Vaxcyte Vaccine Holds Its Own Against Pfizer and Merck Shots

Vaxcyte's stock surged more than 57% in pre-market trading after its pneumococcal vaccine candidate, VAX-31, demonstrated strong results in a phase 3 study. The biotech compared VAX-31 against Pfizer's Prevnar 20 and Merck & Co.'s Capvaxive in the Opus-1 trial, which aimed to prevent invasive pneumococcal disease and pneumonia in adults.

VAX-31 met non-inferiority criteria for all 20 serotypes targeted by Prevnar 20 and 17 of the 19 serotypes targeted by Capvaxive. The non-inferiority was defined as a lower bound of the 95% confidence interval exceeding 0.667. For the remaining two serotypes, VAX-31 still passed a lower historical threshold of 0.5. The vaccine was also well tolerated, with a safety profile similar to the approved vaccines.

Vaxcyte CEO Grant Pickering highlighted that the positive results provide a strong clinical foundation for the FDA approval application, expected in the first half of 2028. The company's Chief Scientific Officer James Wassil noted that the comparison with Capvaxive could be a key focus for the FDA, as Capvaxive targets strains responsible for a larger share of pneumococcal disease in U.S. adults.

Vaxcyte's proprietary carrier-sparing technology allows for broader serotype coverage without compromising antibody responses. The biotech is conducting two additional phase 3 trials, Opus-2 and Opus-3, with readouts expected in early 2025, along with data from a phase 2 study in infants.