The US has effectively secured the entire world’s supply of one of only two drugs proven to help treat coronavirus.
The US Department of Health and Human Services (HSS) has now announced it has bought up more than 500,000 doses of the drug.
The figure equates to Gilead’s entire production for July, as well as 90 per cent of its production in both August and September.
The US’s decision to stockpile the drug means there will likely be little supply in the rest of the world for several months.
“To the extent possible, we want to ensure that any American patient who needs remdesivir can get it,” Mr Azar added.
“The Trump Administration is doing everything in our power to learn more about life-saving therapeutics for COVID-19 and secure access to these options for the American people.”
Gilead has been criticised in recent days for its decision to charge $2,340 (£1,990) for a typical remdesivir treatment course for people covered by government health programmes in the US and other developed countries.
In 127 poor or middle-income countries, Gilead is allowing generic makers to supply the drug; two countries are doing that for around $600 per treatment course.
“We’re in uncharted territory with pricing a new medicine, a novel medicine, in a pandemic,” Gilead's chief executive, Dan O'Day, said.
He added the company believed it had to “really deviate from the normal circumstances” and price the drug to ensure wide access rather than based solely on value to patients.
But Peter Maybarduk, a lawyer at the consumer group Public Citizen, called the pricing “an outrage.”
“Remdesivir should be in the public domain” because the drug received at least $70m in public funding towards its development, he added.
“The price puts to rest any notion that drug companies will ‘do the right thing’ because it is a pandemic,” Dr Peter Bach, a health policy expert at Memorial Sloan Kettering Cancer Center in New York said.
“The price might have been fine if the company had demonstrated that the treatment saved lives. It didn’t.”
Additional reporting by AP