First report of CART treatment in AL amyloidosis and relapsed/refractory multiple myeloma

Changing lanes: extending CAR T-cell therapy to high-risk plasma cell dyscrasias

Chimeric antigen receptor (CAR) cellular therapies have advanced outcomes in challenging hematologic malignancies like leukemia, lymphoma, and multiple myeloma. Plasma cell-directed CAR T-cell therapies have been particularly beneficial in multiple myeloma, suggesting that these agents may have a role in other challenging plasma cell disorders such as systemic AL amyloidosis and plasma cell leukemia. AL amyloidosis is a monoclonal plasma cell disorder resulting in the deposition of protein fibrils that compromise end-organ function. Delays in diagnosis can result in end-organ dysfunction and organ failure, making designing and completing treatment difficult. Plasma cell leukemia (PCL) is a rare and highly challenging malignancy with dismal survival outcomes despite aggressive therapy. Both diagnoses are currently treated with regimens borrowed from myeloma: a combination of novel agents and chemotherapy induction, then autologous stem cell transplantation (ASCT), with the current practice trending towards consolidation and maintenance. Unfortunately, only 20% of AL amyloidosis patients are transplant-eligible at diagnosis. Those transplant-ineligible (TIE) patients are treated with combination induction chemotherapy, which may be limited by worsening disease-related end-organ dysfunction. Plasma cell leukemia patients are still very likely to relapse after this intensive and prolonged therapy. Despite the promise of a shorter course of therapy, CAR T-cell therapies directed against plasma cells have not been rigorously investigated in patients with AL amyloidosis or PCL; most trials of MM have excluded these patients. Herein, we describe current treatment paradigms for AL amyloidosis and PCL and review the evidence for CAR T-cell therapies in these challenging plasma cell disorders. Further investigation into CAR T-cell therapies for plasma cell disorders other than multiple myeloma is warranted.

Update on B-cell maturation antigen-directed therapies in AL amyloidosis

Systemic light chain (AL) amyloidosis is a rare clonal plasma cell disorder characterized by the production of amyloidogenic immunoglobulin light chains, which causes the formation and deposition of amyloid fibrils, leading to multi-organ dysfunction. Current treatment is directed at the underlying plasma cell clone to achieve a profound reduction in the monoclonal free light chain production. The standard-of-care first-line therapy is a combination of daratumumab, cyclophosphamide, bortezomib and dexamethasone (D-VCd regimen), resulting in high rates of haematological and organ responses. However, AL amyloidosis remains incurable, and all patients inevitably relapse. Hence, novel treatment options are needed for patients with an inadequate response or relapsed/refractory disease. B-cell maturation antigen (BCMA) is a tumour necrosis factor (TNF receptor superfamily receptor overexpressed on plasma cells in multiple myeloma (MM) and AL amyloidosis. Recently, several novel anti-BCMA immunotherapies have been approved for the treatment of relapsed/refractory MM, including antibody-drug conjugate belantamab mafodotin, bispecific antibodies teclistamab and elranatamab and chimeric antigen receptor T-cell therapies idecabtagene vicleucel and ciltacabtagene autoleucel. Despite lower expression than in MM, BCMA is also a promising target in AL amyloidosis. This review aims to provide up-to-date information on the efficacy and toxicity of anti-BCMA therapy in AL amyloidosis.

Safety and efficacy of B cell maturation antigen-directed CAR T-cell therapy in patients with relapsed/refractory multiple myeloma and concurrent light chain amyloidosis

Clinical trials evaluating chimeric antigen receptor (CAR) T-cell therapy in relapsed/refractory multiple myeloma (RRMM) have typically excluded patients with AL amyloidosis. As a result, there are limited data on the safety and efficacy of CAR T-cell therapy in this patient population. We retrospectively reviewed eight consecutive patients with RRMM and AL amyloidosis who were treated with standard of care CAR T-cell therapy. Cytokine release syndrome was seen in 75% of patients (grade ≥3: 0%) and immune effector cell-associated neurotoxicity syndrome (grade 1) in only one patient. Low-grade cytopenias were common (any grade/grade ≥3: neutropenia 62.5%/37.5%, anemia 37.5%/0%, thrombocytopenia 25%/0%). CAR T-cell therapy led to rapid and deep responses with a median time to best response of 43 days and a hematologic very good partial response or better rate of 62.5%. Overall, we found that commercial CAR T-cell therapy was feasible, and effective in patients with RRMM and concurrent AL amyloidosis.

Belantamab Mafodotin in Relapsed/Refractory AL Amyloidosis: Real-World Multi-Center Experience and Review of the Literature

INTRODUCTION

Treatment for relapsed/refractory AL amyloidosis (AL) is an unmet need. The safety and efficacy of belantamab mafodotin (BLM) in multiple myeloma are known, whereas in AL data are limited.

METHODS

We report a multi-center cohort of AL patients receiving BLM, and review all previous data on BLM therapy in AL.

RESULTS

Twelve patients with a median of 3 (range 2-9) prior lines of therapy were included. The overall hematological response rate (ORR) was 75% (9/12), including 5 complete responses. Six of the 10 evaluable patients had organ responses. The median event-free survivals/overall survivals were 22.3 and 28.8 months, respectively. Grade 3 toxicities were mostly infections and keratopathy, occurring in 7/12 (58%). Hematological toxicities were rare. No grade 4/5 toxicities occurred. The review of the previous series reveals BLM provides an ORR of 60-83% with similar rates of corneal toxicity.

CONCLUSION

BLM, being an off-the-shelf therapy, with acceptable toxicity even in frail patients, may be a valuable option in AL, with a high ORR, and a signal for durable responses and high-quality organ responses.

Options for Rescue Treatment of Patients with AL Amyloidosis Exposed to Upfront Daratumumab

PURPOSE OF REVIEW

This review aims to assess the therapeutic strategies available for relapsed/refractory patients with immunoglobulin light chain (AL) amyloidosis who received upfront daratumumab-based regimens.

RECENT FINDINGS

The treatment landscape of AL amyloidosis has changed radically thanks to the introduction in the upfront setting of daratumumab in combination with bortezomib, cyclophosphamide and dexamethasone (DaraCyBorD) which improved patients' outcomes increasing the rate of hematologic and organ responses. However, many patients eventually relapse or are refractory to daratumumab and the best salvage therapy is not well defined yet. In this contest, we reviewed the available therapeutic options after daratumumab failure, and we look towards the current advances in Bcl-2 inhibitors, novel immunotherapeutic agents as chimeric antigen receptor (CAR-T) therapy and bispecific antibodies (bsAbs). Relapsed/refractory AL amyloidosis represent an unmet clinical need and novel targeted drugs require urgent prospective assessment.

Current progress in CAR-based therapy for kidney disease

Despite significant breakthroughs in the understanding of immunological and pathophysiological features for immune-mediated kidney diseases, a proportion of patients exhibit poor responses to current therapies or have been categorized as refractory renal disease. Engineered T cells have emerged as a focal point of interest as a potential treatment strategy for kidney diseases. By genetically modifying T cells and arming them with chimeric antigen receptors (CARs), effectively targeting autoreactive immune cells, such as B cells or antibody-secreting plasma cells, has become feasible. The emergence of CAR T-cell therapy has shown promising potential in directing effector and regulatory T cells (Tregs) to the site of autoimmunity, paving the way for effective migration, proliferation, and execution of suppressive functions. Genetically modified T-cells equipped with artificial receptors have become a novel approach for alleviating autoimmune manifestations and reducing autoinflammatory events in the context of kidney diseases. Here, we review the latest developments in basic, translational, and clinical studies of CAR-based therapies for immune-mediated kidney diseases, highlighting their potential as promising avenues for therapeutic intervention.

Consensus guidelines and recommendations for the management and response assessment of chimeric antigen receptor T-cell therapy in clinical practice for relapsed and refractory multiple myeloma: a report from the International Myeloma Working Group Immunotherapy Committee

Chimeric antigen receptor (CAR) T-cell therapy has shown promise in patients with late-line refractory multiple myeloma, with response rates ranging from 73 to 98%. To date, three products have been approved: Idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel), which are approved by the US Food and Drug Administration, the European Medicines Agency, Health Canada (ide-cel only), and Brazil ANVISA (cilta-cel only); and equecabtagene autoleucel (eque-cel), which was approved by the Chinese National Medical Products Administration. CAR T-cell therapy is different from previous anti-myeloma therapeutics with unique toxic effects that require distinct mitigation strategies. Thus, a panel of experts from the International Myeloma Working Group was assembled to provide guidance for clinical use of CAR T-cell therapy in myeloma. This consensus opinion is from experts in the field of haematopoietic cell transplantation, cell therapy, and multiple myeloma therapeutics.

Multiple myeloma with secondary amyloidosis: Dysphagia as the first symptom: A case report

RATIONALE

Multiple myeloma (MM) with secondary amyloidosis (AL) is a rare clonal plasma cell proliferation disease, which causes dysfunction of multiple organs and tissues. We report a case of dysphagia as the first symptom in a patient with MM and secondary AL.

PATIENT CONCERNS

The patient was a 73-year-old female, was admitted to our hospital, because of progressive dysphagia for 4 months and limb weakness for 1 month.

DIAGNOSES

The bone marrow smear and pathology diagnosis revealed the presence of MM, while the biceps myopathy diagnosis indicated AL.

INTERVENTIONS

The VCD regimen consisted of bortezomib at a dosage of 1.9 mg on days 1, 8, 15, and 22, cyclophosphamide 0.4 g on days 1, 8, and 15, and dexamethasone at a dosage of 40 mg on days 1, 8, 15, and 22. The patient simultaneously received comprehensive treatment including anti-infective therapy, enhanced cardiac function, and nutritional support.

OUTCOMES

The M protein in the blood and urine protein were negative, indicating a reduction in bone marrow plasma cells to 2%. Flow cytometric analysis revealed a minimal percentage 0.04%. As a result, complete remission was achieved.

LESSONS

The clinical manifestations of MM exhibit a wide range, with the symptoms of secondary injury causing significant disturbing, while the atypical symptoms of extramedullary manifestations pose challenges in diagnosing the disease.

Immune Therapies in AL Amyloidosis-A Glimpse to the Future

Light-chain (AL) amyloidosis is a rare plasma cell disorder characterized by the deposition of misfolded immunoglobulin light chains in target organs, leading to multi-organ dysfunction. Treatment approaches have historically mirrored but lagged behind those of multiple myeloma (MM). Recent advancements in MM immunotherapy are gradually being evaluated and adopted in AL amyloidosis. This review explores the current state of immunotherapeutic strategies in AL amyloidosis, including monoclonal antibodies, antibody-drug conjugates, bispecific antibodies, and chimeric antigen receptor T-cell therapy. We discuss the unique challenges and prospects of these therapies in AL amyloidosis, including the exposure of frail AL amyloidosis patients to immune-mediated toxicities such as cytokine release syndrome (CRS) and immune effector-cell-associated neurotoxicity syndrome (ICANS), as well as their efficacy in promoting rapid and deep hematologic responses. Furthermore, we highlight the need for international initiatives and compassionate programs to provide access to these promising therapies and address critical unmet needs in AL amyloidosis management. Finally, we discuss future directions, including optimizing treatment sequencing and mitigating toxicities, to improve outcomes for AL amyloidosis patients.

[Organizational and budgetary impacts of the implementation of CAR-T cell therapies in a French academic hospital]

Belonging to the family of advanced therapy medicinal products, CAR-T cells have changed the management of hematological malignancies. These treatments are known to involve many actors in a complex process. The quotation of hospital stays associated with this therapeutic strategy is also unusual since there is currently no specific quotation. From November 2021 to May 2022, a study was conducted at the Nancy University Hospital to evaluate the organizational impact of CAR-T cell therapy on hospital actors and the budgetary impact of stays in care centers. Through this study, we have shown significant and variable organizational impacts: from 3.12% of an additional full-time equivalent for an administrative manager to 41.5% for a clinical research associate. These times, when compared to the hourly rates of the actors, generated high costs: 6582.81 € per patient, i.e. 15.60% of the total cost of hospitalization. Taking into account the current refund of hospital stays and the costs calculated above, the balance of an average hospital stay is a deficit of 674.10 € [±10,224.79] with a median of 1334.97 €. This study highlighted the workload generated by the management of these new therapies, as well as the fragile balance of financing hospital stays. To date, it seems necessary and even essential to adapt the quotations of the acts dedicated to CAR-T cells activity and to provide adequate funding through an adapted pricing system.

Anti-B Cell Maturation Antigen Chimeric Antigen Receptor T Cell Therapy for the Treatment of AL Amyloidosis and Concurrent Relapsed/Refractory Multiple Myeloma: Preliminary Efficacy and Safety

While immunotherapies, such as CAR T therapy and bi-specific antibodies, have revolutionized the treatment of multiple myeloma (MM), patients with AL amyloidosis have been excluded from trials with these agents due to concerns of underlying autonomic, cardiac, and renal dysfunction, leading to potentially fatal toxicities from these therapies. In this communication, we described the outcomes of two patients with AL amyloidosis and concurrent MM with underlying cardiac and/or renal dysfunction who underwent anti-BCMA CAR T cell therapy with ide-cel or cilta-cel, received cytokine release syndrome prophylaxis, and tolerated therapy well with manageable toxicities and achieved a MRD-negative state. We described the preliminary efficacy and safety of CAR T in patients with AL amyloidosis and highlighted the importance of patient selection and medical optimization of cardiac and renal function prior to CAR T.

First third-generation CAR T cell application targeting CD19 for the treatment of systemic IgM AL amyloidosis with underlying marginal zone lymphoma

Light chain amyloidosis (AL) is a rare disease caused by the generalized deposition of misfolded free light chains. Patients with immunoglobulin M gammopathy (IgM) and indolent B-cell lymphoma such as marginal zone lymphoma (MZL) may in some instances develop AL amyloidosis. So far, CAR T cells for AL amyloidosis have only been reported utilizing the B cell maturation antigen as target, while CD19 has so far not been used in AL amyloidosis.We report the case of a 71-year-old male, diagnosed with systemic AL kappa amyloidosis and MZL, receiving third-generation CAR T cell therapy targeting CD19. Prior treatment included bendamustine/rituximab and cyclophosphamide/ dexamethasone with subsequent autologous stem cell transplantation. CAR T application was well tolerated despite heart and kidney amyloid manifestations, and only early low-grade procedure-specific toxicities were observed. A continuous decrease in IgM, kappa light chains and kappa-to-lambda light chain difference was observed in the patient from day + 30 on, resulting in a deep hematological response six months after treatment.In summary, we present a novel case of CAR T cell treatment with third generation CD19 directed infusion for AL amyloidosis with an underlying secretory active B cell lymphoma, showing that this is an effective treatment modality and can be applied to patients with subsequent AL amyloidosis.

Advancements and future trends of immunotherapy in light-chain amyloidosis

Light-chain (AL) amyloidosis is a type of plasma cell neoplasm with abnormal monoclonal immunoglobulin light-chain production and their subsequent deposition in tissues causing end-organ damage. In addition to existing treatments including autologous stem cell transplantation, there is a need for other approaches for eradicating abnormal plasma cells and amyloid tissue deposits. Treatment strategies of AL amyloidosis are mostly based on medications that are effective in multiple myeloma due to similar cell of origin. Daratumumab along with proteasome inhibitors and corticosteroids has become standard of care for AL amyloidosis. Another appealing approach is disassembling amyloid deposits with hope to potentially reverse the damage done by the disease. This was met with promising results for CAEL-101 and birtamimab. Although still in early stages, novel treatment options in pipeline, including antibody-drug conjugates, bispecific T-cell engagers, and chimeric antigen receptor T cell therapy may diversify the treatment armamentarium of AL amyloidosis in the future.

Diagnostic and Treatment Strategies for AL Amyloidosis in an Era of Therapeutic Innovation

Despite significant progress and improving outcomes in the management of plasma cell disorders, AL amyloidosis remains diagnostically and therapeutically challenging for clinicians across practice settings. There is, however, a reason for optimism with the advent of new combination therapy approaches and novel targets offering the promise of improvement in end organ function, survival, and quality of life. This review offers a clinically applicable overview of an approach to diagnosis, risk stratification, and clinical management of AL amyloidosis in an era of rapid therapeutic innovation.

The exploration of B cell maturation antigen expression in plasma cell dyscrasias beyond multiple myeloma

BACKGROUND

B cell maturation antigen (BCMA) targeted immunotherapies have demonstrated remarkable clinical efficacy in multiple myeloma (MM). Here, we evaluated the BCMA expression in MM and other plasma cell dyscrasias (PCDs), hoping to provide a potential treatment strategy for the relapsed/refractory PCDs besides MM.

METHODS

From January 2018 to August 2021, 377 patients with PCDs were enrolled in this study, including 334 MM, 21 systemic light chain amyloidosis (AL), 5 POEMS syndrome, 14 monoclonal gammopathy of undetermined significance (MGUS), and three monoclonal gammopathy of renal significance (MGRS). The membrane-bound BCMA expression measured by multiparameter flow cytometry was defined by BCMA positivity rate and the mean fluorescence intensity (MFI).

RESULTS

The patients with MM had a median BCMA positive rate of 88.55% (range, 0.2% - 99.9%) and median BCMA MFI of 1281 (range, 109 - 48586). While the median BCMA positive rate in other PCDs was 55.8% (6.2% -98.9%), and the median BCMA MFI was 553 (182- 5930). BCMA expression level was negatively associated with hemoglobin concentration in multivariate analysis in terms of BCMA positive rate and MFI.

CONCLUSIONS

In conclusion, BCMA has the potential to be a therapeutic target for other PCDs besides MM.

Diagnosis and Treatment of AL Amyloidosis

Systemic light chain (AL) amyloidosis is caused by an usually small B cell clone that produces a toxic light chain forming amyloid deposits in tissue. The heart and kidney are the major organs affected, but all others, with the exception of the CNS, can be involved. The disease is rapidly progressive, and it is still diagnosed late. Screening programs in patients followed by hematologists for plasma cell dyscrasias should be considered. The diagnosis requires demonstration in a tissue biopsy of amyloid deposits formed by immunoglobulin light chains. The workup of patients with AL amyloidosis requires adequate technology and expertise, and patients should be referred to specialized centers whenever possible. Stagings are based on cardiac and renal biomarkers and guides the choice of treatment. The combination of daratumumab, cyclophosphamide, bortezomib and dexamethasone (dara-CyBorD) is the current standard of care. Autologous stem cell transplant is performed in eligible patients, especially those who do not attain a satisfactory response to dara-CyBorD. Passive immunotherapy targeting the amyloid deposits combined with chemo-/immune-therapy targeting the amyloid clone is currently being tested in controlled clinical trials. Response to therapy is assessed based on validated criteria. Profound hematologic response is the early goal of treatment and should be accompanied over time by deepening organ response. Many relapsed/refractory patients are also treated with daratumumab combination, but novel regimens will be needed to rescue daratumumab-exposed subjects. Immunomodulatory drugs are the current cornerstone of rescue therapy, while immunotherapy targeting B-cell maturation antigen and inhibitors of Bcl-2 are promising alternatives.

Bad players in AL amyloidosis in the current era of treatment

INTRODUCTION

Systemic AL amyloidosis (ALA) is a clonal plasma cell (PC) disease characterized by deposition of amyloid fibrils in different organs and tissues. Traditionally, the prognosis of ALA is poor and is primarily defined by cardiac involvement. The modern prognostic models are based on cardiac markers and free light chain difference (dFLC). Cardiac biomarkers have low specificity and are dependent on renal function, volume status, and cardiac diseases other than ALA. New therapies significantly improved the prognosis of the disease. The advancements in technologies - cardiac echocardiography (ECHO) and cardiac MRI (CMR), as well as new biological markers, relying on cardiac injury, inflammation, endothelial damage, and clonal and non-clonal PC markers are promising.

AREAS COVERED

An update on the prognostic significance of cardiac ALA, number of involved organs, response to treatment, including minimal residual disease (MRD), ECHO, MRI, and new biological markers will be discussed. The literature search was done in PubMed and Google Scholar, and the most recent and relevant data are included.

EXPERT OPINION

Prospective multicenter trials, evaluating multiple clinical and laboratory parameters, should be done to improve the risk assessment models in ALA in the modern era of therapy.

Feasibility of a Novel Academic BCMA-CART (HBI0101) for the Treatment of Relapsed and Refractory AL Amyloidosis

PURPOSE

AL amyloidosis (AL) treatments are generally based on those employed for multiple myeloma. Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T (CART)-cell therapy, already approved for multiple myeloma, might be too toxic for patients with AL.

EXPERIMENTAL DESIGN

Here we describe the ex vivo applicability of a novel in-house, academic anti-BCMA CAR construct on AL primary cells, as well as the safety and efficacy in 4 patients with relapsed/refractory (RR) primary AL, treated in a phase I clinical trial (NCT04720313).

RESULTS

Three had MAYO stage IIIa cardiac involvement at enrollment. The treatment proved relatively safe, with a short and manageable grade 3 cytokine release syndrome evident in 2 patients and no neurotoxicity in any. Cardiac decompensations, observed in 2 patients, were also short and manageable. The overall hematologic response and complete response rates were observed in all patients with an organ response evident in all four. Within a median follow-up period of 5.2 (2.5-9.5) months, all 4 patients maintained their responses.

CONCLUSIONS

BCMA-CART cells provide a first proof-of-concept that this therapy is safe enough and highly efficacious for the treatment of patients with advanced, RR AL.

T cells isolated from G-CSF-treated multiple myeloma patients are suitable for the generation of BCMA-directed CAR-T cells

Autologous cell immunotherapy using B cell maturation antigen (BCMA)-targeted chimeric antigen receptor (CAR)-T cells is an effective novel treatment for multiple myeloma (MM). This therapy has only been used for relapsed and refractory patients, at which stage the endogenous T cells used to produce the CAR-T cells are affected by the immunosuppressive nature of advanced MM and/or side effects of previous therapies. An alternative pool of "fitter" T cells is found in leukocytoapheresis products that are routinely collected to obtain hematopoietic progenitor cells for autologous stem cell transplantation (ASCT) early in the treatment of MM. However, to mobilize the progenitor cells, patients are dosed with granulocyte colony-stimulating factor (G-CSF), which is reported to adversely affect T cell proliferation, function, and differentiation. Here, we aimed to first establish whether G-CSF treatment negatively influences T cell phenotype and to ascertain whether previous exposure of T cells to G-CSF is deleterious for anti-BCMA CAR-T cells. We observed that G-CSF had a minimal impact on T cell phenotype when added in vitro or administered to patients. Moreover, we found that CAR-T cell fitness and anti-tumor activity were unaffected when generated from G-CSF-exposed T cells. Overall, we showed that ASCT apheresis products are a suitable source of T cells for anti-BCMA CAR-T cell manufacture.

Patient selection for CAR T or BiTE therapy in multiple myeloma: Which treatment for each patient?

Multiple myeloma (MM) is a plasma cell malignancy that affects an increasing number of patients worldwide. Despite all the efforts to understand its pathogenesis and develop new treatment modalities, MM remains an incurable disease. Novel immunotherapies, such as CAR T cell therapy (CAR) and bispecific T cell engagers (BiTE), are intensively targeting different surface antigens, such as BMCA, SLAMF7 (CS1), GPRC5D, FCRH5 or CD38. However, stem cell transplantation is still indispensable in transplant-eligible patients. Studies suggest that the early use of immunotherapy may improve outcomes significantly. In this review, we summarize the currently available clinical literature on CAR and BiTE in MM. Furthermore, we will compare these two T cell-based immunotherapies and discuss potential therapeutic approaches to promote development of new clinical trials, using T cell-based immunotherapies, even as bridging therapies to a transplant.

Post-mortem neuropathologic examination of a 6-case series of CAR T-cell treated patients

Introduction: Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapy for the treatment of refractory hematopoietic malignancies. Adverse events are common, and neurotoxicity is one of the most important. However, the physiopathology is unknown and neuropathologic information is scarce. Materials and methods: Post-mortem examination of 6 brains from patients that underwent CAR T-cell therapy from 2017 to 2022. In all cases, polymerase chain reaction (PCR) in paraffin blocks for the detection of CAR T cells was performed. Results: Two patients died of hematologic progression, while the others died of cytokine release syndrome, lung infection, encephalomyelitis, and acute liver failure. Two out of 6 presented neurological symptoms, one with extracranial malignancy progression and the other with encephalomyelitis. The neuropathology of the latter showed severe perivascular and interstitial lymphocytic infiltration, predominantly CD8+, together with a diffuse interstitial histiocytic infiltration, affecting mainly the spinal cord, midbrain, and hippocampus, and a diffuse gliosis of basal ganglia, hippocampus, and brainstem. Microbiological studies were negative for neurotropic viruses, and PCR failed to detect CAR T -cells. Another case without detectable neurological signs showed cortical and subcortical gliosis due to acute hypoxic-ischemic damage. The remaining 4 cases only showed a mild patchy gliosis and microglial activation, and CAR T cells were detected by PCR only in one of them. Conclusions: In this series of patients that died after CAR T-cell therapy, we predominantly found non-specific or minimal neuropathological changes. CAR T-cell related toxicity may not be the only cause of neurological symptoms, and the autopsy could detect additional pathological findings.