The present invention relates to new vascular targeting peptides containing the retro- inverso peptide rGn, such peptides being characterized by peptide bond reversal and inversion of chirality of the aminoacids of the parent peptide NGR. The retro-inverso rGn peptides are able to target tumor vessels since they are effective ligands of CD13 receptor expressed in angiogenic endothelium. The present invention also relate to a new therapeutic strategy against cancer based on the use of conjugates of peptides containing rGn motif and a therapeutic moiety. The presence of the rGn motif allows a specific targeting to tumor vessels of the therapeutic moiety thus causing an increase in efficacy and a reduction of toxic effects.
