Immunogenicity and safety of a novel recombinant protective antigen anthrax vaccine (GC1109), a randomized, single-blind, placebo controlled phase II clinical study

Vaccine. 2019 Jun 27;37(29):3820-3824. doi: 10.1016/j.vaccine.2019.05.057. Epub 2019 May 28.

Abstract

Background: The demand on effective and safe anthrax vaccine is increasing as a part of the preparedness for possible bioterrorism in the future. We performed a randomized, single-blind, placebo controlled phase II clinical study to evaluate the immunogenicity and safety of a novel recombinant protective antigen (rPA) anthrax vaccine, GC1109, in healthy adult volunteers.

Methods: Participants were randomized to experiment groups (0.3 mL, 0.5 mL, and 1.0 mL of GC1109) or placebo group (normal saline 0.5 mL) in 2:2:2:1 ratio. They received respective vaccines intramuscularly at 0, 4 and 8 weeks. Immunogenicity was evaluated by seroconversion rate and geometric mean titer (GMT) of lethal toxin neutralizing assay (TNA) and anti-PA IgG by ELISA. Safety was assessed by laboratory tests, and solicited and unsolicited adverse events on diary cards.

Results: 30, 29, 30 participants were randomized to 0.3, 0.5, and 1.0 mL of GC1109 groups, respectively, while 15 to placebo group. 92 participants received all three doses. In per-protocol analysis, TNA GMTs at week 12 were 296.5, 285.2, and 433.2 in the three groups, respectively. Seroconversion rates measured by ELISA were 100% at week 12 in the three groups. Local and systemic vaccine-related adverse events were frequent; however, most of them were mild, and no serious events were observed.

Conclusions: A new rPA anthrax vaccine GC1109 was immunogenic after three doses of intramuscular administration, and was well-tolerated.

Keywords: Bacillus anthracis; Immunogenicity; Recombinant protective antigen anthrax vaccine; Safety.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anthrax / prevention & control
  • Anthrax Vaccines / adverse effects
  • Anthrax Vaccines / genetics
  • Anthrax Vaccines / immunology*
  • Antibodies, Bacterial / blood
  • Antigens, Bacterial / genetics
  • Antigens, Bacterial / immunology*
  • Bacterial Toxins / genetics
  • Bacterial Toxins / immunology*
  • Dose-Response Relationship, Drug
  • Female
  • Healthy Volunteers
  • Humans
  • Immunogenicity, Vaccine*
  • Injections, Intramuscular
  • Male
  • Middle Aged
  • Recombinant Proteins / immunology*
  • Seroconversion
  • Single-Blind Method
  • Vaccines, Synthetic / immunology
  • Young Adult

Substances

  • Anthrax Vaccines
  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Toxins
  • Recombinant Proteins
  • Vaccines, Synthetic
  • anthrax toxin