Inovio Pharmaceuticals, Inc. announced the online preprint publication in MedRxiv of Phase 1 clinical data on homologous boosting of its COVID-19 DNA vaccine candidate, INO-4800. The paper, titled "SARS-CoV-2 DNA Vaccine INO-4800 Induces Durable Immune Responses Capable of Being Boosted in a Phase 1 Open-Label Trial," found that among the full Phase 1 cohort of 120 participants – of which 82.5%, or 99 participants, received a booster (or third) dose – INO-4800 produced robust immune responses and was well-tolerated as both a two-dose series and as a homologous booster dose in all adults, including participants 65 years of age and older. Of note, a durable antibody response was observed six months following the second dose, and a homologous booster dose administered 6 to 10.5 months following the second dose also significantly increased antibody and T cell responses. INO-4800 was well-tolerated, with no treatment-related serious adverse events reported. Most adverse events were mild in severity and did not increase in frequency with age and subsequent dosing.