Pfizer initiates phase 1 study of the novel oral antiviral therapeutic drug against COVID-19 The American company Pfizer Inc, which has created a vaccine against COVID-19, announced that it is progressing to multiple ascending doses after completing the dosing of single ascending doses in a Phase 1 study in healthy adults to evaluate the safety and tolerability of an investigational, novel oral antiviral therapeutic for SARS-CoV-2, the virus that causes COVID-19.