A Pfizer vaccine that addresses 20 types of pneumococcal bacteria has won FDA approval, giving the company a successor to a blockbuster product and the edge in a race to protect against more of these strains that can lead to serious infections, such as pneumonia and meningitis.
Pneumococcal infections are caused by the bacteria Streptococcus pneumoniae. There are more than 90 strains. As its name conveys, Prevnar 20 vaccine protects against 20 of these strains, improving on Prevnar 13, a Pfizer product that accounted for more than $5.8 billion in global sales last year. Approval of Prevnar 20 covers adults 18 and older.
Prevnar 20 is what’s called a conjugate vaccine. The antigens for the vaccine are polysaccharides, chains of sugar molecules from the bacteria’s outer coat. The polysaccharides are bonded to a carrier protein. By carrying more of these polysaccharides, a vaccine can protect against more strains.
According to Pfizer, the seven additional strains covered in Prevnar 20 account for about 40% of all pneumococcal disease cases and deaths in the U.S. All 20 of the strains are estimated to be responsible for more than half of all U.S. cases of invasive pneumococcal disease, which include bacteremia and meningitis, as well as community-acquired pneumonia.
With Prevnar 20’s approval, Pfizer can claim it offers a vaccine that protects against more of the disease-causing pneumococcal strains than any other vaccine currently available. However, competition is on the way. Though Merck’s V114 protects against five fewer pneumococcal strains than Prevnar 20, the pharmaceutical giant is further along in clinical testing of its candidate in children. Last month, Merck reported positive preliminary results of a Phase 3 pediatric test of its vaccine. An FDA decision on V114 in adults is expected in mid-July.
Other companies are in earlier stages with their pneumococcal vaccines. The lead candidate of Vaxcyte is VAX-24, a pneumococcal vaccine candidate designed to protect against 24 strains. The Foster City, California-based biotech is in preclinical development with VAX-24. The lead candidate of Affinivax also addresses 24 pneumococcal strains. The Cambridge, Massachusetts-based startup has advanced that candidate, ASP3772, through Phase 2 testing under a collaboration with pharmaceutical company Astellas. The candidate is also in Phase 1 testing in toddlers.
Prevnar 20 was submitted to the European Medicines Agency in February. That review is ongoing. Following the FDA approval of Prevnar 20, Pfizer said that the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices is expected to meet in October to discuss and update its recommendations on the safe and appropriate use of pneumococcal vaccines in adults.
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