The present invention relates to novel agents, pharmaceutical compositions containing them, and theft use in therapy, particularly anti-microbial and anti-cancer therapy. In particular, the present invention relates to novel peptide-based compounds based on SEQ ID NO: 40 which have surprisingly been shown to have inhibitory effects on the growth and/or viability of cells, particularly bacterial and cancer cells. Also provided are therapeutic and non-therapeutic methods which include the use of peptides of the invention.