ENGERIX-B Rx

Efficacy in Neonates

• Protective efficacy with Engerix-B was demonstrated in a clinical trial in neonates at high risk of hepatitis B infection.
• 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%.

Immunogenicity in Neonates

• In clinical studies, neonates were given Engerix-B (10 mcg/0.5 mL) at age 0, 1, and 6 months or at age 0, 1, and 2 months. The immune response to vaccination was evaluated in sera obtained 1 month after the third dose of Engerix-B.
• Among infants given Engerix-B at age 0, 1, and 6 months, 100% of evaluable subjects (n=52) seroconverted by Month 7. The geometric mean antibody titer (GMT) was 713 mIU/mL. Of these, 97% had seroprotective levels (≥10 mIU/mL).
• Among infants enrolled (n=381) to receive Engerix-B at age 0, 1, and 2 months, 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 age 12 months. One month following this dose, seroconverters (n=126) had a GMT of 2941 mIU/mL.

Immunogenicity in Children and Adults

Persons Aged 6 Months through 10 Years

• In clinical trials, children (N=242) aged 6 months through 10 years 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 4023 mIU/mL.

Persons Aged 5 through 16 Years

• In a separate clinical trial including both children and adolescents aged 5 through 16 years, 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 patients vaccinated on the 0-, 1-, and 6-month schedule and 88.8% of patients on the 0-, 12-, and 24-month schedule (GMT: 118 mIU/mL vs 162 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 with 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 with those on the 0-, 12-, and 24-month schedule (5687 mIU/mL vs 3159 mIU/mL, respectively).

Persons Aged 11 through 19 Years

• In clinical trials with healthy adolescent patients (aged 11 through 19 years), 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 1989 mIU/mL (n=118; 95% CI, 1318-3020). 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 7672 mIU/mL (n=122; 95% CI, 5248-10965).

Persons Aged 16 through 65 Years

• Clinical trials in healthy adult and adolescent patients (aged 16 through 65 years) 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 2204 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 (eg, 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 9163 mIU/mL at Month 13 (1 month after fourth dose) (n=373).

Persons Aged 40 Years and Older

• Among patients aged 40 years 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 aged older than 40 years, Engerix-B produced anti-HBsAg antibody titers that were lower than those in younger adults.