Merck’s pneumococcal vaccine for adults shows promise in Phase 3 trial

Merck on July 27 announced positive Phase 3 results for a new pneumococcal conjugate vaccine, which targets several varieties of bacteria that cause pneumococcal pneumonia.

If successful, it would be the first pneumococcal conjugate vaccine specifically designed for older adults – promising news, as older adults face greater risk of hospital-acquired infections like S. pneumonia.

According to a National Institutes of Health (NIH) report, “The overall rate of confirmed Streptococcus (S.) pneumoniae infection in the United States is 5.16 to 6.11 cases/100,000 in adults with the rate for those older than 65 years being 36.4/100,000 and infants younger than 1 year being 34.2/100,000.” S. pneumoniae is responsible for the contraction of meningitis, bacteremia, and pneumonia, as well as a variety of other types of infections.

Merck’s 21-valent pneumococcal conjugate vaccine (V116) in development targets several serotypes, or varieties of the bacteria, that are not covered by any vaccine. It is specifically designed for people 65 and over.

“According to pre-pandemic 2019 CDC (Centers for Disease Prevention and Control) data, the 21 serotypes covered by V116 are responsible for 85% of invasive pneumococcal disease in individuals 65 and older,” Merck explains. “V116 includes eight serotypes not currently covered by approved pneumococcal vaccines … which were responsible for approximately 30% of invasive pneumococcal disease in individuals 65 and older, based on pre-pandemic 2019 CDC data.”

If successful, V116 would be the first pneumococcal conjugate vaccine specifically designed for older adults. 

Merck’s V116 was shown to be comparably effective across the spectrum of patients, both vaccine-naïve and previously vaccinated individuals.

“Despite the availability of current pneumococcal conjugate vaccines, many adults remain vulnerable to pneumococcal disease, especially those who are older,” said Dr. Eliav Barr, SVP, Head of Global Clinical Development and Chief Medical Officer at Merck Research Laboratories. “These results support the potential for V116 to become an important new preventative option for adults, regardless of prior pneumococcal vaccination status.”

The next steps for Merck’s V116 vaccine

V116 is currently undergoing Phase 3 STRIDE-3 and STRIDE-6 clinical trials—both of which are randomized, double-blind, active comparator-controlled studies. So far, in STRIDE-3, there have been statistically significant immune responses to V116, especially in comparison to currently available pneumococcal vaccines across the spectrum of patients both previously vaccinated and vaccine-naïve. 

As Contagion Live reported, “Notably, V116 is also being examined in additional phase 3 clinical trials to assess safety and immunogenicity in special populations, including individuals with HIV (STRIDE-7; NCT05393037) and those at increased risk for pneumococcal disease, including individuals with diabetes, chronic liver disease, chronic obstructive pulmonary disease, mild or moderate persistent asthma, chronic heart disease, and/or chronic kidney disease (STRIDE-8; NCT05696080).”

So far, clinical trial populations have responded well overall. This new vaccine ups the competition for improved pneumococcal vaccines between Merck and Pfizer, whose PREVNAR 20® vaccine targeting S. pneumonia received Food and Drug Administration (FDA) approval for adults of all ages in 2021.

Merck and Pfizer are members of the Biotechnology Innovation Organization (BIO).

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