The utilization of chimeric antigen receptor (CAR) T-cell therapy to target cluster of differentiation (CD)19 in cancer immunotherapy has been a recent and significant advancement. Although this approach is highly specific and selective, it is not without complications. Therefore, a systematic review was conducted to assess the current state of positron emission tomography (PET) in evaluating the adverse effects induced by CAR T-cell therapy. A thorough search of relevant articles was performed in databases such as PubMed, Scopus, and Web of Science up until March 2024. Two reviewers independently selected articles and extracted data, which was then organized and categorized using Microsoft Excel. The risk of bias and methodological quality was assessed. In total, 18 articles were examined, involving a total of 753 patients, in this study. A wide range of utilities were analyzed, including predictive, correlative, and diagnostic utilities. While positive outcomes were observed in all the mentioned areas, quantitative analysis of the included studies was hindered by their heterogeneity and use of varying PET-derived parameters. This study offers a pioneering exploration of this promising field, with the goal of encouraging further and more focused research in upcoming clinical trials.

BACKGROUND: Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are common toxicities associated with chimeric antigen receptor (CAR) T-cell therapy. Severe grade 3 or higher ICANS is less common and requires the use of corticosteroids with or without an Interleukin (IL)-6 receptor antagonist. Although corticosteroids are effective in the management of CRS and ICANS, their impact on CAR T efficacy remains unknown.
METHODS: We present the case of a 65-year-old male who received CAR T-cell therapy with brexucabtagene autoleucel for stage I/II Mantle Cell Lymphoma (MCL) and achieved complete remission despite receiving a prolonged course of corticosteroids for severe ICANS.
METHODS: The patient received treatment with high-dose corticosteroids, tocilizumab, and anakinra, in addition to multiple antiepileptic agents. Despite a remitting relapsing pattern of ICANS, the patient not only recovered from the life-threatening complication but also achieved a complete remission at three months post CAR T.
CONCLUSIONS: This case describes the successful use of corticosteroids for the management of ICANS in a patient treated with CAR T-cell therapy for MCL.

Immunotherapy has revolutionized treatment of cancer over the past two decades. The antitumor effects of immunotherapy approaches are at the expense of growing spectrum of immune-related adverse events (irAEs) due to cross-reactivity between the tumor and normal host tissue. These adverse events can happen in any organ and range from mild to severe and even life-threatening conditions. While neurological irAEs associated with immune checkpoint inhibitors (CPIs) are rare, they pose a significant challenge in management as the clinical phenotypes are heterogenous and frequently necessitate cessation of therapy and systemic immune suppression and lead to transient functional decline. On the other hand, immune effector cell-associated neurotoxicity (ICANS) is common, frequently occurs in conjunction with cytokine release syndrome (CRS), and poses a significant clinical challenge to the development and widespread use of these effective therapies. Early recognition of these neurological syndromes, timely diagnosis, and thoughtful management are key for further clinical development of these effective therapies in cancer patients. Here, we describe clinical phenotypes of CPI-induced neurological complications and ICANS and discuss steps in clinical monitoring, diagnosis, and effective management.

In the relapsed/refractory setting for treatment of large B-cell lymphoma (LBCL), chimeric antigen receptor T-cell (CAR-T) therapy has emerged as an effective treatment modality. Patients often have aggressive disease that requires prompt treatment in the form of bridging therapy (BT) for disease stabilisation while CAR-T cells are manufactured. Patients (n = 75) undergoing CAR-T therapy infusion for LBCL at our institution were identified. A total of 52 (69·3%) received BT and 23 (30·7%) received no BT (NBT). BT modalities included systemic BT (SBT) in 28 patients, radiation BT (RBT) in 14, and high-dose steroid BT (HDS) in 10. There was no difference in incidence of cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome between BT and NBT (P = 0·18 and P = 0·53 respectively). Prolonged cytopenias at Day 180 were more common in BT than NBT (50% vs. 13·3%, P = 0·04). The SBT and RBT subgroups had more cytopenias at Day 180 compared to the HDS and NBT subgroups (58·3% and 57·1% vs. 20% and 13·3% respectively, P = 0·04). Disease response at last follow-up, progression-free survival and overall survival were similar between BT, NBT, and BT subgroups. In summary, BT can be safely considered in patients undergoing CAR-T therapy. However, those undergoing BT with SBT or RBT are at higher risk of prolonged cytopenias after CAR-T therapy.

The Cornell Assessment for Pediatric Delirium (CAPD) was first proposed by the Pediatric Acute Lung Injury and Sepsis Investigators Network-Stem Cell Transplantation and Cancer Immunotherapy Subgroup and MD Anderson CARTOX joint working committees, for detection of immune effector cell associated neurotoxicity (ICANS) in pediatric patients receiving chimeric antigen receptor (CAR) T-cell therapy. It was subsequently adopted by the American Society for Transplantation and Cellular Therapy. The utility of CAPD as a screening tool for early diagnosis of ICANS has not been fully characterized. We conducted a retrospective study of pediatric and young adult patients (n=15) receiving standard-of-care CAR T-cell products. Cytokine release syndrome (CRS) and ICANS occurred in 87% and 40% of patients, respectively. ICANS was associated with significantly higher peaks of serum ferritin. A change in CAPD from a prior baseline was noted in 60% of patients with ICANS, 24-72 h prior to diagnosis of ICANS. The median change from baseline to maximum CAPD score of patients who developed ICANS versus those who did not was 13 versus 3, respectively (p=0.0004). Changes in CAPD score from baseline may be the earliest indicator of ICANS among pediatric and young adult patients which may warrant closer monitoring, with more frequent CAPD assessments.

Over the past decade, chimeric antigen receptor (CAR) T-cell therapy has significantly improved the outlook for many patients with relapsed and/or refractory B-cell malignancies. The use of CAR T-cell therapy and other therapeutic immune effector cells will likely continue to expand with the development of other targets and use in solid tumors. Although these therapies have shown significant promise in the treatment of some malignancies, they can be associated with unique toxicities including cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome which can be fatal if not identified early and treated appropriately. An understanding of how best to manage the toxicities associated with CAR T-cell therapy is continually evolving. Institutions providing CAR T-cell therapy have undergone changes in infrastructure and staffing models in order to safely care for patients receiving this novel therapy. As members of a multi-disciplinary health care team, advanced practice providers play significant roles in caring for this patient population and must be well-versed in the recognition, grading, and appropriate management of CAR T-cell therapy-related toxicities as these providers care for patients in multiple settings across the continuum of care.