MSD takes on Pfizer's Prevnar with new Capvaxive approval

MSD has claimed new territory for pneumococcal vaccines after getting FDA approval for use of its Capvaxive shot in vulnerable children aged two to 17.

Capvaxive, which covers 21 strains of Streptococcus pneumoniae, has been approved since 2024 for the prevention of invasive pneumococcal disease and pneumococcal pneumonia in adults, but until now has had no role to play in paediatric vaccinations, which are dominated by Pfizer's rival Prevnar range.

While Prevnar – which comes in 13- and 20-valent versions – is used in primary paediatric pneumococcal vaccinations, Capvaxive now becomes an option specifically for children who have completed that initial course but have one or more chronic medical conditions, such as diabetes or lung, liver, heart, or kidney disease, that put them at an increased risk of pneumococcal disease.

MSD has an older 13-valent jab, Vaxneuvance, which is indicated for primary paediatric vaccinations, as well as for protecting adults, but its two shots are a long way behind Pfizer's Prevnar range, which made global sales of nearly $6.5 billion last year. For comparison, Capvaxive recorded $759 million in global sales last year, while Vaxneuvance brought in another $825 million.

The new approval gives MSD – which is known as Merck & Co in the US and Canada – a niche for Capvaxive free of Prevnar competition, as both rivals work on new vaccines which promise to extend the number of strains covered even further.

The FDA approval is based on data from the phase 3 STRIDE-13 trial, which compared Capvaxive to MSD's Pneumovax 23, which covers 23 serotypes but is based on an older polysaccharide technology that in general does not stimulate immune responses as strongly as the newer conjugate vaccines.

The results showed that Capvaxive was at least as effective as Pneumovax 23 at stimulating an immune response against the 23 strains covered by the polysaccharide-based shot, and conferred protection to nine more that are unique to the newer vaccine.

"Children and adolescents with certain chronic conditions are at an increased risk for pneumococcal disease, including pneumonia, meningitis, and bloodstream infections," said STRIDE-13 investigator Dr Rotem Lapidot, who is chief of paediatric infectious diseases at Rambam Health Care Campus.

"This approval recognises the potential of Capvaxive to deliver additional protection by including serotypes not contained in approved primary paediatric…series, and represents a new approach to helping protect children and adolescents at increased risk for pneumococcal disease."

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