Abstract: A therapeutic agent which carries a peptide sequence containing a mammalian cell adhesion sequence can be used to inhibit or treat diseases associated with intracellular formation of protein fibrillar inclusions or aggregates, to inhibit the intracellular formation of protein fibrillar inclusions or aggregates, and to disaggregate pre-formed intracellular protein fibrillar inclusions or aggregates. Filamentous bacteriophage which displays a non-filamentous bacteriophage RGD cell adhesion sequence on its surface, but not an antibody or non-filamentous bacteriophage antigen other than said RGD cell adhesion sequence, is a preferred embodiment of such a therapeutic agent.