CD33 and acute myeloid leukemia: The EORTC-GIMMEMA AML-19 trial showed that GO improved outcomes in patients with AML and CD33 blast expression greater than 80% (47), whereas, in the ALFA-0701 study, a high expression of CD33 in leukemic blasts (more than 30% of cells) did not show any effect on EFS or RFS (32).