Poster Presentation 25th International Pathogenic Neisseria Conference 2026

Safety, effectiveness, and immunogenicity of meningococcal combined MenACWY-7B vaccine in healthy adolescents and adults: a randomized, controlled, partially blinded phase 1/2 study (#054)

Ugo D’Oro 1 , Lorenzo Argante 1 , Vikramjit Singh 1 , Isabelle Lechevin 2 , Sila Akhan 3 , Isabel Leroux-Roels 4 , Kanchanamala Withanage 5 , Priscila Wolff 6 , Maria Lattanzi 1 , Pavitra Keshavan 1
  1. GSK, Sienna, Italy
  2. GSK, Rixensart, Belgium
  3. Kocaeli University, Kocaeli, Turkey
  4. Center for Vaccinology, Ghent University and Ghent University Hospital, Ghent, Belgium
  5. Centre for the Evaluation of Vaccination, Antwerp, Belgium
  6. Instituto Brasil de Pesquisa Clínica, Rio de Janeiro, Brazil

Background: MenACWY-7B is a pentavalent meningococcal vaccine comprising antigenic components from established vaccines MenACWY-CRM and 4-component MenB (4CMenB), and 3 additional MenB antigen components.

 

Aim/Methods: This completed phase 1/2 study (NCT04886154) was designed to assess the safety, effectiveness, and immunogenicity of MenACWY-7B in healthy adults 18–40 years of age (phase 1) and healthy adolescents and adults 10–25 years of age (phase 2). Phase 2 participants were randomized to receive a formulation containing either a low (MenACWY-7B-low) or high dose (MenACWY-7B-high) of the novel antigen components as 2 vaccine doses given either 2 (0,2-month) or 6 months (0,6-month) apart, or control vaccines (MenACWY-CRM + 4CMenB). Effectiveness was evaluated using endogenous complement human serum bactericidal assay (hSBA) against 110 serogroup B invasive disease strains. Immunogenicity was measured with standard hSBA.

 

Results: Phase 1 (n=32) was completed without safety issues. In phase 2 (n=1052), both formulations and schedules of MenACWY-7B were well tolerated. Reactogenicity and safety profiles were similar to control vaccines, and no safety issues were identified. Both formulations and schedules demonstrated immunological non-inferiority against serogroups ACWY compared with MenACWY-CRM (two-sided 97.5% CI for the difference above -10% margin). Both formulations also showed higher MenB effectiveness compared with 4CMenB at a 0,6-month schedule; however, the predetermined superiority criterion was not met (two-sided 97.5% CI for the difference not above the prespecified +5% margin), as effectiveness in the control group was higher than expected. At a 0,6-month schedule, the percentage of participants with ≥90% serogroup B strains killed was 71.2% for MenACWY-7B-low, 70.7% for MenACWY-7B-high, and 52.3% for control. For both formulations (0,6-month schedule), the percentages of participants with a 4-fold rise in hSBA titers were comparable to 4CMenB control for the MenB antigens common to both vaccines, and were higher than control for the 3 novel antigens. Immune response for all MenB antigens was higher with the 0,6-month vs. 0,2-month schedule.

 

Conclusions: These results demonstrate the added value of the new antigen components in MenACWY-7B. An increase in the interval between MenACWY-7B vaccinations was associated with an increase in the effectiveness and immunological response of MenACWY-7B.

Funding: GSK.