P-608. Clinical Profile of GSK's Pentavalent Meningococcal ABCWY Vaccine: An Overview

Abstract Background GSK’s MenABCWY vaccine was developed to provide broad protection against invasive meningococcal disease by combining the antigenic components of the licensed 4-component meningococcal serogroup B vaccine (MenB-4C) and serogroups A,C,W,Y vaccine (MenACWY-CRM). Methods An overview of the MenABCWY vaccine’s profile was derived from its clinical development program of 12 controlled studies,1-10 which enrolled over 7000 adolescents and adults in 13 countries. Results For serogroup B (MenB), non-inferiority of MenABCWY (2 doses, 6 months apart) to MenB-4C (2 doses, 2 months apart) was demonstrated in a phase 3 study9 in terms of vaccine-induced bactericidal immune responses measured by endogenous complement human serum bactericidal antibody (enc-hSBA) assay. The enc-hSBA assay uses each vaccinee’s serum as source of complement and tests a panel of 110 MenB strains representing 95% of disease-causing isolates in the US and ∼89% of global circulating strains,11 and is thereby used to assess immunological vaccine effectiveness (iVE) in clinical studies, in conditions close to real-world settings. MenABCWY iVE was 78% (95% CI: 77–79) against the panel of 110 MenB strains; serum from 84% of participants killed ≥ 70% of strains.9 For serogroups A,C,W,Y, non-inferiority of MenABCWY (2 doses, 6 months apart) to MenACWY-CRM (1 dose) was demonstrated in phase 3 studies in MenACWY-primed10 and -naïve9 participants, with robust immune responses against each serogroup.9,10 Phase 2 data for all 5 serogroups show 2-year and 4-year antibody persistence5,8 and anamnestic booster responses2,5,8 at 2 years after primary MenABCWY vaccination, and similar immune responses with MenABCWY 0-6 and 0-11 months schedules.8 In phase 3, 1 MenABCWY dose was non-inferior to 1 MenACWY-CRM dose as booster in participants primed with MenACWY ≥ 4 years previously.10 The safety and reactogenicity profile of MenABCWY was favorable overall and consistent with that of MenB-4C.1-3,8,9 Conclusion GSK’s combined MenABCWY vaccine is immunogenic, with demonstrated non-inferiority to MenB-4C and MenACWY-CRM vaccines, and a safety profile similar to that of MenB-4C. FUNDING: GSK Disclosures Daniela Toneatto, MD, GSK: Employee|GSK: Stocks/Bonds (Public Company) Maria Lattanzi, MD, PhD, GSK: Employee|GSK: Stocks/Bonds (Private Company) Ellen Ypma, Msc, GSK: Employee Karen O’Brien, PhD, GSK: Employee Steven Rubin, PhD, GSK: Employee Laura Tomasi Cont, PhD, GSK: Employee|GSK: Stocks/Bonds (Private Company) Paola Pedotti, PhD, GSK: Employee|GSK: Stocks/Bonds (Private Company) Woo-Yun Sohn, MD, GSK: Employed by GSK|GSK: Stocks/Bonds (Private Company)