Gene therapy shows promise in muscular dystrophy battle

WASHINGTON - A new study in monkeys has put scientists one step closer to clinical trials to test a gene delivery strategy to improve muscle mass and function in patients with certain degenerative muscle disorders.

Severe weakness of the quadriceps is a defining feature of several neuromuscular disorders.

The study by researchers at Nationwide Children’s Hospital has shown that a gene delivery strategy that produces follistatin - a naturally occurring protein that inhibits myostatin, a growth factor expressed specifically in skeletal muscle - directly to the quadriceps of non-human primates results in long-term gene expression with muscle enhancing effects, including larger muscles with greater strength.

Muscle growth occurred for 12 weeks after treatment, after which time the growth rates appeared to stabilize and were well tolerated, with no adverse events noted over the course of the 15-month study.

“Our studies indicate that this relatively non-invasive approach could have long-term effects, involve few risks and could potentially be effective in various types of degenerative muscle disorders including multiple forms of muscular dystrophy,” said the study’s co-author, Brian Kaspar, principal investigator in the Center for Gene Therapy of The Research Institute at Nationwide Children’s Hospital.

Jerry Mendell, principal investigator in the Center for Gene Therapy at Nationwide Children’s added, “These findings serve as the basis for testing in patients and give us confidence in moving forward with our translational program of follistatin to enhance muscle mass.”

The potential use of this strategy for muscle strengthening has important implications for patients with muscle diseases including Duchenne muscular dystrophy - the most common form of muscular dystrophy - as well as for the planned first clinical trial for inclusion body myositis.

It also may be applicable to other forms of muscular dystrophy, such as facioscapulohumeral muscular dystrophy, in which gene replacement or other types of gene manipulation are not feasible because of the absence of a specific gene defect.

The study appears in Science Translational Medicine. (ANI)