AR-67 (formerly DB-67) (7-t-butyldimethylsilyl-10-hydroxycamptothecin) is a third generation analog engineered to be blood stable and highly potent. Its enhanced stability results from two factors: (1) AR-67 (formerly DB-67) is highly lipophilic, partitioning into lipid bilayers, thus protecting it from hydrolysis in the aqueous milieu of the bloodstream, and (2) the 10-hydroxy functionality of the drug effectively ablates the high affinity interactions of the carboxylate drug form with albumin, which has been previously shown to diminish the levels of the active lactone species in the circulation.