Eteplirsen Improves Walking Ability in Duchenne Muscular Dystrophy

The FDA is set to make a decision on the NDA by late February, 2016.

The latest data from a phase IIb trial show that eteplirsen provides a statistically significant advantage in the ability to walk in patients with Duchenne muscular dystrophy (DMD). The drug, manufactured by Sarepta Therapeutics, Inc., had previously been granted Orphan Drug Designation, Fast Track Status, and Priority Review status by the FDA.

Eteplirsen is designed to enable the production of a functional dystrophin protein in patients with mutations amendable to exon 51 skipping. Approximately 13% of people with DMD have a mutation targeted by eteplirsen/exon 51 skipping. By skipping the exon, the drug amends the gene’s ability to create a shorter, but still functional, form of dystrophin from mRNA that may help to stabilize or slow the DMD disease process and prolong and improve patient quality of life.

Data shows that DMD patients who were treated with eteplirsen experienced a statistically significant 151-meter difference in the six-minute walk test (6MWT) at three years compared to external DMD controls. Patients treated with eteplirsen also had a lower rate of loss of ambulation over three years and experienced a slower rate of decline through week 192 than controls. Overall, pulmonary functions remained relatively stable through approximately four years in patients treated with eteplirsen.

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“We are encouraged by the positive clinical outcomes, such as the statistically significant difference in the 6MWT in eteplirsen-treated patients compared to a control, especially since we see them accompanied by data that continues to demonstrate exon skipping and dystrophin production in most patients,” said Edward Kaye, MD, interim CEO and chief medical officer of Sarepta, in a news release.

In addition, data from a fourth biopsy confirmed exon skipping in 100% of patients after 180 weeks of treatment, as well as an increase in percent dystrophin-positive fibers and dystrophin intensity in treated patients compared to controls.

The safety profile of eteplirsen has remained consistent with prior results, with the most common adverse reactions being flushing, erythema, and mild temperature elevation.

The FDA has set a Prescription Drug User Fee Act (PDUFA) action date of February 26, 2016 for a decision on the new drug application.

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