Table 2.

Summary of Low-Level CAR⁺ Cell Persistence and Time Points When CAR⁺ Cells Were Last Detected

Patient	Last Time Point after Infusion That Blood CAR+ Cells Were Detectable by qPCR	Limit of Detection in Each Patient (%)
2	CAR+ cells last detected 5 months after infusion	0.004
7	CAR+ cells last detected 4 months after infusion	0.005
8	CAR+ cells still detectable at a level of 0.08% 39 months after CAR T cell infusion prior to being removed from the study to receive allogeneic stem cell transplantation for myelodysplastic syndrome	0.017
9	CAR+ cells still detectable at a level of 0.03% prior to going off-study to receive standard lymphoma therapy 3 months after infusion	0.005
11	CAR+ cells still detectable at a level of 0.06% prior to going off-study to receive standard lymphoma therapy 2 months after CAR T cell infusion	0.020
14	CAR+ cells last detected 3 months after infusion	0.005
15	CAR+ cells still detectable at a level of 0.02% 43 months after CAR T cell infusion	0.004

CAR⁺ cell levels are given as a percentage of total PBMCs that contained the CAR gene. CAR gene levels were determined by qPCR. The limit of detection is different in each patient because an individual PCR standard curve was made for each patient by diluting DNA from each patient’s infused CAR T cells in the patient’s pretreatment peripheral blood mononuclear cell DNA.