Expansion of CAR T cells following 1 to 3 cycles of NKTR-255. Flow cytometry measurement of patient CAR T cells in the blood after infusion. Persistence of (A) CD8 CAR T cells as a percentage of total CD8 T cells. (B) CD3 CAR T cells as a percentage of total CD3 T cells. (C) CD4 CAR T cells as a percentage of total CD4 T cells. Data are presented as percentages ± SEM by days post-NKTR-255 treatment. Green symbol, placebo; blue symbol, NKTR-255; and inverted triangle, NKTR-255 administration. SEM, standard error of the mean.