Genexine’s investigational recombinant Covid-19 DNA vaccine has demonstrated safety and immunogenicity in first-in-human trials, getting a step closer to clinical development of homegrown coronavirus vaccine.

The South Korean company announced Wednesday that a phase 1 clinical trial of its SARS-CoV-2 vaccine candidate GX-19N was completed with positive data.

GX-19N contains plasmid DNA encoding SARS-CoV-2 spike protein and plasmid DNA encoding SARS-CoV-2 receptor binding domain (RBD) foldon and nucleocapsid protein (NP).

The trial was performed in 21 healthy adults aged 19-55 years, who received two 3.0 mg vaccine injections four weeks apart.

Ten participants reported 22 treatment-emergent adverse events after vaccination. All solicited AEs were mild except two cases of systemic AEs. There were no cases of serious AEs or discontinuation due to AEs, and AEs did not increase even after second shots, according to the company.

Seventeen in 20 participants showed an over four-fold increase in immunogenicity assessed by anti-SARS-CoV-2-spike and RBD binding antibody levels. The neutralizing antibody response also significantly increased after vaccination.

GX-19N induced stronger T cell responses comparable to or higher than those observed in convalescent adults. The vaccine candidate also induced NP-specific T cell responses in participants whose NP-specific T cell epitopes were identical with those of diverse SARS-CoV-2 variants, suggesting it could enable cross-reactivity to emerging SARS-CoV-2 variants in the UK, South Africa and Brazil.

The phase 1 trial results were published in the medrxiv preprint digital archive.

By Park Yoon-gyun and Minu Kim

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