Questcor Pharmaceuticals was an American biopharmaceutical company primarily known for manufacturing and marketing H.P. Acthar Gel (repository corticotropin injection), a drug used to treat various autoimmune and inflammatory conditions. The company was founded in 1992 and was headquartered in Anaheim, California. The company’s main product, Acthar Gel, was originally developed by Armour Pharmaceutical Company in the 1950s. Questcor acquired the rights to Acthar in 2001 and subsequently implemented a controversial pricing strategy, significantly increasing the drug’s cost from approximately $1,650 to $23,000 per vial in 2007, and later to over $28,000 by 2013. Questcor focused on treating serious, difficult-to-treat autoimmune and inflammatory disorders, including multiple sclerosis exacerbations, infantile spasms, nephrotic syndrome, and rheumatology-related conditions. The company’s business model centered on acquiring and marketing specialty pharmaceutical products. In 2014, Mallinckrodt Pharmaceuticals acquired Questcor for approximately $5.6 billion. The acquisition was notable for its significant premium over Questcor’s market value and came amid controversy surrounding the company’s pricing practices and marketing strategies. The deal effectively ended Questcor’s independent operations, with its products being integrated into Mallinckrodt’s portfolio.