Pfizer has reported full analysis data from one of its Phase III trials of its 20-valent pneumococcal conjugate vaccine (20vPnC) candidate in adults not previously vaccinated against pneumococcal disease.

20vPnC includes 13 serotypes already included in pneumococcal 13-valent Conjugate Vaccine Prevnar (13), along with seven new serotypes that cause invasive pneumococcal disease (IPD) and are associated with high case-fatality rates, antibiotic resistance, and meningitis.

Results were presented as part of IDWeek’s virtual 2020 medical congress with data from Phase II proof-of-concept study in infants.

The vaccine candidate showed positive safety results and immune responses to 20 S pneumoniae serotypes in adults and infants.

Pfizer senior vice-president and Vaccine R&D head Kathrin Jansen said: “We are encouraged by the Phase III adult and Phase III pediatric data.

“The data suggest that 20vPnC would be anticipated to help protect against the serotypes covered by Prevnar 13, and also expand coverage to include seven additional pneumococcal serotypes causing potentially serious and life-threatening disease.”

The Phase III randomised, double-blind trial (NCT03760146) was conducted on 902 adults aged 18 or above who were previously given pneumococcal vaccination.

It analysed the safety profile of 20vPnC in all adults as the primary endpoint. The secondary endpoints were immune responses of 20vPnC in adults aged 18 to 59.

It also compared immune responses of participants aged 60 or above receiving 20vPnC to those in a control group receiving Prevnar 13 or a licensed pneumococcal polysaccharide vaccine (PPSV23).

Results showed that all 20 vaccine serotypes induced robust responses in all study groups.

In the Phase II multi-centre, randomised, active-controlled, double-blind trial with a two-arm parallel design, 460 infants aged 42 to 98 days were randomised to receive either 20vPnC or Prevnar 13 at two, four and six and 12 months of age.

The safety profile of a four-dose schedule of 20vPnC was consistent with 13vPnC.

Infants receiving either of the vaccines showed a similar percentage of local reactions, fever, and other systemic events.

This week, Merck reported that its 15-valent pneumococcal conjugate vaccine, V114, induced immune response in pneumococcal disease trials.