Influence of Adipose Tissue Distribution, Sarcopenia, and Nutritional Status on Clinical Outcomes After CD19 CAR T-cell Therapy.

Although CD19-directed chimeric antigen receptor T-cell therapy (CD19.CAR-T) has proven clinical efficacy for multiple refractory B-cell malignancies, over 50% of patients ultimately relapse. Recent evidence has underlined the critical role of the host in determining treatment responses. In this retrospective observational study of 106 patients with relapsed/refractory large B-cell lymphoma receiving standard-of-care CD19.CAR-T, we analyzed the impact of immunometabolic host features and detailed body composition measurements on post-CAR T clinical outcomes. We extracted muscle and adipose tissue distributions from prelymphodepletion CT images and assessed laboratory-based immuno-nutritional scores. Early responders displayed increased total abdominal adipose tissue deposits (TAT: 336 mm3 vs. 266 mm3, P = 0.008) and favorable immuno-nutritional scores compared to nonresponding patients. On univariate Cox regression analysis, visceral fat distribution, sarcopenia, and nutritional indices significantly impacted both progression-free (PFS) and overall survival (OS). Patients with a low skeletal muscle index (SMI; e.g.<34.5), a sarcopenia indicator, exhibited poor clinical outcomes (mOS 3.0 months vs. 17.6 months, log-rank P = 0.0026). Prognostically adverse immuno-nutritional scores were linked to inferior survival [low PNI: HROS, 6.31; 95% confidence interval (CI), 3.35-11.90; P < 0.001]. In a multivariable analysis adjusting for baseline Eastern Cooperative Oncology Group performance status, C-reactive protein, and lactate dehydrogenase, increased TAT was independently associated with improved clinical outcomes (adjusted HROS, 0.27; 95% CI, 0.08-0.90; P = 0.03). We noted particularly favorable treatment outcomes in patients with both increased abdominal fat and muscle mass (TAThigh/SMIhigh: 1-year PFS 50%, 1-year OS 83%). These real-world data provide evidence for a role of body composition and immuno-nutritional status in the context of CD19.CAR-T and suggest that the obesity paradox may extend to modern T cell-based immunotherapies. See related Spotlight by Nawas and Scordo, p. 704.

RIG-I-based immunotherapy enhances survival in preclinical AML models and sensitizes AML cells to checkpoint blockade.

Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic immune receptor sensing viral RNA. It triggers the release of type I interferons (IFN) and proinflammatory cytokines inducing an adaptive cellular immune response. We investigated the therapeutic potential of systemic RIG-I activation by short 5'-triphosphate-modified RNA (ppp-RNA) for the treatment of acute myeloid leukemia (AML) in the syngeneic murine C1498 AML tumor model. ppp-RNA treatment significantly reduced tumor burden, delayed disease onset and led to complete remission including immunological memory formation in a substantial proportion of animals. Therapy-induced tumor rejection was dependent on CD4+ and CD8+ T cells, but not on NK or B cells, and relied on intact IFN and mitochondrial antiviral signaling protein (MAVS) signaling in the host. Interestingly, ppp-RNA treatment induced programmed death ligand 1 (PD-L1) expression on AML cells and established therapeutic sensitivity to anti-PD-1 checkpoint blockade in vivo. In immune-reconstituted humanized mice, ppp-RNA treatment reduced the number of patient-derived xenografted (PDX) AML cells in blood and bone marrow while concomitantly enhancing CD3+ T cell counts in the respective tissues. Due to its ability to establish a state of full remission and immunological memory, our findings show that ppp-RNA treatment is a promising strategy for the immunotherapy of AML.