Merck’s latest vaccine candidate, V116, has demonstrated comparable efficacy and safety to Pfizer’s Prevnar 20, as revealed by Phase 3 trial results released on Tuesday. The STRIDE-3 trial indicated that V116 elicited non-inferior immune responses to Prevnar 20, which recently received FDA approval for use in children and infants in April.
V116 stands out for its superior immune response in 10 of the 11 serotypes it targets, as measured by serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs). These serotypes are responsible for approximately 83% of pneumococcal disease cases in older adults, a demographic particularly vulnerable to the disease, according to the Centers for Disease Control and Prevention (CDC). Pneumococcal disease encompasses a range of illnesses caused by Streptococcus pneumoniae bacteria, including sinus infections, pneumonia, and blood infections, which can lead to severe complications such as meningitis and bacteremia in the elderly or immunocompromised.
Merck’s V116 is poised to become the first pneumococcal vaccine specifically designed for the adult population. “These results provide strong evidence to support the immunogenicity of V116 compared to the standard of care in the prevention of invasive pneumococcal disease and pneumococcal pneumonia in adults,” said Dr. Eliav Barr, SVP, head of global clinical development, and chief medical officer at Merck Research Laboratories.
The emergence of V116 as a potential rival to Prevnar 20, which currently dominates the pneumococcal vaccine market, signifies a shift in the competitive landscape. Other pharmaceutical companies, such as GSK, are also vying for market share. GSK’s acquisition of Affinivax for $2.1 billion in 2022 granted them access to Affinivax’s 24-valent pneumococcal vaccine, AFX3772. Additionally, Vaxcyte reported encouraging Phase 2 study results for its 24-valent pneumococcal vaccine, VAX-24, in April.
The positive STRIDE-3 trial data for V116 comes in the wake of the FDA’s rejection of Merck’s chronic cough drug, gefapixant, which an FDA committee voted 12-1 against due to its marginal clinical benefit.
Despite this setback, Merck is optimistic about V116’s prospects and plans to seek regulatory approval, although the company has not specified a timeline. The STRIDE-3 data will be shared with global health authorities. Dr. Sady Alpizar, principal investigator of STRIDE-3, commented on the potential of V116 to prevent invasive pneumococcal disease in at-risk populations.
