Long-term follow-up of blinatumomab in patients with relapsed/refractory Philadelphia chromosome-positive B-cell precursor acute lymphoblastic leukaemia: Final analysis of ALCANTARA study

How I treat adult Ph+ ALL

ABSTRACT

The Philadelphia (Ph) chromosome is one of the few genetic aberrations in which a casualty has been proven and, as such, represents a success in the history of medicine. This is also evident in the setting of Ph+ acute lymphoblastic leukemia (ALL), the most frequent genetic subgroup in adult ALL, whose incidence increases with age and whose prognosis, before the advent of tyrosine kinase inhibitors (TKIs), was particularly poor. The outcome and management of patients with Ph+ ALL have greatly improved since the incorporation of first-, second-, and third-generation TKIs in the therapeutic backbone and is further changing with the more recent introduction of immunotherapy. This allows for long-term survival rates currently ranging between 75% and 80%. The clinical scenario of adult Ph+ ALL has thus changed profoundly, and new challenges are emerging. In this article, illustrative clinical cases are used to discuss the current role of systemic chemotherapy and allogeneic stem cell transplant, the difficulty in treating central nervous system relapses and, more in general, relapses in the current therapeutic era, and the possibility of stopping TKIs. Finally, the challenges related to an optimal management of these patients are discussed.

How I treat Philadelphia chromosome-like acute lymphoblastic leukemia in children, adolescents, and young adults

ABSTRACT

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) represents a high-risk B-lineage ALL subtype characterized by adverse clinical features and poor relapse-free survival despite risk-adapted multiagent chemotherapy regimens. The advent of next-generation sequencing has unraveled the diversity of kinase-activating genetic drivers in Ph-like ALL that are potentially amenable to personalized molecularly-targeted therapies. Based upon robust preclinical data and promising case series of clinical activity of tyrosine kinase inhibitor (TKI)-based treatment in adults and children with relevant genetic Ph-like ALL subtypes, several clinical trials have investigated the efficacy of JAK- or ABL-directed TKIs in cytokine receptor-like factor 2 (CRLF2)/JAK pathway-mutant or ABL-class Ph-like ALL, respectively. The final results of these trials are pending, and standard-of-care therapeutic approaches for patients with Ph-like ALL have yet to be defined. In this How I Treat perspective, we review recent literature to guide current evidence-based treatment recommendations via illustrative clinical vignettes of children, adolescents, and young adults with newly diagnosed or relapsed/refractory Ph-like ALL, and we further highlight open and soon-to-open trials investigating immunotherapy and TKIs specifically for this high-risk patient population.

Cardiovascular toxicities associated with novel cellular immune therapies

ABSTRACT

Over the past decade, T-cell-directed therapies, including chimeric antigen receptor T-cell (CAR-T) and bispecific T-cell engager (BTE) therapies, have reshaped the treatment of an expanding number of hematologic malignancies, whereas tumor-infiltrating lymphocytes, a recently approved cellular therapy, targets solid tumor malignancies. Emerging data suggest that these therapies may be associated with a high incidence of serious cardiovascular toxicities, including atrial fibrillation, heart failure, ventricular arrhythmias, and other cardiovascular toxicities. The development of these events is a major limitation to long-term survival after these treatments. This review examines the current state of evidence, including reported incidence rates, risk factors, mechanisms, and management strategies of cardiovascular toxicities after treatment with these novel therapies. We specifically focus on CAR-T and BTE therapies and their relation to arrhythmia, heart failure, myocarditis, bleeding, and other major cardiovascular events. Beyond the relationship between cytokine release syndrome and cardiotoxicity, we describe other potential mechanisms and highlight key unanswered questions and future directions of research.

Results of the Simultaneous Combination of Ponatinib and Blinatumomab in Philadelphia Chromosome-Positive ALL

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.In this analysis, we update our experience with the chemotherapy-free regimen of blinatumomab and ponatinib in 60 patients with newly diagnosed Philadelphia chromosome (Ph)-positive ALL. At a median follow-up of 24 months, the complete molecular response rate by reverse transcriptase-polymerase chain reaction was 83% (67% at the end of course one), and the rate of measurable residual disease negativity by next-generation clono-sequencing was 98% (45% at the end of course one). Only two patients underwent hematopoietic stem cell transplantation (HSCT). Seven patients relapsed: two with systemic disease, four with isolated CNS relapse, and one with extramedullary Ph-negative, CRLF2-positive pre-B ALL. The estimated 3-year overall survival rate was 91% and event-free survival rate was 77%. Three patients discontinued blinatumomab because of adverse events (related, n = 1; unrelated, n = 2) and nine discontinued ponatinib because of cerebrovascular ischemia, coronary artery stenosis, persistent rash, elevated liver function tests with drug-induced fatty liver, atrial thrombus, severe arterial occlusive disease of lower extremities, pleuro-pericardial effusion, and debilitation. In conclusion, the simultaneous combination of ponatinib and blinatumomab is a highly effective and relatively safe nonchemotherapy regimen. This regimen also reduces the need for intensive chemotherapy and HSCT in first remission in the majority of patients.

A review of immunotargeted therapy for Philadelphia chromosome positive acute lymphoblastic leukaemia: making progress in chemotherapy-free regimens

Philadelphia chromosome-positive acute lymphoblastic leukemia (PH + ALL) is the most common cytogenetic abnormality of B-ALL in adults and is associated with poor prognosis. Previously, the only curative treatment option in PH + ALL was allogeneic hematopoietic stem cell transplantation (Allo-HSCT). Since 2000, targeted therapy combined with chemotherapy, represented by the tyrosine kinase inhibitor Imatinib, has become the first-line treatment for PH + ALL. Currently, the remission rate and survival rate of Imatinib are superior to those of simple chemotherapy, and it can also improve the efficacy of transplantation. More recently, some innovative immune-targeted therapy greatly improved the prognosis of PH + ALL, such as Blinatumomab and Inotuzumab Ozogamicin. For patients with ABL1 mutations and those who have relapsed or are refractory to other treatments, targeted oral small molecule drugs, monoclonal antibodies, Bispecific T cell Engagers (BiTE), and chimeric antigen receptor (CAR) T cells immunotherapy are emerging as potential treatment options. These new therapeutic interventions are changing the treatment landscape for PH + ALL. In summary, this review discusses the current advancements in targeted therapeutic agents shift in the treatment strategy of PH + ALL towards using more tolerable chemotherapy-free induction and consolidation regimens confers better disease outcomes and might obviate the need for HSCT.

Immunotherapy in first line treatment of adult acute lymphoblastic leukemia

PURPOSE OF REVIEW

The use of immunotherapy in recent years has changed the paradigm of treatment in patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), improving outcomes in the relapsed/refractory setting. New strategies are incorporating immunotherapy into front-line regimens to reduce the toxicity of chemotherapy, prolong survival and increase the possibility of treating older patients. The aim of this review was to describe the new strategies, which have incorporated these drugs into front-line regimens for BCP-ALL patients.

RECENT FINDINGS

Recent studies have demonstrated that immunotherapy can be included in front-line induction, consolidation and/or maintenance regimens for the treatment of BCP-ALL patients by its addition to chemotherapy, by substituting some chemotherapy cycles or even including immunotherapy in chemotherapy-free strategies.

SUMMARY

The implications of these relevant findings will allow treating older patients, reducing the toxicity of chemotherapy and increasing patient outcomes. In addition, these findings have raised the possibility of avoiding the need for hematologic stem cell transplant in some selected patients.

Bispecific antibodies: advancing precision oncology

Bispecific antibodies (bsAbs) are engineered molecules designed to target two different epitopes or antigens. The mechanism of action is determined by the bsAb molecular targets and structure (or format), which can be manipulated to create variable and novel functionalities, including linking immune cells with tumor cells, or dual signaling pathway blockade. Several bsAbs have already changed the treatment landscape of hematological malignancies and select solid cancers. However, the mechanisms of resistance to these agents are understudied and the management of toxicities remains challenging. Herein, we review the principles in bsAb engineering, current understanding of mechanisms of action and resistance, data for clinical application, and provide a perspective on ongoing challenges and future developments in this field.

A critical review of management of allogeneic transplant-eligible adults with Ph+ acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) in 20%-30% of adult patients contains the Philadelphia (Ph+) chromosome. Historically, Ph+ ALL denoted a markedly inferior outcome and long-term survival in the absence of an allograft was uncommon. However, the advent of targeted therapy directed against the BCR::ABL1 fusion protein with various tyrosine kinase inhibitors (TKIs) has markedly improved the prognosis, resulting in a number of treatment controversies in allograft-eligible patients. Which is the best TKI to use in induction? What is the clinical relevance of the subdivision of Ph+ ALL into multilineage vs lymphoid types? Do all patients in first morphological complete remission (CR1) after induction and consolidation with chemotherapy/TKI require an allograft? If not, what risk factors predict a poor outcome without an allograft? Can chemotherapy-free approaches, such as blinatumomab in conjunction with more potent TKIs, obviate the need for an allograft in high-risk patients? What is the best strategy to deal with persistent or emerging minimal residual disease both pre- and post-transplant? Is maintenance TKI indicated in all patients post allograft? Can salvage therapy and a subsequent allograft cure patients who relapse after not being transplanted in CR1? This manuscript reviews the latest data influencing contemporary management and discusses these controversies.

Philadelphia-chromosome positive acute lymphoblastic leukemia: ten frequently asked questions

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) constitutes a distinctive cytogenetic entity associated with challenging outcomes, particularly in adult patients. Current upfront chemotherapy-tyrosine kinase inhibitor (TKI)-based therapies include first, second and third-generation TKIs that have revolutionized patient outcomes including molecular remission and overall survival. Chemotherapy-free regimens such as blinatumomab-dasatinib or blinatumomab-ponatinib offer exciting possibilities, yet challenges arise, particularly in preventing central nervous system relapse. Monitoring measurable residual disease is now a cornerstone particularly using next-generation sequencing (NGS)-Clonoseq for accurate assessment. Controversy regarding the ability to omit consolidation with allogeneic stem cell transplantation, specifically for patients achieving early molecular remission, is related to the excellent survival achieved with novel combinations in the upfront setting, however challenged by the lower disease control when transplant is utilized beyond first remission. Post-transplant maintenance introduces new dilemmas: the optimal TKI, dosing, and duration of therapy are open questions. Meanwhile, a myriad of new combinations and cellular therapies are used for relapsed Ph+ ALL, prompting us to unravel the optimal sequencing of these promising regimen. In this review, we delve into the breakthroughs and controversies in Ph+ ALL with ten commonly asked questions.

MRD in Philadelphia Chromosome-Positive ALL: Methodologies and Clinical Implications

PURPOSE OF REVIEW

Measurable residual disease (MRD) is integral in the management of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). This review discusses the current methods used to evaluate MRD as well as the interpretation, significance, and incorporation of MRD in current practice.

RECENT FINDINGS

New molecular technologies have allowed the detection of MRD to levels as low as 10- 6. The most used techniques to evaluate MRD are multiparametric flow cytometry (MFC), quantitative reverse transcription polymerase chain reaction (RT-qPCR), and high-throughput next-generation sequencing (NGS). Each method varies in terms of advantages, disadvantages, and MRD sensitivity. MRD negativity after induction treatment and after allogeneic hematopoietic cell transplantation (HCT) is an important prognostic marker that has consistently been shown to be associated with improved outcomes. Blinatumomab, a new targeted therapy for Ph + ALL, demonstrates high efficacy in eradicating MRD and improving patient outcomes. In the relapsed/refractory setting, the use of inotuzumab ozogamicin and tisagenlecleucel has shown promise in eradicating MRD. The presence of MRD has become an important predictive measure in Ph + ALL. Current studies evaluate the use of MRD in treatment decisions, especially in expanding therapeutic options for Ph + ALL, including tyrosine kinase inhibitors, targeted antibody therapies, chimeric antigen receptor cell therapy, and HCT.

Current landscape of CD3 bispecific antibodies in hematologic malignancies

Over the past 30 years the incorporation of monoclonal antibody (mAb) treatments into the management of hematologic malignancies has led to significant improvements in patient outcomes. The key limitation of mAb treatments is the necessity for target antigen presentation on major histocompatibility complex (MHC) and costimulatory molecules to elicit a cytotoxic immune response. With the advent of bispecific antibodies (BsAbs), these limitations can be overcome through direct stimulation of cytotoxic T cells, thus limiting tumor cell evasion. BsAbs are rapidly being incorporated into treatment regimens for hematologic malignancies, and there are now seven FDA-approved treatments in this class, six of which have been approved in the past year. In this review we describe the function, complications, and clinical trial data available for CD3 BsAbs in the treatment of lymphoma, myeloma, and leukemia.

A Multicentre, Randomized Trial in Adults with de novo Philadelphia Chromosome-Positive Acute Lymphoblastic Leukaemia to Assess the Efficacy of Ponatinib versus Imatinib in Combination with Low-Intensity Chemotherapy, to Compare End of Therapy with Indication for Stem Cell Transplantation versus Tyrosine Kinase Inhibitor, Blinatumomab, and Chemotherapy in Optimal Responders, and to Evaluate Blinatumomab in Suboptimal Responders (GMALL-EVOLVE)

INTRODUCTION

Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ALL) is treated as standard of care (SoC) by imatinib-based treatment combined with induction and consolidation chemotherapy followed by allogeneic stem cell transplantation (SCT) in first remission. The German Multicenter ALL Study Group for Adult ALL (GMALL) reports about a trial to evaluate the impact of ponatinib-based therapy, blinatumomab treatment for suboptimal responders, and the possibility of omission of SoC Allo SCT in optimal responders entitled GMALL-EVOLVE.

METHODS

Herein, imatinib is randomized versus ponatinib as frontline treatment combined with chemotherapy, optimal responders also get randomized between SCT and chemo-immunotherapy, and suboptimal responders receive immunotherapy before SCT. The trial is registered under the EudraCT number 2022-000760-21.

CONCLUSION

This trial will answer several major questions in the treatment of Ph+ALL.

All about blinatumomab: the bispecific T cell engager immunotherapy for B cell acute lymphoblastic leukemia

INTRODUCTION

B cell acute lymphoblastic leukemia-lymphoma (B-ALL) accounts for approximately 75% of ALL cases and is observed in children and adults. Recent advances in disease diagnosis, stratification and prognostication have led to a better characterization of different subgroups of ALL. Notwithstanding the significant improvement in the complete remission rate of B-ALL, patients with minimal residual disease (MRD) and relapsed/refractory (R/R) settings suffer from poor outcomes.

HYPOTHESIS

However, novel therapies, such as agents targeting tyrosine kinases or the CD20 molecule, combination therapies and improved supportive care, have changed the treatment landscape of B-ALL.

METHOD AND RESULTS

Meanwhile, blinatumomab has been FDA-approved for MRD-positive or R/R B-ALL patients. Blinatumomab is a bispecific T cell engager containing the CD3 and CD19 that recognize domains redirecting cytotoxic T cells to lyse B cells. Promising outcomes, including long-term overall survival and improved MRD-negative response rates, have been reported in patients who received this drug. Adding blinatumomab to new ALL regimens seems promising for achieving better outcomes in poor prognosis B-ALL patients. Nevertheless, the neurotoxicity and cytokine release syndrome are the two major adverse events following the blinatumomab therapy.

CONCLUSION

This review summarizes the function and effectiveness of blinatumomab in R/R and MRD positive B-ALL patients. Furthermore, blinatumomab's positive and negative aspects as a novel therapy for B-ALL patients have been briefly discussed.

Pneumocystis jirovecii Pneumonia Secondary to Blinatumomab Therapy: A Case Report

INTRODUCTION

With the increasing use of blinatumomab in relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL), including minimal residual disease (MRD)-positive cases, awareness of its adverse effects has gradually improved. Pneumocystis jirovecii pneumonia (PCP) associated with blinatumomab therapy is rare.

CASE PRESENTATION

We present a case of PCP in a patient undergoing blinatumomab therapy. A 70-year-old female diagnosed with Philadelphia-like CRLF2 overexpression B-cell precursor ALL received blinatumomab as consolidation therapy after achieving complete remission with prior induction chemotherapy. On the second day of blinatumomab infusion, she developed intermittent low-grade fever, and chest computed tomography (CT) revealed subtle infiltrates and nodules. Despite empiric trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis, she progressed to significant shortness of breath and type I respiratory failure, with increased lactate dehydrogenase and β-D-glucan assays. Chest CT showed diffuse ground-glass opacities with scattered small nodules. The dry cough prompted next-generation sequencing of peripheral blood, which tested positive for pneumocystis jirovecii without evidence of other pathogens. Consequently, the patient was diagnosed with PCP. The first cycle of blinatumomab had to be discontinued, and therapeutic dosages of TMP-SMX and dexamethasone were administered, resulting in full recovery and stable condition during follow-ups.

CONCLUSION

PCP is rare in B-cell precursor ALL patients receiving blinatumomab therapy but manifests with early onset and rapid disease progression. Despite prophylaxis, PCP infection cannot be ignored during blinatumomab therapy. Therefore, heightened attention is warranted when using blinatumomab therapy.

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.

Blinatumomab differentially modulates peripheral blood and bone marrow immune cell repertoire: A Campus ALL study

Blinatumomab is the first bi-specific T-cell engager approved for relapsed or refractory B-cell precursor acute lymphoblastic leukaemia (B-ALL). Despite remarkable clinical results, the effects of blinatumomab on the host immune cell repertoire are not fully elucidated. In the present study, we characterized the peripheral blood (PB) and, for the first time, the bone marrow (BM) immune cell repertoire upon blinatumomab treatment. Twenty-nine patients with B-ALL received blinatumomab according to clinical practice. Deep multiparametric flow cytometry was used to characterize lymphoid subsets during the first treatment cycle. Blinatumomab induced a transient redistribution of PB effector T-cell subsets and Treg cells with a persistent increase in cytotoxic NK cells, which was associated with a transient upregulation of immune checkpoint receptors on PB CD4 and CD8 T-cell subpopulations and of CD39 expression on suppressive Treg cells. Of note, BM immune T-cell subsets showed a broader post-treatment subversion, including the modulation of markers associated with a T-cell-exhausted phenotype. In conclusion, our study indicates that blinatumomab differentially modulates the PB and BM immune cell repertoire, which may have relevant clinical implications in the therapeutic setting.

SOHO State of the Art Updates and Next Questions | Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia in Adults: Therapeutic Options and Challenges in 2023

The therapeutic landscape of Philadelphia chromosome positive acute lymphoblastic leukemia (ALL) for adults has dramatically changed over the past 2 decades; the emergence of newer generations of tyrosine kinase inhibitors and incorporation of targeted immunotherapies into front-line therapy have significantly improved outcomes to the point where an argument can be made that this entity may no longer be considered a high-risk ALL subgroup. In this review article, we discuss different front-line regimens (both intensive and deintensified regimens including chemotherapy-free regimens). We also review disease monitoring strategies, discuss the role of allogeneic hematopoietic stem cell transplantation, and discuss the rapidly changing therapeutic landscape for patients with relapsed disease.

Survival outcomes in patients with relapsed/refractory or MRD-positive B-cell acute lymphoblastic leukemia treated with blinatumomab

Blinatumomab has demonstrated significant efficacy in adult and pediatric patients with relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-cell ALL) and patients with measurable residual disease (MRD). This review aimed to compare median relapse-free survival (RFS) and median overall survival (OS) in adult and pediatric patients with R/R or MRD-positive B-cell ALL from pivotal studies [MT-103-211 and TOWER for adults with Philadelphia chromosome (Ph)-negative R/R B-cell ALL, ALCANTARA for adults with Ph-positive R/R B-cell ALL, MT-103-203 for adults with MRD-positive B-cell ALL, and MT-103-205 for pediatric patients with R/R B-cell ALL], with the median RFS and OS from retrospective analyses, country or ethnicity-specific studies, and studies based on real-world evidence (RWE) identified from a literature search. Adults with Ph-negative R/R B-cell ALL who received blinatumomab as first salvage demonstrated a numerically longer median OS compared with that in patients from pivotal studies (MT-103-211 and TOWER) without additional safety concerns. In pediatric patients with R/R B-cell ALL treated with blinatumomab, the median RFS and OS from retrospective analyses and country/ethnicity-specific studies were comparable with the median RFS and OS from the pivotal study MT-103-205. The median RFS and OS from RWE studies in adults with R/R B-cell ALL were numerically longer than the median RFS and OS from pivotal studies (MT-103-211, TOWER, and ALCANTARA); however, this trend was not observed in pediatric patients with R/R B-cell ALL. In conclusion, this analysis identified first salvage adults with Ph-negative R/R B-cell ALL as particularly well-suited for treatment with blinatumomab since survival outcomes from retrospective analyses reported in this patient subgroup were numerically better compared with those from pivotal studies without additional safety signals.

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.

Infectious complications during monoclonal antibodies treatments and cell therapies in Acute Lymphoblastic Leukemia

Infections represent one of the most frequent complications during the treatment of patients with Acute Lymphoblastic Leukemia (ALL): of these, almost half develop an infectious event in the majority of cases in induction. The new monoclonal and bispecific antibodies and CAR-T, besides offering new perspectives in the overall survival and disease-free survival of patients, may also transform the epidemiology of infections in ALL by improving the toxicity of treatments. In this review, we examined studies published in the literature over the past 12 years and described the infectious complications of therapy with Blinatumomab, Inotuzumab, Rituximab and CAR-T in adult and pediatric patients with ALL. Infections are less frequent than in traditional chemotherapy treatment with vincristine, corticosteroids and anthracyclines, which has been the backbone of therapy for patients with ALL for years. On the other hand, the infection scenario in the CAR-T setting is quite peculiar: In these patients, infections are more frequent in the first month after infusion and are predominantly bacterial. As the time moves away from day zero, viral infections become more frequent, occurring mainly in patients who have had prolonged cytopenia and major cytokine release syndrome.

SOHO State of the Art Updates and Next Questions | Optimal Timing of Blinatumomab for the Treatment of B-Acute Lymphoblastic Leukemia

Blinatumomab is a CD19 targeting bi-specific T-cell engager antibody construct developed for the treatment of CD19 expressing B-cell malignancies. Numerous adult and pediatric B-ALL clinical trials have demonstrated blinatumomab's efficacy in the relapse setting as well as in patients with residual disease after upfront chemotherapy. The safety profile of blinatumomab is also favorable, making it a feasible option for most patients. Several key questions remain, including the role of blinatumomab as a replacement for toxic elements of standard chemotherapy regimens in the upfront setting, its role as a bridge to hematopoietic stem cell transplantation, or whether previous blinatumomab impacts the efficacy of subsequent CAR-T cell therapy.

Efficacy and Safety of Blinatumomab for the Treatment of Relapsed/Refractory Acute Lymphoblastic Leukemia: A Systemic Review and Meta-Analysis

OBJECTIVE

The aim was to evaluate the efficacy and safety of blinatumomab monotherapy for the treatment of relapsed/refractory acute lymphoblastic leukemia (R/R B-ALL).

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched to collect clinical studies related to blinatumomab. The primary outcome measures were complete remission (CR), and minimal residual disease (MRD) response. Prognostic indicators included overall survival (OS) and relapse-free survival time (RFS). Grade ≥3 adverse reactions were mainly analyzed for safety, including cytokine release syndrome (CRS), neurological events and hematological toxicity. The heterogeneity was quantified by I² statistic, which reflected the proportion of the true heterogeneity to the variance of the total effect size. Studies were considered heterogeneous if the I² statistic was greater than 50%, and conversely, studies were homogeneous.

RESULTS

A total of 18 studies involving 1,373 patients were included. The analysis results showed a CR rate of 54% (95%CI:44%-64%) and an MRD response rate of 43% (95%CI:34%-51%). The CR rate was higher in patients with bone marrow (BM) blast <50% than in patients with BM blast ≥50% (71% vs. 34%). The median OS and RFS were 8.16 months (95%CI:6.64-9.69) and 6.02 months (95%CI:4.63-7.41), respectively. For safety analysis, the incidence of grade ≥3 adverse events (AEs) was 80% (95%CI:72%-88%), the incidence of grade ≥3 neurological toxicity was 7% (95%CI:4%-11%), and the incidence of grade ≥3 CRS was 3% (95%CI:2%-5%). However, the mixture of retrospective and prospective studies led to heterogeneity to some extent in this meta-analysis.

CONCLUSION

Blinatumomab is effective in the treatment of R/R B-ALL with a controlled occurrence of AEs and a reliable safety profile.

Bispecific T-Cell Engagers Therapies in Solid Tumors: Focusing on Prostate Cancer

Over the past decade, immunotherapy has demonstrated an impressive improvement in treatment outcomes for multiple cancers. Following the landmark approvals for use of immune checkpoint inhibitors, new challenges emerged in various clinical settings. Not all tumor types harbor immunogenic characteristics capable of triggering responses. Similarly, many tumors' immune microenvironment allows them to become evasive, leading to resistance and, thus, limiting the durability of responses. To overcome this limitation, new T-cell redirecting strategies such as bispecific T-cell engager (BiTE) have become attractive and promising immunotherapies. Our review provides a comprehensive perspective of the current evidence of BiTE therapies in solid tumors. Considering that immunotherapy has shown modest results in advanced prostate cancer to date, we review the biologic rationale and promising results of BiTE therapy in this clinical setting and discuss potential tumor-associated antigens that may be integrated into BiTE construct designs. Our review also aims to evaluate the advances of BiTE therapies in prostate cancer, illustrate the major obstacles and underlying limitations, and discuss directions for future research.

Treatment de-escalation in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia: the emerging role of chemotherapy-free regimens

The management of Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) has witnessed major progress over the past two decades. Initially, the incorporation of the first-generation BCR::ABL1 tyrosine kinase inhibitor (TKI) imatinib into intensive chemotherapy regimens improved outcomes compared with chemotherapy alone. The combinations of chemotherapy with second- or third-generation TKIs further improved outcomes, with higher rates of complete molecular remission (CMR) and superior survival. The combination of ponatinib plus chemotherapy resulted in durable remissions and prolonged long-term survival, even in patients who did not receive allogeneic stem cell transplantation (SCT). The promising results seen with later-generation TKIs have caused many to re-evaluate the role of allogeneic SCT for patients who achieve CMR with potent TKI regimens. Recently, the chemotherapy-free combinations of blinatumomab plus TKIs were shown to be safe and effective in newly diagnosed Ph-positive ALL, sparing patients the toxicities associated with intensive chemotherapy. In particular, encouraging early results have been seen with the combination of blinatumomab plus ponatinib, suggesting that this regimen may represent a chemotherapy-free and SCT-sparing strategy for patients with Ph-positive ALL. Herein, we discuss the current evidence for frontline therapies of Ph-positive ALL, the treatment de-escalation strategies over time, and the role of allogeneic SCT in view of the emergence of newer chemotherapy-free regimens using potent TKIs.

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.

Superior survival outcome of blinatumomab compared with conventional chemotherapy for adult patients with relapsed or refractory B-cell precursor acute lymphoblastic leukemia: a propensity score-matched cohort analysis

Background

Blinatumomab showed a higher complete remission (CR) rate and a safe bridging to allogeneic hematopoietic cell transplantation (allo-HCT) in adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (R/R BCP-ALL).

Objectives

We tried to analyze the outcome of blinatumomab compared with the real-world historical data. We expected superior outcome of blinatumomab compared with historical conventional chemotherapy.

Design

We conducted a retrospective study using real-world data in the Catholic Hematology Hospital.

Methods

Total 197 consecutive cases of R/R BCP-ALL were treated with conventional chemotherapy (n = 113) or blinatumomab, which was available since late 2016 (n = 84). Patients who achieved CR underwent allo-HCT if donor was available. We conducted a propensity score-matched cohort analysis using 5 criteria of age, CR duration, cytogenetics, previous allo-HCT, and salvage lines between historical group and blinatumomab.

Results

Each cohort consisted of 52 patients. In blinatumomab group, CR rate was higher (80.8% versus 53.8%, p = 0.006) and more patients proceeded to allo-HCT (80.8% versus 46.2%, p < 0.001). Among the CR patients with available minimal residual disease (MRD) results, 68.6% in blinatumomab group and 40.0% in conventional chemotherapy group were MRD-negative. Regimen-related mortality during the chemotherapy cycles was significantly higher in the conventional chemotherapy group (40.4% versus 1.9%, p < 0.001). Estimated 3-year overall survival (OS) was 33.2% (median, 26.3 months) after blinatumomab, and 15.4% (median, 8.2 months) after conventional chemotherapy (p < 0.001). Estimated 3-year non-relapse mortality were 30.3% and 51.9% (p = 0.004), respectively. In multivariate analysis, CR duration < 12 months showed more relapses and poor OS, and conventional chemotherapy showed higher non-relapse mortality and poor OS.

Conclusions

Matched cohort analysis showed superior outcomes of blinatumomab compared with conventional chemotherapy. However, large numbers of relapses and non-relapse mortalities continue to occur even after blinatumomab followed by allo-HCT. Novel therapeutic strategies are still needed for R/R BCP-ALL.

Blinatumomab in Relapsed/Refractory Burkitt Lymphoma

In patients with relapsed/refractory Burkitt lymphoma (r/r BL), overall survival (OS) is poor, and effective therapies and evidence for the best therapy are lacking. The monoclonal antibody blinatumomab may represent a novel option. However, only limited data on the use of blinatumomab in r/r BL are so far available. This multi-center, retrospective case series investigated nine patients with r/r BL treated with blinatumomab. The safety of blinatumomab was assessed with respect to frequency and severity of adverse effects (AEs) infections, cytokine release syndrome (CRS) and neurotoxicity. Progression-free survival (PFS), OS and overall response rate (ORR) were analyzed to assess efficacy. No AEs > grade 2 occurred, and AEs were generally treatable and fully reversible. The best response to blinatumomab was complete remission in 3/9 patients and partial remission in 2/9, whilst 4/9 presented with progressive disease. Median PFS and OS were 2 and 6 months, respectively, ranging from 5 days to 32 months and 11 days to 32 months, respectively. Blinatumomab treatment was a successful bridging treatment to stem cell transplantation in 3/9 patients. The response to blinatumomab varied widely, and only one patient survived longer term, but activity in patients with r/r BL was evident in some patients, with its use being safe, warranting its prospective investigation.

New developments in ALL in AYA

The outcome for adolescents and young adults (AYA) with acute lymphoblastic leukemia (ALL) has improved, mostly based on the use of pediatric-inspired intensive protocols. Due to increasing disease resistance and treatment-related toxicity with age, further improvements are now expected from the expanding knowledge of ALL biology, more accurate risk stratification, and the early introduction of targeted small molecules and immunotherapy. In the last decade, the rate of AYA with B-cell precursor ALL with undetermined genetic drivers ("B-other") has shrunk from 40% to fewer than 10%. The high-risk subgroup of Philadelphia-like ALL is the most frequent entity diagnosed in this age range, offering a multitude of potentially actionable targets. The timely and accurate identification of these targets remains challenging, however. Early minimal residual disease (MRD) monitoring has become a standard of care for the risk stratification and identification of patients likely to benefit from an allogeneic hematopoietic stem cell transplantation. Recently approved immunotherapies are moving frontline to eradicate MRD, to improve the outcome of high-risk patients, and, eventually, to reduce treatment burden. Comprehensive care programs dedicated to AYA with cancer aim at improving inclusion in specific clinical trials and at giving access to appropriate psychosocial support, fertility preservation, and survivorship programs.

Modern Management Options for Ph+ ALL

Simple Summary

The use of tyrosine kinase inhibitors has represented a major step forward in the therapy of Philadelphia chromosome positive acute lymphoblastic leukemia. Recent improvements in the therapy are focused on early use of third generation tyrosine kinase inhibitors, their combination with immunotherapy, the refined indication of allogeneic hematopoietic stem cell transplantation, the optimal use and duration of maintenance therapy, and the management of patients with molecular or hematological relapse with combination of targeted therapies and immunotherapy, including cellular therapies. Improvements in the assessment of measurable residual disease and in the detection of mutations in the ABL1 domain are contributing to the better selection of the therapy for newly diagnosed as well as for relapsed or refractory patients.

Abstract

Impressive advances have been achieved in the management of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) since the initial concurrent use of imatinib and standard chemotherapy. The attenuation of chemotherapy has proven to be equally effective and less toxic, the use of third generation TKI upfront has improved the frequency of complete molecular response and the survival rate, and the combination of tyrosine kinase inhibitors with immunotherapy has further increased the rate of molecular response to 70–80% after consolidation, which has been translated into a survival rate of 75–90% in recent trials. As a result of these improvements, the role of allogeneic hematopoietic stem cell transplantation is being redefined. The methodology of measurable residual disease assessment and the detection of ABL1 mutations are also improving and will contribute to a more precise selection of the treatment for newly diagnosed and relapsed or refractory (R/R) patients. Finally, new compounds combined with immunotherapeutic approaches, including cellular therapy, are being used as rescue therapy and will hopefully be included in first line therapy in the near future. This article will review and update the modern management of patients with Ph+ ALL.

The pharmacology of blinatumomab: state of the art on pharmacodynamics, pharmacokinetics, adverse drug reactions and evaluation in clinical trials

WHAT IS KNOWN AND OBJECTIVE

Bispecific drugs (BDs) belong to the family of immunotherapies along with checkpoint inhibitors and CAR-T cells. In the field of oncology, BDs are designed to simultaneously bind a tumour antigen on the one side and an antigen present on the surface of effector cells on the other. This review summarizes the information available to date on the first marketed BiTE-format bispecific antibody, blinatumomab BLINCYTO® in acute lymphoblastic leukaemia.

METHODS

A literature search was conducted in the PubMed database by including studies published in English using the term blinatumomab. Furthermore, bibliographies of selected references were also evaluated for relevant articles. Clinical trial (CT) data were retrieved from clinicaltrials.gov (ongoing trials, adverse events [AEs]) and global pharmacovigilance data were retrieved from VigiBase®.

RESULTS AND DISCUSSION

Blinatumomab is a fusion protein which consists of two single-chain variable fragments arranged in tandem: the first binds the CD19 surface antigen of all B cells and the second targets the CD3 antigen of T cells. Binding of blinatumomab to B and T cells induces apoptosis of B cells after secretion of granzymes and perforins by T cells. T-cell activation results in secretion of pro-inflammatory cytokines and upregulation of activation markers and adhesion molecules on the surface of T cells. The major CTs that led to an indication show increased overall survival with blinatumomab with better efficacy in patients in haematological remission with minimal residual disease ≥10^-3 . The major AEs are cytokine release syndrome, neurotoxicity and hypogammaglobulinemia. The three most frequent system organ classes in CTs are haematological, gastrointestinal and general disorders. These results are also found in VigiBase® but neurological disorders and infections appear more frequently in real life.

WHAT IS NEW AND CONCLUSION

This review summarizes the current knowledge of blinatumomab in the literature. The subject of many CTs is to improve the route of administration and expand the indications for treatment.

Treatment of Adults With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia-From Intensive Chemotherapy Combinations to Chemotherapy-Free Regimens: A Review

Importance

With the advent of potent BCR::ABL1 tyrosine kinase inhibitors (TKIs), Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) is now a relatively favorable-risk acute leukemia. In this review, we discuss the current evidence for frontline therapies of Ph-positive ALL, the major principles that guide therapy, and the progress with chemotherapy-free regimens.

Observations

Incorporating TKIs into the chemotherapy regimens of patients with newly diagnosed Ph-positive ALL has led to improved remission rates, higher probability of reaching allogeneic stem cell transplantation (SCT), and longer survival compared with chemotherapy alone. Early achievement of a complete molecular remission (CMR) is an important end point in Ph-positive ALL and identifies patients who have excellent long-term survival and may not need allogeneic SCT. Second-generation TKIs combined with intensive or low-intensity chemotherapy resulted in higher CMR rates compared with imatinib-based regimens. This translated into better outcomes, with less reliance on allogeneic SCT. To further improve the outcomes, the potent third-generation TKI ponatinib was added to chemotherapy. The combination of hyper-CVAD and ponatinib resulted in an overall CMR rate of 84% and a 5-year survival rate of 73% and 86% among patients who did and did not undergo allogeneic SCT, respectively, suggesting that allogeneic SCT may not be needed with this regimen. The recent chemotherapy-free combination of dasatinib and blinatumomab was safe and effective in patients with newly diagnosed Ph-positive ALL and resulted in an estimated 3-year OS rate of 80%; 50% of patients underwent allogeneic SCT. The chemotherapy-free regimen of ponatinib and blinatumomab resulted in a CMR rate of 86% and a 2-year survival rate of 93%, with no relapses or leukemia-related deaths, and with only 1 patient proceeding to allogeneic SCT.

Conclusions and Relevance

The promising results obtained with the chemotherapy-free regimens of blinatumomab plus TKIs question the role of allogeneic SCT in first remission. Patients with Ph-positive ALL who achieve early and deep molecular responses have excellent long-term outcomes and may not benefit from allogeneic SCT.

Bispecific Antibodies in Cancer Immunotherapy: A Novel Response to an Old Question

Immunotherapy has redefined the treatment of cancer patients and it is constantly generating new advances and approaches. Among the multiple options of immunotherapy, bispecific antibodies (bsAbs) represent a novel thoughtful approach. These drugs integrate the action of the immune system in a strategy to redirect the activation of innate and adaptive immunity toward specific antigens and specific tumor locations. Here we discussed some basic aspects of the design and function of bsAbs, their main challenges and the state-of-the-art of these molecules in the treatment of hematological and solid malignancies and future perspectives.

Immunotherapy and Allogeneic Bone Marrow Transplantation in B Acute Lymphoblastic Leukemia: How to Sequence?

Long-term disease control is achieved in 80-90% of patients with acute lymphoblastic leukemia of B origin (B-ALL). About half of adult and 10% of pediatric patients develop refractory or relapsed disease, whereas survival after relapse accounts about 10% in adults and 30-50% in children. Allogeneic bone marrow transplantation offers remarkable benefit in cases with unfavorable outcome. Nevertheless, novel immunotherapeutic options have been approved for patients with adverse prognosis. Immunotherapeutic agents, nowadays, are preferred over standard chemotherapy for patients with relapsed or refractory B-ALL The mode of action, efficacy and safety data of immunotherapeutic agents released, indications and sequence of those therapies over the course of treatment, are herein reviewed.

Role of allogeneic haematopoietic stem cell transplantation in the treatment of adult acute lymphoblastic leukaemia in the era of immunotherapy

ABSTRACT

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently the standard of care for adult acute lymphoblastic leukemia (ALL) patients. In recent years, with the continuous development of immunotherapy, such as chimeric antigen receptor T cells, blinatumomab, and inotuzumab ozogamicin, a series of vital clinical studies have confirmed its high response rate and favorable outcomes for ALL. Although the emergence of immunotherapy has expanded relapsed or refractory (r/r) ALL patients' opportunities to receive allo-HSCT, allo-HSCT is associated with potential challenges. In this review, the role of allo-HSCT in the treatment of adult ALL in the era of immunotherapy will be discussed.

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.

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.

Use of blinatumomab and CAR T-cell therapy in children with relapsed/refractory leukemia: A case series study

BACKGROUND

The 5-year event-free survival rate for childhood acute lymphoblastic leukemia (ALL) has increased to more than 85%. However, the 5-year overall survival rate in children with relapsed/refractory ALL did not exceed 50%. In the past decade, immunotherapies (such as blinatumomab and chimeric antigen receptor T-cell therapy) were approved for relapsed/refractory B-ALL, transforming the treatment environment for children with relapsed/refractory ALL.

OBJECTIVE

This study aimed to explore how immunotherapy can be incorporated into salvage regimens for pediatric patients with relapsed/refractory ALL by retrospectively analyzing the diagnosis and treatment process of seven children with relapsed/refractory leukemia and observing the side effects of the two strategies and long-term survival.

METHODS

The clinical features and treatment responses of patients aged <14 years with relapsed/refractory leukemia who received immunotherapy (including Chimeric Antigen Receptor T cell treatment and blinatumomab) at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology between February 2014 and April 2022 were retrospectively analyzed.

RESULTS

Seven children underwent immunotherapy. Five patients received immunotherapy and sequential allogeneic hematopoietic stem cell transplantation (HSCT), whereas the other two received only immunotherapy. Five patients achieved complete remission (71.4%). None of the patients had severe cytokine release syndrome. However, one developed grade 3 immune effector cell-associated neurotoxicity syndrome with prior leukoencephalopathy. The median follow-up period was 541 days (range, 186-3,180 days). No deaths were related to treatment. Three patients relapsed, two had CD19-negative recurrences, and the third showed CD19 antigen reduction. One patient died after disease progression, whereas the other died of HSCT-related complications. One patient abandoned the treatment after relapse and was lost to follow-up.

CONCLUSION

Blinatumomab and CAR T-cell therapy showed excellent remission rates and manageable toxicity in pediatric patients with relapsed/refractory leukemia. However, the duration of the remission was limited. Therefore, further prospective randomized clinical studies should be conducted to improve the long-term efficacy of immunotherapy.

Extramedullary disease relapse and progression after blinatumomab therapy for treatment of acute lymphoblastic leukemia

BACKGROUND

Blinatumomab has demonstrated encouraging activity in relapsed/refractory (r/r) and minimal residual disease-positive (MRD+) acute lymphoblastic leukemia (ALL). Extramedullary disease (EMD) relapse or relapse with CD19- disease has been observed after blinatumomab therapy in patients with r/r or MRD+ ALL. However, the pathophysiology and risk factors of treatment failure are not fully understood.

METHODS

This study retrospectively reviewed the outcomes of adult patients with B-cell ALL treated with blinatumomab (n = 132) for either r/r (n = 103) or MRD+ disease (n = 29) at the authors' center (2013-2021) and analyzed factors associated with treatment response and EMD failure.

RESULTS

The overall response rate was 64%. A lower marrow blast burden before blinatumomab (P = .049) and no history of previous EMD (P = .019) were significantly associated with a higher response. Among the patients who responded to blinatumomab, 56% underwent consolidation with allogeneic transplantation. Blinatumomab failure was observed in 89 patients; 43% of these patients (n = 38) either progressed or relapsed at extramedullary sites. A history of extramedullary involvement (53% vs 24%; P = .005) and retention of CD19 expression at the time of relapse/progression (97% vs 74%; P = .012) were associated with a higher risk for extramedullary failure. Central nervous system (CNS) failure after blinatumomab was encountered in 39% of the patients with EMD.

CONCLUSIONS

A history of EMD predicted an inferior response to blinatumomab therapy with a higher risk for relapse/progression at extramedullary sites (particularly CNS). Consolidation with allogenic transplantation in patients who primarily responded to blinatumomab did not abrogate the risk of extramedullary relapse. The incorporation of extramedullary assessment and the intensification of CNS prophylaxis may help in addressing extramedullary failure.

LAY SUMMARY

Extramedullary failure is common during blinatumomab therapy for relapsed/refractory acute lymphoblastic leukemia. A history of extramedullary disease predicts an inferior response to blinatumomab therapy and a higher risk for relapse/progression at extramedullary sites. Most extramedullary failure cases retain CD19 expression.

Inotuzumab ozogamicin with bosutinib for relapsed or refractory Philadelphia chromosome positive acute lymphoblastic leukemia or lymphoid blast phase of chronic myeloid leukemia

Relapsed/refractory (R/R) Philadelphia chromosome positive acute lymphoblastic leukemia (Ph + ALL) and lymphoid blast phase of chronic myeloid leukemia (LBP-CML) have poor outcomes. We designed a phase 1/2 study combining inotuzumab ozogamicin with bosutinib for this patient population. Patients with T315I mutation were excluded. Bosutinib was administered daily at three dose levels (300 mg/d, 400 mg/d, 500 mg/d) in a 3 + 3 design. Inotuzumab ozogamicin was dosed weekly during cycle one, and once every 4 weeks subsequently for a total of six cycles. The primary objective was to determine the safety and the maximum tolerated dose (MTD) of bosutinib in combination with inotuzumab ozogamicin. Eighteen patients were enrolled (Ph-positive ALL, n = 16; LBP-CML, n = 2). The median age was 62 years (range, 19-74) and the median number of prior therapies was one (range, 1-5). Dose limiting toxicities included grade 3 skin rash and bosutinib 400 mg daily was determined as the MTD. The most frequent grade 3/4 treatment-emergent adverse events were thrombocytopenia (60%) and neutropenia (38%). A complete response (CR) / CR with incomplete count recovery (CRi) was achieved in 15/18 (83%) patients; 11/18 (61%) patients achieved negative measurable residual disease by flow cytometry. Complete molecular response was noted in 10/18 (56%) patients. The 30-day mortality was 0%. After a median follow-up of 44 months, the median duration of response and overall survival were 7.7 months and 13.5 months, respectively. Six patients had a subsequent allogeneic stem cell transplant. No patient developed veno-occlusive disease. Inotuzumab ozogamicin with bosutinib was well tolerated in R/R Ph-positive ALL and LBP-CML.

Association between measurable residual disease kinetics and outcomes of Philadelphia chromosome-positive acute lymphoblastic leukemia

The prognosis of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) has improved dramatically. Although measurable residual disease (MRD) kinetics during pretransplant treatment has been recently reported to correlate with patient outcomes, it is unclear whether prognosis is better if the MRD falls below the detection sensitivity soon after induction therapy. We retrospectively analyzed data of 37 Ph + ALL patients who were treated with autologous or allogeneic stem cell transplantation (auto-SCT, allo-SCT) at our institute from 2003 to 2019. Based on MRD kinetics, patients were divided into three groups: early responders (MRD became negative after induction therapy [n = 10, 27.0%]); late responders (MRD remained positive after induction therapy and became negative just before SCT [n = 12, 32.4%]); and poor responders (MRD was positive until just before SCT [n = 15, 40.5%]). The 5-year disease-free survival (DFS) rates for the three groups were 80.0%, 60.0%, and 29.9%, respectively (P = 0.037). The 5-year overall survival rates were not significantly different. The 5-year relapse rates were 0.0%, 31.7%, and 49.5%, respectively (P = 0.045). Non-relapse mortality (NRM) rates were similar among the three groups. Subgroup analysis for the cases that received posttransplantation tyrosine kinase inhibitor maintenance therapy revealed that DFS was similarly dependent on MRD kinetics (P = 0.022). This study clarified that MRD kinetics was a significant prognosticator for DFS and relapse rate in Ph + ALL.

Haematopoietic Stem Cell Transplantation in Adolescents and Young Adults With Acute Lymphoblastic Leukaemia: Special Considerations and Challenges

Adolescents and young adults (AYAs) represent a challenging group of acute lymphoblastic leukaemia (ALL) patients with specific needs. While there is growing evidence from comparative studies that this age group profits from intensified paediatric-based chemotherapy, the impact and optimal implementation of haematopoietic stem cell transplantation (HSCT) in the overall treatment strategy is less clear. Over recent years, improved survival rates after myeloablative allogeneic HSCT for ALL have been reported similarly for AYAs and children despite differences in transplantation practise. Still, AYAs appear to have inferior outcomes and an increased risk of treatment-related morbidity and mortality in comparison with children. To further improve HSCT outcomes and reduce toxicities in AYAs, accurate stratification and evaluation of additional or alternative targeted treatment options are crucial, based on specific molecular and immunological characterisation of ALL and minimal residual disease (MRD) assessment during therapy. Age-specific factors such as increased acute toxicities and poorer adherence to treatment as well as late sequelae might influence treatment decisions. In addition, educational, social, work, emotional, and sexual aspects during this very crucial period of life need to be considered. In this review, we summarise the key findings of recent studies on treatment approach and outcomes in this vulnerable patient group after HSCT, turning our attention to the different approaches applied in paediatric and adult centres. We focus on the specific needs of AYAs with ALL regarding social aspects and supportive care to handle complications as well as fertility issues. Finally, we comment on potential areas of future research and concisely debate the capacity of currently available immunotherapies to reduce toxicity and further improve survival in this challenging patient group.