Relapsed Philadelphia Chromosome-Positive Pre-B-ALL after CD19-Directed CAR-T Cell Therapy Successfully Treated with Combination of Blinatumomab and Ponatinib

Current Insights into CAR T-Cell-Based Therapies for Myelodysplastic Syndrome

Myelodysplastic syndromes (MDS) are due to defective hematopoiesis in bone marrow characterized by cytopenia and dysplasia of blood cells, with a varying degree of risk of acute myeloid leukemia (AML). Currently, the only potentially curative strategy is hematopoietic stem cell transplantation (HSCT). Many patients are ineligible for HSCT, due to late diagnosis, presence of co-morbidities, old age and complications likely due to graft-versus-host disease (GvHD). As a consequence, patients with MDS are often treated conservatively with blood transfusions, chemotherapy, immunotherapy etc. based on the grade and manifestations of MDS. The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized immunotherapy for hematological malignancies, as evidenced by a large body of literature. However, resistance and toxicity associated with it are also a challenge. Hence, there is an urgent need to develop new strategies for immunological and hematopoetic management of MDS. Herein, we discuss current limitations of CAR T-cell therapy and summarize novel approaches to mitigate this. Further, we discuss the in vivo activation of tumor-specific T cells, immune check inhibitors (ICI) and other approaches to normalize the bone marrow milieu for the management of MDS.

Enhanced cellular therapy: revolutionizing adoptive cellular therapy

Enhanced cellular therapy has emerged as a novel concept following the basis of cellular therapy. This treatment modality applied drugs or biotechnology to directly enhance or genetically modify cells to enhance the efficacy of adoptive cellular therapy (ACT). Drugs or biotechnology that enhance the killing ability of immune cells include immune checkpoint inhibitors (ICIs) / antibody drugs, small molecule inhibitors, immunomodulatory factors, proteolysis targeting chimera (PROTAC), oncolytic virus (OV), etc. Firstly, overcoming the inhibitory tumor microenvironment (TME) can enhance the efficacy of ACT, which can be achieved by blocking the immune checkpoint. Secondly, cytokines or cytokine receptors can be expressed by genetic engineering or added directly to adoptive cells to enhance the migration and infiltration of adoptive cells to tumor cells. Moreover, multi-antigen chimeric antigen receptors (CARs) can be designed to enhance the specific recognition of tumor cell-related antigens, and OVs can also stimulate antigen release. In addition to inserting suicide genes into adoptive cells, PROTAC technology can be used as a safety switch or degradation agent of immunosuppressive factors to enhance the safety and efficacy of adoptive cells. This article comprehensively summarizes the mechanism, current situation, and clinical application of enhanced cellular therapy, describing potential improvements to adoptive cellular therapy.

20-Year Steady Increase in Survival of Adult Patients with Relapsed Philadelphia-Positive Acute Lymphoblastic Leukemia Post Allogeneic Hematopoietic Cell Transplantation

PURPOSE

Relapse after allogeneic hematopoietic cell transplantation (allo-HCT) remains the first cause of transplant failure in patients with Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). In other hematologic malignancies, therapeutic advances resulted in significant improvement over time in survival of patients relapsing after transplant.

EXPERIMENTAL DESIGN

We compared outcomes at European Society for Blood and Marrow Transplantation (EBMT) participating centers of 899 adult patients with Ph+ ALL who relapsed between 2000 and 2019 after allo-HCT performed in first complete remission. Median follow-up for alive patients was 56 months.

RESULTS

Overall, 116 patients relapsed between 2000 and 2004, 225 between 2005 and 2009, 294 between 2010 and 2014, and 264 between 2015 and 2019. Patient and transplant characteristics were similar over the four time periods except for a progressive increase in unrelated donors, peripheral blood stem cells, reduced intensity conditioning, and in vivo T-cell depletion and a progressive decrease in total body irradiation. The 2-year overall survival (OS) after relapse increased from 27.8% for patients relapsing between 2000 and 2004 to 54.8% for 2015 and 2019 (P = 0.001). A second allo-HCT within 2 years after relapse was performed in 13.9% of patients resulting in a 2-year OS of 35.9%. In multivariate analysis, OS from relapse was positively affected by a longer time from transplant to relapse and the year of relapse.

CONCLUSIONS

We observed a major progressive improvement in OS from posttransplant relapse for patients with Ph+ ALL over the years, likely multifactorial including transplant-related factors, posttransplant salvage, and improvement in supportive care. These large-scale real-world data can serve as a benchmark for future studies in this setting. See related commentary by Gale, p. 813.

Second- and third-generation tyrosine kinase inhibitors for Philadelphia-positive adult acute lymphoblastic leukemia relapsing post allogeneic stem cell transplantation-a registry study on behalf of the EBMT Acute Leukemia Working Party

Second- and third-generation tyrosine kinase inhibitors (TKI) play an important role in the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL). However, data on feasibility and efficacy of using these drugs for persisting or relapsed Ph + ALL after allogeneic stem cell transplantation (alloSCT) are scarce. Based on the EBMT Acute Leukemia Working Party registry, we evaluated the use of second-/third-generation TKI in 140 patients with Ph + ALL, suffering from measurable residual disease (MRD, n = 6), molecular relapse (MRel, n = 23), or hematological relapse (HRel, n = 111) following alloSCT. Treatment included dasatinib in 104, nilotinib in 18, or ponatinib in 18 patients. Forty-nine patients received TKI monotherapy, while 91 received additional treatment. Toxicity of second-/third-generation TKI post alloSCT was comparable to pretransplant use and could be managed with dose reduction or temporary discontinuation. Response rates were 71% (overall) and 61% (following TKI monotherapy). For the entire cohort, 2- and 5-year overall survival (OS) was 49% and 33%, respectively. OS was comparable among patients treated for persisting MRD/MRel and HRel. Among patients treated with TKI monotherapy, 2- and 5-year OS was 38% and 33%, respectively. The data underscore that second-/third-generation TKI are important compounds for the management of active Ph + ALL post alloSCT.

Nanomedicine-Combined Immunotherapy for Cancer

BACKGROUND

Immunotherapy for cancer includes Chimeric Antigen Receptor (CAR)-T cells, CAR-natural Killer (NK) cells, PD1, and the PD-L1 inhibitor. However, the proportion of patients who respond to cancer immunotherapy is not satisfactory. Concurrently, nanotechnology has experienced a revolution in cancer diagnosis and therapy. There are few clinically approved nanoparticles that can selectively bind and target cancer cells and incorporate molecules, although many therapeutic nanocarriers have been approved for clinical use. There are no systematic reviews outlining how nanomedicine and immunotherapy are used in combination to treat cancer.

OBJECTIVE

This review aims to illustrate how nanomedicine and immunotherapy can be used for cancer treatment to overcome the limitations of the low proportion of patients who respond to cancer immunotherapy and the rarity of nanomaterials in clinical use.

METHODS

A literature review of MEDLINE, PubMed / PubMed Central, and Google Scholar was performed. We performed a structured search of literature reviews on nanoparticle drug-delivery systems, which included photodynamic therapy, photothermal therapy, photoacoustic therapy, and immunotherapy for cancer. Moreover, we detailed the advantages and disadvantages of the various nanoparticles incorporated with molecules to discuss the challenges and solutions associated with cancer treatment.

CONCLUSION

This review identified the advantages and disadvantages associated with improving health care and outcomes. The findings of this review confirmed the importance of nanomedicinecombined immunotherapy for improving the efficacy of cancer treatment. It may become a new way to develop novel cancer therapeutics using nanomaterials to achieve synergistic anticancer immunity.

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.

How I treat adults with advanced acute lymphoblastic leukemia eligible for CD19-targeted immunotherapy

CD19-targeted immunotherapies have drastically improved outcomes for relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (ALL) patients. Such therapies, including blinatumomab and CD19 chimeric antigen receptor (CD19CAR) T cells, yield high remission rates and can bridge to more definitive consolidation therapy with curative intent. Both treatments are approved by the US Food and Drug Administration (FDA) for r/r ALL (CD19CAR T-cell approval is restricted to patients ≤25 years old). Although availability of blinatumomab and CD19CAR T cells has extended options for the treatment of r/r ALL, prioritizing the sequence of these agents on an individual-patient basis may be difficult for the treating physician. Considering each therapy's advantages, limitations, and challenges is necessary when choosing between them. Although patients may receive both blinatumomab and CD19CAR T cells sequentially in cases that fail to respond or subsequently relapse, a proportion of patients treated with CD19-targeted immunotherapy will lose expression of CD19 and will be excluded from receiving the alternative CD19-targeted therapy. Thus, weighing all considerations for each patient before selecting a CD19-targeted immunotherapy is crucial. Here, we discuss real-life scenarios of adults with r/r ALL, in which we selected either blinatumomab or CD19CAR T-cell therapy, and the rationale behind each decision.

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.

Bispecific antibodies in acute lymphoblastic leukemia therapy

INTRODUCTION

Blinatumomab, first in a class of bispecific T-cell engagers, revolutionized treatment paradigm of B-cell precursor relapsed/refractory or minimal residual disease positive acute lymphoblastic leukemia (ALL) in adults and children, inducing deep remissions in a proportion of patients. However, significant numbers of patients do not respond or eventually relapse. Strategies for improvement of treatment outcomes are required.

AREAS COVERED

This review discusses the main structural and functional features of blinatumomab, and its place in the treatment of ALL. Furthermore, prospects to increase the efficacy of blinatumomab are addressed. The developments in the field of bispecific antibodies and their possible implications for treatment of ALL are reviewed.

EXPERT OPINION

Better understanding the mechanisms of response and resistance to blinatumomab might help us to identify the group of patients benefiting most from treatment and to spare potentially toxic subsequent treatment strategies. Data emerging from ongoing clinical trials might change the treatment landscape of ALL and beyond. Early use of blinatumomab in frontline protocols with more advantageous treatment sequences and in combination with other targeted therapies might reduce the failure rates. Exponentially increasing number of novel treatment options and their possible combinations might complicate treatment decision-making without data from randomized trials.

Immunotherapies and Combination Strategies for Immuno-Oncology

The advent of novel immunotherapies in the treatment of cancers has dramatically changed the landscape of the oncology field. Recent developments in checkpoint inhibition therapies, tumor-infiltrating lymphocyte therapies, chimeric antigen receptor T cell therapies, and cancer vaccines have shown immense promise for significant advancements in cancer treatments. Immunotherapies act on distinct steps of immune response to augment the body's natural ability to recognize, target, and destroy cancerous cells. Combination treatments with immunotherapies and other modalities intend to activate immune response, decrease immunosuppression, and target signaling and resistance pathways to offer a more durable, long-lasting treatment compared to traditional therapies and immunotherapies as monotherapies for cancers. This review aims to briefly describe the rationale, mechanisms of action, and clinical efficacy of common immunotherapies and highlight promising combination strategies currently approved or under clinical development. Additionally, we will discuss the benefits and limitations of these immunotherapy approaches as monotherapies as well as in combination with other treatments.

Mechanisms of Relapse After CD19 CAR T-Cell Therapy for Acute Lymphoblastic Leukemia and Its Prevention and Treatment Strategies

Chimeric antigen receptor (CAR) T-cell therapy is highly effective in the treatment of B-cell acute lymphoblastic leukemia (ALL) or B-cell lymphoma, providing alternative therapeutic options for patients who failed to respond to conventional treatment or relapse. Moreover, it can bridge other therapeutic strategies and greatly improve patient prognosis, with broad applicable prospects. Even so, 30–60% patients relapse after treatment, probably due to persistence of CAR T-cells and escape or downregulation of CD19 antigen, which is a great challenge for disease control. Therefore, understanding the mechanisms that underlie post-CAR relapse and establishing corresponding prevention and treatment strategies is important. Herein, we discuss post-CAR relapse from the aspects of CD19-positive and CD19-negative and provide some reasonable prevention and treatment strategies.

Allogeneic stem-cell transplantation with sequential conditioning in adult patients with refractory or relapsed acute lymphoblastic leukemia: a report from the EBMT Acute Leukemia Working Party

Treatment of relapsed/refractory acute lymphoblastic leukemia (RR-ALL) remains a clinical challenge with generally dismal prognosis. Allogeneic stem-cell transplantation using sequential conditioning ("FLAMSA"-like) has shown promising results in relapsed/refractory acute myeloid leukemia, but little is known about its efficacy in RR-ALL. We identified 115 patients (19-66 years) with relapsed (74%) or primary-refractory (26%) ALL allografted from matched related (31%), matched unrelated (58%), or haploidentical donor (11%). Median follow-up was 37 (13-111) months. At day 100, cumulative incidences of grade II-IV/III-IV acute graft-versus-host-disease (GVHD) were 30% and 17%, respectively. Two-year cumulative incidence of chronic GVHD was 25% with 11% extensive cases. Two-year relapse incidence (RI) was 45%, non-relapse mortality was 41%. Two-year leukemia free survival (LFS) was 14%, overall survival (OS) 17%, and GVHD relapse-free survival (GRFS) was 14%. In multivariable analysis, Karnofsky score <90 negatively affected RI, LFS, OS, and GRFS. Conditioning with chemotherapy alone, compared with total body irradiation (TBI) negatively affected RI (HR = 3.3; p = 0.008), LFS (HR = 1.94; p = 0.03), and OS (HR = 2.0; p = 0.03). These patients still face extremely poor outcomes, highlighting the importance of incorporating novel therapies (e.g., BITE antibodies, inotuzumab, CAR-T cells). Nevertheless, patients with RR-T-cell ALL remain with an unmet treatment need, for which TBI-based sequential conditioning could be one of few available options.