Polypeptides are susceptible to denaturation or enzymatic degradation in the blood, liver or kidney. Due to the low stability of some polypeptides, it has been required to administer polypeptide drugs in a sustained frequency to a subject in order to maintain an effective plasma concentration of the active substance. Furthermore, pharmaceutical compositions of therapeutic peptides preferably have a shelf-life of several years in order to be suitable for common use. However, peptide compositions are inherently unstable due to sensitivity towards chemical and physical degradation. In part, the invention provides SAP variant proteins, compositions, pharmaceutical preparations and formulations having a prolonged in vivo half-life, prolonged shelf-life, or rather increased in vitro stability, or increased manufacturing efficiency compared to human SAP. Advantages of increased plasma half-life include, but are not limited to, reducing the amount and/or frequency of dosing.
