Immunogenicity and safety study of a new DTaP–IPV–Hep B–PRP-T combined vaccine compared to a licensed DTaP–IPV–Hep B//PRP-T comparator, both concomitantly administered with a 7-valent pneumococcal conjugate vaccine at 2, 4, and 6 months of age in Thai infants

OBJECTIVE: To assess a new, fully-liquid, hexavalent DTaP–IPV–Hep B–PRP-T vaccine (diphtheria toxoid (D), tetanus toxoid (T), acellular pertussis (aP), inactivated poliovirus (IPV), hepatitis B (Hep B), and Haemophilus influenzae type b polysaccharide conjugated to tetanus protein (PRP-T) antigens) compared to a licensed DTaP–IPV–Hep B//PRP-T vaccine following primary series co-administration with a 7-valent pneumococcal conjugate vaccine (PCV7). METHODS: This was a randomized, phase III, observer-blind study in Thai infants (N=412), who received DTaP–IPV–Hep B–PRP-T or DTaP–IPV–Hep B//PRP-T at 2, 4, and 6 months of age, co-administered with PCV7. All received Hep B at birth. Non-inferiority for Hep B ≥10 mIU/ml and PRP ≥0.15μg/ml was analyzed (DTaP–IPV–Hep B–PRP-T relative to DTaP–IPV–Hep B//PRP-T) at 1 month post-primary. Seroprotection/seroconversion and geometric mean titers (GMTs) were analyzed descriptively for all hexavalent components. Safety was evaluated from parental reports. RESULTS: Anti-Hep B and anti-PRP antibody seroprotection rates were high for DTaP–IPV–Hep B–PRP-T (n=189) and DTaP–IPV–Hep B//PRP-T (n=190), and non-inferiority was demonstrated. Anti-D and anti-T ≥0.01 IU/ml, anti-polio types 1, 2, and 3 ≥8 (1/dil), and anti-PT and anti-FHA seroconversion were high and similar in each group. For DTaP–IPV–Hep B–PRP-T and DTaP–IPV–Hep B//PRP-T, anti-Hep B ≥100mIU/ml was 98.4% and 99.5% (GMTs 2477 and 2442mIU/ml), respectively; anti-PRP ≥1.0μg/ml was 85.2% and 71.1% (GMTs 5.07 and 2.41μg/ml), respectively. Safety profiles were comparable. There were no vaccine-related serious adverse events. CONCLUSIONS: Following co-administration with PCV7 the investigational DTaP–IPV–Hep B–PRP-T vaccine was safe and immunogenic. Non-inferiority to DTaP–IPV–Hep B//PRP-T was shown for Hep B and PRP.