Figure 3.

Peak expansion and day 28 persistence in patients who received cryopreserved versus fresh CAR T cells

The results of testing for peak expansion and persistence of cryopreserved and freshly infused anti-C22 CAR T cells are shown in (A)–(D) and of anti-CD19/CD22 bispecific CAR T cells in (E)–(H). (A) and (E) show peak in vivo expansion in peripheral blood expressed as the percentage of T cells expressing the CAR construct. (B) and (F) show peak in vivo expansion in peripheral blood expressed as the absolute number of CAR T cells per microliter. Please note different y-axes used in these panels due to vastly different expansion between the two CAR constructs. (C) and (G) show day 28 CAR T cell persistence in bone marrow expressed as percentage of T cells expressing the CAR construct. Anti-CD22 CAR T cells were measured by the expression of the CD22 CAR and anti-CD19/CD22 CAR T cells by the expression of the CD19 CAR. All patients receiving anti-CD22 CAR T cells (n = 40) and anti-CD19/22 CAR T cells (n = 19) were evaluated for peak expansion and day 28 (+/− 4 days) bone marrow persistence. In addition, (D) and (H) show peak expansion with patients grouped by baseline disease burden in the CD22 and the CD19/22 cohorts, respectively, demonstrating the relationship between expansion and disease burden especially in the CD19/22 cohort.