Immunogenicity, safety and inter-lot consistency of a meningococcal conjugate vaccine (MenACYW-TT) in adolescents and adults: A Phase III randomized study.

ABSTRACT

BACKGROUND: MenACYW-TT is an investigational quadrivalent (serogroups A, C, W and Y) meningococcal conjugate vaccine that is being developed for protection against invasive meningococcal disease. METHODS: In this Phase 3, blinded, randomized study, 3344 meningococcal vaccine-naïve 10-55-year-olds were randomized (3332) to receive one of three lots of MenACYW-TT or licensed quadrivalent meningococcal conjugate vaccine, MCV4-DT (NCT02842853). Antibody titers were assessed by human and rabbit complement serum bactericidal antibody assays. The co-primary objectives were to demonstrate lot-to-lot consistency of MenACYW-TT by the between-lot geometric mean titer ratios (GMTR) at Day 30, and non-inferiority of Day 30 vaccine seroresponses (titers ≥ 116 if pre-vaccination titers < 18, or ≥ 4-fold increase if pre-vaccination titers ≥ 18) with MenACYW-TT vs MCV4-DT. Further objectives included safety and immunogenicity. RESULTS: Lot consistency was demonstrated for all three lots, with GMTRs ranging from 0.87 to 1.1. The proportion of participants achieving seroresponse in the MenACYW-TT group (data pooled from the 3 lots) was non-inferior to MCV4-DT (A 74% vs 55%; C 89% vs 48%; W 80% vs 61%; Y 91% vs 73%, respectively). MenACYW-TT and MCV4-DT had similar safety profiles; no safety concerns were identified. CONCLUSIONS: The study met both co-primary endpoints, demonstrating lot-to-lot consistency and non-inferiority of MenACYW-TT vs MCV4-DT in adolescents and adults.