Novel therapeutic uses of alpha-1 antitrypsin: a window to the future.

Alpha-1 antitrypsin, a potent serine protease inhibitor, has been used as augmentation therapy in patients with alpha-1 antitrypsin deficiency for many years. Recent research into the diverse anti-inflammatory, immune-modulatory and tissue-protective actions of alpha-1 antitrypsin has raised the possibility of broadening the therapeutic spectrum of alpha-1 antitrypsin to include diseases other than alpha-1 antitrypsin deficiency. The purpose of the workshop was to summarize the results of basic investigations and, if available, clinical studies in which the effects of alpha-1 antitrypsin were explored in relation to clinical conditions that are not associated with alpha-1 antitrypsin deficiency. Included among these are type 1 diabetes, cell/organ rejection, viral infection, cystic fibrosis, bronchiectasis/COPD, heart failure, Crohn's disease and connective tissue diseases. Although the therapeutic utility of alpha-1 antitrypsin in these conditions remains to be established, the existing data suggest that this protein eventually will become a treatment option in several diseases some of which are not rare. At present, only human plasma-derived alpha-1 antitrypsin is available for clinical use. Given the limited supply and the potential for extended use of this product, there will be a need for new formulations of alpha-1 antitrypsin in the future. Therefore, the prospect of finding new sources and airway delivery methods of alpha-1 antitrypsin were also discussed. The presentations at the meeting addressed the scientific basis for new clinical applications of alpha-1 antitrypsin and the regulatory requirements needed to bring this therapeutic protein to a wider range of patient populations.