Pfizer has started an early-stage US trial of an oral COVID-19 antiviral therapy that could be prescribed to patients at the first sign of infection, the company said.
The drugmaker, which developed the first authorised coronavirus vaccine in the US with Germany’s BioNTech SA, said the antiviral candidate showed potent activity against SARS-CoV-2, the virus that causes COVID-19, in lab studies.
Pfizer’s candidate, named PF-07321332, is a protease inhibitor that prevents the virus from replicating in cells.
Protease inhibitors have been effective at treating other viral pathogens such as HIV and hepatitis C virus, both on their own and in combination with other antivirals, the company said.
Pfizer believes this class of molecules may provide well-tolerated treatments against COVID-19, as currently marketed therapeutics that work on the same lines have not reported safety concerns.
The company is also studying an intravenously administered antiviral candidate in an early-stage trial in hospitalised COVID-19 patients.
“Together, the two (oral and intravenous candidates) have the potential to create an end-to-end treatment paradigm that complements vaccination in cases where disease still occurs,” Pfizer’s Chief Medical Officer Mikael Dolsten said in a statement.
Pfizer’s candidate is behind two other oral antiviral therapies, which are in mid-stage trials – the first being developed by rival Merck & Co with Ridgeback Bio, and a second from Roche Holding and Atea Pharmaceuticals.
Gilead Sciences’ remdesivir is currently the only US Food and Drug Administration-approved drug for the treatment of COVID-19.
The FDA has granted an emergency authorisation to intravenous therapies from Eli Lilly – bamlanivimab alone and in combination with etesevimab, and a combination therapy from Regeneron.
