Alternative oxygen therapeutics: products, status of clinical trials, and future prospects

Alternative oxygen therapeutics are oxygen carriers that can potentially replace red blood cell transfusion in clinical instances in which banked blood is unavailable or unsafe. Most of the candidate solutions have been based on hemoglobin, derived from animals, outdated banked human blood, or recombinant systems. Other solutions are based on perfluorocarbons. In contrast to hemoglobin, which chemically binds oxygen, perfluorocarbons carry oxygen as a dissolved gas. Most of the products of either category developed over the past two decades have failed attempts at regulatory approval for clinical use, but their development has led to a large body of research that has defined the way oxygen is normally delivered to tissues. From this research, a new generation of products is emerging, designed specifically to target oxygen to the tissues in most need. It is possible that one or more of the earlier products may be approved by regulatory agencies in 1 or 2 years. However, a universally compatible and safe product most likely will be unavailable for several more years.