Our goal in developing a liver assist device is to provide liver support and improve the metabolic state of the patient so that the native liver has the opportunity to regenerate. Failing this, the patient should at least remain in satisfactory health so that liver transplantation can be performed safely. We have no idea how much metabolic support will be required to sustain life, but we have a set a goal of 20% of the normal hepatocyte mass. Our initial results suggest that this is an appropriate number, and a clinical trial to determine safety and efficacy is under way at the Texas Medical Center.