HepaGam B is recommended in patients who have no or low levels of viral replication at the time of liver transplantation. The clinical trial evaluating HepaGam B in liver transplant patients selected patients with no or low replication status only. HepaGam B therapy has not been evaluated in combination with antiviral therapy post- transplantation.

Comparative Bioavailability Studies

The pharmacokinetic profile of HepaGam B after intramuscular injection of 0.06 mL/kg in two 84- day pharmacokinetics studies⁸, 70 volunteers were administered HepaGam B. The mean peak concentrations (Cmax) in both studies were comparable and occurred within 4-5 days of administration. Both studies demonstrated mean elimination half-lives (t_½) following i.m. administration of 22 to 25 days. The mean clearance rate was 0.21 to 0.24 L/day and the volume of distribution was approximately 7.5 L. Thus, HepaGam B demonstrates pharmacokinetic parameters similar to those reported by Scheiermann and Kuwert²¹.

The maximum concentration of anti-HBs achieved by HepaGam B was consistent with that of two other licensed Hepatitis B Immune Globulin (Human) products when compared in the two pharmacokinetic trials8. Comparability of pharmacokinetics between HepaGam B and a commercially available hepatitis B immune globulin product administered i.m. indicates that similar efficacy of HepaGam B should be inferred.

REFERENCES

1. CDC. A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States. Recommendations of the Advisory Committee on Immunization Practices (ACIP). Part 1: Immunization of infants, children, and adolescents. MMWR 2005; 54(RR-16): 1-32.

2. CDC. A comprehensive immunization strategy to eliminate transmission of hepatitis B virus infection in the United States. Recommendations of the Advisory Committee on Immunization Practices (ACIP). Part 2: Immunization of adults. MMWR 2006; 55(RR-16): 1-33.

5. Samuel D, Muller R, Alexander G, Fassati L, Ducot B, Benhamou JP et al. Liver transplantation in European patients with the hepatitis B surface antigen. N Engl J Med 1993; 329(25):1842-1847.

8. Unpublished data on file.

13. Grady GF, Lee VA. Hepatitis B immune globulin - prevention of hepatitis from accidental exposure among medical personnel. N Engl J Med 1975; 293:1067- 70.

14. Seeff LB, et al. Type B hepatitis after needle-stick exposure: Prevention with hepatitis B immune globulin. Ann Int Med 1978; 88: 285-93.

15. Krugman S, Giles JP. Viral hepatitis, type B (MS-2-strain). Further observations on natural history and prevention. N Engl J Med 1973; 288: 755-60.

16. Hoofnagle JH, et al. Passive-active immunity from hepatitis B immune globulin. Ann Int Med 1979; 91:813-8.

17. Shouval D, Samuel D. Hepatitis B immune globulin to prevent hepatitis B virus graft reinfection following liver transplantation: a concise review. Hepatology 2000; 32(6):1189-1195.

18. Sawyer RG, McGory RW, Gaffey MJ, McCullough CC, Shephard BL, Houlgrave CW et al. Improved clinical outcomes with liver transplantation for hepatitis B-induced chronic liver failure using passive immunization. Ann Surg 1998; 227(6): 841-50.

19. Schilling R, Ijaz S, Davidoff M, Lee JY, Locarnini S, Williams R, Naoumov NV. Endocytosis of hepatitis B immune globulin into hepatocytes inhibits the secretion of hepatitis B virus surface antigen and virions. J Virol 2003;77(16):8882-92.

20. CDC. Updated U.S. Public Health Service Guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for postexposure prophylaxis. MMWR 2001; 50(RR-11): 1-42.

21. Scheiermann N, Kuwert EK. Uptake and elimination of hepatitis B immunoglobulins after intramuscular application in man. Dev Biol Standard 1983; 54:347-55.

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