MNK

Mallinckrodt Plc

A specialty biopharmaceutical company that develops and sells branded medicines for rare and hard-to-treat conditions, including the long-used H.P. Acthar Gel. It began in 1867 when three Mallinckrodt brothers, fresh from studying chemistry in Germany, set up a chemical works on their family farm in St. Louis—at the time the only company of its kind west of Philadelphia. In late 2025 it spun off its generics business and rebranded as Keenova Therapeutics.