Sarepta Therapeutics Inc. is embarking on a trial re-do for a new muscle  disorder drug after the U.S. Food and Drug Administration (FDA) said data from previous trials was not sufficient for approval about five months ago.

The drug in question is called eteplirsen , and could be used to treat Duchenne muscular dystrophy (DMD), Reuters reported. The degenerative disorder significantly effects muscle movement, and is believed to be present in about 3,600 male newborns.

Health regulators did not find past trials sufficient because new DMD data was recently released and a similar drug, manufactured by Prosensa Holding NV, failed its own trials.

"Sarepta's announcement also sent Prosensa shares up 28 percent to $6.50 in premarket trade on Monday.

Cambridge, Massachusetts-based Sarepta now plans to submit a marketing application for eteplirsen by the end of the year under an accelerated approval pathway, as suggested by the FDA.

An accelerated approval is usually granted to drugs that treat a serious disease with no treatment options, based on initial trial data. However, the drugmaker still needs to conduct larger trials to prove the initial findings.

Eteplirsen is intended to work by increasing the production of a protein called dystrophin, the lack of which is the chief cause of DMD.

The FDA said the drug failed to show "statistically significant improvement" in the distance the patients with DMD were able to walk.

The drug company now plans to submit a marketing application for the drug under the "accelerated improvement pathway," Reuters reported.

Accelerated approval tends to be granted to drugs that could potentially treat a serious disease that does not have many FDA approved treatment options.

Babies who have DMD often walk later than other children, parents may also notice enlarged calf muscles, MDA.org reported. The child may be clumsier than other children in preschool and have trouble climbing stairs or participating in other physical activities. These children will usually be using a wheelchair by the age of 12.

Muscle deterioration associated with the condition is usually painful and affected children can experience cardiovascular and respiratory issues.