Racing rival Pfizer, Merck's Vaxneuvance makes its case for an FDA approval in children

vaccine
Trial data shows that when compared to Pfizer's Prevnar 13, Merck's Vaxneuvance provides comparable protection over shared serotypes and more protection over two unique strains. Data also show the shots are interchangeable in infants. (Pixabay)

Time is of the essence for Merck as the company races with rival Pfizer to gain an FDA approval for its next-generation pneumococcal vaccine in children.

The longer the company can offer kids the most protective vaccine on the market, the better chance it has to gain a foothold against Pfizer's dominant Prevnar franchise. By touting data from two recent trials of its Vaxneuvance at IDWeek, Merck hopes to do just that.

The trials showed that Vaxneuvance, which won FDA approval for adults in July, provides children more protection than Pfizer's Prevnar 13 and is safe for both those who have never been vaccinated and for those who have used Prevnar 13 but have gotten off schedule. In addition to immunizing against the 13 serotypes covered by Prevnar 13, Merck's Vaxneuvance protects against two additional strains—22F and 33F.

In one of the trials, 606 children aged 7 months through 17 years received (PDF) Vaxneuvance or Prevnar 13 as a catch-up shot for those who had never been vaccinated or had gotten off schedule with Prevnar 13. Vaxneuvance provided comparable immune response in 13 shared serotypes and superior immune responses to the two serotypes that Prevnar 13 does not cover, researchers said. 

In the other trial, designed to measure the interchangeability of Vaxneuvance and Prevnar 13, 900 infants were randomized (PDF) into five groups. One of the groups received four shots of Vaxneuvance and another received four shots of Prevnar 13. The other three groups started with Prevnar 13 and switched to Vaxneuvance at shot No. 2, No. 3 and No. 4.

RELATED: On a vaccine roll, Pfizer scores FDA nod for Prevnar 13 follow-up ahead of rival Merck

For the 13 shared serotypes, both the mixed-dose and four-dose regimens of Vaxneuvance provided comparable antibody responses to the four-dose regimen of Prevnar 13, investigators said. 

“Together these studies reinforce the potential of Vaxneuvance to confer immunogenicity for PCV13 serotypes in infants who have previously received one or multiple doses of PCV13 and for the 15 serotypes in Vaxneuvance in children in a catch-up setting,” Luwy Musey, Merck Research Laboratories’ director of biologics and vaccine clinical research, said via email.

Merck and Pfizer have been racing toward the market with their respective next-gen pneumococcal vaccines for years. This summer, Pfizer scored first by nabbing an FDA approval in adults in June. Merck followed a month later, but the company also leads in the effort to vaccinate children.

The vaccines protect against bacteria that can cause pneumonia, meningitis and blood infections.

RELATED: Merck’s nex-gen pneumococcal shot scores FDA nod, setting up high-stakes clash with rival Pfizer

Prevnar 13 generated $5.95 billion in global sales last year. But with 80% of the market consisting of children, its dominance will be threatened if Merck can get there first with Vaxneuvance.

Merck remains on track for submission of a biologics license application (BLA) for Vaxneuvance to the FDA for use in children this year, Musey said.