Pfizer’s experimental PF-07872412 generated immune responses against all 25 targeted pneumococcal strains in a Phase 2 infant trial, with particularly strong results against serotype 3, as the vaccine moves into late-stage testing.
Pfizer has reported encouraging Phase 2 results for its experimental 25-strain infant pneumococcal vaccine, saying the shot produced immune responses against all targeted strains and was generally well tolerated in healthy full-term babies. The company presented the data on 24 October, with the study designed primarily to assess safety rather than to prove that the vaccine prevents illness.
The candidate, PF-07872412, adds five strains to Prevnar 20, Pfizer’s existing 20-valent pneumococcal vaccine. In the randomised study, 401 infants received either the experimental vaccine or Prevnar 20 in a four-dose schedule. Pfizer said it found no related serious adverse events, while local and systemic reactions were mostly mild to moderate. Fever after the first dose was reported in 24.8% of children given the candidate and 23.1% of those who received the comparator, while injection-site pain was recorded in 63.4% and 53.8% respectively.
Pfizer said the immune response was especially strong against serotype 3, with antibody levels about 15 times higher than Prevnar 20 a month after the fourth dose. After the third dose, the comparison was 8.8 times higher. The company also said functional antibody responses were seen against every targeted strain after the final dose. However, the presentation did not include confidence intervals or formal non-inferiority margins, and the data showed immune responses rather than actual reductions in infection.
The company has already moved into a broader late-stage programme. Pfizer said three Phase 3 studies are under way, involving as many as 6,830 participants, to assess safety and efficacy more fully. The manufacturer also said a consistency study for the production lot had finished enrolment. Annaliesa Anderson, Pfizer’s chief vaccines officer, said in the company’s release that, “If successful, it could help provide children with the broadest protection against invasive pneumococcal disease to date.”
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
