Gene Therapy Found to Strengthen Muscles in Monkeys
Many neuromuscular disorders have severe weakness of the quadriceps as a defining feature. This includes Duchenne muscular dystrophy.
Brian Kaspar, PhD, Jerry Mendell, MD, and colleagues at Nationwide Children’s Hospital in Columbus, Ohio are doing gene therapy research which gives hope to future help for patients with neuromuscular disorders. Their current study appears in the November 2009 issue of Science Translational Medicine.
The researchers have 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 monkeys results in long-term gene expression with muscle enhancing effects, including larger muscles with greater strength.
The researchers had previously demonstrated follistatin’s therapeutic potential using rodent models. Moving from mice to monkeys, the researchers produced similar results. The monkeys that received an injection of the follistatin transgene experienced pronounced and durable increases in muscle size and 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. It must be noted that these primates did not have any muscular dystrophy.
A study appearing puts 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.
Dr Mendell noted, “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 research team has developed a plan with the Food and Drug Administration and is currently in the process of performing the formal toxicology and biodistribution studies to support initiating a human clinical trial.
Follistatin Gene Delivery Enhances Muscle Growth and Strength in Nonhuman Primates; Sci Transl Med 11 November 2009:
Vol. 1, Issue 6, p. 6ra15 ; Janaiah Kota, Chalonda R. Handy, Amanda M. Haidet, Chrystal L. Montgomery, Amy Eagle, Louise R. Rodino-Klapac, Danielle Tucker, Christopher J. Shilling, Walter R. Therlfall, Christopher M. Walker, Steven E. Weisbrode, Paul M. L. Janssen, K. Reed Clark, Zarife Sahenk, Jerry R. Mendell and Brian K. Kaspar; [DOI: 10.1126/scitranslmed.3000112]