The therapeutic effectiveness of uracil mustard, 5 [bis (2 chloroethyl) amino] uracil, was evaluated by the Southwest Cancer Chemotherapy Study Group in children with metastatic Wilms's tumor. This clinical trial was conducted in accordance with the Group's "sensitivity spectrum" protocol for the systematic investigation of new agents against solid tumors of childhood.1
Uracil mustard, an oral alkylating agent, is a substituted mechlorethamine hydrochloride (nitrogen mustard). In comparative experiments on animal tumors, uracil mustard was more effective than either chlorambucil or nitrogen mustard.2,3 This enhanced activity is thought to be due to an increased uptake of the uracil mustard into the desoxyribonucleic acid molecule because of the carrier action of uracil. There is no evidence that it acts as a uracil antagonist. In human malignancies it has been shown to be effective against chronic leukemias, lymphomas, and, occasionally, carcinoma of the lung and ovary and other neoplastic diseases.4-8