Clinical data, limitations and perspectives on chimeric antigen receptor T-cell therapy in multiple myeloma

The Function of NK Cells in Tumor Metastasis and NK Cell-Based Immunotherapy

Metastatic tumors cause the most deaths in cancer patients. Treating metastasis remains the primary goal of current cancer research. Although the immune system prevents and kills the tumor cells, the function of the immune system in metastatic cancer has been unappreciated for decades because tumors are able to develop complex signaling pathways to suppress immune responses, leading them to escape detection and elimination. Studies showed NK cell-based therapies have many advantages and promise for fighting metastatic cancers. We here review the function of the immune system in tumor progression, specifically focusing on the ability of NK cells in antimetastasis, how metastatic tumors escape the NK cell attack, as well as the recent development of effective antimetastatic immunotherapies.

[Management of neurotoxicity following CAR-T cell therapy: Recommendations of the SFGM-TC]

The immune effector cell-associated syndrome (ICANS) has been described as the second most frequent specific complication following CAR-T cell therapy. The median time to the onset of neurological symptoms is five days after CAR-T infusion. ICANS can be concomitant to cytokine release syndrome but often follows the resolution of the latter. However, 10 % of patients experience delayed onset after 3 weeks of CAR-T cell infusion. The duration of symptoms is usually short, around five days if an early appropriate treatment is given. Symptoms are heterogeneous, ranging from mild symptoms quickly reversible (alterations of consciousness, deterioration in handwriting) to more serious forms with seizures or even a coma. The ICANS severity is currently based on the ASTCT score. The diagnosis of ICANS is clinical but EEG, MRI and lumbar punction can help ruling out alternative diagnoses. The first line treatment consists of high-dose corticosteroids. During the twelfth edition of practice harmonization workshops of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC), a working group focused its work on updating the SFGM-TC recommendations on the management of ICANS. In this review we discuss the management of ICANS and other neurological toxicities in patients undergoing of CAR-T cell therapy. These recommendations apply to commercial CAR-T cells, in order to guide strategies for the management neurological complications associated with this new therapeutic approach.

[Management of cytokine release syndrome and macrophage activation syndrome following CAR-T cell therapy: Guidelines from the SFGM-TC]

The use of chimeric antigen receptor T cells (CAR-T) has increased since their approval in the treatment of several relapsed/refractory B cell malignancies. The management of their specific toxicities, such as cytokine release syndrome (CRS), tends to be better understood and well-defined. During the twelfth edition of practice harmonization workshops of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC), a working group focused its work on the management of patients developing CRS following CAR-T cell therapy. A special chapter has been allocated to macrophage activation syndrome (MAS), a rare but life-threatening complication post-CAR-T. In addition to symptomatic measures and preemptive broad-spectrum antibiotics, immunomodulators such as tocilizumab and corticosteroids remain the corner stone for the treatment of CRS. Tocilizumab/corticosteroids-resistant CRS associated with haemophagocytosis markers (spleen and liver enlargement, hyperferritinaemia>10,000ng/mL, hypofibrinogenemia…) should direct the diagnosis towards an overlapping CRS/MAS. An adapted treatment will be based on high-dose IV anakinra and corticosteroids and chemotherapy with etoposide at late refractory stages. These complications and others delignate the need of close collaboration with an intensive care unit.

Anticancer traits of chimeric antigen receptors (CARs)-Natural Killer (NK) cells as novel approaches for melanoma treatment

Owing to non-responsiveness of a high number of patients to the common melanoma therapies, seeking novel approaches seem as an unmet requirement. Chimeric antigen receptor (CAR) T cells were initially employed against recurrent or refractory B cell malignancies. However, advanced stages or pretreated patients have insufficient T cells (lymphopenia) amount for collection and clinical application. Additionally, this process is time-consuming and logistically cumbersome. Another limitation of this approach is toxicity and cytokine release syndrome (CRS) progress and neurotoxicity syndrome (NS). Natural killer (NK) cells are a versatile component of the innate immunity and have several advantages over T cells in the application for therapies such as availability, unique biological features, safety profile, cost effectiveness and higher tissue residence. Additionally, CAR NK cells do not develop Graft-versus-host disease (GvHD) and are independent of host HLA genotype. Notably, the NK cells number and activity is affected in the tumor microenvironment (TME), paving the way for developing novel approaches by enhancing their maturation and functionality. The CAR NK cells short lifespan is a double edge sword declining toxicity and reducing their persistence. Bispecific and Trispecific Killer Cell Engagers (BiKE and Trike, respectively) are emerging and promising immunotherapies for efficient antibody dependent cell cytotoxicity (ADCC). CAR NK cells have some limitations in terms of expanding and transducing NK cells from donors to achieve clinical response. Clinical trials are in scarcity regarding the CAR NK cell-based cancer therapies. The CAR NK cells short life span following irradiation before infusion limits their efficiency inhibiting their in vivo expansion. The CAR NK cells efficacy enhancement in terms of lifespan TME preparation and stability is a goal for melanoma treatment. Combination therapies using CAR NK cells and chemotherapy can also overcome therapy limitations.

Management of adults and children receiving CAR T-cell therapy: 2021 best practice recommendations of the European Society for Blood and Marrow Transplantation (EBMT) and the Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association (EHA)

BACKGROUND

Several commercial and academic autologous chimeric antigen receptor T-cell (CAR-T) products targeting CD19 have been approved in Europe for relapsed/refractory B-cell acute lymphoblastic leukemia, high-grade B-cell lymphoma and mantle cell lymphoma. Products for other diseases such as multiple myeloma and follicular lymphoma are likely to be approved by the European Medicines Agency in the near future.

DESIGN

The European Society for Blood and Marrow Transplantation (EBMT)-Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association collaborated to draft best practice recommendations based on the current literature to support health care professionals in delivering consistent, high-quality care in this rapidly moving field.

RESULTS

Thirty-six CAR-T experts (medical, nursing, pharmacy/laboratory) assembled to draft recommendations to cover all aspects of CAR-T patient care and supply chain management, from patient selection to long-term follow-up, post-authorisation safety surveillance and regulatory issues.

CONCLUSIONS

We provide practical, clinically relevant recommendations on the use of these high-cost, logistically complex therapies for haematologists/oncologists, nurses and other stakeholders including pharmacists and health sector administrators involved in the delivery of CAR-T in the clinic.

[Prevention and management of infections in patients undergoing CAR T-cell therapy: Recommendations of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Infections occurring after CAR T-cells are a common complication. At the acute phase of treatment following CAR T-cell infusion, the exact incidence of infections is unknown given the overlapping symptoms with cytokine release syndrome. The risk factors for infection include the malignant underlying disease and its multiple treatments, and an immunosuppressive state induced by CAR-T cells themselves and the treatment of their complications. During the twelfth edition of practice harmonization workshops of the Francophone society of bone marrow transplantation and cellular therapy (SFGM-TC), a working group focused its work on the management of post-CAR infectious complications. In this review we discuss anti-infection prophylaxis and vaccination of patients undergoing CAR T-cell therapy as well as a special chapter for the specific case of COVID-19. These recommendations apply to commercial CAR-T cells, in order to guide strategies for the management and prevention of infectious complications associated with this new therapeutic approach.

Current Limitations and Perspectives of Chimeric Antigen Receptor-T-Cells in Acute Myeloid Leukemia

Simple Summary

Acute myeloid leukemia (AML) is the most frequent type of acute leukemia in adults. Allogeneic hematopoietic cell transplantation (allo-HCT) has been the only potentially curative treatment for the majority of patients. The ability of chimeric antigen receptor (CAR)-modified T-cell therapy directed against the CD19 antigen to induce durable remissions in patients with acute lymphoblastic leukemia (ALL) has provided optimism that this novel treatment paradigm can be extrapolated to AML. In this review, we provide an overview of candidate target antigens for CAR-T-cells in AML, an update on recent progress in preclinical and clinical development of investigational CAR-T-cell products, and discuss challenges for the clinical implementation of CAR-T-cell therapy in AML.

Abstract

Adoptive transfer of gene-engineered chimeric antigen receptor (CAR)-T-cells has emerged as a powerful immunotherapy for combating hematologic cancers. Several target antigens that are prevalently expressed on AML cells have undergone evaluation in preclinical CAR-T-cell testing. Attributes of an ‘ideal’ target antigen for CAR-T-cell therapy in AML include high-level expression on leukemic blasts and leukemic stem cells (LSCs), and absence on healthy tissues, normal hematopoietic stem and progenitor cells (HSPCs). In contrast to other blood cancer types, where CAR-T therapies are being similarly studied, only a rather small number of AML patients has received CAR-T-cell treatment in clinical trials, resulting in limited clinical experience for this therapeutic approach in AML. For curative AML treatment, abrogation of bulk blasts and LSCs is mandatory with the need for hematopoietic recovery after CAR-T administration. Herein, we provide a critical review of the current pipeline of candidate target antigens and corresponding CAR-T-cell products in AML, assess challenges for clinical translation and implementation in routine clinical practice, as well as perspectives for overcoming them.

[Complications other than infections, CRS and ICANS following CAR T-cells therapy: Recommendations of the Francophone Society of bone marrow transplantation and cell therapy (SFGM-TC)]

CAR-T cells are an innovative treatment for an increasing number of patients, particularly since the extension of their indication to mantle lymphoma and multiple myeloma. Several complications of CAR T-cell therapy, that were first described as exceptional, have now been reported in series of patients, since its first clinical use in 2011. Among them, cardiac complications, delayed cytopenias, acute and chronic Graft versus Host Disease, and tumoral lysis syndrome are recognized as specific potent complications following CAR T-cells infusion. During the twelfth edition of practice harmonization workshops of the Francophone society of bone marrow transplantation and cellular therapy (SFGM-TC), a working group focused its work on the management of these complications with focuses the epidemiology, the physiopathology and the risk factors of these 4 side effects. Our recommendations apply to commercial CAR-T cells, in order to guide strategies for the management of complications associated with this new therapeutic approach.

[Follow-up logbook of patients receiving CAR T-cell therapy: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

In the attempt to harmonize practices and to create a national CAR T-cells patient follow-up care logbook, the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) worked on the design of a common national care logbook during the eleventh annual workshops of practice harmonization. The purpose of this logbook was to explain the different phases of the treatment with CAR T-cells and to allow useful monitoring for the patient. This logbook can be also helpful for the different healthcare professionals involved in the patient care. This national logbook will provide important information to the patients undergoing CAR T-cell therapy. In addition to the information booklets already in use, the national logbook simplifies patient follow-up by recording various medical appointments and possible adverse events. This work has been based on tools that had already been put in place by different CAR T-cell centers. This national logbook represents a common "base" and is prepared in the form of index cards to be classified using dividers in a binder. Therefore, the national care logbook will be adaptable for local procedures and guidelines of each center.

[Medium-term follow-up of patients treated with chimeric antigen receptor T cells (CAR T cells): Recommendations of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Chimeric antigen receptor (CAR) T cells are a new class of anti-cancer therapy that involves manipulating autologous or allogeneic T cells to express a CAR directed against a membrane antigen. In Europe, tisagenlecleucel (Kymriah™) has marketing authorization for the treatment of relapsed / refractory acute lymphoblastic leukemia (ALL) in children and young adults, in addition to the treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL); the marketing authorization for axicabtagene ciloleucel (Yescarta™) is for the treatment of relapsed / refractory high-grade B-cell lymphoma and for the treatment of primary mediastinal B-cell lymphoma. Both cell products are genetically modified autologous T cells directed against CD19. These recommendations, drawn up by a working group of the Francophone Society of Bone Marrow transplantation and cellular Therapy (SFGM-TC) relate to the management of patients and the supply chain: medium-term complications, in particular cytopenias and B-cell aplasia, nursing and psychological supportive care. In another work, we will address long-term monitoring, post-marketing authorization pharmacovigilance and issues relating to JACIE and regulatory authorities. These recommendations are not prescriptive; their aim is to provide guidelines for the use of this new therapeutic approach. The purpose of this workshop is to outline the organizational aspects of this new therapeutic approach.

Toxicities of Chimeric Antigen Receptor T Cell Therapy in Multiple Myeloma: An Overview of Experience From Clinical Trials, Pathophysiology, and Management Strategies

In the last few years, monoclonal antibodies (mAbs) such as elotuzumab and daratutumab have brought the treatment of multiple myeloma (MM) into the new era of immunotherapy. More recently, chimeric antigen receptor (CAR) modified T cell, a novel cellular immunotherapy, has been developed for treatment of relapsed/refractory (RR) MM, and early phase clinical trials have shown promising efficacy of CAR T cell therapy. Many patients with end stage RRMM regard CAR T cell therapy as their “last chance” and a “hope of cure”. However, severe adverse events (AEs) and even toxic death related to CAR T cell therapy have been observed. The management of AEs related to CAR T cell therapy represents a new challenge, as the pathophysiology is not fully understood and there is still no well-established standard of management. With regard to CAR T cell associated toxicities in MM, in this review, we will provide an overview of experience from clinical trials, pathophysiology, and management strategies.

Actors on the Scene: Immune Cells in the Myeloma Niche

Two mechanisms are involved in the immune escape of cancer cells: the immunoediting of tumor cells and the suppression of the immune system. Both processes have been revealed in multiple myeloma (MM). Complex interactions between tumor plasma cells and the bone marrow (BM) microenvironment contribute to generate an immunosuppressive milieu characterized by high concentration of immunosuppressive factors, loss of effective antigen presentation, effector cell dysfunction, and expansion of immunosuppressive cell populations, such as myeloid-derived suppressor cells, regulatory T cells and T cells expressing checkpoint molecules such as programmed cell death 1. Considering the great immunosuppressive impact of BM myeloma microenvironment, many strategies to overcome it and restore myeloma immunosurveillance have been elaborated. The most successful ones are combined approaches such as checkpoint inhibitors in combination with immunomodulatory drugs, anti-monoclonal antibodies, and proteasome inhibitors as well as chimeric antigen receptor (CAR) T cell therapy. How best to combine anti-MM therapies and what is the optimal timing to treat the patient are important questions to be addressed in future trials. Moreover, intratumor MM heterogeneity suggests the crucial importance of tailored therapies to identify patients who might benefit the most from immunotherapy, reaching deeper and more durable responses.