CD33 and leukemia: Recent studies examining the bi-specific engager AMG 330, which targets the leukemia antigen CD33, concluded that the in vitro activity of this agent correlated with the number of autologous T-cells present in patient leukemia samples, and that effective autologous T-cell redirected lysis could be detected at E:T ratios as low as 1 T-cell to more than 2,700 AML blasts.