Pfizer rolls out next-gen pneumococcal vaccine with FDA win, beating Merck's 15-valent candidate to the punch
Merck and Pfizer have been locked in a yearslong battle for a next-gen pneumococcal vaccine winner, with the latter looking to one-up — or should we say seven-up — its standard 13-valent shot. Now, Pfizer has nosed out a win with the FDA’s backing, leaving Merck and its 15-valent shot waiting in the wings.
Pfizer said on Tuesday that the FDA has approved its Prevnar 20 for adults 18 years and older — just over a month before Merck’s PDUFA date for its V114. The CDC’s Advisory Committee on Immunization Practices is scheduled to meet in October to discuss and update recommendations on the use of pneumococcal vaccines, according to Pfizer.
“With a single injection, PREVNAR 20 provides adults with strong and meaningful protection against serotypes responsible for the majority of circulating pneumococcal disease around the world,” Kathrin Jansen, SVP and head of vaccine R&D at Pfizer, said in a statement.
There are currently two main types of pneumococcal vaccine: pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPSV). Both contain polysaccharides taken from serotypes of S. pneumoniae bacteria, which cause patients’ immune systems to develop antibodies that will later recognize that polysaccharide.
Merck came out with its 23-valent PPSV, Pneumovax 23, back in 1983. However, PPSVs have been shown to have poor performance in younger children. As a solution, drugmakers have developed “conjugated” vaccines, in which the polysaccharides are attached to a carrier protein.
Pfizer got a 7-valent conjugate vaccine approved in 2000, followed by its 13-valent megablockbuster Prevnar 13 in 2010. Prevnar 20 covers all 13 strains that Prevnar 13 does, plus 8, 10A, 11A, 12F, 15B, 22F and 33F. The additional seven strains account for about 40% of all pneumococcal disease cases and deaths in the US, according to Pfizer.
Prevnar 13 raked in $5.8 billion in 2020 and was once the world’s best-selling vaccine in pre-Covid times. The follow-on won’t bring in the $26 billion that Pfizer’s Covid-19 vaccine is expected to in 2021, but Prophecy Market Insights expects the global pneumococcal vaccine market to grow from $8.1 billion in 2020 to $13.5 billion by 2030.
The vaccine was fast tracked by the FDA back in 2017, then given priority review in 2018. The FDA’s decision was based on Phase I and II data, as well as three Phase III trials that enrolled a total of 6,000 adults.
Pfizer unveiled data from one of those studies — a pivotal Phase III that enrolled 902 adults with no history of pneumococcal vaccination — back in October at IDWeek. The study compared Prevnar 20’s performance to Prevnar 13 and Pneumovax 23. All 20 serotypes induced “robust responses” across three age cohorts (18 to 49, 50 to 59, and 60 or older), according to Pfizer.
In the focus group of adults 60 and older, Prevnar 20’s response was non-inferior to all serotypes in common with Prevnar 13, and six of the seven new serotypes in common with Pneumovax 23 one month after vaccination. Serotype 8 just barely missed the non-inferiority lower bound criteria, but showed immune responses in other parameters, the company said. Immune responses to Prevnar 20 in the two younger age cohorts were non-inferior to the same vaccine’s responses in adults 60 to 64 years old.
Pfizer also read out data from infant trials (enrolling babies 42 to 98 days old), which showed a consistent safety profile compared to Prevnar 13 and immune response to all 20 serotypes one month after the third dose. Booster responses were recorded for all serotypes a month after the fourth dose.
Merck isn’t throwing in the towel just yet. Last month — even as it looked like Prevnar 20 might beat it to market — the Kenilworth, NJ-based pharma read out topline results from two Phase III pediatric studies, and said it’s on track to submit a supplementary BLA by the end of the year.
V114 covers the 13 serotypes covered by Prevnar 13, plus an additional two: 22F and 33F.
“Results from these studies support the potential of V114 to confer immunogenicity for PCV13 serotypes in infants who have previously received one or multiple doses of PCV13, and for the 15 serotypes in V114 in children in a catch-up setting,” Merck Research Labs CMO Roy Baynes said.
As Merck and Pfizer duke it out, a 24-valent candidate is in the making that hopes to topple them both. Vaxcyte, formerly known as SutroVax, is in early development with VAX-24 and expects to file an IND in the first half of 2022. The company pulled in $249 million in an IPO last June, and says a Phase I/II readout would follow between late 2022 and early 2023.
On Jan. 11 — the same day the FDA accepted a BLA for V114 — Merck filed a lawsuit challenging three of Pfizer’s patents relating to its pneumococcal conjugate compositions. The company has asked a judge to rule that V114 “does not and will not infringe any valid claim of these three patents.”