Investigational Meningococcal ABCWY Vaccines Effective in Adolescents, Young Adults

PHILADELPHIA, PA—Two investigational formulations of meningococcal MenABCWY vaccines have shown comparable immunogenicity to the licensed vaccines (MenACWY-CRM) and serogroup B (4CMenB), and the full outer membrane vesicle formulation gave higher GMT responses against B test strains, reported Stanley L. Block, MD, of the Kentucky Pediatric and Adult Research Center, Bardstown, KY, at IDWeek 2014.

The primary objectives of the Phase II observer-blind, controlled, randomized study were to assess noninferiority of 2 investigational formulations of MenABCWY vaccines compared to the licensed ACWY vaccine, and formulation selection based on a desirability index (DI).

The study enrolled 480 healthy 10-25 year-olds at 8 sites in the U.S. and 5 sites in Poland, between August 2011 and September 2012. Patients were excluded if they had previous meningococcal vaccination or known contact with confirmed meningococcal infection, as well as illness or infection within 3 days of study start, chronic illness, or known immune system impairment.

Subjects were randomized equally to four groups, and received 2 doses, 2 months apart, of either: MenABCWY+ outer membrane vesicle, MenABCWY+1/4 outer membrane vesicle, 4CMenB, or Placebo/MenACWY (MenACWY is given as a single dose, so a placebo saline injection was given at the first vaccination). The formulations of MenABCWY contained the recombinant proteins (rMenB) from 4CMenB and either ¼ or 1 full dose of outer membrane vesicle used in 4CMenB.

Antibodies against serogroups A, C, W, Y and B test strains were measured at baseline and 30 days after dose 2 using a serum bactericidal assay with human complement (hSBA). A DI based on immunogenicity (post-vaccine hSBA GMT ratios) and reactogenicity parameters were also compared for MenABCWY vaccines.

Two dose formulations of either MenABCWY formulation (full or ¼ outer membrane vesicle) resulted in significantly higher seroresponses to A, A, W and Y, than a single dose of MenACWY (90/92% vs. 73% for A; 95/93% vs. 63% for C; 80/84% vs. 65% for W; and 92/90% vs. 75% for Y). Robust immune responses against serogroup B test strains were induced by both MenABCWY vaccines, and comparable with 4CMenB

DI analyses were comparable among the 3 serogroup B-containing formulations, but the full dose outer membrane vesicle vaccine formulation induced higher GMTs than the 1/4 dose formulation against most serogroup B test strains. 

No vaccine related serious adverse events were reported, and reactogenicity profiles were similar between MenABCWT vaccines and 4CMenB.