Core Insights - Vaxcyte, Inc. announced positive topline results from its Phase 2 dose-finding study for VAX-24, a 24-valent pneumococcal conjugate vaccine (PCV) candidate, demonstrating safety and immunogenicity comparable to Prevnar 20® (PCV20) in healthy infants [2][3][4] Group 1: VAX-24 Study Results - VAX-24 was well-tolerated across all evaluated doses, with a safety profile similar to PCV20, and no serious adverse events related to the vaccine were reported [3][4] - Substantial immune responses were elicited post-primary three-dose immunization series, with robust IgG and opsonophagocytic assay (OPA) responses observed across all doses [4][5] - The mid dose of VAX-24 (2.2 mcg) was selected for further development based on its ability to meet non-inferiority criteria and generate robust immune responses [5][6] Group 2: Future Development Plans - The company plans to advance VAX-24 to a potential Phase 3 program, pending topline data from the VAX-31 Phase 2 study expected in mid-2026 [2][6] - Vaxcyte is also introducing VAX-XL, a third-generation PCV candidate aimed at expanding the spectrum of coverage against pneumococcal disease [2][6] - Key milestones include the initiation of a Phase 3 infant program with either VAX-24 or VAX-31 and the announcement of additional data from ongoing studies [8][10][11] Group 3: Study Design and Participant Information - The VAX-24 Phase 2 study is a randomized, observer-blind, dose-finding study involving 802 healthy infants, assessing safety, tolerability, and immunogenicity [7][9] - The study design includes a primary immunization series of three doses followed by a booster dose, with ongoing evaluations of immunogenicity and safety [9][10] Group 4: Industry Context - Pneumococcal disease remains a significant health threat, particularly in children under five, with Streptococcus pneumoniae being a leading cause of vaccine-preventable deaths globally [14][15] - The development of broader-spectrum vaccines like VAX-24 and VAX-31 is critical to addressing the substantial burden of invasive pneumococcal disease [6][14]