Merck’s Pneumonia Vaccine Candidate Blossoms in Phase 3 Trial

By T. Chakraborty, Ph.D.

On June 22, Merck announced encouraging results from its two Phase 3 clinical studies (PNEU-WAY and PNEU-FLU) that evaluated its 15-valent pneumococcal conjugate vaccine, V114.

Pneumococcal disease, an infection caused by Streptococcus pneumoniae is a major cause of morbidity in humans globally. The Centres for Disease Control and Prevention (CDC) estimates approximately 150,000 hospitalizations every year, making it a socioeconomic burden on patients [1]. The most vulnerable age groups are the immunosuppressed, especially children below 2 years, and adults above 65. With passing time, the bacteria keep evolving, resulting in the formation of highly aggressive strains (serotypes). This increases the risk for non-intrusive illnesses such as pneumonia, sinusitis, and otitis media and intrusive illnesses such as bacteremia, bacteremic pneumonia, and meningitis.

V114, a Next-Generation Pneumococcal Vaccine

V114 is a 15-valent investigational pneumococcal conjugate for the prevention of pneumococcal disease in adults and children. It consists of polysaccharides from 15 different serotypes of pneumococcus conjugated to a CRM197 carrier protein, the most notable being polysaccharides from 2 serotypes 22F and 33F. These serotypes are associated with invasive forms of pneumococcal disease and are not present in currently licensed vaccines approved for adult use [2].

PNEU-WAY

PNEU-WAY is a Phase 3, multicenter trial consisting of 302 participants who are immunocompromised due to HIV infection. Of them, 152 patients received V114 while the rest received currently available 13-valent conjugate vaccine PCV13. V114 met its primary immunogenicity objective, as measured by serotype-specific opsonophagocytic activity (OPA), Geometric Mean Titers (GMTs) and Immunoglobulin G (IgG) Geometric Mean Concentrations (GMCs) for all 15 serotypes contained.

Further comparative analyses demonstrated that immunogenicity objectives for the 13 shared serotypes were comparable between the two vaccine conjugates. Importantly, immune responses were higher in the V114 group, thanks to the presence of two additional invasive serotypes, 22F and 33F. No safety concern was noted in this trial.

PNEU-FLU

PNEU-FLU is a Phase 3, multicenter, randomized, double-blind, placebo-controlled study consisting of 1200 healthy participants 50 years or older who received the flu vaccine. Participants either received V114 concomitantly with the quadrivalent influenza vaccine (QIV) or non-concomitantly 30 days post the flu vaccine. OPA GMTs and influenza strain-specific hemagglutination inhibition (HAI) GMTs showed that concomitant administration of V114 was non-inferior to non-concomitant administration. The safety profiles were also comparable between the two groups.

This drug conjugate is currently evaluated in 16 clinical trials that are focussed to assess the safety, tolerability, and immunogenicity of the vaccine in a diverse range of patients who are highly susceptible including immunocompromised patients. In the future, Merck plans to file for licenses with the USFDA and other global regulatory authorities based on additional data as they come to the forefront from the Phase 3 development program.

Dr. Luwy Musey, Executive Director in Biologics, Vaccine Clinical Research, said, “Certain populations are at greater risk for pneumococcal disease, reinforcing the importance of investigating new interventions focused on their specific needs. Results from these first two Phase 3 studies of V114 are encouraging and we look forward to sharing additional data in the future from our ongoing clinical development program, including our pivotal studies assessing the immunogenicity of V114 and its potential to protect against the serotypes most likely to cause invasive disease.”

Earlier this year Pfizer also announced exciting results from their 20-valent pneumococcal conjugate vaccine, 20vPnC for treatment in healthy adults. With the first two trials of V114 showing encouraging data, both these pharma giants are headed towards a two-way rivalry [2,3].

Editor: Rajaneesh K. Gopinath, Ph.D.

Related Article: FDA Okays Merck ‘s Combination Antibiotic for Hospital-Acquired Bacterial Pneumonia

References

1. https://www.cdc.gov/pneumococcal/about/facts.html
2. https://investors.merck.com/news/press-release-details/2020/Merck-Announces-That-V114-Its-Investigational-15-valent-Pneumococcal-Conjugate-Vaccine-Met-Safety-and-Immunogenicity-Objectives-in-Initial-Phase-3-Studies-in-Adults/default.aspx
3. https://investors.pfizer.com/investor-news/press-release-details/2020/Pfizer-Announces-Top-Line-Results-from-Phase-3-Study-of-20-Valent-Pneumococcal-Conjugate-Vaccine-in-Pneumococcal-Vaccine-Nave-Adults-Aged-18-Years-or-Older/default.aspx

Author

Tulip Chakraborty