Vaxcyte Announces Positive Results For Pneumococcal Vaccine

Vaxcyte is a company developing vaccines to combat bacterial diseases. Its pipeline includes conjugate and protein vaccines for preventing and treating infectious diseases.

Image credits: Vaxcyte

Vaxcyte, Inc has announced positive topline results from its Phase 1/2 study of VAX-31, a 31-valent pneumococcal conjugate vaccine (PCV) candidate. The study, which involved 1,015 adults aged 50 and older, found that VAX-31 was well tolerated and elicited strong opsonophagocytic activity (OPA) immune responses for all 31 serotypes evaluated. Notably, VAX-31 met or exceeded regulatory immunogenicity standards for all 31 serotypes at middle and high doses, showing significant improvements over Prevnar 20 (PCV20) for several serotypes.

“We are exceptionally proud to share these results, which we believe validate VAX-31’s potential as a best-in-class pneumococcal vaccine capable of raising the bar for immunogenicity standards,” said Jim Wassil, Executive Vice President and Chief Operating Officer of Vaxcyte. “The public health community continues to highlight the need for broader-protection vaccines to prevent IPD, which is associated with high case-fatality rates, antibiotic resistance and meningitis. To address this need, VAX-31 was designed to increase coverage to more than 95% of IPD circulating in adults 50 and older in the United States, with the potential to provide significantly greater coverage relative to today’s standard-of-care adult PCVs.”¹

Main Takeaways

Vaxcyte’s VAX-31 vaccine showed strong immune responses and was well tolerated in a Phase 1/2 study of 1,015 adults aged 50 and older.
VAX-31 met or exceeded immunogenicity standards for all 31 serotypes and demonstrated superior responses compared to Prevnar 20 for several serotypes.
Vaxcyte plans to advance VAX-31 to a Phase 3 trial by mid-2025 and initiate a Phase 2 infant study to offer broader protection against pneumococcal disease.

The randomized, observer-blind, dose-finding study compared three dosage levels of VAX-31 to PCV20, assessing its safety, tolerability, and immunogenicity over six months. Results showed that VAX-31 at the high and middle doses met non-inferiority criteria for all 20 common serotypes with PCV20, and demonstrated statistically superior immune responses for several serotypes. The vaccine also met superiority criteria for 11 additional serotypes unique to VAX-31.

Back in February, Vaxcyte completed enrollment for the Phase 1/2 trial of VAX-31, a 31-valent PCV designed to prevent invasive pneumococcal disease (IPD). The randomized, observer-blind, dose-finding study, which involves 1,015 participants, is evaluating three dosage levels of VAX-31 compared to PCV20.

Streptococcus pneumoniae causes PD, leads to severe infections such as meningitis, bacteremia, and pneumonia. It results in around 150,000 hospitalizations annually in the US The World Health Organization and the CDC classify Streptococcus pneumoniae as a top antibiotic-resistant threat. It is a leading cause of vaccine-preventable deaths in children under five and causes over 50% of bacterial meningitis cases in the US The emergence of antibiotic-resistant strains highlights the urgent need for a more effective vaccine.

Looking ahead, Vaxcyte plans to advance VAX-31 into a Phase 3 program, with a pivotal non-inferiority study set to begin by mid-2025. Additionally, a Phase 2 study of VAX-31 in infants is planned for early 2025. VAX-31 aims to provide broader protection against pneumococcal disease, potentially covering more than 95% of invasive pneumococcal disease (IPD) strains in adults. As a novel 31-valent PCV, it represents a significant advancement in pneumococcal vaccination, seeking to enhance coverage and efficacy beyond current standard vaccines.

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