Eric Hoffman, of Children's Research Institute at Children's National Medical Center in Washington, said the study involved application of a nucleic acid drug called PRO051. This approach was shown to reactivate dystrophin protein production in small areas of muscle tissue at the injection site of muscular dystrophy patients.

"Dozens of specific sequences will be required for effectively treating the majority of patients with Duchenne muscular dystrophy," Hoffman said in a statement.

"But in order to realize the promise of personalized molecular medicine in muscular dystrophies and, ultimately, other disorders, it will be important to re-evaluate current measures of toxicity, efficacy, and marketing that ensure both safety for the patient, as well as rapid development and distribution of life-saving drugs."

The findings are published in the New England Journal of Medicine.

Duchenne muscular dystrophy affects about 1 in 3,500 boys of all races and ethnicities worldwide.