Mechanisms of immune effector cell-associated neurotoxicity syndrome after CAR-T treatment

Exosomes in review: A new frontier in CAR-T cell therapies

Exosomes are extracellular vehicles that facilitate intra-cellular communication via transport of critical proteins and genetic material. Every exosome is intrinsically reflective of the cell from which it was derived and can even mimic effector functions of their parent cells. In recent years, with the success of CAR-T therapies, there has been growing interest in characterizing exosomes derived from CAR-T cells. CAR exosomes contain the same cytotoxic granules as their parent cells and have demonstrated significant anti-tumor activity in vitro and in animal models. Moreover, infusion of CAR exosomes in animal models did not generate cytokine release syndrome. Conversely, there are also novel bispecific antibodies which target tumor-derived exosomes in hopes of derailing immunosuppressive pathways mediated by exosomes produced from malignant cells. The two most promising examples include (a) BsE CD73 x EpCAM which binds and inhibits exosomal CD73 to suppress production of immunosuppressant adenosine and (b) BsE CD3 x PD-L1 which targets exosomal PD-L1 within the tumor microenvironment to guide cytotoxic T-cells towards tumor cells. As our understanding of exosome biology continues to evolve, opportunities for advances in cellular therapies will grow in tandem.

Leucine-rich α-2 glycoprotein 1 (LRG1) during inflammatory complications after allogeneic stem cell transplantation and CAR-T cell therapy

BACKGROUND

Previous data indicated that the leucine-rich α-2 glycoprotein 1 (LRG1) pathway contributes to vascular dysfunction during cancer growth. Therapeutic targeting of LRG1 normalized tumor vessel dysfunction and enhanced the efficacy of anti-cancer adoptive T cell therapy. A major clinical problem after allogeneic hematopoietic stem cell transplantation (alloHSCT) and after chimeric antigen receptor (CAR) T-cell therapy is the induction of hyperinflammatory side effects, which are typically associated with severe endothelial dysfunction.

METHODS

We investigated LRG1 in preclinical models and in patient samples.

RESULTS

In prospective studies, we found elevated LRG1 serum levels in patients with cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome after CAR-T-cell therapy as well as in patients with acute graft-versus-host disease (aGVHD) after alloHSCT.In preclinical models of aGVHD, we found vasculature-associated LRG1 upregulation as well as LRG1 pathway gene upregulation. The genetic deletion of LRG1 in alloHSCT donors and in alloHSCT recipients led to reduced clinical and histological aGVHD. In line with this, LRG1 deletion led to clinically and histologically reduced disease severity in experimental inflammatory models of colitis (dextran sulfate sodium colitis) and paw edema. LRG1 deletion reduced inflammation-related vascular leakiness, endothelial cell proliferation, and migration.

CONCLUSIONS

The current data support the hypothesis that LRG1 is an attractive therapeutic target after alloHSCT and after CAR-T cell therapy for cancer because of its role in dysfunctional tumor vessels as well as in inflammatory complications.

Mitigation and Management of Common Toxicities Associated with the Administration of CAR-T Therapies in Oncology Patients

Chimeric antigen receptor T-cell (CAR-T) therapies are one of the main approaches among targeted cellular therapies. Despite the potential benefit and durable responses observed in some patients receiving CAR-T therapies, serious and potentially fatal toxicities remain a major challenge. The most common CAR-T-associated toxicities include cytokine release syndrome (CRS), neurotoxicity, cytopenias, and infections. While CRS and neurotoxicity are generally managed with tocilizumab and corticosteroids, respectively, high-grade toxicities can be life-threatening. Close postinfusion monitoring and assessment of clinical laboratory parameters, patient-related and clinical risk factors (e.g., age, tumor burden, comorbidities, baseline laboratory parameters, and underlying abnormalities), and therapy-related risk factors (e.g., CAR-T type, dose, and CAR-T-induced toxicity) are effective strategies to mitigate the toxicities. Clinical laboratory parameters, including various cytokines, have been identified for CRS (interleukin [IL]-1, IL-2, IL-5, IL-6, IL-8, IL-10, C-reactive protein [CRP], interferon [IFN]-γ, ferritin, granulocyte-macrophage colony-stimulating factor [GM-CSF], and monocyte chemoattractant protein-1), neurotoxicity (IL-1, IL-2, IL-6, IL-15, tumor necrosis factor [TNF]-α, GM-CSF, and IFN-γ), cytopenias (IL-2, IL-4, IL-6, IL-10, IFN-γ, ferritin, and CRP), and infections (IL-8, IL-1β, CRP, IFN-γ, and procalcitonin). CAR-T-associated toxicities can be monitored and treated to mitigate the risk to patients. Assessment of alterations in clinical laboratory parameter values that are correlated with CAR-T-associated toxicities may predict development and/or severity of a given toxicity, which can improve patient management strategies and ultimately enable the patients to better tolerate these therapies.

Dose Optimization of Elranatamab to Mitigate the Risk of Cytokine Release Syndrome in Patients with Multiple Myeloma

BACKGROUND

Elranatamab is a BCMA-CD3 bispecific antibody approved for the treatment of relapsed or refractory multiple myeloma. Cytokine release syndrome is one of the most common adverse events associated with bispecific antibodies.

OBJECTIVE

We aimed to determine the optimal elranatamab dosing regimen for mitigating cytokine release syndrome.

PATIENTS AND METHODS

Safety, pharmacokinetics, and exposure-response were analyzed across four clinical studies (MagnetisMM-1, MagnetisMM-2, MagnetisMM-3, and MagnetisMM-9). Different priming regimens evaluated across these studies included a one-step-up dose priming regimen of 44 mg with or without premedication, a two-step-up dose priming regimen of 12 mg on day 1 and 32 mg on day 4 with premedication, and a two-step-up dose priming regimen of 4 mg on day 1 and 20 mg on day 4 with premedication.

RESULTS

The maximum elranatamab serum concentration on day 1 was positively associated with any-grade and grade ≥ 2 cytokine release syndrome. A slower time to maximum serum concentration and a lower dose-normalized maximum serum concentration were observed with subcutaneous versus intravenous administration, supporting subcutaneous dosing to help mitigate cytokine release syndrome.

CONCLUSIONS

Based on the incidence, severity, and predictable profile of cytokine release syndrome, the 12/32-mg priming-dose regimen with premedication was determined to be the optimal regimen before the first full dose of 76 mg on day 8.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT03269136, NCT04798586, NCT04649359, and NCT05014412.

Pharmacovigilance analysis of polatuzumab plus bendamustine and rituximab treatment protocol: identifying comprehensive safety signals using FDA database

Background

The combination of polatuzumab, bendamustine and rituximab (pola+BR) was authorized for the treatment of relapsed or refractory Diffuse large B cell lymphoma (DLBCL). This study used the FDA database to identify safety signals related to the treatment protocol.

Methods

The adverse events (AEs) from 2019Q1 to 2023Q3 were analyzed by calculating the reporting odds ratio. Severe and non-severe cases were compared using either an independent samples t-test or chi-squared (χ2) test. Additionally, a score sheet was employed to prioritize the signals.

Results

In all database, 58 significant signals were detected within 1,597 patients accepting the treatment protocol. Common AEs like neutropenia, thrombocytopenia, and peripheral neuropathy, as well as other AEs like anaemia, sepsis, cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (ICANS) were a major focus. In addtion, 51.7%, 45.6% and 1.7% were sorted into low, moderate and high priority in term of clinical importance, respectively. Unexpected significant signals included intestinal obstruction, epilepsy, deep vein thrombosis, haemorrhage, increased blood lactate dehydrogenase and hypercalcemia.

Conclusion

Our study identified significant AE signals for pola+BR through realworld disproportionality analysis data and analyzed the severity and clinical priority of these signals, which can assist clinicians in managing related AEs.

New approach methodologies to assess wanted and unwanted drugs-induced immunostimulation

This review examines various classes of drugs, focusing on their therapeutic and adverse effects, particularly in relation to immunostimulation. We emphasize the potential of new approach methodologies (NAMs) to study both expected and unexpected immunostimulatory effects. By evaluating the modes of action of different immunostimulatory drugs, we aim to provide insights into effectively assessing unwanted immunostimulatory responses. The review begins by exploring drugs that stimulate the immune system-including immunostimulants, monoclonal antibodies, chemotherapeutics, and nucleic acid-based drugs-to outline NAMs that could be employed to evaluate immunostimulation.

Focusing on exosomes to overcome the existing bottlenecks of CAR-T cell therapy

Since chimeric antigen receptor T (CAR-T) cells were introduced three decades ago, the treatment using these cells has led to outstanding outcomes, and at the moment, CAR-T cell therapy is a well-established mainstay for treating CD19 + malignancies and multiple myeloma. Despite the astonishing results of CAR-T cell therapy in B-cell-derived malignancies, several bottlenecks must be overcome to promote its safety and efficacy and broaden its applicability. These bottlenecks include cumbersome production process, safety concerns of viral vectors, poor efficacy in treating solid tumors, life-threatening side effects, and dysfunctionality of infused CAR-T cells over time. Exosomes are nano-sized vesicles that are secreted by all living cells and play an essential role in cellular crosstalk by bridging between cells. In this review, we discuss how the existing bottlenecks of CAR-T cell therapy can be overcome by focusing on exosomes. First, we delve into the effect of tumor-derived exosomes on the CAR-T cell function and discuss how inhibiting their secretion can enhance the efficacy of CAR-T cell therapy. Afterward, the application of exosomes to the manufacturing of CAR-T cells in a non-viral approach is discussed. We also review the latest advancements in ex vivo activation and cultivation of CAR-T cells using exosomes, as well as the potential of engineered exosomes to in vivo induction or boost the in vivo proliferation of CAR-T cells. Finally, we discuss how CAR-engineered exosomes can be used as a versatile tool for the direct killing of tumor cells or delivering intended therapeutic payloads in a targeted manner.

Into the storm: the imbalance in the yin-yang immune response as the commonality of cytokine storm syndromes

There is a continuous cycle of activation and contraction in the immune response against pathogens and other threats to human health in life. This intrinsic yin-yang of the immune response ensures that inflammatory processes can be appropriately controlled once that threat has been resolved, preventing unnecessary tissue and organ damage. Various factors may contribute to a state of perpetual immune activation, leading to a failure to undergo immune contraction and development of cytokine storm syndromes. A literature review was performed to consider how the trajectory of the immune response in certain individuals leads to cytokine storm, hyperinflammation, and multiorgan damage seen in cytokine storm syndromes. The goal of this review is to evaluate how underlying factors contribute to cytokine storm syndromes, as well as the symptomatology, pathology, and long-term implications of these conditions. Although the recognition of cytokine storm syndromes allows for universal treatment with steroids, this therapy shows limitations for symptom resolution and survival. By identifying cytokine storm syndromes as a continuum of disease, this will allow for a thorough evaluation of disease pathogenesis, consideration of targeted therapies, and eventual restoration of the balance in the yin-yang immune response.

Comparison of the Efficacy and Safety of Axi-Cel and Tisa-Cel Based on Meta-Analysis

This study aimed to analyze the efficacy and safety of chimeric antigen receptor T-cell (CAR-T) therapy for B-cell lymphoma using published literature data. Literature on CAR-T therapy for B-cell lymphoma was collected by searching common databases. The literature was screened, quality assessed, and data extracted according to the inclusion and exclusion criteria. We performed a quantitative meta-analysis of the efficacy and safety of combined literature data. If the data could not be combined, descriptive analysis was performed. The meta-analysis results indicated that compared with tisagenlecleucel (tisa-cel), axicabtagene ciloleucel (axi-cel) had higher objective response rate (ORR) and complete response rate, with odds ratio (OR) of 0.63 for both sides (95% confidence interval [CI], 0.50-0.79) and statistically significant differences. Partial response rate was lower with axi-cel than with tisa-cel, with an OR of 1.02 for tisa-cel versus axi-cel (95% CI, 0.75-1.40) and no statistically significant difference. Compared with tisa-cel, axi-cel had longer progression-free survival and overall survival, with risk ratios of 0.70 (95% CI, 0.62-0.80) and 0.71 (95% CI, 0.61-0.84) for axi-cel and tisa-cel, respectively. Compared with tisa-cel, axi-cel had higher incidence rates of cytokine release syndrome (CRS) and immune effector cell-related neurotoxicity syndrome (ICANS), with ORs of 3.84 (95% CI, 2.10-7.03) and 4.4 (95% CI, 2.81-6.91), respectively. CAR T-cell therapy is an effective treatment option for relapsed/refractory B-cell lymphoma. Axi-cel has better ORR and survival advantages compared with tisa-cel; however, axi-cel has higher incidence rates of CRS and ICANS compared with tisa-cel.

From spear to trident: Upgrading arsenal of CAR-T cells in the treatment of multiple myeloma

Multiple myeloma (MM), marked by abnormal proliferation of plasma cells and production of monoclonal immunoglobulin heavy or light chains in the majority of patients, has traditionally been associated with poor survival, despite improvements achieved in median survival in all age groups since the introduction of novel agents. Survival has significantly improved with the development of new drugs and new treatment options, such as chimeric antigen receptor T-cell therapy (CAR-T), which have shown promise and given new hope in MM therapy. CARs are now classified as first-, second-, and third-generation CARs based on the number of monovalent to trivalent co-stimulatory molecules incorporated into their design. The scope of this review was relatively narrow because it was mainly about a comparison of the literature on the clinical application of CAR-T therapy in MM. Thus, our goal is to provide an overview of the new advances of CAR-T cells in the cure of MM, so in this review we looked at the progress of the clinical use of CAR-T cells in MM to try to provide a reference for their clinical use when managing MM.

Case report: Rapid resolution of grade IV ICANS after first line intrathecal chemotherapy with methotrexate, cytarabine and dexamethasone

Corticosteroid therapy is the mainstay of immune effector cell-associated neurotoxicity syndrome (ICANS) management, although its use has been associated with worse overall survival (OS) and progression-free survival (PFS) after chimeric antigen receptor T-cell (CAR-T cell) therapy. Many options are being investigated for prophylaxis and management. Accumulating evidence supports the use of intrathecal (IT) chemotherapy for the management of high-grade ICANS. Here, we describe a case of a patient with stage IV Primary mediastinal B-cell lymphoma (PMBCL) successfully treated with IT methotrexate, cytarabine, and dexamethasone as first-line therapy for CD19 CAR-T cell-associated grade IV ICANS. The stable and rapid resolution of ICANS to grade 0 allowed us to discontinue systemic corticosteroid use, avoiding CAR-T cells ablation and ensuring preservation of CAR-T cell function. The described patient achieved a complete radiologic and clinical response to CD19 CAR-T cell therapy and remains disease-free after 9 months. This case demonstrates a promising example of how IT chemotherapy could be used as first-line treatment for the management of high-grade ICANS.

Tumor microenvironment and CAR-T cell immunotherapy in B-cell lymphoma

Chimeric receptor antigen T cell (CAR-T cell) therapy has demonstrated effectiveness and therapeutic potential in the immunotherapy of hematological malignancies, representing a promising breakthrough in cancer treatment. Despite the efficacy of CAR-T cell therapy in B-cell lymphoma, response variability, resistance, and side effects remain persistent challenges. The tumor microenvironment (TME) plays an intricate role in CAR-T cell therapy of B-cell lymphoma. The TME is a complex and dynamic environment that includes various cell types, cytokines, and extracellular matrix components, all of which can influence CAR-T cell function and behavior. This review discusses the design principles of CAR-T cells, TME in B-cell lymphoma, and the mechanisms by which TME influences CAR-T cell function. We discuss emerging strategies aimed at modulating the TME, targeting immunosuppressive cells, overcoming inhibitory signaling, and improving CAR-T cell infiltration and persistence. Therefore, these processes enhance the efficacy of CAR-T cell therapy and improve patient outcomes in B-cell lymphoma. Further research will be needed to investigate the molecular and cellular events that occur post-infusion, including changes in TME composition, immune cell interactions, cytokine signaling, and potential resistance mechanisms. Understanding these processes will contribute to the development of more effective CAR-T cell therapies and strategies to mitigate treatment-related toxicities.

Immune Escape in Glioblastoma: Mechanisms of Action and Implications for Immune Checkpoint Inhibitors and CAR T-Cell Therapy

Glioblastoma, the most common primary brain cancer in adults, is characterized by a poor prognosis and resistance to standard treatments. The advent of immunotherapy has revolutionized the treatment of several cancers in recent years but has failed to demonstrate benefit in patients with glioblastoma. Understanding the mechanisms by which glioblastoma exerts tumor-mediated immune suppression in both the tumor microenvironment and the systemic immune landscape is a critical step towards developing effective immunotherapeutic strategies. In this review, we discuss the current understanding of immune escape mechanisms in glioblastoma that compromise the efficacy of immunotherapies, with an emphasis on immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy. In parallel, we review data from preclinical studies that have identified additional therapeutic targets that may enhance overall treatment efficacy in glioblastoma when administered alongside existing immunotherapies.

CAR T-cell-associated neurotoxicity in central nervous system hematologic disease: Is it still a concern?

Chimeric antigen receptor (CAR) T-cell systemic immunotherapy has revolutionized how clinicians treat several refractory and relapsed hematologic malignancies. Due to its peculiar mechanism of action, CAR T-cell-based therapy has enlarged the spectrum of neurological toxicities. CAR T-cell-associated neurotoxicity-initially defined as CAR T-cell-related encephalopathy syndrome (CRES) and currently coined within the acronym ICANS (immune effector cell-associated neurotoxicity syndrome)-is perhaps the most concerning toxicity of CAR T-cell therapy. Importantly, hematologic malignancies (especially lymphoid malignancies) may originate in or spread to the central nervous system (CNS) in the form of parenchymal and/or meningeal disease. Due to the emergence of deadly and neurological adverse events, such as fatal brain edema in some patients included in early CAR T-cell trials, safety concerns for those with CNS primary or secondary infiltration arose and contributed to the routine exclusion of individuals with pre-existing or active CNS involvement from pivotal trials. However, based primarily on the lack of evidence, it remains unknown whether CNS involvement increases the risk and/or severity of CAR T-cell-related neurotoxicity. Given the limited treatment options available for patients once they relapse with CNS involvement, it is of high interest to explore the role of novel clinical strategies including CAR T cells to treat leukemias/lymphomas and myeloma with CNS involvement. The purpose of this review was to summarize currently available neurological safety data of CAR T-cell-based immunotherapy from the clinical trials and real-world experiences in adult patients with CNS disease due to lymphoma, leukemia, or myeloma. Increasing evidence supports that CNS involvement in hematologic disease should no longer be considered per se as an absolute contraindication to CAR T-cell-based therapy. While the incidence may be high, severity does not appear to be impacted significantly by pre-existing CNS status. Close monitoring by trained neurologists is recommended.