Figure 3. CAR T-Cell Expansion and Correlations with Response and Adverse Events.

Serial blood samples were analyzed for chimeric antigen receptor (CAR) T-cell levels and serum biomarkers in all 101 patients who were treated with axi-cel, as described previously.21 Panel A shows CAR T-cell expansion and persistence with median values and interquartile ranges (Q1 and Q3). Panel B shows the association between CAR T-cell expansion, which was measured as peak levels of CAR cells per microliter of blood, and the objective response rate, neurologic events, and the cytokine release syndrome. The peak factor change is shown for patients with a response as compared with those without a response, for those with neurologic events of grade 3 or higher, and for those with the cytokine release syndrome of grade 3 or higher. P values were calculated by means of the Wilcoxon rank-sum test. Panel C shows serum biomarkers (interleukin-2, granulocyte–macrophage colony-stimulating factor [GM-CSF], and ferritin) that were associated only with neurologic events and not with the cytokine release syndrome. The peak value is defined as the maximum level of the cytokine after baseline. The peak factor is the value in patients with neurologic events of grade 3 or higher versus those with events of grade 0 to 2. Adjusted P values were calculated with the use of Holm’s procedure after multiple testing by means of the Wilcoxon rank-sum test. In Panels B and C, the horizontal line within each box represents the median, and the lower and upper borders of each box represent the 25th and the 75th percentiles, respectively, and the I bars represent the minimum and maximum range.