Vaxcyte's Next-Generation VAX-31 Pneumococcal Vaccine Tracks Toward Regulatory Milestone with Expanded Clinical Programs

Vaxcyte, Inc. (PCVX) is pushing forward with an ambitious development strategy for VAX-31, its next-generation 31-valent pneumococcal conjugate vaccine candidate. The company is simultaneously advancing parallel clinical programs in both adult and infant populations, with a clear track record of progress toward a planned Biologics License Application (BLA) submission. This multi-pronged approach represents a significant shift in pneumococcal vaccine protection, addressing a critical gap in current immunization options.

Breaking the 31-Valent Barrier: Why This Next-Generation Vaccine Matters

The development of VAX-31 comes at a crucial moment for global health. Pneumococcal disease remains a formidable challenge, causing serious invasive infections including meningitis and bacteremia, alongside common but debilitating conditions like pneumonia and otitis media. Older adults and young children face disproportionate risk from these infections, and the rising tide of antibiotic resistance has intensified the urgency for broader, more durable vaccine protection.

VAX-31 is fundamentally different from currently available pneumococcal vaccines. As a 31-valent conjugate vaccine, it expands coverage against both actively circulating and historically prevalent pneumococcal serotypes—a design that positions it as the broadest-spectrum option in clinical development today. According to Vaxcyte’s projections, this expanded coverage would protect approximately 95% of invasive pneumococcal disease (IPD) cases and 88% of pneumococcal pneumonia in U.S. adults aged 50 and older. For infants, the vaccine is designed to cover roughly 92% of IPD cases and 96% of acute otitis media incidents, demonstrating its potential across the entire at-risk population spectrum.

Dual Clinical Pathways: Accelerating VAX-31 Development in Adults and Infants

Vaxcyte is executing a sophisticated clinical strategy with distinct programs targeting different demographics. This parallel-track approach is designed to generate comprehensive safety and efficacy data while maintaining momentum toward regulatory approval.

The adult program has already begun recruitment. The company has dosed the first cohort in OPUS-2, a Phase 3 trial designed to evaluate VAX-31 when administered simultaneously with a seasonal influenza vaccine in pneumococcal-naïve adults aged 50 and older. This pragmatic trial design, expected to enroll approximately 1,300 participants across U.S. sites, will assess critical endpoints including safety, tolerability, and immunogenicity.

Additionally, Vaxcyte has announced plans to initiate OPUS-3 in the first quarter of 2026—a second Phase 3 study focused on adults who have previously received pneumococcal vaccines such as PPSV23 or PCV20. This study addresses an important clinical question: how does VAX-31 perform in previously vaccinated populations? Meanwhile, OPUS-1, the pivotal Phase 3 noninferiority trial evaluating VAX-31’s ability to prevent both IPD and pneumonia, continues active enrollment among adult participants.

The clinical data timeline reveals the company’s momentum: OPUS-1 is expected to deliver topline results in the fourth quarter of 2026, with OPUS-2 and OPUS-3 results anticipated in the first half of 2027. This staggered reporting schedule will provide sequential evidence to support regulatory discussions.

Infant Program on Track: Phase 2 Completion Sets Stage for Pivotal Trials

The infant clinical program has reached a significant milestone. Vaxcyte has completed enrollment in its Phase 2 dose-finding study, which evaluated VAX-31 in healthy infants using a three-dose primary series (administered at two, four, and six months of age) followed by a booster dose at 12-15 months. The scale of this study demonstrates the company’s commitment: more than 900 infants have been enrolled, with all participants having received at least their initial dose.

Topline safety, tolerability, and immunogenicity data from both the primary immunization series and booster dose are expected by the end of the first half of 2027, either as sequential releases or combined findings. This data will be crucial for determining the optimal dosing regimen and establishing safety parameters for potential subsequent pivotal trials.

Manufacturing Strategy: Building Infrastructure for Commercial Success

Beyond clinical development, Vaxcyte is laying the groundwork for manufacturing success. As part of a comprehensive U.S.-based manufacturing strategy, the company plans to begin construction of a custom fill-finish production line in North Carolina in the first quarter of 2026. This infrastructure investment is tied to Vaxcyte’s previously announced commitment to invest up to $1 billion in domestic manufacturing and related services—a substantial allocation that reflects confidence in VAX-31’s market potential.

The company has also established a dedicated operational presence in North Carolina to support chemistry, manufacturing, and controls (CMC) activities. This strategic positioning creates a streamlined pathway from clinical development to commercial-scale production, positioning Vaxcyte to rapidly scale manufacturing capacity once regulatory approval is achieved.

Looking Ahead: Next-Generation Track Toward Market

With OPUS-1 data expected in late 2026 and adult and infant program results flowing throughout 2027, Vaxcyte’s VAX-31 is tracking along a clearly defined path toward BLA submission. The combination of robust clinical progress, expanded manufacturing capacity, and a comprehensive regulatory strategy demonstrates the company’s serious commitment to bringing this next-generation pneumococcal vaccine to market. For healthcare providers and patients awaiting broader protection against pneumococcal disease, VAX-31 represents a significant advancement in preventive medicine—one that could redefine the standard of care for pneumococcal immunization across multiple age groups.