On Jul. 1, 2021, HDT Bio announced the U.S. Food and Drug Administration had reviewed the companyﾒs Investigational New Drug Application and provided a notice to proceed for a US-based Phase 1 clinical trial of its HDT-301 COVID-19 RNA vaccine. HDT-301 was also designed to provide protection against variants of SARS-CoV-2, the virus that causes COVID-19.