Introduction: Vaccination with formulations containing pneumococcal protein antigens such as pneumolysin toxoid (dPly) and histidine-triad protein D (PhtD) may extend serotype-related protection of pneumococcal conjugate vaccines (PCVs) against Streptococcus pneumoniae. Methods: This phase II, multi-center, observer-blind trial conducted in Europe (NCT01204658) assessed 2 investigational vaccines containing 10 serotype-specific polysaccharide conjugates of PHiD-CV and either 10 or 30 mu g of dPly and PhtD each.
Infants randomized 1:1:1:1 received 4 doses of PHiD-CV/dPly/PhtD-10, PHiD-CV/c1Ply/PhtD-30, PHiD-CV, or 13-valent PCV (PCV13), co-administered with DTPa-HBV-IPV/Flib, at ages 2, 3, 4 and 12-15 months. Occurrences of fever >40.0 degrees C following primary vaccination with PHiD-CV/dPly/PhtD vaccines compared to PHiD-CV (non-inferiority objective), dose superiority, safety and immunogenicity were assessed.
Conclusion: Both PHiD-CV/dPly/PhtD formulations co-administered with DTPa-HBV-IPV/Hib in infants were well-tolerated and immunogenic for dPly and PhtD antigens, while immune responses to serotype-specific, protein D and co-administered antigens did not appear altered in comparison to PHiD-CV grop.