The instant invention provides compositions comprising a prodrug, the prodrug comprising a therapeutically active drug; and a peptide selected from the group consisting of the sequences: Ser-Ser-Lys-Tyr-Gln (SEQ ID NO:1); Gly-Lys-Ser-Gln-Tyr-Gln (SEQ ID NO:2); and Gly-Ser-Ala-Lys-Tyr-Gln (SEQ ID NO:3) wherein the peptide is linked to the therapeutically active drug to inhibit the therapeutic activity of the drug, and wherein the therapeutically active drug is cleaved from the peptide upon proteolysis by an enzyme having a proteolytic activity of prostate specific antigen (PSA). The invention further provides methods of making and using the claimed compositions.