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

Cytokine Release Syndrome After CAR T-Cell Therapy in a 35-Year-Old Patient With Pneumocystis jiroveci Pneumonia and Cytomegalovirus Viremia

Background: The risk of cytokine release syndrome (CRS) in patients with infections prior to chimeric antigen receptor T-cell (CAR T-cell) therapy represents an important and underreported event. Patients with active infections needing prompt CAR T-cell therapy to treat aggressive hematologic malignancies remain a clinical challenge. Case Report: This case describes the clinical course of a 35-year-old male patient with relapsed/refractory T-cell/histiocyte-rich large B-cell lymphoma who received axicabtagene ciloleucel. The patient developed ASTCT Grade II CRS on day +5, necessitating hospital admission and intravenous antibiotics, dexamethasone and tocilizumab. The patient was found to have a Pneumocystis jirovecii pneumonia (PJP) infection 3 days prior to CAR T-cell infusion and cytomegalovirus (CMV) viremia 3 days after CAR T-cell infusion. He received TMP-SMX for 21 days to treat PJP and valganciclovir to treat CMV viremia. PET/CT on day +26 demonstrated near resolution of pulmonary nodules and significant partial response of disease according to Deauville criteria. Conclusion: This case highlights the risk of CRS in immunocompromised patients with infections, and presents a unique case of CRS associated with PJP and CMV infections. Although the patient's clinical course was fraught with complications, he achieved a significant partial response to CAR T-cell therapy with the help of a multidisciplinary medical team.

Immune reconstitution and evolution of B-cell-stimulating cytokines after R-CHOP therapy for HIV-associated DLBCL

ABSTRACT

HIV infection is associated with an increased risk of diffuse large B-cell lymphoma (DLBCL). In this prospective study, we analyzed the evolution of B-cell activating cytokines (interleukin-6 [IL-6], IL-10, and B-cell activating factor [BAFF]) and main functional subsets of circulating B and T cells in 51 patients with HIV-associated DLBCL treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, Oncovin [vincristine], and prednisone). R-CHOP therapy was associated with a decrease of IL-10, whereas IL-6 levels fluctuated, and BAFF levels increased during the first 3 months and decreased thereafter. We observed a rapid rise in CD19+ B cells composed mostly of naïve B cells whereas marginal zone-like B cells and memory B cells recovered gradually. With a median follow-up of 41 months, progression-free survival and overall survival at 5 years were 61.8% (95% confidence interval [CI], 47.6-80.4) and 67.4% (95% CI, 53.4-85.0), respectively. Progression (17.5%) and sepsis (12.5%) were the main causes of death. Baseline risk factors for death and progression were poor revised International Prognostic Index (P = .049), natural killer cell lymphopenia (P = .001), lower proportion of naïve B cells (P = .017), and higher IL-6 serum levels (P = .001). Our data suggest that patients treated with R-CHOP for HIV-associated DLBCL have a disturbed peripheral B-cell compartment and that the low pool size of circulating naïve B cells negatively affects their clinical outcome. In an era of development of B-cell-depleting therapies including B-cell-targeting chimeric antigen receptor T cells, assessment of perturbations within nontumoral B-cell counterparts are warranted for risk profiling in HIV-associated DLBCL. This trial was registered at www.ClinicalTrials.gov as #NCT01164436.

Mitigating and managing infection risk in adults treated with CAR T-cell therapy

Chimeric antigen receptor T-cell therapy (CAR-T) has transformed the treatment paradigm of relapsed/refractory B-cell malignancies. Yet, this therapy is not without toxicities. While the early inflammation-mediated toxicities are now better understood, delayed hematopoietic recovery and infections result in morbidity and mortality risks that persist for months following CAR-T. The predisposition to infections is a consequence of immunosuppression from the underlying disease, prior therapies, lymphodepletion chemotherapy, delayed hematopoietic recovery, B-cell aplasia, and delayed T-cell immune reconstitution. These risks and epidemiology can vary over a post-CAR-T timeline of early (<30 days), prolonged (30-90 days), or late (>90 days) follow-up. Antibacterial, antiviral, and antifungal prophylaxis; growth factors and stem cell boost to expedite count recovery; immunoglobulin replacement therapy; and possibly revaccination programs are important prevention strategies to consider for infection mitigation. Assessment of risk factors, evaluation, and treatment for pathogen(s) prevalent in a particular time frame post-CAR-T are important clinical considerations in patients presenting with clinical features suggestive of infectious pathology. As more data emerge on the topic, personalized risk assessments to inform the type and duration of prophylaxis use and planning interventions will continue to emerge. Herein, we review our current approach toward infection mitigation while recognizing that this continues to evolve and that there are differences among practices stemming from data availability limitations.

Late complications and long-term care of adult CAR T-cell patients

The success of chimeric antigen receptor (CAR) T-cell therapy in adult patients with hematologic malignancies has resulted in a large number of long-term survivors who may experience late complications distinct from those in the early CAR T-cell treatment period. These late complications, defined as occurring more than 90 days after CAR T-cell infusion, include cytopenias, infections, secondary malignancies, and delayed neurotoxicities. Late cytopenias may be from prolonged recovery after lymphodepleting (LD) chemotherapy or arise anew, raising concerns for recurrent primary disease or a secondary malignancy. Cytopenias are treated with supportive care, hematopoietic cytokines, and, occasionally, hematopoietic stem cell support. LD chemotherapy profoundly affects B, T, and natural killer cells. CD19 and B-cell maturation antigen are expressed on normal B cells and plasma cells, respectively, and the targeting of these structures by CAR T-cell products can result in prolonged lymphopenias and hypogammaglobulinemia, making infection an ongoing risk. Late infections are predominantly due to respiratory viruses, reactivation of herpes viruses, and Pneumocystis jirovecii. Patients may require ongoing prophylaxis and immunoglobulin replacement therapy. Although responses may be blunted, vaccinations are generally recommended for most adult CAR T-cell patients. Both hematologic and solid secondary malignancies are a known risk of CAR T-cell therapy; retroviruses used to produce CAR T-cell products have resulted in T-cell cancers secondary to insertional oncogenesis. It is essential to monitor for late complications in adult patients receiving CAR T-cells by using a multidisciplinary approach between referring hematologist oncologists and cell therapy centers to improve the outcomes and quality of life for these patients.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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

BACKGROUND

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

SUMMARY

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

KEY MESSAGES

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

Timeline and outcomes of viral and fungal infections after chimeric antigen receptor T-cell therapy: a large database analysis

OBJECTIVES

This large database analysis aims to describe the incidence, timeline, and risk factors for viral and fungal infections after chimeric antigen receptor (CAR) T-cell therapy.

METHODS

We queried a global research network database, TriNetX, for patients who received CAR T-cell therapy, who were identified and followed for the development of viral and fungal infections. Baseline demographic, oncologic history, laboratory data and medication histories were collected. We evaluated risk factors for respiratory viral infections (RVIs), herpesvirus, fungal infections and mortality using Cox regression.

RESULTS

A total of 2256 patients who received CAR T-cell therapy were included, 1867 (82.7%) were CD19-targeted and 400 (17.7%) were B-cell maturation antigen-targeted. After CAR T-cell infusion, RVIs were the most prevalent (23.3%) with a median onset of 160 days (interquartile range [IQR]: 52-348 days), whereas herpesvirus and fungal infections were less frequent, occurring in 13.6% and 11.4% of cases with median onsets of 71 (IQR, 18-252) and 73 days (IQR, 14-236 days), respectively. On multivariable Cox regression, independent predictors of RVI included acute lymphoblastic leukaemia (hazard ratio [HR], 1.61), prior haematopoietic cell transplant (HCT; HR, 1.29), cytokine release syndrome (HR, 1.41), hemophagocytic lymphohistiocytosis (HR, 1.96) and glucocorticoids (HR, 3.37). Prior HCT (HR, 2.00), hypogammaglobulinemia (HR, 1.51), immune effector cell-associated neurotoxicity syndrome (HR, 1.52) and hemophagocytic lymphohistiocytosis (HR, 1.99) were associated with a higher risk of herpesviruses. Independent predictors of fungal infections included prior HCT (HR, 1.59), cytokine release syndrome (HR, 1.58) and hypogammaglobulinemia (HR, 1.40). Idecabtagene vicleucel was associated with a lower risk of herpesvirus and fungal infections (HR, 0.39 and 0.44, respectively).

DISCUSSION

In a large cohort of CAR T-cell therapy recipients, RVIs were the most common but occurred later, whereas herpesvirus and fungal infections were less frequent but occurred earlier. Prospective studies investigating prophylaxis and pre-emptive monitoring strategies are needed in this population.

Five-Year Follow-Up of Standard-of-Care Axicabtagene Ciloleucel for Large B-Cell Lymphoma: Results From the US Lymphoma CAR T Consortium

PURPOSE

Axicabtagene ciloleucel (axi-cel) is an autologous CD19 chimeric antigen receptor (CAR) T-cell therapy that is approved for the treatment of relapsed or refractory large B-cell lymphoma. Little is known about the long-term survivorship after CAR T-cell therapy.

METHODS

We previously reported the results of 298 patients who were leukapheresed with the intent to receive standard-of-care axi-cel (n = 275 infused) after two or more previous lines of therapy at a median follow-up of 12.9 months. Here, we report extended follow-up of this cohort to a median of 58 months, with a focus on late survivorship events.

RESULTS

Among axi-cel-infused patients, progression-free survival at 5 years was 29% and overall survival (OS) at 5 years was 40%. The 5-year lymphoma-specific survival was 53% with infrequent late relapses. However, the 5-year nonrelapse mortality (NRM) was 16.2%, with over half of NRM events occurring beyond 2 years. Patients who were 60 years and older had a lower risk of relapse (P = .02), but a higher risk of NRM compared with patients younger than 60 years (NRM odds ratio, 4.5 [95% CI, 2.1 to 10.8]; P < .001). Late NRM was mainly due to infections and subsequent malignant neoplasms (SMNs). In total, SMNs occurred in 24 patients (9%), including therapy-related myeloid neoplasms (n = 15), solid tumors (n = 7), and unrelated lymphoid malignancies (n = 2).

CONCLUSION

In the standard-of-care setting, axi-cel exhibits outcomes consistent with those reported in clinical trials, with sustained, durable responses observed at the 5-year time point. However, late infections and the development of SMN are key survivorship issues that reduce long-term survival after CAR T-cell therapy, particularly in the elderly.

Outcome of Pneumocystis Jirovecii pneumonia (PcP) in post-CAR-T patients with hematological malignancies

BACKGROUND

Pneumocystis jirovecii pneumonia (PcP) is an opportunistic infection associated with immunocompromised patients. The development of novel immunotherapies has promoted the incidence of PcP. This study describes the clinical course and outcome of PcP in chimeric antigen receptor (CAR) T cell recipients with hematological malignancies.

METHODS

This is a retrospective case series of CAR-T recipients diagnosed with PcP in our center. The cases were all confirmed by metagenomic next-generation sequencing of clinical samples. The demographic, clinical, and outcome data were retrieved from the patients' medical charts and electronic medical record system.

RESULTS

In total, 8 cases of PcP were identified. The underlying malignancies included T-acute lymphoblastic leukemia (ALL) (n = 1), diffuse large B cell lymphoma (DLBCL) (n = 4), and B-ALL (n = 3). One patient received short-term sulfamethoxazole-trimethoprim (SMZ-TMP) while the others had no prophylaxis. Four patients had neutropenia/lymphopenia at the diagnosis of PcP, and two patients had immunosuppressants within one month before PcP manifestation. The median time from CAR-T infusion to PcP diagnosis was 98.5 days (range 52-251). Seven patients recovered from PcP after proper management while one died of septic shock.

CONCLUSION

PcP can occur after different CAR-T product, and the long-term depletion of immune cells seems to be related to PcP. SMZ-TMP is effective in this setting. More real-world experience of CAR-T therapy is required to assess the incidence and outcome of PcP in this population.

A lesson from fatal invasive fungal infections after CAR-T cell therapy: a case report and literature review

CD19 chimeric antigen receptor T (CAR-T) cell therapy represents an effective approach to treating patients with relapsed or refractory B-cell hematologic malignancies. Nevertheless, owing to the immunosuppressive effects of this regimen, patients undergoing CD19 CAR-T cell therapy may face an elevated risk of invasive fungal infections, which involve fungi penetrating the host's tissues or bloodstream, leading to life-threating infectious diseases. Herein, we present the case of a 17-year-old male diagnosed with acute lymphoblastic leukemia, who subsequently experienced a fatal invasive fungal infection following administration of CAR-T cell therapy. Furthermore, we delve into the identification of risk factors, implementation of preventive measures and exploration of therapeutic interventions for invasive fungal infections after CAR-T cell therapy.

Subsequent Malignancies After CD19-Targeted Chimeric Antigen Receptor T Cells in Patients With Lymphoma

Chimeric antigen receptor (CAR) T cells are an established treatment for B cell non-Hodgkin lymphomas (B-NHL). With the remarkable success in improving survival, understanding the late effects of CAR T cell therapy is becoming more relevant. The aim of this study is to determine the incidence of subsequent malignancies in adult patients with B-NHL. We retrospectively studied 355 patients from 2 different medical centers treated with four different CAR T cell products from 2016 to 2022. The overall cumulative incidence for subsequent malignancies at 36 months was 14% (95% CI: 9.2%, 19%). Subsequent malignancies were grouped into 3 primary categories: solid tumor, hematologic malignancy, and dermatologic malignancy with cumulative incidences at 36 months of 6.1% (95% CI: 3.1%-10%), 4.5% (95% CI: 2.1%-8.1%) and 4.2% (95% CI: 2.1%-7.5%) respectively. Notably, no cases of T cell malignancies were observed. In univariable analysis, increasing age was associated with higher risk for subsequent malignancy. While the overall benefits of CAR T products continue to outweigh their potential risks, more studies and longer follow ups are needed to further demonstrate the risks, patterns, and molecular pathways that lead to the development of subsequent malignancies.

The winding road: Infectious disease considerations for CAR-T and other novel adoptive cellular therapies in the era of COVID-19

Adoptive cellular therapies (ACT) are novel, promising treatments for life-threatening malignancies. In addition to the better known chimeric antigen receptor (CAR) T cells, ACTs include tumor infiltrating lymphocytes (TIL), cancer antigen-specific T cell receptors (TCRs), and CAR-NK (natural killer) cells. In key historic milestones, several adoptive therapies recently received FDA approvals, including 6 CAR-T products for the treatment of hematologic malignancies and the first TIL therapy for the treatment for metastatic melanoma. The rapid pace of clinical trials in the field and the discoveries they provide are ushering in a new era of cancer immunotherapy. However, the potential complications of these therapies are still not fully understood. In particular, patients receiving ACT may be at increased risk for severe infections due to immunocompromise resulting from their underlying malignancies, which are further compounded by the immune derangements that develop in the setting of cellular immunotherapy and/or the preconditioning treatment needed to enhance ACT efficacy. Moreover, these treatments are being readily implemented at a time following the height of the COVID-19 pandemic, and it remains unclear what additional risks these patients may face from SARS-CoV-2 and similar infections. Here, we examine the evidence for infectious complications with emerging adoptive therapies, and provide a focused review of the epidemiology, complications, and clinical management for COVID-19 in CAR-T recipients to understand the risk this disease may pose to recipients of other forms of ACT.

Best Practice Considerations by The American Society of Transplant and Cellular Therapy: Infection Prevention and Management After Chimeric Antigen Receptor T Cell Therapy for Hematological Malignancies

Chimeric antigen receptor (CAR) T-cell therapy is rapidly advancing, offering promising treatments for patients with hematological malignancy. However, associated infectious complications remain a significant concern because of their contribution to patient morbidity and non-relapse mortality. Recent epidemiological insights shed light on risk factors for infections after CAR T-cell therapy. However, the available evidence is predominantly retrospective, highlighting a need for further prospective studies. Institutions are challenged with managing infections after CAR T-cell therapy but variations in the approaches taken underscore the importance of standardizing infection prevention and management protocols across different healthcare settings. Therefore, the Infectious Diseases Special Interest Group of the American Society of Transplantation and Cellular Therapy assembled an expert panel to develop best practice considerations. The aim was to guide healthcare professionals in optimizing infection prevention and management for CAR T-cell therapy recipients and advocates for early consultation of Infectious Diseases during treatment planning phases given the complexities involved. By synthesizing current evidence and expert opinion these best practice considerations provide the basis for understanding infection risk after CAR T-cell therapies and propose risk-mitigating strategies in children, adolescents, and adults. Continued research and collaboration will be essential to refining and effectively implementing these recommendations.

A Primer on Chimeric Antigen Receptor T-cell Therapy-related Toxicities for the Intensivist

Chimeric antigen receptor (CAR) T-cell therapy is an innovative treatment approach that has shown remarkable efficacy against several hematologic malignancies. However, its use can be associated with unique and sometimes severe toxicities that require admission to intensive care unit in 30% of patients, and intensivists should be aware of immune-mediated toxicities of CAR T-cell therapy and management of adverse events. We will review available literature on current diagnostic criteria and therapeutic strategies for mitigating these most common toxicities associated with CAR T-cell therapy including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in the post-infusion period. The authors will also review other toxicities associated with CAR T-cell therapy including cytopenias, acquired immunocompromised states, and infections, and discuss the available literature on best supportive care and prophylaxis recommendations. Critical care medicine specialists play a crucial role in the management of patients undergoing CAR T-cell therapies. With the expanding use of these products in increasing numbers of treating centers, intensivists' roles as part of the multidisciplinary team caring for these patients will have an outsized impact on the continued success of these promising therapies.

Simultaneous targeting of B-cell malignancies and human immunodeficiency virus with bispecific chimeric antigen receptor T cells

Not available.

CD19 CAR T cells for B cell malignancies: a systematic review and meta-analysis focused on clinical impacts of CAR structural domains, manufacturing conditions, cellular product, doses, patient's age, and tumor types

CD19-targeted chimeric antigen receptors (CAR) T cells are one of the most remarkable cellular therapies for managing B cell malignancies. However, long-term disease-free survival is still a challenge to overcome. Here, we evaluated the influence of different hinge, transmembrane (TM), and costimulatory CAR domains, as well as manufacturing conditions, cellular product type, doses, patient's age, and tumor types on the clinical outcomes of patients with B cell cancers treated with CD19 CAR T cells. The primary outcome was defined as the best complete response (BCR), and the secondary outcomes were the best objective response (BOR) and 12-month overall survival (OS). The covariates considered were the type of hinge, TM, and costimulatory domains in the CAR, CAR T cell manufacturing conditions, cell population transduced with the CAR, the number of CAR T cell infusions, amount of CAR T cells injected/Kg, CD19 CAR type (name), tumor type, and age. Fifty-six studies (3493 patients) were included in the systematic review and 46 (3421 patients) in the meta-analysis. The overall BCR rate was 56%, with 60% OS and 75% BOR. Younger patients displayed remarkably higher BCR prevalence without differences in OS. The presence of CD28 in the CAR's hinge, TM, and costimulatory domains improved all outcomes evaluated. Doses from one to 4.9 million cells/kg resulted in better clinical outcomes. Our data also suggest that regardless of whether patients have had high objective responses, they might have survival benefits from CD19 CAR T therapy. This meta-analysis is a critical hypothesis-generating instrument, capturing effects in the CD19 CAR T cells literature lacking randomized clinical trials and large observational studies.

Human herpesvirus 6 reactivation and disease are infrequent in chimeric antigen receptor T-cell therapy recipients

ABSTRACT

Human herpesvirus 6B (HHV-6B) reactivation and disease are increasingly reported after chimeric antigen receptor (CAR) T-cell therapy (CARTx). HHV-6 reactivation in the CAR T-cell product was recently reported, raising questions about product and patient management. Because of overlapping manifestations with immune effector cell-associated neurotoxicity syndrome, diagnosing HHV-6B encephalitis is challenging. We provide 2 lines of evidence assessing the incidence and outcomes of HHV-6B after CARTx. First, in a prospective study with weekly HHV-6B testing for up to 12 weeks after infusion, HHV-6B reactivation occurred in 8 of 89 participants; 3 had chromosomally integrated HHV-6 and were excluded, resulting in a cumulative incidence of HHV-6B reactivation of 6% (95% confidence interval [CI], 2.2-12.5). HHV-6B detection was low level (median peak, 435 copies per mL; interquartile range, 164-979) and did not require therapy. Second, we retrospectively analyzed HHV-6B detection in the blood and/or cerebrospinal fluid (CSF) within 12 weeks after infusion in CARTx recipients. Of 626 patients, 24 had symptom-driven plasma testing, with detection in 1. Among 34 patients with CSF HHV-6 testing, 1 patient had possible HHV-6 encephalitis for a cumulative incidence of 0.17% (95% CI, 0.02-0.94), although symptoms improved without treatment. Our data demonstrate that HHV-6B reactivation and disease are infrequent after CARTx. Routine HHV-6 monitoring is not warranted.

Patients with aggressive B-cell lymphoma receiving CAR T-cell therapy have a low rate of severe infections despite lack of universal antibacterial and antifungal prophylaxis

OBJECTIVES

Our aim was to describe the frequency and severity of infectious complications after chimeric antigen receptor (CAR) T-cell therapy in patients with large B-cell lymphoma (LBCL).

METHODS

We retrospectively reviewed clinical records of LBCL patients treated with CD19-targeted CAR T-cell therapy from July/2018 to December/2021 at our institution, and identified all infectious episodes from CAR T-cell infusion until disease progression, death or last follow-up.

RESULTS

Overall, 137 patients were included. Thirty six percent had received ≥3 previous lines of therapy and 26% an autologous hematopoietic cell transplantation (auto-HCT). Cytokine release syndrome occurred in 87 (64%) patients. Antibacterial prophylaxis was not used in any patient; only 38% received antifungal prophylaxis. Sixty three infectious events were observed in 41 (30%) patients. Fifty two (83%) of the infectious events had at least one pathogen identified (bacteria [n = 38], virus [n = 11], and fungi [n = 3]). Most of the infectious events occurred during hospitalization for CAR-T treatment. Infection-related mortality was observed in two patients. Independent risk factors for infection included male gender, previous auto-HCT, ≥3 lines of treatment and pre-lymphodepletion neutropenia.

CONCLUSIONS

Infections after CAR T-cell therapy in patients with lymphoma are frequent but generally not severe. A conservative and tailored antimicrobial prophylaxis seems to be a safe approach.

CD22-directed CAR T-cell therapy for large B-cell lymphomas progressing after CD19-directed CAR T-cell therapy: a dose-finding phase 1 study

BACKGROUND

Outcomes are poor for patients with large B-cell lymphoma who relapse after CD19-directed chimeric antigen receptor (CAR) T-cell therapy (CAR19). CD22 is a nearly universally expressed B-cell surface antigen and the efficacy of a CD22-directed CAR T-cell therapy (CAR22) in large B-cell lymphoma is unknown, which was what we aimed to examine in this study.

METHODS

In this single centre, open-label, dose-escalation phase 1 trial, we intravenously administered CAR22 at two dose levels (1 million and 3 million CAR22-positive T cells per kg of bodyweight) to adult patients (aged ≥18 years) who relapsed after CAR19 or had CD19-negative large B-cell lymphoma. The primary endpoints were manufacturing feasibility, safety measured by the incidence and severity of adverse events and dose-limiting toxicities, and identification of the maximum tolerated dose (ie, the recommended phase 2 dose). This study is registered with ClinicalTrials.gov (NCT04088890) and is active, but closed for enrolment.

FINDINGS

From Oct 17, 2019, to Oct 19, 2022, a total of 41 patients were assessed for eligibility; however, one patient withdrew. 40 patients underwent leukapheresis and 38 (95%) had CAR T-cell products manufactured successfully. The median age was 65 years (range 25-84), 17 (45%) were women, 32 (84%) had elevated pretreatment lactate dehydrogenase, 11 (29%) had refractory disease to all previous therapies, and patients had received a median of four lines of previous therapy (range 3-8). Of the 38 patients treated, 37 (97%) had relapsed after previous CAR19. The identified maximum tolerated dose was 1 million CAR T cells per kg. Of 29 patients who received the maximum tolerated dose, no patients developed a dose-limiting toxicity or grade 3 or higher cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, or immune effector cell-associated haemophagocytic lymphohistiocytosis-like syndrome.

INTERPRETATION

This trial identifies CD22 as an immunotherapeutic target in large B-cell lymphoma and demonstrates the durable clinical activity of CAR22 in patients with disease progression after CAR19 therapy. Although these findings are promising, it is essential to recognise that this is a phase 1 dose-finding study. Further investigations are warranted to establish the long-term efficacy and to delineate the patient subgroups that will derive the most benefit from this therapeutic approach.

FUNDING

National Cancer Institute, National Institutes of Health, Stanford Cancer Institute, Leukemia & Lymphoma Society, Parker Institute for Cancer Immunotherapy, Lymph & Co, and the European Hematology Association.

Incidence and outcomes of cytomegalovirus reactivation after chimeric antigen receptor T-cell therapy

ABSTRACT

Cytomegalovirus (CMV) reactivation is a major complication among seropositive allogeneic hematopoietic cell transplantation recipients; however, data on CMV reactivation after chimeric antigen receptor (CAR) T-cell therapy are limited. We report the incidence and outcomes of 95 adult CMV-seropositive patients who received CAR T-cell therapy between February 2018 and February 2023. CMV outcomes were CMV reactivation (any viremia) and clinically significant CMV infection (cs-CMV). Thirty-one patients (33%) had evidence of CMV reactivation (any viremia), and 10 patients (11%) had cs-CMV. The median time from CAR T-cell infusion to CMV reactivation was 19 days (interquartile range [IQR], 9-31). The cumulative incidence of CMV (any viremia) was significantly higher among patients with grade 3 to 4 cytokine release syndrome (67 vs 28%; P = .01), and those who received corticosteroids (39 vs 21%; P = .03), anakinra (56 vs 28%; P = .02), or ≥2 immunosuppressants (41 vs 21%; P = .02). Receipt of corticosteroids (18 vs 0%; P = .004), tocilizumab (14 vs 0%; P = .04), anakinra (33 vs 7%; P = .008), and ≥2 immunosuppressants (20 vs 0%; P = .001) were all associated with cs-CMV. Receiving ≥2 immunosuppressants was associated with a twofold increase in CMV reactivation in multivariate analyses (adjusted odds ratio [aOR], 2.27; 95% confidence interval, 1.1-4.8; P = .03). Overall, the 1-year mortality was significantly higher in those with CMV reactivation (57% vs 23%; P = .001). Immunosuppression, particularly with corticosteroids, for the management of CAR T-cell toxicities, is a major risk factor for CMV reactivation.

Overview of infectious complications among CAR T- cell therapy recipients

Chimeric antigen receptor-modified T cell (CAR T-cell) therapy has revolutionized the management of hematological malignancies. In addition to impressive malignancy-related outcomes, CAR T-cell therapy has significant toxicity-related adverse events, including cytokine release syndrome (CRS), immune effector cell associated neurotoxicity syndrome (ICANS), immune effector cell-associated hematotoxicity (ICAHT), and opportunistic infections. Different CAR T-cell targets have different epidemiology and risk factors for infection, and these targets result in different long-term immunodeficiency states due to their distinct on-target and off- tumor effects. These effects are exacerbated by the use of multimodal immunosuppression in the management of CRS and ICANS. The most effective course of action for managing infectious complications involves determining screening, prophylactic, and monitoring strategies and understanding the role of immunoglobulin replacement and re-vaccination strategies. This involves considering the nature of prior immunomodulating therapies, underlying malignancy, the CAR T-cell target, and the development and management of related adverse events. In conclusion, we now have an increasing understanding of infection management for CAR T-cell recipients. As additional effector cells and CAR T-cell targets become available, infection management strategies will continue to evolve.

Rapid identification of early infections in febrile patients after CD19 target CAR-T cell therapy for B-cell malignancies

BACKGROUND

CD19-targeted chimeric antigen receptor T (CAR-T) cell therapy stands out as a revolutionary intervention, exhibiting remarkable remission rates in patients with refractory/relapsed (R/R) B-cell malignancies. However, the potential side effects of therapy, particularly cytokine release syndrome (CRS) and infections, pose significant challenges due to their overlapping clinical features. Promptly distinguishing between CRS and infection post CD19 target CAR-T cell infusion (CTI) remains a clinical dilemma. Our study aimed to analyze the incidence of infections and identify key indicators for early infection detection in febrile patients within 30 days post-CTI for B-cell malignancies.

METHODS

In this retrospective cohort study, a cohort of 104 consecutive patients with R/R B-cell malignancies who underwent CAR-T therapy was reviewed. Clinical data including age, gender, CRS, ICANS, treatment history, infection incidence, and treatment responses were collected. Serum biomarkers procalcitonin (PCT), interleukin-6 (IL-6), and C-reactive protein (CRP) levels were analyzed using chemiluminescent assays. Statistical analyses employed Pearson's Chi-square test, t-test, Mann-Whitney U-test, Kaplan-Meier survival analysis, Cox proportional hazards regression model, Spearman rank correlation, and receiver operating characteristic (ROC) curve analysis to evaluate diagnostic accuracy and develop predictive models through multivariate logistic regression.

RESULTS

In this study, 38 patients (36.5%) experienced infections (30 bacterial, 5 fungal, and 3 viral) within the first 30 days of CAR T-cell infusion. In general, bacterial, fungal, and viral infections were detected at a median of 7, 8, and 9 days, respectively, after CAR T-cell infusion. Prior allogeneic hematopoietic cell transplantation (HCT) was an independent risk factor for infection (Hazard Ratio [HR]: 4.432 [1.262-15.565], P = 0.020). Furthermore, CRS was an independent risk factor for both infection ((HR: 2.903 [1.577-5.345], P < 0.001) and severe infection (9.040 [2.256-36.232], P < 0.001). Serum PCT, IL-6, and CRP were valuable in early infection prediction post-CAR-T therapy, particularly PCT with the highest area under the ROC curve (AUC) of 0.897. A diagnostic model incorporating PCT and CRP demonstrated an AUC of 0.903 with sensitivity and specificity above 83%. For severe infections, a model including CRS severity and PCT showed an exceptional AUC of 0.991 with perfect sensitivity and high specificity. Based on the aforementioned analysis, we proposed a workflow for the rapid identification of early infection during CAR-T cell therapy.

CONCLUSIONS

CRS and prior allogeneic HCT are independent infection risk factors post-CTI in febrile B-cell malignancy patients. Our identification of novel models using PCT and CRP for predicting infection, and PCT and CRS for predicting severe infection, offers potential to guide therapeutic decisions and enhance the efficacy of CAR-T cell therapy in the future.

Bendamustine is a safe and effective lymphodepletion agent for axicabtagene ciloleucel in patients with refractory or relapsed large B-cell lymphoma

BACKGROUND

Fludarabine in combination with cyclophosphamide (FC) is the standard lymphodepletion regimen for CAR T-cell therapy (CAR T). A national fludarabine shortage in 2022 necessitated the exploration of alternative regimens with many centers employing single-agent bendamustine as lymphodepletion despite a lack of clinical safety and efficacy data. To fill this gap in the literature, we evaluated the safety, efficacy, and expansion kinetics of bendamustine as lymphodepletion prior to axicabtagene ciloleucel (axi-cel) therapy.

METHODS

84 consecutive patients with relapsed or refractory large B-cell lymphoma treated with axi-cel and managed with a uniform toxicity management plan at Stanford University were studied. 27 patients received alternative lymphodepletion with bendamustine while 57 received FC.

RESULTS

Best complete response rates were similar (73.7% for FC and 74% for bendamustine, p=0.28) and there was no significant difference in 12-month progression-free survival or overall survival estimates (p=0.17 and p=0.62, respectively). The frequency of high-grade cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome was similar in both the cohorts. Bendamustine cohort experienced lower proportions of hematological toxicities and antibiotic use for neutropenic fever. Immune reconstitution, as measured by quantitative assessment of cellular immunity, was better in bendamustine cohort as compared with FC cohort. CAR T expansion as measured by peak expansion and area under the curve for expansion was comparable between cohorts.

CONCLUSIONS

Bendamustine is a safe and effective alternative lymphodepletion conditioning for axi-cel with lower early hematological toxicity and favorable immune reconstitution.

A meta-analysis to assess the risk of bleeding and thrombosis following chimeric antigen receptor T-cell therapy: Communication from the ISTH SSC Subcommittee on Hemostasis and Malignancy

BACKGROUND

Chimeric antigen receptor T-cell (CAR T-cell) therapy is increasingly utilized for treatment of hematologic malignancies. Hematologic toxicities including thrombosis and bleeding complications have been reported. Accurate estimates for thrombotic and bleeding outcomes are lacking.

OBJECTIVES

We performed a systematic review and meta-analysis in patients who received CAR T-cell therapy for an underlying hematologic malignancy with the objective to: a) assess the thrombosis and bleeding risk associated with CAR T-cell therapy, b) assess the impact of CRS and ICANS on the risks of thrombosis and bleeding, and c) assess the safety of anticoagulant or antiplatelet use in the period following treatment with CAR T-cell therapy.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL up to February 2022 for studies reporting thrombotic or bleeding outcomes in patients receiving CAR T-cell therapy. Pooled event rates were calculated using a random-effects model. We performed subgroup analyses stratified by follow-up duration, CAR T-cell target antigen, and underlying hematologic malignancy.

RESULTS

We included 47 studies with a total of 7040 patients. High heterogeneity between studies precluded reporting of overall pooled rates of thrombotic and bleeding events. In studies with follow-up duration of ≤6 months, the pooled incidence of venous thrombotic events was 2.4% (95% CI, 1.4%-3.4%; I2 = 0%) per patient-month, whereas the rate was 0.1% (95% CI, 0%-0.1%; I2 = 0%) per patient-month for studies with longer follow-up periods (>6 months). The pooled incidences of any bleeding events per patient-month in studies with follow-up duration of ≤6 months and >6 months were 1.9% (95% CI, 0.6%-3.1%; I2 = 78%) and 0.3% (95% CI: 0%-0.8%, I2 = 40%), respectively. Secondary analyses by CAR T-cell target antigen, underlying malignancy, and primary outcome of the studies did not reveal significant differences in the rates of thromboembolism, any bleeding events, or major bleeding events.

CONCLUSION

The risk of both thrombosis and bleeding following CAR T-cell therapy appears to be highest in the initial months following infusion.

CAR19 monitoring by peripheral blood immunophenotyping reveals histology-specific expansion and toxicity

ABSTRACT

Chimeric antigen receptor (CAR) T cells directed against CD19 (CAR19) are a revolutionary treatment for B-cell lymphomas (BCLs). CAR19 cell expansion is necessary for CAR19 function but is also associated with toxicity. To define the impact of CAR19 expansion on patient outcomes, we prospectively followed a cohort of 236 patients treated with CAR19 (brexucabtagene autoleucel or axicabtagene ciloleucel) for mantle cell lymphoma (MCL), follicular lymphoma, and large BCL (LBCL) over the course of 5 years and obtained CAR19 expansion data using peripheral blood immunophenotyping for 188 of these patients. CAR19 expansion was higher in patients with MCL than other lymphoma histologic subtypes. Notably, patients with MCL had increased toxicity and required fourfold higher cumulative steroid doses than patients with LBCL. CAR19 expansion was associated with the development of cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, and the requirement for granulocyte colony-stimulating factor 14 days after infusion. Younger patients and those with elevated lactate dehydrogenase (LDH) had significantly higher CAR19 expansion. In general, no association between CAR19 expansion and LBCL treatment response was observed. However, when controlling for tumor burden, we found that lower CAR19 expansion in conjunction with low LDH was associated with improved outcomes in LBCL. In sum, this study finds CAR19 expansion principally associates with CAR-related toxicity. Additionally, CAR19 expansion as measured by peripheral blood immunophenotyping may be dispensable to favorable outcomes in LBCL.

Risk of Second Tumors and T-Cell Lymphoma after CAR T-Cell Therapy

BACKGROUND

The risk of second tumors after chimeric antigen receptor (CAR) T-cell therapy, especially the risk of T-cell neoplasms related to viral vector integration, is an emerging concern.

METHODS

We reviewed our clinical experience with adoptive cellular CAR T-cell therapy at our institution since 2016 and ascertained the occurrence of second tumors. In one case of secondary T-cell lymphoma, a broad array of molecular, genetic, and cellular techniques were used to interrogate the tumor, the CAR T cells, and the normal hematopoietic cells in the patient.

RESULTS

A total of 724 patients who had received T-cell therapies at our center were included in the study. A lethal T-cell lymphoma was identified in a patient who had received axicabtagene ciloleucel therapy for diffuse large B-cell lymphoma, and both lymphomas were deeply profiled. Each lymphoma had molecularly distinct immunophenotypes and genomic profiles, but both were positive for Epstein-Barr virus and were associated with DNMT3A and TET2 mutant clonal hematopoiesis. No evidence of oncogenic retroviral integration was found with the use of multiple techniques.

CONCLUSIONS

Our results highlight the rarity of second tumors and provide a framework for defining clonal relationships and viral vector monitoring. (Funded by the National Cancer Institute and others.).

Late events after anti-CD19 CAR T-cell therapy for relapsed/refractory B-cell non-Hodgkin lymphoma

Background

The short-term complications from chimeric antigen receptor T-cell therapy (CART) are well characterized, but the long-term complications still need to be further investigated. Therefore, herein, we will review the currently available literature published on the late adverse events following CART.

Methods

We reviewed published data available from pivotal trials and real-world experiences with anti-CD19 CART (CART19) for adults with lymphoma. We defined late events as occurring or persisting beyond 1 month after CART infusion. We focused our literature review on the following late-event outcomes post-CART19: cytopenia, immune reconstitution, infections, and subsequent malignancies.

Results

Grade 3-4 cytopenia beyond 30 days occurs in 30%-40% of patients and beyond 90 days in 3%-22% of patients and is usually managed with growth-factor and transfusion support, along with neutropenic prophylaxis. B-cell aplasia and hypogammaglobulinemia are expected on-target off-tumor effects of CART19, 44%-53% of patients have IgG < 400 mg/dL, and approximately 27%-38% of patients receive intravenous immunoglobulin (IVIG) replacement. Infections beyond the initial month from CART19 are not frequent and rarely severe, but they are more prevalent and severe when patients receive subsequent therapies post-CART19 for their underlying disease. Late neurotoxicity and neurocognitive impairment are uncommon, and other causes should be considered. T-cell lymphoma (TCL) after CART is an extremely rare event and not necessarily related to CAR transgene. Myeloid neoplasm is not rare post-CART, but unclear causality given heavily pretreated patient population is already at risk for therapy-related myeloid neoplasm.

Conclusion

CART19 is associated with clinically significant long-term effects such as prolonged cytopenia, hypogammaglobulinemia, and infections that warrant clinical surveillance, but they are mostly manageable with a low risk of non-relapse mortality. The risk of subsequent malignancies post-CART19 seems low, and the relationship with CART19 and/or prior therapies is unclear; but regardless of the possible causality, this should not impact the current benefit-risk ratio of CART19 for relapsed/refractory B-cell non-Hodgkin lymphoma (NHL).

The Burden of Invasive Fungal Disease Following Chimeric Antigen Receptor T-Cell Therapy and Strategies for Prevention

Chimeric antigen receptor (CAR) T-cell therapy is a novel immunotherapy approved for the treatment of hematologic malignancies. This therapy leads to a variety of immunologic deficits that could place patients at risk for invasive fungal disease (IFD). Studies assessing IFD in this setting are limited by inconsistent definitions and heterogeneity in prophylaxis use, although the incidence of IFD after CAR T-cell therapy, particularly for lymphoma and myeloma, appears to be low. This review evaluates the incidence of IFD after CAR T-cell therapy, and discusses optimal approaches to prevention, highlighting areas that require further study as well as future applications of cellular therapy that may impact IFD risk. As the use of CAR T-cell therapy continues to expand for hematologic malignancies, solid tumors, and most recently to include non-oncologic diseases, understanding the risk for IFD in this uniquely immunosuppressed population is imperative to prevent morbidity and mortality.

Growth Factor in the Setting of CAR T-Cell Therapy: To Use or Not to Use

Patients undergoing chimeric antigen receptor (CAR) T-cell therapy may experience side effects including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), neutropenia, and infection. Growth factor has historically been used to treat neutropenia; however, its role in CAR T-cell therapy is not well explained. Existing data on the safety and efficacy of growth factor are conflicting. The purpose of this integrative review was to explore the safety and efficacy of growth factor in adult patients with hematologic malignancies undergoing CAR T-cell therapy. A literature review was conducted using PubMed, Cumulative Index to Nursing & Allied Health (CINAHL), and Scopus databases. A total of 2,635 articles were retrieved. Four studies were included that looked at the use of growth factor in the CAR T-cell setting. Safety outcomes evaluated included CRS, ICANS, neutropenic fever and/or infection, and neutropenia duration. Efficacy outcomes evaluated included CAR T-cell expansion and treatment response. The literature suggests that growth factor may not increase CRS prevalence, but may lead to an increased grade of CRS, namely grade 2. Growth factor administration does not have any association with ICANS toxicity, CAR T-cell expansion, or treatment response. Its use may not necessarily lead to decreased infection rates but may shorten the duration of neutropenia. Practice implications for providers working with this unique patient population include using growth factor early in the course of CAR T-cell therapy as treatment to shorten the duration of neutropenia rather than infection prophylaxis.

Managing Infection Complications in the Setting of Chimeric Antigen Receptor T cell (CAR-T) Therapy

Chimeric antigen receptor T-cell (CAR T-cell) therapy has changed the paradigm of management of non-Hodgkin's lymphoma (NHL) and Multiple Myeloma. Infection complications have emerged as a concern that can arise in the setting of therapy and lead to morbidity and mortality. In this review, we classified infection complications into three categories, pre-infusion phase from the time pre- lymphodepletion (LD) up to day zero, early phase from day of infusion to day 30 post-infusion, and late phase after day 30 onwards. Infections arising in the pre-infusion phase are closely related to previous chemotherapy and bridging therapy. Infections arising in the early phase are more likely related to LD chemo and the expected brief period of grade 3-4 neutropenia. Infections arising in the late phase are particularly worrisome because they are associated with adverse risk features including prolonged neutropenia, dysregulation of humoral and adaptive immunity with lymphopenia, hypogammaglobinemia, and B cell aplasia. Bacterial, respiratory and other viral infections, protozoal and fungal infections can occur during this time . We recommend enhanced supportive care including prompt recognition and treatment of neutropenia with growth factor support, surveillance testing for specific viruses in the appropriate instance, management of hypogammaglobulinemia with repletion as appropriate and extended antimicrobial prophylaxis in those at higher risk (e.g. high dose steroid use and prolonged cytopenia). Finally, we recommend re-immunizing patients post CAR-T based on CDC and transplant guidelines.

Infectious complications in pediatric patients undergoing CD19+CD22+ chimeric antigen receptor T-cell therapy for relapsed/refractory B-lymphoblastic leukemia

Chimeric antigen receptor T-cell (CAR-T) therapy is effective in the treatment of relapsed/refractory acute B-lymphoblastic leukemia (R/R B-ALL); however, patients who receive CAR-T therapy are predisposed to infections, with considerable detrimental effects on long-term survival rates and the quality of life of patients. This study retrospectively analyzed infectious complications in 79 pediatric patients with R/R B-ALL treated with CAR-T cells at our institution. Overall, 53 patients developed 88 infections. Nine patients experienced nine infections during lymphodepletion chemotherapy, 35 experienced 41 infections during the early phase (days 0-+ 30 after infusion), and 29 experienced 38 infections during the late phase (day + 31-+ 90 after infusion). Pathogens were identified in 31 infections, including 23 bacteria, seven viruses, and one fungus. Four patients were admitted to the intensive care unit for infection and one died. In a univariate analysis, there were ten factors associated with infection, including tumor load, lymphodepleting chemotherapy, neutrophil deficiency and lymphocyte reduction, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), etc. In a multivariate analysis, CRS ≥ grade 3 was identified as a risk factor for infection (hazard ratio = 2.41, 95% confidence interval: 1.08-5.36, P = 0.031). Therefore, actively reducing the CRS grade may decrease the risk of infection and improve the long-term quality of life of these patients.

Associations of granulocyte colony-stimulating factor with toxicities and efficacy of chimeric antigen receptor T-cell therapy in relapsed or refractory B-cell acute lymphoblastic leukemia

Few studies have reported the associations of granulocyte colony-stimulating factor (G-CSF) with cytokine release syndrome (CRS), neurotoxic events (NEs) and efficacy after chimeric antigen receptor (CAR) T-cell therapy for relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). We present a retrospective study of 67 patients with R/R B-ALL who received anti-CD19 CAR T-cell therapy, 41 (61.2%) patients received G-CSF (G-CSF group), while 26 (38.8%) did not (non-G-CSF group). Patients had similar duration of grade 3-4 neutropenia between the two groups. The incidences of CRS and NEs were higher in G-CSF group, while no differences in severity were found. Further stratified analysis showed that the incidence and severity of CRS were not associated with G-CSF administration in patients with low bone marrow (BM) tumor burden. None of the patients with low BM tumor burden developed NEs. However, there was a significant increase in the incidence of CRS after G-CSF administration in patients with high BM tumor burden. The duration of CRS in patients who used G-CSF was longer. There were no significant differences in response rates at 1 and 3 months after CAR T-cell infusion, as well as overall survival (OS) between the two groups. In conclusion, our results showed that G-CSF administration was not associated with the incidence or severity of CRS in patients with low BM tumor burden, but the incidence of CRS was higher after G-CSF administration in patients with high BM tumor burden. The duration of CRS was prolonged in G-CSF group. G-CSF administration was not associated with the efficacy of CAR T-cell therapy.

Cytomegalovirus (CMV) Reactivation and CMV-Specific Cell-Mediated Immunity After Chimeric Antigen Receptor T-Cell Therapy

BACKGROUND

The epidemiology of cytomegalovirus (CMV) after chimeric antigen receptor-modified T-cell immunotherapy (CARTx) is poorly understood owing to a lack of routine surveillance.

METHODS

We prospectively enrolled 72 adult CMV-seropositive CD19-, CD20-, or BCMA-targeted CARTx recipients and tested plasma samples for CMV before and weekly up to 12 weeks after CARTx. We assessed CMV-specific cell-mediated immunity (CMV-CMI) before and 2 and 4 weeks after CARTx, using an interferon γ release assay to quantify T-cell responses to IE-1 and pp65. We tested pre-CARTx samples to calculate a risk score for cytopenias and infection (CAR-HEMATOTOX). We used Cox regression to evaluate CMV risk factors and evaluated the predictive performance of CMV-CMI for CMV reactivation in receiver operator characteristic curves.

RESULTS

CMV was detected in 1 patient (1.4%) before and in 18 (25%) after CARTx, for a cumulative incidence of 27% (95% confidence interval, 16.8-38.2). The median CMV viral load (interquartile range) was 127 (interquartile range, 61-276) IU/mL, with no end-organ disease observed; 5 patients received preemptive therapy based on clinical results. CMV-CMI values reached a nadir 2 weeks after infusion and recovered to baseline levels by week 4. In adjusted models, BCMA-CARTx (vs CD19/CD20) and corticosteroid use for >3 days were significantly associated with CMV reactivation, and possible associations were detected for lower week 2 CMV-CMI and more prior antitumor regimens. The cumulative incidence of CMV reactivation almost doubled when stratified by BCMA-CARTx target and use of corticosteroids for >3 days (46% and 49%, respectively).

CONCLUSIONS

CMV testing could be considered between 2 and 6 weeks in high-risk CARTx recipients.

Serial Evaluation of Preimmunization Antibody Titers in Lymphoma Patients Receiving Chimeric Antigen Receptor T Cell Therapy

Antibody titers and the potential need for immunization have not been formally studied in recipients of chimeric antigen receptor T cell therapy (CAR-T). Prior studies have shown that CD19-targeted CAR-T can induce persistent B cell aplasia but preserve plasma cells for humoral response. Aiming to assess the immune repertoire and antibody titer status of CAR-T recipients, we conducted a retrospective study of immune cell recovery and antibody titers to vaccines in anti-CD19 CAR-T recipients at Mayo Clinic, Rochester. In our cohort of 95 CAR-T recipients, almost one-half had low CD4 T and B cell counts prior to CAR-T that remained persistently low post-CAR-T. Prior to CAR-T, the seronegative rate was lowest for tetanus and highest for pneumococcus irrespective of prior transplantation status (within 2 years of CAR-T). At 3 months post-CAR-T, overall seronegativity rates were similar to pre-CAR-T rates for the prior transplantation and no prior transplantation groups. For patients who received IVIG, loss of seropositivity was seen for hepatitis A (1 of 7; 14%). No seroconversion was noted for pneumococcus. For patients who did not receive IVIG, loss of seropositivity was seen for pneumococcus (2 of 5; 40%) and hepatitis A (1 of 4; 25%). CAR-T recipients commonly experience T cell and B cell lymphopenia and might not have adequate antibody titers against vaccine-preventable diseases despite IVIG supplementation. Loss of antibody titers post-CAR-T is possible, highlighting the need for revaccination. Additional studies with long-term follow-up are needed to inform the optimal timing of immunization post-CAR-T.

Approach to febrile neutropenia in patients undergoing treatments for hematologic malignancies

Febrile neutropenia (FN) is common among hematologic malignancy patients, including recipients of hematopoietic cell transplantation (HCT) and cellular therapies such as chimeric antigen receptor (CAR)-T-cell therapy. Prompt empiric antibiotic use has been the mainstay for decades but a "one-size-fits-all" approach is no longer broadly accepted, as treatment-related infectious risk are more understood. Growing antimicrobial resistance is an increasing clinical challenge. Evolving strategies on de-escalation of broad-spectrum antibiotics in FN without identified infection are areas of particular interest.

Early CAR- CD4+ T-lymphocytes recovery following CAR-T cell infusion: A worse outcome in diffuse large B cell lymphoma

CAR- CD4+ T cell lymphopenia is an emerging issue following CAR-T cell therapy. We analyzed the determinants of CD4+ T cell recovery and a possible association with survival in 31 consecutive patients treated with commercial CAR-T for diffuse large B-cell (DLBCL) or mantle cell lymphoma. Circulating immune subpopulations were characterized through multiparametric-flow cytometry. Six-month cumulative incidence of CAR- CD4+ T cell recovery (≥200 cells/μL) was 0.43 (95% confidence interval [CI]: 0.28-0.65). Among possible determinants of CD4+ T cell recovery, we recognized infusion of a 4-1BB product (tisagenlecleucel, TSA) in comparison with a CD28 (axicabtagene/brexucabtagene, AXI/BRX) (hazard ratio [HR] [95% CI]: 5.79 [1.16-24.12] p = 0.016). Higher CD4+ T cell counts resulted with TSA at month-1, -2 and -3. Moderate-to-severe infections were registered with prolonged CD4+ T cell lymphopenia. Early, month-1 CD4+ T cell recovery was associated with a worse outcome in the DLBCL cohort, upheld in a multivariate regression model for overall survival (HR: 4.46 [95% CI: 1.12-17.71], p = 0.03). We conclude that a faster CAR- CD4+ T cell recovery is associated with TSA as compared to AXI/BRX. Month-1 CAR- CD4+ T cell subset recovery could represent a "red flag" for CAR-T cell therapy failure in DLBCL patients.

Clinical features of neurotoxicity after CD19 CAR T-cell therapy in mantle cell lymphoma

ABSTRACT

CD19 chimeric antigen receptor (CAR) T-cell therapy has proven highly effective for treating relapsed/refractory mantle cell lymphoma (MCL). However, immune effector cell-associated neurotoxicity syndrome (ICANS) remains a significant concern. This study aimed to evaluate the clinical, radiological, and laboratory correlatives associated with ICANS development after CD19 CAR T-cell therapy in patients with MCL. All patients (N = 26) who received standard-of-care brexucabtagene autoleucel until July 2022 at our institution were evaluated. Laboratory and radiographic correlatives including brain magnetic resonance imaging (MRI) and electroencephalogram (EEG) were evaluated to determine the clinical impact of ICANS. Seventeen (65%) patients experienced ICANS after treatment, with a median onset on day 6. Ten (38%) patients experienced severe (grade ≥3) ICANS. All patients with ICANS had antecedent cytokine release syndrome (CRS), but no correlation was observed between ICANS severity and CRS grade. Overall, 92% of EEGs revealed interictal changes; no patients experienced frank seizures because of ICANS. In total, 86% of patients with severe ICANS with postinfusion brain MRIs demonstrated acute neuroimaging findings not seen on pretreatment MRI. Severe ICANS was also associated with higher rates of cytopenia, coagulopathy, increased cumulative steroid exposure, and prolonged hospitalization. However, severe ICANS did not affect treatment outcomes of patients with MCL. Severe ICANS is frequently associated with a range of postinfusion brain MRI changes and abnormal EEG findings. Longer hospitalization was observed in patients with severe ICANS, especially those with abnormal acute MRI or EEG findings, but there was no discernible impact on overall treatment response and survival.

Human Herpes Virus-6 (HHV-6) Reactivation after Hematopoietic Cell Transplant and Chimeric Antigen Receptor (CAR)- T Cell Therapy: A Shifting Landscape

HHV-6B reactivation affects approximately half of all allogeneic hematopoietic cell transplant (HCT) recipients. HHV-6B is the most frequent infectious cause of encephalitis following HCT and is associated with pleiotropic manifestations in this setting, including graft-versus-host disease, myelosuppression, pneumonitis, and CMV reactivation, although the causal link is not always clear. When the virus inserts its genome in chromosomes of germ cells, the chromosomally integrated form (ciHHV6) is inherited by offspring. The condition of ciHHV6 is characterized by the persistent detection of HHV-6 DNA, often confounding diagnosis of reactivation and disease-this has also been associated with adverse outcomes. Recent changes in clinical practice in the field of cellular therapies, including a wider use of post-HCT cyclophosphamide, the advent of letermovir for CMV prophylaxis, and the rapid expansion of novel cellular therapies require contemporary epidemiological studies to determine the pathogenic role and spectrum of disease of HHV-6B in the current era. Research into the epidemiology and clinical significance of HHV-6B in chimeric antigen receptor T cell (CAR-T cell) therapy recipients is in its infancy. No controlled trials have determined the optimal treatment for HHV-6B. Treatment is reserved for end-organ disease, and the choice of antiviral agent is influenced by expected toxicities. Virus-specific T cells may provide a novel, less toxic therapeutic modality but is more logistically challenging. Preventive strategies are hindered by the high toxicity of current antivirals. Ongoing study is needed to keep up with the evolving epidemiology and impact of HHV-6 in diverse and expanding immunocompromised patient populations.

Torque Teno Virus DNA Load in Blood as an Immune Status Biomarker in Adult Hematological Patients: The State of the Art and Future Prospects

A solid body of scientific evidence supports the assumption that Torque teno virus (TTV) DNA load in the blood compartment may behave as a biomarker of immunosuppression in solid organ transplant recipients; in this clinical setting, high or increasing TTV DNA levels precede the occurrence of infectious complications, whereas the opposite anticipates the development of acute rejection. The potential clinical value of the TTV DNA load in blood to infer the risk of opportunistic viral infection or immune-related (i.e., graft vs. host disease) clinical events in the hematological patient, if any, remains to be determined. In fact, contradictory data have been published on this matter in the allo-SCT setting. Studies addressing this topic, which we review and discuss herein, are highly heterogeneous as regards design, patient characteristics, time points selected for TTV DNA load monitoring, and PCR assays used for TTV DNA quantification. Moreover, clinical outcomes are often poorly defined. Prospective, ideally multicenter, and sufficiently powered studies with well-defined clinical outcomes are warranted to elucidate whether TTV DNA load monitoring in blood may be of any clinical value in the management of hematological patients.

Bilateral Cytomegalovirus Retinitis After Chimeric Antigen Receptor T-cell Therapy for B-cell Lymphoma

Cytomegalovirus (CMV) retinitis is commonly associated with immunosuppression and can cause irreversible vision loss. Chimeric antigen receptor T-cell (CAR-T) therapy has emerged as an effective cancer treatment option but requires immunosuppression, thereby increasing the possibility of acquiring opportunistic infections such as CMV. We present the case of a 76-year-old female with a history of hypertension and type 2 diabetes mellitus who initially presented with shortness of breath and was diagnosed with the activated B-cell subset of diffuse large B-cell lymphoma (DLBCL). She received multiple cycles of chemotherapy and experienced relapses with cardiac involvement. The patient developed vision loss in the right eye and was diagnosed with bilateral posterior vitritis. She underwent various treatments, including radiotherapy, systemic chemotherapy, cataract extraction, and vitrectomy. After CAR-T therapy, she developed bilateral CMV retinitis, confirmed through polymerase chain reaction testing and managed by valganciclovir. Overall, this case report describes the first reported case of bilateral CMV retinitis following CAR-T therapy for DLBCL. It emphasizes the need for early recognition and treatment of CMV retinitis to prevent permanent vision loss. The report also underscores the importance of regular ocular screening and consideration of prophylactic measures in patients undergoing CAR-T therapy.

A new way of identifying viral pathogens reactivating in cellular therapy products

In this article, we discuss a recently published article that demonstrated a novel way of identifying viral pathogens reactivating in human cells to be used as cellular therapy, in this instance chimeric antigen receptor (CAR) T cells. The authors used search engines and databases to identify viruses able to reactivate in T cells and then tested this initially in T-cell cultures, specifically human herpesvirus 6. This virus was then shown to reactivate infrequently in vitro and in vivo in CAR T cells as a consequence of T-cell activation. The methodology may be most clinically useful for more frequently reactivating viruses in other types of cellular therapy such as allogenic CAR T cells or induced pluripotent stem cells.

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.

Timing of anti-PD-L1 antibody initiation affects efficacy/toxicity of CD19 CAR T-cell therapy for large B-cell lymphoma

ABSTRACT

More than half of the patients treated with CD19-targeted chimeric antigen receptor (CAR) T-cell immunotherapy for large B-cell lymphoma (LBCL) do not achieve durable remission, which may be partly due to PD-1/PD-L1-associated CAR T-cell dysfunction. We report data from a phase 1 clinical trial (NCT02706405), in which adults with LBCL were treated with autologous CD19 CAR T cells (JCAR014) combined with escalating doses of the anti-PD-L1 monoclonal antibody, durvalumab, starting either before or after CAR T-cell infusion. The addition of durvalumab to JCAR014 was safe and not associated with increased autoimmune or immune effector cell-associated toxicities. Patients who started durvalumab before JCAR014 infusion had later onset and shorter duration of cytokine release syndrome and inferior efficacy, which was associated with slower accumulation of CAR T cells and lower concentrations of inflammatory cytokines in the blood. Initiation of durvalumab before JCAR014 infusion resulted in an early increase in soluble PD-L1 (sPD-L1) levels that coincided with the timing of maximal CAR T-cell accumulation in the blood. In vitro, sPD-L1 induced dose-dependent suppression of CAR T-cell effector function, which could contribute to inferior efficacy observed in patients who received durvalumab before JCAR014. Despite the lack of efficacy improvement and similar CAR T-cell kinetics early after infusion, ongoing durvalumab therapy after JCAR014 was associated with re-expansion of CAR T cells in the blood, late regression of CD19+ and CD19- tumors, and enhanced duration of response. Our results indicate that the timing of initiation of PD-L1 blockade is a key variable that affects outcomes after CD19 CAR T-cell immunotherapy for adults with LBCL.

Essentials of CAR-T Therapy and Associated Microbial Challenges in Long Run Immunotherapy

Chimeric antigen receptor (CAR)-T cell therapy has shown potential in improving outcomes for individuals with hematological malignancies. However, achieving long-term full remission for blood cancer remains challenging due to severe life-threatening toxicities such as limited anti-tumor efficacy, antigen escape, trafficking restrictions, and limited tumor invasion. Furthermore, the interactions between CAR-T cells and their host tumor microenvironments have a significant impact on CAR-T function. To overcome these considerable hurdles, fresh methodologies and approaches are needed to produce more powerful CAR-T cells with greater anti-tumor activity and less toxicity. Despite advances in CAR-T research, microbial resistance remains a significant obstacle. In this review, we discuss and describe the basics of CAR-T structures, generations, challenges, and potential risks of infections in CAR-T cell therapy.

High pretreatment disease burden as a risk factor for infectious complications following CD19 chimeric antigen receptor T-cell therapy for large B-cell lymphoma

Infection has emerged as the chief cause of non-relapse mortality (NRM) post CD19-targeting chimeric antigen receptor T-cell therapy (CAR-T) therapy. Even though up to 50% of patients may remain infection-free, many suffer multiple severe, life-threatening, or fatal infectious events. The primary aim of this study was to explore severe and life-threatening infections post licensed CAR-T therapy in large B-cell lymphoma, with a focus on the role of disease burden and disease sites in assessing individual risk. We sought to understand the cohort of patients who experience ≥2 infections and those at the highest risk of infectious NRM. Our analysis identifies a higher disease burden after bridging therapy as associated with infection events. Those developing ≥2 infections emerged as a uniquely high-risk cohort, particularly if the second (or beyond) infection occurred during an episode of immune effector cell-associated neurotoxicity syndrome (ICANS) or while on steroids and/or anakinra for ICANS. Herein, we also describe the first reported cases of "CAR-T cold sepsis," a phenomenon characterized by the lack of an appreciable systemic inflammatory response at the time of detection of infection. We propose a risk-based strategy to encourage heightened clinician awareness of cold sepsis, with a view to reducing NRM.

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.

Infections in haematology patients treated with CAR-T therapies: A systematic review and meta-analysis

A registered (PROSPERO - CRD42022346462) systematic review and meta-analysis was conducted of all-grade infections amongst adult patients receiving CAR-T therapy for haematological malignancy. Meta-analysis of pooled incidence, using random effects model, was conducted. Cochran's Q test examined heterogeneity. 2678 patients across 33 studies were included in the primary outcome. Forty-percent of patients (95% CI: 0.33 - 0.48) experienced an infection of any grade. Twenty-five percent of infection events (95% CI: 0.16 - 0.34) were severe. Late infections were as common as early infections (IRR = 0.86, 95% CI: 0.38 - 1.98). All-grade infections, bacterial and viral infections were highest in myeloma patients at 57%, 37% and 28% respectively. Patients with NHL more commonly experienced late infections. Pooled rate of invasive candidiasis/yeast infections was 2% in studies utilizing anti-yeast prophylaxis. This review identified a high rate of all-grade infections, moderate rate of severe infections, and myeloma as a high-risk haematological group.

Early and Late Toxicities of Chimeric Antigen Receptor T-Cells

As chimeric antigen receptor (CAR) T-cell therapy is increasingly integrated into clinical practice across a range of malignancies, identifying and treating inflammatory toxicities will be vital to success. Early experiences with CD19-targeted CAR T-cell therapy identified cytokine release syndrome and neurotoxicity as key acute toxicities and led to unified initiatives to mitigate the influence of these complications. In this section, we provide an update on the current state of CAR T-cell-related toxicities, with an emphasis on emerging acute toxicities affecting additional organ systems and considerations for delayed toxicities and late effects.