• Proportion of participants who have graft loss or death [ Time Frame: Within 1 year of transplantation ] [ Designated as safety issue: Yes ]
  

• Proportion of participants who have graft loss or die [ Time Frame: Within 2 years after initiation of immunosuppression withdrawal ] [ Designated as safety issue: Yes ]
  
• Incidence of immunosuppression-related complications [ Time Frame: Throughout study participation ] [ Designated as safety issue: Yes ]
  
• Measures of tolerance induction [ Time Frame: At Year 1 post-transplant through end of study ] [ Designated as safety issue: No ]
  

Organ transplantation is a common procedure in hospitals, but organ rejection and serious side effects are potential problems for the patient. Alemtuzumab is a monoclonal antibody that binds to and depletes excess T cells in the bone marrow of leukemia patients. In this study, alemtuzumab will destroy the recipient's white blood cells (WBCs) at the time of transplantation. It is hoped that WBCs produced after alemtuzumab administration will recognize the transplanted liver as "self" and not reject the new liver.

Drugs that suppress the immune system, such as tacrolimus, have contributed to increased success of transplantation. However, to prevent organ rejection, transplant recipients need to take immunosuppressive drugs for the rest of their lives, and these drugs make patients more susceptible to infection, endangering their health and survival. Regimens that are less toxic to or can eventually be withdrawn from transplant recipients are needed. This study will evaluate the effects of two in-patient doses of alemtuzumab followed by maintenance antirejection medication given to liver transplant patients post-transplant. This study will also determine if post-transplant tacrolimus therapy can be slowly and safely tapered off and withdrawn a year after transplant. Participants in this study will be patients with end-stage liver disease who will undergo liver transplantation at the start of the study.

This study will last at least 2 years. Patients will undergo liver transplantation at the start of the study on Day 0. Patients will receive in-patient infusions of alemtuzumab on Days 0 and 4. Starting on Day 1, patients will receive oral cyclosporine, mycophenolate mofetil, and/or tacrolimus daily. Patients will be hospitalized for at least 1 week after transplantation. Because of suppression of patients' immune systems by alemtuzumab and these other immunosuppressants, they will also receive prophylactic medications for a minimum of 3 months after transplantation to prevent opportunistic infections.

There will be at least eight study visits; they will occur at Days 4, 7, and 14 and at Months 1, 3, 6, 9, and 12. Patients will have liver biopsies at Day 0 and Months 6 and 12. At Month 12, participants will have assessments and blood tests to determine if they meet certain criteria and are eligible to undergo tacrolimus tapering. Patients eligible for tapering will undergo a 12-month gradual withdrawal of tacrolimus; they will be followed for an additional 2 years, with study visits at Months 18, 24, 30, and 36. Patients ineligible for tacrolimus tapering will continue taking their antirejection medication for the duration of the study; they will be followed for an additional year, with study visits at Months 18 and 24.