The present invention provides a compound, preferably
a peptide, having the following characteristics:a) consisting of 9 amino acids in a linear arrangement;b) of those 9 amino acids, 5 are cationic and 4 have a lipophilic R group;c) at least one of said 9 amino acids is a non-genetically coded
amino acid (e.g. a modified derivative of a genetically coded
amino acid); and optionallyd) the lipophilic and cationic residues are arranged such that there are no more than two of either type of residue adjacent to one another; and further optionallye) the molecule comprises two pairs of adjacent cationic amino acids and one or two pairs of adjacent lipophilic residues;for use in the treatment of a tumour by combined, sequential or separate administration with an
immune checkpoint inhibitor. The present invention further provides pharmaceutical packs or compositions comprising these active agents and methods of treating a tumour comprising administration of these active agents. Also provided are the peptidic compounds as defined above for use in the destabilisation of a mitochondrial membrane, and a peptidic compound as defined above and an
immunotherapeutic agent as a combined preparation for separate, simultaneous or sequential use in treating tumours.