Although we found higher RR in the anti-CD19/CD22 subgroup, the overall RR of this therapy in r/r B-ALL was 0.31 with a moderate heterogeneity among studies (95% CI = 0.27, 0.36; p < 0.01; I2 = 66.94) (Figure 3(A)). This evidence concerns the gene CD22 and acute lymphoblastic leukemia.