Pfizer and Merck & Co. are racing ahead with next-gen pneumococcal vaccines in what's likely to be a multibillion-dollar field—and Pfizer has some new data to boast for its candidate, a hoped-for followup to its mega-successful Prevnar 13.
After three shots of the new, broadly targeted vaccine in infants, researchers found that the vaccine has a safety profile similar to Prevnar 13, which pulled in $5.8 billion last year. The newer vaccine induced immune responses to all 20 serotypes of the virus it’s designed to protect against—the 13 included in Prevnar 13 plus an additional seven.
Overall, the “findings are encouraging and should support the program’s advancement to phase 3,” Pfizer’s head of vaccine R&D Kathrin Jansen said in a statement.
The phase 2 study is ongoing and the recipients will get one more dose. Pfizer aims to discuss phase 3 plans with regulators after the study wraps up, Jansen added.
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Aside from the infant study, the company has completed enrollment for three phase 3 studies in adults, Pfizer said Monday. If those trials are successful, Pfizer expects to file the new vaccine with regulators late next year.
Pfizer's advancing the candidate as a follow-up to Prevnar 13, which happens to be the world's bestselling vaccine. But it’s also going up against Merck, whose 15-valent pneumococcal vaccine is in phase 3 testing. In January, Merck's shot scored an FDA breakthrough therapy designation in patients aged 6 weeks to 18 years. Pfizer’s shot won the breakthrough tag in adults last year.
In a note to clients Monday, Cantor Fitzgerald analyst Louise Chen wrote that it seems Merck is ahead with its testing in the pediatric patient group, and she wondered whether Pfizer will start by targeting the adult market. Merck presented phase 2 data in patients 6 weeks old to 12 weeks old back in May. Chen wrote that the time to market for the “competing programs will be a key factor in determining how these markets shake out.”
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As is usual, the vaccines will rely on recommendations from CDC vaccine experts, and doctors are unsure how those recommendations will come in for the newer vaccines. Some don’t believe Merck’s 15-valent vaccine adds enough value to score a preferential recommendation over Prevnar 13, Chen wrote. It’s also unclear whether infants who’ve had four Prevnar 13 doses should receive a newer vaccine, or if those who haven’t had all four doses should switch to a next-gen shot, among other uncertainties.