Late Events after Treatment with CD19-Targeted Chimeric Antigen Receptor Modified T Cells

The Emerging Role of CAR T Cell Therapy in Relapsed/Refractory Hodgkin Lymphoma

Treatment for Hodgkin lymphoma (HL) has evolved considerably from the time it was originally described in the 19th century with many patients now being cured with frontline therapy. Despite these advances, upwards of 10% of patients experience progressive disease after initial therapy with an even higher percentage relapsing. Until recently there had been limited therapeutic options for relapsed and/or refractory HL outside of highly intensive chemotherapy with stem cell rescue. Improved understanding of the pathophysiology of HL, coupled with the emergence of more targeted therapeutics, has reshaped how we view the treatment of relapsed/refractory HL and its prognosis. With this, there has been an increased focus on immunotherapies that can reprogram the immune system to better overcome the immunosuppressive milieu found in HL for improved cancer cell killing. In particular, chimeric antigen receptor (CAR) T cells are emerging as a valuable therapeutic tool in this area. Building on the success of antibody-drug conjugates directed against CD30, CAR T cells engineered to recognize the same antigen are now reaching patients. Though still in its infancy, CAR T therapy for relapsed/refractory HL has shown exceptional promise in early-stage clinical trials with the potential for durable responses even in patients who had progressed through multiple lines of prior therapy. Here we will review currently available data on the use of CAR T cells in HL, strategies to optimize their effectiveness, and how this therapy may fit into the treatment paradigm of HL going forward.

Hypogammaglobulinemia After Chimeric Antigen Receptor (CAR) T-Cell Therapy: Characteristics, Management, and Future Directions

Chimeric antigen receptor (CAR) T-cell therapy is a dynamic therapy of engineered T cells targeting neoplastic cells, which offers impressive long-term remissions for aggressive relapsed/refractory hematologic malignancies. However, side effects including severe infections can be life-threatening. Multiple factors, including cytokine release syndrome, B-cell aplasia, and hypogammaglobulinemia, contribute to infection risk. B-cell aplasia is an expected on-target, off-tumor effect of CD19⁺-targeted CAR T cells and leads to hypogammaglobulinemia. We review hypogammaglobulinemia observed in the 5 currently Food and Drug Administration-approved CAR T-cell therapies and other CAR T-cell products evaluated in clinical trials, and discuss hypogammaglobulinemia onset, duration, and immune recovery. We review associations between hypogammaglobulinemia and infections, with a discussion informed by other known B-cell-depleting contexts. Differences in hypogammaglobulinemia between children and adults are identified. We integrate management strategies for evaluation and immunoglobulin replacement from clinical studies, expert recommendations, and organizational guidelines. Notably, our review also highlights newer CAR T-cell products targeting different B-cell antigens, including B-cell maturation antigen, signaling lymphocytic activation molecule, and κ light chains. Finally, we identify key areas for future study to mitigate and treat hypogammaglobulinemia resulting from this transformative therapy.

Adverse effects in hematologic malignancies treated with chimeric antigen receptor (CAR) T cell therapy: a systematic review and Meta-analysis

Background

Recently, chimeric antigen receptor-modified (CAR) T cell therapy for hematological malignancies has shown clinical efficacy. Hundreds of clinical trials have been registered and lots of studies have shown hematologic toxic effects were very common. The main purpose of this review is to systematically analyze hematologic toxicity in hematologic malignancies treated with CAR-T cell therapy.

Methods

We searched databases including PubMed, Web of Science, Embase and Cochrane up to January 2021. For safety analysis of overall hematologic toxicity, the rate of neutrophil, thrombocytopenia and anemia were calculated. Subgroup analysis was performed for age, pathological type, target antigen, co-stimulatory molecule, history of hematopoietic stem cell transplantation (HSCT) and prior therapy lines. The incidence rate of aspartate transferase (AST) increased, alanine transaminase (ALT) increased, serum creatine increased, APTT prolonged and fibrinogen decreased were also calculated.

Results

Overall, 52 studies involving 2004 patients were included in this meta-analysis. The incidence of any grade neutropenia, thrombocytopenia and anemia was 80% (95% CI: 68–89%), 61% (95% CI: 49–73%), and 68% (95%CI: 54–80%) respectively. The incidences of grade ≥ 3 neutropenia, thrombocytopenia and anemia were 60% (95% CI: 49–70%), 33% (95% CI: 27–40%), and 32% (95%CI: 25–40%) respectively. According to subgroup analysis and the corresponding Z test, hematological toxicity was more frequent in younger patients, in patients with ≥4 median lines of prior therapy and in anti-CD19 cases. The subgroup analysis of CD19 CAR-T cell constructs showed that 41BB resulted in less hematological toxicity than CD28.

Conclusion

CAR-T cell therapy has dramatical efficacy in hematological malignancies, but the relevant adverse effects remain its obstacle. The most common ≥3 grade side effect is hematological toxicity, and some cases die from infections or severe hemorrhage in early period. In long-term follow-up, hematological toxicity is less life-threatening generally and most suffered patients recover to adequate levels after 3 months. To prevent life-threatening infections or bleeding events, clinicians should pay attention to intervention of hematological toxicity in the early process of CAR-T cell therapy.

CAR-T-OPENIA: Chimeric antigen receptor T-cell therapy-associated cytopenias

Chimeric antigen receptor (CAR) T-cell is the most recent version in the evolution of cellular therapy with promising responses, which has revolutionized the management of some hematological malignancies in the current times. As the clinical use has progressed rather rapidly since the first approval in 2017, toxicities beyond cytokine release syndrome and immune effector cell-associated neurological syndrome have surfaced. Cytopenias are common in <30 days ("early"), 30-90 days ("short-term") as well as >90 days ("prolonged"); and have clinical implications to patient care as well as resource utilization. We review the details of etiology, factors associated with cytopenias, and management considerations for patients with cytopenias for each of these time-frames. This would potentially serve as a clinical guide for hematological toxicity or CAR-T-OPENIA, which is commonly encountered with the use of CAR T-cell therapy.

Critical care management of chimeric antigen receptor T-cell therapy recipients

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapeutic treatment concept that is changing the treatment approach to hematologic malignancies. The development of CAR T-cell therapy represents a prime example for the successful bench-to-bedside translation of advances in immunology and cellular therapy into clinical practice. The currently available CAR T-cell products have shown high response rates and long-term remissions in patients with relapsed/refractory acute lymphoblastic leukemia and relapsed/refractory lymphoma. However, CAR T-cell therapy can induce severe life-threatening toxicities such as cytokine release syndrome, neurotoxicity, or infection, which require rapid and aggressive medical treatment in the intensive care unit setting. In this review, the authors provide an overview of the state-of-the-art in the clinical management of severe life-threatening events in CAR T-cell recipients. Furthermore, key challenges that have to be overcome to maximize the safety of CAR T cells are discussed.

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

Chimeric antigen receptor T-cell (CAR-T) treatment has revolutionized the landscape of cancer therapy with significant efficacy on hematologic malignancy, especially in relapsed and refractory B cell malignancies. However, unexpected serious toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) still hamper its broad application. Clinical trials using CAR-T cells targeting specific antigens on tumor cell surface have provided valuable information about the characteristics of ICANS. With unclear mechanism of ICANS after CAR-T treatment, unremitting efforts have been devoted to further exploration. Clinical findings from patients with ICANS strongly indicated existence of overactivated peripheral immune response followed by endothelial activation-induced blood-brain barrier (BBB) dysfunction, which triggers subsequent central nervous system (CNS) inflammation and neurotoxicity. Several animal models have been built but failed to fully replicate the whole spectrum of ICANS in human. Hopefully, novel and powerful technologies like single-cell analysis may help decipher the precise cellular response within CNS from a different perspective when ICANS happens. Moreover, multidisciplinary cooperation among the subjects of immunology, hematology, and neurology will facilitate better understanding about the complex immune interaction between the peripheral, protective barriers, and CNS in ICANS. This review elaborates recent findings about ICANS after CAR-T treatment from bed to bench, and discusses the potential cellular and molecular mechanisms that may promote effective management in the future. This article is categorized under: Cancer > Biomedical Engineering Immune System Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology.

CAR-T cell: Toxicities issues: Mechanisms and clinical management

CAR-T cells are modified T cells expressing a chimeric antigen receptor targeting a specific antigen. They have revolutionized the treatment of B cell malignancies (aggressive lymphomas, B-ALL), and this has raised hopes for application in many other pathologies (myeloma, AML, solid tumors, etc.). However, these therapies are associated with novel and specific toxicities (cytokine release syndrome and neurotoxicity). These complications, although mostly managed in a conventional hospitalization unit, can sometimes be life threatening, leading to admission of patients to the intensive care unit. Management relies mainly on anti-IL6R (tocilizumab) and corticosteroids. However, the optimal treatment regimen is still a matter of debate, and the management of the most severe forms is even less well codified. In addition to CRS and ICANS, infections, cytopenia and hypogammaglobulinemia are other frequent complications. This article reviews the mechanisms, risk factors, clinical presentation, and management of these toxicities.

Humoral immune reconstitution after anti-BCMA CAR T-cell therapy in relapsed/refractory multiple myeloma

Systematic and dynamic humoral immune reconstitution is little-known for patients with relapsed/refractory (R/R) multiple myeloma (MM) who received anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy. We investigated the kinetics of B-cell, normal plasma cell, and immunoglobulin recovery in 40 patients who achieved ongoing response after anti-BCMA CAR T-cell therapy. All patients developed B-cell aplasia and the median duration of B-cell aplasia was 70 days (range, 23-270). The B-cell count reached its nadir on median day 7 and returned to baseline level on median day 97. BCMA+ cells in bone marrow turned undetectable on median day 28 (13-159) in 94.87% (37 of 39) of patients. Normal plasma cells in bone marrow were first redetected on median day 212. All patients developed a significant decrease in serum IgG, IgA, and IgM on median day 60. At year 1, recovery of serum IgG, IgM, and IgA was observed in 53.33% (8 of 15; non-IgG MM), 73.08% (19 of 26; non-IgM MM), and 23.81% (5 of 21;non-IgA MM) of the patients, respectively. Median time to IgG, IgM, and IgA recovery were days 386, 254, and not reached during follow-up, respectively. Virus-specific IgG levels decreased with loss of protection. Twenty-three of 40 (57.5%) patients had a total of 44 infection events. There were no infection-related deaths. These results reveal a 7-month aplasia of bone marrow normal plasma cells and longer period of hypogammaglobulinemia, suggesting a profound and lasting humoral immune deficiency after anti-BCMA CAR T-cell therapy, especially for IgA.

Idecabtagene vicleucel (ide-cel) CAR T-cell therapy for relapsed and refractory multiple myeloma

Idecabtagene vicleucel (ide-cel), a novel chimeric antigen receptor (CAR) T-cell therapy targeting B-cell maturation antigen (BCMA), has recently gained approval by the US FDA for relapsed and refractory multiple myeloma (RRMM) after multicenter trials have demonstrated unprecedented results in this difficult-to-treat subgroup of patients. As the first CAR T-cell product approved for myeloma, ide-cel is poised to become a practice-changing treatment option. This first-in-class therapeutic offers hope for more durable remissions, as well as better quality of life, following a single infusion in a group of patients that previously had little hope. This paper reviews the ide-cel product in terms of design, pharmacology, efficacy and toxicity as described in studies reported to date.

State of the CAR-T: Risk of Infections with Chimeric Antigen Receptor T-Cell Therapy and Determinants of SARS-CoV-2 Vaccine Responses

Chimeric antigen receptor T cell (CAR-T) therapy has shown unprecedented response rates in patients with relapsed/refractory (R/R) hematologic malignancies. Although CAR-T therapy gives hope to heavily pretreated patients, the rapid commercialization and cumulative immunosuppression of this therapy predispose patients to infections for a prolonged period. CAR-T therapy poses distinctive short- and long-term toxicities and infection risks among patients who receive CAR T-cells after multiple prior treatments, often including hematopoietic cell transplantation. The acute toxicities include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. The long-term B cell depletion, hypogammaglobulinemia, and cytopenia further predispose patients to severe infections and abrogate the remission success achieved by the living drug. These on-target-off-tumor toxicities deplete B-cells across the entire lineage and further diminish immune responses to vaccines. Early observational data suggest that patients with hematologic malignancies may not mount adequate humoral and cellular responses to SARS-CoV-2 vaccines. In this review, we summarize the immune compromising factors indigenous to CAR-T recipients. We discuss the immunogenic potential of different SARS-CoV-2 vaccines for CAR-T recipients based on the differences in vaccine manufacturing platforms. Given the lack of data related to the safety and efficacy of SARS-CoV-2 vaccines in this distinctively immunosuppressed cohort, we summarize the infection risks associated with Food and Drug Administration-approved CAR-T constructs and the potential determinants of vaccine responses. The review further highlights the potential need for booster vaccine dosing and the promise for heterologous prime-boosting and other novel vaccine strategies in CAR-T recipients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Cytopenias After CD19 Chimeric Antigen Receptor T-Cells (CAR-T) Therapy for Diffuse Large B-Cell Lymphomas or Transformed Follicular Lymphoma: A Single Institution Experience

INTRODUCTION

Patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) have poor outcomes. Treatment with CD19 chimeric antigen receptor (CAR-T) cells, tisagenlecleucel and axicabtagene ciloleucel, has been associated with improved outcomes. Cytopenias were observed in clinical trials with both products; however, little is known regarding the patterns and outcomes of these cytopenias.

SUBJECTS AND METHODS

We reviewed DLBCL patients (n=32) receiving either product between January and September 2018 at our institution.

RESULTS

Median duration of leukopenia, neutropenia, lymphopenia, anemia, and thrombocytopenia was 49, 9, 117.5, 125, and 95.5 days after CAR-T infusion, respectively. Filgrastim was used in 63% of patients, and 50% of patients received red cell or platelet transfusions. With the exception of neutropenia, increase in the duration of cytopenia of any lineage was associated with improvement in progression-free survival, and in overall survival in case of anemia. There was no association between the duration of cytopenias with either cytokine release syndrome or neurotoxicity.

DISCUSSION

Our data suggest a correlation between cytopenias and survival outcomes after CD19 CAR-T therapy. If validated, cytopenia may be proven useful as a biomarker of response and survival after CAR-T therapy.

Progressive Multifocal Leukoencephalopathy After Chimeric Antigen Receptor T-Cell Therapy for Recurrent Non-Hodgkin Lymphoma

Chimeric antigen receptor (CAR) T-cell therapy targeting cluster of differentiation (CD)19 has had a transformative impact on patient outcomes in a subset of patients with relapsed/refractory non-Hodgkin lymphoma. We present a patient with refractory large B-cell lymphoma in complete remission for 2 years following treatment with CD19-targeted CAR T-cell therapy, who presented with 2 weeks of progressive aphasia. Imaging revealed a left occipital brain lesion and biopsy demonstrated features diagnostic of progressive multifocal leukoencephalopathy. Further evaluation revealed severe hypogammaglobulinemia and a low CD4 count. She was treated with pembrolizumab and intravenous immunoglobulin resulting in decreased cerebrospinal fluid viral load without clinical improvement and died 8 weeks after presentation. This case highlights that there is potential for severe opportunistic infections after CAR T-cell therapy, including fatal progressive multifocal leukoencephalopathy. Strategies to enhance post-treatment immune reconstitution are essential to further harness the unique potency of CAR T-cell therapy.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. I: Structuring centers for the multidisciplinary clinical administration and management of CAR-T cell therapy patients

Chimeric antigen receptor T-cells (CAR-T cells) are a new modality of oncological treatment which has demonstrated impressive response in refractory or relapsed diseases, such as acute lymphoblastic leukemia (ALL), lymphomas, and myeloma but is also associated with unique and potentially life-threatening toxicities. The most common adverse events (AEs) include cytokine release syndrome (CRS), neurological toxicities, such as the immune effector cell-associated neurotoxicity syndrome (ICANS), cytopenias, infections, and hypogammaglobulinemia. These may be severe and require admission of the patient to an intensive care unit. However, these AEs are manageable when recognized early and treated by a duly trained team. The objective of this article is to report a consensus compiled by specialists in the fields of oncohematology, bone marrow transplantation, and cellular therapy describing recommendations on the Clinical Centers preparation, training of teams that will use CAR-T cells, and leading clinical questions as to their use and the management of potential complications.

Management of Immune-Related Adverse Events in Patients Treated With Chimeric Antigen Receptor T-Cell Therapy: ASCO Guideline

PURPOSE

To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with chimeric antigen receptor (CAR) T-cell therapy.

METHODS

A multidisciplinary panel of medical oncology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to develop the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 to 2021.

RESULTS

The systematic review identified 35 eligible publications. Because of the paucity of high-quality evidence, recommendations are based on expert consensus.

RECOMMENDATIONS

The multidisciplinary team issued recommendations to aid in the recognition, workup, evaluation, and management of the most common CAR T-cell-related toxicities, including cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, B-cell aplasia, cytopenias, and infections. Management of short-term toxicities associated with CAR T cells begins with supportive care for most patients, but may require pharmacologic interventions for those without adequate response. Management of patients with prolonged or severe CAR T-cell-associated cytokine release syndrome includes treatment with tocilizumab with or without a corticosteroid. On the basis of the potential for rapid decline, patients with moderate to severe immune effector cell-associated neurotoxicity syndrome should be managed with corticosteroids and supportive care.Additional information is available at www.asco.org/supportive-care-guidelines.

Paraneoplastic Neuropathies: What's New Since the 2004 Recommended Diagnostic Criteria

The diagnostic criteria published by the PNS (Paraneoplastic Neurological Syndromes) Euronetwork in 2004 provided a useful classification of PNS, including paraneoplastic neuropathies. Subacute sensory neuronopathy (SSN) was the most frequently observed peripheral PNS, whereas other forms of neuropathy, as sensory polyneuropathy, sensorimotor polyneuropathy, demyelinating neuropathies, autonomic neuropathies, and focal nerve or plexus lesions, were less frequent. At the time of publication, the main focus was on onconeural antibodies, but knowledge regarding the mechanisms has since expanded. The antibodies associated with PNS are commonly classified as onconeural (intracellular) and neuronal surface antibodies (NSAbs). Since 2004, the number of antibodies and the associated tumors has increased. Knowledge has grown on the mechanisms underlying the neuropathies observed in lymphoma, paraproteinemia, and multiple myeloma. Moreover, other unrevealed mechanisms underpin sensorimotor neuropathies and late-stage neuropathies, where patients in advanced stages of cancer—often associated with weight loss—experience some mild sensorimotor neuropathy, without concomitant use of neurotoxic drugs. The spectrum of paraneoplastic neuropathies has increased to encompass motor neuropathies, small fiber neuropathies, and autonomic and nerve hyperexcitability syndromes. In addition, also focal neuropathies, as cranial nerves, plexopathies, and mononeuropathies, are considered in some cases to be of paraneoplastic origin. A key differential diagnosis for paraneoplastic neuropathy, during the course of cancer disease (the rare occurrence of a PNS), is chemotherapy-induced peripheral neuropathy (CIPN). Today, novel complications that also involve the peripheral nervous system are emerging from novel anti-cancer therapies, as targeted and immune checkpoint inhibitor (ICH) treatment. Therapeutic options are categorized into causal and symptomatic. Causal treatments anecdotally mention tumor removal. Immunomodulation is sometimes performed for immune-mediated conditions but is still far from constituting evidence. Symptomatic treatment must always be considered, consisting of both drug therapy (e.g., pain) and attempts to treat disability and neuropathic pain.

Patterns of leukocyte recovery predict infectious complications after CD19 CAR-T cell therapy in a real-world setting

Background

Adoptive immunotherapy using CD19-targeted Chimeric antigen receptor T cells (CAR-T) has revolutionized the treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Data is limited on the propensity of infections and lymphohematopoietic reconstitution after Day 30 (D30) following CAR-T cell therapy. In this study, we evaluated the prevalence and nature of infectious complications in an expanded cohort of DLBCL patients treated with CD19 CAR-T therapy and its association with the dynamics of leukocyte subpopulation reconstitution post-CAR-T cell therapy.

Methods

We conducted a retrospective study including 19 patients who received axicabtagene ciloleucel and investigated associations between cytopenia and infectious complications after D30.

Results

Nineteen patients were included, consisting of 42% Hispanic, 32% Caucasian, 21% African-American, and 5% Asian subjects. Post-D30 of CAR-T infusion, 47% patients (n=9) developed an infection and 53% (n=10) remained infection-free. The most common infection type observed was viral (7 patients) followed by bacterial (5 patients) and fungal (3 patients). Of 25 total infectious events, 56% were grade 1 or 2 and 44% were grade 3 with 10 being viral in etiology. To determine the kinetics of lymphohematopoietic reconstitution and its association with infection risk, we evaluated the relationship between cytopenias and rates of infection after D30. Notably, compared to non-infection group, infection group had a higher median absolute lymphocyte count (ALC) (1,000/µL vs. 600/µL, P<0.05), a lower median absolute neutrophil count (ANC)/ALC ratio (1.6 vs. 3.1, P<0.05) and a lower median AMC/ALC at D30 (0.37 vs. 1.67, P<0.05). In addition, we observed that only 22% of patients had recovered ANC >1,500/µL in the infection group as opposed to 70% in the non-infection group at D90 (P<0.05). Fifty-eight percent of the patients (11/19) with relapsed refractory DLBCL achieved a complete response with a median follow-up of 233 days (7.7 months).

Conclusions

Although CAR-T cell therapy is highly effective, infectious complications remain an important cause of morbidity and mortality. Low ANC/ALC and AMC/ALC ratios at D30 are potential novel predictors of infection and can be considered in future prophylactic strategies.

Toxicities associated with adoptive cellular therapies

Chimeric antigen receptor (CAR) T cell therapy is an effective strategy for the treatment of relapsed/refractory hematologic malignancies leading to the Food and Drug Administration (FDA) approval of five CAR T cell products. Despite encouraging efficacy, the widespread utilization of CAR T cell therapy is limited by unique immune mediated toxicities, primarily cytokine release syndrome (CRS) and neurologic toxicity. Data regarding late effects and long-term toxicities of CAR T cell therapy is evolving and includes prolonged cytopenias, hypogammaglobulinemia, infections and secondary malignancies. In this review, we will describe the clinical presentation, diagnosis, mechanisms and management of short- and long-term toxicities of CAR T cell therapy.

Infectious complications in relapsed refractory multiple myeloma patients after BCMA Car t-cell therapy

B-cell maturation antigen-targeted chimeric antigen receptor T cell therapy (BCMA CAR-T) is an effective treatment for relapsed refractory multiple myeloma (RRMM). However the pattern of infectious complications is not well-elucidated. We performed a single-center retrospective analysis of infection outcomes up to 1-year post BCMA CAR-T for MM from 2018-2020. Fifty-five MM patients were treated with BCMA CAR-T. Prior to lymphodepletion (LD), 35% of patients had severe hypogammaglobulinemia and 18% had severe lymphopenia. Most patients (68%) received bridging chemotherapy (BC) prior to LD. In the first month post CAR-T, 98% patients had grade 3-4 neutropenia. At 1-year post infusion, 76% patients had hypogammaglobulinemia. With a median follow-up of 6.0 months (95% CI: 4.7 to 7.4), there were a total of 47 infection events in 29 (53%) patients, 40% bacterial, 53% viral and 6% fungal. Most (92%) were mild-moderate and of the lower/upper respiratory tract system (68%). Half of infections (53%) occurred in the first 100 days post CAR-T infusion. Though no statistically significant risk factors for infection were identified, prior lines of therapy, use of BC, recent infections, and post CAR-T lymphopenia were identified as possible risk factors that need to be further explored. This is the largest study to date to assess the infectious complications post BCMA CAR-T. Despite multiple risk factors for severe immunosuppression in this cohort, relatively few life-threatening or severe infections occurred. Further larger studies are needed to better characterize the risk factors for and occurrence of infections post BCMA CAR-T.

Chimeric antigen receptor (CAR) T-cell therapy for people with relapsed or refractory diffuse large B-cell lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer of the lymphatic system. About 30% to 40% of people with DLBCL experience relapse and 10% are refractory to first-line treatment usually consisting of R-CHOP chemotherapy. Of those eligible for second-line treatment, commonly consisting of salvage chemotherapy followed by autologous stem-cell transplantation (ASCT), around 50% experience relapse. With a median overall survival of less than six to 12 months, the prognosis of individuals who relapse or are refractory (r/r) to advanced lines of treatment or of those who are ineligible for ASCT, is very poor. With the introduction of chimeric antigen receptor (CAR) T-cell therapy, a novel treatment option for these people is available.

OBJECTIVES

To assess the benefits and harms of chimeric antigen receptor (CAR) T-cell therapy for people with relapsed or refractory (r/r) DLBCL.

SEARCH METHODS

An experienced information specialist performed a systematic database search for relevant articles on CENTRAL, MEDLINE and Embase until September 11th, 2020. We also searched trial registries and reference lists of identified studies up to this date. All search results were screened by two authors independently and a third author was involved in case of discrepancies.

SELECTION CRITERIA

We included prospectively planned trials evaluating CAR T-cell therapy for people with r/r DLBCL. We had planned to include randomised controlled trials (RCTs) and we flexibly adapted eligibility criteria to the most reliable study designs available. We excluded studies involving fewer than 10 participants with r/r DLBCL and studies with a proportion of participants with r/r DLBCL below 70%, unless data were reported separately for this subgroup.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and performed risk of bias ratings independently. A third author was involved in case of disagreements. As our search did not yield any completed RCTs, prospective controlled non-randomised studies of interventions (NRSIs) or prospective observational studies with a control group, we did not meta-analyse data and reported all results narratively. We adopted the GRADE approach to assess the certainty of the evidence for prioritised outcomes.

MAIN RESULTS

We identified 13 eligible uncontrolled studies evaluating a single or multiple arms of CAR T-cell therapies. We also identified 38 ongoing studies, including three RCTs. Ten studies are awaiting classification due to completion with no retrievable results data or insufficient data to justify inclusion. The mean number of participants enrolled, treated with CAR T-cell therapy and evaluated in the included studies were 79 (range 12 to 344; data unavailable for two studies), 61 (range 12 to 294; data unavailable for one study) and 52 (range 11 to 256), respectively. Most studies included people with r/r DLBCL among people with other haematological B-cell malignancies. Participants had received at least a median of three prior treatment lines (data unavailable for four studies), 5% to 50% had undergone ASCT (data unavailable for five studies) and, except for two studies, 3% to 18% had undergone allogenic stem-cell transplantation (data unavailable for eight studies). The overall risk of bias was high for all studies, in particular, due to incomplete follow-up and the absence of blinding. None of the included studies had a control group so that no adequate comparative effect measures could be calculated. The duration of follow-up varied substantially between studies, in particular, for harms. Our certainty in the evidence is very low for all outcomes. Overall survival was reported by eight studies (567 participants). Four studies reported survival rates at 12 months which ranged between 48% and 59%, and one study reported an overall survival rate of 50.5% at 24 months. The evidence is very uncertain about the effect of CAR T-cell therapy on overall survival. Two studies including 294 participants at baseline and 59 participants at the longest follow-up (12 months or 18 months) described improvements of quality of life measured with the EuroQol 5-Dimension 5-Level visual analogue scale (EQ-5D-5L VAS) or Function Assessment of Cancer Therapy-Lymphoma (FACT-Lym). The evidence is very uncertain about the effect of CAR T-cell therapy on quality of life. None of the studies reported treatment-related mortality. Five studies (550 participants) reported the occurrence of adverse events among participants, ranging between 99% and 100% for any grade adverse events and 68% to 98% for adverse events grade ≥ 3. In three studies (253 participants), 56% to 68% of participants experienced serious adverse events, while in one study (28 participants), no serious adverse events occurred. CAR T-cell therapy may increase the risk of adverse events and serious adverse events but the evidence is very uncertain about the exact risk. The occurrence of cytokine release syndrome (CRS) was reported in 11 studies (675 participants) under use of various grading criteria. Five studies reported between 42% and 100% of participants experiencing CRS according to criteria described in Lee 2014. CAR T-cell therapy may increase the risk of CRS but the evidence is very uncertain about the exact risk. Nine studies (575 participants) reported results on progression-free survival, disease-free survival or relapse-free survival. Twelve-month progression-free survival rates were reported by four studies and ranged between 44% and 75%. In one study, relapse-free survival remained at a rate of 64% at both 12 and 18 months. The evidence is very uncertain about the effect of CAR T-cell therapy on progression-free survival. Thirteen studies (620 participants) provided data on complete response rates. At six months, three studies reported complete response rates between 40% and 45%. The evidence is very uncertain about the effect of CAR T-cell therapy on complete response rates.

AUTHORS' CONCLUSIONS

The available evidence on the benefits and harms of CAR T-cell therapy for people with r/r DLBCL is limited, mainly because of the absence of comparative clinical trials. The results we present should be regarded in light of this limitation and conclusions should be drawn very carefully. Due to the uncertainty in the current evidence, a large number of ongoing investigations and a risk of substantial and potentially life-threatening complications requiring supplementary treatment, it is critical to continue evaluating the evidence on this new therapy.

Adverse events reported to the U.S. Food and Drug Administration Adverse Event Reporting System for tisagenlecleucel

The U.S. Food and Drug Administration (FDA) approved the first chimeric antigen receptor T-cell therapy, tisagenlecleucel, in August 2017. We sought to describe adverse events (AEs) reported to the FDA Adverse Event Reporting System (FAERS) for tisagenlecleucel in the post-marketing period. We searched FAERS reports to identify U.S. patients treated with tisagenlecleucel between August 30, 2017-August 31, 2019. We reviewed individual reports, calculated AE frequencies and reporting rates (RRs), and used Empirical Bayesian Geometric Mean methods to identify disproportionate reporting. We identified 646 de-duplicated reports with a median age at AE of 18 (interquartile range: 11-56) years. The overall RR was 81.0%, and more than 95% of reports described a serious outcome. Cytokine release syndrome (CRS) was the most frequently reported AE (51.1%) with a RR of 41.4%; neurotoxicity was reported less frequently (21.2%), with a RR of 17.2%. Most disproportionately reported AEs were listed on the package insert or confounded by indication. We identified 13 subsequent neoplasms (SPN), the majority occurring within 6 months of tisagenlecleucel administration, and none reporting evidence of insertional mutagenesis. A total of 165 reports (26%) described a death outcome; most deaths occurred >30 days after treatment. The majority of deaths (64%) were due to progression of the underlying lymphoid neoplasm, and few (<5%) were attributed to CRS or neurotoxicity. We did not identify new safety concerns reported for tisagenlecleucel in the post-marketing period. Reporting rates for CRS and neurotoxicity were lower than identified in the prelicensure clinical trials.

Secondary Dysgammaglobulinemia in Children with Hematological Malignancies Treated with Targeted Therapies

Targeted therapies have emerged as innovative treatments for patients whose disease does not respond to conventional chemotherapy, and their use has widely expanded in the field of pediatric hematologic malignancies in the last decade. While they carry the promise of improved disease control and survival and are currently investigated in first-line treatment protocols for patients with poor prognostic markers, they are associated with a considerable incidence of specific toxicities, including cytokine-release syndrome, neurotoxicity, hepatotoxicity, nephrotoxicity, cardiotoxicity, endocrine adverse events, and infectious complications. Iatrogenic or secondary dysgammaglobulinemia is a main consequence of targeted therapies using monoclonal antibodies and other antibody-derived treatments that target specific antigens on lymphoid cells (blinatumomab, inotuzumab ozogamicin, rituximab), chimeric antigen receptor T cells, tyrosine kinase inhibitors (imatinib, dasatinib, nilotinib) and, to a lesser extent, checkpoint inhibitors (pembrolizumab, nivolumab). This review discusses the diagnosis and incidence of secondary or iatrogenic dysgammaglobulinemia in children treated with targeted therapies for leukemias and lymphomas, and options for monitoring and treatment.

Infectious complications of CAR T-cell therapy: a clinical update

Chimeric antigen receptor (CAR) T-cell therapy is a revolutionary treatment modality used to treat haematological malignancies. Lymphocytes are engineered to produce CARs directed towards tumour cell antigens. Clinical trials have demonstrated impressive malignancy-related outcomes. Unfortunately, numerous off-target effects can cause toxicity-related adverse events in this population, the main being cytokine release syndrome and immune effector cell neurotoxicity syndrome. This causes significant patient morbidity and poor outcomes. Patients who receive CAR T-cell therapy are also profoundly immunosuppressed and often cytopenic, which is caused by a multitude of patient- and treatment-related factors. Thus, infection-related complications are also common in this group. Indeed, up to one third of patients will suffer a serious bacterial infection in the first 30 days after therapy. Viral respiratory tract infection appears to be the most common during the late phase and can be severe; one patient has died of influenza A infection. Fungal infection and cytomegalovirus (CMV) reactivation appear to be uncommon. Although institutional guidelines on infection-prevention strategies are available, there is a dearth of evidence to support their approach. Future research needs to target important unanswered questions that remain in this patient population in order to improve their short- and long-term outcomes.

Real-World Experiences of CAR T-Cell Therapy for Large B-Cell Lymphoma: How Similar Are They to the Prospective Studies?

Chimeric antigen receptor (CAR) T cell therapy has emerged as a revolutionary treatment option for highly aggressive B cell malignancies. Clinical trials of CD19 CAR T cells for the management of relapsed and/or refractory non-Hodgkin lymphoma (NHL) have shown markedly improved survival and response rates. The goal of this review is to evaluate whether the results from these clinical trials are reflective of real-world practices through the analysis of published literature of the commercially available CAR T cell products. We have found that despite the significantly different patient characteristics, the adverse events and response rates of real-world patients were similar to those of the clinical trials. Of interest, several groups excluded from the clinical trials, such as patients with HIV infection, chronic viral hepatitis, and secondary CNS (central nervous system) lymphoma, had case reports of promising outcomes.

Pooled safety analysis of tisagenlecleucel in children and young adults with B cell acute lymphoblastic leukemia

BACKGROUND

Tisagenlecleucel, an anti-CD19 chimeric antigen receptor T cell therapy, has demonstrated efficacy in children and young adults with relapsed/refractory B cell acute lymphoblastic leukemia (B-ALL) in two multicenter phase 2 trials (ClinicalTrials.gov, NCT02435849 (ELIANA) and NCT02228096 (ENSIGN)), leading to commercialization of tisagenlecleucel for the treatment of patients up to age 25 years with B-ALL that is refractory or in second or greater relapse.

METHODS

A pooled analysis of 137 patients from these trials (ELIANA: n=79; ENSIGN: n=58) was performed to provide a comprehensive safety profile for tisagenlecleucel.

RESULTS

Grade 3/4 tisagenlecleucel-related adverse events (AEs) were reported in 77% of patients. Specific AEs of interest that occurred ≤8 weeks postinfusion included cytokine-release syndrome (CRS; 79% (grade 4: 22%)), infections (42%; grade 3/4: 19%), prolonged (not resolved by day 28) cytopenias (40%; grade 3/4: 34%), neurologic events (36%; grade 3: 10%; no grade 4 events), and tumor lysis syndrome (4%; all grade 3). Treatment for CRS included tocilizumab (40%) and corticosteroids (23%). The frequency of neurologic events increased with CRS severity (p<0.001). Median time to resolution of grade 3/4 cytopenias to grade ≤2 was 2.0 (95% CI 1.87 to 2.23) months for neutropenia, 2.4 (95% CI 1.97 to 3.68) months for lymphopenia, 2.0 (95% CI 1.87 to 2.27) months for leukopenia, 1.9 (95% CI 1.74 to 2.10) months for thrombocytopenia, and 1.0 (95% CI 0.95 to 1.87) month for anemia. All patients who achieved complete remission (CR)/CR with incomplete hematologic recovery experienced B cell aplasia; however, as nearly all responders also received immunoglobulin replacement, few grade 3/4 infections occurred >1 year postinfusion.

CONCLUSIONS

This pooled analysis provides a detailed safety profile for tisagenlecleucel during the course of clinical trials, and AE management guidance, with a longer follow-up duration compared with previous reports.

Cytokine Release Syndrome Is an Independent Risk Factor Associated With Platelet Transfusion Refractoriness After CAR-T Therapy for Relapsed/Refractory Acute Lymphoblastic Leukemia

Background: Chimeric antigen receptor T cell (CAR-T) therapy is successful in improving treatment outcomes for relapsed/refractory acute lymphoblastic leukemia (R/R ALL). However, toxicities associated with CAR-T therapy are being increasingly identified. Pancytopenia is one of the most common complications after CAR-T therapy, and platelet transfusions are an essential part of its supportive care. Study Design and Methods: This study aimed to assess the effectiveness of platelet transfusions for R/R ALL patients at our single center and identify associated risk factors. Overall, 44 R/R ALL patients were enrolled in this study, of whom 26 received CAR-T therapy and 18 received salvage chemotherapy. Result: Patients in the CAR-T group had a higher incidence of platelet transfusion refractoriness (PTR) (15/26, 57.7%) than those in the chemotherapy group (3/18, 16.7%) (p = 0.007). For patients receiving CAR-T therapy, multivariate analysis showed that the grade of cytokine release syndrome (CRS) was the only independent risk factor associated with PTR (p = 0.007). Moreover, higher peak serum IL-6 and IFN-γ levels suggested a higher risk of PTR (p = 0.024 and 0.009, respectively). Patients with PTR received more platelet infusion doses than those without PTR (p = 0.0426). Patients with PTR had more grade 3-4 bleeding events than those without PTR (21.4 vs. 0%, p = 0.230), and the cumulative incidence of grade 3-4 bleeding event was different (p = 0.023). Conclusion: We found for the first time that PTR is associated with the CRS grade. Improved knowledge on the mechanisms of PTR after CAR-T therapy is needed to design a rational therapeutic strategy that aims to improve the efficiency of transfusions.

How I treat adverse effects of CAR-T cell therapy

Chimeric antigenreceptor (CAR) T cell therapy has demonstrated efficacy in B cell malignancies, particularly for acute lymphoblastic leukaemia (ALL) and non‑Hodgkin lymphomas. However, this regimen is not harmless and, in some patients, can lead to a multi organ failure. For this reason, the knowledge and the early recognition and management of the side effects related to CAR-T cell therapy for the staff is mandatory. In this review, we have summarised the current recommendations for the identification, gradation and management of the cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, as well as infections, and related to CAR-T cell therapy.

Thrombopoietin receptor agonists for acquired thrombocytopenia following anti-CD19 CAR-T-cell therapy: a case report

Chimeric antigen receptor (CAR)-modified T-cells targeting CD19 represent a promising therapy for relapsed or refractory (r/r) lymphoma and leukemia. The most common adverse events are immune related and include cytokine release syndrome and neurotoxicity. However, early and late hematological toxicity has emerged as a substantial clinical hurdle leading among others to an increased risk for infections or bleeding. The underlying pathophysiology remains elusive and supportive measures comprise stem cell support or the use of growth factors. Here, we report a 66-year-old woman with r/r diffuse large B-cell lymphoma that received anti-CD19 CAR-T-cells achieving a complete metabolic remission. At month 3 after adoptive cell transfer, the patient still exhibited a grade 3 anemia and a grade 4 thrombocytopenia. The latter required regular platelet transfusions. Bone marrow smear revealed hypocellularity without dysplasia. Despite reduced megakaryopoiesis, immature platelet fraction was elevated indicating an at least partially consumptive underlying component. Based on the successful use of Romiplostim, a thrombopoietin receptor-agonist, in aplastic anemia and immune thrombocytopenia, we treated our patient accordingly. Platelet count (and hemoglobin levels) increased and the patient remains transfusion-free. Taken together, our therapeutic approach could represent a novel strategy for managing CAR-T-cell-related hematotoxicity but, self-evidently, requires further controlled clinical studies.

Infections after anti-CD19 chimeric antigen receptor T-cell therapy for hematologic malignancies: timeline, prevention, and uncertainties

PURPOSE OF REVIEW

Data on the infectious complications of anti-CD19 chimeric antigen receptor-modified T-cell (CAR-T-cell) therapies are scant. The approaches to preventing and managing infections among CAR-T-cell recipients are extrapolated from those of patients with other hematological malignancies. Understanding the incidence and risk factors of infections in these patients will improve clinical outcomes.

RECENT FINDINGS

Infections occur in 23-42% of CAR-T-cell recipients and are most frequent in the first month after infusion, declining sharply thereafter. Risk factors include preinfusion (e.g., prior hematopoietic cell transplant, underlying malignancy) and postinfusion variables (e.g., cytokine release syndrome [CRS], neutropenia). Neutropenic fever after CAR-T-cell therapy is nearly universal but is confounded by CRS. The timeline of infections can be divided into preinfusion (because of the preparative regimen); 0-30 days after infusion, when bacterial infections predominate; and 30 days onwards, when respiratory viral infections predominate. Fungal and herpesviridae infections are uncommon.

SUMMARY

Recent studies have shed light on the epidemiology of infections after CAR-T-cell therapy. Future efforts should focus on identifying modifiable risk factors for infection, defining neutropenic fever in the setting of CRS, determining the benefit of antimold prophylaxis, and identifying the optimal approach to viral monitoring, vaccination, and immunoglobulin replacement.

Central nervous system injury from novel cancer immunotherapies

PURPOSE OF REVIEW

Neurotoxicity from antineoplastic treatment remains a challenge in oncology. Cancer treatment-induced central nervous system (CNS) injury can be therapy-limiting, severely disabling, and even fatal. While emerging cancer immunotherapies have revolutionized oncology during the past decade, their immunomodulatory properties can cause immune-related adverse effects (IRAE) across organ systems, including the nervous system. Central neurologic IRAEs from chimeric antigen receptor T cells (CAR-T) and immune checkpoint inhibitors (ICPI) are challenging complications of such therapies.We aim to provide clinicians with a comprehensive review of the relevant forms of CAR-T and ICPI-associated CNS toxicity, focusing on clinical features of such complications, diagnostic workup, predictive biomarkers, and management considerations in affected patients.

RECENT FINDINGS

Unique forms of CAR-T and ICPI-related CNS toxicity have been characterized in the recent literature. CAR-T-related neurotoxicity is common and clinically well delineated. ICPI-related CNS toxicity is relatively rare but includes a heterogenous spectrum of severe and diagnostically challenging conditions. While putative risk factors, neurotoxicity biomarkers, imaging correlates and treatment strategies have been put forward, development of tailored diagnostic and management consensus guidelines awaits further clinical investigation.

SUMMARY

As CAR-T and ICPI become more widely adopted, early recognition, documentation, and management of immunotherapy-related CNS toxicity are of paramount importance in the clinical setting.

CAR-HEMATOTOX: A model for CAR T-cell related hematological toxicity in relapsed/refractory large B-cell lymphoma

Hematotoxicity represents a frequent chimeric antigen receptor (CAR) T-cell related adverse event and remains poorly understood. In this multicenter analysis, we studied patterns of hematopoietic reconstitution and evaluated potential predictive markers in 258 patients receiving Axicabtagene ciloleucel (Axi-cel) or Tisagenlecleucel (Tisa-cel) for relapsed/refractory large B-cell lymphoma. We observed profound (ANC<100/µl) and prolonged (≥day 21) neutropenia in 72 and 64% of patients respectively. The median duration of severe neutropenia (ANC<500/µl) was 9 days. We aimed to identify predictive biomarkers of hematotoxicity using the duration of severe neutropenia until day +60 as the primary endpoint. In the training cohort (n=58), we observed a significant correlation with baseline thrombocytopenia (r= -0.43, P=0.001) and hyperferritinemia (r=0.54, P<0.0001) on uni- and multivariate analysis. Incidence and severity of CRS, ICANS and peak cytokine levels were not associated with the primary endpoint. We calculated the CAR-HEMATOTOX model, which included markers associated with hematopoietic reserve (e.g. platelet count, hemoglobin and ANC) and baseline inflammation (e.g. C-reactive-protein, ferritin). This model was validated in two independent cohorts from Europe (n=91) and the USA (n=109), and discriminated patients with severe neutropenia ≥/<14 days (pooled validation: AUC=0.89, Sensitivity 89%, Specificity 68%). A high CAR-HEMATOTOX score resulted in a longer duration of neutropenia (12 vs. 5.5 days, P<0.001), and a higher incidence of severe thrombocytopenia (87% vs. 34%, P<0.001) and anemia (96% vs. 40%, P<0.001). The score implicates pre-CART bone marrow reserve and inflammatory state as key features associated with delayed cytopenia and will be useful for risk-adapted management of hematotoxicity.

Incidence and Risk Factors Associated with Infection after Chimeric Antigen Receptor T Cell Therapy for Relapsed/Refractory B-cell Malignancies

Chimeric antigen receptor T cells (CAR-Ts) constitute a novel therapeutic strategy for relapsed/refractory B-cell malignancies. With the extensive application of CAR-T therapy in clinical settings, CAR-T-associated toxicities have become increasingly apparent. However, information regarding the associated infections is limited. We aimed to evaluate the incidence of infection during CAR-T therapy and identify the potential risk factors. Especially, we evaluated infections and the associated risk factors in 92 patients. The cohort included patients with acute lymphoblastic leukemia (n = 58) and non-Hodgkin lymphoma (n = 34). Fifteen cases of infection (predominantly bacterial) were observed within 28 days of CAR-T therapy, with an infection density of 0.5 infections for every 100 days-at-risk. Neutropenia before CAR-T therapy (P = .005) and prior infection (P = .046) were independent risk factors associated with infection within 28 days after CAR-T therapy; corticosteroid treatment during cytokine release syndrome (P = .013) was an independent risk factor during days 29-180 after CAR-T infusions. Moreover, the 2-year survival duration was significantly shorter in patients with infections than in those without (126 vs 409 days; P = .006). Our results suggested that effective anti-infection therapies may improve prognosis of patients who have a high infection risk. The risk of bacterial infections during the early stages of CAR-T therapy and the subsequent risk of viral infections thereafter should be considered to provide the appropriate treatment and improve patient prognosis.

Antibodies against vaccine-preventable infections after CAR-T cell therapy for B cell malignancies

BACKGROUND

Little is known about pathogen-specific humoral immunity after chimeric antigen receptor–modified T (CAR-T) cell therapy for B cell malignancies.

METHODS

We conducted a prospective cross-sectional study of CD19-targeted or B cell maturation antigen–targeted (BCMA-targeted) CAR-T cell therapy recipients at least 6 months posttreatment and in remission. We measured pathogen-specific IgG against 12 vaccine-preventable infections and the number of viral and bacterial epitopes to which IgG was detected (“epitope hits”) using a serological profiling assay. The primary outcome was the proportion of participants with IgG levels above a threshold correlated with seroprotection for vaccine-preventable infections.

RESULTS

We enrolled 65 children and adults a median of 20 months after CD19- (n = 54) or BCMA- (n = 11) CAR-T cell therapy. Among 30 adults without IgG replacement therapy (IGRT) in the prior 16 weeks, 27 (90%) had hypogammaglobulinemia. These individuals had seroprotection to a median of 67% (IQR, 59%–73%) of tested infections. Proportions of participants with seroprotection per pathogen were comparable to population-based studies, but most individuals lacked seroprotection to specific pathogens. Compared with CD19-CAR-T cell recipients, BCMA-CAR-T cell recipients were half as likely to have seroprotection (prevalence ratio, 0.47; 95% CI, 0.18–1.25) and had fewer pathogen-specific epitope hits (mean difference, –90 epitope hits; 95% CI, –157 to –22).

CONCLUSION

Seroprotection for vaccine-preventable infections in adult CD19-CAR-T cell recipients was comparable to the general population. BCMA-CAR-T cell recipients had fewer pathogen-specific antibodies. Deficits in both groups support the need for vaccine and immunoglobulin replacement therapy studies.

FUNDING

Swiss National Science Foundation (Early Postdoc Mobility grant P2BSP3_188162), NIH/National Cancer Institute (NIH/NCI) (U01CA247548 and P01CA018029), NIH/NCI Cancer Center Support Grants (P30CA0087-48 and P30CA015704-44), American Society for Transplantation and Cellular Therapy, and Juno Therapeutics/BMS.

In this prospective study, we investigated antibodies against vaccine-preventable infections and other pathogen-specific antibodies in individuals with remission after CAR-T cell therapy for B lineage malignancies.

Beyond the storm - subacute toxicities and late effects in children receiving CAR T cells

As clinical advances with chimeric antigen receptor (CAR) T cells are increasingly described and the potential for extending their therapeutic benefit grows, optimizing the implementation of this therapeutic modality is imperative. The recognition and management of cytokine release syndrome (CRS) marked a milestone in this field; however, beyond the understanding gained in treating CRS, a host of additional toxicities and/or potential late effects of CAR T cell therapy warrant further investigation. A multicentre initiative involving experts in paediatric cell therapy, supportive care and/or study of late effects from cancer and haematopoietic stem cell transplantation was convened to facilitate the comprehensive study of extended CAR T cell-mediated toxicities and establish a framework for new systematic investigations of CAR T cell-related adverse events. Together, this group identified six key focus areas: extended monitoring of neurotoxicity and neurocognitive function, psychosocial considerations, infection and immune reconstitution, other end organ toxicities, evaluation of subsequent neoplasms, and strategies to optimize remission durability. Herein, we present the current understanding, gaps in knowledge and future directions of research addressing these CAR T cell-related outcomes. This systematic framework to study extended toxicities and optimization strategies will facilitate the translation of acquired experience and knowledge for optimal application of CAR T cell therapies.

The Potential Role of the Intestinal Micromilieu and Individual Microbes in the Immunobiology of Chimeric Antigen Receptor T-Cell Therapy

Cellular immunotherapy with chimeric antigen receptor (CAR)-T cells (CARTs) represents a breakthrough in the treatment of hematologic malignancies. CARTs are genetically engineered hybrid receptors that combine antigen-specificity of monoclonal antibodies with T cell function to direct patient-derived T cells to kill malignant cells expressing the target (tumor) antigen. CARTs have been introduced into clinical medicine as CD19-targeted CARTs for refractory and relapsed B cell malignancies. Despite high initial response rates, current CART therapies are limited by a long-term loss of antitumor efficacy, the occurrence of toxicities, and the lack of biomarkers for predicting therapy and toxicity outcomes. In the past decade, the gut microbiome of mammals has been extensively studied and evidence is accumulating that human health, apart from our own genome, largely depends on microbes that are living in and on the human body. The microbiome encompasses more than 1000 bacterial species who collectively encode a metagenome that guides multifaceted, bidirectional host-microbiome interactions, primarily through the action of microbial metabolites. Increasing knowledge has been accumulated on the role of the gut microbiome in T cell-driven anticancer immunotherapy. It has been shown that antibiotics, dietary components and gut microbes reciprocally affect the efficacy and toxicity of allogeneic hematopoietic cell transplantation (allo HCT) as the prototype of T cell-based immunotherapy for hematologic malignancies, and that microbiome diversity metrics can predict clinical outcomes of allo HCTs. In this review, we will provide a comprehensive overview of the principles of CD19-CART immunotherapy and major aspects of the gut microbiome and its modulators that impact antitumor T cell transfer therapies. We will outline i) the extrinsic and intrinsic variables that can contribute to the complex interaction of the gut microbiome and host in CART immunotherapy, including ii) antibiotic administration affecting loss of colonization resistance, expansion of pathobionts and disturbed mucosal and immunological homeostasis, and ii) the role of specific gut commensals and their microbial virulence factors in host immunity and inflammation. Although the role of the gut microbiome in CART immunotherapy has only been marginally explored so far, this review may open a new chapter and views on putative connections and mechanisms.

[Toxicity after chimeric antigen receptor T-cell therapy : Overview and management of early and late onset side effects]

BACKGROUND

The transfusion of chimeric antigen receptor (CAR) T‑cells has become established as a new treatment option in oncology; however, this is regularly associated with immune-mediated side effects, which can also run a severe course and necessitate a specific treatment and intensive medical treatment.

MATERIAL AND METHODS

A literature review was carried out on CAR T-cell therapy, toxicities and the management of side effects.

RESULTS

The cytokine release syndrome (CRS) and the immune effector cell-associated neurotoxicity syndrome (ICANS) regularly occur shortly after CAR T-cell treatment. The symptoms of CRS can range from mild flu-like symptoms to multiorgan failure. In addition to mild symptoms, such as disorientation and aphasia, ICANS can also lead to convulsive seizures and brain edema. The management of CRS and ICANS is based on the severity according to the grading of the American Society for Transplantation and Cellular Therapy (ASTCT). Tocilizumab and corticosteroids are recommended for CRS and corticosteroids are used for ICANS. In the further course persisting hypogammaglobulinemia and cytopenia are frequent even months after the initial treatment and promote infections even months after CAR T‑cell therapy.

DISCUSSION

Potentially severe complications regularly occur after CAR T-cell therapy. An interdisciplinary cooperation between intensive care physicians, hematologists, neurologists and specialists in other disciplines is of decisive importance for the optimal care of patients after CAR T‑cell therapy.

DLBCL patients treated with CD19 CAR T cells experience a high burden of organ toxicities but low nonrelapse mortality

Cytokine release syndrome (CRS) immune effector cell-associated neurotoxicity syndrome are the most notable toxicities of CD19 chimeric antigen receptor (CAR) T-cell therapy. In addition, CAR T-cell-mediated toxicities can involve any organ system, with varied impacts on outcomes, depending on patient factors and involved organs. We performed detailed analysis of organ-specific toxicities and their association with outcomes in 60 patients with diffuse large B-cell lymphoma (DLBCL) treated with CD19 CAR T cells by assessing all toxicities in organ-based groups during the first year posttreatment. We observed 539 grade ≥2 and 289 grade ≥3 toxicities. Common grade ≥3 toxicities included hematological, metabolic, infectious, and neurological complications, with corresponding 1-year cumulative incidence of 57.7%, 54.8%, 35.4%, and 18.3%, respectively. Patients with impaired performance status had a higher risk of grade ≥3 metabolic complications, whereas elevated lactate dehydrogenase was associated with higher risks of grade ≥3 neurological and pulmonary toxicities. CRS was associated with higher incidence of grade ≥3 metabolic, pulmonary, and neurologic complications. The 1-year nonrelapse mortality and overall survival were 1.7% and 69%, respectively. Only grade ≥3 pulmonary toxicities were associated with an increased mortality risk. In summary, toxicity burdens after CD19 CAR T-cell therapy were high and varied by organ systems. Most toxicities were manageable and were rarely associated with mortality. Our study emphasizes the importance of toxicity assessment, which could serve as a benchmark for further research to reduce symptom burdens and improve tolerability in patients treated with CAR T cells.

Hematopoietic recovery in patients receiving chimeric antigen receptor T-cell therapy for hematologic malignancies

Factors contributing to hematopoietic recovery following chimeric antigen receptor (CAR) T-cell therapy have not been well studied. In an analysis of 83 patients with hematologic malignancies treated with CAR T-cell therapy, we describe patterns of hematopoietic recovery and evaluate potentially associated factors. We included patients who received axicabtagene ciloleucel (n = 30) or tisagenlecleucel (n = 10) for B-cell lymphoma, CD19-28z CAR T therapy for B-cell acute lymphoblastic leukemia (NCT01044069; n = 37), or B-cell maturation antigen targeting CAR T cells for multiple myeloma (NCT03070327; n = 6). Patients treated with CAR T cells who had not progressed, died, or received additional chemotherapy had "recovered" (per definition in Materials and methods section) hemoglobin, platelet, neutrophil, and white blood cell counts at rates of 61%, 51%, 33%, and 28% at month 1 postinfusion and 93%, 90%, 80%, and 59% at month 3 postinfusion, respectively. Univariate analysis showed that increasing grade of immune effector cell-associated neurological syndrome (ICANS), baseline cytopenias, CAR construct, and higher peak C-reactive protein or ferritin levels were statistically significantly associated with a lower likelihood of complete count recovery at 1 month; a similar trend was seen for cytokine release syndrome (CRS). After adjustment for baseline cytopenia and CAR construct, grade ≥3 CRS or ICANS remained significantly associated with the absence of complete count recovery at 1 month. Higher levels of vascular endothelial growth factor and macrophage-derived chemokines, although not statistically significant, were seen patients without complete count recovery at 1 month. This remains to be studied further in larger prospective studies.

Immune reconstitution and infectious complications following axicabtagene ciloleucel therapy for large B-cell lymphoma

Chimeric antigen receptor (CAR) T-cell therapy targeting CD19 has significantly improved outcomes in the treatment of refractory or relapsed large B-cell lymphoma (LBCL). We evaluated the long-term course of hematologic recovery, immune reconstitution, and infectious complications in 41 patients with LBCL treated with axicabtagene ciloleucel (axi-cel) at a single center. Grade 3+ cytopenias occurred in 97.6% of patients within the first 28 days postinfusion, with most resolved by 6 months. Overall, 63.4% of patients received a red blood cell transfusion, 34.1% of patients received a platelet transfusion, 36.6% of patients received IV immunoglobulin, and 51.2% of patients received growth factor (granulocyte colony-stimulating factor) injections beyond the first 28 days postinfusion. Only 40% of patients had recovered detectable CD19+ B cells by 1 year, and 50% of patients had a CD4+ T-cell count <200 cells per μL by 18 months postinfusion. Patients with durable responses to axi-cel had significantly longer durations of B-cell aplasia, and this duration correlated strongly with the recovery of CD4+ T-cell counts. There were significantly more infections within the first 28 days compared with any other period of follow-up, with the majority being mild-moderate in severity. Receipt of corticosteroids was the only factor that predicted risk of infection in a multivariate analysis (hazard ratio, 3.69; 95% confidence interval, 1.18-16.5). Opportunistic infections due to Pneumocystis jirovecii and varicella-zoster virus occurred up to 18 months postinfusion in patients who prematurely discontinued prophylaxis. These results support the use of comprehensive supportive care, including long-term monitoring and antimicrobial prophylaxis, beyond 12 months after axi-cel treatment.

Humoral immunogenicity of the seasonal influenza vaccine before and after CAR-T-cell therapy

Recipients of chimeric antigen receptor-modified T (CAR-T) cell therapies for B-cell malignancies are immunocompromised and at risk for serious infections. Vaccine immunogenicity is unknown in this population. We conducted a prospective observational study of the humoral immunogenicity of 2019-2020 inactivated influenza vaccines (IIV) in children and adults immediately prior to (n=7) or 13-57 months after (n=15) CD19-, CD20-, or BCMA-targeted CAR-T-cell therapy, as well as controls (n=8). Individuals post-CAR-T-cell therapy were in remission. We tested for antibodies to 4 vaccine strains at baseline and ≥1 time point after IIV using neutralization and hemagglutination inhibition assays. An antibody response was defined as a ≥4-fold titer increase from baseline at the first post-vaccine time point. Baseline A(H1N1) titers in the CAR-T cohorts were significantly lower compared to controls. Antibody responses to ≥1 vaccine strain occurred in 2 (29%) individuals before CAR-T-cell therapy; one individual maintained a response for >3 months post-CAR-T-cell therapy. Antibody responses to ≥1 vaccine strain occurred in 6 (40%) individuals vaccinated after CAR-T-cell therapy. An additional 2 (29%) and 6 (40%) individuals had ≥2-fold increases (at any time) in the pre- and post-CAR-T cohorts, respectively. There were no identified clinical or immunologic predictors of antibody responses. Neither severe hypogammaglobulinemia nor B-cell aplasia precluded antibody responses. These data support consideration for vaccination before and after CAR-T-cell therapy for influenza and other relevant pathogens such as SARS-CoV-2, irrespective of hypogammaglobulinemia or B-cell aplasia. Larger studies are needed to determine correlates of vaccine immunogenicity and durability in CAR-T-cell therapy recipients.

Key Points

Influenza vaccination was immunogenic pre- and post-CAR-T-cell therapy, despite hypogammaglobulinemia and B-cell aplasia.Vaccination with inactivated vaccines can be considered before CAR-T-cell therapy and in individuals with remission after therapy.

Infections associated with the new 'nibs and mabs' and cellular therapies

PURPOSE OF REVIEW

In recent years, we have witnessed a remarkable surge in the clinical development of effective biological and cellular therapies for the treatment of neoplastic and autoimmune disorders. The present review summarizes our understanding of the pathogen-specific infection risk associated with the use of such therapies.

RECENT FINDINGS

A variety of biologics, in the form of either monoclonal antibodies (Mabs) or small molecule kinase inhibitors (Nibs), are continuously introduced in the clinic for the management of autoimmune and malignant diseases. In addition, cellular therapies such as the infusion of chimeric antigen receptor (CAR) T-cells are becoming increasingly available for patients with treatment-refractory lymphoid malignancies. Some of these biological and cellular interventions exert direct or indirect adverse effects on the induction of protective immune responses against various pathogens, resulting in heightened infection susceptibility.

SUMMARY

The introduction of biological and cellular therapies for the treatment of malignant and autoimmune diseases has been associated with increased infection susceptiblity, which varies greatly depending on the specific immunomodulatory therapy, the infecting pathogen and the recipient patient population. A high index of clinical suspicion and efforts aiming at early diagnosis, targeted vaccination or prophylaxis, and prompt initiation of antimicrobial treatment should help improve infection outcomes.

An owner's manual for CD19 "CAR"-T cell therapy in managing pediatric and young adult B-cell acute lymphoblastic leukemia

Despite excellent cure rates in newly diagnosed patients with B-cell acute lymphoblastic leukemia (B-ALL), therapies that improve outcomes for children with relapsed or refractory (r/r) B-ALL are needed. Chimeric antigen receptor (CAR)-T cell therapy has demonstrated durable responses and a manageable safety profile in children, adolescents, and young adults less than 26 years old with r/r B-ALL, including patients who have relapsed after allogeneic stem cell transplant. This comprehensive review summarizes current data, management practices, and future directions for the treatment of r/r B-ALL in pediatric and young adult patients with CAR-T cell therapy, including patient selection, patient preparation, and CAR-T cell infusion, as well as monitoring and management of short- and long-term safety events, long-term surveillance, and survivorship. Clinical trials registration number: N/A.

Cardiovascular Toxicities of CAR T-cell Therapy

PURPOSE OF REVIEW

This review provides a contemporary overview of current studies outlining the incidence and characteristics of CAR T-cell cardiotoxicity in an effort to identify future directions for research and potential opportunities for prevention and intervention.

RECENT FINDINGS

Cardiovascular events occurred in anywhere between 10 and 36% of patients in CAR T-cell clinical trials, ranging from tachycardia, hypotension, arrhythmia, decreased left ventricular systolic function to cardiogenic shock and death. Cardiac events are more often associated higher grades (> 2) of cytokine release syndrome and frequently proceeded by an elevated troponin. There is a growing recognition of cardiotoxicities of CAR T-cell therapy but has a limited study in this area. The mechanism of left ventricular dysfunction due to CAR T-cell therapy is also unknown. As CAR T-cell use expands, it becomes imperative to truly understand the mechanism behind cardiac injury and to assess long-term follow-up data as this will allow for surveillance, early intervention, and potentially prevention of cardiotoxicity.

Reactions Related to CAR-T Cell Therapy

The application of chimeric antigen receptor (CAR) T-cell therapy as a tumor immunotherapy has received great interest in recent years. This therapeutic approach has been used to treat hematological malignancies solid tumors. However, it is associated with adverse reactions such as, cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), off-target effects, anaphylaxis, infections associated with CAR-T-cell infusion (CTI), tumor lysis syndrome (TLS), B-cell dysplasia, hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) and coagulation disorders. These adverse reactions can be life-threatening, and thus they should be identified early and treated effectively. In this paper, we review the adverse reactions associated with CAR-T cells, the mechanisms driving such adverse reactions, and strategies to subvert them. This review will provide important reference data to guide clinical application of CAR-T cell therapy.

CAR T cells Targeting Human Immunoglobulin Light Chains Eradicate Mature B-cell Malignancies While Sparing a Subset of Normal B Cells

PURPOSE

CD19-redirected chimeric antigen receptor (CAR.CD19) T cells promote clinical responses in patients with relapsed/refractory B-cell non-Hodgkin lymphomas and chronic lymphocytic leukemia (CLL). However, patients showing sustained clinical responses after CAR.CD19-T treatment show increased infection risk due to compromised B-lymphocyte recovery. Mature B cell-derived malignancies express monoclonal immunoglobulins bearing either κ- or λ-light chains. We initially constructed CAR-T targeting the κ-light-chain (CAR.κ) and established a clinical study with it. After optimizing the CAR molecule, cells developed CAR-T targeting the λ-light chain (CAR.λ) and we explored their antitumor activity.

EXPERIMENTAL DESIGN

Using Igλ⁺ lymphoma cell lines and patient-derived Igλ⁺ CLL cells, we evaluated the in vitro tumor cytotoxicity and cytokine profiles of CAR.λ. We also assessed the in vivo efficacy of CAR.λ in xenograft Igλ⁺ lymphoma models including a patient-derived xenograft (PDX) of mantle cell lymphoma, and the effects of λ- or κ-light chain-specific CAR-T on normal B lymphocytes in a humanized murine model.

RESULTS

CAR.λ demonstrated antitumor effects against Igλ⁺ lymphoma cells and patient-derived CLL cells in vitro, and in vivo in xenograft and PDX Igλ⁺ lymphoma murine models. Antitumor activity of CAR.λ was superimposable to CAR.CD19. Furthermore, we demonstrated in the humanized murine model that λ- or κ-light chain-specific CAR-T cells only depleted the corresponding targeted light chain-expressing normal B cells, while sparing the reciprocal light chain carrying B cells.

CONCLUSIONS

Adoptive transfer of CAR.λ and CAR.κ-T cells represents a useful and alternative modality to CAR.CD19-T cells in treating mature B-cell malignancies with minimal impact on humoral immunity.

Infection Complications after Lymphodepletion and Dosing of Chimeric Antigen Receptor T (CAR-T) Cell Therapy in Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia or B Cell Non-Hodgkin Lymphoma

Chimeric antigen receptor T (CAR-T) cell therapy has proven to be very effective in patients with relapsed/refractory acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL). However, infections-related either due to lymphodepletion or the CAR-T cell therapy itself-can result in severe and potentially life-threatening complications, while side effects such as cytokine release syndrome (CRS) might complicate differential diagnosis. Sixty-seven dosings of CAR-T cells in sixty adult patients with NHL (85%) and ALL (15%) receiving CAR-T cell therapy were assessed for infectious complications. Almost two-thirds of patients (61%) developed fever following lymphodepletion and CAR-T cell dosing. Microbiological or radiological findings were observed in 25% of all cases (bacterial 12%, viral 5%, fungal 8%). Inpatient infections were associated with more lines of therapy and more severe CRS. However, overall serious complications were rare after CAR-T therapy, with one patient dying of infection. Pathogen detection after inpatient stay was infrequent and mostly occurred in the first 90 days after dosing. Infections in CAR-T cell treated patents are common. Fast and suitable identification and treatment are crucial in these heavily pretreated and immunocompromised patients. In most cases infectious complications are manageable. Nonetheless, standardized anti-infective prophylaxis and supportive therapy are mandatory to reduce morbidity and mortality in CAR-T cell therapy.