Teva settled with the Federal Trade Commission over subsidiary Cephalon’s pay-for-delay deal for sleep apnea and narcolepsy drug Provigil. Teva agreed to pay $1.2 billion to refund buyers that overpaid for the drug.

Antitrust regulators alleged in 2008 that Cephalon paid four generic drugmakers more than $300 million to to prevent the launch of a generic version of Provigil, according to The New York Times. Teva acquired Cephalon in 2011 for $6.8 billion.

FTC officials declined to disclose how much Cephalon benefited from the lack of competition.

“Today’s landmark settlement is an important step in the FTC’s ongoing effort to protect consumers from anticompetitive pay for delay settlements, which burden patients, American businesses, and taxpayers with billions of dollars in higher prescription drug costs,” said FTC Chairwoman Edith Ramirez.