Mechanism Of Action
Infection with hepatitis B virus can have serious consequences including acute massive hepatic necrosis and chronic active hepatitis. Chronically infected persons are at increased risk for cirrhosis and hepatocellular carcinoma.
Efficacy In Neonates
Protective efficacy with ENGERIX-B has been demonstrated in a clinical trial in neonates at high risk of hepatitis B infection.6,7 Fifty-eight neonates born of mothers who were both HBsAg-positive and hepatitis B “e” antigen (HBeAg)-positive were given ENGERIX-B (10 mcg/0.5 mL) at 0, 1, and 2 months, without concomitant hepatitis B immune globulin (HBIG). Two infants became chronic carriers in the 12-month follow-up period after initial inoculation. Assuming an expected carrier rate of 70%, the protective efficacy rate against the chronic carrier state during the first 12 months of life was 95%.
Efficacy And Immunogenicity In Specific Populations
ENGERIX-B (20 mcg/1 mL) given at 0, 1, and 6 months was evaluated in homosexual men 16 to 59 years of age. Four of 244 subjects became infected with hepatitis B during the period prior to completion of the 3-dose immunization schedule. No additional subjects became infected during the 18-month follow-up period after completion of the immunization course.
Adults with Chronic Hepatitis C
In a clinical trial of 67 adults 25 to 67 years of age with chronic hepatitis C, ENGERIX-B (20 mcg/1 mL) was given at 0, 1, and 6 months. Of the subjects assessed at month 7 (N = 31), 100% responded with seroprotective titers. The geometric mean antibody titer (GMT) was 1,260 mIU/mL (95% Confidence Interval [CI]: 709, 2,237).
Adults on Hemodialysis
Hemodialysis patients given hepatitis B vaccines respond with lower titers, which remain at protective levels for shorter durations than in normal subjects. In a clinical trial of 56 adults who had been on hemodialysis for a mean period of 56 months, ENGERIX-B (40 mcg/2 mL given as two 1-mL doses) was given at 0, 1, 2, and 6 months. Two months after the fourth dose, 67% (29/43) of patients had seroprotective antibody levels ( ≥ 10 mIU/mL) and the GMT among seroconverters was 93 mIU/mL.
Immunogenicity In Neonates
In clinical studies, neonates were given ENGERIX-B (10 mcg/0.5 mL) at 0, 1, and 6 months or at 0, 1, and 2 months of age. The immune response to vaccination was evaluated in sera obtained one month after the third dose of ENGERIX-B.
Among infants administered ENGERIX-B at 0, 1, and 6 months, 100% of evaluable subjects (N = 52) seroconverted by month 7. The GMT was 713 mIU/mL. Of these, 97% had seroprotective levels ( ≥ 10 mIU/mL).
Among infants enrolled (N = 381) to receive ENGERIX-B at 0, 1, and 2 months of age, 96% had seroprotective levels ( ≥ 10 mIU/mL) by month 4. The GMT among seroconverters (N = 311) (antibody titer ≥ 1 mIU/mL) was 210 mIU/mL. A subset of these children received a fourth dose of ENGERIX-B at 12 months of age. One month following this dose, seroconverters (N = 126) had a GMT of 2,941 mIU/mL.
Immunogenicity In Children And Adults
Persons 6 Months Through 10 Years of Age
In clinical trials, children (N = 242) 6 months through 10 years of age were given ENGERIX-B (10 mcg/0.5 mL) at 0, 1, and 6 months. One to 2 months after the third dose, the seroprotection rate was 98% and the GMT of seroconverters was 4,023 mIU/mL.
Persons 5 Through 16 Years of Age
In a separate clinical trial including both children and adolescents 5 through 16 years of age, ENGERIX-B (10 mcg/0.5 mL) was administered at 0, 1, and 6 months (N = 181) or 0, 12, and 24 months (N = 161). Immediately before the third dose of vaccine, seroprotection was achieved in 92.3% of subjects vaccinated on the 0-, 1-, and 6-month schedule and 88.8% of subjects on the 0-, 12-, and 24-month schedule (GMT: 117.9 mIU/mL versus 162.1 mIU/mL, respectively, P = 0.18). One month following the third dose, seroprotection was achieved in 99.5% of children vaccinated on the 0-, 1-, and 6-month schedule compared to 98.1% of those on the 0-, 12-, and 24-month schedule. GMTs were higher (P = 0.02) for children receiving vaccine on the 0-, 1-, and 6-month schedule compared to those on the 0-, 12-, and 24-month schedule (5,687.4 mIU/mL versus 3,158.7 mIU/mL, respectively).
Persons 11 Through 19 Years of Age
In clinical trials with healthy adolescent subjects 11 through 19 years of age, ENGERIX-B (10 mcg/0.5 mL) given at 0, 1, and 6 months produced a seroprotection rate of 97% at month 8 (N = 119) with a GMT of 1,989 mIU/mL (N = 118, 95% CI: 1,318, 3,020). Immunization with ENGERIX-B (20 mcg/1 mL) at 0, 1, and 6 months produced a seroprotection rate of 99% at month 8 (N = 122) with a GMT of 7,672 mIU/mL (N = 122, 95% CI: 5,248, 10,965).
Persons 16 Through 65 Years of Age
Clinical trials in healthy adult and adolescent subjects (16 through 65 years of age) have shown that following a course of 3 doses of ENGERIX-B (20 mcg/1 mL) given at 0, 1, and 6 months, the seroprotection (antibody titers ≥ 10 mIU/mL) rate for all individuals was 79% at month 6 (5 months after second dose) and 96% at month 7 (1 month after third dose); the GMT for seroconverters was 2,204 mIU/mL at month 7 (N = 110).
An alternate 3-dose schedule (20 mcg/1 mL given at 0, 1, and 2 months) designed for certain populations (e.g., individuals who have or might have been recently exposed to the virus and travelers to high-risk areas) was also evaluated. At month 3 (1 month after third dose), 99% of all individuals were seroprotected and remained protected through month 12. On the alternate schedule, a fourth dose of ENGERIX-B (20 mcg/1 mL) at 12 months produced a GMT of 9,163 mIU/mL at month 13 (1 month after fourth dose) (N = 373).
Persons 40 Years of Age and Older
Among subjects 40 years of age and older given ENGERIX-B (20 mcg/1 mL) at 0, 1, and 6 months, the seroprotection rate 1 month after the third dose was 88% and the GMT for seroconverters was 610 mIU/mL (N = 50). In adults older than 40 years of age, ENGERIX-B produced anti-HBsAg antibody titers that were lower than those in younger adults.
Interchangeability With Other Hepatitis B Vaccines
A controlled study (N = 48) demonstrated that completion of a course of immunization with 1 dose of ENGERIX-B (20 mcg/1 mL) at month 6 following 2 doses of RECOMBIVAX HB® (10 mcg) at months 0 and 1 produced a similar GMT (4,077 mIU/mL) to immunization with 3 doses of RECOMBIVAX HB (10 mcg) at months 0, 1, and 6 (GMT: 2,654 mIU/mL). Thus, ENGERIX-B can be used to complete a vaccination course initiated with RECOMBIVAX HB.8
6. André FE, Safary A. Clinical experience with a yeast-derived hepatitis B vaccine. In: Zuckerman AJ, ed. Viral Hepatitis and Liver Disease. New York, NY: Alan R Liss, Inc.; 1988:1025-1030.
7. Poovorawan Y, Sanpavat S, Pongpunlert W, et al. Protective efficacy of a recombinant DNA hepatitis B vaccine in neonates of HBe antigen-positive mothers. JAMA. 1989;261(22):3278- 3281.
8. Bush LM, Moonsammy GI, Boscia JA. Evaluation of initiating a hepatitis B vaccination schedule with one vaccine and completing it with another. Vaccine. 1991;9(11):807-809.
Last reviewed on RxList: 9/2/2014
This monograph has been modified to include the generic and brand name in many instances.
Additional Engerix-B Information
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