CAR T-cell progenitor exhausted phenotype and in vivo re-expansion in the blood with repeated dosing of durvalumab after JCAR014. (A) Aliquots of the infusion products (n = 26) and blood collected after CAR T-cell infusion (expansion, n = 26; contraction, n = 21; day 28, n = 12) were analyzed by flow cytometry. Percentage of PD-1⁺, TCF-1⁺, and PD-1⁺TCF-1⁺ CD3⁺ CAR T cells at each timepoint are shown. Figures show mean ± standard error of the mean. (B) CAR T-cell counts in the blood by qPCR in patients treated with JCAR014 in combination with durvalumab who experienced in vivo re-expansion of CAR T cells. Arrowheads on the x-axis indicate the time of durvalumab doses. Arrows show re-expansion events. Horizontal dashed lines show the qPCR assay limit of detection.