Alotaibi, Shaykhah

T cell fitness has emerged as a critical determinant of the efficacy and persistence of Chimeric Antigen Receptor (CAR)-T cell therapy. Defined by the capacity of T cells to proliferate, resist exhaustion, persist in vivo , and exert sustained effector functions, T cell fitness reflects the integration of a dynamic network of intrinsic and extrinsic regulatory mechanisms. In this review, we present a comprehensive synthesis of the molecular and cellular foundations underlying T cell fitness, emphasizing the influence of differentiation trajectories, signaling pathways, metabolic reprogramming, and epigenetic modifications. We further discuss the impact of patient-specific conditions such as age as well as disease biology, prior therapeutic exposures, and timing and quality of T cell collection, on the phenotypic and functional efficacy of CAR-T cell products. Beyond delineating these determinants, we highlight emerging strategies aimed at enhancing T cell fitness. Importantly, we propose T cell fitness as an integrated, multi-layered systems property emerging from the interaction between differentiation state, signaling architecture, metabolic–mitochondrial competence, epigenetic stability, and host-specific inflammatory and treatment-related pressures. We introduce a mechanistic framework that links these layers across the CAR-T therapeutic timeline from leukapheresis to post-infusion tumor engagement and outline how this framework can be operationalized into measurable parameters to guide patient stratification, manufacturing decisions, and rational therapeutic interventions.

Introduction Chimeric antigen receptor T-cell therapy (CART) has revolutionized the treatment algorithm of relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL). However, approximately only 40% of cases achieve long-term durable remissions. Prognostication remains important as it would allow more precise prediction of outcomes and develop a personalized treatment approach. Currently, it is unclear whether prognostic factors that have been predictive of outcomes in the pre-CART era, remain important in the current era. We conducted a single center observational study to assess the prognostic significance of extra nodal involvement (ENI) on long-term outcomes following CART in B-cell NHL. Methods The primary aim was to evaluate the prognostic significance of ENI on long-term outcomes in patients with B-cell NHL treated with CART. The second aim was to specifically evaluate the impact of gastrointestinal (GI) involvement. Continuous variables were summarized as median (range) and categorical variables were reported as frequency (percentage). Kaplan-Meier method was used to estimate freedom from events at different time points and draw corresponding survival curves. Log-rank test was used to compare freedom from events between histology groups. Results 74 patients were included in this analysis, with a median age of 62 (18-85) years. Fifty-three (72%) had evidence of ENI. Twenty-four (47%) had GI involvement as the sole site of ENI or with other sites of ENI. Forty-three (58%) patients were male and diffuse large B-cell lymphoma (DLBCL) was the most common histology (n=50 [54%]) followed by transformed follicular lymphoma (n=20 [27%]). Most patients had advanced stage disease at time of CART (n=71 [96%]) and 3 (4%) had CNS involvement at any time prior to CART. Median number of prior lines of systemic treatment were 2 (1-7) and 64 (87%) had progressive disease at time of CART. Axicabtagene ciloleucel was the most used CART product (n=68 [92%]); Grade 3-4 cytokine release syndrome was reported in 6 (8%) patients and grade 3-4 immune effector cell associated neurotoxicity syndrome was reported in 13 (18%) patients. ICU level of care was needed in 22 (30%) patients and 2 patients (3%) developed hemophagocytic lymphohistiocytosis-like syndrome. Sixty patients (87%) achieved an objective response and 34(49%) achieved a complete response. The 1-year OS was 66% (53-81) in patients who had ENI vs. 72% (54-97) in those without ENI (p=0.82); 1-year relapse rates were at 39% (20-54) vs. 36% (10-54) (p=0.95) for patients with ENI vs. those without ENI. No difference was noted between the two groups regarding progression-free survival and non-relapse mortality (NRM). No difference in outcomes was observed when patients who had GI involvement as the only site of ENI or in combination with other sites of ENI were compared to those who did not have GI involvement as one of the sites of ENI. Elevated LDH at the time of CART (HR 2.27 [95% CI 1.05-4.94], p=0.03), development of any grade ICANS (HR 2.77 [95% CI 1.27-6.04], p=0.01) and requirement for ICU level of care (HR 3.25 [95% CI 1.54-6.86], p=0.002) adversely affected OS; the impact of elevated LDH on OS remained significant in multivariate models (HR 2.34 [95% CI 1.05-5.27], p=0.04). Development of any grade CRS was associated with a decreased risk of relapse (HR 0.25 [95% CI 0.11-0.56], p=<0.001) and the requirement of ICU stay adversely affected NRM (HR 2.27 [95% CI 1.05-4.94], p=0.032). Conclusion These results suggest that ENI does not appear to be predictive of long-term outcomes in the setting of CART therapy. Patients who had ENI appeared to derive equal benefit from CART therapy. GI involvement as a site of ENI has been known to be associated with worse survival when compared to other sites of ENI but we did not observe any difference in this subgroup also. Evolving predictive models and/or biomarkers that take in account the dynamics of the interaction between the malignant and CART cells might help better inform prognostication in the current era.

Introduction: Chimeric antigen receptor T-cell therapy (CAR-T) has revolutionized the treatment of non-Hodgkin lymphoma (NHL). Despite having an increased risk of NHL, patients with pre-existing autoimmune disease (AID) were excluded from pivotal CAR-T trials due to concerns that CAR-T may exacerbate AID. As a result, there are limited data on the safety and efficacy of CAR-T for NHL in patients with AID. Interestingly, there is also growing evidence that CAR-T can be therapeutically effective for AID, such as in the treatment of systemic lupus erythematosus (SLE). As CAR-T utilization for NHL increases, it is essential to characterize the safety and efficacy of this potentially curative therapy in patients with AID. This study aimed to evaluate the impact of AID on outcomes in patients treated with commercial CD19-targeted CAR-T for NHL. Methods: Following Institutional Review Board approval, we conducted a retrospective analysis of all patients who were treated with commercial CD19-targeted CAR-T for NHL and had a pre-existing AID across the Mayo Clinic Enterprise (Arizona, Florida, and Minnesota) between January 2018 and May 2023. Variables collected included age, gender, NHL type, AID type, and CAR-T product. Efficacy outcomes, including response rates at 6 and 12 months after CAR-T, were collected. Toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), were collected and analyzed. Our chart review for AID included SLE, sarcoidosis, ulcerative colitis, celiac disease, pernicious anemia, Crohn's disease, psoriasis, Sjogren's syndrome, hypothyroidism (Hashimoto's disease), hyperthyroidism (Graves' disease), rheumatoid arthritis (RA), vasculitis, scleroderma, and mixed connective tissue disease (MCTD). Results: A total of 235 patients who received commercial CD19-targeted CAR-T for NHL across the Mayo Clinic Enterprise were identified (Table 1). Of these 235 patients, 27 had a pre-existing AID and 208 did not. The median age was 66 years (range 39-81) for patients with AID and 59 years (range 18-88) for patients without AID. Over half of the patients were male (59% of patients with AID and 51% of patients without AID). The most common NHL type was diffuse large B cell lymphoma (41% of patients with AID and 56% of patients without AID). Most patients received axicabtagene ciloleucel (85% of patients with AID and 84% of patients without AID). The most common AID was hypothyroidism (81%, n=22), although other conditions were also identified, including RA (11%, n=3), SLE (4%, n=1), pulmonary sarcoidosis (4%, n=1), psoriasis (4%, n=1), and MCTD (4%, n=1). Two patients had more than one AID. Median follow-up was 18 months (range 1-36) for patients with AID and 14 months (range 2-49) for patients without AID. Six months after CAR-T, the complete response (CR) rate was 77.2% and 45.1% in patients with AID and without AID, respectively (p=0.0042). Twelve months after CAR-T, the CR rate was 50% and 31.4% in patients with AID and without AID, respectively (p=0.0801). CRS of any grade occurred in 78% and 88% of patients with and without AID, respectively. ICANS of any grade occurred in 41% and 54% of patients with and without AID, respectively. Conclusion: AID did not appear to adversely impact the safety or efficacy of CAR-T for NHL. Limitations of our study include the small number of patients with AID and the fact that the most common AID was hypothyroidism. Larger studies are warranted to confirm these findings. Additional data are needed to characterize the impact of CAR-T for NHL on AID outcomes and to describe the effect of disease-modifying antirheumatic drugs on NHL outcomes after CAR-T.

While acknowledging that newer therapies have improved survival rates in chronic lymphocytic leukemia (CLL), patients with high-risk disease features are at an increased risk of treatment failure. Allogeneic hematopoietic cell transplantation (allo-HCT) was traditionally offered as front-line consolidation in high-risk CLL; however, with the emergence of targeted therapies like Bruton tyrosine kinase (BTK) and B-cell lymphoma 2 (BCL-2) inhibitors, the role of allo-HCT has been relegated to later stages of the disease. Patients with relapsed/refractory (R/R) CLL who have failed both BTK and BCL-2 inhibitors represent a therapeutic challenge owing to a poor prognosis. Chimeric antigen receptor T-cell (CAR T) therapies targeting CD19 have improved response rates and overall survival in various types of R/R B-cell non-Hodgkin lymphomas. For CLL, no approved CAR T-cell therapies are yet available. Emerging data appear to show a therapeutic benefit of CAR T-cell therapy in patients with R/R CLL, even after failing an allo-HCT.