Pfizer starts early stage trial for oral COVID-19 drug

Pfizer on Tuesday said it has begun early stage U.S. clinical trials of an investigational, oral antiviral drug for COVID-19.

According to the company, the candidate “has demonstrated potent in vitro antiviral activity” against the virus that causes COVID-19, as well as activity against other coronaviruses, suggesting the potential for use to address future threats. 

The candidate is a class of drug known as a protease inhibitor, which has been long used used to treat HIV and hepatitis C. The drugs work by blocking a critical enzyme, a protease, that the virus needs to replicate.

“Tackling the COVID-19 pandemic requires both prevention via vaccine and targeted treatment for those who contract the virus. Given the way that SARS-CoV-2 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,” Mikael Dolsten, Pfizer’s chief scientific officer, said in a statement.

Dolsten said the drug candidate could be prescribed at the first sign of infection, without requiring that patients are hospitalized or in critical care.

Pfizer is also testing an intravenously administered investigational protease inhibitor for patients who are hospitalized with COVID-19.

Pfizer already has an authorized COVID-19 vaccine on the market that it developed with its German partner BioNTech, but the development of therapeutics has not been as successful. 

Gilead Sciences’s remdesivir is currently the only Food and Drug Administration-approved drug for the treatment of COVID-19. The FDA has granted emergency authorization to two antibody therapies, from Regeneron and Eli Lilly, respectively. 

Health experts say there needs to be a range of treatments, not just vaccines, in order to completely end the pandemic.