Mallinckrodt ARD Inc., formerly known as Questcor Pharmaceuticals, Inc., and its parent company, Mallinckrodt plc, agreed to pay $100 million to settle charges that they violated the antitrust laws when Questcor acquired the rights to a drug that threatened its monopoly in the U.S. market for adrenocorticotropic hormone (ACTH) drugs. Acthar is a specialty drug used as a treatment for infantile spasms, a rare seizure disorder afflicting infants, as well a drug of last resort used to treat other serious medical conditions. The complaint alleges that, while benefitting from an existing monopoly over the only U.S. ACTH drug, Acthar, Questcor illegally acquired the U.S. rights to develop a competing drug, Synacthen Depot. The acquisition stifled competition by preventing any other company from using the Synacthen assets to develop a synthetic ACTH drug, preserving Questcor’s monopoly and allowing it to maintain extremely high prices for Acthar. In addition to the $100 million monetary payment, the proposed stipulated court order, which must be approved by the federal court, requires that Questcor grant a license to develop Synacthen Depot to treat infantile spasms and nephrotic syndrome to a licensee approved by the Commission.