Patent ID: 7402556

Claim:
A pharmaceutical composition comprising: (1) A compound comprising: (a) a therapeutic agent capable of entering a target tumor cell, wherein said therapeutic agent is daunorubicin or doxorubicin and plasmin is present in the extracellular vicinity of the target tumor cell; (b) an oligopeptide having the formula (AA x ) m -(AA y ) n (SEQ ID NO:1) wherein: (AA x ) m is a plasmin substrate and each AA x independently represents an amino acid; each AA y independently represents an amino acid selected from the group consisting of Ile, Leu, Phe, and Val; m is an integer from 2-4; and n is an integer from 1-2; (c) a stabilizing group; and (d) optionally, a linker group not cleavable by plasmin; wherein the oligopeptide is directly linked to the stabilizing group at a first attachment site of the oligopeptide and the oligopeptide is directly linked to the therapeutic agent or indirectly linked through the linker group to the therapeutic agent at a second attachment site of the oligopeptide; wherein the stabilizing group hinders cleavage of the oligopeptide by enzymes present in whole blood; and wherein the compound is cleaved by plasmin under physiological conditions; and (2) a pharmaceutically acceptable carrier.