Pneumococcal 21-Valent Conjugate Vaccine Generates Positive Response in Adults at Increased Risk of Disease

Key Takeaways

PCV21 demonstrated robust immunogenicity for all 21 strains, comparable to PCV15 and PPSV23, in high-risk adults aged 18-64.
The FDA approved PCV21 for adults 18 and older, with CDC recommendations for high-risk groups aged 19-64 and those 65+.
Safety data showed fewer adverse events with PCV21 compared to PCV15 and PPSV23, including injection site and systemic reactions.
A modeling study indicated PCV21's superior long-term health impact over PCV20, reducing pneumococcal disease cases by 33.9% over a decade.

Data presented at IDWeek also showed greater disease-prevention effects in the community with PCV21 compared with prior pneumococcal vaccines.

New results from STRIDE-8 (NCT05696080), a phase 3 trial evaluating the pneumococcal 21-valent conjugate vaccine (PCV21; Capvaxie), were presented at IDWeek 2024, demonstrating the efficacy of the vaccine in adults 18 to 64 years of age with heightened risk of pneumococcal disease who had not previously received a pneumococcal vaccine.^1,2

The positive results, announced last week in a news release from Merck, further highlight the robust immunogenic properties of the vaccine. In the trial, PCV21 was immunogenic for all 21 strains included at day 30. Further, the immune responses were comparable to those generated by the combination of pneumococcal 15-valent conjugate vaccine (PCV15) and pneumococcal 23-valent polysaccharide vaccine (PPSV23).¹

Vial with pneumococcal disease vaccine and syringe for injection.

Pneumococcal 21-valent conjugate vaccine has already been approved by the FDA and recommended by the CDC for disease prevention in adults. | Image Credit: © Alexey Novikov | stock.adobe.com

“Adults with chronic medical conditions, such as kidney disease or diabetes, are particularly vulnerable to invasive pneumococcal disease, which may increase their risk of severe illness,” Walter Orenstein, MD, member of Merck’s Scientific Advisory Committee, noted in the news release. “These data further demonstrate that the broad serotype coverage Capvaxie provides can help prevent invasive disease among vulnerable adults.”¹

In June, the FDA granted regulatory approval to the vaccine for the prevention of pneumococcal disease and pneumonia in those 18 years and older. Serotypes covered in the vaccination include 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15B, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B for the invasive disease indication.³

Following its approval in the United States, the CDC’s Advisory Committee on Immunization Practices (ACIP) voted unanimously to recommend the vaccine for appropriate adults 65 years and older who had not previously received a vaccine or whose vaccination history is unknown. In addition, they recommended that adults 19 to 64 years of age with certain risk factors receive the vaccine.⁴

Researchers in the STRIDE-8 trial also garnered important safety data, with a lower proportion of patients that received PCV21 experiencing adverse events (AEs) compared with the patients that received PCV15 and PPSV23. These included injection site, systemic, and vaccine-related AEs.¹

About the Trial

Trial Name: Safety and Immunogenicity of V116 in Adults With Increased Risk for Pneumococcal Disease (V116-008) (STRIDE-8)

ClinicalTrials.gov ID: NCT05696080

Sponsor: Merck Sharp & Dohme LLC

Completion Date: February 16, 2024

During the IDWeek presentation, investigators also showcased important results from a targeted literature review of the clinical and economic burden of pneumococcal disease in adults throughout the country. According to the review, Black adults and adults in rural areas with low levels of education face lower rates of pneumococcal vaccination and increased disease burden.¹

Results from a modeling study were also highlighted, in which PCV21 was compared with pneumococcal 20-valent conjugate vaccine (PCV20) regarding their health impact in US adults. According to the data, the use of PCV21 led to fewer overall cases of pneumococcal disease than PCV20 after a decade, with a 33.9% reduction across all ages compared with a 28.9% reduction for PCV20. This reduction equates to 14,000 fewer cases of pneumococcal disease.¹

“The data presented during IDWeek build on the robust clinical profile of CAPVAXIVE and illustrate the importance of improving equitable access for those at high risk for invasive pneumococcal disease,” Macaya Douoguih, MD, therapeutic area head of vaccines clinical research at Merck, said in the news release.¹

REFERENCES

1. Merck. Merck’s Capvaxie (pneumococcal 21-valent conjugate vaccine) demonstrates positive immune responses in adults with increased risk for pneumococcal disease. News Release. Released October 16, 2024. Accessed October 16, 2024. https://www.merck.com/news/mercks-capvaxive-pneumococcal-21-valent-conjugate-vaccine-demonstrates-positive-immune-responses-in-adults-with-increased-risk-for-pneumococcal-disease/

2. ClinicalTrials.gov. Safety and immunogenicity of V116 in adults with increased risk for pneumococcal disease (V116-008) (STRIDE-8). National Library of Medicine. Last Updated February 28, 2024. Accessed October 16, 2024. https://clinicaltrials.gov/study/NCT05696080

3. Gallagher A. FDA approves V116 for prevention of invasive pneumococcal disease and pneumonia. Pharmacy Times. Published June 18, 2024. Accessed October 16, 2024. https://www.pharmacytimes.com/view/fda-approves-v116-for-prevention-of-invasive-pneumococcal-disease-and-pneumonia

4. Halpern L. ACIP votes to recommend pneumococcal 21-valent conjugate vaccine for adult populations. Pharmacy Times. Published July 2, 2024. Accessed October 16, 2024. https://www.pharmacytimes.com/view/acip-votes-to-recommend-pneumococcal-21-valent-conjugate-vaccine-for-adult-populations