The U.S. Food and Drug Administration maintained its decision to reject PTC Therapeutics Inc.'s Duchenne muscular dystrophy treatment, ataluren.

Duchenne muscular dystrophy is a genetic disorder characterized by progressive muscle degeneration and weakness.

The U.S. regulator rejected the drug in October 2017, prompting PTC Therapeutics to file an appeal. The regulator's office of new drugs has reiterated the decision.

The company is required to submit additional data before the regulator can approve the medicine.