1967. Study of the Immunogenicity and Safety of an Investigational Quadrivalent Meningococcal Conjugate Vaccine (MenACYW-TT) When Co-administered with Other Vaccines in Healthy Adolescents

BACKGROUND: The MenACYW-TT conjugate vaccine is a quadrivalent meningococcal vaccine candidate intended for global use in all age groups. This pivotal phase II study evaluated the safety and immunogenicity of the vaccine when compared with a licensed quadrivalent conjugated meningococcal vaccine (MCV4-CRM) when co-administered with tetanus, diphtheria, acellular pertussis (Tdap), and human papilloma virus (HPV4) vaccines in meningococcal vaccine naïve adolescents (10–17 years of age). METHODS: A randomized, open-label, multicenter study (NCT02199691) was conducted in 1,715 healthy subjects in the United States, who were randomly assigned to receive MenACYW-TT conjugate vaccine, MCV4-CRM, MenACYW-TT conjugate vaccine (co-administered with Tdap and HPV4), or Tdap and HPV4 vaccines. Serum bactericidal assay with human (hSBA) and baby rabbit (rSBA) complement was used to measure antibodies against serogroups A, C, W, and Y test strains at baseline and 30 days after vaccination. Safety data were collected up to 6 months post-vaccination. RESULTS: Noninferiority of immune response was demonstrated between MenACYW-TT conjugate vaccine and MCV4-CRM, and MenACYW-TT conjugate vaccine when co-administered with Tdap and HPV4 vaccines vs. when administered alone, based on percentages of study participants achieving hSBA vaccine seroresponse at Day 30 fromD0 baseline. The proportions of individuals with hSBA ≥ 1:8 after MenACYW-TT conjugate vaccine administration were higher than those after MCV4-CRM administration for all four serogroups (A: 93.5% vs. 82.8%; C: 98.5% vs. 76.0%; W: 99.1% vs. 90.7%; Y: 97.2% vs. 83.2%). Co-administration of MenACYW conjugate, Tdap and HPV4 vaccines did not generate any results suggestive of immune interference. Reactogenicity profiles were comparable across study groups. Most unsolicited adverse events were of Grade 1 or Grade 2 intensity. No vaccine related serious adverse events were reported. CONCLUSION: MenACYW-TT conjugate vaccine was immunogenic and well tolerated when administered as a single dose to meningococcal vaccine naïve adolescents along with Tdap and HPV4 vaccines. Such a vaccine will offer an alternative for the prevention of invasive meningococcal disease in susceptible populations across the world. DISCLOSURES: All authors: No reported disclosures.