FIGURE 5. Impact of anti-ICOS-mAb administered at tracer dose on in vivo persistence and anti-tumor activity of mCD19.28z CAR T cells.

(A-B) Expansion of Luc+ mCD19.28z CAR T cells in tumor bearing mice treated on day 5 with ICOS-mAb (A, upper panels; B, continuous lines) or appropriate isotype control (A, lower panels; B, dashed lines), administered at a dose similar to that employed for PET/CT studies (10 μg/mouse, representing upper limit of tracer dose). Data shown are from one experiment representative of two independent experiments with 4–5 mice per group in each experiment. (C) Overall survival of mCD19.28z CAR T cell treated (CAR, red lines) or not treated (NT, black lines) mice. At day 5, mice were randomized to receive intravenous administration of ICOS-mAb (continuous lines) or appropriate isotype control (dashed lines) at a dose similar to the ones employed for PET/CT studies (10 μg/mouse, representing the upper limit of tracer dose). Results are pooled from two independent experiments with a total of 9–10 mice per group. Survival curves were plotted using the Kaplan-Meier method and compared by log-rank test.