Immunogenicity and Safety of a Quadrivalent Meningococcal Tetanus Toxoid-Conjugate Vaccine (MenACYW-TT) in Meningococcal Vaccine-Naïve Participants Across a Broad Age Range (2-55 years) in Japan: A Phase III Randomized Study.

MenACYW-TT is a quadrivalent meningococcal tetanus toxoid-conjugate vaccine designed to prevent invasive meningococcal disease. The primary objective of this study was to demonstrate non-inferiority of the vaccine seroresponse to a single dose of MenACYW-TT compared to a licensed Meningococcal quadrivalent diphtheria-conjugate vaccine, MCV4-DT. This Phase III double-blind, multi-center study was conducted in meningococcal vaccine-naive participants aged 2-55 years in Japan (NCT04368429; JapicCTI-205288). Participants were randomized 1:1 to MenACYW-TT (n=180) or MCV4-DT (n=180). Functional antibodies against meningococcal serogroups A, C, W, and Y were measured using a serum bactericidal antibody assay with human complement (hSBA) at baseline (D0) and 30 days after vaccination (D30). Seroresponse was defined as post-vaccination titers ≥1:16 for participants with baseline titers <1:8; or ≥4-fold increase for participants with baseline titers ≥1:8. Safety data were collected for 30 days. Non-inferiority of the vaccine seroresponse vs MCV4-DT was demonstrated at D30 for each serogroup (A: 85.6% vs. 65.4%; C: 96.6% vs. 62.6%; W: 87.4% vs. 49.2%; Y: 97.7% vs. 63.5%, respectively). MenACYW-TT was well-tolerated, with no safety concerns identified. In conclusion, when administered as a single dose, MenACYW-TT was well tolerated with a non-inferior immune response compared to MCV4-DT, providing a potential alternative vaccine for this population.