Merck's 21-Valent Adult-Specific Pneumococcal Vaccine Accrues New Phase 3 and Real World Data

Merck today announced positive results from multiple phase 3 trials for V116, the company’s investigational, 21-valent pneumococcal conjugate vaccine formulated specifically for adults aged 50 and older, at the 13th Meeting of the International Society of Pneumonia and Pneumococcal Diseases (ISPPD) in Cape Town, South Africa.

Data from a number of the studies presented, which comprise the company’s phase 3 STRIDE clinical trial program, were included in the biologics license application (BLA) for the novel vaccine submitted to the US Food and Drug Administration in December 2023. The BLA was subsequently was granted FDA Priority Review, with a PDUFA date set for June 17, 2024.

In addition to data from the company’s phase 3 studies, Merck also announced preliminary results from PNEUMO (Pneumococcal Pneumonia Epidemiology, Urine Serotyping, and Mental Outcomes) a real-world evidence study in the US, which showed that V116 covered 84% of nearly 250 pneumococcal serotypes in a cohort of 2065 adults aged 50 years and older who were hospitalized for community acquired pneumonia (CAP) between 2018 and 2022. Further, the PNEUMO findings demonstrated that approximately 25% of the serotypes detected in the study were covered only by V116 and not by PCV15 or PCV20.

“Invasive pneumococcal disease and pneumococcal pneumonia can cause serious illness, especially in older adults and those with immunocompromising conditions,” Walter Orenstein, MD, professor emeritus of medicine, epidemiology, global health and pediatrics at Emory University and member of Merck’s Scientific Advisory Committee said in the announcement. “These positive data demonstrate the potential for V116 to address an unmet need in adult pneumococcal disease prevention.”

Phase 3 STRIDE program

In addition to subgroup analyses from the STRIDE-3 and STRIDE-6 trials, the main findings from which had previously been reported, Merck presented findings from the STRIDE 7 and STRIDE 9 clinical trials.

STRIDE 7: In a cohort of 304 adults aged 18 years and older living with HIV, V116 was found immunogenic for all 21 serotypes it covers as assessed by geometric mean titer (GMT) of serotype-specific opsonophagocytic (OPA) activity 30 days post-vaccination; immune responses elicited were comparable to those to PCV15+PPSV23 for all 13 shared serotypes. Immune response was higher for the 8 serotypes covered by V116 only, as assessed by serotype-specific OPA GMTs and Immunoglobulin G (IgG) geometric mean concentrations (GMCs) at day 30. V116 was associated with fewer injection-site adverse events compared with PCV15+PPSV23.

STRIDE 9. The randomized, double-blind active comparator study evaluated V116 in 450 Japanese adults aged 65 years and older who had no history of receiving pneumococcal vaccine. When serotype-specific OPA responses were measures at baseline and again at 30 days post-vaccination, researchers found noninferior immune responses to V116 for the 12 serotypes shared with PPSV23 and serotype 15B (included in PPSV23 but not in V116). They also reported higher immune response for serotypes covered exclusively by V116. Safety profiles were comparable for the 2 vaccines.

The PNEUMO US study was designed to assess pneumococcal serotype distribution in a population of older adults with CAP treated in 3 hospitals in Tennessee and Georgia. Investigators used a novel urinary antigen assay to detect antigens from 30 pneumococcal serotypes, including all those found in PCV15, PCV20, and V116, excluding 15B. The 84% coverage by V116 of the 242 serotypes detected was greater than the approximately two-thirds (64%) covered by PCV20.

Merck also presented phase 3 data at ISPPD from the phase 3 STRIDE-4 (NCT05464420) and STRIDE-5 (NCT05526716) clinical studies.

Source: Merck announces positive data on V116, an investigational, 21-valent pneumococcal conjugate vaccine specifically designed for adults, demonstrated immune responses in adults. News release. Merck. March 19, 2024. Accessed March 19, 2024. https://www.merck.com/news/merck-announces-positive-data-on-v116-an-investigational-21-valent-pneumococcal-conjugate-vaccine-specifically-designed-for-adults-demonstrated-immune-responses-in-adults/