Marathon Pharmaceuticals LLC was a privately held biopharmaceuticals company focused on drugs for people with rare diseases.

[9] The company was criticized for their business model which uses regulatory loopholes and FDA incentives to cheaply acquire drugs to treat rare diseases and multiplying the list price to make a profit.

On February 13, 2017, the CEO of Marathon, Jeff Aronin, announced that after four years of development and over 17 trials, the company was granted FDA approval for deflazacort (Emflaza)[17] to treat Duchenne muscular dystrophy, a rare disease that affects approximately 15,000 young boys in the U.S.

[18] Amid controversy over the proposed $89,000 wholesale price to payers, Marathon sold Emflaza and related assets to PTC Therapeutics, a firm with a 20-year history in Duchenne drug development.

[19] According to The Wall Street Journal, the price Marathon was proposing was "roughly 70 times" more than deflazacort would cost overseas, such as in Europe where it was approved to treat 23 indications for a patient base of 83 million.