FDA expands Capvaxine indication to include adolescent patients at risk for pneumococcal disease

The FDA has expanded the approval of Merck’s Capvaxine (Pneumococcal 21-valent conjugate vaccine) to include adolescents ages 2 to 17 at an increased risk for pneumococcal disease, according to a news release published today.

Adolescents with one or more of the following medical conditions may be at an increased risk of pneumococcal disease:

• diabetes mellitus
• chronic heart disease
• chronic kidney disease
• chronic liver disease
• chronic lung disease

This is the only pneumococcal conjugate vaccine indicated for this specific population in the United States.

Patients must receive a primary pediatric pneumococcal vaccination series before receiving the pneumococcal conjugate vaccine.

The bacteria called "Streptococcus pneumoniae" are what cause pneumococcal disease. There are approximately 100 different types of this bacteria, called serotypes.

Capvaxine helps prevent pneumonia S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B.

Pneumococcal disease can be invasive or non-invasive. Examples of invasive disease are pneumococcal bacteremia (infection in the bloodstream), bacteremic pneumococcal pneumonia (pneumonia with bacteremia) and pneumococcal meningitis (infection of the coverings of the brain and spinal cord).

Non-invasive pneumococcal disease examples include pneumonia, which is when pneumococcal disease is confined to the lungs.

This approval is based on data from the phase 3 STRIDE-13 trial, which compared the effectiveness of Capvaxine to PPSV23 (pneumococcal 23-valent polysaccharide vaccine) in 874 patients, who were randomized 3:2 to receive a single Capvaxine dose (n=527) or PPSV23 (n=347).

Results show that Capvaxine was noninferior to PPSV23 for the 12 shared serotypes.

For the 9 serotypes that are unique to Capvaxine, Capvaxine produced meaningfully stronger antibody responses.

There's also a serotype called 15B that CAPVAXIVE doesn't directly target, but it triggered a useful immune response anyway because 15B is structurally similar to serotype 15C, which is in CAPVAXIVE's lineup.

Researchers performed a post-hoc analysis using the same noninferiority bar as the main comparisons and found CAPVAXIVE held up against PPSV23 for 15B too.

The safety profile of Capvaxine was comparable to PPSV23. Over the 6 months following vaccination, 5.5% of the Capvaxine group and 7.2% of the PPSV23 group experienced at least one serious adverse event.

Only one event across the whole study was judged by investigators to be caused by the vaccine: a single Capvaxine recipient fainted approximately 3 minutes after the shot, severe enough to require hospitalization (Grade 2 severity). Fainting shortly after vaccination is a known, generally non-serious phenomenon (often a vasovagal reaction to the injection itself rather than the vaccine's contents), though it was still serious enough in this case to need medical attention.

“Children and adolescents with certain chronic conditions are at an increased risk for pneumococcal disease, including pneumonia, meningitis and bloodstream infections,” Rotem Lapidot, M.D., Chief of Pediatric Infectious Diseases at Rambam Health Care Campus and STRIDE-13 trial investigator, said in the news release. “This approval recognizes the potential of Capvaxine to deliver additional protection by including serotypes not contained in approved primary pediatric PCV series and represents a new approach to helping protect children and adolescents at increased risk for pneumococcal disease.”