Immunogenicity and safety of different schedules of the meningococcal ABCWY vaccine, with assessment of long-term antibody persistence and booster responses - results from two phase 2b randomized trials in adolescents.

The meningococcal serogroup B (MenB) protein vaccine, 4CMenB, combined with MenA, MenC, MenW and MenY polysaccharide-protein conjugates for a pentavalent MenABCWY vaccine, can potentially protect against most causative agents of invasive meningococcal disease worldwide. Two phase 2b, randomized, multicenter studies were conducted (NCT02212457, NCT02946385) to assess the immunogenicity and safety of the MenABCWY vaccine as well as antibody persistence and response to a booster dose 2 years after the last vaccination, compared to 4CMenB vaccination. Participants (10 - 18 years), randomized (3:3:2:2:2:2), received the 4-component 4CMenB vaccine according to a 0-2 month (M) schedule or MenABCWY according to a 0-2, 0-6, 0-2-6, 0-1, or 0-11 M schedule. All participants received 5 injections (at M0, M1, M2, M6 and M12) with either the study vaccines or placebo/hepatitis A vaccine. Follow-on participants (4CMenB-0-2, MenABCWY-0-2, MenABCWY-0-6 and MenABCWY-0-2-6 groups) received one dose of either 4CMenB (4CMenB-0-2 group) or MenABCWY and newly enrolled, age-matched, meningococcal vaccine-naïve adolescents (randomized 1:1) received 2 doses (0-2 M) of either 4CMenB or MenABCWY. MenABCWY vaccination was immunogenic against MenB test strains. Non-inferiority for all 4 components of the 4CMenB vaccine could not be demonstrated for the 0-2 M schedule. Antibodies persisted up to 2 years post-MenABCWY vaccination and a booster dose induced an anamnestic response as higher titers were observed in follow-on participants compared to the first-dose response in vaccine-naïve participants. MenABCWY had a clinically-acceptable safety profile, not different from that of 4CMenB.