Adverse Reactions in Relapsed/Refractory B-Cell Lymphoma Administered with Chimeric Antigen Receptor T Cell Alone or in Combination with Autologous Stem Cell Transplantation

(1) Background: The combination of CAR-T with ASCT has been observed to enhance the efficacy of CAR-T cell therapy. However, the impact of this combination on adverse reactions is still uncertain. (2) Methods: Between January 2019 and February 2023, 292 patients diagnosed with r/r B-cell lymphoma received either CAR-T therapy alone or in combination with ASCT at our institution. We evaluated the incidence of CRS and CRES and utilized a logistic regression model to identify factors contributing to severe CRS (grade 3-4) and CRES (grade 3-4). (3) Results: The overall incidence of CRS and CRES was 78.9% and 8.2% in 147 patients receiving CAR-T alone, and 95.9% and 15.2% in 145 patients receiving CAR-T combined with ASCT, respectively. The incidence of overall CRS (p < 0.0001) and mild CRS (grade 1-2) (p = 0.021) was elevated in the ASCT combined with CAR-T group. No significant difference was observed in severe CRS and CRES between the groups. Among the 26 cases of lymphoma involving the central nervous system (CNS), 96.2% (25/26) developed CRS (15.4% grade 3-4), and 34.6% (9/26) manifested CRES (7.7% grade 3-4). Female patients had a lower incidence of severe CRS but a higher incidence of severe CRES. Lymphomas with CNS involvement demonstrated a higher risk of CRES compared to those without central involvement. (4) Conclusions: The combination of ASCT with CAR-T demonstrated a preferable option in r/r B-cell lymphoma without an increased incidence of severe CRS and CRES.

Prevalence and characterization of Carbapenem-Resistant Enterobacterales among inpatients and outpatients in Skikda, Algeria

INTRODUCTION

The spread of Carbapenemase-producing Enterobacterales (CPEs) has become a significant concern in Algeria, with limited data available on their presence in community settings. This research investigated the resistance mechanisms of carbapenem-resistant Enterobacterales (CREs) collected from hospitals and the community in Skikda city, Algeria, between December 2020 and June 2022.

METHODOLOGY

The study collected Enterobacterales strains resistant to ertapenem from inpatient and outpatient populations. An automated system was used for identification and antibiotic susceptibility testing. β-lactamase production was evaluated through phenotypic tests and confirmed by standard PCR. Lastly, the carbapenemase genes were sequenced using the Sanger method.

RESULTS

17 CRE were isolated, with 9 from inpatients and 8 from outpatients. These isolates belonged to four species: Klebsiella pneumoniae (n = 8), Escherichia coli (n = 6), Enterobacter cloacae (n = 1), and Proteus mirabilis (n = 1). Of 15 CPEs, 11 were extended-spectrum β-lactamases (ESBLs) positive, 5 were plasmid-mediated cephalosporinase (AmpC) positive, and 1 harbored all three β-lactamases. All metallo-β-lactamase-producing strains carried the New Delhi metallo-beta-lactamase gene (blaNDM), including 5 NDM-1 and 7 NDM-5 variants. The presence of blaOXA-48 and blaOXA-244 was observed in one outpatient strain each. NDM was associated with Cefotaximase Munich (CTX-M) ESBL in 8 isolates, while Cephamycinase (CMY) was detected in 3 NDM-5-producing E. coli.

CONCLUSIONS

This research highlights the rising prevalence of carbapenemases NDM-1 and NDM-5 among inpatients and outpatients and supports the notion that OXA-48 is becoming increasingly widespread beyond Algerian hospitals.

Host defense functions of the epididymal amyloid matrix

The epididymal lumen is an immunologically distinct environment. It maintains tolerance for the naturally antigenic spermatozoa to allow their maturation into functional cells while simultaneously defending against pathogens that can ascend the male tract and cause infertility. We previously demonstrated that a nonpathological amyloid matrix that includes several cystatin-related epididymal spermatogenic (CRES) subgroup family members is distributed throughout the mouse epididymal lumen but its function was unknown. Here, we reveal a role for the epididymal amyloid matrix in host defense and demonstrate that the CRES amyloids and CD-1 mouse epididymal amyloid matrix exhibit potent antimicrobial activity against bacterial strains that commonly cause epididymal infections in men. We show the CRES and epididymal amyloids use several defense mechanisms including bacterial trapping, disruption of bacterial membranes and promotion of unique bacterial ghost-like structures. Remarkably, these antimicrobial actions varied depending on the bacterial strain indicating CRES amyloids and the epididymal amyloids elicit strain-specific host defense responses. We also demonstrate that the CRES monomer and immature assemblies of the epididymal amyloid transitioned into advanced structures in the presence of bacteria, suggesting their amyloid-forming/shape-shifting properties allows for a rapid reaction to a pathogen and provides an inherent plasticity in their host defense response. Together, our studies reveal new mechanistic insight into how the male reproductive tract defends against pathogens. Future studies using a mouse model for human epididymitis are needed to establish the epididymal amyloid responses to pathogens in vivo. Broadly, our studies provide an example of why nature has maintained the amyloid fold throughout evolution.

Incidence and Management of Effusions Before and After CD19-Directed Chimeric Antigen Receptor (CAR) T Cell Therapy in Large B Cell Lymphoma

In patients with lymphoma, third-space fluid accumulations may develop or worsen during cytokine release syndrome (CRS) associated with chimeric antigen receptor (CAR) T cell therapy. Pre-existing symptomatic pleural effusions were excluded by the ZUMA-1 trial of axicabtagene ciloleucel for large B cell lymphoma (LBCL) and variants. The incidence and management of effusions during CAR T cell therapy for LBCL are unknown. We performed a single-center retrospective study evaluating 148 patients receiving CD19-directed CAR T cell therapy for LBCL between May 2015 and September 2019. We retrospectively identified patients who had radiographic pleural, pericardial, or peritoneal effusions that were present prior to the time of CAR T infusion (pre-CAR T) or that newly developed during the first 30 days after CAR T-cell infusion (post-CAR T). Of 148 patients, 19 patients had a pre-CAR T effusion, 17 patients without pre-existing effusion developed a new infusion after CAR T, and 112 patients had no effusions. Comparing pre-CAR T effusions to new effusions post-CAR T, pre-CAR T effusions were more often malignant (84% versus 12%), persistent beyond 30 days (95% versus 18%), and required interventional drainage after CAR T infusion (79% versus 0%). Compared to patients with no effusion, patients with pre-CAR T therapy effusions had a higher frequency of high-risk baseline characteristics, such as bulky disease and high International Prognostic Index. Similarly, patients with pre-CAR T therapy effusions had a higher rate of toxicity with grade 3 or higher CRS occurring in 32% of patients. On multivariate analysis adjusting for age, Eastern Cooperative Oncology Group status, bulky disease, albumin, and lactate dehydrogenase, a pre-CAR T therapy effusion was associated with reduced overall survival (hazard ratio, 2.34; 95% confidence interval, 1.09 to 5.03; P = .03). Moreover, there was higher non-relapse mortality (11% versus 1%; P = .005). Post-CAR T effusions were not associated with significant difference in survival. Effusions commonly complicate CAR T cell therapy for lymphoma. Malignant effusions that occur prior to CAR T therapy are frequently persistent and require therapeutic intervention, and patients have a higher rate of toxicity and death. Effusions that newly occur after CAR T therapy can generally be managed medically and tend not to persist.

CAR T-Cell Therapy Is Effective but Not Long-Lasting in B-Cell Lymphoma of the Brain

Advanced central nervous system (CNS) lymphoma is an exclusion criterion for most chimeric antigen receptor (CAR) T-cell studies due to the associated levels of neurotoxicity. In this study, we described five patients with chemorefractory B-cell CNS lymphoma who received CAR19 and CAR22 T-cell “Cocktail” therapy and follow-up for 6–16 months. All patients experienced cytokine release syndrome (CRS). Two patients experienced CAR T-cell-related encephalopathy syndrome (CRES), which was controllable. The best response was observed in two patients, who successfully achieved complete remissions (CR), and the other three patients achieved partial remissions (PR). Four patients had progressive disease (PD) after remission. In addition, one CR patient and one PD patient accepted CAR T-cell infusion following hematopoietic stem cell transplantation therapy in the 3rd month and were in ongoing remission for 14 and 6 months of follow-up, respectively. The targeted antigens in two patients were still positive, and CAR T-cells were reboosted in the cerebrospinal fluid (CSF) after PD, but a small number of CD3-positive T-cells were observed to infiltrate into the tumor. Our study indicates the efficacy of CAR T-cell therapy for CNS lymphoma with an acceptable safety profile; however, the remission did not last long, perhaps due to the tumor immunosuppressive microenvironment (TME) of the CNS. CAR T-cell therapy should be combined with other treatments to help improve the TME of cerebral lymphoma.

Interleukin-6-knockdown of chimeric antigen receptor-modified T cells significantly reduces IL-6 release from monocytes

Background

T cells expressing a chimeric antigen receptor (CAR) engineered to target CD19 can treat leukemia effectively but also increase the risk of complications such as cytokine release syndrome (CRS) and CAR T cell related encephalopathy (CRES) driven by interleukin-6 (IL-6). Here, we investigated whether IL-6 knockdown in CART-19 cells can reduce IL-6 secretion from monocytes, which may reduce the risk of adverse events.

Methods

Supernatants from cocultures of regular CART-19 cells and B lymphoma cells were added to monocytes in vitro, and the IL-6 levels in monocyte supernatants were measured 24 h later. IL-6 expression was knocked down in regular CART-19 cells by adding a short hairpin RNA (shRNA) (termed ssCART-19) expression cassette specific for IL-6 to the conventional CAR vector. Transduction efficiency and cell proliferation were measured by flow cytometry, and cytotoxicity was measured by evaluating the release of lactate dehydrogenase into the medium. Gene expression was assessed by qRT-PCR and RNA sequencing. A xenograft leukemia mouse model was established by injecting NOD/SCID/γc-/- mice with luciferase-expressing B lymphoma cells, and then the animals were treated with regular CART-19 cells or ssCART-19. Tumor growth was assessed by bioluminescence imaging.

Results

Both recombinant IL-6 and CART-19 derived IL-6 significantly triggered IL-6 release by monocytes. IL-6 knockdown in ssCART-19 cells dramatically reduced IL-6 release from monocytes in vitro stduy. In vivo study further demonstrated that the mice bearing Raji cells treated with ssCART-19 cells showed significant lower IL-6 levels in serum than those treated with regular CART-19 cells, but comparable anti-tumor efficacy between the animal groups.

Conclusion

CAR T-derived IL-6 is one of the most important initiators to amplify release of IL-6 from monocytes that further drive sCRS development. IL-6 knockdown in ssCART-19 cells by shRNA technology provide a promising strategy to improve the safety of CAR T cell therapy.

Cellular therapy: Immune-related complications

The advent of chimeric antigen receptor T (CAR-T) and the burgeoning field of cellular therapy has revolutionized the treatment of relapsed/refractory leukemia and lymphoma. This personalized "living therapy" is highly effective against a number of malignancies, but this efficacy is tempered by side effects relatively unique to immunotherapies, including CAR-T. The overwhelming release of cytokines and chemokines by activated CAR-T and other secondarily activated immune effector cells can lead to cytokine release syndrome (CRS), which can have clinical and pathophysiology similarities to systemic inflammatory response syndrome and macrophage activating syndrome/hemophagocytic lymphohistiocytosis. Tocilizumab, an anti-IL6 receptor antibody, was recently FDA approved for treatment of CRS after CAR-T based on its ability to mitigate CRS in many patients. Unfortunately, some patients are refractory and additional therapies are needed. Patients treated with CAR-T can also develop neurotoxicity and, as the biology is poorly understood, current therapeutic interventions are limited to supportive care. Nevertheless, a number of recent studies have shed new light on the pathophysiology of CAR-T-related neurotoxicity, which will hopefully lead to effective treatments. In this review we discuss some of the mechanistic contributions intrinsic to the CAR-T construct, the tumor being treated, and the individual patient that impact the development and severity of CRS and neurotoxicity. As CAR-T and cellular therapy have redefined the concept of personalized medicine, so too will personalization be necessary in managing the unique side effects of these therapies.

[Management of CAR-T cell-related encephalopathy syndrome in adult and pediatric patients: Recommendations of the French Society of Bone Marrow transplantation and cellular Therapy (SFGM-TC)]

CAR-T cell-related encephalopathy syndrome (CRES) reflects the potential neurotoxicity of this therapeutic approach and must be considered in the presence of any neurological symptom after the infusion of the CAR-T. This is the second most common adverse event under this therapy and its incidence varies between 12 and 55%. The median time of the onset of the first neurologic symptoms is 4days after CAR-T infusion. The duration of CRES symptoms is generally between 2 and 4days, but late CRES may occur. Monitoring and diagnosis of CERS includes clinical exam, magnetic resonance imaging and electroencephalography. In addition to symptomatic treatments, corticosteroids represent the cornerstone of the high-grade CERS treatment. Drugs targeting IL-6 should be restricted to severe forms, especially those associated with cytokine release syndrome. The purpose of this workshop is to provide practical help in dealing with this complication.