P-1459. Utility of the Pentavalent MenABCWY Meningococcal Vaccine (PenbrayaTM) Within Alternative US Meningococcal Vaccination Schedules

Background The US meningococcal vaccination schedule – routine vaccination against serogroups A/C/W/Y (MenACWY) at ages 11‒12 and 16 years (y), a 2-dose MenB series based on shared clinical decision making (SCDM) at ages 16‒23 y, and endorsement of Pfizer’s MenABCWY vaccine (PenbrayaTM) when both vaccines are recommended, is being reevaluated. We assess how MenABCWY clinical data support alternative schedules being considered. Methods Alternative meningococcal vaccination schedules were based on materials from recent US Advisory Committee on Immunization Practices meetings. Pfizer’s MenABCWY clinical data were derived from 3 studies that collectively included > 4000 participants aged 10–25 y. Results New meningococcal vaccination schedules being considered as of June 2024 (Table 1) include routine or risk-based MenB vaccination due to implementation challenges and poor uptake associated with the existing SCDM recommendation. Pfizer’s MenABCWY vaccine was well tolerated for all schedules (0-, 6-mo; 0-, 12-mo; and 0-, 36-mo); there were no safety concerns. Immune responses were statistically noninferior for 1 MenABCWY dose compared with 1 MenACWY-CRM (Menveo®) dose regardless of previous MenACWY experience and for 2 MenABCWY doses using a 0-, 6-mo schedule compared with 2 MenB-fHbp (Trumenba®) doses. As currently recommended, a MenABCWY dose could replace MenACWY Dose 2 and MenB Dose 1 of proposed schedules both with (options 1, 2, 4) and without (options 3, 5) an earlier MenACWY dose. Compared to the 0-, 6-mo schedule, immune responses for the extended schedules with MenACWY remained robust, and for MenB were higher 1 and 24 months after the last MenABCWY dose suggesting a longer persistence of immune response. Findings support MenABCWY replacement of MenB Dose 2 for all schedule options, expanding serogroup coverage. Option 4 could be reduced to 2 MenABCWY doses at 15 and 17‒18 y, and assuming immune response remains robust for dosing intervals > 3 y, options 1 and 2 could be similarly adjusted. Conclusion MenABCWY use in place of separate MenACWY and MenB vaccinations within proposed schedules is supported by clinical data and will reduce the number of injections required, especially for 2-dose, extended-interval MenABCWY schedules spanning the period of elevated risk. Funded by Pfizer. Disclosures Jessica Presa, MD, Pfizer Inc: Industry|Pfizer Inc: Stocks/Bonds (Public Company) Steven Shen, MD, PhD, Pfizer Canada ULC: Industry Jamie Findlow, PhD, Pfizer Ltd: Industry|Pfizer Ltd: Stocks/Bonds (Public Company) Vincenza Snow, MD, Pfizer Inc: Industry Paul Palmer, PhD, Pfizer Inc: Employee|Pfizer Inc: Stocks/Bonds (Public Company)