723b. Investigational Meningococcal ABCWY Vaccine is Effective against a Broad Panel of Serogroup B Invasive Disease Strains in US Adolescents: a Phase 2, Controlled, Randomized Study
Session: Poster Abstract Session: Vaccines: Adolescent HPV and Meningococcal
Thursday, October 27, 2016
Room: Poster Hall
  • IDWEEK poster 723b_JA Welsch.pdf (357.0 kB)
  • Background: GSK Vaccines has developed an investigational meningococcal vaccine against serogroups A, B, C, W and Y (MenABCWY). In previous studies MenABCWY induced a robust immune response against vaccine-specific antigens and had an acceptable safety profile. We evaluated the effectiveness of MenABCWY against a large epidemiologically representative panel of US endemic N meningitidis serogroup B invasive disease strains, in healthy adolescents 10–18 years of age (NCT02140762).

    Methods: In this phase 2b, observer-blind, multicenter study, 305 adolescents were enrolled and randomized (1:1) to receive either two doses of MenABCWY or Placebo/MenACWY at study months (M) 0 and 2. A total of 110 serogroup B strains were randomly selected from a systematically collected CDC repository of US invasive meningococcal disease isolates. Antibody levels against these strains were assessed using an endogenous complement human serum bactericidal assay (enc-hSBA), with measurements at baseline and 1 month after second vaccination (M3).

    Results: At baseline, the mean percentage of seronegative subjects (without bactericidal activity at 1:4 dilution) across all strains was 79.9% in the MenABCWY group and 79.6% in the Placebo/MenACWY group. At M3, the mean percentage of seronegative subjects declined to 25.2% in the MenABCWY group and remained similar (76.2%) in the Placebo/MenACWY group. Vaccine effectiveness (VE) at M3 was 67% (95%CI: 66–68). At baseline, most subjects in both groups had bactericidal antibodies against <20% of tested strains, with 5%-7% of subjects having antibodies against >50% of strains. At M3, 97% of subjects in the MenABCWY group were protected against >50% of tested strains and 59% were protected against >70% of strains; protection in the Placebo/MenACWY group was unchanged from baseline.

    Conclusion: This is the first study showing VE of MenABCWY against a broad panel of US serogroup B invasive disease strains in healthy adolescents using a direct serological assessment. The study results support previous estimates for breadth of coverage for endemic serogroup B strains using Meningococcal Antigen Typing System (D. Medini et al., 2015).

    Funding: GlaxoSmithKline Biologicals SA

    Jo Anne Welsch, PhD1, Shelly Senders, MD2, Randle Middleton, MD3, Paola Pedotti, PhD1, Linda Han, MD4, Peter Dull, MD4 and Igor Smolenov, MD5, (1)GlaxoSmithKline BV, Amsterdam, Netherlands, (2)Senders Pediatrics, South Euclid, OH, (3)Optimal Research LLC, Huntsville, AL, (4)Novartis Vaccines and Diagnostics Inc, Cambridge, MA, (5)Novartis Vaccines, Amsterdam, Netherlands


    J. A. Welsch, GSK group of companies: Employee , Salary
    Novartis Vaccines (now a GSK company): former employee , Salary

    S. Senders, None

    R. Middleton, None

    P. Pedotti, GSK group of companies: Employee , Salary
    Novartis Vaccines (now a GSK company): former employee , Salary

    L. Han, Novartis Vaccines (now a GSK company): former employee and Shareholder , Salary and stocks

    P. Dull, Novartis Vaccines (now a GSK company): former employee , Salary

    I. Smolenov, Novartis Vaccines (now a GSK company): former employee , Salary

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.