Vaxcyte Inc. (NASDAQ:PCVX) is having one of those Mondays that biotech investors dream about. The stock is surging after the company dropped positive topline results from its pivotal Phase 3 OPUS-1 trial evaluating VAX-31, an investigational 31-valent pneumococcal conjugate vaccine.
The trial assessed the safety, tolerability, and immunogenicity of the candidate in adults, with the goal of preventing invasive pneumococcal disease and pneumococcal pneumonia. Those findings will form the foundation for an upcoming Biologics License Application submission to the U.S. Food and Drug Administration.
Primary Immunogenicity Endpoints Met
In the OPUS-1 trial, VAX-31 achieved all prespecified co-primary immunogenicity endpoints in participants aged 50 and older.
The vaccine candidate met noninferiority criteria across all 28 serotypes shared with existing vaccines Pfizer Inc.'s (NYSE:PFE) Prevnar 20 (PCV20) and/or Merck & Co Inc.'s (NYSE:MRK) Capvaxive (PCV21).
Specifically, VAX-31 matched noninferiority standards for 11 serotypes common to both PCV20 and PCV21 based on opsonophagocytic activity geometric mean ratios.
Furthermore, the candidate met noninferiority benchmarks for nine serotypes shared exclusively with PCV20 and eight serotypes shared solely with PCV21.
For the three unique serotypes alongside the cross-reactive serotype 20B, VAX-31 demonstrated superiority over the comparative vaccines.
Strong Immunobridging And Safety Profile
The trial also evaluated immunobridging in adults aged 18 to 49 compared to adults aged 50 to 64. VAX-31 met noninferiority criteria across all 321 serotype comparisons within this group.
Individual comparator analyses showed VAX-31 met noninferiority for 20 of 20 serotypes shared with PCV20 and 17 of 19 shared with PCV21, with serotypes 3 and 12F meeting historical threshold limits.
Safety evaluations confirmed that VAX-31 showed strong tolerability with a profile comparable to PCV20 and PCV21 across all tested age groups.
Solicited local and systemic reactions remained mostly mild-to-moderate, with most resolving within 48 hours.
Researchers recorded no vaccine-related serious adverse events or trial discontinuations due to adverse effects.
Future Clinical Pipeline Milestones
Looking ahead, the company plans to report data from the OPUS-2 and OPUS-3 adult Phase 3 trials in the first half of 2027.
Additionally, management expects Phase 2 trial results for infant indications by the end of the first half of 2027.
PCVX Price Action: Vaxcyte shares were up 56.91% at $88.62 during premarket trading on Monday. The stock is trading at a new 52-week high, according to market data.
