABL1 assays and introducing immunotherapy may decrease the demand for allogeneic HCT. Nevertheless, the treatment of Ph-positive ALL is still challenging, especially in cases with relapsed and refractory disease. Potent TKIs and monoclonal antibodies, such as blinatumomab and inotuzumab, have improved patient outcomes in relapse and refractory cases of ALL. The introduction of effective agents, such as potent TKIs and monoclonal antibodies, may improve the possibility of remission in Ph-positive ALL patients and hopefully cure this disease.

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.

Bispecific T-cell engaging antibodies in B-cell precursor acute lymphoblastic leukemias: focus on blinatumomab

Bispecific T-cell engaging antibodies are constructs engineered to bind to two different antigens, one to a tumor-specific target and the other to CD3-positive T cells or natural killer (NK) cells. Blinatumomab engages CD19 and CD3, performing effective serial lysis. The clinical development program in acute lymphoblastic leukemia (ALL) includes clinical trials in relapsed or refractory (R/R) patients and in B-cell precursor (BCP) ALL patients with measurable residual disease. Several trials are currently being conducted in de novo BCP-ALL, either in induction, consolidation, or before or after hematopoietic stem cell transplant. Combination with other targeted therapies or with other immunotherapeutic approaches are also underway. Several strategies are aimed to optimize the use of blinatumomab either by overcoming the mechanisms of resistance (e.g. inhibition of PD-1/PD-L1) or by improvements in the route of application, among others.

Reduced-Intensity Conditioning with Busulfan and Fludarabine for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Lymphoblastic Leukemia

PURPOSE

Allogeneic hematopoietic stem cell transplantation (HSCT) with optimal conditioning has helped better long-term survival in acute lymphoblastic leukemia (ALL). This study investigated the efficacy and safety of reduced-intensity conditioning (RIC) with busulfan and fludarabine in adult ALL patients unfit for myeloablation.

MATERIALS AND METHODS

Records of 78 patients who underwent HSCT with RIC consisting of 3.2 mg/kg/day of busulfan for 2 or 3 days and 30 mg/m²/day of fludarabine for 5 or 6 days were analyzed.

RESULTS

The median age at diagnosis was 49 years. Over a median follow-up of 22 months, 2-year estimates of relapse-free survival (RFS) and overall survival were 57.4% and 68.7%, respectively. Multivariate analysis showed a trend of improved RFS in patients with chronic graft-versus-host disease (GVHD) (hazard ratio, 0.53; 95% confidence interval, 0.26-1.08; p=0.080). The cumulative incidences of relapse and non-relapse mortality were 42.9% and 19.6%, respectively and one case of central nervous system relapse was noted. No hepatic veno-occlusive disease was reported. Grade II-IV acute GVHD and any grade chronic GVHD occurred in 21.1% and 41.7%, respectively.

CONCLUSION

RIC with busulfan and fludarabine is an effective and safe conditioning regimen for adult ALL patients unfit for myeloablation.

Chimeric Antigen Receptor T Cell Therapy During the COVID-19 Pandemic

The SARS-CoV-2 coronavirus (COVID-19) pandemic has significantly impacted the delivery of cellular therapeutics, including chimeric antigen receptor (CAR) T cells. This impact has extended beyond patient care to include logistics, administration, and distribution of increasingly limited health care resources. Based on the collective experience of the CAR T-cell Consortium investigators, we review and address several questions and concerns regarding cellular therapy administration in the setting of COVID-19 and make general recommendations to address these issues. Specifically, we address (1) necessary resources for safe administration of cell therapies; (2) determinants of cell therapy utilization; (3) selection among patients with B cell non-Hodgkin lymphomas and B cell acute lymphoblastic leukemia; (4) supportive measures during cell therapy administration; (5) use and prioritization of tocilizumab; and (6) collaborative care with referring physicians. These recommendations were carefully formulated with the understanding that resource allocation is of the utmost importance, and that the decision to proceed with CAR T cell therapy will require extensive discussion of potential risks and benefits. Although these recommendations are fluid, at this time it is our opinion that the COVID-19 pandemic should not serve as reason to defer CAR T cell therapy for patients truly in need of a potentially curative therapy.

[Safety and efficacy of patients with refractory B-lymphoblastic leukemia treated with anti-CD19 CAR-T cell bridging to allogeneic hematopoietic stem cell transplantation]

Objective: To investigate the efficacy and side effects of anti-CD19 CAR-T cell bridging to allogeneic hematopoietic stem cell transplantation (allo-HSCT) regimen for refractory B-lymphoblastic leukemia. Methods: 10 patients with refractory B-lymphoblastic leukemia with minimal residual disease (MRD) negative after anti-CD19 CAR-T cell treatment, then bridging to allo-HSCT from November 2017 to March 2019 in the Affiliated Cancer Hospital of Zhengzhou University were retrospectively analyzed. Results: ①Among 10 patients, 5 were males and 5 females, with a median age of 23.6 (10-31) years. 9 patients were diagnosed refractory acute lymphoblastic leukemia and the other one was chronic lymphoblastic leukemia. 10 patients reached MRD negative 30 days after anti-CD19 CAR-T cell. ②The donors were identical sibling (2 cases) and haploidentical family member (8 cases) . The median time from MRD negative after CAR-T treatment to transplantation were 32.5 (20-60) days. ③10 patients obtained complete haploidentical engraftment. The median time of neutrophil implantation was 15 (15-21) days, and 19 (17-30) days of platelet implantation. ④ After conditioning, no hepatic venoocclusive disease and hemorrhagic cystitis occurred. One patient had leakage syndrome and got improved after intervention such as limited water entry, albumin supplementation and diuresis. 8 (80%) patients had fever, 2 cases experienced acute graft-versus-host disease (GVHD) grade Ⅱ, 1 case with aGVHD grade Ⅲ. Among 9 survivals, localized chronic GVHD occurred in 8 patients. ⑤The median follow-up was 262 (150-540) days and the estimated 1-years overall survivaln (OS) and disease free survival (DFS) were (90.0±1.0) % and (85.7±1.3) %, respectively. Conclusion: Anti-CD19 CAR-T cell bridging to allo-HSCT regimen is a feasible choice with favorable outcome for refractory B-lymphoblastic leukemia.

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.

Blinatumomab for the Treatment of Adult B-Cell Acute Lymphoblastic Leukemia: Toward a New Era of Targeted Immunotherapy

Several therapeutic advancements in the treatment of B-cell acute lymphoblastic leukemia (ALL) have surfaced in the past decade, primarily driven by an increased understanding of the immunopathobiology of this disease. The clinical use of blinatumomab, a bispecific antibody that coordinates cytotoxic CD3+ T lymphocytes and CD19+ lymphoblasts, has resulted in improved outcomes in both relapsed/refractory and minimal residual disease-positive B-cell ALL. Promising emerging data also demonstrate the efficacy of this agent in the frontline setting and in combination regimens. Uncertainty remains regarding the optimal sequencing and combination of blinatumomab with cytotoxic chemotherapy and other emerging agents. The pharmacology and clinical data on blinatumomab for adult B-cell ALL, both as monotherapy and in combinations, will be reviewed herein.