Vaxcyte shares jump as pneumococcal vaccine succeeds in late-stage trial

• VAX-31 produced immune responses comparable to Pfizer's Prevnar 20 and Merck's Capvaxive against 28 bacterial strains, with stronger responses against three unique strains and strain 20B
• The vaccine showed a consistent safety profile across age groups with no serious adverse events related to the vaccines
• Vaxcyte expects results from two additional late-stage trials in first half 2027 and plans to submit a US marketing application in first half 2028

Vaxcyte Pneumococcal Vaccine Succeeds in Late-Stage Trial

Vaxcyte announced Monday that its experimental pneumococcal vaccine, VAX-31, successfully met primary endpoints in a late-stage trial involving adults aged 50 and older, driving shares significantly higher.

Key Trial Results:

VAX-31 demonstrated immune responses at least comparable to Pfizer's Prevnar 20 and Merck's Capvaxive across 28 bacterial serotypes (strains). The vaccine showed superior immune responses against three strains unique to VAX-31 and against strain 20B. In separate comparisons against Prevnar 20, VAX-31 met efficacy benchmarks for all 20 overlapping strains in certain analyses, though two strains failed to meet criteria in other comparisons.

The vaccine maintained a consistent safety profile across all age groups studied, with no serious adverse events attributed to the vaccines.

Market Context:

Pneumococcal disease, caused by bacteria leading to pneumonia, meningitis, and bloodstream infections, poses particular risk to older adults. VAX-31 competes directly with established vaccines from industry giants Pfizer and Merck in this critical market segment.

Timeline and Implications:

Vaxcyte expects results from two additional late-stage trials in the first half of 2027 and plans to submit a U.S. marketing application in the first half of 2028. This positions the company for potential market entry by 2029, contingent on regulatory approval.

Investment Perspective:

The positive trial data validates Vaxcyte's approach and establishes VAX-31 as a credible competitor in the pneumococcal vaccine market. Success could challenge the duopoly held by Pfizer and Merck, though commercialization remains approximately two years away pending additional trial data and regulatory review.