March 23 (UPI) -- Pfizer announced Tuesday it's beginning a U.S.-based early-stage study of an oral antiviral drug to treat COVID-19.
The antiviral candidate, called PF-07321332, is what's known as a protease inhibitor and could be prescribed to patients showing the first signs of a COVID-19 infection. The pharmaceutical company said the antiviral clinical candidate might be able to address future coronavirus threats, as well.
"Tackling the COVID-19 pandemic requires both prevention via vaccine and targeted treatment for those who contract the virus," Mikael Dolsten, chief scientific officer and president of worldwide research, development and medical at Pfizer, said in a statement.
"Given the way that [the virus] is mutating and the continued global impact of COVID-19, it appears likely that it will be critical to have access to therapeutic options both now and beyond the pandemic."
The Phase 1 trial will involve health adults to evaluate safety and tolerability of the drug.
Protease inhibitors work by binding to a viral enzyme, preventing a virus from replicating inside a cell. Such therapeutics have been used to treat HIV and hepatitis C.
The Food and Drug Administration has already granted emergency use authorization to the antiviral remdesivir to treat COVID-19. It was developed to treat the Ebola virus.
Former President Donald Trump was given multiple doses of the drug after he was hospitalized in October. The World Health Organization has since recommended against using remdesivir in COVID-19 patients because it said it's had "no meaningful effect on mortality" or other outcomes.
Meanwhile, the results of a Phase 2 trial of an experimental hepatitis D antiviral drug showed that it appears to speed recovery times for non-hospitalized COVID-19 patients. Those given peginterferon-lambda were four times as likely to have cleared the COVID-19 infection within seven days compared to those who received a placebo.
Pfizer, in its partnership with BioNTech, received the FDA's first emergency use authorization for a vaccine to prevent COVID-19 in late 2020.
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National Institutes of Health official Dr. Anthony Fauci (C) speaks about the coronavirus during a press briefing at the White House in Washington, D.C. Health and Human Services Secretary Alexander Azar (L) announced that the United States is declaring the virus a public health emergency and issued a federal quarantine order of 14 days for 195 Americans. Photo by Leigh Vogel/UPI | License Photo