Safety and immunogenicity of the bi-cistronic GLS-5310 COVID-19 DNA vaccine delivered with the GeneDerm suction device

The CoV2-001 Phase 1 randomized trial evaluated the safety and immunogenicity of the GLS-5310 bi-cistronic DNA vaccine through 48 weeks of follow-up.Forty-five vaccine-naïve participants were recruited between 31 December 2020 and 30 March 2021. GLS-5310, encoding for the SARS-CoV-2 spike (S) and ORF3a proteins, was administered intradermally at 0.6 mg or 1.2 mg per dose, followed by application of the GeneDerm suction device as part of a two-dose regimen spaced either 8 or 12 weeks between vaccinations.GLS-5310 was well tolerated with no SAE's reported. Antibody and T cell responses were dose-independent. Anti-S antibodies were induced in 95.5% of participants with average GMT of ∼480 four-weeks post-vaccination, and declined minimally through 48 weeks. Neutralizing antibodies were induced in 55.5% of participants with post-vaccination GMT of 28.4. T cell responses were induced in 97.8% of participants, averaged 716 SFU/10GLS-5310 administered with the GeneDerm suction device was well tolerated and induced high levels of binding antibodies and T-cell responses. Antibody responses were similar to other DNA vaccines, whereas T cell responses were many-fold greater than DNA and non-DNA vaccines.