Immunogenicity and safety of an investigational hexavalent diphtheria-tetanus-acellular pertussis-inactivated poliovirus-hepatitis B-Haemophilus influenzae B conjugate combined vaccine in healthy 2-, 4-, and 6-month-old Argentinean infants.

Background and Aims: Assessment of a new, fully liquid, investigational hexavalent DTaP-IPV-Hep B-PRP-T vaccine (Hexaxim, Sanofi Pasteur), containing the same active ingredients as Pentaxim (DTaP-IPV//PRT-T) and 10 μg Hansenula polymorpha-derived recombinant hepatitis B (Hep B) surface antigen, Sanofi Pasteur, in Argentinean infants.
Methods: Infants born to Hep B surface antigen seronegative mothers were randomized to receive the DTaP-IPV-Hep B-PRP-T vaccine or Pentaxim and Engerix B Pediatrico (Hep B monovalent) vaccines at 2, 4, 6 months of age. Antibody titers were measured before and 1 month after 3-month primary vaccination. Noninferiority analyses were performed on seroprotection/seroconversion rates. Safety was evaluated descriptively up to 1 month after primary vaccination.
Results: A total of 624 participants were enrolled, 312 participants were randomized to each group, and 604 participants completed the trial. The DTaP-IPV-Hep B-PRP-T vaccine was demonstrated as noninferior to the Pentaxim and Hep B monovalent vaccines with seroprotection/seroconversion rates 1 month postdose 3 for each valence. The anti-Hep B geometric mean titer 1-month postdose 3 for the investigational DTaP-IPV-Hep B-PRP-T primary series was similar to the monovalent Hep B control. The overall incidence of adverse events was similar among the 2 groups.
Conclusions: The new, fully liquid, investigational DTaP-IPV-Hep B-PRP-T vaccine (Hexaxim) is highly immunogenic and safe when compared with licensed comparators, warranting further development.