A unit of Insys Therapeutics Inc pleaded guilty on Friday to fraud charges as part of an $225 million deal with the U.S. Justice Department resolving claims that the drugmaker bribed doctors to prescribe an addictive opioid medication.

The plea, in federal court in Boston by the Chandler, Arizona-based Insys’ operating subsidiary, came in one of the few criminal prosecutions to date of a corporation accused of helping fuel the nation’s deadly opioid epidemic.

The plea deal was announced on Wednesday, a month after a federal jury found wealthy Insys founder John Kapoor and four other former executives and managers guilty of engaging in a vast racketeering conspiracy.