Fusion respiratory syncytial virus inhibitors and use thereof

A compound consisting of the following amino acid sequence:

• Xaa1 Xaa2 Xaa3 Xaa4 Xaa5 Xaa6 Xaa7 Xaa8 Xaa9 Xaa10 Xaa11Xaa12 Xaa13 Xaa14 Xaa15 Xaa16 Xaa17 Xaa18 Xaa19 Xaa20 (SEQ ID NO:
• 1), wherein Xaa1, Xaa6, Xaa14 and Xaa18 are independently selected from any amino acid;
• Xaa2, Xaa4, Xaa5 and Xaa19 and are independently selected from any amino acid or a cross-linked amino-acid;
• Xaa3, Xaa7, Xaa9, Xaa10, Xaa16, Xaa17 and Xaa20 are independently an apolar amino acid;
• Xaa8 is a cross-linked amino-acid;
• Xaa11 and Xaa12 are independently selected from a polar amino acid and a cross-linked amino-acid;
• Xaa13 is Serine and Xaa15 is selected from a polar amino acid and a cross-linked amino-acid, wherein the peptide contains a total of two cross-linking bridges, each between two cross-linked amino acids spaced by 2 or three amino-acids (i, i+3 and/or i, i+4 staples);
• as well as pharmaceutically acceptable salts, pharmaceutically active variants thereof and any geometrical isomers thereof.