Neurologic toxicities following adoptive immunotherapy with BCMA-directed CAR T cells

Novel Neurocognitive Testing Tool for Early Neurotoxicity Detection Following Anti-CD19 and Anti-BCMA Chimeric Antigen Receptor (CAR) T-cell Therapy: A Pilot Study

BACKGROUND

Immune effector cell-associated neurotoxicity syndrome (ICANS) can be a severe, life-threatening toxicity following CAR T-cell therapy. While currently evaluated by the immune effector cell-associated encephalopathy (ICE) score, not all patients have changes in their ICE score and not all signs and symptoms of neurotoxicity are captured.

METHODS

We conducted a prospective, single center cohort pilot study to evaluate a novel, rapid neurocognitive assessment tool (CART-NS) in detecting early, subtle neurotoxicity prior to the onset of ICANS and any deterioration in the ICE score. CART-NS includes 8 abbreviated forms of neurocognitive tests and 2 symptom questionnaires. Following baseline measurements, CART-NS was administered at 8-hour intervals during the first 30 days after CAR T-cell infusion.

RESULTS

Performance on all measures was significantly lower when patients developed Grade 1 or 2 ICANS (P < .05). Performance on Oral Symbol Digit, Stroop, and the Paced Visual Serial Addition Test was lower between Day 0 and +3 in patients who developed ICANS and persisted even after clinical resolution. Early changes in the Stroop test (AUC = 0.857, 95% CI 0.628-1.000) were most predictive of ICANS onset when measured during the first 36 hour following CAR T-cell infusion. Significant elevations in CRP, G-CSF, GM-CSF, IFNγ, IL-10, IL-15, IL-27, and MIG/CXCL-9 were associated with ICANS development.

CONCLUSION

Brief neurocognitive testing can be feasibly applied for the early detection of ICANS after CAR T-cell therapy, predict which patients may go on to develop ICANS in the first 30 days, and overcome limitations of the ICE assessment tool.

CAR-T for multiple myeloma: practice pearls

The CAR-T cell products ciltacabtagene autoleucel and idecabtagene vicleucel have transformed the management of patients with multiple myeloma. Here, we present a practical guide highlighting clinical pearls on the incorporation of CAR-T into clinical practice. Topics addressed include expected outcomes, recommendations for referral timing, bridging therapy, treatment complications, therapeutic sequencing, and management of relapse.

Deep insight into cytokine storm: from pathogenesis to treatment

Cytokine storm (CS) is a severe systemic inflammatory syndrome characterized by the excessive activation of immune cells and a significant increase in circulating levels of cytokines. This pathological process is implicated in the development of life-threatening conditions such as fulminant myocarditis (FM), acute respiratory distress syndrome (ARDS), primary or secondary hemophagocytic lymphohistiocytosis (HLH), cytokine release syndrome (CRS) associated with chimeric antigen receptor-modified T (CAR-T) therapy, and grade III to IV acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation. The significant involvement of the JAK-STAT pathway, Toll-like receptors, neutrophil extracellular traps, NLRP3 inflammasome, and other signaling pathways has been recognized in the pathogenesis of CS. Therapies targeting these pathways have been developed or are currently being investigated. While novel drugs have demonstrated promising therapeutic efficacy in mitigating CS, the overall mortality rate of CS resulting from underlying diseases remains high. In the clinical setting, the management of CS typically necessitates a multidisciplinary team strategy encompassing the removal of abnormal inflammatory or immune system activation, the preservation of vital organ function, the treatment of the underlying disease, and the provision of life supportive therapy. This review provides a comprehensive overview of the key signaling pathways and associated cytokines implicated in CS, elucidates the impact of dysregulated immune cell activation, and delineates the resultant organ injury associated with CS. In addition, we offer insights and current literature on the management of CS in cases of FM, ARDS, systemic inflammatory response syndrome, treatment-induced CRS, HLH, and other related conditions.

Neurotoxic complications of chimeric antigen receptor (CAR) T-cell therapy

Chimeric antigen receptor (CAR) T-cell therapy has revolutionised the treatment of haematological malignancies and has demonstrated efficacy in early trials for solid tumours, neurological and rheumatological autoimmune diseases. However, CAR-T is complicated in some patients by neurotoxicity syndromes including immune-effector cell-associated neurotoxicity syndrome, and the more recently described movement and neurocognitive treatment-emergent adverse events, and tumour inflammation-associated neurotoxicity. These neurotoxic syndromes remain poorly understood and are associated with significant morbidity and mortality. A multidisciplinary approach, including neurologists, haematologists and oncologists, is critical for the diagnosis and management of CAR-T neurotoxicity. This approach will be of increasing importance as the use of CAR-T expands, its applications increase and as novel neurotoxic syndromes emerge.

Long-Term Cognitive Outcomes in Adult Patients Receiving Chimeric Antigen Receptor T-Cell Therapies

BACKGROUND

CAR T-cell therapy (CAR-T) is leading to durable responses in patients with cancer but there is concern that cytokine release syndrome (CRS) and neurotoxicity may impact survivors' cognitive function. We assessed long-term cognitive function in CAR-T recipients and examine factors associated with change in cognition over time.

METHODS

We assessed perceived cognition (Functional Assessment of Cancer Therapy-Cognition) and neurocognitive performance (standardized neuropsychological battery) in adult patients prior to receiving CAR-T and at 6 month follow-up. We examined changes in cognitive outcomes using paired T-tests. We used univariate and multivariate linear regression models to explore whether patient-, disease-, or CAR-T specific factors were associated with change in cognition over time.

RESULTS

We included 106 participants (mean age = 62.7 years, 60.4% male, 56.6% diagnosed with non-Hodgkin´s lymphoma), of whom 70 reported perceived cognition data and 26 underwent neurocognitive performance assessments at both timepoints. There were no changes in perceived cognition (P = .560), overall neurocognitive performance (P = .924), or neurocognitive domains (P´s > .05) from baseline to 6 months post CAR-T. At 6 months, 32.9% reported improved, 47.1% stable, and 20.0% declined perceived cognition relative to baseline. In unadjusted analyses, progressive disease (β = -8.86, P = .012), baseline elevated C-reactive protein (β = -5.60, P = .076) and baseline neurologic comorbidity (β = -11.4, P = .052) were numerically associated with worse perceived cognition over time. In multivariate analyses, only progressive disease was statistically significantly associated with worse perceived cognition (β = -7.32, P = .032) over time.

CONCLUSIONS

We found stable cognition among CAR-T recipients and identified an association of therapy response with change in perceived cognition over time.

Non-ICANS neurological complications after CAR T-cell therapies: recommendations from the EBMT Practice Harmonisation and Guidelines Committee

Neurological complications are an important concern in patients undergoing chimeric antigen receptor (CAR) T-cell therapy. Consensus guidelines inform the management of immune effector cell-associated neurotoxicity syndrome (ICANS). However, these guidelines are based on the early clinical experience with CD19 targeting CAR T cells in B-cell malignancies. In contrast, there are so far no published best practice recommendations on the current management of other non-classical neurological complications, which frequently develop after CAR T-cell infusion and cause clinically significant neurotoxicity. These non-classical neurological complications could be more prevalent because of additional CAR T-cell targets (eg, B cell maturation antigen [BCMA]), widened access, new indications in clinical development (including solid tumours in the CNS), and long-term follow-up. In this Review, the European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonisation and Guidelines Committee provides recommendations on the management of CAR T-cell associated neurological complications that occur after treatment with the licensed CD19 and BCMA CAR T cells, as well as neurological toxicities that are emerging with CAR T cells in clinical trials for solid and haematological cancers. We address movement and neurocognitive toxicity, cranial nerve palsies, tumour inflammation-associated neurotoxicity, stroke, myelopathy, peripheral neuropathy, Guillain-Barré syndrome, fludarabine-associated neurotoxicity, and provide guidance on the psychological support for patients. CNS infections were excluded. The guidelines were developed based on the currently available literature and expert opinion. Recommendations are provided when possible, and areas for further research are highlighted to provide a framework to improve patient care.

Current state and perspectives of CAR T cell therapy in central nervous system diseases

B cell-directed CAR T cell therapy has fundamentally changed the treatment of haematological malignancies, and its scope of application is rapidly expanding to include other diseases such as solid tumours or autoimmune disorders. Therapy-refractoriness remains an important challenge in various inflammatory and non-inflammatory disorders of the CNS. The reasons for therapy failure are diverse and include the limited access current therapies have to the CNS, as well as enormous inter- and intra-individual disease heterogeneity. The tissue-penetrating properties of CAR T cells make them a promising option for overcoming this problem and tackling pathologies directly within the CNS. First application of B cell-directed CAR T cells in neuromyelitis optica spectrum disorder and multiple sclerosis patients has recently revealed promising outcomes, expanding the potential of CAR T cell therapy to encompass CNS diseases. Additionally, the optimization of CAR T cells for the therapy of gliomas is a growing field. As a further prospect, preclinical data reveal the potential benefits of CAR T cell therapy in the treatment of primary neurodegenerative diseases such as Alzheimer's disease. Considering the biotechnological optimizations in the field of T cell engineering, such as extension to target different antigens or variation of the modified T cell subtype, new and promising fields of CAR T cell application are rapidly opening up. These innovations offer the potential to address the complex pathophysiological properties of CNS diseases. To use CAR T cell therapy optimally to treat CNS diseases in the future while minimizing therapy risks, further mechanistic research and prospective controlled trials are needed to assess seriously the disease and patient-specific risk-benefit ratio.

Mechanisms for resistance to BCMA-targeted immunotherapies in multiple myeloma

Multiple myeloma (MM) remains incurable and patients eventually face the relapse/refractory dilemma. B cell maturation antigen (BCMA)-targeted immunotherapeutic approaches have shown great effectiveness in patients with relapsed/refractory MM, mainly including chimeric antigen receptor T cells (CAR-T), bispecific T cell engagers (TCEs), and antibody-drug conjugates (ADCs). However, their impact on long-term survival remains to be determined. Nonetheless, resistance to these novel therapies is still inevitable, raising a challenge that we have never met in both laboratory research and clinical practice. In this scenario, the investigation aiming to enhance and prolong the anti-MM activity of BCMA-targeted therapies has been expanding rapidly. Despite considerable uncertainty in our understanding of the mechanisms for their resistance, they have mainly been attributed to antigen-dependency, T cell-driven factors, and (immune) tumor microenvironment. In this review, we summarize the current understanding of the mechanisms for resistance to BCMA-targeted immunotherapies and discuss potential strategies for overcoming it.

Neurotoxicity and Rare Adverse Events in BCMA-Directed CAR T Cell Therapy: A Comprehensive Analysis of Real-World FAERS Data

Chimeric antigen receptor T (CAR T) cell therapies have emerged as a valuable treatment modality for patients with plasma cell disorders. As the population of patients receiving CAR T therapies grows, the identification and management of associated rare toxicities become increasingly crucial. This study aims to identify safety signals associated with commercial anti-B-cell maturation antigen (BCMA) CAR T therapies using the Food and Drug Administration Adverse Event Reporting System (FAERS). We performed a cross-sectional analysis of the adverse events (AE) reports associated with ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), submitted to FAERS between January 2021 and December 2023. AE frequencies were summarized using descriptive statistics, and safety signals were explored by measuring the reporting odds ratio (ROR) compared to control groups. Among 4,472,782 unique FAERS reports, 1,496 involved BCMA-directed CAR-T therapies. AEs reported more frequently included immune-associated conditions and neurological disorders. Neurotoxicity associated with cilta-cel predominantly manifested as cranial nerve palsies, Parkinson's disease and parkinsonism, and acute and chronic polyneuropathies, while ide-cel neurotoxicity presented as confusion, disorientation, seizures, balance disturbances, and tremors. In cilta-cel reports, other safety signals included Guillain-Barre syndrome (ROR: 17.1, 95% CI 6.1 to 47.5), intracranial hemorrhage and cerebrovascular accidents (ROR: 2.9, 95% CI 1.8 to 4.8), Haemophilus infections (ROR: 34.2, 95% CI 11.8 to 98.9) and cytomegalovirus infections (ROR: 3.9, 95% CI 1.6 to 9.5). For ide-cel, new signals included parkinsonism (ROR: 13.7, 95% CI 5.5 to 34.5), acute and chronic sarcoidosis (ROR: 197.1, 95% CI 32.9 to 1180.1), ventricular arrhythmias, and cardiac arrest (ROR: 3.9, 95% CI 2.1 to 7.3). This analysis provides a comprehensive insight into the safety profiles of the commercial BCMA-directed CAR T therapies, underscoring the importance of vigilant post-marketing surveillance to mitigate potential risks.

CAR T Cells and T-Cell Therapies for Cancer: A Translational Science Review

Importance

Chimeric antigen receptor (CAR) T cells are T lymphocytes that are genetically engineered to express a synthetic receptor that recognizes a tumor cell surface antigen and causes the T cell to kill the tumor cell. CAR T treatments improve overall survival for patients with large B-cell lymphoma and progression-free survival for patients with multiple myeloma.

Observations

Six CAR T-cell products are approved by the US Food and Drug Administration (FDA) for 6 hematologic malignancies: B-cell acute lymphoblastic leukemia, large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, chronic lymphocytic leukemia, and multiple myeloma. Compared with standard chemotherapy followed by stem cell transplant, CAR T cells improved 4-year overall survival in patients with large B-cell lymphoma (54.6% vs 46.0%). Patients with pediatric acute lymphoblastic leukemia achieved durable remission after CAR T-cell therapy. At 3-year follow-up, 48% of patients were alive and relapse free. In people with multiple myeloma treated previously with 1 to 4 types of non-CAR T-cell therapy, CAR T-cell therapy prolonged treatment-free remissions compared with standard treatments (in 1 trial, CAR T-cell therapy was associated with progression-free survival of 13.3 months compared with 4.4 months with standard therapy). CAR T-cell therapy is associated with reversible acute toxicities, such as cytokine release syndrome in approximately 40% to 95% of patients, and neurologic disorders in approximately 15% to 65%. New CAR T-cell therapies in development aim to increase efficacy, decrease adverse effects, and treat other types of cancer. No CAR T-cell therapies are FDA approved for solid tumors, but recently, 2 other T lymphocyte-based treatments gained approvals: 1 for melanoma and 1 for synovial cell sarcoma. Additional cellular therapies have attained responses for certain solid tumors, including pediatric neuroblastoma, synovial cell sarcoma, melanoma, and human papillomavirus-associated cancers. A common adverse effect occurring with these T lymphocyte-based therapies is capillary leak syndrome, which is characterized by fluid retention, pulmonary edema, and kidney dysfunction.

Conclusions and Relevance

CAR T-cell therapy is an FDA-approved therapy that has improved progression-free survival for multiple myeloma, improved overall survival for large B-cell lymphoma, and attained high rates of cancer remission for other hematologic malignancies such as acute lymphoblastic leukemia, follicular lymphoma, and mantle cell lymphoma. Recently approved T lymphocyte-based therapies demonstrated the potential for improved outcomes in solid tumor malignancies.

CAR T-cell therapy to treat multiple myeloma: current state and future directions

Chimeric antigen receptor (CAR) T-cell therapy represents a transformative advancement in treating relapsed or refractory multiple myeloma (MM) in both early- and late-line settings. MM, a plasma cell malignancy, traditionally requires ongoing complex drug regimens, posing significant burdens on patients. In contrast, CAR T-cell therapy offers a one-time treatment option without the need for continuous maintenance therapy. CAR T-cell therapy leverages engineered T-cells to target specific antigens on tumor cells, leading to their elimination. Current approved therapies target B-cell maturation antigen (BCMA); new targets are under investigation, such as G-protein-coupled receptor class C group 5 member D (GPRC5D). Despite its efficacy, CAR T-cell therapy is associated with serious toxicities such as cytokine release syndrome (CRS) and immune-effector cell-associated neurotoxicity syndrome (ICANS), necessitating careful management. The review will provide an overview of the design and manufacturing of CAR T-cells and current FDA indications, as well as challenges and future directions of CAR-T therapy for MM treatment.

New horizons in our understanding of precursor multiple myeloma and early interception

Multiple myeloma is an incurable plasma cell malignancy that evolves over decades through the selection and malignant transformation of monoclonal plasma cells. The evolution from precursor states to symptomatic disease is characterized by an increasing complexity of genomic alterations within the plasma cells and a remodelling of the microenvironment towards an immunosuppressive state. Notably, in patients with advanced disease, similar mechanisms of tumour escape and immune dysfunction mediate resistance to modern T cell-based therapies, such as T cell-engaging bispecific antibodies and chimeric antigen receptor (CAR)-T cells. Thus, an increasing number of clinical trials are assessing the efficiency and safety of these therapies in individuals with newly diagnosed multiple myeloma and high-risk smoldering multiple myeloma. In this Review, we summarize the current knowledge about tumour intrinsic and extrinsic processes underlying progression from precursor states to symptomatic myeloma and discuss the rationale for early interception including the use of T cell-redirecting therapies.

Chimeric antigen receptor-T-cell therapies going viral: latent and incidental viral infections

PURPOSE OF REVIEW

Infections are the leading cause of non-relapse mortality following chimeric antigen receptor (CAR)-T-cell therapy, with viral infections being frequent both in the early and late phases post-infusion. We review the epidemiology of viral infections and discuss critical approaches to prevention and management strategies in this setting.

RECENT FINDINGS

Herpesviruses dominate the early period. herpes simplex virus and varicella zoster virus infections are rare due to widespread antiviral prophylaxis, but cytomegalovirus (CMV) reactivation is increasingly observed, particularly in high-risk groups including B cell maturation antigen (BCMA)-CAR-T-cell therapy recipients and patients receiving corticosteroids. While CMV end-organ disease is rare, CMV is associated with increased mortality, emphasizing the need to evaluate the broader impact of CMV on long-term hematological, infection, and survival outcomes. Human herpesvirus-6 (HHV-6) has also emerged as a concern, with its diagnosis complicated by overlapping symptoms with neurotoxicity, underscoring the importance of considering viral encephalitis in differential diagnoses. Respiratory viruses are the most common late infections with a higher incidence after BCMA CAR-T-cell therapy. Vaccination remains a critical preventive measure against respiratory viruses but may be less immunogenic following CAR-T-cell therapy. The optimal timing, type of vaccine, and dosing schedule require further investigation.

SUMMARY

A better understanding of viral epidemiology and preventive trials are needed to improve infection prevention practices and outcomes following CAR-T-cell therapies.

CAR-T cell therapy in Multiple Myeloma: current status and future challenges

The treatment of multiple myeloma has changed dramatically in recent years, with huge strides forward made in the field. Chimeric antigen receptor T-cell therapy targeting the B cell maturation antigen (BCMA) is now widely approved in relapsed refractory patients and is moving into earlier treatment lines. In this review, we discuss the evidence underpinning current regulatory approvals and consider mechanisms through which CAR-T cell efficacy could be improved. These include tackling BCMA-loss, harnessing the immunosuppressive tumour microenvironment, manufacturing concerns including the potential role of other cellular sources, safety issues such as cytokine release syndrome and neurotoxicity, and optimal patient selection.

Cellular Therapies for Multiple Myeloma: Engineering Hope

Multiple myeloma (MM) treatment remains challenging due to its relapsed/refractory disease course as well as intra- and inter-patient heterogeneity. Cellular immunotherapies, especially chimeric antigen receptor (CAR)-T cells targeting B cell maturation antigen (BCMA), mark a major breakthrough, achieving long-lasting remissions and instilling hope for a potential cure. While ongoing clinical trials are increasingly driving approved cellular products towards earlier lines of therapy, novel targets as well as advanced approaches employing natural killer (NK) cells or dendritic cell (DC) vaccines are currently under investigation. Treatment resistance, driven by tumor-intrinsic factors such as antigen escape and the intricate dynamics of the tumor microenvironment (TME), along with emerging side effects such as movement and neurocognitive treatment-emergent adverse events (MNTs), are the major limitations of approved cellular therapies. To improve efficacy and overcome resistance, cutting-edge research is exploring strategies to target the microenvironment as well as synergistic combinatorial approaches. Recent advances in CAR-T cell production involve shortened manufacturing protocols and "off-the-shelf" CAR-T cells, aiming at decreasing socioeconomic barriers and thereby increasing patient access to this potential lifesaving therapy. In this review, we provide an extensive overview of the evolving field of cellular therapies for MM, underlining the potential to achieve long-lasting responses.

Survivorship in Chimeric Antigen Receptor T-Cell Therapy Recipients: Infections, Secondary Malignancies, and Non-Relapse Mortality

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy has significantly advanced the treatment of hematologic malignancies, offering curative potential for patients with relapsed or refractory disease. However, the long-term survivorship of these patients is marked by unique challenges, particularly immune deficits and infectious complications, second primary malignancies (SPMs), and non-relapse mortality (NRM). Understanding and addressing these risks is paramount to improving patient outcomes and quality of life.

SUMMARY

This review explores the incidence and risk factors for NRM and long-term complications following CAR T-cell therapy. Infections are the leading cause of NRM, accounting for over 50% of cases, driven by neutropenia, hypogammaglobulinemia, and impaired cellular immunity. SPMs, including secondary myeloid and T-cell malignancies, are increasingly recognized, prompting the FDA to issue a black box warning, although their direct link to CAR T cells remains disputed. While CAR T-cell-specific toxicities like cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome contribute to morbidity, they represent only a minority of NRM cases. The management of these complications is critical as CAR T-cell therapy is being evaluated for broader use, including in earlier treatment lines and for non-malignant conditions like autoimmune diseases.

KEY MESSAGES

CAR T-cell therapy has revolutionized cancer treatment, but survivorship is complicated by infections, SPMs, and ultimately endangered by NRM. Prophylactic strategies, close monitoring, and toxicity management strategies are key to improving long-term outcomes.

Second Primary Malignancies after CAR T-Cell Therapy: A Systematic Review and Meta-analysis of 5,517 Lymphoma and Myeloma Patients

PURPOSE

Chimeric antigen receptor (CAR) T-cell therapy is a potent immunotherapy for hematologic malignancies, but patients can develop long-term adverse events, including second primary malignancies (SPM) that impact morbidity and mortality. To delineate the frequency and subtypes of SPMs following CAR-T in lymphoma and myeloma, we performed a systematic review and meta-analysis.

EXPERIMENTAL DESIGN

A literature search was conducted in the MEDLINE, Embase, and Cochrane CENTRAL databases. Following the extraction of SPM cases and assignment of malignant origin, we analyzed SPM point estimates using random effects models.

RESULTS

We identified 326 SPMs across 5,517 patients from 18 clinical trials and 7 real-world studies. With a median follow-up of 21.7 months, the overall SPM point estimate was 6.0% (95% confidence interval, 4.8%-7.4%). SPM estimates were associated with treatment setting (clinical trials > real-world studies), duration of follow-up, and number of prior treatment lines, which were each confirmed as independent study-level risk factors of SPM in a meta-regression model. A subgroup meta-analysis of the four trials that randomized CAR-T versus standard-of-care revealed a similar risk of SPM with either treatment strategy (P = 0.92). In a distribution analysis of SPM subtypes, hematologic malignancies were the most common entity (37%), followed by solid tumors (27%) and non-melanoma skin cancers (16%). T-cell malignancies represented a small minority of events (1.5%). We noted disease- and product-specific variations in SPM distribution.

CONCLUSIONS

These data raise awareness of SPM as a clinically relevant long-term adverse event in patients receiving CAR T-cell therapy. However, our findings do not indicate that SPM frequency is higher with CAR-T versus previous standard-of-care strategies.

Quadriparesis and paraparesis following chimeric antigen receptor T-cell therapy in children and adolescents

ABSTRACT

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common but potentially severe adverse event associated with chimeric antigen receptor T-cell (CART) therapy, characterized by the development of acute neurologic symptoms following CART infusion. ICANS encompasses a wide clinical spectrum typified by mild to severe encephalopathy, seizures, and/or cerebral edema. As more patients have been treated with CART, new ICANS phenomenology has emerged. We present the clinical course of 5 children who developed acute onset of quadriparesis or paraparesis associated with abnormal brain and/or spine neuroimaging after infusion of CD19- or CD22-directed CART, adverse events not previously reported in children. Orthogonal data from autopsy studies, cerebrospinal fluid (CSF) flow cytometry, and CSF proteomics/cytokine profiling demonstrated chronic white matter destruction, but a notable lack of inflammatory pathologic changes and cell populations. Instead, children with quadriparesis or paraparesis post-CART therapy had lower levels of proinflammatory cytokines, such as interferon gamma, CCL17, CCL23, and CXCL10, than those who did not develop quadriparesis or paraparesis. Taken together, these findings imply a noninflammatory source of this newly described ICANS phenomenon in children. The pathophysiology of some neurologic symptoms following CART may therefore have a more complex etiology than exclusive T-cell activation and excessive cytokine production.

The first case of multiple myeloma treated with ASCT followed by Anti-BCMA CAR-T cells using retrovirus vector: A case report

Chimeric antigen receptor T (CAR-T)-cell therapy targeting B-cell maturation antigen (BCMA) is currently one of the promising treatment methods for relapsed/refractory multiple myeloma (MM). Herein, this study is a case report on a 41-year-old male patient with MM. Unfortunately, he still developed multidrug-resistant, refractory, and bone marrow suppression after receiving multiline high-intensity chemotherapy. After a detailed evaluation, the physician recommended autologous hematopoietic stem cell transplantation (ASCT) support, followed by sequential immunotherapy with autologous anti- BCMA CAR-T cells. The CAR-T product is a novel anti-BCMA CAR-T based on Retrovirus vectors (RV). It was worth noting that the patient achieved VGPR (very good partial remission) one month after infusion of anti-BCMA CAR-T cells. Recent tests have found that the M protein was no longer detectable and the patient has achieved CR (complete response). Although grade 3 cytokine release syndrome (CRS) appeared, the symptom was well controlled and immune effector cell-associated neurotoxicity syndrome (ICANS) did not occur. This was the first case report of RV prepared anti-BCMA CAR-T cells combined with ASCT for the treatment of MM patient in clinical practice, indicating that the RV-based anti-BCMA-CAR-T cells with ASCT have excellent therapeutic efficacy and high safety in triple-refractory MM patients.

A systematic review and meta-analysis of nonrelapse mortality after CAR T cell therapy

Although chimeric antigen receptor (CAR) T cell therapy represents a transformative immunotherapy, it is also associated with distinct toxicities that contribute to morbidity and mortality. In this systematic review and meta-analysis, we searched MEDLINE, Embase and CINAHL (Cochrane) for reports of nonrelapse mortality (NRM) after CAR T cell therapy in lymphoma and multiple myeloma up to March 2024. After extraction of causes and numbers of death, we analyzed NRM point estimates using random-effect models. We identified 7,604 patients across 18 clinical trials and 28 real-world studies. NRM point estimates varied across disease entities and were highest in patients with mantle-cell lymphoma (10.6%), followed by multiple myeloma (8.0%), large B cell lymphoma (6.1%) and indolent lymphoma (5.7%). Entity-specific meta-regression models for large B cell lymphoma and multiple myeloma revealed that axicabtagene ciloleucel and ciltacabtagene autoleucel were independently associated with increased NRM point estimates, respectively. Of 574 reported nonrelapse deaths, over half were attributed to infections (50.9%), followed by other malignancies (7.8%) and cardiovascular/respiratory events (7.3%). Conversely, the CAR T cell-specific side effects, immune effector cell-associated neurotoxicity syndrome/neurotoxicity, cytokine release syndrome and hemophagocytic lymphohistiocytosis, represented only a minority of nonrelapse deaths (cumulatively 11.5%). Our findings underline the critical importance of infectious complications after CAR T cell therapy and support the comprehensive reporting of NRM, including specific causes and long-term outcomes.

Timing of Toxicities and Non-Relapse Mortality Following CAR T Therapy in Myeloma

BCMA-directed chimeric antigen receptor T-cell (CAR T) therapies, including idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel), have transformed the treatment landscape for relapsed-refractory multiple myeloma (RRMM), offering remarkable efficacy with hallmark toxicity risks of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The FDA mandates a 4-week monitoring period at the treatment center as part of a Risk Evaluation and Mitigation Strategy (REMS) to monitor and manage these toxicities, which, while prudent, may add unnecessary challenges related to access and socioeconomic disparities. We sought to assess CRS and ICANS onset and duration, as well as causes of non-relapse mortality (NRM) in real-world BCMA CAR T recipients in order to better inform future changes to the monitoring guidelines for CAR T recipients. This is a retrospective study across four academic centers that examined 129 ide-cel and cilta-cel recipients that received CAR T cell infusions from May 2021 to June 2023. Infusion and toxicities were managed per institutional guidelines in accordance with previously published guidelines. While differences were noted in the incidence and duration of CRS/ ICANS between ide-cel and cilta-cel, late-onset CRS and ICANS were rare after 2 weeks following infusion (0% and 1.6%, respectively). NRM was driven by hemophagocytic lymphohistiocytosis and infections in the early follow-up period (1.1% until Day 29), then by infections through three months post-infusion (1.2%). Our findings suggest that 25% of patients had to relocate for 4 weeks due to distance from the treatment center. With the low risk of CRS and ICANS after 2 weeks, a flexible shorter monitoring period may be reasonable, emphasizing collaboration with referring oncologists to improve NRM.

Parkinsonism Following Chimeric Antigen Receptor T Cell Therapy

This case report describes a 67-year-old woman who had received adoptive immunotherapy with chimeric antigen receptor T cells for multiple myeloma and was experiencing parkinsonism-like symptoms.

Bispecific antibodies and autologous chimeric antigen receptor T cell therapies for treatment of hematological malignancies

In recent years, the therapeutic landscape for hematological malignancies has markedly advanced, particularly since the inaugural approval of autologous chimeric antigen receptor T cell (CAR-T) therapy in 2017 for relapsed/refractory acute lymphoblastic leukemia (ALL). Autologous CAR-T therapy involves the genetic modification of a patient's T cells to specifically identify and attack cancer cells, while bispecific antibodies (BsAbs) function by binding to both cancer cells and immune cells simultaneously, thereby triggering an immune response against the tumor. The subsequent approval of various CAR-T therapies and BsAbs have revolutionized the treatment of multiple hematological malignancies, highlighting high response rates and a subset of patients achieving prolonged disease control. This review explores the mechanisms underlying autologous CAR-T therapies and BsAbs, focusing on their clinical application in multiple myeloma, ALL, and non-Hodgkin lymphoma. We provide comprehensive insights into their individual efficacy, limitations concerning broad application, and the potential of combination therapies. These upcoming strategies aim to propel the field forward, paving the way for safer and more effective therapeutic interventions in hematological malignancies.

Comparing the Differences in Adverse Events among Chimeric Antigen Receptor T-Cell Therapies: A Real-World Pharmacovigilance Study

In this study, we compared the similarities and differences in adverse events (AEs) among CAR T-cell products through signal mining via the FDA Adverse Event Reporting System (FAERS) and identified unknown AEs to provide a reference for safe clinical medication. Data from the FAERS database spanning from the fourth quarter of 2017 to the first quarter of 2024 were extracted. Signals were identified using the reporting odds ratio (ROR) method and the Medicines and Healthcare Products Regulatory Agency (MHRA) method. A total of 11,386 AE reports related to six CAR T-cell products were selected. The top three categories of AEs reported were nervous system disorders, immune system disorders, and general disorders and administration site conditions. However, there were variations in the AE spectra among the different CAR T-cell products. The BCMA-targeting drugs idecabtagene vicleucel (Ide-cel) and ciltacabtagene autoleucel (Cilta-cel) were found to be associated with parkinsonism, which were not observed in CD19-targeting drugs. Tisagenlecleucel (Tisa-cel) and axicabtagene ciloleucel (Axi-cel) exhibited cerebrovascular accident-related AEs, graft versus host disease, and abnormal coagulation indices. Cilta-cel was associated with cerebral hemorrhage, intracranial hemorrhage, cranial nerve disorder, and facial nerve disorder. Cardiopulmonary toxicity, including hypoxia, tachypnoea, cardiorenal syndrome, and hypotension, exhibited strong signal intensities and considerable overlap with CRS. The number of positive signals for cardiopulmonary toxicity associated with drugs targeting CD-19 is greater. Clinicians should assess patients prior to medication and closely monitor their vital signs, mental status, and laboratory parameters during treatment.

Just scratching the surface: novel treatment approaches for multiple myeloma targeting cell membrane proteins

A better understanding of the roles of the adaptive and innate immune systems in the oncogenesis of cancers including multiple myeloma (MM) has led to the development of novel immune-based therapies. B cell maturation antigen (BCMA), G protein-coupled receptor family C group 5 member D (GPRC5D) and Fc receptor-like protein 5 (FcRL5, also known as FcRH5) are cell-surface transmembrane proteins expressed by plasma cells, and have been identified as prominent immunotherapeutic targets in MM, with promising activity demonstrated in patients with heavily pretreated relapsed and/or refractory disease. Indeed, since 2020, antibody-drug conjugates, bispecific T cell engagers and autologous chimeric antigen receptor T cells targeting BCMA or GPRC5D have been approved for the treatment of relapsed and/or refractory MM. However, responses to these therapies are not universal, and acquired resistance invariably occurs. In this Review, we discuss the various immunotherapeutic approaches targeting BCMA, GPRC5D and FcRL5 that are currently either available or in clinical development for patients with MM. We also review the mechanisms underlying resistance to such therapies, and discuss potential strategies to overcome these mechanisms and improve patient outcomes.

Riding the storm: managing cytokine-related toxicities in CAR-T cell therapy

The advent of chimeric antigen receptor T cells (CAR-T) has been a paradigm shift in cancer immunotherapeutics, with remarkable outcomes reported for a growing catalog of malignancies. While CAR-T are highly effective in multiple diseases, salvaging patients who were considered incurable, they have unique toxicities which can be life-threatening. Understanding the biology and risk factors for these toxicities has led to targeted treatment approaches which can mitigate them successfully. The three toxicities of particular interest are cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and immune effector cell-associated hemophagocytic lymphohistiocytosis (HLH)-like syndrome (IEC-HS). Each of these is characterized by cytokine storm and hyperinflammation; however, they differ mechanistically with regard to the cytokines and immune cells that drive the pathophysiology. We summarize the current state of the field of CAR-T-associated toxicities, focusing on underlying biology and how this informs toxicity management and prevention. We also highlight several emerging agents showing promise in preclinical models and the clinic. Many of these established and emerging agents do not appear to impact the anti-tumor function of CAR-T, opening the door to additional and wider CAR-T applications.

Current understanding and management of CAR T cell-associated toxicities

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of several haematological malignancies and is being investigated in patients with various solid tumours. Characteristic CAR T cell-associated toxicities such as cytokine-release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are now well-recognized, and improved supportive care and management with immunosuppressive agents has made CAR T cell therapy safer and more feasible than it was when the first regulatory approvals of such treatments were granted in 2017. The increasing clinical experience with these therapies has also improved recognition of previously less well-defined toxicities, including movement disorders, immune effector cell-associated haematotoxicity (ICAHT) and immune effector cell-associated haemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), as well as the substantial risk of infection in patients with persistent CAR T cell-induced B cell aplasia and hypogammaglobulinaemia. A more diverse selection of immunosuppressive and supportive-care pharmacotherapies is now being utilized for toxicity management, yet no universal algorithm for their application exists. As CAR T cell products targeting new antigens are developed, additional toxicities involving damage to non-malignant tissues expressing the target antigen are a potential hurdle. Continued prospective evaluation of toxicity management strategies and the design of less-toxic CAR T cell products are both crucial for ongoing success in this field. In this Review, we discuss the evolving understanding and clinical management of CAR T cell-associated toxicities.

Current progress of CAR-T-cell therapy for patients with multiple myeloma

Currently available chimeric antigen receptor (CAR)-engineered T-cell therapies targeting B-cell maturation antigen (BCMA), namely, idecabtagene vicleucel and ciltacabtagene autoleucel, have shown marked efficacy against relapsed and refractory multiple myeloma. However, further improvement in CAR-T-cell function is warranted as most patients treated with these products eventually relapse due to various mechanisms such as antigen loss and T-cell dysfunction or disappearance. Strategies for improving CAR-T-cell function include targeting of dual antigens, enhancing cell longevity through genetic modification, and eliminating the immunosuppressive tumor microenvironment. Serious side effects can also occur after CAR-T-cell infusions. Although understanding of the molecular pathogenesis of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome is growing, the unique movement disorder caused by BCMA-targeted therapy is less understood, and its molecular mechanisms must be further elucidated to establish better management strategies. In this article, we will review the current status of BCMA-targeting CAR-T-cell therapy. We will also highlight progress in the development of CAR-T cells targeting other antigens, as well as universal allogeneic CAR-T cells and bispecific antibodies.

Small molecule-regulated switches to provide functional control of CAR T cells within the patient

INTRODUCTION

CAR T cells have generated great excitement due to their remarkable clinical response rates in selected hematologic malignancies. However, these engineered immune cells are living drugs which are hard to control after administration.

AREAS COVERED

We discuss small molecule-regulated switch systems which can potentially be used to control CAR T cell function within the patient, as well as the most important obstacles in the CAR T cell field, which might be overcome with those switch systems.

EXPERT OPINION

There is an urgent need to develop advanced switch systems. Once available, we expect that they will open up new avenues for future CAR T cell generations.

[Immunotherapy in multiple myeloma]

Patients with multiple myeloma who present with refractory disease or relapse after receiving the main classes of available drugs -immunomodulators, proteasome inhibitors and antibodies against CD38- do not have satisfactory therapeutic alternatives. New treatments based on the redirection of T lymphocytes to act directly against tumor cells, such as bispecific antibodies and T cells with chimeric antigen receptors, are changing this scenario. The published information confirms unprecedented antitumor activity of these agents in patients with refractory myeloma and they will certainly represent the backbone of the treatment of these patients in the immediate future. However, these therapies also present specific characteristics and medium or long-term toxicities that pose new healthcare challenges. In this review, we address the current results and future challenges of the administration of these treatments in patients with relapsed or refractory multiple myeloma.

Beyond BCMA: the next wave of CAR T cell therapy in multiple myeloma

Chimeric antigen receptor (CAR) T cell therapy has transformed the treatment landscape of relapsed/refractory multiple myeloma. The current Food and Drug Administration approved CAR T cell therapies idecabtagene vicleucel and ciltacabtagene autoleucel both target B cell maturation antigen (BCMA), which is expressed on the surface of malignant plasma cells. Despite deep initial responses in most patients, relapse after anti-BCMA CAR T cell therapy is common. Investigations of acquired resistance to anti-BCMA CAR T cell therapy are underway. Meanwhile, other viable antigenic targets are being pursued, including G protein-coupled receptor class C group 5 member D (GPRC5D), signaling lymphocytic activation molecule family member 7 (SLAMF7), and CD38, among others. CAR T cells targeting these antigens, alone or in combination with anti-BCMA approaches, appear to be highly promising as they move from preclinical studies to early phase clinical trials. This review summarizes the current data with novel CAR T cell targets beyond BCMA that have the potential to enter the treatment landscape in the near future.

Optimizing the CAR T-Cell Therapy Experience in Multiple Myeloma: Clinical Pearls From an Expert Roundtable

Chimeric antigen receptor T-cell (CAR-T) therapies offer substantial advancement in the treatment of multiple myeloma (MM). However, the CAR-T therapy process involves complex decision-making that is informed by many variables. This review aims to provide an overview of the patient selection and administration process for CAR-T therapy for MM from the perspective of experienced healthcare providers (HCPs), including considerations for each step in the CAR-T therapy process. Referring HCPs should initiate conversations with HCPs at CAR-T capable centers earlier in the treatment journey, even before patients are eligible for CAR-T therapy, particularly for patients from underserved populations and patients with high-risk disease, to ensure adequate time for logistical planning and patient education. Patient selection for CAR-T therapy may be guided by factors such as performance status, rate of disease progression, and logistical considerations. Some anticancer therapies may affect T-cell fitness and therefore impact CAR-T manufacturing and patient outcomes; however, additional research is needed to confirm this in MM. Bridging therapies should be tailored to the needs of the patient and ideally halted 1 week or longer before CAR-T infusion, contingent upon the agent(s) used. Lymphodepletion regimens may need to be modified for patients with renal insufficiency. Collaboration with HCPs at both the treating and referring centers is important to optimize coordinated care of patients. Collaboration with and guidance from experienced HCPs throughout patient selection, referral, and CAR-T administration is instrumental in optimizing patient outcomes as access to CAR-T therapies expands.

Optimization of a flow cytometry test for routine monitoring of B cell maturation antigen targeted CAR in peripheral blood

Chimeric antigen receptor (CAR) modified T cell therapies targeting BCMA have displayed impressive activity in the treatment of multiple myeloma. There are currently two FDA licensed products, ciltacabtagene autoleucel and idecabtagene vicleucel, for treating relapsed and refractory disease. Although correlative analyses performed by product manufacturers have been reported in clinical trials, there are limited options for reliable BCMA CAR T detection assays for physicians and researchers looking to explore it as a biomarker for clinical outcome. Given the known association of CAR T cell expansion kinetics with toxicity and response, being able to quantify BCMA CAR T cells routinely and accurately in the blood of patients can serve as a valuable asset. Here, we optimized an accurate and sensitive flow cytometry test using a PE-conjugated soluble BCMA protein, with a lower limit of quantitation of 0.19% of CD3+ T cells, suitable for use as a routine assay for monitoring the frequency of BCMA CAR T cells in the blood of patients receiving either ciltacabtagene autoleucel or idecabtagene vicleucel.

The preclinical discovery and clinical development of ciltacabtagene autoleucel (Cilta-cel) for the treatment of multiple myeloma

INTRODUCTION

Despite remarkable therapeutic advances over the last two decades, which have resulted in dramatic improvements in patient survival, multiple myeloma (MM) is still considered an incurable disease. Therefore, there is a high need for new treatment strategies. Genetically engineered/redirected chimeric antigen receptor (CAR) T cells may represent the most compelling modality of immunotherapy for cancer treatment in general, and MM in particular. Indeed, unprecedented response rates have led to the recent approvals of the first two BCMA-targeted CAR T cell products idecabtagene-vicleucel ('Ide-cel') and ciltacabtagene-autoleucel ('Cilta-Cel') for the treatment of heavily pretreated MM patients. In addition, both are emerging as a new standard-of-care also in earlier lines of therapy.

AREAS COVERED

This article briefly reviews the history of the preclinical development of CAR T cells, with a particular focus on Cilta-cel. Moreover, it summarizes the newest clinical data on Cilta-cel and discusses strategies to further improve its activity and reduce its toxicity.

EXPERT OPINION

Modern next-generation immunotherapy is continuously transforming the MM treatment landscape. Despite several caveats of CAR T cell therapy, including its toxicity, costs, and limited access, prolonged disease-free survival and potential cure of MM are finally within reach.

Rapid anti-myeloma activity by T cells expressing an anti-BCMA CAR with a human heavy-chain-only antigen-binding domain

Multiple myeloma (MM) is a rarely curable malignancy of plasma cells. MM expresses B cell maturation antigen (BCMA). We developed a fully human anti-BCMA chimeric antigen receptor (CAR) with a heavy-chain-only antigen-recognition domain, a 4-1BB domain, and a CD3ζ domain. The CAR was designated FHVH33-CD8BBZ. We conducted the first-in-humans clinical trial of T cells expressing FHVH33-CD8BBZ (FHVH-T). Twenty-five patients with relapsed MM were treated. The stringent complete response rate (sCR) was 52%. Median progression-free survival (PFS) was 78 weeks. Of 24 evaluable patients, 6 (25%) had a maximum cytokine-release syndrome (CRS) grade of 3; no patients had CRS of greater than grade 3. Most anti-MM activity occurred within 2-4 weeks of FHVH-T infusion as shown by decreases in the rapidly changing MM markers serum free light chains, urine light chains, and bone marrow plasma cells. Blood CAR+ cell levels peaked during the time that MM elimination was occurring, between 7 and 15 days after FHVH-T infusion. C-C chemokine receptor type 7 (CCR7) expression on infusion CD4+ FHVH-T correlated with peak blood FHVH-T levels. Single-cell RNA sequencing revealed a shift toward more differentiated FHVH-T after infusion. Anti-CAR antibody responses were detected in 4 of 12 patients assessed. FHVH-T has powerful, rapid, and durable anti-MM activity.