Phase 1 clinical trial of Hantaan and Puumala virus DNA vaccines delivered by needle-free injection

Abstract

Hantaan virus (HTNV) and Puumala virus (PUUV) are pathogenic zoonoses found in Asia and Europe, respectively. We conducted a randomized Phase 1 clinical trial of individual HTNV and PUUV DNA vaccines targeting the envelope glycoproteins (GnGc), as well as a combined HTNV/PUUV DNA vaccine delivered at varying doses using the PharmaJet Stratis® needle-free injection system (NCT02776761). Cohort 1 and 2 vaccines consisted of 2 mg/vaccination of HTNV or PUUV plasmid, respectively. Cohort 3 vaccine consisted of 2 mg/vaccination of 1:1 mixture of HTNV and PUUV vaccines. Vaccinations were administered on Days 0, 28, 56, and 168. The vaccines were safe and well tolerated. Neutralizing antibody responses were elicited in 7/7 (100%) subjects who received the HTNV DNA (Cohort 1) and 6/6 (100%) subjects who received the PUUV DNA (Cohort 2) vaccines alone. The combination vaccine resulted in 4/9 (44%) seroconversion against both viruses. After the first two vaccinations, the seroconversion rates for the HTNV and PUUV vaccines were >80%.

Fig. 1. Participant flow diagram, NCT02776761.

The randomization and flow of 27 subjects into cohorts and the tracking of those subjects through vaccinations on days 0, 28, 56, and 168. HTNV Hantaan virus, PUUV Puumala virus.

Fig. 2. Adverse events (AE).

The injection site AE (A) and systemic AEs (B) for the three treatment groups: HTNV= pWRG/HTN-M(co) DNA vaccine, PUUV= pWRG/PUU-M(s2) DNA vaccine, and HTNV/PUUV= subjects vaccinated with the combined HTNV and PUUV DNA vaccines.

Fig. 3. Neutralizing antibodies as measured by PsVNA.

PUUV and HTNV PsVNA50 titers for each subject at each timepoint grouped by cohort on the indicated day (0, 28, 56, 168 or 0, 56, and 168). A Symbol color for cohorts legend. B Individual PUUV and HTNV PsVNA50 titers. C Geometric mean titers (GMT) PUUV and HTNV PsVNA50 titers. The limit of quantitation was a PsVNA50 titer of 20 (gray shaded area). Subjects not included in the Immunogenicity Population are shown as open circles (not included in GMT determination). Dashed vertical lines indicate days of vaccinations. * indicates a significantly different (p ≤ 0.05) response between at least two groups using mixed model ANOVA.

Fig. 4. PRNT50 titers.

A Symbol color for cohorts legend, B PRNT50 titers for individual subjects at the indicated timepoints for PUUV (left panel) and HTNV (right panel). Subjects not included in the Immunogenicity Population are shown as open circles (not included in GMT determination). C GMT for Immunogenicity Population for each cohort at each timepoint. Dashed vertical lines indicate days of vaccinations. * indicates a significantly different (p ≤ 0.05) response between at least two groups using mixed model ANOVA.

Fig. 5. DOBV and SEOV cross-neutralization.

A DOBV PsVNA and PRNT titers. B SEOV PsVNA and PRNT. The tick marks from left to right for each subject are days 0, 84, and 196. H, P, and C indicate that the vaccine was HTNV, PUUV, and HTNV/PUUV combination, respectively. An X indicates subject was excluded from the Immunology Population.

Fig. 6. HTNV vs. PUUV cross-neutralization in vaccinated individuals.

PsVNA50 titers of immunogenicity population subjects with Day 196 samples were plotted. Results from Pearson product-moment correlation of log-transformed PsVNA50 titers for each cohort were determined. There was a moderate to strong correlation for cohort 3 (P < 0.05).