Merck bolstered its pneumococcal vaccine data on Monday, as the company looks to one-up Pfizer’s Prevnar 20 shot.
Merck said that its new conjugate vaccine, called V116, proved noninferior to its much older Pneumovax 23 vaccine for all 12 strains common to both vaccines. Pneumovax 23 is a 23-valent polysaccharide vaccine approved in 1982. More modern “conjugated” vaccines are designed to work better in younger children and potentially last longer.
An approval in the coming weeks would stoke Merck’s yearslong rivalry with Pfizer, whose Prevnar 20 was first approved in 2021, a mere month before Merck’s 15-valent Vaxneuvance. Prevnar 20 won a label expansion last April for children as young as 6 weeks, and executives revealed on Pfizer’s first-quarter 2024 earnings call that a fourth-generation pneumococcal candidate has entered the clinic.
Prevnar 20 held 96% of the adult market share in the US at the end of 2023, Pfizer’s chief US commercial officer Aamir Malik said in January during a call with analysts. Merck hopes that V116 could challenge that dominance. The FDA is expected to make a decision by June 17.
Last month, Merck released results suggesting its V116 offers broader protection than Prevnar 20 in older adults. Of 242 serotypes detected in more than 2,000 older adults hospitalized with community-acquired pneumonia, the data showed a quarter were covered by Merck’s V116, but not Vaxneuvance or Prevnar 20, according to the Merck-sponsored study. The samples were collected from patients 50 years and older at three hospitals in Tennessee and Georgia between 2018 and 2022.
The patients were not tested for serotype 15B, which is covered by Prevnar 20 but not by V116. A Merck spokesperson said the assays only detected serotypes in Merck’s vaccines, including 19 of 20 Prevnar serotypes. The spokesperson also noted that some surveillance systems are limited in their ability to distinguish between 15B and a closely related serotype called 15C, which is covered by V116.
Merck said its candidate was immunogenic for all 21 serotypes across multiple subgroups in separate studies, including adults who received a prior pneumococcal vaccine and those who did not.
The company touts V116 as the first pneumococcal vaccine “specifically designed for adults.” It covers 10 serotypes in common with Pfizer’s Prevnar 20, plus 11 unique serotypes, eight of which frequently cause disease in older adults and are not covered by any vaccines on the market.
“We also expect competition with V116 emerging that will make the adult market more competitive, but we see a lot of growth potential in the pediatric market,” Malik said on the January call, according to a transcript.
Editor’s Note: This story has been corrected to reflect that the newest V116 data compare the vaccine to Merck’s Pneumovax 23. The Prevnar 20 comparison data were published last month.