Fig. 3

Assessment of Consistency of Vector Copy Number Measured by ddPCR. Anti-BCMA-CAR T cell vector copy number was assessed by ddPCR and assay consistency was assessed over time and among laboratory staff performing the assay. a Two different anti-BCMA-CAR T cell samples were tested by the same person prior to cryopreservation and after 3 weeks and 6 weeks of storage at -80 °C. Sample 1 had a mean vector copy number of 2.30 ± 0.08 copies/cell with a CV of 0.04 and Sample 2 had a mean of 1.67 ± 0.05 copies/cell with CV of 0.03. The P-value of a Two-way ANOVA analysis comparing vector copy numbers observed across time was 0.11. b Three different anti-BCMA-CAR T samples (fresh or cryopreserved) were tested by 3 different staff working in the same laboratory. Sample 1 had a mean of 2.30 ± 0.09 copies/cell with a CV of 0.04, Sample 2 had a mean of 1.64 ± 0.03 copies/cell with a CV of 0.02, and Sample 3 had a mean of 0.97 ± 0.02 copies/cell with a CV of 0.02. The P-value of a two-way ANOVA analysis comparing the vector copy numbers observed by each technician was 0.22