The TLR-4 agonist adjuvant, GLA-SE, improves magnitude and quality of immune responses elicited by the ID93 tuberculosis vaccine: first-in-human trial

Abstract

Tuberculosis (TB) is the leading cause of infectious death worldwide. Development of improved TB vaccines that boost or replace BCG is a major global health goal. ID93 + GLA-SE is a fusion protein TB vaccine candidate combined with the Toll-like Receptor 4 agonist adjuvant, GLA-SE. We conducted a phase 1, randomized, double-blind, dose-escalation clinical trial to evaluate two dose levels of the ID93 antigen, administered intramuscularly alone or in combination with two dose levels of the GLA-SE adjuvant, in 60 BCG-naive, QuantiFERON-negative, healthy adults in the US (ClinicalTrials.gov identifier: NCT01599897). When administered as 3 injections, 28 days apart, all dose levels of ID93 alone and ID93 + GLA-SE demonstrated an acceptable safety profile. All regimens elicited vaccine-specific humoral and cellular responses. Compared with ID93 alone, vaccination with ID93 + GLA-SE elicited higher titers of ID93-specific antibodies, a preferential increase in IgG1 and IgG3 subclasses, and a multifaceted Fc-mediated effector function response. The addition of GLA-SE also enhanced the magnitude and polyfunctional cytokine profile of CD4+ T cells. The data demonstrate an acceptable safety profile and indicate that the GLA-SE adjuvant drives a functional humoral and T-helper 1 type cellular response.

Conflict of interest statement

S.G.R. is a founder of, and holds an equity interest in, Immune Design Corp., a licensee of certain rights associated with GLA. The remaining authors declare no competing interests.

Figures

Fig. 1

ID93 + GLA-SE elicited significantly higher ID93-specific total IgG antibody responses than those vaccinated with ID93 protein alone. a Magnitude of ID93-specific antibody responses for differing doses of antigen and/or adjuvant. Geometric mean titer and 95% confidence interval as determined by ELISA using serum collected on the days shown. Vaccinations were administered on Days 0, 28, and 56 (arrows) after blood collection. ID93 + GLA-SE elicited significantly higher ID93-specific total IgG antibody responses than those vaccinated with ID93 protein alone. Statistical significance between adjuvant containing regimens and protein alone regimens at each time point was evaluated by two-way ANOVA and Tukey’s multiple comparisons test with p-values indicated as: <0.05 (*), <0.01 (**), <0.0001 (***). b IgG subclass analysis of ID93-specific antibody responses for different antigen and adjuvant doses. Geometric mean titer and 95% confidence interval as determined by ELISA using serum collected at the days shown. Vaccinations were administered on Days 0, 28, and 56. Serum samples were collected on those days prior to study injections. Inclusion of the GLA-SE adjuvant elicited a preferential induction of IgG1 and IgG3 subclasses. c Component antigen specificity of antibody responses for individuals administered different antigen and adjuvant doses. Bar represents group geometric mean titer as determined by ELISA using serum collected at the days shown. Vaccinations were administered on Days 0, 28, and 56. Serum samples were collected on those days prior to study injections. Total IgG responses were measured against all four component antigens with Rv1813 being the highest

Fig. 2

Magnitude and specificity of antigen-specific T cell response. a Kinetics of ID93 antigen-specific CD4+ T cells measured from cryopreserved PBMC at baseline and 2 weeks after each vaccination. Median frequencies of CD4+ T cells positive for any antigen-specific marker (IFNγ, TNF, IL-2, CD154, IL-4/IL-22, and/or IL-17) as measured by intracellular cytokine staining of antigen (peptide pools)-stimulated PBMCs with unstimulated values subtracted. Error bars show 95% confidence intervals. Vaccinations were administered on Days 0, 28, and 56. b Frequencies of ID93-specific (defined as positive for CD154, IFNγ, TNF, and/or IL-2) for CD4+ and CD8+ T cell responses in individual subjects as measured by intracellular cytokine staining of ID93 protein-stimulated whole blood with unstimulated values subtracted. Vaccinations were administered on Days 0, 28, and 56

Fig. 3

T cell cytokine profiles from whole blood ICS for Cohorts 1 and 2. Frequencies of ID93-specific CD4 T cells co-expressing different cytokines are shown for Cohorts 1 and 2 as measured by intracellular cytokine staining of ID93-stimulated whole blood with unstimulated values subtracted. The bar shows the median frequency, the box shows the interquartile range, and the whiskers show the maximum and minimum values. Vaccinations were given on Days 0, 28, and 56. a Combined data for 2 μg and 10 μg ID93 recipients, b 2 μg ID93 + 2 μg GLA-SE, c 10 μg ID93 + 2 μg GLA-SE. Wilcoxon matched pairs signed rank test to compare frequencies of ID93-specific cytokine response between Day 0 and Day 42 timepoints. d Proportions of ID93-specific CD4 T cells co-expressing different cytokines are shown for Cohort 1 and 2 subjects administered 2 μg ID93, 10 μg ID93, 2 μg ID93 + 2 μg GLA-SE, or 10 μg ID93 + 2 μg GLA-SE as measured by intracellular cytokine staining of ID93-stimulated whole blood with unstimulated values subtracted. Results are shown for Day 70 (2 weeks post third vaccination). Due to low subject numbers, results for 2 μg ID93 and 10 μg ID93 were combined

Fig. 4

Vaccine induced antibody response profiles. a Heatmap shows changes in vaccine antigen-specific and control influenza hemagglutinin-specific antibody isotype titers after vaccination. Each row represents an individual. Each column represents an antibody isotype. The vaccine regimen is specified on the left with legend showing that red represents the top 5th percentile in the amount of change (large changes) and blue represents the 95th percentile in the amount of change (small changes). b Changes in ID93-specific antibody-dependent cellular cytotoxicity (ADCC) NK cell production of IFNγ, MIP1β, and CD107a, and antibody-dependent cellular phagocytosis (ADCP) are plotted. Each line represents each individual before (Day 0) and after (Day 84) vaccination and individuals are grouped by vaccine regimen. Statistical significance calculated by Wilcoxon matched pairs signed rank test is indicated (*p < 0.05, ***p < 0.001). c Spearman correlation coefficients between ID93 antibody-specific isotypes and ID93-specific antibody effector functions are depicted by bars with red denoting positive and blue denoting negative values. d Polyfunctionality as defined by total number of ID93-specific antibody effector functions (NK cell-mediated IFNγ, MIP1β, and CD107a, and antibody-dependent cellular phagocytosis) are graphed on a per individual basis. Each individual is represented by a dot, and individuals are grouped into vaccine regimens as noted (purple = ID93, green = ID93 + GLA-SE)

Fig. 5

Clinical trial CONSORT diagram for TBVPX-113. Flow chart shows the number of subjects entering the study from enrollment, allocation, and follow-up (FU). Subjects missing the second and third injection dose either withdrew consent or were lost to FU. Subjects were in FU for 1 year after the third injection. The Safety Population is defined as all subjects who received at least one study injection; the Per Protocol Population comprises subjects who received all three study injections and completed Day 84. All subjects received at least one study injection and were included in the analyses of safety and immunology