20vPnC Pneumococcal Conjugate Vaccine Candidate Shows Promise in Phase 3 Study

Pfizer Inc., has announced top-line results from a phase 3 study which evaluated the immunogenicity and safety of a 20-valent pneumococcal conjugate vaccine candidate (20vPnC).

The study assessed 20vPnC in adults 18 years of age and older who were not previously vaccinated against pneumococcal disease.

The phase 3 randomized, double-blind trial enrolled 3880 participants. Overall, the study investigators found that safety objectives were met, and safety and tolerability were similar to licensed pneumococcal vaccines.

All serotypes in common with the licensed Prevnar 13 pneumococcal 13-valent conjugate vaccine met primary immunogenicity objectives of non-inferiority in adults 60 years of age and older at 1 month after vaccination.

Out of the 7 additional serotypes, when compared to the licensed PPSV23 pneumococcal polysaccharide vaccine, 6 met noninferiority objectives in adults 60 years of age and older.

“…1 of the new 7 serotypes missed noninferiority criteria by a small margin,” according to the press release

All 20 serotypes met noninferiority for secondary immunogenicity objectives comparing adults 18 to 59 with adults 60 to 64 years of age.

“The results from this pivotal study provide evidence that the 20vPnC vaccine is expected to have a comparable safety profile and likely be as effective as Prevnar 13 in helping prevent invasive pneumococcal disease and pneumonia due to the 13 serotypes in Prevnar 13, and also effective against disease due to the seven additional pneumococcal serotypes in adults 18 years of age or older,” Kathrin Jansen, PhD, head of vaccine research & development, at Pfizer, said in the statement.

In addition to the 13 serotypes included in Prevnar 13, 20vPnC includes 7 new serotypes which are associated with invasive pneumococcal disease cases with high fatality rates, antibiotic resistance, and/or meningitis. The 20 serotypes in 20vPnC are responsible for most circulating pneumococcal disease globally.

“This is particularly important for the 7 additional pneumococcal serotypes due to the burden of pneumonia caused by the new serotypes and the lack of herd protection for adults since the current pediatric vaccine does not protect against the seven additional strains,” Luis Jodar, PhD, chief medical and scientific affairs officer for Pfizer Vaccines said in the statement.

The 20vPnC vaccine candidate was granted Breakthrough Therapy Designation by the US Food and Drug Administration (FDA) in 2018.

The vaccine candidate was also granted Fast Track designations for adults and pediatric populations in 2017.

There are 2 additional trials of 20vPnC completed, with results expected within the coming months.

Of the additional trials, 1 was a randomized double-blind trial meant to provide additional safety data and evaluate 3 different lots of 20vPnC in adults between 18 through 49 years of age without a history of pneumococcal vaccination.

The other additional study was an open label, randomized trial providing data on the safety and immune response of 20vPnC in about 875 adults 65 years of age and older who have a prior history of pneumococcal vaccination.

Pneumococcal and other vaccines are linked to considerable declines in childhood mortality from lower-respiratory infections over the past 3 decades.

In general, pneumococcal vaccines have led to reduction in not only pneumonia, but also sepsis and bacteremia in immunized populations. However, there are concerns that the current vaccine strategy does not adequately address meningitis, making expansion of the vaccine arsenal an important goal.