Update: This article was updated June 18 to clarify the IPD and PCV20 serotypes covered by the new vaccine.
On June 17, the US Food and Drug Administration (FDA) approved CAPVAXIVE (V116, Merck) − a 21-valent pneumococcal conjugate vaccine − to prevent invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae and pneumonia caused by S. pneumoniae in adults age 18 years and older.
CAPVAXIVE is the first pneumococcal conjugate vaccine designed specifically for adults. In adults 65 years of age and older, CAPVAXIVE covers the serotypes responsible for approximately 85% of IPD cases, compared to approximately 51% covered by PCV20. Importantly, eight of these serotypes (15A, 15C, 16F, 23A, 23B, 24F, 31, and 35B) account for about 30% of adult disease but are not covered by any other FDA-approved pneumococcal vaccine.
The FDA granted V116 a Biologics License Application (BLA) Priority Review in December 2023, which is a designation given to drugs and vaccines that may provide a significant improvement in the safety or effectiveness of the treatment or prevention of a serious condition.
Rationale for a New Vaccine
Pneumococcal disease broadly encompasses infections caused by Streptococcus pneumoniae bacteria, of which more than 100 serotypes exist. These pneumococcal bacteria can affect adults differently than children, placing them at risk for both non-invasive pneumonias confined to the lungs and invasive pneumococcal illnesses including bacteremia, bacteremic pneumonia, and meningitis. Individuals aged 50 years and older are at the highest risk of mortality from IPD, especially those with certain chronic or immunocompromising health conditions, such as heart disease, lung disease, and liver disease.
Preventing pneumococcal disease in individuals living with human immunodeficiency virus (HIV) is also critically important due to their increased susceptibility to infections caused by S. pneumoniae. HIV compromises the immune system, making these individuals more vulnerable to IPD and severe complications. Additionally, the higher incidence and severity of these infections in individuals who are HIV-positive can lead to increased morbidity and mortality.
Evidence for CAPVAXIVE to Date
The FDA based its decision on the results from the STRIDE Phase 3 clinical trial program, which included multiple studies: STRIDE-3 (pneumococcal vaccine-naïve adults), STRIDE-4 (pneumococcal vaccine-naïve adults 18 to 49 years old), STRIDE-5 (concomitant administration with influenza vaccine), STRIDE-6 (pneumococcal vaccine-experienced adults), STRIDE-7 (adults living with HIV), STRIDE-8 (adults with increased risk for pneumococcal disease), STRIDE-9 (vaccine-naïve Japanese older adults), and STRIDE-10 (pneumococcal vaccine-naïve adults aged 50 years and older).
Key findings from the STRIDE clinical trials include:
Pneumococcal vaccine-naïve adults aged 50 years and older (STRIDE-3 subgroup): CAPVAXIVE was immunogenic for all 21 serotypes across all age groups (50 to 64, 65 to 74, and 75 to 84 years)
Pneumococcal vaccine-experienced adults aged 50 years and older (STRIDE-6): Immune responses to CAPVAXIVE were comparable for PCV15 (pneumococcal 15-valent conjugate vaccine) or PPSV23 (pneumococcal vaccine, polyvalent [23-valent]) for shared serotypes. CAPVAXIVE induced higher immune responses for serotypes unique to this vaccine, irrespective of prior pneumococcal vaccine received or time since previous vaccination.
Adults living with HIV aged 18 years and older (STRIDE-7): CAPVAXIVE produced comparable immune responses to PCV15 and PPSV23 for all 13 shared serotypes and higher immune responses for the vaccine’s eight unique serotypes.
Across all STRIDE studies, CAPVAXIVE's safety profile was comparable to the studied comparators, including PCV20, PCV15, and PPSV23.
CAPVAXIVE is designed to prevent pneumococcal pneumonia and IPD in adults after only one dose; no booster doses are currently recommended.
The CDC Advisory Committee on Immunization Practices is expected to meet in late June to discuss and make recommendations regarding CAPVAXIVE's use in adults.
