V 116, an investigational, 21-valent pneumococcal conjugate vaccine specifically designed to protect adults, demonstrated superior immunogenicity for 10 of 11 unique serotypes compared to PCV20 in adults 50 years of age and older

The trial evaluated the immunogenicity, tolerability and safety of V 116 compared to PCV20 (pneumococcal 20-valent conjugate vaccine) in adults who had not previously received a pneumococcal vaccine.

Results from the study’s primary objectives include: i. In adults 50 years of age and older (Cohort 1), V 116 elicited non-inferior immune responses compared to PCV20 for all 10 serotypes common to both vaccines as measured by serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) at Day 30. ii. Immune responses elicited by V 116 were superior for 10 of 11 serotypes included in V 116 but not in PCV20 as measured by OPA GMTs at Day 30 and the proportions of patients with a greater than or equal to four-fold increase in OPA from Day 1 to Day 30. iii. In adults 18 to 49 years of age (Cohort 2), V 116 elicited non-inferior immune responses (immunobridged) compared to adults 50 to 64 years of age, as assessed by serotype-specific OPA GMTs 30 days post-vaccination. iv. Across both cohorts, V 116 had a safety profile comparable to PCV20. Detailed findings will be presented at World Vaccine Congress West Coast at 4:50 p.m. EST. The company announced topline results of the STRIDE-3 trial earlier this year.

According to CDC data from 2018-2021, the serotypes covered by V 116 are responsible for approximately 83% of invasive pneumococcal disease in individuals 65 years of age and older. V 116 includes eight unique serotypes not covered by currently licensed pneumococcal vaccines, which were responsible for approximately 30% of invasive pneumococcal disease in individuals 65 years of age and older, based on the same CDC data. If approved, V 116 would be the first pneumococcal conjugate vaccine specifically designed for adults.

“These results provide strong evidence to support the immunogenicity of V 116 compared to the standard of care in the prevention of invasive pneumococcal disease and pneumococcal pneumonia in adults,” said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “We are excited by the potential of V 116 to impact public health through primary prevention through the use of a population-specific strategy that targets the serotypes responsible for the majority of invasive pneumococcal disease in adults.”

“Invasive forms of pneumococcal disease can cause serious and sometimes life-threatening complications, such as pneumococcal pneumonia, pneumococcal meningitis and bacteremia, especially for older or immunocompromised adults,” said Dr. Sady Alpizar, Clinical Research Trials of Florida, Inc., and a principal investigator of the study. “These encouraging results demonstrate that V 116 has the potential to help prevent invasive pneumococcal disease among vulnerable populations.

The V 116 Phase III clinical development program is composed of eight trials (n=8,830) investigating the safety, tolerability and immunogenicity of V 116 in various adult populations. These include adults with and without chronic medical conditions associated with an increased risk of pneumococcal disease, as well as individuals who previously received a pneumococcal vaccine. An overview of the late-stage development program is available here.

Study Design and Additional Data from STRIDE-3: STRIDE-3 (NCT05425732) is a Phase III randomized, double-blind, active comparator-controlled study evaluating the safety, tolerability, and immunogenicity of V 116 compared to PCV20 in adults 18 years of age and older who had not previously received a pneumococcal conjugate vaccine (n=2,663). Participants were randomized to receive a single dose of either V 116 or PCV20.

Primary endpoints across both cohorts included safety, serotype-specific OPA GMTs 30 days post-vaccination and percentage of participants with greater than or equal to four-fold rise from baseline in serotype-specific OPAs. Cohort 1 enrolled participants 50 years of age and older (n=2,362) who were randomized 1:1 to receive a single dose of either V 116 or the comparator, PCV20. Key findings from primary endpoints include: i. V 116 was non-inferior to PCV20 for the 10 serotypes common to both vaccines (3, 6A, 7F, 8, 10A, 11A, 12F, 19A, 22F, 33F), as assessed by serotype-specific OPA GMTs 30 days post-vaccination. ii. V 116 was superior to PCV20 for 10 of 11 serotypes included in V 116 but not in PCV20 (9N, 15A, 16F, 17, 20A, 23A, 23B, 24F, 31, 35B), as assessed by serotype-specific OPA GMTs 30 days post-vaccination and the proportions of patients with a greater than or equal to four-fold increase in OPA from Day 1 to Day 30. Immune responses were observed for serotype 15C in participants receiving V 116, but these did not meet criteria for statistical superiority.

Cohort 2 enrolled participants 18-49 years of age (n=301) who were randomized 2:1 to receive a single dose of either V 116 or comparator, PCV20. Results from primary endpoints showed immune responses elicited by V 116 in participants 18-49 years of age were non-inferior (immunobridged) compared to participants 50-64 years of age for all 21 serotypes, as assessed by serotype-specific OPA GMTs 30 days post-vaccination. Across both cohorts, V 116 had a safety profile comparable to PCV20. Participants administered V 116 and PCV20 who reported at least 1 adverse event (AE) were 61.7% and 67.2%, respectively. There were no vaccine-related serious AEs or vaccine-related deaths in the study.