Merck, locked in next-gen pneumococcal vaccine race with Pfizer, strengthens its lead in childhood use

Merck plans to submit an application for its next-gen pneumococcal vaccine in children later this year. (Merck)

As Merck and Pfizer's next-gen pneumococcal vaccines race toward potential launches in adults later this year, Merck's candidate just ginned up a lead in children. 

Merck's V114 passed safety and efficacy bars in two phase 3 trials, the company said Thursday, giving it a timing advantage over the Pfizer rival. The readout sets the stage for Merck to submit an application for its shot in kids by the end of the year, potentially offering an edge over Pfizer, which doesn't expect late-stage pediatric data on its pneumococcal candidate until 2022. 

In adult use, both rivals have won priority reviews at the FDA. The agency is set to make a decision on Pfizer's 20-valent shot in June and Merck's 15-valent candidate in July.

In an interchangeability study in healthy infants 42 to 90 days old, V114 met both is primary safety and immunogenicity endpoints, Merck said. The Pneu-Direction trial pitted four doses of Prevnar 13 against a mixed-dose schedule of Prevnar 13 followed by Merck's 15-valent candidate. Some infants also received a full, four-dose regimen of V114, the company said.

Immune responses were generally comparable across the 13 serotypes, or strains of pneumococcal disease, covered by both vaccines. Safety also looked similar across the five vaccination groups.

In the Pneu-Plan catch-up study, investigators tested V114 in healthy kids between the ages of seven months and 17 years who'd never had a pneumococcal vaccine, plus those who'd previously received a full or partial regimen of an approved pediatric pneumococcal shot. In the trial, V114 and Prevnar 13 charted similar immune responses across the shots' 13 shared serotypes.

Merck plans to share the detailed results at an upcoming medical congress.

The results help pad the case for healthy infants to potentially switch to Merck's candidate after starting vaccination with the current 13-valent vaccine, the company said. The data also bodes well for the shot's use in a catch-up setting, where it would be used in children who hadn't previously received a pneumococcal shot, or those who may have received a full or partial regimen of another vaccine.

RELATED: Merck pulls close to Pfizer in next-gen pneumococcal vaccine race as FDA fast-tracks 15-strain vaccine

Pfizer's pneumococcal stalwart Prevnar 13 has boasted the title of the world's best-selling vaccine for many years, though that's set to change in 2021 as historic COVID-19 vaccine revenues start to add up.

Merck, for its part, has been on its pneumococcal conjugate vaccine journey for nearly a decade now. The first formulation the company turned out in 2011 “worked pretty well” but wasn't "optimal" in children, Merck’s Luwy Musey, executive director in biologics and vaccines clinical research, told Fierce Pharma in February. Merck stopped the program, made changes and spent several more years to ensure it could hit the market with a “high-quality product," he said. 

In February, Cantor Fitzgerald analysts suggested Pfizer's 20-valent candidate might be "preferable" to Merck's 15-valent shot thanks to its broader coverage, but they noted clinical studies hand the advantage to Merck's V114 in serotype 3. Pfizer's upcoming shot will be essential to maintaining its lead in the lucrative pneumococcal field, while Merck now has the chance to cash in on "a potential blockbuster opportunity," the team said. 

RELATED: Pfizer's 'Prevnar 20' gets in FDA fast lane as next-gen pneumococcal vaccine race heats up with Merck

Pfizer's pediatric data on its 20-valent candidate could come in 2022, teeing up an approval filing late that year, the analysts wrote. If Merck's submission goes to plan at the FDA later this year, the company's vaccine could snare a nod in children in the second or third quarter of 2022.