Regulatory Decision Summary for Boostrix

Study DTPA-047 showed higher pertussis antibody concentrations at delivery in the cord blood of infants born to mothers vaccinated with Boostrix versus placebo during the pregnancy. The levels of antibodies against the pertussis antigens PT, FHA and PRN were respectively 8, 16 and 21 times, higher in the cord blood of infants born to vaccinated mothers versus unvaccinated mothers. The results of study DTPA-047 support the maternal immunization with Boostrix to provide protection against pertussis in early infancy.

Two follow-up studies, DTPA-048 and DTPA-049, evaluated the immunogenicity and safety of Infanrix hexa and Prevnar 13 given in a primary vaccination schedule and a booster dose to more than 500 infants born to mothers who participated in study DTPA-047.

One month post primary vaccination and one month post booster dose of Infanrix hexa and Prevnar 13:

• The percentages of infants/toddlers who achieved seroprotection were comparable between infants/toddlers born to vaccinated mothers and unvaccinated mothers, in terms of anti-D, anti-T, anti-HBs, anti-polio, anti-PRP and anti-pneumococcal antigens.
• The antibody levels of anti-PT, anti-FHA, and anti-PRN were lower in the infants born to mothers who were vaccinated with Boostrix during pregnancy. However, 92.1% to 98.1% of infants and toddlers born to vaccinated mothers showed a booster response (post-booster antibody concentration ≥2 times the pre-booster antibody concentration) against pertussis antigens. In addition, the epidemiology data from England and US confirmed the benefit of maternal immunization of DTaP vaccine and did not suggest any clinical relevance of observed immune interference.

Boostrix was generally well tolerated in the pregnant women. The percentages of pregnant women who reported pregnancy/neonate-related adverse events were low and generally comparable between two groups.

The primary vaccination and the booster dose of Infanrix hexa and Prevnar 13 were generally well tolerated in infants of both groups.

The congenital anomalies which were reported from delivered infants in study DTPA-047 up to the end of the booster study DTPA-049 were provided. The percentages of infants/toddlers with at least one congenital anomaly were generally comparable between the infants/toddlers born to vaccinated mothers and the infants/toddlers born to unvaccinated mothers. The reported congenital anomaly were consistent with the background incidence.

Based on the clinical evaluation of efficacy and safety data submitted, the overall benefit/risk profile of Boostrix is considered favourable passive protection against pertussis in early infancy following maternal immunization during pregnancy.