Pfizer Reports Positive Study Results for Pneumococcal Conjugate Vaccine in Infants in the EU

Pfizer announced positive topline results from its pivotal European Union phase 3 study (NCT04546425) in infants, evaluating the 20-valent pneumococcal conjugate vaccine candidate (20vPnC) for the prevention of acute otitis media, invasive pneumococcal disease (IPD), and pneumonia.

There were 3 coprimary outcomes in the study, which were associated with immunogenicity responses 1 month after the second and third doses of the 3-dose series given at 2, 4 and 11 to 12 months of age for 20vPnC, compared with the pneumococcal conjugate vaccine Prevenar 13 Pfizer.

One of the non-inferiority (NI) coprimary objectives was immunoglobulin G (IgG) geometric mean concentrations (GMCs) 1 month after dose 3 between 11 and 12 months of age. Investigators found that 19 of the 20 serotypes met the NI criteria.

For the NI coprimary objective of IgG GMCs 1 month after the second dose, investigators found that 16 of the 20 serotypes met the NI.

Furthermore, for the third NI coprimary objective of the percentage of individuals with predefined serotype-specific IgG concentrations 1 month after the second dose, 9 of the 20 serotypes met the criteria.

Investigators also found that all 20 serotypes had increased booster responses from after the second dose to after the third dose, which show that the vaccine candidate is indicative of immunological memory and long-term protection.

Additionally, all 20 serotypes also showed strong functional antibody responses, as measured by the opsonophagocytic assay after the second and third doses, which is similar to Prevenar and Prevenar 13.

Data from 20vPnC was consistent with prior clinical experience with both Prevenar and Prevenar 13 after the second and third infant doses, investigators said.

Both doses demonstrated effectiveness in a 3-dose schedule against the serotypes contained in the vaccine in post-licensure studies.

If approved, the vaccine candidate is likely to protect against all 20 vaccine serotypes in a 3-dose schedule, investigators said.

The safety profile of 20vPnC was similar to Prevenar 13 in this schedule, and concomitant use with common pediatric vaccines was also supported.

Pfizer plans to file these data by the end of the year with the European Medicines Agency. The company will also seek to present and publish data from this clinical trial at a future date once immunogenicity and safety results are fully analyzed.

The company reported that the positive data mark the conclusion of pivotal topline results for the 20vPnC pediatric program.

The 20vPnC pediatric vaccine candidate includes the 13 serotypes in Prevenar 13 but also adds 7 new serotypes that are causes of IPD and are associated with antibiotic resistance, high case-fatality rates, and/or meningitis.

These 20 serotypes are responsible for the majority of circulating pneumococcal disease in the European Union and globally, according to a statement by Pfizer.

In February 2022, the European Commission Decision was adopted for the vaccine for the prevention of invasive disease and pneumonia caused by the 20 serotypes in the vaccine for adults.

Reference

Pfizer announces positive top-line results from phase 3 study in 20-valent pneumococcal conjugate vaccine in infants in the European Union. News release. Pfizer. September 19, 2022. Accessed September 19, 2022. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-announces-positive-top-line-results-phase-3-study-0