Vaxcyte Announces First Participants Dosed In OPUS Phase 3 Pivotal, Noninferiority Trial Evaluating VAX-31 For Prevention Of Invasive Pneumococcal Disease And Pneumonia In Adults

Trial Design Finalized in Consultation and Alignment with U.S. Food and Drug Administration 

Study Designed to Establish a New Standard for Adult Pneumococcal Conjugate Vaccines Through Head-to-Head Safety, Tolerability and Immunogenicity Comparisons of VAX-31 with Capvaxive (PCV21) and Prevnar 20 (PCV20), the Current Standards of Care

Company Expects to Report Topline Safety, Tolerability and Immunogenicity Data for OPUS Phase 3, Noninferiority Trial in the Fourth Quarter of 2026 and Initiate Additional Phase 3 Studies in 2026 with Readouts in 2027, Supporting Planned BLA Submission

VAX-31 is Designed to Cover ~95% of Invasive Pneumococcal Disease (IPD) and ~88% of Pneumococcal Pneumonia in U.S. Adults Aged 50+, with Potential to Provide an Incremental 14-34% Broader IPD Coverage and 19-31% Broader Pneumonia Coverage than Standard-of-Care Vaccines

VAX-31 Aims to Advance Adult Pneumococcal Protection by Maintaining Critical Pressure on Both Currently Circulating and Long-Established, Historically Disease-Causing Serotypes, While Maintaining or Improving Immune Responses

SAN CARLOS, Calif., Dec. 08, 2025 (GLOBE NEWSWIRE) -- Vaxcyte, Inc. (NASDAQ:PCVX), a clinical-stage vaccine innovation company, today announced that the first participants were dosed in the OPUS (OPA-based Pivotal U.S. Study) Phase 3 pivotal, noninferiority trial evaluating VAX-31 for the prevention of invasive pneumococcal disease (IPD) and pneumonia in adults. The design of the trial, which is expected to enroll approximately 4,000 participants, was finalized in consultation and alignment with the U.S. Food and Drug Administration (FDA). Topline safety, tolerability and immunogenicity results from the OPUS trial, which are expected to serve as the cornerstone of the VAX-31 Biologics License Application (BLA), are anticipated in the fourth quarter of 2026.

Building on the unprecedented results from the Company's VAX-31 adult Phase 1/2 study, which demonstrated both broader serotype coverage and stronger overall immune responses than Prevnar 20 (PCV20), the OPUS trial represents the next step in setting a new standard for adult pneumococcal vaccines. This trial is evaluating the safety, tolerability and immune responses of VAX-31 in adults aged 50 and older through direct, head-to-head comparisons with both Capvaxive (PCV21) and PCV20, the current standard-of-care pneumococcal conjugate vaccines (PCVs), with the objective of establishing a best-in-class profile for VAX-31.

The key primary immunogenicity objectives of the OPUS trial are to demonstrate 1) noninferiority if the lower bound of the two-sided 95% confidence interval (CI) for the opsonophagocytic activity (OPA) geometric mean ratio (GMR) of VAX-31 exceeds 0.667 compared with PCV21 and/or PCV20 for the 28 serotypes shared with one or both comparators and 2) superiority if the lower bound of the two-sided 95% CI of the OPA GMR exceeds 2.0 for the three serotypes unique to VAX-31 and serotype 20B versus the comparator vaccines. The trial is also evaluating the safety, tolerability and immune responses of VAX-31 in adults aged 18-49. Key secondary immunogenicity objectives are included to evaluate VAX-31 based on additional measures of noninferiority, superiority and statistically greater immune responses.