Figure 3
From: SSTR2 as an anatomical imaging marker and a safety switch to monitor and manage CAR T cell toxicity
PEN-221 treatment mitigates CAR T-associated toxicity in vivo and elongates survival. (a) Schematic of the tricistronic lentiviral vector encoding the 2nd generation ICAM1-specific CAR (F292A-4-1BB-CD3ζ), human SSTR2 and human IL-12. Transgenes are separated by P2A and T2A ribosomal skipping sequences. F292A, a micromolar affinity I ___domain derived from LFA-1; CD8 hinge-TM, CD8 hinge and transmembrane domains; 4-1BB, 4-1BB costimulatory ___domain; CD3ζ, CD3ζ signaling ___domain. (b) Flow cytometry data showing CD3, CD4/CD8 subsets as well as CAR and SSTR2 expression detected by anti-cMyc and anti-SSTR2 antibodies. (c) Schematic of the ATC mouse model. Fluc-expressing 8505C cells (1 × 106/mouse) were implanted subcutaneously into the upper left flank of NSG and NSG-MHC-KO mice and treated 5 days later with 10 × 106 primary CAR T cells or left untreated (No T). When mice started to show symptoms of toxicity, 25 μg PEN-221 was intravenously administered every 3–4 days from day 20 to day 33. (d) Tumor growth was assessed by bioluminescence imaging on a weekly basis. (e) Tumor burden was estimated by the level of total body bioluminescence intensity. (f) Tumor volume was measured and plotted. Data represent mean ± SD of 5 mice per cohort. A two-way ANOVA with Tukey’s multiple comparisons test was used for statistical analysis. *, P < 0.05; **, P < 0.01; ns, not significant. (g) Kaplan–Meier survival curves. Statistical significance was determined by Log-rank (Mantel-Cox) test. *, P < 0.05; **, P < 0.01; ns, not significant.
