The anthracyclines daunorubicin (DNR) and doxorubicin (DOX) are among the most important drugs in the treatment of childhood acute lymphoblastic leukemia, however there are conflicting in vitro data about the comparative efficacy and equivalent doses of both anthracyclines. To address the question of in vivo efficacy of both anthracyclines, patients enrolled in the CoALL 07-03 trial were randomized to receive one single dose of either doxorubicin 30?mg/m(2) , daunorubicin 30?mg/m(2) , or daunorubicin 40?mg/m(2) upfront induction therapy.