Increased Lifespan with Altered Sequence of Administration of BCNU and Cytoxan in L1210 Leukemic Mice

Abstract

L1210 leukemic mice were treated with a series of doses of Cytoxan (Cyt) at 4- or 5-day intervals. In each experiment a high dose of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) was substituted for a regularly scheduled dose of Cyt. Early BCNU substitution resulted in longer survival. This was most evident with the highest doses of BCNU. Early administration of a high priming dose of BCNU lowered the tumor cell population and may have increased the percentage of cells in cycle, so that scheduled doses of Cyt killed the cells more effectively.