Merck (MSD) has reported that its pneumococcal 15-valent conjugate vaccine, Vaxneuvance, met the key immunogenicity and safety goals in pivotal Phase III PNEU-PED (V114-029) trial in healthy infants.

The vaccine comprises purified capsular polysaccharides from S. pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F and 33F separately conjugated to the CRM197 carrier protein.

Last month, the US Food and Drug Administration (FDA) approved Vaxneuvance for use in adults aged 18 years or above for active immunisation to prevent invasive disease caused by the 15 S. pneumoniae serotypes present in the vaccine.

The multi-centre, randomised, double-blind, active-comparator-controlled Phase III PNEU-PED trial analysed the safety, tolerability and immunogenicity of Vaxneuvance in infants enrolled at the age of 42 to 90 days.

The trial involved 1,720 subjects, who were administered a four-dose regimen of either Vaxneuvance or the licensed 13-valent pneumococcal conjugate vaccine (PCV13) at the age of two, four, six, and 12 to 15 months.

Top-line data from the trial showed that Vaxneuvance demonstrated a safety profile that was comparable to PCV13 on receiving any vaccine dose.

At 30 days after the third dose, Vaxneuvance showed non-inferiority to PCV13 for all 13 shared serotypes depending on serotype-specific response rates.

Furthermore, based on serotype-specific IgG geometric mean concentrations (GMCs), Vaxneuvance was not inferior for 12 out of the 13 shared serotypes.

Based on serotype-specific IgG GMCs, Vaxneuvance was demonstrated to be non-inferior to PCV13 for all 13 shared serotypes at 30 days after the fourth dose.

On the secondary goals, Vaxneuvance showed statistically superior immune responses versus PCV13 for shared serotype 3 and unique serotypes 22F and 33F based on certain criteria.

In the Phase III PNEU-LINK (V114-031) trial, Vaxneuvance was generally well-tolerated with a safety profile in line with PCV13 in healthy infants.

Merck Research Laboratories global clinical development head and senior vice-president Dr Roy Baynes said: “At Merck, our goal is to design pneumococcal vaccines that target strains causing the greatest proportion of disease while maintaining a strong immune response to these serotypes.

“With the inclusion of serotypes 22F and 33F, Vaxneuvance has the potential to play an important role in the prevention of invasive pneumococcal disease in children.”

The company intends to submit a supplemental regulatory licensure application to the FDA for Vaxneuvance in children before the end of this year.

In May 2021, Merck reported that its 15-valent pneumococcal conjugate vaccine candidate, V114, met the primary immunogenicity and safety goals in two Phase III paediatric clinical trials, PNEU-DIRECTION and PNEU-PLAN.