The FDA has approved the world’s first pneumococcal disease vaccine designed for adults, signing off on Merck’s Capvaxive (formerly V116) and positioning it to become the primary shot used by seniors to protect against the bacterial infection.
While the nod applies to people at least 18 years of age, Capvaxive is specifically adapted for patients age 50 and older as the 21 serotypes it covers account for 84% of the pneumococcal disease of people in the age group, according to epidemiologic data from the CDC.
This compares to a 52% figure in the same population for the 20 serotypes covered by the world’s dominant pneumococcal disease vaccine, Pfizer’s Prevnar 20, which is allowed both in children and adults. There have not been any studies conducted to compare the efficacy of Capvaxive and Prevnar 20.
The approval of Capvaxive is backed by four phase 3 trials, including one that pitted it against Prevnar 20 on immune responses. The study showed V116’s non-inferiority in the 10 serotypes common to both vaccines and superiority in 10 of its 11 unique serotypes.
“We have eight serotypes in V116 that are not in any currently licensed vaccine. Those eight serotypes are responsible for 30% of invasive pneumococcal disease in adults 65 years of age and older,” Heather Platt, M.D., Merck’s pneumococcal vaccine lead, said in an interview with Fierce Pharma ahead of the approval.
The accelerated nod for Capvaxive remains contingent upon verification of clinical benefit in a confirmatory study. On June 27, the CDC will assemble the Advisory Committee on Immunization Practices (ACIP) to discuss recommendations for the use of Capvaxive.
Merck took the lead in developing a pneumococcal vaccine for adults and now stands to benefit as other companies developing shots for adults in the indication lag behind.
The most serious challenger is likely California biotech Vaxcyte, which is developing a 24-valent shot which covers all the serotypes in Prevnar 20, plus four unique strains, and has fared well in a phase 2 trial against the Pfizer powerhouse. The company also has a 31-valent pneumococcal vaccine in its pipeline.
The development of a pneumococcal shot adapted for adults has been a long time coming. The first vaccine for the infection, a polysaccharide type, hit the market in 1977. When the first conjugate vaccine, Prevnar 7 (PCV7), arrived in 2000, it significantly reduced the disease burden in both children and adults.
But while subsequent conjugate vaccines with added serotypes were increasingly effective in protecting children, the same was not true for their efficacy in adults and it’s taken researchers a while to figure out why.
“What’s happened over time, because we have the ability to look at good surveillance data, what we’ve seen is that the serotypes causing disease in children are actually different than the ones causing disease in adults,” Platt said.
There are more than 150,000 adults each year in the United States who are hospitalized with pneumococcal disease. With serious complications including bacteremia and pneumococcal meningitis, the case death rate for those hospitalized is 14%.
Since the development of pneumococcal disease vaccines began, protecting children has been the paramount concern. But in recent years, that has begun to change, according to Platt.
“As we meet with the CDC work group and listen to the discussions at ACIP, there is a growing understanding of the value of adult vaccination,” Platt said.
Merck will target a variety of individuals with Capvaxive. In the U.S., approximately 34% of adults age 65 and older have never received a pneumococcal shot. But even those who have been vaccinated can benefit from Capvaxive and the new serotype protection that it provides, Platt said.
There also is a significant population of adults of all ages who have chronic medical conditions—such as lung disease, liver disease, heart disease—who are at increased risk if they contract pneumococcal disease. Of this group, only 22% have been vaccinated for pneumococcal disease.
“We have to understand, what’s the best way to create opportunities for protection,” Platt said. “Do people have access? Is it because they can’t get to the pharmacy? Or do they not understand that this is an important vaccine that can help prevent disease?”
Merck now has a chance to grab a larger share of the pneumococcal vaccine market. In 2023, the company scored $665 million in sales of its 15-valent pneumococcal shot Vaxneuvance (formerly V114), which was approved in 2021. While the Prevnar franchise still is the market dominator with sales last year of $6.4 billion, Merck’s shot has contributed to a slowdown in the Pfizer product’s sales growth from 20% in 2022 (PDF) to 2% last year.
“V116 is an adult-specific vaccine. It’s intended to complement those pediatric vaccines which are critical to protection,” Platt said. “We’re looking forward to the ACIP vote with the intent of improving public health.”