Etoposide and teniposide in the treatment of acute leukemia.

Etoposide and teniposide are semi-synthetic glucoside derivatives of podophyllotoxin with a documented anti-tumour activity in various types of malignant diseases. It was an early observation that these epiphodophyllotoxins were efficacious in hematological malignancies such as lymphomas and leukemias. In this report the clinical evidence supporting the activity of etoposide and teniposide in acute lymphoblastic (ALL) and non-lymphoblastic leukemia (ANLL) is reviewed. Unlike podophyllotoxin, etoposide and teniposide do not appear to affect microtubular function nor arrest cells in mitosis. These epiphodophyllotoxins, like other DNA intercalating agents, have topoisomerase II as their target. Most studies with etoposide have been performed in ANLL and with teniposide in ALL. This choice seems to be rather arbitrary and is better explained by traditional reasons than actual study results. The data in acute leukemias are partly flawed by the absence of certain prospective comparative trials. However, the current information on etoposide clearly shows that this agent has substantial activity in ANLL and may well be incorporated into front-line regimens and the same is true for teniposide in the treatment of ALL. Nevertheless, based on available literature, there are no convincing data to the author's mind to support that one of these agents is superior to the other in the treatment of acute leukemias.