Safety and immunogenicity of Ebola virus and Marburg virus glycoprotein DNA vaccines assessed separately and concomitantly in healthy Ugandan adults: a phase 1b, randomised, double-blind, placebo-controlled clinical trial.

BACKGROUND: Ebola virus and Marburg virus cause serious disease outbreaks with high case fatality rates. We aimed to assess the safety and immunogenicity of two investigational DNA vaccines, one (EBO vaccine) encoding Ebola virus Zaire and Sudan glycoproteins and one (MAR) encoding Marburg virus glycoprotein. METHODS: RV 247 was a phase 1b, double-blinded, randomised, placebo-controlled clinical trial in Kampala, Uganda to examine the safety and immunogenicity of the EBO and MAR vaccines given individually and concomitantly. Healthy adult volunteers aged 18-50 years were randomly assigned (5:1) to receive three injections of vaccine or placebo at weeks 0, 4, and 8, with vaccine allocations divided equally between three active vaccine groups: EBO vaccine only, MAR vaccine only, and both vaccines. The primary study objective was to investigate the safety and tolerability of the vaccines, as assessed by local and systemic reactogenicity and adverse events. We also assessed immunogenicity on the basis of antibody responses (ELISA) and T-cell responses (ELISpot and intracellular cytokine staining assays) 4 weeks after the third injection. Participants and investigators were masked to group assignment. Analysis was based on the intention-to-treat principle. This trial is registered at ClinicalTrials.gov, number NCT00997607. FINDINGS: 108 participants were enrolled into the study between Nov 2, 2009, and April 15, 2010. All 108 participants received at least one study injection (including 100 who completed the injection schedule) and were included in safety and tolerability analyses; 107 for whom data were available were included in the immunogenicity analyses. Study injections were well tolerated, with no significant differences in local or systemic reactions between groups. The vaccines elicited antibody and T-cell responses specific to the glycoproteins received and we detected no differences between the separate and concomitant use of the two vaccines. 17 of 30 (57%, 95% CI 37-75) participants in the EBO vaccine group had an antibody response to the Ebola Zaire glycoprotein, as did 14 of 30 (47%, 28-66) in the group that received both vaccines. 15 of 30 (50%, 31-69) participants in the EBO vaccine group had an antibody response to the Ebola Sudan glycoprotein, as did 15 of 30 (50%, 31-69) in the group that received both vaccines. Nine of 29 (31%, 15-51) participants in the MAR vaccine groups had an antibody response to the Marburg glycoprotein, as did seven of 30 (23%, 10-42) in the group that received both vaccines. 19 of 30 (63%, 44-80) participants in the EBO vaccine group had a T-cell response to the Ebola Zaire glycoprotein, as did 10 of 30 (33%, 17-53) in the group that received both vaccines. 13 of 30 (43%, 25-63) participants in the EBO vaccine group had a T-cell response to the Ebola Sudan glycoprotein, as did 10 of 30 (33%, 17-53) in the group that received both vaccines. 15 of 29 (52%, 33-71) participants in the MAR vaccine group had a T-cell response to the Marburg glycoprotein, as did 13 of 30 (43%, 25-63) in the group that received both vaccines. INTERPRETATION: This study is the first Ebola or Marburg vaccine trial done in Africa, and the results show that, given separately or together, both vaccines were well tolerated and elicited antigen-specific humoral and cellular immune responses. These findings have contributed to the accelerated development of more potent Ebola virus vaccines that encode the same wild-type glycoprotein antigens as the EBO vaccine, which are being assessed during the 2014 Ebola virus disease outbreak in west Africa. FUNDING: US Department of Defense Infectious Disease Clinical Research Program and US National Institutes of Health Intramural Research Program.

First-in-human evaluation of a hexon chimeric adenovirus vector expressing HIV-1 Env (IPCAVD 002).

BACKGROUND: We report the first-in-human safety and immunogenicity assessment of a prototype hexon chimeric adenovirus (Ad) serotype 5 (Ad5) vector containing the hexon hypervariable regions of Ad serotype 48 (Ad48) and expressing human immunodeficiency virus (HIV) type 1 EnvA. METHODS: Forty-eight Ad5 and Ad48 seronegative, HIV-uninfected subjects were enrolled in a randomized, double-blind, placebo-controlled, dose escalation phase 1 study. Four groups of 12 subjects received 10(9) to 10(11) viral particles (vp) of the Ad5HVR48.EnvA.01 vaccine (n = 10 per group) or placebo (n = 2 per group) at week 0 or weeks 0, 4, and 24. Safety and immunogenicity were assessed. RESULTS: Self-limited reactogenicity was observed after the initial immunization in the highest (10(11) vp) dose group. Responses in vaccinees included Ad48 neutralizing antibody (nAb) titers higher than Ad5 nAb titers, EnvA-specific enzyme-linked immunosorbent assay titers, and EnvA-specific enzyme-linked immunospot assay responses, and these responses generally persisted at week 52. At week 28 in the 10(9), 10(10), and 10(11) vp 3-dose groups, geometric mean EnvA enzyme-linked immunosorbent assay titers were 5721, 10 929, and 3420, respectively, and Ad48 nAb titers were a median of 1.7-fold higher than for Ad5. CONCLUSIONS: Ad5HVR48.ENVA.01 was safe, well tolerated, and immunogenic at all doses tested. Vector-elicited nAb responses were greater for Ad48 than Ad5, confirming that Ad-specific nAbs in humans are primarily, but not exclusively, directed against the hexon hypervariable regions. Clinical Trials Registration. NCT00695877.