Synacthen Depot is a depot formulation of Synacthen (tetracosactide), a synthetic 24 amino acid melanocortin receptor agonist.
It is approved and marketed outside the US for several autoimmune and inflammatory conditions.
The FDA fast track designation is meant to allow the development and expedite the review of drugs to treat severe conditions.
The designation must be requested by the company at any time during the drug development process.
The agency will review the request and attempt to make a decision within sixty days.
Mallinckrodt senior vice president and chief scientific officer Steven Romano said: "We are pleased with the FDA's determination that our IND application for use of Synacthen Depot in treatment of Duchenne muscular dystrophy meets the agency's established criteria for a Fast Track designation, and are happy to report the first patients have been dosed in the initial phase 1 trial.
"DMD is a devastating disease for which there are few effective treatment options, and Mallinckrodt believes Synacthen Depot may have potential to offer physicians and patients a new alternative."
DMD is a genetic disorder characterized by progressive muscle degeneration and weakness. It is caused by an absence of dystrophin, a protein which helps keep muscle cells intact.