Vaxcyte, Inc. (Nasdaq: PCVX), a clinical-stage vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases, announced today that the first participants were dosed in the Phase 2 portion of its ongoing Phase 1/2 clinical study evaluating VAX-24 for the prevention of invasive pneumococcal disease (IPD) and pneumonia in adults.
The initiation of the Phase 2 portion of the study in healthy adults 50 to 64 years of age occurred after the independent Data Monitoring Committee completed a prespecified review of Phase 1 safety and tolerability data and recommended that the study progress as planned. The Company expects to announce topline safety, tolerability and immunogenicity results from both the Phase 1 and Phase 2 portions of the VAX-24 study by the end of 2022.
“Moving forward with the larger Phase 2 portion of the VAX-24 Phase 1/2 study is an exciting step toward delivering potential clinical proof-of-concept data for our lead, 24-valent PCV candidate,” said Grant Pickering, Chief Executive Officer and Co-founder of Vaxcyte. “We developed VAX-24 with the intent of improving upon the standard-of-care pneumococcal vaccines by delivering the broadest spectrum PCV and we look forward to announcing the topline safety, tolerability and immunogenicity results from both the Phase 1 and Phase 2 portions of this study by the end of this year.”
The VAX-24 Phase 1/2 clinical proof-of-concept study is a randomized, observer-blind, dose-finding, controlled study designed to evaluate the safety, tolerability and immunogenicity of VAX-24 in healthy adults (NCT05266456). The Phase 1 portion of the study is evaluating the safety and tolerability of a single injection of VAX-24 at three dose levels and compared to Prevnar 20™ in 64 healthy adults 18 to 49 years of age. The Phase 2 portion is evaluating the safety, tolerability and immunogenicity of a single injection of VAX-24 at three dose levels and compared to Prevnar 20™ in approximately 800 healthy adults 50 to 64 years of age.
The prespecified immunogenicity endpoints of the Phase 2 portion of the study include an assessment of the induction of antibody responses, using immunoglobulin G (IgG) and opsonophagocytic activity (OPA), at each of the three VAX-24 doses and compared to Prevnar 20™ and, for the additional four serotypes contained in VAX-24 and Pneumovax® 23 but not in Prevnar 20™, the four-fold rise in antibody titers. The study is being conducted at approximately 13 sites in the United States.
About Pneumococcal Disease
Pneumococcal disease (PD) is an infection caused by Streptococcus pneumoniae (pneumococcus) bacteria. It can result in IPD, including meningitis and bacteremia, and non-invasive PD, including pneumonia, otitis media and sinusitis. Despite universal vaccination for PD in infants and in many adults in the United States, the overall incidence of PD is substantial and is driven by emerging serotypes not covered by currently available vaccines.
In the United States, approximately 900,000 people get pneumococcal pneumonia each year, which is estimated to result in approximately 400,000 hospitalizations and 28,000 deaths. Pneumococci also cause over 50% of all cases of bacterial meningitis in the United States. Antibiotics are used to treat pneumococcal disease, but some strains of the bacteria have developed resistance to treatments. The morbidity and mortality due to pneumococcal disease are highly significant, particularly for young children and older adults, underscoring the need for a more broad-spectrum vaccine.
VAX-24 is an investigational 24-valent PCV candidate designed to prevent IPD and pneumonia, which can be most serious for infants, young children, older adults and those with immune deficiencies or certain chronic health conditions. The public health community continues to affirm the need for vaccines that offer broader protection to prevent IPD and pneumonia.
VAX-24 is intended to improve upon the standard-of-care PCV vaccines for both children and adults by covering the serotypes that are responsible for most of the residual pneumococcal disease currently in circulation. Vaxcyte aims to efficiently create and deliver high-fidelity, broad-spectrum vaccines, such as VAX-24, by using modern synthetic techniques, including advanced chemistry and the XpressCF™ cell-free protein synthesis platform. Vaxcyte is deploying this approach with VAX-24 in order to add more pneumococcal strains without compromising the overall immune response.