Pfizer starts Phase 2/3 study of COVID-19 oral antiviral candidate for adults exposed to virus

Pfizer Inc. PFE, -0.28% said Monday it is starting a Phase 2/3 trial of its investigational novel oral antiviral candidate to treat adults living in a household with someone who has tested positive for and has symptoms of the coronavirus-borne illness COVID-19. The candidate is called PF007321332 and is co-administered with a low dose of ritonavir to prevent infection. "If successful, we believe this therapy could help stop the virus early -- before it has had a chance to replicate extensively -- potentially preventing symptomatic disease in those who have been exposed and inhibiting the onset of infection in others," said Mikael Dolsten, MD, PhD., chief scientific officer and president, Worldwide Research, Development and Medical of Pfizer. The study will enroll up to 2,660 healthy adults aged 18 and older. Pfizer shares were slightly higher premarket and have gained 19% in the year to date, while the Dow Jones Industrial Average DJIA, +0.51% has gained 13.7%.