After scoring approval as the world’s first pneumococcal disease vaccine made specifically for adults earlier this month, Merck’s Capvaxive passed the next test in its bid to take on Pfizer and its dominant Prevnar franchise.
At a meeting this week, the CDC's Advisory Committee on Immunization Practices (ACIP) gave a unanimous vote, with one abstention, in favor of the vaccine in millions of adults. Specifically, the vaccine experts recommended the shot for adults 65 and older who have not yet received a pneumococcal conjugate vaccine, plus for those 19 to 64 with certain underlying medical conditions or other risk factors.
Adults 19 years old and up who have started their pneumococcal vaccine series with Pfizer’s Prevnar 13 but have not received all of the recommended Merck’s Pneumovax 23 doses are also included in ACIP’s endorsement.
“The ACIP vote recognizes the clinical profile of Capvaxive for adults in the U.S., and we look forward to the CDC’s final, published recommendations,” Merck’s chief medical officer Eliav Barr, M.D., said in a press release.
Capvaxive protects against 21 serotypes of the bacterial infection that comprise 84% of the pneumococcal disease contracted by adults 50 and older, according to epidemiologic data from the CDC. Pfizer’s leading pneumococcal disease vaccine, Prevnar 20, protects against 20 serotypes that comprise 52% of the disease in that population.
While that differentiated disease coverage “will be compelling” to purchasers and prescribers, Merck still has work to do to surpass Pfizer’s offering, analysts at Leerink wrote in a note to clients. Prevnar’s equivalent recommendation puts the two “on equal terms," the analysts said.
Following much debate at the meeting, ACIP delayed a vote on recommending Capvaxive for all adults ages 50 to 64 to its next meeting in October, opting for further analysis before making the call. Leerink analysts expect the committee to ultimately lower the recommended age to 50 and recommend both Capvaxive and Prevnar 20, once again putting the two on an even playing field.
Meanwhile, Vaxcyte is working on another candidate for the disease that could shake up things up with the broadest serotype coverage as a 24-valent shot, the Leerink team noted. The company hopes to produce results from its phase 1/2 study in the third quarter and share its data with the ACIP group ahead of the October meeting, according to the analysts.
Merck’s adult-specific vaccine joins its 15-valent pneumococcal shot Vaxneuvance, which generated $665 million in sales last year. Pfizer’s Prevnar, meanwhile, pulled in revenue of $6.4 billion in 2023.