Hepatitis B immune globulin for life versus limited use: I favor limited duration of therapy.

Abstract

The initial enthusiasm for performing orthotopic liver transplantation (OLT) on patients with chronic hepatitis B virus (HBV) infectionwas tempered in the early 1990s by a high rate of recurrent infection, with the subsequent development of severe recurrent hepatitis frequently leading to loss of the allograft.1 In the absence of effective therapy, recurrent infection, defined as the appearance after OLT of detectable hepatitis B surface antigen (HBsAg) in serum, occurred in 70% to 90%2 of patients who were HBsAg positive preoperatively. Subsequent histological findings of hepatitis were seen in most patients, including the lesion termed fibrosing cholestatic hepatitis.3 This lesion is marked by overexpression of HBV proteins in hepatocytes, with cellular swelling and cholestasis, but only minimal inflammation. These observations suggested that HBV may be directly cytopathic in the post-OLT setting. Fortunately, most patients who clear HBsAg after OLT have a normal liver on histological studies and a benign clinical course.2 Patients at greatest risk for developing recurrent HBV infection are those with chronic HBV infection and, in particular, detectable HBV DNA or hepatitis B e antigen in serum before OLT.2,4 Patients at lower risk for reinfection include patients with acute HBV infection and those coinfected with hepatitis D virus, which appears to suppress HBV replication. A major breakthrough came when several studies showed that hepatitis B immune globulin (HGIg) administered intravenously in high doses during and after OLT could substantially reduce the risk for reinfection, leading to improved survival rates.2,5-8 Using HBIg alone to prevent recurrent HBV infection was most effective in those at lower risk for recurrent infection, i.e., patients with hepatitis D virus coinfection or acute hepatitis B or those who were HBV DNA negative in serum.2,5 However, intravenous administration of HBIg is costly, i.e., currently $74,320 for eight daily doses of HBIg during the first week post-OLT and monthly thereafter and approximately $45,000 per annum after year 1 (local data). When used alone, it may be required for life. Late breakthroughs also have occurred in patients who develop a variety of mutations in the HBV S gene.9 For these reasons, there is an extreme need for true antiviral agents that might inhibit viral replication and prevent HBV reinfection when used pre-OLT. Several nucleoside analogues have been shown to meet such criteria.8,10,11 The first such agent, lamivudine, has been shown to markedly decrease the rate of HBV reinfection after OLT, even when administered alone.10,12 Lamivudine is very well tolerated and much less expensive than HBIg. The major limitation to its use is the development of resistance through viral mutation at the YMDD locus of the polymerase molecule.10,13,14 Resistance develops in up to 30% of transplant recipients by 1 year. Moreover, severe recurrent disease has occurred in patients after the development of viral breakthrough.11,13 Because of the problem of viral mutation leading to viral escape with the use of both lamivudine and HBIg, many programs have combined the use of lamivudine with HBIg.7,15,16 Neither the optimal dosage and treatment interval nor the utility of measuring antibody to HBsAg titers to monitor therapy in this setting have been established. However, it appears that much lower doses of HBIg are required when combined with lamivudine, and the rate of acquired viral resistance is much lower. Several groups have published excellent results using relatively low-dose HBIg administered intramuscularly, which reduces both the cost and side effects of HBIg.With such regimens, the rate ofHBV infection is down to 5% or less.7,15 Newer agents with antiviral activity against HBV include adefovir and entecavir. These agents are attractive in that they have activity against the YMDD mutant variants of HBV.11,13 In the future, we likely will use combinations of antiviral agents with differing sites of action to prevent HBV reinfection after OLT. In this current era, a key question is whether one needs to continue HBIg therapy for life. As stated, the use of HBIg adds substantially to the cost of performing OLT on patients with hepatitis B and, when adminisFrom the Liver Transplantation Program, University of Minnesota, Minneapolis, MN. Address reprint requests to John R. Lake, MD, University of Minnesota, Department of Medicine, 420 Delaware St, Box 36, Minneapolis, MN 55455. Telephone: 612-625-0684; FAX: 612-625-5620; E-mail: lakex009@umn.edu Copyright © 2002 by the American Association for the Study of Liver Diseases 1527-6465/02/0810-1016$35.00/0 doi:10.1053/jlts.2002.35978