Merck (MSD) has reported positive results from the Phase III PNEU-PATH and PNEU-DAY trials of its investigational 15-valent pneumococcal conjugate vaccine, V114, against pneumococcal disease.
Pneumococcal disease is an infection caused by bacteria called Streptococcus pneumoniae.
V114 is made of pneumococcal polysaccharides from 15 serotypes conjugated to a CRM197 carrier protein and includes serotypes 22F and 33F.
In the PNEU-PATH trial, healthy participants aged 50 years or above received V114 or PCV13 followed by Pneumovax 23 a year later.
The trial analysed the safety, tolerability and immunogenicity of V114 followed by an administration of Pneumovax 23.
The primary and secondary endpoints of the study were serotype specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) at 30 days post-vaccination with Pneumovax 23 and with V114 or PCV13, respectively.
Immune responses after vaccination with Pneumovax 23 were comparable in both vaccination groups for the 15 serotypes in V114.
Data showed that at 30 days post-vaccination with either V114 or PCV13, immune responses were comparable for both groups across the 13 serotypes shared by the conjugate vaccines and higher in the V114 group for serotypes 22F and 33F, the two serotypes not included in PCV13.
OPA response is a measure of vaccine-induced functional antibodies.
Secondly, the Phase III PNEU-DAY trial analysed the safety, tolerability and immunogenicity of V114 followed by Pneumovax 23 six months later.
Participants were aged between 18 and 49 years and were at increased risk for pneumococcal disease due to an underlying condition, behavioural habits, or living in an environment with high transmission risk.
The primary endpoints were serotype specific OPA GMTs at 30 days post-vaccination with either V114 or PCV13.
In this group, V114 generated immune responses generally comparable to PCV13 for the 13 shared serotypes and higher immune responses for serotypes 22F and 33F at 30 days post-vaccination.
V114 was well tolerated in both trials with a safety profile consistent with previously reported ones.
Merck Research Laboratories chief medical officer Dr Roy Baynes said: “These data provide important information about the potential for V114 followed by Pneumovax 23, a polysaccharide vaccine included in more than 90% of age-based adult pneumococcal immunisation programmes globally, to help protect healthy adults and adults who are at increased risk for pneumococcal disease.”