Prevalence and variation of CHIP in patients with aggressive lymphomas undergoing CD19-directed CAR-T-cell treatment

Myeloid neoplasms after CD19-directed CAR T cells therapy in long-term B-cell lymphoma responders, a rising risk over time?

Therapy-related myeloid neoplasms (t-MN), including myelodysplastic neoplasms (t-MDS) and acute myeloid leukemia (t-AML), have emerged as significant late complications after CAR T cell therapy. We retrospectively analyzed 539 patients with B cell lymphoma treated with CD19 directed CAR T cell therapy across four French centers. Cumulative incidences of t-MN was estimated with relapse or death treated as competing risk. Univariate and propensity score matching (PSM) analyses were conducted to assess risk factors with age and the number of prior treatments as covariates. After a median follow-up of 25 months, the cumulative incidence of t-MN was 4.5% at 2 years. T-MN occurred predominantly as t-MDS (62%) and t-AML (38%) with high cytogenetic risk. Median overall survival after t-MN diagnosis was 4.5 months. In univariate analysis, older age (p < 0.01), higher MCV (p < 0.01), and higher ICANS grade (p = 0.04) were associated with increased risk of t-MN. After PSM, MCV and ICANS grade remained significant risk factors. CAR T cell products with CD28 co-stimulatory domains trended towards higher t-MN risk (p = 0.09). NGS analysis showed that 85.7% of t-MN had pre-existing mutations, most commonly TP53. This study highlights t-MN as a severe late complication of CAR T cell therapy. MCV and ICANS grade were identified as key risk factors.

T cell malignancies after CAR T cell therapy in the DESCAR-T registry

The risk of T cell malignancies after chimeric antigen receptor (CAR) T cell therapy is a concern, although the true incidence remains unclear. Here we analyzed the DESCAR-T registry database, encompassing all pediatric and adult patients with hematologic malignancies who received CAR T cell therapy in France since 1 July 2018. Of the 3,066 patients included (2,536 B cell lymphoma, 162 B cell acute lymphoblastic leukemia (ALL) and 368 multiple myeloma), 1,680 (54.8%) received axicabtagene ciloleucel, 205 (6.7%) brexucabtagene autoleucel, 44 (1.4%) lisocabtagene maraleucel and 769 (25.1%) tisagenlecleucel. All multiple myeloma patients received idecabtagene vicleucel, with none receiving ciltacabtagene autoleucel. After a median follow-up of 12.7 months for B cell lymphoma, 17.7 months for B cell ALL and 6.3 months for multiple myeloma, only one (0.03%) patient developed a T cell malignancy after CAR T infusion. Specifically, the patient was diagnosed with a primary cutaneous CD30+ T cell lymphoproliferative disorder (anaplastic lymphoma kinase-negative) 3 years after receiving tisagenlecleucel therapy for diffuse large B cell lymphoma. This was associated with the integration of a CAR clone into the tumor suppressor gene PLAAT4 (phospholipase A and acyltransferase 4). Thus, the development of this secondary T cell malignancy might be linked to the use of CAR T cell therapy. In conclusion, our findings indicate a very low risk of T cell malignancy after CAR T cell therapy.

Clonal hematopoiesis of indeterminate potential: the root cause of, and fertile ground for, hematological malignancies

Clonal hematopoiesis (CH) of indeterminate potential (CHIP), characterized by propagation of blood cell clones carrying somatic mutations in specific driver genes, is increasingly recognized as a critical factor in the development of hematological malignancies. This phenomenon, which often emerges with age, underscores the complex interplay between genetic predisposition and environmental influences in cancer initiation and progression. Recent years have witnessed significant advances in our understanding of the link between CHIP and hematological diseases. In this review, we provide a comprehensive overview of the features of CHIP and explore its role in promoting tumorigenesis and influencing treatment outcomes for blood cancers. Finally, we summarize current available tools for risk stratification and discuss management strategies for patients with CHIP.

Clonal hematopoiesis of indeterminate potential (CHIP): A potential contributor to lymphoma

Clonal hematopoiesis (CH) typically refers to the clonal expansion of hematopoietic stem cells (HSCs) due to genetic mutations, serving as the pathogenic basis for various diseases. Clonal hematopoiesis of indeterminate potential (CHIP) is a subtype of CH, emerging as a significant risk factor for myeloid malignancies and cardiovascular diseases, which has attracted increasing attention. However, recent research has unveiled previously overlooked links between CHIP and lymphoma. This paper reviews the relationship between CHIP and lymphoma, focusing on the role and mechanism of TET2 and DNMT3A-mediated CHIP in lymphoma from the perspective of laboratory research and clinical observation. Additionally, we explore the therapeutic implications of targeting CHIP genes and inflammatory pathways in lymphoma. Our findings underscore the multifaceted influence of CHIP on lymphoma development and provide a promising avenue for therapeutic interventions in CHIP mediated lymphoma.

Impact of immunological aging on T cell-mediated therapies in older adults with multiple myeloma and lymphoma

The treatment landscape for lymphoma and multiple myeloma, which disproportionally affect older adults, has been transformed by the advent of T cell-mediated immunotherapies, including immune checkpoint inhibition, T cell-engaging bispecific antibodies, and chimeric antigen receptor (CAR) T cell therapy, during the last decade. These treatment modalities re-enable the patient's own immune system to combat malignant cells and offer the potential for sustained remissions and cure for various diseases.Age profoundly affects the physiological function of the immune system. The process of biological aging is largely driven by inflammatory signaling, which is reciprocally fueled by aging-related alterations of physiology and metabolism. In the T cell compartment, aging contributes to T cell senescence and exhaustion, increased abundance of terminally differentiated cells, a corresponding attrition in naïve T cell numbers, and a decrease in the breadth of the receptor repertoire. Furthermore, inflammatory signaling drives aging-related pathologies and contributes to frailty in older individuals. Thus, there is growing evidence of biological aging modulating the efficacy and toxicity of T cell-mediated immunotherapies.Here, we review the available evidence from biological and clinical studies focusing on the relationship between T cell-mediated treatment of hematologic malignancies and age. We discuss biological features potentially impacting clinical outcomes in various scenarios, and potential strategies to improve the safety and efficacy of immune checkpoint inhibitors, T cell-engaging bispecific antibodies, and CAR-T cell therapy in older patients.

New insights into CAR T-cell hematological toxicities: manifestations, mechanisms, and effective management strategies

Chimeric antigen receptor (CAR) T-cell therapy represents a highly efficacious treatment modality demonstrated to enhance outcomes in patients afflicted with malignancies, particularly those enduring relapsed or refractory hematological malignancies. However, the escalating adoption of CAR T-cell therapy has unveiled several life-threatening toxicities, notably cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), infections, and hematological toxicities (HTs), thereby hindering the broad implementation of CAR T-cell therapy. HTs encompass a spectrum of adverse effects, including cytopenias, hemophagocytic lymphohistiocytosis (HLH), coagulopathies, and B-cell aplasia. While our comprehension of the underlying mechanisms governing CRS and ICANS is advancing, the intricate pathophysiology of HTs remains inadequately elucidated. Such knowledge gaps may precipitate suboptimal therapeutic decisions, potentially culminating in substantial medical resource depletion and detriment to patients' quality of life. In this comprehensive review, based on recent updated findings, we delineate various mechanisms contributing to HTs subsequent to CAR T-cell therapy, explicate manifestations of HTs, and proffer strategic interventions to mitigate this relevant clinical challenge.

The Current Landscape of Secondary Malignancies after CAR T-Cell Therapies: How Could Malignancies Be Prevented?

Chimeric antigen receptor (CAR) T-cell therapies have revolutionised the field of haematological malignancies by achieving impressive remission rates in patients with highly refractory haematological malignancies, improving overall survival. To date, six commercial anti-CD19 and anti-BCMA CAR T-cell products have been approved by the Food and Drug Administration (FDA) for the treatment of relapsed/refractory B-cell haematological malignancies and multiple myeloma. The indications for CAR T-cell therapies are gradually expanding, with these therapies being investigated in a variety of diseases, including non-malignant ones. Despite the great success, there are several challenges surrounding CAR T-cell therapies, such as non-durable responses and high-grade toxicities. In addition, a new safety concern was added by the FDA on 28 November 2023 following reports of T-cell malignancies in patients previously treated with either anti-CD19 or anti-BCMA autologous CAR T-cell therapies both in clinical trials and in the real-world setting. Since then, several reports have been published presenting the incidence and analysing the risks of other secondary malignancies after CAR T-cell therapies. In this opinion article, the current landscape of secondary malignancies after CAR T-cell therapies is presented, along with a proposed strategy for future research aiming at potentially diminishing or abrogating the risk of developing secondary malignancies after CAR T-cell therapies.

Clinical and Therapeutic Implications of Clonal Hematopoiesis

Clonal hematopoiesis (CH) is an age-related process whereby hematopoietic stem and progenitor cells (HSPCs) acquire mutations that lead to a proliferative advantage and clonal expansion. The most commonly mutated genes are epigenetic regulators, DNA damage response genes, and splicing factors, which are essential to maintain functional HSPCs and are frequently involved in the development of hematologic malignancies. Established risk factors for CH, including age, prior cytotoxic therapy, and smoking, increase the risk of acquiring CH and/or may increase CH fitness. CH has emerged as a novel risk factor in many age-related diseases, such as hematologic malignancies, cardiovascular disease, diabetes, and autoimmune disorders, among others. Future characterization of the mechanisms driving CH evolution will be critical to develop preventative and therapeutic approaches.

CAR T-cell Resistance to Oncogenic Transformation

In this commentary, we discuss the investigation into reports of T-cell malignancies following chimeric antigen receptor T-cell therapy. We argue that although these cases should be thoroughly examined, current data suggest that such risks with autologous chimeric antigen receptor T cells are remarkably low compared with other cancer treatments. We also emphasize the importance of continued research, transparent reporting, and participation in postauthorization safety studies.

Immune effector cell-associated haematotoxicity after CAR T-cell therapy: from mechanism to management

Genetically engineered chimeric antigen receptor (CAR) T cells have become an effective treatment option for several advanced B-cell malignancies. Haematological side-effects, classified in 2023 as immune effector cell-associated haematotoxicity (ICAHT), are very common and can predispose for clinically relevant infections. As haematopoietic reconstitution after CAR T-cell therapy differs from chemotherapy-associated myelosuppression, a novel classification system for early and late ICAHT has been introduced. Furthermore, a risk stratification score named CAR-HEMATOTOX has been developed to identify candidates at high risk of ICAHT, thereby enabling risk-based interventional strategies. Therapeutically, growth factor support with granulocyte colony-stimulating factor (G-CSF) is the mainstay of treatment, with haematopoietic stem cell (HSC) boosts available for patients who are refractory to G-CSF (if available). Although the underlying pathophysiology remains poorly understood, translational studies from the past 3 years suggest that CAR T-cell-induced inflammation and baseline haematopoietic function are key contributors to prolonged cytopenia. In this Review, we provide an overview of the spectrum of haematological toxicities after CAR T-cell therapy and offer perspectives on future translational and clinical developments.

Senotherapy, cancer, and aging

INTRODUCTION

We aimed to highlight the effects of senotherapy on the prevention and treatment of cancer in older individuals. The aim of senotherapy is to eliminate senescent cells. These cells express the senescence-associated secretory phenotype (SASP). With production of inflammatory cytokines, growth factors, and different type of proteases, the SASP is responsible for aging-associated disability and diseases. All mammalian cells experience senescence. The main agents of aging include fibroblasts and adipose cells. Senescent tumor cells may undergo genomic reprogramming and re-enter cell cycle with a stem cell phenotype.

MATERIALS AND METHODS

We conducted a Medline search for the following key words: senotherapy, senolysis, senomorphic agents. We provide a narrative review of the finding.

RESULTS

Different agents may eliminate senescent cells from cell cultures and murine models. These include metformin, rapamycin, desatinib, quercitin, fisetin, ruloxitinib, and BCL2 inhibitors. A randomized controlled study of metformin in 3,000 patients aged 65-79 without glucose intolerance aiming to establish whether senotherapy may prevent or reverse disability and aging associated diseases, including cancer, is ongoing. Senotherapy prolongs the life span and decreases the incidence of cancer in experimental animal models, as well as delays and reverses disability. Senescent tumor cells are found prior to treatment and after chemotherapy and radiation. These elements may be responsible for tumor recurrence and treatment refractoriness.

DISCUSSION

Senotherapy may have substantial effects on cancer management including decreased incidence and aggressiveness of cancer, improved tolerance of antineoplastic treatment, and prevention of relapse after primary treatment. Senotherapy may ameliorate several complications of cancer chemotherapy.

T cell lymphoma and secondary primary malignancy risk after commercial CAR T cell therapy

We report a T cell lymphoma (TCL) occurring 3 months after anti-CD19 chimeric antigen receptor (CAR) T cell immunotherapy for non-Hodgkin B cell lymphoma. The TCL was diagnosed from a thoracic lymph node upon surgery for lung cancer. The TCL exhibited CD8+ cytotoxic phenotype and a JAK3 variant, while the CAR transgene was very low. The T cell clone was identified at low levels in the blood before CAR T infusion and in lung cancer. To assess the overall risk of secondary primary malignancy after commercial CAR T (CD19, BCMA), we analyzed 449 patients treated at the University of Pennsylvania. At a median follow-up of 10.3 months, 16 patients (3.6%) had a secondary primary malignancy. The median onset time was 26.4 and 9.7 months for solid and hematological malignancies, respectively. The projected 5-year cumulative incidence is 15.2% for solid and 2.3% for hematological malignancies. Overall, one case of TCL was observed, suggesting a low risk of TCL after CAR T.

Management of neurotoxicity syndrome complicated by autologous hematopoietic stem cell transplantation bridge to chimeric antigen receptor T-Cell therapy: A case report

Effectively addressing the challenges posed by relapsed and refractory diffuse large B-cell lymphoma, particularly when employing autologous hematopoietic stem cell transplantation and CAR-T therapy, requires a comprehensive approach to treatment and nursing. This case report emphasizes a nursing strategy focused on managing neurotoxicity post-CAR-T therapy. Nursing interventions include the identification of neurotoxicity symptoms, neuropsychiatric management, careful support during lumbar puncture and intrathecal administration, psychological assistance, and adaptive nutritional guidance. The diligent application of treatment and nursing care resulted in a remarkable recovery for the patient, as evidenced by the alleviation of central facial paralysis, improvement in swallowing function (from Grade 4 to Grade 2), and enhanced vocalization. Consistent and specialized nursing care is paramount for effectively managing complications, especially neurotoxicity, in patients undergoing CAR-T therapy. A thorough monitoring of symptoms and personalized care contribute to optimizing treatment outcomes and ensuring patient safety.

FLT3 Mutated Acute Myeloid Leukemia after CD19 CAR-t Cells

Chimeric Antigen Receptor T-cells have improved the life expectancy of severely pretreated patients with aggressive hematological cancers; for this reason, therapy-related myeloid leukemias are becoming of great concern in this field, despite their clonal phylogenesis and mutational landscape have not been fully explored yet. This case discusses a 33-year-old man with refractory large B-cell lymphoma, treated with Chimeric Antigen Receptor T-cell (CAR-T) therapy as the 7th line of treatment. Despite a persistent partial response, the patient developed therapy-related acute myeloid leukemia (t-AML) six months post-CAR-T, revealing pre-existing clonal hematopoiesis. The myeloid malignancy exhibited an unusual hypocellular/dysplastic pattern, progressing to an established blast phase with cytopenia. Treatment with demethylating agents and BCL2 inhibitors proved ineffective, leading to t-AML with hyperleukocytosis and FLT3-ITD gain, resulting in the patient's death. This case underscores the impact of severe pretreatment and bone marrow impairment in CAR-T-associated t-AML, emphasizing their role over insertional mutagenesis. Furthermore, it highlights the retention of classic therapy-related leukemia characteristics, including the potential for acquiring FLT3 mutations and displaying dysplastic morphology in these secondary leukemias.

Hematopoiesis and immune reconstitution after CD19 directed chimeric antigen receptor T-cells (CAR-T): A comprehensive review on incidence, risk factors and current management

Impaired function of hematopoiesis after treatment with chimeric antigen T-cells (CAR-T) is a frequent finding and can interest a wide range of patients, regardless of age and underlying disease. Trilinear cytopenias, as well as hypogammaglobulinemia, B-cell aplasia, and T-cell impairment, can severely affect the infectious risk of CAR-T recipients, as well as their quality of life. In this review, we provide an overview of defects in hematopoiesis after CAR-T, starting with a summary of different definitions and thresholds. We then move to summarize the main pathogenetic mechanisms of cytopenias, and we offer insight into cytomorphological aspects, the role of clonal hematopoiesis, and the risk of secondary myeloid malignancies. Subsequently, we expose the major findings and reports on T-cell and B-cell quantitative and functional impairment after CAR-T. Finally, we provide an overview of current recommendations and leading experiences regarding the management of cytopenias and defective B- and T-cell function.

Prognostic relevance of clonal hematopoiesis in myeloid neoplastic transformation in patients with follicular lymphoma treated with radioimmunotherapy

While novel radioisotope therapies continue to advance cancer care, reports of therapy-related myeloid neoplasms (t-MN) have generated concern. The prevalence and role of clonal hematopoiesis (CH) in this process remain to be defined. We hypothesized that: (i) CH is prevalent in relapsed follicular lymphoma and is associated with t-MN transformation, and (ii) radiation in the form of radioimmunotherapy (RIT) plays a role in clonal progression. In this retrospective cohort study, we evaluated the prevalence and prognostic impact of CH on clinical outcomes in 58 heavily pre-treated follicular lymphoma patients who received RIT. Patients had been given a median of four lines of therapy before RIT. The prevalence of CH prior to RIT was 46%, while it was 67% (P=0.15) during the course of RIT and subsequent therapies in the paired samples. Fourteen (24%) patients developed t-MN. Patients with t-MN had a higher variant allele fraction (38% vs. 15%; P=0.02) and clonal complexity (P=0.03) than those without. The spectrum of CH differed from that in age-related CH, with a high prevalence of DNA damage repair and response pathway mutations, absence of spliceosome mutations, and a paucity of signaling mutations. While there were no clear clinical associations between RIT and t-MN, or overall survival, patients with t-MN had a higher mutant clonal burden, along with extensive chromosomal abnormalities (median survival, afer t-MN diagnosis, 0.9 months). The baseline prevalence of CH was high, with an increase in prevalence on exposure to RIT and subsequent therapies. The high rates of t-MN with marked clonal complexities and extensive chromosomal damage underscore the importance of better identifying and studying genotoxic stressors accentuated by therapeutic modalities.

Molecular and clinical aspects relevant for counseling individuals with clonal hematopoiesis of indeterminate potential

Clonal hematopoiesis of indeterminate potential (CHIP) has fascinated the medical community for some time. Discovered about a decade ago, this phenomenon links age-related alterations in hematopoiesis not only to the later development of hematological malignancies but also to an increased risk of early-onset cardiovascular disease and some other disorders. CHIP is detected in the blood and is characterized by clonally expanded somatic mutations in cancer-associated genes, predisposing to the development of hematologic neoplasms such as MDS and AML. CHIP-associated mutations often involve DNA damage repair genes and are frequently observed following prior cytotoxic cancer therapy. Genetic predisposition seems to be a contributing factor. It came as a surprise that CHIP significantly elevates the risk of myocardial infarction and stroke, and also contributes to heart failure and pulmonary hypertension. Meanwhile, evidence of mutant clonal macrophages in vessel walls and organ parenchyma helps to explain the pathophysiology. Besides aging, there are some risk factors promoting the appearance of CHIP, such as smoking, chronic inflammation, chronic sleep deprivation, and high birth weight. This article describes fundamental aspects of CHIP and explains its association with hematologic malignancies, cardiovascular disorders, and other medical conditions, while also exploring potential progress in the clinical management of affected individuals. While it is important to diagnose conditions that can lead to adverse, but potentially preventable, effects, it is equally important not to stress patients by confronting them with disconcerting findings that cannot be remedied. Individuals with diagnosed or suspected CHIP should receive counseling in a specialized outpatient clinic, where professionals from relevant medical specialties may help them to avoid the development of CHIP-related health problems. Unfortunately, useful treatments and clinical guidelines for managing CHIP are still largely lacking. However, there are some promising approaches regarding the management of cardiovascular disease risk. In the future, strategies aimed at restoration of gene function or inhibition of inflammatory mediators may become an option.

Chimeric Antigen Receptor T-Cell Therapy in Aggressive B-Cell Lymphoma

Chimeric antigen receptor (CAR) T-cell therapy is a revolutionary therapy increasingly used in the treatment of non-Hodgkin B-cell lymphoma. This review focuses on the use of CAR T-cell therapy in aggressive B-cell lymphoma including clinical indications, known short- and long-term toxicity, mechanisms of CAR T-cell efficacy and tumor resistance, and future directions in the treatment of aggressive lymphoma with CAR T-cell therapy.

Clinical Implications and Dynamics of Clonal Hematopoiesis in Anti-CD19 CAR T-cell Treated Patients

Recent evidence revealed important interactions between clonal hematopoiesis (CH) and cellular therapies established for the treatment of hematologic malignancies. The impact of CH on safety, efficacy, and outcome of chimeric antigen receptor (CAR) T-cell therapy is currently under investigation. We analyzed 110 patients with relapsed/refractory B-cell non-Hodgkin lymphoma (n = 105) or acute lymphoblastic leukemia (ALL) (n = 5), treated with Axicabtagene-Ciloleucel (39%), Tisagenlecleucel (51%), or Brexucabtagene autoleucel (10%). Using error-corrected targeted sequencing, a high CH prevalence of 56.4% (variant allele frequency [VAF] ≥1%) at the time of CAR T-cell infusion was detected. The most frequently mutated gene was PPM1D followed by DNMT3A, TET2, ASXL1, and TP53. Variant allele frequencies were significantly lower in B and T cells compared with monocytes and granulocytes. CH did not increase the risk of CAR T-related toxicities. The incidences of cytokine release syndrome and immune effector-cell-associated neurotoxicity syndrome were similar between CHpos and CHneg patients, regardless of clone size, age, or CAR T product. Prolonged cytopenias were not associated with CH. Best overall response rates (ORRs) were numerically but not significantly higher in CHpos patients (ORR 76.7% versus 62.2%; P = 0.13). Furthermore, CH status did not predict progression-free survival or overall survival. Lastly, sequential analysis showed a modest VAF increase of 1.3% and acquisition of novel mutations within 100 days postinfusion. CH was frequent in large B-cell lymphoma/ALL patients receiving CAR T-cells but did not affect toxicity nor treatment response or outcome.

Immune effector cell-associated hematotoxicity: EHA/EBMT consensus grading and best practice recommendations

Hematological toxicity is the most common adverse event after chimeric antigen receptor (CAR) T-cell therapy. Cytopenias can be profound and long-lasting and can predispose for severe infectious complications. In a recent worldwide survey, we demonstrated that there remains considerable heterogeneity in regard to current practice patterns. Here, we sought to build consensus on the grading and management of immune effector cell-associated hematotoxicity (ICAHT) after CAR T-cell therapy. For this purpose, a joint effort between the European Society for Blood and Marrow Transplantation (EBMT) and the European Hematology Association (EHA) involved an international panel of 36 CAR T-cell experts who met in a series of virtual conferences, culminating in a 2-day meeting in Lille, France. On the basis of these deliberations, best practice recommendations were developed. For the grading of ICAHT, a classification system based on depth and duration of neutropenia was developed for early (day 0-30) and late (after day +30) cytopenia. Detailed recommendations on risk factors, available preinfusion scoring systems (eg, CAR-HEMATOTOX score), and diagnostic workup are provided. A further section focuses on identifying hemophagocytosis in the context of severe hematotoxicity. Finally, we review current evidence and provide consensus recommendations for the management of ICAHT, including growth factor support, anti-infectious prophylaxis, transfusions, autologous hematopoietic stem cell boost, and allogeneic hematopoietic cell transplantation. In conclusion, we propose ICAHT as a novel toxicity category after immune effector cell therapy, provide a framework for its grading, review literature on risk factors, and outline expert recommendations for the diagnostic workup and short- and long-term management.

Clonal Hematopoiesis: Updates and Implications at the Solid Tumor-Immune Interface

Recent larger-scale studies of patients with cancer and longitudinal population cohorts have revealed how age-related expansions of mutant hematopoietic cells (clonal hematopoiesis [CH]) have differential associations with incident and prevalent cancers and their outcomes. Increasing recognition and deeper understanding of genetic subtypes of CH are yielding insights into the tumor-immune interface that may help to explain the heterogeneous impact of CH on tumorigenesis and treatment. Herein, we update the expanding influence of CH in precision oncology and propose important research and clinical questions to address to effectively manage and harness CH in oncology patients.

Inflammatory abrasion of hematopoietic stem cells: a candidate clue for the post-CAR-T hematotoxicity?

Chimeric antigen receptor T-cell (CAR-T) therapy has shown remarkable effects in treating various hematological malignancies. However, hematotoxicity, specifically neutropenia, thrombocytopenia, and anemia, poses a serious threat to patient prognosis and remains a less focused adverse effect of CAR-T therapy. The mechanism underlying lasting or recurring late-phase hematotoxicity, long after the influence of lymphodepletion therapy and cytokine release syndrome (CRS), remains elusive. In this review, we summarize the current clinical studies on CAR-T late hematotoxicity to clarify its definition, incidence, characteristics, risk factors, and interventions. Owing to the effectiveness of transfusing hematopoietic stem cells (HSCs) in rescuing severe CAR-T late hematotoxicity and the unignorable role of inflammation in CAR-T therapy, this review also discusses possible mechanisms of the harmful influence of inflammation on HSCs, including inflammatory abrasion of the number and the function of HSCs. We also discuss chronic and acute inflammation. Cytokines, cellular immunity, and niche factors likely to be disturbed in CAR-T therapy are highlighted factors with possible contributions to post-CAR-T hematotoxicity.

CHIP Happens: Clonal Hematopoiesis of Indeterminate Potential and Its Relationship to Solid Tumors

Clonal hematopoiesis of indeterminate potential (CHIP) is characterized by the expansion of hematopoietic cells harboring leukemia-associated somatic mutations in otherwise healthy people and occurs in at least 10% of adults over 70. It is well established that people with CHIP have increased rates of hematologic malignancy, increased risk of cardiovascular disease, and worse all-cause mortality compared with those without CHIP. Despite recent advancements in understanding CHIP as it relates to these known outcomes, much remains to be learned about the development and role of CHIP in other disease states. Emerging research has identified high rates of CHIP in patients with solid tumors, driven in part by oncologic therapy, and revealed associations between CHIP and differential outcomes in both solid tumors and other diseases. Recent studies have demonstrated that CHIP can contribute to dysregulated inflammatory signaling in multiple contexts, underscoring the importance of interrogating how CHIP might alter tumor immunology. Here, we review the role of CHIP mutations in clonal expansion of hematopoietic cells, explore the relationship between CHIP and solid tumors, and discuss the potential roles of CHIP in inflammation and solid tumor biology.

CHIPing away the progression potential of CHIP: A new reality in the making

Over the past few years, we have gained a deeper understanding of clonal hematopoiesis of indeterminate potential (CHIP), especially with regard to the epidemiology, clinical sequelae, and mechanical aspects. However, interventional strategies to prevent or delay the potential negative consequences of CHIP remain underdeveloped. In this review, we highlight the latest updates on clonal hematopoiesis research, including molecular mechanisms and clinical implications, with a particular focus on the evolving strategies for the interventions that are being evaluated in ongoing observational and interventional trials. There remains an urgent need to formulate standardized and evidence-based recommendations and guidelines for evaluating and managing individuals with clonal hematopoiesis. In addition, patient-centric endpoints must be defined for clinical trials, which will enable us to continue the robust development of effective preventive strategies and improve clinical outcomes.

Fatal Progression of Mutated TP53-Associated Clonal Hematopoiesis following Anti-CD19 CAR-T Cell Therapy

We present the case of a 64-year-old man diagnosed with large B-cell lymphoma who relapsed twice after standard-of-care therapy. Due to persisting cytopenia, Next generation sequencing analysis was performed, revealing a small TP53-mutated clone. As a third-line therapy, the patient was treated with CAR-T cells, which resulted in complete remission. However, this treatment also led to the expansion of the TP53-mutated clone and therapy-related myelodysplasia with a complex aberrant karyotype. This case may serve as a paradigmatic example of clonal hematopoietic progression in a patient undergoing CAR-T cell therapy, especially in the context of a TP53-mutated clone.

[Relevance of clonal hematopoiesis for cellular therapies]

The detection of clonal hematopoiesis (CH) in patients with hematologic neoplasms who are undergoing a cellular therapy is common. The most frequently used cellular therapy procedures include autologous and allogeneic hematopoietic stem cell transplantation (HSCT) and, more recently, chimeric antigen receptor (CAR) T‑cell therapy. All three procedures differ fundamentally in terms of harvesting and manufacturing aspects as well as usage of the respective cell product. Therefore, the importance of CH in relation to the respective treatment method must be evaluated and assessed differently. In autologous HSCT, the extent of previous cytotoxic therapy significantly contributes to the high prevalence of CH. The clinically most important aspect is the development of secondary neoplasms from a pre-existing CH clone and the potential risk for enhanced cardiovascular side effects. In allogeneic HSCT, the donor selection with respect to the age largely determines the probability for the presence of CH. In this setting, the development of secondary malignancies only plays a minor role compared to the autologous HSCT. In fact, the induction of a graft versus host (GvH) or a graft versus leukemia (GvL) effect and its influence on progression-free and overall survival seem to be of possible clinical relevance. The CAR T‑cell therapy is closely linked to inflammatory reactions regarding its mode of action and the associated side effects. In this context CH might be closely linked to the effectiveness and side effects of the CAR T‑cell therapy. Initial data reported a high prevalence of CH in patients before CAR T‑cell therapy and indicated an increased rate of inflammatory side effects, although no negative effect on survival has yet been demonstrated.

Clonal Hematopoiesis Is Associated with Increased Risk of Severe Neurotoxicity in Axicabtagene Ciloleucel Therapy of Large B-Cell Lymphoma

To explore the role of clonal hematopoiesis (CH) in chimeric antigen receptor (CAR) T-cell therapy outcomes, we performed targeted deep sequencing on buffy coats collected during the 21 days before lymphodepleting chemotherapy from 114 large B-cell lymphoma patients treated with anti-CD19 CAR T cells. We detected CH in 42 (36.8%) pretreatment samples, most frequently in PPM1D (19/114) and TP53 (13/114) genes. Grade ≥3 immune effector cell-associated neurotoxicity syndrome (ICANS) incidence was higher in CH-positive patients than CH-negative patients (45.2% vs. 25.0%, P = 0.038). Higher toxicities with CH were primarily associated with DNMT3A, TET2, and ASXL1 genes (DTA mutations). Grade ≥3 ICANS (58.9% vs. 25%, P = 0.02) and ≥3 cytokine release syndrome (17.7% vs. 4.2%, P = 0.08) incidences were higher in DTA-positive than in CH-negative patients. The estimated 24-month cumulative incidence of therapy-related myeloid neoplasms after CAR T-cell therapy was higher in CH-positive than CH-negative patients [19% (95% CI, 5.5-38.7) vs. 4.2% (95% CI, 0.3-18.4), P = 0.028].

SIGNIFICANCE

Our study reveals that CH mutations, especially those associated with inflammation (DNMT3A, TET2, and ASXL1), are associated with severe-grade neurotoxicities in lymphoma patients receiving anti-CD19 CAR T-cell therapy. Further studies to investigate the mechanisms and interventions to improve toxicities in the context of CH are warranted. See related content by Uslu and June, p. 382. This article is highlighted in the In This Issue feature, p. 369.

CAR T-cell Therapy Meets Clonal Hematopoiesis

Clonal hematopoiesis of indeterminate potential (CHIP) is common in patients with hematologic malignancies. Recent publications provide evidence that CHIP may affect chimeric antigen receptor T-cell therapy efficacy and that the incidence of treatment-related toxicities such as cytokine release syndrome and immune effector-cell associated neurotoxicity syndrome may be affected. See related article by Saini et al., p. 385 (8).

Game of clones: Diverse implications for clonal hematopoiesis in lymphoma and multiple myeloma

Clonal hematopoiesis (CH) refers to the disproportionate expansion of hematopoietic stem cell clones and their corresponding progeny following the acquisition of somatic mutations. CH is common at the time of diagnosis in patients with blood cancers, including multiple myeloma (MM) and lymphoma. The presence of CH mutations correlates with IL-6 mediated inflammation and may result in lymphoma or MM modulation through microenvironment effects or by manifestations of the mutations themselves within the founding tumor clone. As might be expected with a variety of mutations and multiple potential mechanisms, CH exerts context-dependent effects, being protective in some settings and harmful in others. Though CH is very common in patients with hematologic malignancies, how it intersects with therapy and the natural disease course of these cancers are active areas of investigation. In lymphomas and MM specifically, patients have high rates of CH at diagnosis and are subsequently exposed to therapies, such as cytotoxic chemotherapy, that can cause CH progression to overt hematologic malignancy. The expanding diversity of treatment modalities for these cancers also increases the opportunities for CH to impact clinical outcome and modulate clinical responses. Here we review the basic biology and known health effects of CH, and we focus on the clinical relevance of CH in lymphoma and MM.