Vaxcyte Surges 50% After VAX-31 Hits All Phase 3 Goals, Launches $1 Billion Capital Raise

Vaxcyte shares surged roughly 50% on October 5 after its 31-valent pneumococcal conjugate vaccine candidate, VAX-31, met all prespecified primary endpoints in OPUS-1, the pivotal adult Phase 3 trial. The vaccine achieved noninferiority across all 28 serotypes it shares with Pfizer's Prevnar 20 (PCV20) and Merck's Capvaxive (PCV21) in adults aged 50 and older, and demonstrated superiority on three novel serotypes as well as serotype 20B. Safety was described as similar to both comparators, and the vaccine was well tolerated across age groups.

Two serotypes narrowly missed the greater-than-0.667 non-inferiority margin against PCV21, though both cleared the standard greater-than-0.5 threshold, a nuance analysts noted but did not view as a material setback, with some calling the overall result near best case. The broader 31-serotype coverage positions VAX-31 as a potentially differentiated option against established competitors in the pneumococcal vaccine market.

Vaxcyte said results from two additional adult Phase 3 trials, OPUS-2 and OPUS-3, are expected in the first half of 2027, with a U.S. Biologics License Application submission planned for the first half of 2028. Later on the same day, the company announced proposed public offerings totaling up to $1.15 billion: a $500 million offering of common stock and pre-funded warrants, a $500 million offering of convertible senior notes due 2032, and $150 million in combined over-allotment options across both legs.