Merck’s 21-valent pneumococcal vaccine was approved by the FDA on Monday, bringing a new competitor to market for Pfizer’s 20-valent product.
Merck’s vaccine, called Capvaxive, was specifically designed for adults. The strains covered by Capvaxive were responsible for 84% of invasive pneumococcal disease in patients 50 years and older between 2018 and 2021, Merck said. That includes 10 strains in common with Pfizer’s Prevnar 20, plus 11 unique strains, eight of which aren’t covered by any other vaccines on the market.
“These serotypes were selected not only because of their frequency but because of their propensity to cause invasiveness and severe disease,” Merck’s Capvaxive investigator Heather Platt told Endpoints News ahead of the decision.
The vaccine is approved for both the prevention of invasive pneumococcal disease and pneumococcal pneumonia. The pneumonia indication was approved under the FDA’s accelerated approval pathway.
The CDC’s Advisory Committee on Immunization Practices, which makes recommendations on how and when to use vaccines, will discuss Capvaxive in a June 27 meeting. A Merck spokesperson said the company expects the vaccine will be available for use by late summer.
“We are very confident about supply. We will absolutely be ready to take advantage even before the flu season hits,” Platt said.
In April, Merck unveiled new data showing Capvaxive was non-inferior to its much older Pneumovax 23 vaccine for all 12 strains common to both vaccines. Pneumovax 23 is a 23-valent polysaccharide vaccine, while more modern “conjugated” vaccines like Capvaxive are designed to be more durable and longer-lasting.
The vaccine will compete with Prevnar 20, which dominates the adult market and was approved a month before Merck’s 15-valent Vaxneuvance in 2021. While Merck focuses on adults, Pfizer has been expanding into the pediatric population. Prevnar 20 was approved in April 2023 to prevent pneumococcal disease in children 6 weeks to 17 years. Vaxneuvance is also approved in people 6 weeks and older but doesn’t cover as many strains.
Pfizer executives said on an April call with analysts that a fourth-generation pneumococcal candidate had recently entered the clinic, according to an AlphaSense transcript.