The progress in cancer chemotherapy since the 1940s has been tremendous with over 40 cytotoxic agents, excluding hormones, that have undergone clinical trials and been approved by the Food and Drug Administration (FDA). Preclinical drug development and clinical trials have made this progress possible. Several new agents that are either undergoing clinical trials or have recently been approved by the FDA include idarubicin, ICRF-187, piroxantrone, all-trans-retinoic acid, fludarabine phosphate, taxol, and suramin.