Cyclic peptides for protection against respiratory syncytial virus

The present invention relates to a cyclic peptide, a conjugate comprising said cyclic peptide and a lipopeptide building block, a bundle of said conjugates, a synthetic virus-like particle comprising at least one bundle of conjugates and pharmaceutical compositions comprising the same. The present invention further relates to said cyclic peptide, said conjugate said bundle of conjugates, said synthetic virus-like particle and said pharmaceutical compositions for use as a medicament, preferably for use in a method for preventing of an infectious disease or reducing the risk of an infectious disease, more preferably for use in a method for preventing or reducing the risk of an infectious disease associated with or caused by a respiratory syncytial virus. In particular, the present invention relates to a cyclic peptide, wherein said cyclic peptide comprises an amino acid sequence (I), wherein said amino acid sequence (I) comprises the following amino acid sequence: X1-X2-X3-C4-X5-X6-X7-C8-X9-X10-X11-P12-I13-T14-N15-D16-Q17-K18-K19-L20-C21- X22-X23-X24-C25-X26-X27-X28-X29-X30 (SEQ ID NO: 1), wherein X1, X2, X3, X5, X6, X7, X9, X10, X11, X22, X23, X24, X26, X27, X28 and X29 are independently of each other an amino acid; C4, C8, C21 and C25 are independently of each other cysteine; P12 is proline; I13 is isoleucine; T14 is threonine; N15 is asparagine; D16 is aspartic acid; Q17 is glutamine; K18 and K19 are independently of each other lysine; L20 is leucine; and X30 is an amino acid or a deletion, wherein said cysteines C4 and C25 form a first disulfide bond and said cysteines C8 and C21 form a second disulfide bond.