BACKGROUND The need to find a safe, effective liver support system for patients with fulminant hepatic failure (FHF) continues to be unmet. A system using immortalized human hepatocytes was originally developed in the early 1990s. A modified version of the initial extracorporeal liver-assist device (ELAD) was recently placed into an initial clinical trial at the University of Chicago. The goal of this study was to determine the safety profile of the device at one center before broadening the study to other sites. METHODS Patients who were diagnosed with FHF and admitted to the University of Chicago were eligible for the ELAD study. Informed consent was obtained, and patients received continuous ELAD therapy until and throughout transplantation. Data were prospectively collected and subsequently analyzed. RESULTS Five patients were treated with the device. All patients successfully underwent transplantation. Four of the five patients survived to the 30-day endpoint of the study. There were no biomechanical problems identified. The patients' hemodynamic conditions did not deteriorate during treatment. The adult patients' clinical courses appeared to stabilize while connected to the ELAD (mean arterial pressure range 80-97, mean 88.6; cerebral perfusion pressure range 62-88, mean 76.5). Patient 4 experienced remarkable improvement during ELAD therapy: elimination of phenylephrine, reduction of dopamine from 20 microg/min to 5 microg/min, and reduction of respiratory support from 100% O2, 10 cm positive end-expiratory pressure to 60% O2, and 5 cm H2O positive end-expiratory pressure. The device continued to be metabolically active throughout the study period as documented by oxygen use (mean O2 change from sampling port before cartridge to sampling port after cartridge for all patients treated = 55 mm Hg). CONCLUSIONS The patients tolerated treatment with the ELAD well. There were no unanticipated safety issues. The cells in the cartridges were metabolically active. All patients successfully underwent transplantation. The results from this single-institution experience indicates that larger randomized multicenter trials should proceed.