Abstract: This invention pertains to certain enzyme (CPG2) activated self-immolative nitrogen mustard prodrugs, which are useful in enzyme prodrug therapy (EPT), such as ADEPT and GDEPT, for the treatment of proliferative conditions, such as cancer, and which have the following formula: wherein: RN is independently C1-7alkyl; X1 is independently —I, —Br, or —Cl; X2 is independently —I, —Br, or —Cl; the group —N(CH2CH2X1)(CH2CH2X2) is independently attached at the 2-position or at the 4-position; each RG is independently —H or an ester substituent; n is independently an integer from 0 to 4; each RP, if present, is independently a phenyl substituent; m is independently an integer from 0 to 4; each RM, if present, is independently a mustard substituent; and pharmaceutically acceptable salts, solvates, amides, and esters thereof.