INFANRIX Rx

Diphtheria and Tetanus

• The efficacy of diphtheria and tetanus toxoid used in Infanrix was based on immunogenicity studies.

• A VERO cell toxin-neutralizing test confirmed the ability of infant sera (N =45), obtained 1 month after a 3-dose primary series, to neutralize diphtheria toxin. Levels of diphtheria antitoxin ≥0.01 IU/mL were achieved in 100% of the sera tested.

• An in vivo mouse neutralization assay confirmed the ability of infant sera (N =45), obtained 1 month after a 3-dose primary series, to neutralize tetanus toxin. Levels of tetanus antitoxin ≥0.01 IU/mL were achieved in 100% of the sera tested.

Pertussis

• 2 clinical studies evaluated the efficacy of Infantrix as a 3-dose primary series.

• In a double-blind, randomized, active Diphtheria and Tetanus Toxoids (DT)-controlled trial conducted in Italy, the absolute protective efficacy of Infanrix was assessed when administered at 2, 4, and 6 months of age. Infants were randomly assigned to receive Infanrix (n=4,481) or DT vaccines (n=1,470). The mean length of follow-up was 17 months beginning 30 days after the third dose of the vaccine.

• The absolute protective efficacy of Infanrix against WHO-defined typical pertussis (21 days or more of paroxysmal cough with infection confirmed by culture and/or serologic testing) was 84% (95% CI, 76-89) after 3 doses.

• When the definition of pertussis was expanded to include clinically milder disease with respect to type and duration of cough, with infection confirmed by culture and/or serologic testing, the efficacy of Infanrix was 71% (95% CI, 60-78) against more than 7 days of any cough and 73% (95% CI, 63-80) against at least 14 days of any cough.

• In a follow-up period from 24 months to a mean age of 33 months, the efficacy of Infanrix against WHO-defined pertussis was 78% (95% CI, 62-87).

• In a third follow-up period in children aged 3 to 6 years, the efficacy of Infanrix against WHO-defined pertussis was 86% (95% CI, 79-91).

• In a prospective efficacy trial conducted in Germany employing a household contact study design, 3 doses of Infanrix was administered at 3, 4, and 5 months of age in more than 22,000 children. Infants who did not participate in the study could have received a DTwP or DT vaccine. Calculation of vaccine efficacy was based on attack rates of pertussis in household contacts.

• Among 173 contacts who did not receive a pertussis vaccine, 96 developed WHO-defined pertussis vs 7 of 112 contacts vaccinated with Infanrix. The protective efficacy of Infanrix was 89% (95% CI, 77-95).

• When the definition of pertussis was expanded to include clinically milder disease with infection confirmed by culture and/or serologic testing, the efficacy of Infanrix was 67% (95% CI, 52-78) against at least 7 days of any cough and 81% (95% CI, 68-89) against at least 7 days of paroxysmal cough. The corresponding efficacy of Infanrix was 73% (95% CI, 59-82) against at least 14 days of any cough and 84% (95% CI, 71-91) against at least 14 days of paroxysmal cough.

Pertussis Immune Response to Infanrix Administered as a 3-Dose Primary Series

• 3 clinical studies (1 Italian efficacy study; 1 US study; and 1 German study) evaluated the immune responses to each of the 3 pertussis antigens contained in Infanrix in sera obtained 1 month after the third dose of vaccine. 

• One month after the third dose, the response rates to each pertussis antigen were similar in all 3 studies.

Immune Response to Concomitantly Administered Vaccines

• A US study evaluated the concomitant use of Infanrix with Hib conjugate vaccine at 2, 4, and 6 months of age. 

• 90% of 72 infants had anti-PRP ≥1.0 mcg/mL one month after the third dose of Hib conjugate vaccine.

• A US study evaluated the concomitant use of Infanrix with Engerix-B, IPV, PCV7, and Hib conjugate vaccines at 2, 4, and 6 months of age.

• 99.2% of 121 patients who did not receive a birth dose of hepatitis B vaccine achieved anti-HBsAg ≥10 mIU/mL following the third dose of Engerix-B.

• 100% of 153 patients achieved anti-poliovirus 1, 2, and 3, ≥1:8 following the third dose of IPV.

• 91.8% to 99.4% of patients achieved anti-pneumococcal polysaccharide ≥0.3 mcg/mL for serotypes 4, 9V, 14, 18C, 19F, and 23F, and 73.0% had a level ≥0.3 mcg/mL for serotype 6B after the third dose of PCV7 vaccine.