possible stabilized forms are cyclic peptides or polypeptides like cyclic vip or vyclic pacap fusion proteins preferably fc fusion proteins or pegylated polypeptides for example pegylated vip or pacap methods for manufacturing such polypeptides are well known in the art polypeptides and proteins may be protected against proteolysis by the attachment of chemical moieties such attachment may effectively block the proteolytic enzyme from physical contact with the protein backbone itself and thus prevent degradation polyethylene glycol is one such chemical moiety which has been shown to protect against proteolysis sada et al j fermentation bioengineering 71 137 139 1991 in addition to protection against proteolytic cleavage chemical modification of biologically active proteins has been found to provide additional advantages under certain circumstances such as increasing the stability and circulation time of the therapeutic protein and decreasing immunogenicity u s pat no 4 179 337 abuchowski et al enzymes as drugs j s holcerberg and j roberts eds pp 367 383 1981 francis focus on growth factors 3 4 10 ep 0 401 384 the addition of polyethylene glycol increases stability of the peptides and polypeptides of this invention at physiological ph as compared to non pegylated compounds the pegylated polypeptide protein is also stabilized with regard to salts the term u201c fusion protein u201d means a compound especially a stabilized form consisting of a polypeptide according to the invention preferably vip or a vip derivative or analogue such as pacap which is fused to another peptide or protein such a protein is preferably an immunglobulin molecule more preferably a fragment thereof most preferably a fc portion of an igg molecule preferably an igg1 a fc vip fusion protein is described in.