Peptide linkers for improved oligonucleotide delivery

An oligonucleotide-peptide-carrier conjugate wherein the oligonucleotide, peptide and carrier moieties are covalently linked to one another, and wherein:

• the oligonucleotide is selected from a group consisting of antisense oligonucleotide, antigene oligonucleotide, protein binding oligonucleotide and ribozyme which selectively binds to a desired sequence of RNA, DNA or protein in a target cell, and which by binding to the desired RNA, DNA or protein sequence brings about a desired therapeutic effect, the oligonucleotide optionally being modified relative to naturally occurring oligonucleotides to increase binding to the desired RNA, DNA or protein sequence or to increase resistance to nuclease enzymes;
• the peptide is cleavable by protease enzymes within the lysosomes of a target cell, and
• the carrier is a lysosomotropic carrier which is capable of facilitating transport of the oligonucleotide-peptide-carrier conjugate into the target cell.