V116 Well-Tolerated With Broad Immune Responses in Pneumococcal Vaccine-Naïve Older Adults

V116 (21-valent pneumococcal conjugate vaccine [PCV21]; Capvaxie; Merck) elicited immune responses to all included pneumococcal serotypes and the cross-reactive 15B serotype while demonstrating a comparable and tolerable safety profile comparable with the 23-valent pneumococcal polysaccharide vaccine (PPSV23; Pneumovax; Merck) in vaccine-naïve Japanese adults aged 65 and older, according to results published by investigators in Vaccine.¹

Older adults are at increased risk of invasive pneumococcal disease. | Image Credit: © InsideCreativeHouse - stock.adobe.com

Purpose of Further V116 Comparisons

Already investigated in numerous trials, V116 has become a recommended and approved option for the prevention of serious, invasive disease or pneumonia caused by infection with Streptococcus pneumoniae. Investigators have demonstrated robust immunogenicity against all 21 pneumococcal serotypes covered by the vaccine in both vaccine-experienced and vaccine-naïve patients. Concurrently, it was shown in the phase 3 STRIDE-10 trial to be noninferior to PPSV23 for 12 shared vaccine serotypes.^2-4

This vaccine is a critical preventative measure against serious complications from pneumococcal disease, which can—depending on the nature of the bacteria and its invasiveness—lead to significant morbidity and mortality. Experts agree that older adults, especially those aged 65 and older, constitute a population at heightened risk of severe disease. With a population growing increasingly older—notably in Japan, where a large proportion of the population are aged 65 and older—it is critical to evaluate the efficacy and safety of more recent vaccine candidates compared with previous standard options.^1,3,5

Investigators of a previously conducted phase 1 trial conducted among healthy pneumococcal vaccine-naïve Japanese adults aged 20 or older demonstrated robust immune responses for all V116 serotypes in patients vaccinated with PCV21, while eliciting geometric mean titer ratios favorable for protection from the serotypes. To more comprehensively evaluate V116 in comparison with PPSV23, the current authors conducted STRIDE-9, a randomized, double-blind, active comparator-controlled phase 3 trial to evaluate the tolerability and immunogenicity of V116 compared with PPSV23 in vaccine-naïve older adults.^1,6,7

Robust Immunogenicity Elicited From V116 Compared With PPSV23

Between January 2023 and May 2023, individuals who were vaccine-naïve were recruited across 8 health care centers in Japan. Enrollees were randomized 1:1 to receive a single dose of V116 or PPSV23. Blood samples were taken at Day 1 and Day 30 of the study to measure functional antibodies. A total of 450 adults were randomized (V116, n = 225; PPSV23, n = 225); the overall mean age of the population was 70.7 years.¹

V116 was found to be noninferior to PPSV23 for all 12 serotypes shared between the vaccines and for 15B, according to the investigators. Opsonophagocytic activity (OPA) geometric mean titers were numerically higher compared with PPSV23 for the remaining 8 unique serotypes and for the cross-reactive 6C.¹

Compared with PPSV23, V116 was superior regarding the proportion of participants with a 4-fold or higher increase in OPA from day 1 to day 30 for the 8 unique PCV21 serotypes. For the 12 shared serotypes and the cross-reactive 6C, the proportion of patients with 4-fold or more increases were generally comparable between both V116 and PPSV23, according to the investigators.¹

Despite a significant portion (40%) of patients in each vaccine group (V116 = 38.2%; PPSV23 = 44.4%) experiencing at least 1 or more adverse events (AE), safety remained positive overall. Most reported AEs were injection-site pain, injection-site erythema, fatigue, and injection-site swelling. Importantly, the proportions of patients experiencing these common AEs were comparable between the V116 and PPSV23 cohorts.¹

Insights From Japanese Population Can Inform US Decisions

In results aligned with those from other studies of V116, specifically from the STRIDE family of trials, the vaccine demonstrated significant immune responses towards a series of pneumococcal-causing vaccine serotypes. For populations at increased risk of serious pneumococcal disease, reaffirming the safety and efficacy of recommended vaccine options remains essential to determine their effectiveness compared with alternatives and assess the dynamics of their immune response.^1,8

Though these results were garnered from a Japanese population, health care professionals from the United States and across the globe can utilize this data and discover key insights on pneumococcal vaccination strategies for older adults. Protecting populations at the highest risk of serious complications from vaccine-preventable diseases is crucial for public health.¹

REFERENCES

1. Kishino H, Inoue S, Matsuoka O, et al. A phase 3 randomized trial (STRIDE-9) to evaluate the safety, tolerability, and immunogenicity of V116, a population-specific pneumococcal conjugate vaccine, in pneumococcal vaccine-naïve Japanese adults ≥65 years of age. Vaccine. 2025;62(30):127456. doi:10.1016/j.vaccine.2025.127456

2. Gallagher A. V116 Elicits Noninferiority Immune Response Compared with PPSV23 for Pneumococcal Disease. Pharmacy Times. Published May 6, 2024. Accessed August 11, 2025. https://www.pharmacytimes.com/view/v116-elicits-noninferiority-immune-response-compared-with-ppsv23-for-pneumococcal-disease

3. Gallagher A. V116 Demonstrates Positive Immunogenicity for 21 Pneumococcal Serotypes. Pharmacy Times. Published March 22, 2024. Accessed August 11, 2025. https://www.pharmacytimes.com/view/v116-demonstrates-positive-immunogenicity-for-21-pneumococcal-serotypes

4. Gallagher A. FDA Approves V116 for Prevention of Invasive Pneumococcal Disease and Pneumonia. Pharmacy Times. Published June 18, 2024. Accessed August 11, 2025. https://www.pharmacytimes.com/view/fda-approves-v116-for-prevention-of-invasive-pneumococcal-disease-and-pneumonia

5. Statistics Bureau of Japan Current population estimates as of October 1, 2022. https://www.stat.go.jp/english/data/jinsui/2022np/index.html (2022). Accessed August 11, 2025.

6. Haranaka M, Yono M, Kishino H, et al. Safety, tolerability, and immunogenicity of a 21-valent pneumococcal conjugate vaccine, V116, in Japanese healthy adults: A Phase I study. Human Vacc & Immunother. 2023;19(2):2228162. doi:10.1080/21645515.2023.2228162

7. Safety and Immunogenicity of V116 in Vaccine-naïve Japanese Older Adults (V116-009, STRIDE-9). National Library of Medicine. Last Updated October 2, 2024. Accessed August 11, 2025. https://clinicaltrials.gov/study/NCT05633992

8. Halpern L. Pneumococcal 21-Valent Conjugate Vaccine Generates Positive Response in Adults at Increased Risk of Disease. PharmacyTimes. Published October 21, 2024. Accessed August 11, 2025. https://www.pharmacytimes.com/view/pneumococcal-21-valent-conjugate-vaccine-generates-positive-response-in-adults-at-increased-risk-of-disease