The move is part of the New York drugmaker's five-point plan to work together with peers to address the coronavirus pandemic.
“From the beginning it was clear that no one company or innovation would be able to bring an end to the covid-19 crisis," Pfizer Chief Executive Albert Bourla said in a statement.
"Pfizer’s agreement with Gilead is an excellent example of members of the innovation ecosystem working together to deliver medical solutions.”
In July, Gilead, Foster City, Calif., released positive results from its remdesivir tests, showing a 62% reduction in mortality rates for coronavirus patients treated with the treatment.
Worldwide, more than 19 million cases of the disease have been confirmed, with 712,000 people dying. In the U.S. nearly 5 million cases of the disease have been confirmed, with 162,000 deaths. More than 1,000 people in the U.S. die from the disease daily.
In June, Gilead said remdesivir would cost $2,340 for a five-day treatment, a price the company said was well below the market price for the drug.
Pfizer is one of the world's largest drugmakers, and it hopes to leverage its production channels to help Gilead get remdesivir out quickly.
“As one of the largest manufacturers of vaccines, biologics and sterile injectables, it is a privilege to offer our expertise and infrastructure to help fight this pandemic," Bourla said.
"In that spirit, we are pleased that Gilead is using our manufacturing capacity to help facilitate supply of this medicine to patients as quickly as possible."
In July, the U.S. placed a $2 billion order for 100 million doses of Pfizer and BioNTech's coronavirus treatment candidate. The agreement enables the government to acquire up to an additional 500 million doses.
At last check Pfizer shares were 0.5% higher at $38.46 and Gilead shares were up 0.3% at $68.98.