The complaint, filed under the U.S. False Claims Act, accuses the New-York based company of failing to report price concessions on its drug Eylea, which is used to treat neovascular Age-Related Macular Degeneration.

"The government alleges that Regeneron manipulated Medicare's drug pricing process, by knowingly failing to report its payment of credit card processing fees as price concessions to its customers," said Acting U.S. Attorney Joshua Levy said in a written statement.

"By doing so, Regeneron greatly inflated the costs of its drug to Medicare over many years and enhanced its revenues," Levy said.

A spokeswoman for Regeneron did not immediately respond to a request by Reuters for comment.

(Reporting by Dan Whitcomb; editing by Costas Pitas)