Vaxcyte Advances to Second Stage of Ongoing Phase 2 Study Evaluating VAX-31 for the Prevention of Invasive Pneumococcal Disease in Infants

Core Insights - Vaxcyte has advanced to Stage 2 of the Phase 2 study for VAX-31, a 31-valent pneumococcal conjugate vaccine designed to prevent invasive pneumococcal disease in infants [1][2][3] - The company expects to announce topline safety, tolerability, and immunogenicity data from the primary immunization series in mid-2026, followed by booster dose data approximately nine months later [1][2] - VAX-31 aims to cover approximately 94% of invasive pneumococcal disease and 93% of acute otitis media in U.S. children under five [1][6] Company Overview - Vaxcyte is a clinical-stage vaccine innovation company focused on developing high-fidelity vaccines to combat bacterial diseases [2][8] - The company is also developing VAX-24, a 24-valent pneumococcal conjugate vaccine, which is currently in a Phase 2 infant study [8] - Vaxcyte's technology aims to provide broader coverage against both currently circulating and historically prevalent strains compared to standard-of-care pneumococcal conjugate vaccines [2][3] Study Details - The VAX-31 infant Phase 2 study is a randomized, double-blind, active-controlled, dose-finding study evaluating safety, tolerability, and immunogenicity compared to Prevnar 20 [4] - Stage 1 assessed safety and tolerability in 48 infants across three ascending dose levels, while Stage 2 will include approximately 750 infants [4][10] - The study design follows ACIP recommendations, with a primary immunization series consisting of three doses at two, four, and six months, followed by a booster at 12-15 months [4] Disease Context - Pneumococcal disease, caused by Streptococcus pneumoniae, leads to significant morbidity and mortality, particularly in children under five [5][6] - It is a leading cause of vaccine-preventable deaths globally and is associated with high hospitalization rates in the U.S. [5] - The need for broader-spectrum vaccines is underscored by the emergence of antibiotic-resistant strains of Streptococcus pneumoniae [5][6] Product Development - VAX-31 is positioned as the broadest-spectrum pneumococcal conjugate vaccine candidate in clinical development, with potential to increase coverage by 12-40% over current adult vaccines [6][7] - The vaccine is designed to provide protection against over 95% of invasive pneumococcal disease circulating in adults aged 50 and older [6] - Vaxcyte's innovative approach includes modern synthetic techniques for vaccine production, aiming to enhance immunological benefits [9]