A composition of matter that includes at least one of the peptide sequences； Arg-Val-Ala-Val-Ile-Met-Gly-amide (DP-068) and Leu-Ala-Phe-Val-Leu-Arg-Lys-amide (DP-074). A pharmaceutical composition that includes peptides Arg-Val-Ala-Val-Ile-Met-Gly-amide (DP-068) and Leu-Ala-Phe-Val-Leu-Arg-Lys-amide (DP-074). Use of the peptides for preparation of a medicament for the treatment of a diseases characterized by A² fibrillogenesis. Use of an antibody directed against a peptide comprising Leu-Ala-Phe-Val-Leu-Arg-Lys-amide in the manufacture of a medicament for the treatment of a disease characterized by A² fibrillogenesis. Preferably where at least one amino acid of the peptide sequence is a D-amino acid.
