Comparison of immune reactivity and pharmacokinetics of two hepatitis B immune globulins in patients after liver transplantation

Hepatitis B virus (HBV) immune globulin (HBIg) administration will prevent HBV graft reinfection in HBV patients after orthotopic liver transplantatio n (OLT), Ho However, the expenditure for such prophylaxis is extremely high ranging between $2,000 to $10,000 per month in various countries for an un defined period and presumably for life. As a consequence, there is a need f or introduction of additional and less expensive modes of treatment, In a p reliminary clinical trial a new HBIg preparation has been shown to induce l onger lasting levels of circulating antibodies to hepatitis B surface antig en (anti-HBs) in patients after OLT compared with previous experience with conventional HBIg preparations. In the present study the pharmacokinetics o f this new HBIg, OMRI-Hep-B, were studied and compared with a conventional, licensed preparation, Hepatect. Fifteen post-OLT patients (2-8 years post- OLT, 18-62 years of age, 6 men, 9 women) were treated intravenously with 49 doses of OMRI-Hep-B or Hepatect given at least once, alternately, at 10,00 0 to 14,000 units per injection ( approximate to 130 IU/kg body weight). Th e new HBIg was well tolerated and no adverse effects were observed, Adminis tration of OMRI-Hep-B was shown to induce high and long-lasting levels of c irculating anti-HBs antibodies and greater areas under the curve (AUC) comp ared with the conventional preparation. Thus, anti-HBs half-life was 22 +/- 1.3 days for OMRI-Hep-B recipients and 13 +/- 1.3 days for Hepatect recipi ents (P < .001), Time to reach trough anti-HBs levels of 150 mIU/mL was sig nificantly longer after administration of OMRI-Hep-B than after Hepatect (7 9 +/- 4.5 and 52 +/- 3.8 days, respectively; P < .001). In summary, the pha rmacokinetic profile of the new HBIg, and in particular its prolonged elimi nation half-life, may reduce the cost of administration by approximately 30 % and improve the quality of life of patients by extending the interval bet ween repeated immune globulin injections.