Five months ago, Merck & Co. revealed data that indicate its next-generation pneumococcal vaccine offers more protection for older adults than Pfizer’s market dominator Prevnar 20. Now, the company is comparing the investigational shot to its old warhorse, Pneumovax 23 (PPSV23).
In the STRIDE-10 study, Merck’s V116—which is a 21-valent conjugate vaccine designed for adults—stacked up favorably against PPSV23, a 23-valent polysaccharide vaccine that was approved back in 1983. Merck presented the results Monday at the 34th European Society of Clinical Microbiology and Infectious Diseases in Barcelona, Spain.
In the phase 3 study, which included 1,484 participants age 50 and older who had never had a pneumococcal vaccine, V116 produced noninferior immune responses compared to those for Pneumovax 23 after 30 days in the 12 serotypes the vaccines share.
For the nine strains unique to V116, immune responses were superior in all the serotypes by one standard of measure and in eight of the serotypes when another assessment tool was used. The shots also had comparable safety profiles.
“Even with the availability of current pneumococcal conjugate vaccines for adults, gaps in serotype coverage for invasive pneumococcal disease persist,” Eliav Barr, M.D., Merck’s head of global clinical development and the chief medical officer of its R&D unit, said in a release. “These data add to the evidence supporting the potential for V116 to become an important new preventative option for adults, with results showing V116 elicited immune responses to the serotypes responsible for the majority of adult invasive pneumococcal disease.”
Eight of the serotypes found in V116 are not found in any pneumococcal vaccine on the market. The targeted serotypes of V116 account for 83% of cases of invasive pneumococcal disease among individuals aged 65 and over in the U.S.
In November 2023 at the World Vaccine Congress West Coast, Merck presented data from the phase 3 STRIDE-3 trial for adults 50 and older that showed V116 matched Prevnar 20 in shared serotypes and performed better in 10 of its 11 unique strains.
The trials have set up V116 for a June 17 decision date with the FDA. The European Medicines Agency is also reviewing V116.
With an approval, Merck has a chance to grab a larger share of the pneumococcal vaccine market. In 2023, the company scored $665 million in sales of its 15-valent pneumococcal shot Vaxneuvance (V114), which was approved in 2021. Meanwhile, the growth (PDF) of Pfizer’s Prevnar family of pneumococcal vaccines in 2023 slowed to 2%, reaching $6.4 billion.
“We cover 83% of the serotypes-causing disease in adults. That's 30% higher than PCV20, so it’s significant,” Merck CEO Rob Davis said during the company’s quarterly earnings call last week. “And that was how it was specifically designed, targeting those serotypes which are most prevalent in adult disease. As a result of that, we continue to believe the value proposition of V116 is very compelling.”
Pneumococcal disease is caused by bacteria that can invade the lungs, causing pneumonia; the bloodstream, causing sepsis; or the lining of the brain, causing meningitis. Anyone can catch the disease, which is spread by person to person contact through coughing and sneezing. The most vulnerable are children younger than 2 years of age, adults 65 and older and others with chronic health conditions.